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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Determining cosmic microwave background anisotropies in the presence of foregrounds  

E-Print Network [OSTI]

Separating foregrounds from the signal is one of the big challenges in cosmic microwave background (CMB) experiments. A simple way to estimate the CMB temperature in a given pixel is to fit for the amplitudes of the CMB and the various foreground components. The variance squared of this estimator is shown to be equal to $[(FDF)^2\\ \\sigzt + \\sigsh^2]$, where $\\sigz$ is the variance in the absence of foregrounds; $\\sigsh$ is the variance due to the uncertainty in the shapes of the foreground components; and FDF is the {\\it foreground degradation factor}. This one number, the FDF, gives a good indication of the ability of a given experiment to disentangle the CMB from foreground sources. A variety of applications relating to the planning and analyzing of experiments is presented.

Scott Dodelson

1995-12-05T23:59:59.000Z

2

Neural networks and separation of background and foregrounds in astrophysical sky maps  

E-Print Network [OSTI]

The Independent Component Analysis (ICA) algorithm is implemented as a neuralnetwork for separating signals of different origin in astrophysical sky maps.Due to its self-organizing capability, it works without prior assumptions onthe signals, neither on their frequency scaling, nor on the signal mapsthemselves; instead, it learns directly from the input data how to separate thephysical components, making use of their statistical independence. To test thecapabilities of this approach, we apply the ICA algorithm on sky patches, takenfrom simulations and observations, at the microwave frequencies, that are goingto be deeply explored in a few years on the whole sky, by the MicrowaveAnisotropy Probe (MAP) and by the {\\sc Planck} Surveyor Satellite. The maps areat the frequencies of the Low Frequency Instrument (LFI) aboard the {\\scPlanck} satellite (30, 44, 70 and 100 GHz), and contain simulated astrophysicalradio sources, Cosmic Microwave Background (CMB) radiation, and Galacticdiffuse emissions from thermal dust...

Baccigalupi, C; Burigana, C; De Zotti, G; Farusi, A; Maino, D; Maris, M; Perrotta, F; Salerno, E; Toffolatti, L; Tonazzini, A

2000-01-01T23:59:59.000Z

3

FOREGROUND PREDICTIONS FOR THE COSMIC MICROWAVE BACKGROUND POWER SPECTRUM FROM MEASUREMENTS OF FAINT INVERTED RADIO SOURCES AT 5 GHz  

SciTech Connect (OSTI)

We present measurements of a population of matched radio sources at 1.4 and 5 GHz down to a flux limit of 1.5 mJy in 7 deg{sup 2} of the NOAO Deep Field South. We find a significant fraction of sources with inverted spectral indices that all have 1.4 GHz fluxes less than 10 mJy and are therefore too faint to have been detected and included in previous radio source count models that are matched at multiple frequencies. Combined with the matched source population at 1.4 and 5 GHz in 1 deg{sup -2} in the ATESP survey, we update models for the 5 GHz differential number counts and distributions of spectral indices in 5 GHz flux bins that can be used to estimate the unresolved point source contribution to the cosmic microwave background temperature anisotropies. We find a shallower logarithmic slope in the 5 GHz differential counts than in previously published models for fluxes {approx}< 100 mJy as well as larger fractions of inverted spectral indices at these fluxes. Because the Planck flux limit for resolved sources is larger than 100 mJy in all channels, our modified number counts yield at most a 10% change in the predicted Poisson contribution to the Planck temperature power spectrum. For a flux cut of 5 mJy with the South Pole Telescope and a flux cut of 20 mJy with the Atacama Cosmology Telescope, we predict a {approx}30% and {approx}10% increase, respectively, in the radio source Poisson power in the lowest frequency channels of each experiment relative to that predicted by previous models.

Schneider, Michael D. [Lawrence Livermore National Laboratory, P.O. Box 808 L-210, Livermore, CA 94551 (United States); Becker, Robert H. [Department of Physics, University of California, One Shields Avenue, Davis, CA 08991 (United States); De Vries, Willem [Lawrence Livermore National Laboratory, P.O. Box 808 L-211, Livermore, CA 94551 (United States); White, Richard L., E-mail: schneider42@llnl.gov [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

2012-05-10T23:59:59.000Z

4

Controlling Beaver Damage  

E-Print Network [OSTI]

Beavers are important because their dams stabilize creek flow, slow runoff and create ponds. However, these same dams can negatively alter the flow of creeks. Damage prevention, control and various trapping methods are discussed in this publication....

Texas Wildlife Services

2007-03-13T23:59:59.000Z

5

Pennsylvania Nuclear Profile - Beaver Valley  

U.S. Energy Information Administration (EIA) Indexed Site

Beaver Valley" "Unit","Summer capacity (mw)","Net generation (thousand mwh)","Summer capacity factor (percent)","Type","Commercial operation date","License expiration date"...

6

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Background Solar panels are designed as a photovoltaic module. The energy producing aspect of the photovoltaic module has two primary steps. The first is a semiconducting material...

7

BACKGROUND  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusA t i o n dataWhatNationalBACKGROUND The safe

8

Foreground Removal vs. Foreground Avoidance: Contamination of the EoR Window  

E-Print Network [OSTI]

The removal of the Galactic and extragalactic foregrounds remains a major challenge for those wishing to make a detection of the Epoch of Reionization 21-cm signal. Multiple methods of modelling these foregrounds with varying levels of assumption have been trialled and shown promising recoveries on simulated data. Recently however there has been increased discussion of using the expected shape of the foregrounds in Fourier space to define an EoR window free of foreground contamination. By carrying out analysis within this window only, one can avoid the foregrounds and any statistical bias they might introduce. In this paper we discuss the advantages and disadvantages of both foreground removal and foreground avoidance. We create a series of simulations with noise levels in line with both current and future experiments and compare the recovered statistical cosmological signal from both methods. We also relax the assumption that the foregrounds are smooth by introducing a Gaussian random factor along the line-o...

Chapman, Emma; Abdalla, Filipe

2014-01-01T23:59:59.000Z

9

E-Print Network 3.0 - american beaver castor Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2 Do introduced North American beavers Castor canadensis engineer differently in southern South America? An overview Summary: Do introduced North American beavers Castor canadensis...

10

Microsoft Word - CX_Beaver Creek.doc  

Broader source: Energy.gov (indexed) [DOE]

(BPA) funding to acquire the Beaver Creek property and to maintain this property for fish and wildlife habitat protection. Budget Information: Work Order 00225478 Fish and...

11

Masking line foregrounds in intensity mapping surveys  

E-Print Network [OSTI]

We address the problem of line confusion in intensity mapping surveys and explore the possibility to mitigate line foreground contamination by progressively masking the brightest pixels in the observed map. We consider experiments targeting CO(1-0) at $z=3$, Ly$\\alpha$ at $z=7$, and CII at $z=7$, and use simulated intensity maps, which include both clustering and shot noise components of the signal and possible foregrounds, in order to test the efficiency of our method. We find that for CO and Ly$\\alpha$ it is quite possible to remove most of the foreground contribution from the maps via only 1%-3% pixel masking. The CII maps will be more difficult to clean, however, due to instrumental constraints and the high-intensity foreground contamination involved. While the masking procedure sacrifices much of the astrophysical information present in our maps, we demonstrate that useful cosmological information in the targeted lines can be successfully retrieved.

Breysse, Patrick C; Kamionkowski, Marc

2015-01-01T23:59:59.000Z

12

Foreground removal for SKA EoR with the Correlated Component Analysis  

E-Print Network [OSTI]

We apply the Correlated Component Analysis (CCA) method on simulated data of the Square Kilometre Array, with the aim of accurately cleaning the 21 cm reionization signal from diffuse foreground contamination. The CCA has been developed for the Cosmic Microwave Background, but the application of the Fourier-domain implementation of this method to the reionization signal is straightforward. The CCA is a parametric method to estimate the frequency behaviour of the foregrounds from the data by using second-order statistics. We test its performance on foreground simulations of increasing complexity, designed to challenge the parametric models adopted. We also drop the assumption of spectral smoothness that most of the methods rely upon. We are able to clean effectively the simulated data across the explored frequency range (100-200 MHz) for all the foreground simulations. This shows that the CCA method is very promising for EoR component separation.

Bonaldi, Anna

2014-01-01T23:59:59.000Z

13

An Improved Method for 21cm Foreground Removal  

E-Print Network [OSTI]

21-cm tomography is expected to be difficult in part because of serious foreground contamination. Previous studies have found that line-of-sight approaches are capable of cleaning foregrounds to an acceptable level on large ...

Liu, Adrian

14

E-Print Network 3.0 - ac backgrounder table Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Vachon Summary: -surveillance, optical motion capture and multimedia application. The process mainly used is the background subtraction... as foreground or background. Some...

15

Beaver MCCs and Switchgear  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience ProgramBackground8.0.1Vulture Spatial Ecology

16

The beaver Anchitheriomys from the Miocene of Central Europe  

SciTech Connect (OSTI)

New finds of teeth and mandibles of Anchitheriomys from the Hambach opencast lignite mine in Northwest Germany and the first detailed descriptions of other mandibles from South Germany and Switzerland allow a review of the Central European specimens of this rare beaver genus. The metric variation of cheek teeth and especially the great differences in dimensions of incisors can be much better assessed. The observed range in size can be attributed to ontogenetic changes, and all material is assigned to Anchitheriomys suevicus. Stratigraphically, this species is restricted to the early middle Miocene, European Mammalian Neogene biozones MN 5-6.

Stefen, C.; Mors, T. [Museum Tierkunde, Dresden (Germany)

2008-09-15T23:59:59.000Z

17

City of Beaver City, Nebraska (Utility Company) | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160Benin:Energy InformationLake SouthChroma ATEEnergyAugusta,Barron,Baudette,Beaver

18

Non-gaussianity in the foreground-reduced CMB maps  

E-Print Network [OSTI]

[Abridged]: A detection or nondetection of primordial non-Gaussianity by using the CMB data is crucial not only to discriminate inflationary models but also to test alternative scenarios. Non-Gaussianity offers, therefore, a powerful probe of the physics of the primordial universe. The extraction of primordial non-Gaussianity is a difficult enterprise since several effects of non-primordial nature can produce non-Gaussianity. Most of the Gaussianity analyses of CMB data have been performed by using part-sky frequency, where masks are used to deal with the galactic diffuse foreground emission. However, full-sky map seems to be potentially more appropriate to test for Gaussianity of the CMB data. On the other hand, masks can induce bias in some non-Gaussianity analyses. Here we use two recent large-angle non-Gaussianity indicators, based on skewness and kurtosis of large-angle patches of CMB maps, to examine the question of non-Gaussianity in the available full-sky five-year and seven-year WMAP maps. We show that these full-sky foreground-reduced maps present a significant deviation from Gaussianity of different levels, which vary with the foreground-reducing procedures. We also make a Gaussianity analysis of the foreground-reduced five-year and seven-year WMAP maps with a KQ75 mask, and compare with the similar analysis performed with the full-sky foreground-reduced maps. This comparison shows a significant reduction in the levels of non-Gaussianity when the mask is employed, which provides indications on the suitability of the foreground-reduced maps as Gaussian reconstructions of the full-sky CMB.

A. Bernui; M. J. Reboucas

2010-03-30T23:59:59.000Z

19

Estimating the spectral indices of correlated astrophysical foregrounds by a second-order statistical approach  

E-Print Network [OSTI]

We present the first tests of a new method, the Correlated Component Analysis (CCA) based on second-order statistics, to estimate the mixing matrix, a key ingredient to separate astrophysical foregrounds superimposed to the Cosmic Microwave Background (CMB). In the present application, the mixing matrix is parameterized in terms of the spectral indices of Galactic synchrotron and thermal dust emissions, while the free-free spectral index is prescribed by basic physics, and is thus assumed to be known. We consider simulated observations of the microwave sky with angular resolution and white stationary noise at the nominal levels for the PLANCK satellite, and realistic foreground emissions, with a position dependent synchrotron spectral index. We work with two sets of PLANCK frequency channels: the low frequency set, from 30 to 143 GHz, complemented with the Haslam 408 MHz map, and the high frequency set, from 217 to 545 GHz. The concentration of intense free-free emission on the Galactic plane introduces a steep dependence of the spectral index of the global Galactic emission with Galactic latitude, close to the Galactic equator. This feature makes difficult for the CCA to recover the synchrotron spectral index in this region, given the limited angular resolution of PLANCK, especially at low frequencies. A cut of a narrow strip around the Galactic equator (|b|<3 deg), however, allows us to overcome this problem. We show that, once this strip is removed, the CCA allows an effective foreground subtraction, with residual uncertainties inducing a minor contribution to errors on the recovered CMB power spectrum.

A. Bonaldi; L. Bedini; E. Salerno; C. Baccigalupi; G. De Zotti

2006-09-26T23:59:59.000Z

20

Geology of the Middle Beaver Creek area, Mason and Gillespie Counties, Texas  

E-Print Network [OSTI]

AREA, NASGR AEG GILhNPIR COGRTIES, TEIAB ABSTRACT The Middle Beaver Creek area is situated on the soutlwsst flank of the Llano ?plift region in Mason and Gillespie Counties, Texas Hooks of Presa?brian, Psleosoie, Mesosois, and Genosois age... ' Figure 1. ? Map of' part of Mason and Gillespie Counties, Texass showing location of' the Middle Beaver Creek Area, on aoetats oosered aerial photographs. In order to aoourateIp locate and plot the oontaots asd faults, the photographs vere studies...

Peterson, Don Hamilton

1959-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Selection between foreground models for global 21-cm experiments  

E-Print Network [OSTI]

The precise form of the foregrounds for sky-averaged measurements of the 21-cm line during and before the epoch of reionization is unknown. We suggest that the level of complexity in the foreground models used to fit global 21-cm data should be driven by the data, under a Bayesian model selection methodology. A first test of this approach is carried out by applying nested sampling to simplified models of global 21-cm data to compute the Bayesian evidence for the models. If the foregrounds are assumed to be polynomials of order n in log-log space, we can infer the necessity to use n=4 rather than n=3 with <2h of integration with limited frequency coverage, for reasonable values of the n=4 coefficient. Using a higher-order polynomial does not necessarily prevent a significant detection of the 21-cm signal. Even for n=8, we can obtain very strong evidence distinguishing a reasonable model for the signal from a null model with 128h of integration. More subtle features of the signal may, however, be lost if the...

Harker, Geraint

2015-01-01T23:59:59.000Z

22

Estimating the spectral indices of correlated astrophysical foregrounds by a second-order statistical approach  

E-Print Network [OSTI]

We present the first tests of a new method, the Correlated Component Analysis (CCA) based on second-order statistics, to estimate the mixing matrix, a key ingredient to separate astrophysical foregrounds superimposed to the Cosmic Microwave Background (CMB). In the present application, the mixing matrix is parameterized in terms of the spectral indices of Galactic synchrotron and thermal dust emissions, while the free-free spectral index is prescribed by basic physics, and is thus assumed to be known. We consider simulated observations of the microwave sky with angular resolution and white stationary noise at the nominal levels for the PLANCK satellite, and realistic foreground emissions, with a position dependent synchrotron spectral index. We work with two sets of PLANCK frequency channels: the low frequency set, from 30 to 143 GHz, complemented with the Haslam 408 MHz map, and the high frequency set, from 217 to 545 GHz. The concentration of intense free-free emission on the Galactic plane introduces a ste...

Bonaldi, A; Salerno, E; Baccigalupi, C; De Zotti, G

2006-01-01T23:59:59.000Z

23

Beaver Monitoring Protocol for Forest Service Region 2 Revised May 2008 1 USDA FOREST SERVICE REGION 2  

E-Print Network [OSTI]

HILLS NATIONAL FORESTS (Photo from Nature of New England Website ­ http Black Hills National Forest, USDA Forest Service, Custer, SD Revised May 2008 #12;Beaver MonitoringBeaver Monitoring Protocol for Forest Service Region 2 ­ Revised May 2008 1 USDA FOREST SERVICE

Beck, Jeffrey L.

24

Analysis of Small Scale MBR Anisotropy in the Presence of Foreground Contamination  

E-Print Network [OSTI]

Many of the current round of experiments searching for anisotropies in the MBR are confronting the problem of how to disentangle the cosmic signal from contamination due to galactic and intergalactic foreground sources. Here we show how commonly used likelihood function techniques can be generalized to account for foreground. Specifically we set some restrictions on the spectrum of foreground contamination but allow the amplitude to vary arbitrarily. The likelihood function thus generalized gives reasonable limits on the MBR anisotropy which, in some cases, are not much less restrictive than what one would get from more detailed modeling of the foreground. Furthermore, the likelihood function is exactly the same as one would obtain by simply projecting out foreground contamination and just looking at the reduced data set. We apply this generalized analysis to the recent medium angle data sets of ACME-HEMT and MAX. The resulting analysis constrains the one free parameter in the standard cold dark matter theory to be Q=18_-5^+8 microK. This best fit value, although in striking agreement with the normalization from COBE, is not a very good fit, with an overall chi^2/ degree of freedom =208/168. We also argue against three commonly used methods of dealing with foreground: (i) ignoring it completely; (ii) subtracting off a best fit foreground and treating the residuals as if uncontaminated; and (iii) culling data which appears to be contaminated by foreground.

Scott Dodelson; Albert Stebbins

1993-10-28T23:59:59.000Z

25

Intra-amygdala infusion of the protein kinase Mzeta inhibitor ZIP disrupts foreground context fear memory  

E-Print Network [OSTI]

Intra-amygdala infusion of the protein kinase Mzeta inhibitor ZIP disrupts foreground context fear-pseudosubstrate inhibitory peptide (ZIP) remains in the brain after infusion. Here, we demon- strate that foreground context the brain by 24 h after infusion. These data contribute to a growing body of lit- erature that demonstrates

Helmstetter, Fred J.

26

Towards a free-free template for CMB foregrounds  

E-Print Network [OSTI]

A full-sky template map of the Galactic free-free foreground emission component is increasingly important for high sensitivity CMB experiments. We use the recently published \\ha data of both the northern and southern skies as the basis for such a template. The first step is to correct the \\ha maps for dust absorption using the 100 $\\mu$m dust maps of Schlegel, Finkbeiner & Davis (1998). We show that for a range of longitudes, the Galactic latitude distribution of absorption suggests that it is 33 per cent of the full extragalactic absorption. A reliable absorption-corrected \\ha map can be produced for $\\sim 95$ per cent of the sky; the area for which a template cannot be recovered is the Galactic plane area $|b| 5^{\\circ}$, $l=260^{\\circ}-0^{\\circ}-160^{\\circ}$ and some isolated dense dust clouds at intermediate latitudes. The second step is to convert the dust-corrected \\ha data into a predicted radio surface brightness. The free-free emission formula is revised to give an accurate expression (1 per...

Dickinson, C; Davis, R J

2003-01-01T23:59:59.000Z

27

Model independent foreground power spectrum estimation using WMAP 5-year data  

SciTech Connect (OSTI)

In this paper, we propose and implement on WMAP 5 yr data a model independent approach of foreground power spectrum estimation for multifrequency observations of the CMB experiments. Recently, a model independent approach of CMB power spectrum estimation was proposed by Saha et al. 2006. This methodology demonstrates that the CMB power spectrum can be reliably estimated solely from WMAP data without assuming any template models for the foreground components. In the current paper, we extend this work to estimate the galactic foreground power spectrum using the WMAP 5 yr maps following a self-contained analysis. We apply the model independent method in harmonic basis to estimate the foreground power spectrum and frequency dependence of combined foregrounds. We also study the behavior of synchrotron spectral index variation over different regions of the sky. We use the full sky Haslam map as an external template to increase the degrees of freedom, while computing the synchrotron spectral index over the frequency range from 408 MHz to 94 GHz. We compare our results with those obtained from maximum entropy method foreground maps, which are formed in pixel space. We find that relative to our model independent estimates maximum entropy method maps overestimate the foreground power close to galactic plane and underestimates it at high latitudes.

Ghosh, Tuhin; Souradeep, Tarun [IUCAA, Post Bag 4, Ganeshkhind, Pune-411007 (India); Saha, Rajib [IUCAA, Post Bag 4, Ganeshkhind, Pune-411007 (India); Jet Propulsion Laboratory, M/S 169-327, 4800 Oak Grove Drive, Pasadena, California 91109 (United States); California Institute of Technology, Pasadena, California 91125 (United States); Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016 (India); Jain, Pankaj [Department of Physics, Indian Institute of Technology, Kanpur, U.P, 208016 (India)

2009-06-15T23:59:59.000Z

28

A Strategy to Minimize Dust Foregrounds in B-mode Searches  

E-Print Network [OSTI]

The Planck satellite has identified several patches of sky with low polarized dust emission, obvious targets for searches for the cosmic-microwave-background (CMB) B-mode signal from inflationary gravitational waves. Still, given the Planck measurement uncertainties, the polarized dust foregrounds in these different candidate patches may differ by an order of magnitude or more. Here we show that a brief initial experiment to map these candidate patches more deeply at a single high frequency can efficiently zero in on the cleanest patch(es) and thus improve significantly the sensitivity of subsequent B-mode searches. A ground-based experiment with current detector technology operating at >~220 GHz for 3 months can efficiently identify a low-dust-amplitude patch and thus improve by up to 20%-60% on the sensitivity to cosmic B modes of the subsequent lower-frequency deep integration. A balloon experiment with current detector sensitivities covering the set of patches and operating at ~350 GHz can reach a similar...

Kovetz, Ely D

2015-01-01T23:59:59.000Z

29

Cosmic Dawn and Epoch of Reionization Foreground Removal with the SKA  

E-Print Network [OSTI]

The exceptional sensitivity of the SKA will allow observations of the Cosmic Dawn and Epoch of Reionization (CD/EoR) in unprecedented detail, both spectrally and spatially. This wealth of information is buried under Galactic and extragalactic foregrounds, which must be removed accurately and precisely in order to reveal the cosmological signal. This problem has been addressed already for the previous generation of radio telescopes, but the application to SKA is different in many aspects. In this chapter we summarise the contributions to the field of foreground removal in the context of high redshift and high sensitivity 21-cm measurements. We use a state-of-the-art simulation of the SKA Phase 1 observations complete with cosmological signal, foregrounds and frequency-dependent instrumental effects to test both parametric and non-parametric foreground removal methods. We compare the recovered cosmological signal using several different statistics and explore one of the most exciting possibilities with the SKA ...

Chapman, Emma; Harker, Geraint; Jeli?, Vibor; Abdalla, Filipe B; Bernardi, Gianni; Bobin, Jrme; Dulwich, Fred; Mort, Benjamin; Santos, Mario; Starck, Jean-Luc

2015-01-01T23:59:59.000Z

30

Foreground Removal using FastICA: A Showcase of LOFAR-EoR  

E-Print Network [OSTI]

We introduce a new implementation of the FastICA algorithm on simulated LOFAR EoR data with the aim of accurately removing the foregrounds and extracting the 21-cm reionization signal. We find that the method successfully removes the foregrounds with an average fitting error of 0.5 per cent and that the 2D and 3D power spectra are recovered across the frequency range. We find that for scales above several PSF scales the 21-cm variance is successfully recovered though there is evidence of noise leakage into the reconstructed foreground components. We find that this blind independent component analysis technique provides encouraging results without the danger of prior foreground assumptions.

Chapman, Emma; Harker, Geraint; Jeli?, Vibor; Labropoulos, Panagiotis; Zaroubi, Saleem; Brentjens, Michiel A; de Bruyn, A G; Koopmans, L V E

2012-01-01T23:59:59.000Z

31

OPENING THE 21 cm EPOCH OF REIONIZATION WINDOW: MEASUREMENTS OF FOREGROUND ISOLATION WITH PAPER  

SciTech Connect (OSTI)

We present new observations with the Precision Array for Probing the Epoch of Reionization with the aim of measuring the properties of foreground emission for 21 cm epoch of reionization (EoR) experiments at 150 MHz. We focus on the footprint of the foregrounds in cosmological Fourier space to understand which modes of the 21 cm power spectrum will most likely be compromised by foreground emission. These observations confirm predictions that foregrounds can be isolated to a {sup w}edge{sup -}like region of two-dimensional (k , k{sub Parallel-To })-space, creating a window for cosmological studies at higher k{sub Parallel-To} values. We also find that the emission extends past the nominal edge of this wedge due to spectral structure in the foregrounds, with this feature most prominent on the shortest baselines. Finally, we filter the data to retain only this ''unsmooth'' emission and image its specific k{sub Parallel-To} modes. The resultant images show an excess of power at the lowest modes, but no emission can be clearly localized to any one region of the sky. This image is highly suggestive that the most problematic foregrounds for 21 cm EoR studies will not be easily identifiable bright sources, but rather an aggregate of fainter emission.

Pober, Jonathan C.; Parsons, Aaron R.; Ali, Zaki [Astronomy Department, U. California, Berkeley, CA (United States); Aguirre, James E.; Moore, David F. [Department of Physics and Astronomy, U. Pennsylvania, Philadelphia, PA (United States); Bradley, Richard F. [Department of Electrical and Computer Engineering, U. Virginia, Charlottesville, VA (United States); Carilli, Chris L. [National Radio Astronomy Observatory, Socorro, NM (United States); DeBoer, Dave; Dexter, Matthew; MacMahon, Dave [Radio Astronomy Laboratory, U. California, Berkeley, CA (United States); Gugliucci, Nicole E. [Department of Astronomy, U. Virginia, Charlottesville, VA (United States); Jacobs, Daniel C. [School of Earth and Space Exploration, Arizona State U., Tempe, AZ (United States); Klima, Patricia J. [National Radio Astronomy Observatory, Charlottesville, VA (United States); Manley, Jason; Walbrugh, William P. [Square Kilometer Array, South Africa Project, Cape Town (South Africa); Stefan, Irina I. [Cavendish Laboratory, Cambridge (United Kingdom)

2013-05-10T23:59:59.000Z

32

Opening the 21cm EoR Window: Measurements of Foreground Isolation with PAPER  

E-Print Network [OSTI]

We present new observations with the Precision Array for Probing the Epoch of Reionization (PAPER) with the aim of measuring the properties of foreground emission for 21cm Epoch of Reionization experiments at 150 MHz. We focus on the footprint of the foregrounds in cosmological Fourier space to understand which modes of the 21cm power spectrum will most likely be compromised by foreground emission. These observations confirm predictions that foregrounds can be isolated to a "wedge"-like region of 2D (k-perendicular, k-parallel)-space, creating a window for cosmological studies at higher k-parallel values. We also find that the emission extends past the nominal edge of this wedge due to inherent spectral structure in the foregrounds themselves, with this feature most prominent on the shortest baselines. Finally, we filter the data to retain only this "unsmooth" emission and image it. The resultant image shows an excess of power on large angular scales, but no emission can be clearly localized to any one region...

Pober, Jonathan C; Aguirre, James E; Ali, Zaki; Bradley, Richard F; Carilli, Chris L; DeBoer, Dave; Dexter, Matthew; Gugliucci, Nicole E; Jacobs, Daniel C; MacMahon, Dave; Manley, Jason; Moore, David F; Stefan, Irina I; Walbrugh, William P

2013-01-01T23:59:59.000Z

33

Habitat Evaluation Procedures (HEP) Report; West Beaver Lake Project, Technical Report 2005  

SciTech Connect (OSTI)

On September 7, 2004, the Habitat Evaluation Procedure (HEP) was used to determine baseline habitat suitability on the West Beaver Lake property, an acquisition completed by the Kalispel Tribe of Indians in September 2004. Evaluation species and appropriate models include bald eagle, black-capped chickadee, mallard, muskrat, and white-tailed deer. Habitat Suitability Index (HSI) values were visually estimated and agreed upon by all HEP team members. The West Beaver Lake Project provides a total of 82.69 Habitat Units (HUs) for the species evaluated. Emergent wetland habitat provides 8.80 HUs for mallard, muskrat, and Canada goose. Conifer forest habitat provides 70.33 HUs for bald eagle, black-capped chickadee, mallard, and white-tailed deer. Open water provides 3.30 HUs for mallard, muskrat, and Canada goose. The objective of using HEP at the West Beaver Lake Project and other protected properties is to document the quality and quantity of available habitat for selected wildlife species. In this way, HEP provides information on the relative value of the same area at future points in time so that the effect of management activities on wildlife habitat can be quantified. When combined with other tools, the baseline HEP will be used to determine the most effective on-site management, restoration, and enhancement actions to increase habitat suitability for targeted species. The same process will be replicated every five years to quantitatively evaluate the effectiveness of management strategies in improving and maintaining habitat conditions while providing additional crediting to BPA for enhanced habitat values.

Entz, Ray

2005-05-01T23:59:59.000Z

34

The Fundamental Multi-Baseline Mode-Mixing Foreground in 21 cm EoR Observations  

E-Print Network [OSTI]

The primary challenge for experiments measuring the neutral hydrogen power spectrum from the Epoch of Reionization (EoR) are mode-mixing effects where foregrounds from very bright astrophysical sources interact with the instrument to contaminate the EoR signal. In this paper we identify a new type of mode-mixing that occurs when measurements from non-identical baselines are combined for increased power spectrum sensitivity. This multi-baseline effect dominates the mode-mixing power and can contaminate the EoR window, an area in Fourier space previously identified to be relatively free of foreground power. Multi-baseline mode-mixing introduces characteristic shapes into the three dimensional Fourier space that are determined by the instrumental configuration and we develop an iterative approach to identifying and removing mode-mixed power based on these instrumental shapes.

Hazelton, Bryna J; Sullivan, Ian S

2013-01-01T23:59:59.000Z

35

Non-Gaussianity in the HILC foreground-reduced three-year WMAP CMB map  

E-Print Network [OSTI]

A detection or nondetection of primordial non-Gaussianity in the CMB data is essential not only to test alternative models of the physics of the early universe but also to discriminate among classes of inflationary models. Given this far reaching consequences of such a non-Gaussianity detection for our understanding of the physics of the early universe, it is important to employ alternative indicators in order to have further information about the Gaussianity features of CMB that may be helpful for identifying their origins. In this way, a considerable effort has recently gone into the design of non-Gaussianity indicators, and in their application in the search for deviation from Gaussianity in the CMB data. Recently we have proposed two new large-angle non-Gaussianity indicators which provide measures of the departure from Gaussianity on large angular scales. We have used these indicators to carry out analyses of Gaussianity of the single frequency bands and of the available foreground-reduced {\\it five-year} maps with and without the KQ75 mask. Here we extend and complement these studies by performing a new analysis of deviation from Gaussianity of the {\\it three-year} harmonic ILC (HILC) foreground-reduced full-sky and KQ75 masked maps obtained from WMAP data. We show that this full-sky foreground-reduced maps presents a significant deviation from Gaussianity, which is brought down to a level of consistency with Gaussianity when the KQ75 mask is employed.

A. Bernui; M. J. Reboucas

2010-04-11T23:59:59.000Z

36

Global, exact cosmic microwave background data analysis using Gibbs sampling  

SciTech Connect (OSTI)

We describe an efficient and exact method that enables global Bayesian analysis of cosmic microwave background (CMB) data. The method reveals the joint posterior density (or likelihood for flat priors) of the power spectrum C{sub l} and the CMB signal. Foregrounds and instrumental parameters can be simultaneously inferred from the data. The method allows the specification of a wide range of foreground priors. We explicitly show how to propagate the non-Gaussian dependency structure of the C{sub l} posterior through to the posterior density of the parameters. If desired, the analysis can be coupled to theoretical (cosmological) priors and can yield the posterior density of cosmological parameter estimates directly from the time-ordered data. The method does not hinge on special assumptions about the survey geometry or noise properties, etc., It is based on a Monte Carlo approach and hence parallelizes trivially. No trace or determinant evaluations are necessary. The feasibility of this approach rests on the ability to solve the systems of linear equations which arise. These are of the same size and computational complexity as the map-making equations. We describe a preconditioned conjugate gradient technique that solves this problem and demonstrate in a numerical example that the computational time required for each Monte Carlo sample scales as n{sub p}{sup 3/2} with the number of pixels n{sub p}. We use our method to analyze the data from the Differential Microwave Radiometer on the Cosmic Background Explorer and explore the non-Gaussian joint posterior density of the C{sub l} from the Differential Microwave Radiometer on the Cosmic Background Explorer in several projections.

Wandelt, Benjamin D. [Department of Physics, UIUC, 1110 W Green Street, Urbana, Illinois 61801 (United States); Department of Astronomy, UIUC, 1002 W Green Street, Urbana, Illinois 61801 (United States); Larson, David L.; Lakshminarayanan, Arun [Department of Physics, UIUC, 1110 W Green Street, Urbana, Illinois 61801 (United States)

2004-10-15T23:59:59.000Z

37

Extracting cosmic microwave background polarisation from satellite astrophysical maps  

E-Print Network [OSTI]

We present the application of the Fast Independent Component Analysis technique for blind component separation to polarised astrophysical emission. We study how the Cosmic Microwave Background (CMB) polarised signal, consisting of $E$ and $B$ modes, can be extracted from maps affected by substantial contamination from diffuse Galactic foregrounds and instrumental noise. We perform the analysis of all sky maps simulated accordingly to the nominal performances of the Low Frequency Instrument (LFI) aboard the Planck satellite; the sky signal is modeled as a superposition of CMB, generated by a Gaussian, nearly scale invariant cosmological perturbation spectrum, and the existing simulated polarisation templates of Galactic synchrotron. Our results indicate that the angular power spectrum of CMB $E$ modes can be recovered on all scales up to $\\ell\\simeq 1000$, corresponding to the fourth acoustic oscillation, while $B$ modes can be detected, up to their turnover at $\\ell\\simeq 100$ if cosmological tensor amplitude...

Baccigalupi, C; De Zotti, G; Smoot, G F; Burigana, C; Maino, D; Bedini, L; Salerno, E

2002-01-01T23:59:59.000Z

38

The nature of the Diffuse Gamma-Ray Background  

E-Print Network [OSTI]

We review the current understanding of the diffuse gamma-ray background (DGRB). The DGRB is what remains of the total measured gamma-ray emission after the subtraction of the resolved sources and of the diffuse Galactic foregrounds. It is interpreted as the cumulative emission of sources that are not bright enough to be detected individually. Yet, its exact composition remains unveiled. Well-established astrophysical source populations (e.g. blazars, misaligned AGNs, star-forming galaxies and millisecond pulsars) all represent guaranteed contributors to the DGRB. More exotic scenarios, such as dark matter annihilation or decay, may contribute as well. In this review, we describe how these components have been modeled in the literature and how the DGRB can be used to provide valuable information on each of them. We summarize the observational information currently available on the DGRB, paying particular attention to the most recent measurement of its intensity energy spectrum by the Fermi LAT Collaboration. W...

Fornasa, Mattia

2015-01-01T23:59:59.000Z

39

Swift detection of all previously undetected blazars in a micro-wave flux-limited sample of WMAP foreground sources  

E-Print Network [OSTI]

Almost the totality of the bright foreground sources in the WMAP CMB maps are blazars, a class of sources that show usually also X-ray emission. However, 23 objects in a flux-limited sample of 140 blazars of the WMAP catalog (first year) were never reported before as X-ray sources. We present here the results of 41 Swift observations which led to the detection of all these 23 blazars in the 0.3-10 keV band. We conclude that all micro-wave selected blazars are X-ray emitters and that the distribution of the micro-wave to X-ray spectral slope $\\alpha_{mu x}$ of LBL blazars is very narrow, confirming that the X-ray flux of most blazars is a very good estimator of their micro-wave emission. The X-ray spectral shape of all the objects that were observed long enough to allow spectral analysis is flat and consistent with inverse Compton emission within the commonly accepted view where the radiation from blazars is emitted in a Sychrotron-Inverse-Compton scenario. We predict that all blazars and most radio galaxies above the sensitivity limit of the WMAP and of the Planck CMB missions are X-ray sources detectable by the present generation of X-ray satellites. An hypothetical all-sky soft X-ray survey with sensitivity of approximately $10^{-15}$ erg/s would be crucial to locate and remove over 100,000 blazars from CMB temperature and polarization maps and therefore accurately clean the primordial CMB signal from the largest population of extragalactic foreground contaminants.

P. Giommi; M. Capalbi; E. Cavazzuti; S. Colafrancesco; A. Cucchiara; A. Falcone; J. Kennea; R. Nesci; M. Perri; G. Tagliaferri; A. Tramacere; G. Tosti; A. J. Blustin; G. Branduardi-Raymont; D. N. Burrows; G. Chincarini; A. J. Dean; N. Gehrels; H. Krimm; F. Marshall; A. M. Parsons; B. Zhang

2007-03-07T23:59:59.000Z

40

Carbon monoxide line emission as a CMB foreground: tomography of the star-forming universe with different spectral resolutions  

E-Print Network [OSTI]

The rotational lines of carbon monoxide and the fine structure lines of CII and of the most abundant metals, emitted during the epoch of enhanced star formation in the universe, are redshifted in the frequency channels where the present-day and future CMB experiments are sensitive. We estimate the contribution to the CMB angular power spectrum by the emission in such lines in merging star-forming galaxies. We used the Lacey-Cole approach to characterize the distribution of the merging halos, together with a parametrization for the star formation rate in each of them. Using observational data from a sample of local, low-redshift, and high-redshift objects, we calibrated the luminosity in each line as a function of the star formation rate. We show that the correlation term arising from CO line emission is a significant source of foreground for CMB in a broad range of frequencies (in particular in the 20-60 GHz band) and for 1000foreground sources and from the primary fluctuations themselves, since these show no significant dependence on the spectral resolution. We propose to perform observations with varying spectral bandwidths as a new tool to construct a tomography of the universe, by probing different redshift slices with varying thickness. (abridged)

Mattia Righi; Carlos Hernandez-Monteagudo; Rashid Sunyaev

2008-07-24T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): A SOUNDING ROCKET PAYLOAD TO STUDY THE NEAR INFRARED EXTRAGALACTIC BACKGROUND LIGHT  

SciTech Connect (OSTI)

The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

Zemcov, M.; Bock, J.; Hristov, V.; Levenson, L. R.; Mason, P. [Department of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Arai, T.; Matsumoto, T.; Matsuura, S.; Tsumura, K.; Wada, T. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Battle, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Cooray, A. [Center for Cosmology, University of California, Irvine, Irvine, CA 92697 (United States); Keating, B.; Renbarger, T. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H.; Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Sullivan, I. [Department of Physics, The University of Washington, Seattle, WA 98195 (United States); Suzuki, K., E-mail: zemcov@caltech.edu [Instrument Development Group of Technical Center, Nagoya University, Nagoya, Aichi 464-8602 (Japan)

2013-08-15T23:59:59.000Z

42

The Cosmic Background Radiation  

E-Print Network [OSTI]

We summarise the current status of cosmic microwave background spectrum and anisotropy measurements, and their theoretical interpretation. This is the update of the mini-review for the 1997 web-version of the Review of Particle Properties.

George Smoot; Douglas Scott

1997-11-08T23:59:59.000Z

43

TACMB-1: The Theory of Anisotropies in the Cosmic Microwave Background (Bibliographic Resource Letter)  

E-Print Network [OSTI]

This Resource Letter provides a guide to the literature on the theory of anisotropies in the cosmic microwave background. Journal articles, web pages, and books are cited for the following topics: discovery, cosmological origin, early work, recombination, general CMB anisotropy references, primary CMB anisotropies (numerical, analytical work), secondary effects, Sunyaev-Zel'dovich effect(s), lensing, reionization, polarization, gravity waves, defects, topology, origin of fluctuations, development of fluctuations, inflation and other ties to particle physics, parameter estimation, recent constraints, web resources, foregrounds, observations and observational issues, and gaussianity.

Martin White; J. D. Cohn

2002-03-07T23:59:59.000Z

44

EBSD Images Theoretical Background  

E-Print Network [OSTI]

Motivation EBSD Images Theoretical Background Defects in the Weld Grain Growth Low Speed Welding High Speed Welding Conclusion Heat-Affected Zone Observations Welding Experiments The low density in the transportation industries. Reproducibility and the low cost make welding a major large scale assembly process

Candea, George

45

Local microwave background radiation  

E-Print Network [OSTI]

An inquiry on a possible local origin for the Microwave Background Radiation is made. Thermal MBR photons are contained in a system called {\\it magnetic bottle} which is due to Earth magnetic field and solar wind particles, mostly electrons. Observational tests are anticipated.

Domingos Soares

2014-11-13T23:59:59.000Z

46

David Smith Academic background  

E-Print Network [OSTI]

David Smith Academic background Ph.D. in Mathematics (Algebra), Université de Sherbrooke, Canada project program (I. Assem, F. Bergeron, C. Reutenauer, D. Smith) $132,000 ($44,000 per year for 3 years. Schiffler and D. Smith, Friezes, strings and cluster variables, to appear in Glasgow Mathematcal Journal. 2

47

The {ital COBE} Diffuse Infrared Background Experiment Search for the Cosmic Infrared Background. I. Limits and Detections  

SciTech Connect (OSTI)

The Diffuse Infrared Background Experiment (DIRBE) on the Cosmic Background Explorer ({ital COBE}) spacecraft was designed primarily to conduct a systematic search for an isotropic cosmic infrared background (CIB) in 10 photometric bands from 1.25 to 240 {mu}m. The results of that search are presented here. Conservative limits on the CIB are obtained from the minimum observed brightness in all-sky maps at each wavelength, with the faintest limits in the DIRBE spectral range being at 3.5 {mu}m ({nu}{ital I}{sub {nu}} {lt} 64 nW m{sup {minus}2} sr{sup {minus}1}, 95{percent} confidence level) and at 240 {mu}m ({nu}{ital I}{sub {nu}} {lt} 28 nW m{sup {minus}2} sr{sup {minus}1}, 95{percent} confidence level). The bright foregrounds from interplanetary dust scattering and emission, stars, and interstellar dust emission are the principal impediments to the DIRBE measurements of the CIB. These foregrounds have been modeled and removed from the sky maps. Assessment of the random and systematic uncertainties in the residuals and tests for isotropy show that only the 140 and 240 {mu}m data provide candidate detections of the CIB. The residuals and their uncertainties provide CIB upper limits more restrictive than the dark sky limits at wavelengths from 1.25 to 100 {mu}m. No plausible solar system or Galactic source of the observed 140 and 240 {mu}m residuals can be identified, leading to the conclusion that the CIB has been detected at levels of {nu}{ital I}{sub {nu}} = 25 {plus_minus} 7 and 14 {plus_minus} 3 nW m{sup {minus}2} sr{sup {minus}1} at 140 and 240 {mu}m, respectively. The integrated energy from 140 to 240 {mu}m, 10.3 nW m{sup {minus}2} sr{sup {minus}1}, is about twice the integrated optical light from the galaxies in the Hubble Deep Field, suggesting that star formation might have been heavily enshrouded by dust at high redshift. The detections and upper limits reported here provide new constraints on models of the history of energy-releasing processes and dust production since the decoupling of the cosmic microwave background from matter. {copyright} {ital {copyright} 1998.} {ital The American Astronomical Society}

Hauser, M.G. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)] [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Arendt, R.G. [Raytheon STX, Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Raytheon STX, Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelsall, T.; Dwek, E. [Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Odegard, N.; Weiland, J.L.; Freudenreich, H.T. [Raytheon STX, Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Raytheon STX, Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Reach, W.T. [California Institute of Technology, IPAC/JPL, MS 100-22, Pasadena, CA 91125 (United States)] [California Institute of Technology, IPAC/JPL, MS 100-22, Pasadena, CA 91125 (United States); Silverberg, R.F.; Moseley, S.H. [Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Pei, Y.C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)] [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lubin, P. [Physics Department, University of California at Santa Barbara, Santa Barbara, CA 93106 (United States)] [Physics Department, University of California at Santa Barbara, Santa Barbara, CA 93106 (United States); Mather, J.C.; Shafer, R.A. [Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Code 685, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Smoot, G.F. [Lawrence Berkeley Laboratory, Space Sciences Laboratory, Department of Physics, UC Berkeley, CA 94720 (United States)] [Lawrence Berkeley Laboratory, Space Sciences Laboratory, Department of Physics, UC Berkeley, CA 94720 (United States); Weiss, R. [Massachusetts Institute of Technology, Room 20F-001, Department of Physics, Cambridge, MA 02139 (United States)] [Massachusetts Institute of Technology, Room 20F-001, Department of Physics, Cambridge, MA 02139 (United States); Wilkinson, D.T. [Princeton University, Department of Physics, Jadwin Hall, Box 708, Princeton, NJ 08544 (United States)] [Princeton University, Department of Physics, Jadwin Hall, Box 708, Princeton, NJ 08544 (United States); Wright, E.L. [UCLA, Astronomy Department, Los Angeles, CA 90024-1562 (United States)] [UCLA, Astronomy Department, Los Angeles, CA 90024-1562 (United States)

1998-11-01T23:59:59.000Z

48

ARM - Methane Background Information  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearchWarmingMethane Background Information Outreach Home Room News

49

Swift detection of all previously undetected blazars in a micro-wave flux-limited sample of WMAP foreground sources  

E-Print Network [OSTI]

Almost the totality of the bright foreground sources in the WMAP CMB maps are blazars, a class of sources that show usually also X-ray emission. However, 23 objects in a flux-limited sample of 140 blazars of the WMAP catalog (first year) were never reported before as X-ray sources. We present here the results of 41 Swift observations which led to the detection of all these 23 blazars in the 0.3-10 keV band. We conclude that all micro-wave selected blazars are X-ray emitters and that the distribution of the micro-wave to X-ray spectral slope $\\alpha_{mu x}$ of LBL blazars is very narrow, confirming that the X-ray flux of most blazars is a very good estimator of their micro-wave emission. The X-ray spectral shape of all the objects that were observed long enough to allow spectral analysis is flat and consistent with inverse Compton emission within the commonly accepted view where the radiation from blazars is emitted in a Sychrotron-Inverse-Compton scenario. We predict that all blazars and most radio galaxies a...

Giommi, P; Cavazzuti, E; Colafrancesco, S; Cucchiara, A; Falcone, A; Kennea, J; Nesci, R; Perri, M; Tagliaferri, G; Tramacere, A; Tosti, G; Blustin, A J; Branduardi-Raymont, G; Burrows, D N; Chincarini, G; Dean, A J; Gehrels, N; Krimm, H; Marshall, F; Parsons, A M; Zhang, B

2007-01-01T23:59:59.000Z

50

NEARBY PLANETARY SYSTEMS AS LENSES DURING PREDICTED CLOSE PASSAGES TO BACKGROUND STARS  

SciTech Connect (OSTI)

The Einstein rings and proper motions of nearby stars tend to be large. Thus, every year some foreground stars within a few hundred parsecs of Earth induce gravitational lensing events in background stars. In some of these cases, the events may exhibit evidence of planets orbiting the nearby star. In fact, planets can even be discovered during relatively distant passages. Here, we study the lensing signatures associated with planets orbiting nearby high-proper-motion stars. We find the following. (1) Wide-orbit planets can be detected for all distances of closest approach between the foreground and background stars, potentially producing independent events long before and/or after the closest approach. (2) Close-orbit planets can be detected for intermediate distances of closest approach, producing quasiperiodic signatures that may occur days or weeks before and after the stellar-lens event. (3) Planets in the so-called zone for resonant lensing can significantly increase the magnification when the distance of closest approach is small, making the stellar-lens event easier to detect, while simultaneously providing evidence for planets. Because approaches close enough to allow planets to be detected can be predicted, we can plan observing strategies to take advantage of the theoretical framework built in this paper, which describes the sequence of expected effects in terms of a sequence of detection regimes.

Di Stefano, Rosanne; Matthews, James [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lepine, Sebastien [Department of Astrophysics, Division of Physical Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)

2013-07-10T23:59:59.000Z

51

LTS Background - Hanford Site  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs space control News & EventsModelingBackground

52

Non-thermal Cosmic Backgrounds from Blazars: the contribution to the CMB, X-ray and gamma-ray Backgrounds  

E-Print Network [OSTI]

We present a new assessment of the contribution of Blazars to the extragalactic background radiation across the e.m. spectrum. Our calculations rely on deep Blazar radio counts that we derived combining several multifrequency surveys. The integrated Blazar emission yields a broad-band non-thermal background that in some parts of the e.m. spectrum dominates the extragalactic brightness. Blazars are the main point-like contributors to the CMB. Their integrated emission causes an apparent T increase of 5-50 muK in the 50-250 GHz range. The CMB fluctuation spectrum is sensibly contaminated at l>300, for a Poissonian source distribution, or at lower l values if spatial clustering is present. We estimate that well over 100,000 Blazars will produce a significant signal in the PLANCK CMB anisotropy maps. Because of the microwave-Xray flux correlation, these sources are expected to have flux > a few 10^{-15} erg/s in the soft X-ray band. Thus, a large fraction of the foreground sources in CMB anisotropy maps could be ...

Giommi, P; Cavazzuti, E; Perri, M; Pittori, C

2006-01-01T23:59:59.000Z

53

Cosmic Microwave Background Polarization  

E-Print Network [OSTI]

Cosmic microwave background (CMB) anisotropy is our richest source of cosmological information; the standard cosmological model was largely established thanks to study of the temperature anisotropies. By the end of the decade, the Planck satellite will close this important chapter and move us deeper into the new frontier of polarization measurements. Numerous ground--based and balloon--borne experiments are already forging into this new territory. Besides providing new and independent information on the primordial density perturbations and cosmological parameters, polarization measurements offer the potential to detect primordial gravity waves, constrain dark energy and measure the neutrino mass scale. A vigorous experimental program is underway worldwide and heading towards a new satellite mission dedicated to CMB polarization.

James G. Bartlett

2006-04-18T23:59:59.000Z

54

Non-thermal Cosmic Backgrounds from Blazars: the contribution to the CMB, X-ray and gamma-ray Backgrounds  

E-Print Network [OSTI]

We present a new assessment of the contribution of Blazars to the extragalactic background radiation across the e.m. spectrum. Our calculations rely on deep Blazar radio counts that we derived combining several multifrequency surveys. The integrated Blazar emission yields a broad-band non-thermal background that in some parts of the e.m. spectrum dominates the extragalactic brightness. Blazars are the main point-like contributors to the CMB. Their integrated emission causes an apparent T increase of 5-50 muK in the 50-250 GHz range. The CMB fluctuation spectrum is sensibly contaminated at l>300, for a Poissonian source distribution, or at lower l values if spatial clustering is present. We estimate that well over 100,000 Blazars will produce a significant signal in the PLANCK CMB anisotropy maps. Because of the microwave-Xray flux correlation, these sources are expected to have flux > a few 10^{-15} erg/s in the soft X-ray band. Thus, a large fraction of the foreground sources in CMB anisotropy maps could be identified and removed using a multi frequency approach, provided that a sufficiently deep all sky X-ray survey will be available. We further show that Blazars are a major constituent of all high-E extragalactic backgrounds. Their contribution is 11-12% at X-ray frequencies and possibly 100% in the 0.5-50 MeV band. At E>100 MeV, the Blazar collective emission, obtained extrapolating their integrated micro-wave flux to the gamma-ray band using the SED of EGRET detected sources, over-predicts the extragalactic background by a large factor, implying that Blazars not only dominate the gamma-ray sky but also that their average duty cycle at these frequencies must be rather low. We also find that Blazars of the HBL type may produce a significant amount of flux at TeV energies.

P. Giommi; S. Colafrancesco; E. Cavazzuti; M. Perri; C. Pittori

2005-08-01T23:59:59.000Z

55

Extracting cosmic microwave background polarisation from satellite astrophysical maps  

E-Print Network [OSTI]

We present the application of the Fast Independent Component Analysis ({\\ica}) technique for blind component separation to polarized astrophysical emission. We study how the Cosmic Microwave Background (CMB) polarized signal, consisting of $E$ and $B$ modes, can be extracted from maps affected by substantial contamination from diffuse Galactic foreground emission and instrumental noise. {We implement Monte Carlo chains varying the CMB and noise realizations in order to asses the average capabilities of the algorithm and their variance.} We perform the analysis of all sky maps simulated according to the {\\sc Planck} satellite capabilities, modelling the sky signal as a superposition of the CMB and of the existing simulated polarization templates of Galactic synchrotron. Our results indicate that the angular power spectrum of CMB $E$-mode can be recovered on all scales up to $\\ell\\simeq 1000$, corresponding to the fourth acoustic oscillation, while the $B$-mode power spectrum can be detected, up to its turnover at $\\ell\\simeq 100$, if the ratio of tensor to scalar contributions to the temperature quadrupole exceeds 30%. The power spectrum of the cross correlation between total intensity and polarization, $TE$, can be recovered up to $\\ell\\simeq 1200$, corresponding to the seventh $TE$ acoustic oscillation.

C. Baccigalupi; F. Perrotta; G. De Zotti; G. F. Smoot; C. Burigana; D. Maino; L. Bedini; E. Salerno

2004-07-12T23:59:59.000Z

56

Extracting cosmic microwave background polarization from satelliteastrophysical maps  

SciTech Connect (OSTI)

We present the application of the fast independent component analysis (FASTICA) technique for blind component separation to polarized astrophysical emission. We study how the cosmic microwave background (CMB) polarized signal, consisting of E and B modes, can be extracted from maps affected by substantial contamination from diffuse Galactic foreground emission and instrumental noise. We implement Monte Carlo chains varying the CMB and noise realizations in order to assess the average capabilities of the algorithm and their variance. We perform the analysis of all-sky maps simulated according to the Planck satellite capabilities, modeling the sky signal as a superposition of the CMB and of the existing simulated polarization templates of Galactic synchrotron. Our results indicate that the angular power spectrum of CMB E mode can be recovered on all scales up to lsimilar or equal to 1000, corresponding to the fourth acoustic oscillation, while the B-mode power spectrum can be detected, up to its turnover at lsimilar or equal to 100, if the ratio of tensor to scalar contributions to the temperature quadrupole exceeds 30 per cent. The power spectrum of the cross-correlation between total intensity and polarization, TE, can be recovered up to lsimilar or equal to 1200, corresponding to the seventh TE acoustic oscillation.

Baccigalpi, C.; Perrotta, F.; Zotti, G.D.; Smoot, G.F.; Burigana,C.; Maino, D.; Bedini, L.; Salerno, E.

2004-05-02T23:59:59.000Z

57

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

This concern is based on PTPC's interpretation of section 3.2 of BPA's Regional Dialogue Load Following Power Sales Agreement (Power Sales Agreement) template: 3.2 Take or Pay...

58

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

maintenance personnel, and film crews use small, portable lighting systems known as "mobile lighting." Traditionally, mobile lighting units are powered by diesel fuel generators...

59

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and the Bureau of Reclamation signed 10-year agreements - known as the Columbia Basin Fish Accords - with four Northwest tribes and two states on May 2, 2008. These historic...

60

Background:  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

files in future will now work correctly with that setting. (back to TOC) Importing the SSL Certificate in MSIE7 on Windows Vista Connecting to a Secure Socket Layer (SSL) enabled...

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

solutions in the area to meet its space needs and increase employee efficiency and productivity For the past 10 years, BPA has provided work space for area employees through a...

62

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

operations through another supplier if BPA was unable to supply Alcoa's Intalco smelter. In such circumstances, the demand shift would not materialize because the Intalco...

63

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Administration, January 14, 2011 Figure 2 - Natural Gas Rig Count U.S. Natural Gas Rotary Rigs in Operation (Count) 0 400 800 1200 1600 2000 J a n - 0 7 M a r - 0 7 M a y -...

64

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

V. RESPONSE TO COMMENTS: SPECIFIC CONTRACT ISSUES ... 14 a. Whether the ten year term of the Agreement is reasonable and consistent with sound business...

65

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P T E M0

66

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P T E M0Tech

67

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P T E

68

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P T

69

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P TBPA, the

70

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P TBPA,

71

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P

72

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE P

73

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBERE PAGENCY

74

Background  

Office of Scientific and Technical Information (OSTI)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinan antagonist Journal Article: Crystal structureComposite JC-118794ArgonneAnalysing the EffectEnergy Star

75

Background:  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to someone6 M. Babzien, I. Ben-Zvi, P. Study ofJ U LY 2 9

76

Background  

Office of Legacy Management (LM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou$0.C. 20545 OCTTO:March_

77

Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Renewable energy sources are critical to the nation's future, and hydrogen-powered fuel cells offer an attractive alternative to current technologies. However, fuel cell...

78

Aluminum as a source of background in low background experiments  

E-Print Network [OSTI]

Neutrinoless double beta decay would be a key to understanding the nature of neutrino masses. The next generation of High Purity Germanium experiments will have to be operated with a background rate of better than 10^-5 counts/(kg y keV) in the region of interest around the Q value of the decay. Therefore, so far irrelevant sources of background have to be considered. The metalization of the surface of germanium detectors is in general done with aluminum. The background from the decays of 22Na, 26Al, 226Ra and 228Th introduced by this metalization is discussed. It is shown that only a special selection of aluminum can keep these background contributions acceptable.

B. Majorovits; I. Abt; M. Laubenstein; O. Volynets

2011-05-18T23:59:59.000Z

79

Measurements of the spectral energy distribution of the cosmic infrared background  

E-Print Network [OSTI]

The extragalactic background light (EBL) is the relic emission of all processes of structure formation in the Universe. About half of this background, called the Cosmic Infrared Background (CIB) is emitted in the 8-1000 microns range, and peaks around 150 microns. It is due to the dust reemission from star formation processes and AGN emission. The CIB spectral energy distribution (SED) constraints the models of star formation in the Universe. It is also useful to compute the opacity of the Universe to the TeV photons. We present the different types of measurements of the CIB and discuss their strengths and weaknesses. 1. The absolute SED was measured by COBE, and by other experiments. These measurements are limited by the accuracy of the component separation, i.e. the foreground subtraction. 2. Robust lower limits are determined from the extragalactic number counts of infrared galaxies. These lower limits are very stringent up to 100 microns. At larger wavelengths, the rather low angular resolution of the ins...

Bthermin, Matthieu

2011-01-01T23:59:59.000Z

80

Observations of the Isotropic Diffuse Gamma-ray Background with the EGRET Telescope  

E-Print Network [OSTI]

An Isotropic Diffuse Gamma-Ray Background (IDGRB) in the spectral range 30-10,000 MeV was first reported in the early 1970's using measurements made by the SAS-2 instrument. Data recorded by the Energetic Gamma Ray Experiment Telescope (EGRET) on board the Compton Gamma Ray Observatory (CGRO) over the last 4 years are analysed in order to extract the best measurement yet made of the IDGRB. Extensive analysis of the EGRET instrumental background is presented in order to demonstrate that an uncontaminated data set can be extracted from the EGRET data. A model of the high latitude galactic diffuse foreground emission is presented and the existence of an IDGRB is confirmed. Spatial and spectral analysis of this background is presented. In addition, point source analysis at high galactic latitudes is performed to reveal the existence of a population of extragalactic sources. The characteristics of this population are examined and models of its flux distribution are reported. The question of whether the IDGRB is composed of unresolved point sources is addressed using fluctuation analysis. Finally, possible future directions for gamma ray astronomy are examined through simulations of a future gamma ray telescope: the Gamma-ray Large Area Space Telescope (GLAST). The GLAST baseline design is described and its scientific performance is evaluated. The ability of this telescope to detect 1,000-10,000 new extragalactic sources is demonstrated and the likely impact on the study of the IDGRB is considered.

T. D. Willis

2002-01-30T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Internal and External Radioactive Backgrounds  

E-Print Network [OSTI]

Chapter 3 Internal and External Radioactive Backgrounds New physics is often discovered by pushing energies. With the current large mixing angle-MSW oscillation parameters, Borexino expects to observe 0.35 neutrino events per day per ton from 7Be in the energy window. Because there are so few events

82

REFERENCE AND BACKGROUND CHECK PROCESS  

E-Print Network [OSTI]

REFERENCE AND BACKGROUND CHECK PROCESS Workforce Planning | 408-924-2250 classcomp process. Workforce Planning will arrange this directly with the finalist(s) once the hiring manager has provided the finalist(s) name(s) to Workforce Planning. An exception to this process is for any candidates

Su, Xiao

83

BEDES Background | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in Review: Top Five EERE BlogAttachmentFlash2011-21 AuditInsulatedEnergyBackground BEDES

84

Gauging the cosmic microwave background  

E-Print Network [OSTI]

We provide a new derivation of the anisotropies of the cosmic microwave background (CMB), and find an exact expression that can be readily expanded perturbatively. Close attention is paid to gauge issues, with the motivation to examine the effect of super-Hubble modes on the CMB. We calculate a transfer function that encodes the behaviour of the dipole, and examine its long-wavelength behaviour. We show that contributions to the dipole from adiabatic super-Hubble modes are strongly suppressed, even in the presence of a cosmological constant, contrary to claims in the literature. We also introduce a naturally defined CMB monopole, which exhibits closely analogous long-wavelength behaviour. We discuss the geometrical origin of this super-Hubble suppression, pointing out that it is a simple reflection of adiabaticity, and hence argue that it will occur regardless of the matter content.

J. P. Zibin; Douglas Scott

2008-12-21T23:59:59.000Z

85

Background canceling surface alpha detector  

DOE Patents [OSTI]

A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs.

MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

1996-06-11T23:59:59.000Z

86

Low Background Counting At SNOLAB  

SciTech Connect (OSTI)

It is a continuous and ongoing effort to maintain radioactivity in materials and in the environment surrounding most underground experiments at very low levels. These low levels are required so that experiments can achieve the required detection sensitivities for the detection of low-energy neutrinos, searches for dark matter and neutrinoless double-beta decay. SNOLAB has several facilities which are used to determine these low background levels in the materials and the underground environment. This proceedings will describe the SNOLAB High Purity Germanium Detector which has been in continuous use for the past five years and give results of many of the items that have been counted over that period. Brief descriptions of SNOLAB's alpha-beta and electrostatic counters will be given, and the radon levels at SNOLAB will be discussed.

Lawson, Ian; Cleveland, Bruce [SNOLAB, 1039 Regional Rd 24, Lively, ON P3Y 1N2 (Canada)

2011-04-27T23:59:59.000Z

87

Low background aspects of GERDA  

SciTech Connect (OSTI)

The GERDA experiment operates bare Germanium diodes enriched in {sup 76}Ge in an environment of pure liquid argon to search for neutrinoless double beta decay. A very low radioactive background is essential for the success of the experiment. We present here the research done in order to remove radio-impurities coming from the liquid argon, the stainless steel cryostat and the front-end electronics. We found that liquid argon can be purified efficiently from {sup 222}Rn. The main source of {sup 222}Rn in GERDA is the cryostat which emanates about 55 mBq. A thin copper shroud in the center of the cryostat was implemented to prevent radon from approaching the diodes. Gamma ray screening of radio-pure components for front-end electronics resulted in the development of a pre-amplifier with a total activity of less than 1 mBq {sup 228}Th.

Simgen, Hardy [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

2011-04-27T23:59:59.000Z

88

Are you sure that the anisotropies in the microwave background radiation are really cosmological rather than purely Galactic in origin?  

E-Print Network [OSTI]

New calculations of the Galactic contamination over microwave background radiation anisotropies are carried out. On one hand, when a frequency-dependent contrast of molecular clouds with respect to the Galactic background of the diffuse interstellar medium is taken into account, the anisotropic amplitude produced by Galactic dust is increased with respect to previous calculations and this is of the same order as that of the data from the observations. On the other hand, if we take into account rotational dust emission, for instance, a frequency independence of anisotropies in the microwave range may be obtained. This leads to the possibility that under some particular, but not impossible, conditions all the microwave background radiation anisotropies may be due to Galactic foregrounds rather than cosmological in origin. Moreover, a suspected coincidence between the typical angular sizes of the microwave background radiation anisotropies and those of nearby molecular clouds makes more plausible the hypothesis of a purely Galactic origin for these anisotropies. It is also argued that the correlation among structures at different frequencies, the comparison of the power spectrum at different frequencies and the galactic latitude dependence of the anisotropies are not yet proofs in favour of either a cosmological or Galactic origin.

M. Lopez-Corredoira

1999-05-01T23:59:59.000Z

89

DarkLight radiation backgrounds  

SciTech Connect (OSTI)

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-on, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW CW beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, field emission inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation.

Kalantarians, N. [Department of Physics, Hampton University, Hampton VA 23668 (United States); Collaboration: DarkLight Collaboration

2013-11-07T23:59:59.000Z

90

Gravitational clustering in Static and Expanding Backgrounds  

E-Print Network [OSTI]

A brief summary of several topics in the study of gravitational many body problem is given. The discussion covers both static backgrounds (applicable to astrophysical systems) as well as clustering in an expanding background (relevant for cosmology)

T. Padmanabhan

2003-08-28T23:59:59.000Z

91

Network Requirements Workshop - Documents and Background Materials  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Science Requirements Reviews Network Requirements Reviews Documents and Background Materials Science Engagement Move your data Programs & Workshops Science...

92

Solar Background Document 6 | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

6.pdf More Documents & Publications Solar Background Document 5 "Large Power Transformers and the U.S. Electric Grid" Report (June 2012) Dams and Energy Sectors...

93

Final Conservation Billing Credit Policy Supplement Background...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

December 17, 2014 Page 1 Final Conservation Billing Credit Policy Supplement Background and Need: This Conservation Billing Credit Policy Supplement describes how Bonneville Power...

94

Sources of the Radio Background Considered  

SciTech Connect (OSTI)

We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

2011-08-22T23:59:59.000Z

95

Stochastic Gravitational Wave Background from Exoplanets  

E-Print Network [OSTI]

Recent exoplanet surveys have predicted a very large population of planetary systems in our galaxy, more than one planet per star on the average, perhaps totalling about two hundred billion. These surveys, based on electro-magnetic observations, are limited to a very small neighbourhood of the solar system and the estimations rely on the observations of only a few thousand planets. On the other hand, orbital motions of planets around stars are expected to emit gravitational waves (GW), which could provide information about the planets not accessible to electro-magnetic astronomy. The cumulative effect of the planets, with periods ranging from few hours to several years, is expected to create a stochastic GW background (SGWB). We compute the characteristic GW strain of this background based on the observed distribution of planet parameters. We also show that the integrated extragalactic background is comparable or less than the galactic background at different frequencies. Our estimate shows that the net backg...

Ain, Anirban; Mitra, Sanjit

2015-01-01T23:59:59.000Z

96

Background and Motivation Biomass derived syngas contains  

E-Print Network [OSTI]

Background and Motivation Biomass derived syngas contains: CO, H2, small hydrocarbons, H2S prepared by SEA contain smaller metal particle sizes and have higher dispersion The quantity of reducible

Das, Suman

97

Environmental Permit Application Background Statement (Delaware)  

Broader source: Energy.gov [DOE]

The purpose of Chapter 79 of Delaware Title 7 is to ensure that the State has adequate information about the background of applicants or regulated parties for the purposes of processing permits and...

98

Low background counting techniques at SNOLAB  

SciTech Connect (OSTI)

Many of the experiments currently searching for dark matter, studying properties of neutrinos or searching for neutrinoless double beta decay require very low levels of radioactive backgrounds both in their own construction materials and in the surrounding environment. These low background levels are required so that the experiments can achieve the required sensitivities for their searches. SNOLAB has several facilities which are used to directly measure these radioactive backgrounds. This proceedings will describe SNOLAB's High Purity Germanium Detectors, one of which has been in continuous use for the past seven years measuring materials for many experiments in operation or under construction at SNOLAB. A description of the characterisation of SNOLAB's new germanium well detector will be presented. In addition, brief descriptions of SNOLAB's alpha-beta and electrostatic counters will be presented and a description of SNOLAB's future low background counting laboratory will be given.

Lawson, Ian; Cleveland, Bruce [SNOLAB, 1039 Regional Rd 24, Lively, ON P3Y 1N2 (Canada)] [SNOLAB, 1039 Regional Rd 24, Lively, ON P3Y 1N2 (Canada)

2013-08-08T23:59:59.000Z

99

Estimating radiological background using imaging spectroscopy  

SciTech Connect (OSTI)

Optical imaging spectroscopy is investigated as a method to estimate radiological background by spectral identification of soils, sediments, rocks, minerals and building materials derived from natural materials and assigning tabulated radiological emission values to these materials. Radiological airborne surveys are undertaken by local, state and federal agencies to identify the presence of radiological materials out of regulatory compliance. Detection performance in such surveys is determined by (among other factors) the uncertainty in the radiation background; increased knowledge of the expected radiation background will improve the ability to detect low-activity radiological materials. Radiological background due to naturally occurring radiological materials (NORM) can be estimated by reference to previous survey results, use of global 40K, 238U, and 232Th (KUT) values, reference to existing USGS radiation background maps, or by a moving average of the data as it is acquired. Each of these methods has its drawbacks: previous survey results may not include recent changes, the global average provides only a zero-order estimate, the USGS background radiation map resolutions are coarse and are accurate only to 1 km 25 km sampling intervals depending on locale, and a moving average may essentially low pass filter the data to obscure small changes in radiation counts. Imaging spectroscopy from airborne or spaceborne platforms can offer higher resolution identification of materials and background, as well as provide imaging context information. AVIRIS hyperspectral image data is analyzed using commercial exploitation software to determine the usefulness of imaging spectroscopy to identify qualitative radiological background emissions when compared to airborne radiological survey data.

Bernacki, Bruce E.; Schweppe, John E.; Stave, Sean C.; Jordan, David V.; Kulisek, Jonathan A.; Stewart, Trevor N.; Seifert, Carolyn E.

2014-06-13T23:59:59.000Z

100

Fractal generation of textures and backgrounds  

E-Print Network [OSTI]

FRACTAL GENERATION OF TEXTURES AND BACKGROUNDS A Thesis by KEVIN DUANE REUTER Subtnitted to the Oflice of Graduate Studies of Texas A&M University in partial fulfilhnent of the requirements for the degree of MASTER OF SCIENCE August 1999... Major Subject; Visualization Sciences FRACTAL GENERATION OF TEXTURES AND BACKGROUNDS A Thesis by KEVIN DUANE REUTER Submitted to Texas ARM University in partial fulfilhnent of the requirements for the degree of MASTER OF SCIENCE Approved...

Reuter, Kevin Duane

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Background Assay and Rejection in DRIFT  

E-Print Network [OSTI]

The DRIFT-IId dark matter detector is a m$^3$-scale low-pressure TPC with directional sensitivity to WIMP-induced nuclear recoils. Its primary backgrounds were due to alpha decays from contamination on the central cathode. Efforts to reduce these backgrounds led to replacing the 20 \\mu m wire central cathode with one constructed from 0.9 \\mu m aluminized mylar, which is almost totally transparent to alpha particles. Detailed modeling of the nature and origin of the remaining backgrounds led to an in-situ, ppt-sensitive assay of alpha decay backgrounds from the central cathode. This led to further improvements in the thin-film cathode resulting in over 2 orders of magnitude reduction in backgrounds compared to the wire cathode. Finally, the addition of O$_2$ to CS$_2$ gas was found to produce multiple species of electronegative charge carriers, providing a method to determine the absolute position of nuclear recoils and reject all known remaining backgrounds while retaining a high efficiency for nuclear recoil detection.

Jeff Brack; Ed Daw; Alexei Dorofeev; Anthony Ezeribe; Jean-Luc Gauvreau; Michael Gold; John Harton; Randy Lafler; Robert Lauer; Eric R. Lee; Dinesh Loomba; John Matthews; Eric H. Miller; Alissa Monte; Alex Murphy; Sean Paling; Nguyen Phan; Steve Sadler; Andrew Scarff; Daniel Snowden-Ifft; Neil Spooner; Sam Telfer; Daniel Walker; Matt Williams; Leonid Yuriev

2014-04-08T23:59:59.000Z

102

Cosmic microwave background constraints on dark energy dynamics: analysis beyond the power spectrum  

E-Print Network [OSTI]

We consider the distribution of the non-Gaussian signal induced by weak lensing on the primary total intensity cosmic microwave background (CMB) anisotropies. Our study focuses on the three point statistics exploiting an harmonic analysis based on the CMB bispectrum. By considering the three multipoles as independent variables, we reveal a complex structure of peaks and valleys determined by the re-projection of the primordial acoustic oscillations through the lensing mechanism. We study the dependence of this system on the expansion rate at the epoch in which the weak lensing power injection is relevant, probing the dark energy equation of state at redshift corresponding to the equivalence with matter or higher ($w_\\infty$). We evaluate the impact of the bispectrum observable on the CMB capability of constraining the dark energy dynamics. We perform a maximum likelihood analysis by varying the dark energy abundance, the present equation of state $w_0$ and $w_\\infty$. We show that the projection degeneracy affecting a pure power spectrum analysis in total intensity is broken if the bispectrum is taken into account. For a Planck-like experiment, assuming nominal performance, no foregrounds or systematics, and fixing all the parameters except $w_0$, $w_\\infty$ and the dark energy abundance, a percent and ten percent precision measure of $w_0$ and $w_\\infty$ is achievable from CMB data only. These results indicate that the detection of the weak lensing signal by the forthcoming CMB probes may be relevant to gain insight into the dark energy dynamics at the onset of cosmic acceleration.

Fabio Giovi; Carlo Baccigalupi; Francesca Perrotta

2005-05-18T23:59:59.000Z

103

FIRST SEASON QUIET OBSERVATIONS: MEASUREMENTS OF COSMIC MICROWAVE BACKGROUND POLARIZATION POWER SPECTRA AT 43 GHz IN THE MULTIPOLE RANGE 25 {<=} l {<=} 475  

SciTech Connect (OSTI)

The Q/U Imaging ExperimenT (QUIET) employs coherent receivers at 43 GHz and 94 GHz, operating on the Chajnantor plateau in the Atacama Desert in Chile, to measure the anisotropy in the polarization of the cosmic microwave background (CMB). QUIET primarily targets the B modes from primordial gravitational waves. The combination of these frequencies gives sensitivity to foreground contributions from diffuse Galactic synchrotron radiation. Between 2008 October and 2010 December, over 10,000 hr of data were collected, first with the 19 element 43 GHz array (3458 hr) and then with the 90 element 94 GHz array. Each array observes the same four fields, selected for low foregrounds, together covering Almost-Equal-To 1000 deg{sup 2}. This paper reports initial results from the 43 GHz receiver, which has an array sensitivity to CMB fluctuations of 69 {mu}K{radical}s. The data were extensively studied with a large suite of null tests before the power spectra, determined with two independent pipelines, were examined. Analysis choices, including data selection, were modified until the null tests passed. Cross-correlating maps with different telescope pointings is used to eliminate a bias. This paper reports the EE, BB, and EB power spectra in the multipole range l = 25-475. With the exception of the lowest multipole bin for one of the fields, where a polarized foreground, consistent with Galactic synchrotron radiation, is detected with 3{sigma} significance, the E-mode spectrum is consistent with the {Lambda}CDM model, confirming the only previous detection of the first acoustic peak. The B-mode spectrum is consistent with zero, leading to a measurement of the tensor-to-scalar ratio of r = 0.35{sup +1.06}{sub -0.87}. The combination of a new time-stream 'double-demodulation' technique, side-fed Dragonian optics, natural sky rotation, and frequent boresight rotation leads to the lowest level of systematic contamination in the B-mode power so far reported, below the level of r = 0.1.

Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A.; Smith, K. M. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States); Chinone, Y. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K.; Reeves, R. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Dumoulin, R. N.; Newburgh, L. B.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Monsalve, R.; Bustos, R. [Department of Physics, University of Miami, Coral Gables, FL 33146 (United States); Naess, S. K.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, N-0315 Oslo (Norway); Wehus, I. K. [Department of Physics, University of Oslo, N-0316 Oslo (Norway); Zuntz, J. A. [Department of Astrophysics, University of Oxford, Oxford OX1 3RH (United Kingdom); Bronfman, L. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Church, S. E. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Varian Physics Building, Stanford, CA 94305 (United States); Dickinson, C., E-mail: akito@kicp.uchicago.edu [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

2011-11-10T23:59:59.000Z

104

Background modeling for the GERDA experiment  

SciTech Connect (OSTI)

The neutrinoless double beta (0???) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0??? decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Q{sub ??} come from {sup 214}Bi, {sup 228}Th, {sup 42}K, {sup 60}Co and ? emitting isotopes in the {sup 226}Ra decay chain, with a fraction depending on the assumed source positions.

Becerici-Schmidt, N. [Max-Planck-Institut fr Physik, Mnchen (Germany)] [Max-Planck-Institut fr Physik, Mnchen (Germany); Collaboration: GERDA Collaboration

2013-08-08T23:59:59.000Z

105

Cosmological origin of anomalous radio background  

SciTech Connect (OSTI)

The ARCADE 2 collaboration has reported a significant excess in the isotropic radio background, whose homogeneity cannot be reconciled with clustered sources. This suggests a cosmological origin prior to structure formation. We investigate several potential mechanisms and show that injection of relativistic electrons through late decays of a metastable particle can give rise to the observed excess radio spectrum through synchrotron emission. However, constraints from the cosmic microwave background (CMB) anisotropy, on injection of charged particles and on the primordial magnetic field, present a challenge. The simplest scenario is with a ?>9 GeV particle decaying into e{sup +}e{sup ?} at a redshift of z ? 5, in a magnetic field of ? 5?G, which exceeds the CMB B-field constraints, unless the field was generated after decoupling. Decays into exotic millicharged particles can alleviate this tension, if they emit synchroton radiation in conjunction with a sufficiently large background magnetic field of a dark U(1)' gauge field.

Cline, James M. [Department of Physics, McGill University, 3600 Rue University, Montral, Qubec, H3A 2T8 Canada (Canada); Vincent, Aaron C., E-mail: jcline@physics.mcgill.ca, E-mail: vincent@ific.uv.es [Instituto de Fsica Corpuscular, Universitat de Valncia - CSIC, 46071, Valencia (Spain)

2013-02-01T23:59:59.000Z

106

Cosmic Microwave Background Tests of Inflation  

E-Print Network [OSTI]

Inflation provides a unified paradigm for understanding the isotropy of the cosmic microwave background (CMB), the flatness problem, and the origin of large-scale structure. Although the physics responsible for inflation is not yet well understood, slow-roll inflation generically makes several predictions: a flat Universe, primordial adiabatic density perturbations, and a stochastic gravity-wave background. Inflation further predicts specific relations between the amplitudes and shapes of the spectrum of density perturbations and gravity waves. There are now excellent prospects for testing precisely these predictions with forthcoming CMB temperature and polarization maps. Here I discuss these new CMB tests of inflation.

Marc Kamionkowski

1998-03-14T23:59:59.000Z

107

Background field method and nonrelativistic QED matching  

E-Print Network [OSTI]

We discuss the resolution of an inconsistency between lattice background field methods and nonrelativistic QED matching conditions. In particular, we show that lack of on-shell conditions in lattice QCD with time-dependent background fields generally requires that certain operators related by equations of motion should be retained in an effective field theory to correctly describe the behavior of Green's functions. The coefficients of such operators in a nonrelativistic hadronic theory are determined by performing a robust nonrelativistic expansion of QED for relativistic scalar and spin-half hadrons including nonminimal electromagnetic couplings. Provided that nonrelativistic QED is augmented with equation-of-motion operators, we find that the background field method can be reconciled with the nonrelativistic QED matching conditions without any inconsistency. We further investigate whether nonrelativistic QED can be employed in the analysis of lattice QCD correlation function in background fields, but we are confronted with difficulties. Instead, we argue that the most desirable approach is a hybrid one which relies on a relativistic hadronic theory with operators chosen based on their relevance in the nonrelativistic limit. Using this hybrid framework, we obtain practically useful forms of correlation functions for scalar and spin-half hadrons in uniform electric and magnetic fields.

Jong-Wan Lee; Brian C. Tiburzi

2014-11-15T23:59:59.000Z

108

Background Material Important Questions about Magnetism  

E-Print Network [OSTI]

Background Material Important Questions about Magnetism: 1) What is Magnetism?Magnetism is a force or repulsion due to charge is called the electric force. But what about magnetism, is there a fundamental property of some matter that makes things magnetic? The answer is: "sort of." Electric current

Mojzsis, Stephen J.

109

UCHC Lockout/Tagout Policy Background  

E-Print Network [OSTI]

UCHC Lockout/Tagout Policy (4/09) Background: This safety policy is applicable to all Health Center: Lockout will be utilized for equipment which is designed with a lockout capability. A valve that can be locked out with a chain is considered as having a lockout capability. Only the Office of Research Safety

Kim, Duck O.

110

CHAPTER 1 INTRODUCTION 1.1 Background  

E-Print Network [OSTI]

1 CHAPTER 1 INTRODUCTION 1.1 Background This thesis describes a multi-agent based architecture of the research and an outline plan for the rest of this thesis complete the chapter. 1.2 Software Project and monitor progress to check the development is on time and within budget. #12;3 1.3 Software Project

O'Connor, Rory

111

1 Introduction 1.1 Background  

E-Print Network [OSTI]

#12;#12;3 1 Introduction 1.1 Background Research method is a relevant topic to anybody performing. 1.2 Classical Research, Technology and Technology Research The term research is defined in several different ways. According to Merriam-Webster [1], research is "investigation or experimentation aimed

Stølen, Ketil

112

Cosmic Background Radiation Due to Photon Condensation  

E-Print Network [OSTI]

It is shown that a collection of photons with nearly the same frequency exhibits a Bose "condensation" type of phenomenon at about 3 degrees K corresponding to a peak intensity at a wave length of about 0.4cm. This could give a mechanism for the observed Cosmic Background Radiation, and also explain some curious features.

B. G. Sidharth

1998-06-10T23:59:59.000Z

113

Perturbations of supertube in KK monopole background  

E-Print Network [OSTI]

We study perturbations of supertube in KK monopole background, at both DBI and supergravity levels. We analyse both NS1-P as well as D0-F1 duality frames and study different profiles. This illuminates certain aspects of bound states of KK monopoles with supertubes.

Yogesh K. Srivastava

2006-11-29T23:59:59.000Z

114

Cosmic IR Backgrounds Ned Wright (UCLA)  

E-Print Network [OSTI]

Cosmic IR Backgrounds by Ned Wright (UCLA) http://www.astro.ucla.edu/~wright/intro.html See: · http://www.astro.ucla.edu/~wright/cosmolog.htm · http://www.astro.ucla.edu/~wright/DIRBE · http://www.astro.ucla.edu/~wright/CIBR · http

Wright, Edward L. "Ned"

115

2013 National Geothermal Student Competition Background  

E-Print Network [OSTI]

1 2013 National Geothermal Student Competition Background: The 2013 National Geothermal Student, is designed to advance the understanding of geothermal energy as a valued resource by promoting innovation to engage students in a collaborative exercise to develop a business plan for developing a geothermal

Carrington, Emily

116

Background Simulations for the International Linear Collider  

E-Print Network [OSTI]

on superconducting technology to collide bunches of electrons and positrons. The baseline configuration (about 31 km in a clean experimental environment with low backgrounds. The LHC will likely discover the Higgs boson accelerator directly. DESY FLC, 22603 Hamburg, Germany, adrian.vogel@desy.de 1 #12;Figure 1: Overall view

117

Foreign Energy Company Competitiveness: Background information  

SciTech Connect (OSTI)

This report provides background information to the report Energy Company Competitiveness: Little to Do With Subsidies (DOE 1994). The main body of this publication consists of data uncovered during the course of research on this DOE report. This data pertains to major government energy policies in each country studied. This report also provides a summary of the DOE report. In October 1993, the Office of Energy Intelligence, US Department of Energy (formerly the Office of Foreign Intelligence), requested that Pacific Northwest Laboratory prepare a report addressing policies and actions used by foreign governments to enhance the competitiveness of their energy firms. Pacific Northwest Laboratory prepared the report Energy Company Competitiveness Little to Do With Subsidies (DOE 1994), which provided the analysis requested by DOE. An appendix was also prepared, which provided extensive background documentation to the analysis. Because of the length of the appendix, Pacific Northwest Laboratory decided to publish this information separately, as contained in this report.

Weimar, M.R.; Freund, K.A.; Roop, J.M.

1994-10-01T23:59:59.000Z

118

Cosmic Microwave Background: Past, Future, and Present  

E-Print Network [OSTI]

I explain the origin and evolution of anisotropies in the Cosmic Microwave Background (CMB) and argue that upcoming experiments will measure cosmological and fundamental parameters very accurately. Most of the paper focuses on present data, which strongly suggest that the universe is flat. Several arguments are given to prove that present data sets are not contaminated by systematics. New techniques to compare different experiments visually are introduced. These are illustrated for two years of the MSAM and Python experiments.

Scott Dodelson

1999-12-22T23:59:59.000Z

119

Sideband Mixing in Intense Laser Backgrounds  

E-Print Network [OSTI]

The electron propagator in a laser background has been shown to be made up of a series of sideband poles. In this paper we study this decomposition by analysing the impact of the residual gauge freedom in the Volkov solution on the sidebands. We show that the gauge transformations do not alter the location of the poles. The identification of the propagator from the two-point function is maintained but we show that the sideband structures mix under residual gauge transformations.

Martin Lavelle; David McMullan

2014-07-04T23:59:59.000Z

120

A background free double beta decay experiment  

E-Print Network [OSTI]

We present a new detection scheme for rejecting backgrounds in neutrino less double beta decay experiments. It relies on the detection of Cherenkov light emitted by electrons in the MeV region. The momentum threshold is tuned to reach a good discrimination between background and good events. We consider many detector concepts and a range of target materials. The most promising is a high-pressure 136Xe emitter for which the required energy threshold is easily adjusted. Combination of this concept and a high pressure Time Projection Chamber could provide an optimal solution. A simple and low cost effective solution is to use the Spherical Proportional Counter that provides two delayed signals from ionization and Cherenkov light. In solid-state double beta decay emitters, because of their higher density, the considered process is out of energy range. An alternative solution could be the development of double decay emitters with lower density by using for instance the aerogel technique. It is surprising that a technology used for particle identification in high-energy physics becomes a powerful tool for rejecting backgrounds in such low-energy experiments.

Ioannis Giomataris

2010-12-20T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Higher-Order Gravitational Perturbations of the Cosmic Microwave Background  

E-Print Network [OSTI]

We study the behavior of light rays in perturbed Robertson-Walker cosmologies, calculating the redshift between an observer and the surface of last scattering to second order in the metric perturbation. At first order we recover the classic results of Sachs and Wolfe, and at second order we delineate the various new effects which appear; there is no {\\it a priori} guarantee that these effects are significantly smaller than those at first order, since there are large length scales in the problem which could lead to sizable prefactors. We find that second order terms of potential observational interest may be interpreted as transverse and longitudinal lensing by foreground density perturbations, and a correction to the integrated Sachs-Wolfe effect.

Ted Pyne; Sean M. Carroll

1995-12-07T23:59:59.000Z

122

Hanford Site background: Part 1, Soil background for nonradioactive analytes. Revision 1, Volume 1  

SciTech Connect (OSTI)

The determination of soil background is one of the most important activities supporting environmental restoration and waste management on the Hanford Site. Background compositions serve as the basis for identifying soil contamination, and also as a baseline in risk assessment processes used to determine soil cleanup and treatment levels. These uses of soil background require an understanding of the extent to which analytes of concern occur naturally in the soils. This report documents the results of sampling and analysis activities designed to characterize the composition of soil background at the Hanford Site, and to evaluate the feasibility for use as Sitewide background. The compositions of naturally occurring soils in the vadose Zone have been-determined for-nonradioactive inorganic and organic analytes and related physical properties. These results confirm that a Sitewide approach to the characterization of soil background is technically sound and is a viable alternative to the determination and use of numerous local or area backgrounds that yield inconsistent definitions of contamination. Sitewide soil background consists of several types of data and is appropriate for use in identifying contamination in all soils in the vadose zone on the Hanford Site. The natural concentrations of nearly every inorganic analyte extend to levels that exceed calculated health-based cleanup limits. The levels of most inorganic analytes, however, are well below these health-based limits. The highest measured background concentrations occur in three volumetrically minor soil types, the most important of which are topsoils adjacent to the Columbia River that are rich in organic carbon. No organic analyte levels above detection were found in any of the soil samples.

Not Available

1993-04-01T23:59:59.000Z

123

New physics from the Cosmic Microwave Background  

E-Print Network [OSTI]

I review the present status of the Cosmic Microwave Background, with some emphasis on the current and future implications for particle physics. Conclusions are: gravitational instability in a dark matter dominated universe grew today's structure; the Universe remained neutral until z<~50; the CMB power spectrum peaks at 150<~l<~350; the large-scale structure of spacetime appears to be simple; something like inflation is something like proven; we will learn a great deal about cosmology, astrophysics and particle physics from MAP and Planck.

Douglas Scott

1999-11-17T23:59:59.000Z

124

Superconducting Hair on Charged Black String Background  

E-Print Network [OSTI]

Behaviour of Dirac fermions in the background of a charged black string penetrated by an Abelian Higgs vortex is elaborated. One finds the evidence that the system under consideration can support fermion fields acting like a superconducting cosmic string in the sence that a nontrivial Dirac fermion field can be carried by the system in question. The case of nonextremal and extremal black string vortex systems were considered. The influence of electric and Higgs charge, the winding number and the fermion mass on the fermion localization near the black string event horizon was studied. It turned out that the extreme charged black string expelled fermion fields more violently comparing to the nonextremal one.

Lukasz Nakonieczny; Marek Rogatko

2012-01-25T23:59:59.000Z

125

A background free double beta decay experiment  

E-Print Network [OSTI]

We present a new detection scheme for rejecting backgrounds in neutrino less double beta decay experiments. It relies on the detection of Cherenkov light emitted by electrons in the MeV region. The momentum threshold is tuned to reach a good discrimination between background and good events. We consider many detector concepts and a range of target materials. The most promising is a high-pressure 136Xe emitter for which the required energy threshold is easily adjusted. Combination of this concept and a high pressure Time Projection Chamber could provide an optimal solution. A simple and low cost effective solution is to use the Spherical Proportional Counter that provides two delayed signals from ionization and Cherenkov light. In solid-state double beta decay emitters, because of their higher density, the considered process is out of energy range. An alternative solution could be the development of double decay emitters with lower density by using for instance the aerogel technique. It is surprising that a te...

Giomataris, Ioannis

2010-01-01T23:59:59.000Z

126

apm background radiation: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Extragalactic Background Radiation Astrophysics (arXiv) Summary: Attenuation of high--energy gamma rays by pair--production with UV, optical and IR background photons provides a...

127

Anisotropies in the Cosmic Microwave Background: Theory  

E-Print Network [OSTI]

Anisotropies in the Cosmic Microwave Background (CMB) contain a wealth of information about the past history of the universe and the present values of cosmological parameters. I ouline some of the theoretical advances of the last few years. In particular, I emphasize that for a wide class of cosmological models, theorists can accurately calculate the spectrum to better than a percent. The specturm of anisotropies today is directly related to the pattern of inhomogeneities present at the time of recombination. This recognition leads to a powerful argument that will enable us to distinguish inflationary models from other models of structure formation. If the inflationary models turn out to be correct, the free parameters in these models will be determined to unprecedented accuracy by the upcoming satellite missions.

Scott Dodelson

1997-02-14T23:59:59.000Z

128

The Cosmic Microwave Background and Particle Physics  

E-Print Network [OSTI]

In forthcoming years, connections between cosmology and particle physics will be made increasingly important with the advent of a new generation of cosmic microwave background (CMB) experiments. Here, we review a number of these links. Our primary focus is on new CMB tests of inflation. We explain how the inflationary predictions for the geometry of the Universe and primordial density perturbations will be tested by CMB temperature fluctuations, and how the gravitational waves predicted by inflation can be pursued with the CMB polarization. The CMB signatures of topological defects and primordial magnetic fields from cosmological phase transitions are also discussed. Furthermore, we review current and future CMB constraints on various types of dark matter (e.g. massive neutrinos, weakly interacting massive particles, axions, vacuum energy), decaying particles, the baryon asymmetry of the Universe, ultra-high-energy cosmic rays, exotic cosmological topologies, and other new physics.

Marc Kamionkowski; Arthur Kosowsky

1999-04-09T23:59:59.000Z

129

RPV stops bump off the background  

E-Print Network [OSTI]

We study the 8 TeV LHC reach on pair produced heavy flavored di-jet resonances. Motivated by theories of R-parity violation in supersymmetry we concentrate on a final state with two b-jets and two light jets. We exploit b-tagging to reject the background and discuss its importance at the trigger level to probe light stops. We present kinematical selections that can be used to isolate the signal as a bump in the mass distribution of the candidate resonances. We find that stops with R-parity violating couplings giving rise to fully hadronic final states can be observed in the current run of the LHC. Remarkably, the LHC can probe stop masses well within the range predicted by naturalness.

Roberto Franceschini; Riccardo Torre

2014-09-24T23:59:59.000Z

130

SECOND SEASON QUIET OBSERVATIONS: MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND POLARIZATION POWER SPECTRUM AT 95 GHz  

SciTech Connect (OSTI)

The Q/U Imaging ExperimenT (QUIET) has observed the cosmic microwave background (CMB) at 43 and 95 GHz. The 43 GHz results have been published in a previous paper, and here we report the measurement of CMB polarization power spectra using the 95 GHz data. This data set comprises 5337 hr of observations recorded by an array of 84 polarized coherent receivers with a total array sensitivity of 87 {mu}K{radical}s. Four low-foreground fields were observed, covering a total of {approx}1000 deg{sup 2} with an effective angular resolution of 12.'8, allowing for constraints on primordial gravitational waves and high signal-to-noise measurements of the E-modes across three acoustic peaks. The data reduction was performed using two independent analysis pipelines, one based on a pseudo-C {sub l} (PCL) cross-correlation approach, and the other on a maximum-likelihood (ML) approach. All data selection criteria and filters were modified until a predefined set of null tests had been satisfied before inspecting any non-null power spectrum. The results derived by the two pipelines are in good agreement. We characterize the EE, EB, and BB power spectra between l = 25 and 975 and find that the EE spectrum is consistent with {Lambda}CDM, while the BB power spectrum is consistent with zero. Based on these measurements, we constrain the tensor-to-scalar ratio to r = 1.1{sup +0.9} {sub -0.8} (r < 2.8 at 95% C.L.) as derived by the ML pipeline, and r = 1.2{sup +0.9} {sub -0.8} (r < 2.7 at 95% C.L.) as derived by the PCL pipeline. In one of the fields, we find a correlation with the dust component of the Planck Sky Model, though the corresponding excess power is small compared to statistical errors. Finally, we derive limits on all known systematic errors, and demonstrate that these correspond to a tensor-to-scalar ratio smaller than r = 0.01, the lowest level yet reported in the literature.

Araujo, D.; Dumoulin, R. N.; Newburgh, L. B.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Chinone, Y. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K.; Reeves, R. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Blvd M/C 249-17, Pasadena, CA 91125 (United States); Monsalve, R.; Bustos, R. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Naess, S. K.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Wehus, I. K. [Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Bronfman, L. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Church, S. E. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Varian Physics Building, 382 Via Pueblo Mall, Stanford, CA 94305 (United States); Dickinson, C. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Gaier, T., E-mail: ibuder@uchicago.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Collaboration: QUIET Collaboration; and others

2012-12-01T23:59:59.000Z

131

Schwarzschild black hole in dark energy background  

E-Print Network [OSTI]

In this paper we present an exact solution of Einstein's field equations describing the Schwarzschild black hole in dark energy background. It is also regarded as an embedded solution that the Schwarzschild black hole is embedded into the dark energy space producing Schwarzschild-dark energy black hole. It is found that the space-time geometry of Schwarzschild-dark energy solution is non-vacuum Petrov type $D$ in the classification of space-times. We study the energy conditions (like weak, strong and dominant conditions) for the energy-momentum tensor of the Schwarzschild-dark energy solution. We also find that the energy-momentum tensor of the Schwarzschild-dark energy solution violates the strong energy condition due to the negative pressure leading to a repulsive gravitational force of the matter field in the space-time. It is shown that the time-like vector field for an observer in the Schwarzschild-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity and the area of the horizons for the Schwarzschild-dark energy black hole.

Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh

2014-09-27T23:59:59.000Z

132

Statistics of Cosmic Microwave Background Polarization  

E-Print Network [OSTI]

We present a formalism for analyzing a full-sky temperature and polarization map of the cosmic microwave background. Temperature maps are analyzed by expanding over the set of spherical harmonics to give multipole moments of the two-point correlation function. Polarization, which is described by a second-rank tensor, can be treated analogously by expanding in the appropriate tensor spherical harmonics. We provide expressions for the complete set of temperature and polarization multipole moments for scalar and tensor metric perturbations. Four sets of multipole moments completely describe isotropic temperature and polarization correlations; for scalar metric perturbations one set is identically zero, giving the possibility of a clean determination of the vector and tensor contributions. The variance with which the multipole moments can be measured in idealized experiments is evaluated, including the effects of detector noise, sky coverage, and beam width. Finally, we construct coordinate-independent polarization two-point correlation functions, express them in terms of the multipole moments, and derive small-angle limits.

Marc Kamionkowski; Arthur Kosowsky; Albert Stebbins

1996-11-15T23:59:59.000Z

133

ISO and the Cosmic Infrared Background  

E-Print Network [OSTI]

ISO observed, for the first time to such a high sensitivity level, the mid- and far-infrared universe. A Number of deep surveys were performed to probe the cosmological evolution of galaxies. In this review, I discuss and summarize results of mid-infrared ISOCAM and far-infrared ISOPHOT surveys, and show how our vision of the extragalactic infrared universe has become more accurate. In particular, ISO allowed us to resolve into sources a significant fraction of the Cosmic Infrared Background (CIB) in the mid-infrared, and to probe a fainter population in the far-infrared with the detection of the CIB fluctuations. Together with other wavelength data sets, the nature of ISO galaxies is now in the process of being understood. I also show that the high quality of the ISO data put strong constraints on the scenarios of galaxy evolution. This induced a burst in the development of models, yielding to a more coherent picture of galaxy evolution. I finally emphasize the potential of the ISO data archive in the field of observational cosmology, and describe the next steps, in particular the forthcoming cosmological surveys to be carried out by SIRTF.

Herve Dole

2002-12-12T23:59:59.000Z

134

K-mouflage Cosmology: the Background Evolution  

E-Print Network [OSTI]

We study the cosmology of K-mouflage theories at the background level. We show that the effects of the scalar field are suppressed at high matter density in the early Universe and only play a role in the late time Universe where the deviations of the Hubble rate from its $\\Lambda$-CDM counterpart can be of the order five percent for redshifts $1 \\lesssim z \\lesssim 5$. Similarly, we find that the equation of state can cross the phantom divide in the recent past and even diverge when the effective scalar energy density goes negative and subdominant compared to matter, preserving the positivity of the squared Hubble rate. These features are present in models for which Big Bang Nucleosynthesis is not affected. We analyze the fate of K-mouflage when the nonlinear kinetic terms give rise to ghosts, particle excitations with negative energy. In this case, we find that the K-mouflage theories can only be considered as an effective description of the Universe at low energy below $1$ keV. In the safe ghost-free models, we find that the equation of state always diverges in the past and changes significantly by a few percent since $z\\lesssim 1$.

Philippe Brax; Patrick Valageas

2014-11-30T23:59:59.000Z

135

Cosmic Microwave Background Anisotropy Window Functions Revisited  

E-Print Network [OSTI]

The primary results of most observations of cosmic microwave background (CMB) anisotropy are estimates of the angular power spectrum averaged through some broad band, called band-powers. These estimates are in turn what are used to produce constraints on cosmological parameters due to all CMB observations. Essential to this estimation of cosmological parameters is the calculation of the expected band-power for a given experiment, given a theoretical power spectrum. Here we derive the "band power" window function which should be used for this calculation, and point out that it is not equivalent to the window function used to calculate the variance. This important distinction has been absent from much of the literature: the variance window function is often used as the band-power window function. We discuss the validity of this assumed equivalence, the role of window functions for experiments that constrain the power in {\\it multiple} bands, and summarize a prescription for reporting experimental results. The analysis methods detailed here are applied in a companion paper to three years of data from the Medium Scale Anisotropy Measurement.

Lloyd Knox

1999-09-28T23:59:59.000Z

136

Multiple concentric annuli for characterizing spatially nonuniform backgrounds  

E-Print Network [OSTI]

A method is presented for estimating the background at a given location on a sky map by interpolating the estimated background from a set of concentric annuli which surround this location. If the background is nonuniform but smoothly varying, this method provides a more accurate (though less precise) estimate than can be obtained with a single annulus. Several applications of multi-annulus background estimation are discussed, including direct testing for point sources in the presence of a nonuniform background, the generation of "surrogate maps" for characterizing false alarm rates, and precise testing of the null hypothesis that the background is uniform.

James Theiler; Jeff Bloch

1999-01-26T23:59:59.000Z

137

Loops and spurs: the angular power spectrum of the Galactic synchrotron background  

SciTech Connect (OSTI)

We present a new model of the diffuse Galactic synchrotron radiation, concentrating on its angular anisotropies. While previous studies have focussed on either the variation of the emissivity on large ( ? kpc) scales, or on fluctuations due to MHD turbulence in the interstellar medium, we unify these approaches to match the angular power spectrum. We note that the usual turbulence cascade calculation ignores spatial correlations at the injection scale ( ? 100 pc) due to compression of the interstellar medium by of O(1000) old supernova remnants the 'radio loops' only four of which are visible in radio maps. This new component naturally provides the otherwise missing power on intermediate and small scales in the all-sky map at 408 MHz. Our model can enable more reliable subtraction of the synchrotron foreground for studies of CMB anisotropies or searches for dark matter annihilation. We conclude with some remarks on the relevance to modelling of the polarised foreground.

Mertsch, Philipp [Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, M/S 29, Menlo Park, CA 94025 (United States); Sarkar, Subir, E-mail: pmertsch@stanford.edu, E-mail: sarkar@nbi.dk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

2013-06-01T23:59:59.000Z

138

Passive background correction method for spatially resolved detection  

DOE Patents [OSTI]

A method for passive background correction during spatially or angularly resolved detection of emission that is based on the simultaneous acquisition of both the passive background spectrum and the spectrum of the target of interest.

Schmitt, Randal L. (Tijeras, NM); Hargis, Jr., Philip J. (Albuquerque, NM)

2011-05-10T23:59:59.000Z

139

Uniform Gauge for D1-brane in General Background  

E-Print Network [OSTI]

We construct uniform gauge D1-brane action in general background. We also discuss how this action transforms under double Wick rotation and determine transformation properties of background fields.

Kluson, J

2015-01-01T23:59:59.000Z

140

MARSAME Appendix B B. SOURCES OF BACKGROUND RADIOACTIVITY  

E-Print Network [OSTI]

: · The Nuclear Regulatory Commission (NRC) provides information concerning background radioactivity in Background as a Residual Radioactivity Criterion for Decommissioning NUREG-1501 (NRC 1994). · The United Nations Scientific

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Muon-induced backgrounds in the CUORICINO experiment  

E-Print Network [OSTI]

background in the neutrinoless double beta decay region ofis searching for neutrinoless double beta decay (0???), a

Andreotti, E.

2010-01-01T23:59:59.000Z

142

Evidence-Based Background Material Underlying Guidance for Federal...  

Broader source: Energy.gov (indexed) [DOE]

Material Underlying Guidance for Federal Agencies in Implementing Strategic Sustainability Performance Plans Evidence-Based Background Material Underlying Guidance for...

143

Surface-wave-enabled darkfield aperture for background suppression during  

E-Print Network [OSTI]

can be directly incorporated onto optical sensors to accom- plish predetection background suppression if the sensor is fully capable of measuring the same weak signal in the absence of background (1, 2- trivial to employ. A sensor that can intrinsically cancel a strong background prior to signal detection

Yang, Changhuei

144

Overcoming High Energy Backgrounds at Pulsed Spallation Sources  

E-Print Network [OSTI]

Instrument backgrounds at neutron scattering facilities directly affect the quality and the efficiency of the scientific measurements that users perform. Part of the background at pulsed spallation neutron sources is caused by, and time-correlated with, the emission of high energy particles when the proton beam strikes the spallation target. This prompt pulse ultimately produces a signal, which can be highly problematic for a subset of instruments and measurements due to the time-correlated properties, and different to that from reactor sources. Measurements of this background have been made at both SNS (ORNL, Oak Ridge, TN, USA) and SINQ (PSI, Villigen, Switzerland). The background levels were generally found to be low compared to natural background. However, very low intensities of high-energy particles have been found to be detrimental to instrument performance in some conditions. Given that instrument performance is typically characterised by S/N, improvements in backgrounds can both improve instrument pe...

Cherkashyna, Nataliia; DiJulio, Douglas D; Khaplanov, Anton; Pfeiffer, Dorothea; Scherzinger, Julius; Cooper-Jensen, Carsten P; Fissum, Kevin G; Ansell, Stuart; Iverson, Erik B; Ehlers, Georg; Gallmeier, Franz X; Panzner, Tobias; Rantsiou, Emmanouela; Kanaki, Kalliopi; Filges, Uwe; Kittelmann, Thomas; Extegarai, Maddi; Santoro, Valentina; Kirstein, Oliver; Bentley, Phillip M

2015-01-01T23:59:59.000Z

145

ESnet supports Sandia and APNIC IPv6 Background Radiation research  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

supports Sandia and APNIC IPv6 Background Radiation research Engineering Services The Network OSCARS Fasterdata IPv6 Network IPv6 Implementation Checklist ESnet IPv6 Mirror Servers...

146

Backgrounds and Projected Limits from Dark Matter Direct Detection Experiments  

E-Print Network [OSTI]

A simple formula is introduced which indicates the amount by which projections of dark matter direct detection experiments are expected to be degraded due to backgrounds.

Scott Dodelson

2008-12-08T23:59:59.000Z

147

accelerator related backgrounds: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the first years... Drozhdin, A I; Mokhov, N V 1996-01-01 2 Cosmic acceleration without dark energy: Background tests and thermodynamic analysis General Relativity & Quantum...

148

A COSMIC MICROWAVE BACKGROUND LENSING MASS MAP AND ITS CORRELATION WITH THE COSMIC INFRARED BACKGROUND  

SciTech Connect (OSTI)

We use a temperature map of the cosmic microwave background (CMB) obtained using the South Pole Telescope at 150 GHz to construct a map of the gravitational convergence to z {approx} 1100, revealing the fluctuations in the projected mass density. This map shows individual features that are significant at the {approx}4{sigma} level, providing the first image of CMB lensing convergence. We cross-correlate this map with Herschel/SPIRE maps covering 90 deg{sup 2} at wavelengths of 500, 350, and 250 {mu}m. We show that these submillimeter (submm) wavelength maps are strongly correlated with the lensing convergence map, with detection significances in each of the three submm bands ranging from 6.7{sigma} to 8.8{sigma}. We fit the measurement of the cross power spectrum assuming a simple constant bias model and infer bias factors of b = 1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed model for the redshift distribution of the dusty galaxies that are contributing to the Herschel/SPIRE maps.

Holder, G. P.; De Haan, T.; Dobbs, M. A.; Dudley, J. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Viero, M. P.; Bock, J. [California Institute of Technology, Pasadena, CA 91125 (United States); Zahn, O. [Berkeley Center for Cosmological Physics, Department of Physics, University of California, and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Aird, K. A. [University of Chicago, Chicago, IL 60637 (United States); Benson, B. A.; Bhattacharya, S.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, Kansas City, MO 64110 (United States); Cho, H-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); Conley, A. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); George, E. M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Halverson, N. W. [Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States); and others

2013-07-01T23:59:59.000Z

149

Non Thermal Features in the Cosmic Neutrino Background  

E-Print Network [OSTI]

I review some of the basic information on the Cosmic Neutrino Background momentum distribution. In particular, I discuss how present data from several cosmological observables such as Big Bang Nucleosynthesis, Cosmic Microwave Background and Large Scale Structure power spectrum constrain possible deviations from a standard Fermi-Dirac thermal distribution.

G. Mangano

2006-03-22T23:59:59.000Z

150

Background Long history of research and education in "nuclear  

E-Print Network [OSTI]

· Degradation Nuclear Materials · Multi physics modelling · Severe nuclear accidents · Non destructive testing#12;Background · Long history of research and education in "nuclear engineering" at Chalmers. · "Nuclear engineering" = multi-disciplinary research area. #12;Background Establishment of the Sustainable

Lemurell, Stefan

151

Revised January 2013 Peabody CollegeBackgroundClearance Office  

E-Print Network [OSTI]

personnel will receive a photo ID badge certifying that they have passed a TBI/FBI background check by the BCO office when your file contains the completed/signed consent AND the cleared TBI/FBI report. Non There are no exemptions. Process Once an individual has been granted clearance based off their TBI/FBI background check

Palmeri, Thomas

152

An electronic radiation of blackbody: Cosmic electron background  

E-Print Network [OSTI]

The Universe owns the electronic radiation of blackbody at temperature 2.725 K, which we call the cosmic electron background. We calculate its radiation spectrum. The energy distribution of number density of electrons in the cosmic electron background becomes zero as energy goes to both zero and infinity. It has one maximum peak near the energy level of 10**(-23) J.

Jian-Miin Liu

2008-02-23T23:59:59.000Z

153

cognitive backgroundCIS4140-2 1 administrivia  

E-Print Network [OSTI]

Cognitive background human-computer interaction understand computer workings (reasonably well) how about humans? once part of psychology now considered cognitive science may also need some sociology later #12;cognitive backgroundCIS4140-2 4 perceptual 2 perceptions considered for UI auditory visual new interfaces

Damon, Craig A.

154

Spinning Test Particle in Kalb-Ramond background  

E-Print Network [OSTI]

In this work we explore the geodesic deviations of spinning test particles in a string inspired Einstein-Kalb Ramond background. Such a background is known to be equivalent to a spacetime geometry with torsion. We have shown here that the antisymmetric Kalb-Ramond field has significant effect on the geodesic deviation of a spinning test particle. A search for an observational evidence of such an effect in astrophysical experiments may lead to a better undestanding of the geometry of the background spacetime.

Debaprasad Maity; Soumitra SenGupta; Sourav Sur

2005-05-19T23:59:59.000Z

155

Muon-induced backgrounds in the CUORICINO experiment  

SciTech Connect (OSTI)

To better understand the contribution of cosmic ray muons to the CUORICINO background, ten plastic scintillator detectors were installed at the CUORICINO site and operated during 3 months of the CUORICINO experiment. From these measurements, an upper limit of 0.0021 counts/keV {center_dot} kg {center_dot} yr (95% C.L.) was obtained on the cosmic ray induced background in the neutrinoless double beta decay region of interest. The measurements were compared to Geant4 simulations, which are similar to those that will be used to estimate the backgrounds in CUORE.

Andreotti, E; Arnaboldi, C; Avignone, F T; Balata, M; Bandac, I; Barucci, M; Beeman, J W; Bellini, F; Bloxham, T; Brofferio, C; Bryant, A; Bucci, C; Canonica, L; Capelli, S; Carbone, L; Carrettoni, M; Clemenza, M; Cremonesi, O; Creswick, R J; Domizio, S D; Dolinski, M J; Ejzak, L; Faccini, R; Farach, H A; Ferri, E; Ferroni, F; Firoini, E; Foggetta, L; Giachero, A; Gironi, L; Giuliani, A; Gorla, P; Guardincerri, E; Gutierrez, T D; Haller, E E; Kadel, R; Kazkaz, K; Kraft, S; Kogler, L; Kolomensky, Y G; Maiano, C; Maruyama, R H; Martinez, C; Martinez, M; Mizouni, L; Morganti, S; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; Orio, F; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pirro, S; Previtali, E; Risegari, L; Rosenfeld, C; Rusconi, C; Salvioni, C; Sangiorgio, S; Schaeffer, D; Scielzo, N D; Sisti, M; Smith, A R; Tomei, C; Ventura, G; Vignati, M

2009-11-16T23:59:59.000Z

156

Flavor singlet physics in lattice QCD with background fields  

SciTech Connect (OSTI)

We show that hadronic matrix elements can be extracted from lattice simulations with background fields that arise from operator exponentiation. Importantly, flavor-singlet matrix elements can be evaluated without requiring the computation of disconnected diagrams, thus facilitating a calculation of the quark contribution to the spin of the proton and the singlet axial coupling, g{sub A}{sup 0}. In the two-nucleon sector, a background field approach will allow calculation of the magnetic and quadrupole moments of the deuteron and an investigation of the EMC effect directly from lattice QCD. Matrix elements between states of differing momenta are also analyzed in the presence of background fields.

Detmold, W. [Department of Physics, University of Washington, Box 351560, Seattle, Washington 98195 (United States)

2005-03-01T23:59:59.000Z

157

Reduction of background clutter in structured lighting systems  

DOE Patents [OSTI]

Methods for segmenting the reflected light of an illumination source having a characteristic wavelength from background illumination (i.e. clutter) in structured lighting systems can comprise pulsing the light source used to illuminate a scene, pulsing the light source synchronously with the opening of a shutter in an imaging device, estimating the contribution of background clutter by interpolation of images of the scene collected at multiple spectral bands not including the characteristic wavelength and subtracting the estimated background contribution from an image of the scene comprising the wavelength of the light source and, placing a polarizing filter between the imaging device and the scene, where the illumination source can be polarized in the same orientation as the polarizing filter. Apparatus for segmenting the light of an illumination source from background illumination can comprise an illuminator, an image receiver for receiving images of multiple spectral bands, a processor for calculations and interpolations, and a polarizing filter.

Carlson, Jeffrey J.; Giles, Michael K.; Padilla, Denise D.; Davidson Jr., Patrick A.; Novick, David K.; Wilson, Christopher W.

2010-06-22T23:59:59.000Z

158

Inductive Rules, Background Knowledge, and Skepticism Daniel Steel  

E-Print Network [OSTI]

Inductive Rules, Background Knowledge, and Skepticism Daniel Steel Department of Philosophy 503 S. Kedzie Hall Michigan State University East Lansing, MI 48823-1032 Email: steel@msu.edu #12;Abstract

Steel, Daniel

159

1 Mathematical Background 1 1.1 Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . 1  

E-Print Network [OSTI]

Contents 1 Mathematical Background 1 1.1 Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Computability Theory . . . . . . . . . . . . . . . . . . . . 4 1.3 Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Probability Theory . . . . . . . . . . . . . . . . . . . . . . 8 1.5 Exercises and Problems

Goodman, James R.

160

1 Introduction 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  

E-Print Network [OSTI]

Contents 1 Introduction 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Our Goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.3 ICSI's HMM/ANN Hybrid Speech Recognition System . . . . . . . . 2 1.4 What is Multi­band Processing

Mirghafori, N. Nikki

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Higgs boson production at hadron colliders: Signal and background processes  

SciTech Connect (OSTI)

We review the theoretical status of signal and background calculations for Higgs boson production at hadron colliders. Particular emphasis is given to missing NLO results, which will play a crucial role for the Tevatron and the LHC.

David Rainwater; Michael Spira; Dieter Zeppenfeld

2004-01-12T23:59:59.000Z

162

Lovelock black holes in a string cloud background  

E-Print Network [OSTI]

We present an exact static, spherically symmetric black hole solution to the third order Lovelock gravity with a string cloud background in seven dimensions for the special case when the second and third order Lovelock coefficients are related via $\\tilde{\\alpha}^2_2=3\\tilde{\\alpha}_3\\;(\\equiv\\alpha^2)$. Further, we examine thermodynamic properties of this black hole to obtain exact expressions for mass, temperature, entropy and also perform the thermodynamic stability analysis. We see that a string cloud background makes a profound influence on horizon structure, thermodynamic properties and the stability of black holes. Interestingly, the entropy of the black hole is unaffected due to a string cloud background. However, the critical solution for thermodynamic stability is being affected by a string cloud background.

Tae-Hun Lee; Dharmanand Baboolal; Sushant G. Ghosh

2014-09-12T23:59:59.000Z

163

Superluminal Velocity of Photons in a Gravitational Background  

E-Print Network [OSTI]

The influence of radiative corrections on the photon propagation in a gravitational background is investigated without the low-frequency approximation $\\omega \\ll m$. The conclusion is made in this way that the velocity of light can exceed unity.

I. B. Khriplovich

1994-11-20T23:59:59.000Z

164

Modeling surface backgrounds from radon progeny plate-out  

SciTech Connect (OSTI)

The next generation low-background detectors operating deep underground aim for unprecedented low levels of radioactive backgrounds. The surface deposition and subsequent implantation of radon progeny in detector materials will be a source of energetic background events. We investigate Monte Carlo and model-based simulations to understand the surface implantation profile of radon progeny. Depending on the material and region of interest of a rare event search, these partial energy depositions can be problematic. Motivated by the use of Ge crystals for the detection of neutrinoless double-beta decay, we wish to understand the detector response of surface backgrounds from radon progeny. We look at the simulation of surface decays using a validated implantation distribution based on nuclear recoils and a realistic surface texture. Results of the simulations and measured ? spectra are presented.

Perumpilly, G.; Guiseppe, V. E.; Snyder, N. [University of South Dakota, Vermillion, South Dakota 57069 (United States)] [University of South Dakota, Vermillion, South Dakota 57069 (United States)

2013-08-08T23:59:59.000Z

165

The Cosmic Near Infrared Background: Remnant Light from Early Stars  

E-Print Network [OSTI]

The redshifted ultraviolet light from early stars at z ~ 10 contributes to the cosmic near infrared background. We present detailed calculations of its spectrum with various assumptions about metallicity and mass spectrum of early stars. We show that if the near infrared background has a stellar origin, metal-free stars are not the only explanation of the excess near infrared background; stars with metals (e.g. Z=1/50 Z_sun) can produce the same amount of background intensity as the metal-free stars. We quantitatively show that the predicted average intensity at 1-2 microns is essentially determined by the efficiency of nuclear burning in stars, which is not very sensitive to metallicity. We predict \

Elizabeth Fernandez; Eiichiro Komatsu

2005-08-08T23:59:59.000Z

166

EXTRAGALACTIC VERY HIGH ENERGY GAMMA-RAY BACKGROUND  

SciTech Connect (OSTI)

We study the origin of the extragalactic diffuse gamma-ray background using the data from the Fermi telescope. To estimate the background level, we count photons at high Galactic latitudes |b| > 60 Degree-Sign . Subtracting photons associated with known sources and the residual cosmic-ray and Galactic diffuse backgrounds, we estimate the extragalactic gamma-ray background (EGB) flux. We find that the spectrum of EGB in the very high energy band above 30 GeV follows the stacked spectrum of BL Lac objects. Large Area Telescope data reveal the positive (1 + z) {sup k}, 1 < k < 4 cosmological evolution of the BL Lac source population consistent with that of their parent population, Fanaroff-Riley type I radio galaxies. We show that EGB at E > 30 GeV could be completely explained by emission from unresolved BL Lac objects if k {approx_equal} 3.

Neronov, A. [ISDC Data Center for Astrophysics, Chemin d'Ecogia 16, CH-1290 Versoix (Switzerland); Semikoz, D. V. [APC, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France)

2012-09-20T23:59:59.000Z

167

Holographic superconductor developed in BTZ black hole background with backreactions  

E-Print Network [OSTI]

We develop a holographic superconductor in BTZ black hole background with backreactions. We investigate the influence of the backreaction on the condensation of the scalar hair and the dynamics of perturbation in the background spacetime. When the Breitenlohner-Freedman bound is approached, we argue that only one of two possible operators can reflect the real property of the condensation in the holographic superconductor. This argument is supported by the investigation in dynamics.

Yunqi Liu; Qiyuan Pan; Bin Wang

2011-06-22T23:59:59.000Z

168

The X-ray background and the evolution of AGN  

E-Print Network [OSTI]

We discuss the constraints on the AGN evolution from the cosmic X-ray background and source counts. A synthesis model to fit the X-ray background is presented. In the model, the spectrum of type 2 AGN has been modeled including Compton down--scattering within the absorbing material. Besides, we introduced a dependence on redshift of the relative number of obscured sources and found a decrease of the fraction of type 2 AGN at redshifts larger than 2.

Fulvio Pompilio; Fabio La Franca; Giorgio Matt

1999-09-23T23:59:59.000Z

169

Analysis of alpha backgrounds in the DEAP-1 detector  

E-Print Network [OSTI]

DEAP-1 is a 7 kg liquid argon dark matter detector used to prototype the tonne scale DEAP-3600 detector at SNOLAB.We present an analysis of the alpha particle backgrounds in DEAP-1 and isolate the radiations from various 222Rn daughters at various locations within the detector. The backgrounds will be removed by event position reconstruction and strict controls of material purity.

Kevin S. Olsen

2009-06-01T23:59:59.000Z

170

Muon-induced backgrounds in the CUORICINO experiment  

SciTech Connect (OSTI)

To better understand the contribution of cosmic ray muons to the CUORICINO background, ten plastic scintillator detectors were installed at the CUORICINO siteand operated during the final 3 months of the experiment. From these measurements, an upper limit of 0.0021 counts/(keV.kg.yr) (95percent c.l.) was obtained on the cosmicray induced background in the neutrinoless double beta decay region of interest. The measurements were also compared to Geant4 simulations.

Andreotti, E.; Arnaboldi, C.; Avignone III, F. T.; Balata, M.; Bandac, I.; Barucci, M.; Beeman, J. W.; Bellini, F.; Bloxham, T.; Brofferio, C.; Bryant, A.; Bucci, C.; Canonica, L.; Capelli, S.; Carbone, L.; Carrettoni, M.; Clemenza, M.; Cremonesi, O.; Creswick, R. J.; Domizio, S. Di; Dolinski, M. J.; Ejzak, L.; Faccini, R.; Farach, H. A.; Ferri, E.; Ferroni, F.; Fiorini, E.; Foggetta, L.; Giachero, A.; Gironi, L.; Giuliani, A.; Gorla, P.; Guardincerri, E.; Gutierrez, T. D.; Haller, E. E.; Kadel, R.; Kazkaz, K.; Kraft, S.; Kogler, L.; Kolomensky, Yu. G.; Maiano, C.; Maruyama, R. H.; Martinez, C.; Martinez, M.; Mizouni, L.; Morganti, S.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; Orio, F.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pirro, S.; Previtali, E.; Risegari, L.; Rosenfeld, C.; Rusconi, C.; Salvioni, C.; Sangiorgio, S.; Schaeffer, D.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Tomei, C.; Ventura, G.; Vignati, M.

2010-04-15T23:59:59.000Z

171

Air fluidized balls in a background of smaller beads  

E-Print Network [OSTI]

We report on quasi-two-dimensional granular systems in which either one or two large balls is fluidized by an upflow of air in the presence of a background of several hundred smaller beads. A single large ball is observed to propel ballistically in nearly circular orbits, in direct contrast to the Brownian behavior of a large ball fluidized in the absence of this background. Further, the large ball motion satisfies a Langevin equation with an additional speed-dependent force acting in the direction of motion. This results in a non-zero average speed of the large ball that is an order of magnitude faster than the root mean square speed of the background balls. Two large balls fluidized in the absence of the small-bead background experience a repulsive force depending only on the separation of the two balls. With the background beads present, by contrast, the ball-ball interaction becomes velocity-dependent and attractive. The attraction is long-ranged and inconsistent with a depletion model; instead, it is mediated by local fluctuations in the density of the background beads which depends on the large balls' motion.

M. E. Beverland; L. J. Daniels; D. J. Durian

2010-12-02T23:59:59.000Z

172

Background reduction and sensitivity for germanium double beta decay experiments  

E-Print Network [OSTI]

Germanium detectors have very good capabilities for the investigation of rare phenomena like the neutrinoless double beta decay. Rejection of the background entangling the expected signal is one primary goal in this kind of experiments. Here, the attainable background reduction in the energy region where the neutrinoless double beta decay signal of 76Ge is expected to appear has been evaluated for experiments using germanium detectors, taking into consideration different strategies like the granularity of the detector system, the segmentation of each individual germanium detector and the application of Pulse Shape Analysis techniques to discriminate signal from background events. Detection efficiency to the signal is affected by background rejection techniques, and therefore it has been estimated for each of the background rejection scenarios considered. Finally, conditions regarding crystal mass, radiopurity, exposure to cosmic rays, shielding and rejection capabilities are discussed with the aim to achieve a background level of 10-3 c keV-1 kg-1 y-1 in the region of interest, which would allow to explore neutrino effective masses around 40 meV.

H. Gmez; S. Cebrin; J. Morales; J. A. Villar

2007-08-29T23:59:59.000Z

173

Background-independent measurement of $?_{13}$ in Double Chooz  

E-Print Network [OSTI]

The oscillation results published by the Double Chooz collaboration in 2011 and 2012 rely on background models substantiated by reactor-on data. In this analysis, we present a background-model-independent measurement of the mixing angle $\\theta_{13}$ by including 7.53 days of reactor-off data. A global fit of the observed neutrino rates for different reactor power conditions is performed, yielding a measurement of both $\\theta_{13}$ and the total background rate. The results on the mixing angle are improved significantly by including the reactor-off data in the fit, as it provides a direct measurement of the total background rate. This reactor rate modulation analysis considers antineutrino candidates with neutron captures on both Gd and H, whose combination yields $\\sin^2(2\\theta_{13})=$ 0.102 $\\pm$ 0.028(stat.) $\\pm$ 0.033(syst.). The results presented in this study are fully consistent with the ones already published by Double Chooz, achieving a competitive precision. They provide, for the first time, a determination of $\\theta_{13}$ that does not depend on a background model.

Y. Abe; J. C. dos Anjos; J. C. Barriere; E. Baussan; I. Bekman; M. Bergevin; T. J. C. Bezerra; L. Bezrukov; E. Blucher; C. Buck; J. Busenitz; A. Cabrera; E. Caden; L. Camilleri; R. Carr; M. Cerrada; P. -J. Chang; E. Chauveau; P. Chimenti; A. P. Collin; E. Conover; J. M. Conrad; J. I. Crespo-Anadn; K. Crum; A. Cucoanes; E. Damon; J. V. Dawson; D. Dietrich; Z. Djurcic; M. Dracos; M. Elnimr; A. Etenko; M. Fallot; F. von Feilitzsch; J. Felde; S. M. Fernandes; V. Fischer; D. Franco; M. Franke; H. Furuta; I. Gil-Botella; L. Giot; M. Gger-Neff; L. F. G. Gonzalez; L. Goodenough; M. C. Goodman; C. Grant; N. Haag; T. Hara; J. Haser; M. Hofmann; G. A. Horton-Smith; A. Hourlier; M. Ishitsuka; J. Jochum; C. Jollet; F. Kaether; L. N. Kalousis; Y. Kamyshkov; D. M. Kaplan; T. Kawasaki; E. Kemp; H. de Kerret; T. Konno; D. Kryn; M. Kuze; T. Lachenmaier; C. E. Lane; T. Lasserre; A. Letourneau; D. Lhuillier; H. P. Lima Jr; M. Lindner; J. M. Lpez-Castao; J. M. LoSecco; B. K. Lubsandorzhiev; S. Lucht; J. Maeda; C. Mariani; J. Maricic; J. Martino; T. Matsubara; G. Mention; A. Meregaglia; T. Miletic; R. Milincic; A. Minotti; Y. Nagasaka; K. Nakajima; Y. Nikitenko; P. Novella; M. Obolensky; L. Oberauer; A. Onillon; A. Osborn; C. Palomares; I. M. Pepe; S. Perasso; P. Pfahler; A. Porta; G. Pronost; J. Reichenbacher; B. Reinhold; M. Rhling; R. Roncin; S. Roth; B. Rybolt; Y. Sakamoto; R. Santorelli; F. Sato; A. C. Schilithz; S. Schnert; S. Schoppmann; M. H. Shaevitz; R. Sharankova; S. Shimojima; V. Sibille; V. Sinev; M. Skorokhvatov; E. Smith; J. Spitz; A. Stahl; I. Stancu; L. F. F. Stokes; M. Strait; A. Stken; F. Suekane; S. Sukhotin; T. Sumiyoshi; Y. Sun; R. Svoboda; K. Terao; A. Tonazzo; H. H. Trinh Thi; G. Valdiviesso; N. Vassilopoulos; C. Veyssiere; M. Vivier; S. Wagner; H. Watanabe; C. Wiebusch; L. Winslow; M. Wurm; G. Yang; F. Yermia; V. Zimmer

2014-04-25T23:59:59.000Z

174

Cavern background measurement with the ATLAS RPC system  

E-Print Network [OSTI]

The measurement of cavern background has been carried out systematically since the beginning of LHC, as soon as the luminosity produced a detectable signal, from L = 10^28 cm^2s^1 of the early 2010 operation up to L=10^28 cm^2s^1 at the end of 2011 proton-proton run, which is just 1/3 of the nominal LHC luminosity. The reason for this is to early foresee the running condition for the detector for the nominal LHC luminosity and beyond, in view of the super-LHC upgrade. Background Montecarlo calculations have been validated against data and the background map analysis pointed out hotspots due to localized cracks in the radiation shielding. The RPCs participated to this effort since the earliest stages providing an accurate correlation between luminosity and background, a 3D background map in the barrel region and a direct measurement of the cavern activation. Moreover due to the high sensitivity and very good signal to noise ratio of the proposed method, based on the gap current, the measurement was provided in...

Aielli, G; The ATLAS collaboration

2012-01-01T23:59:59.000Z

175

The local potential approximation in the background field formalism  

E-Print Network [OSTI]

Working within the familiar local potential approximation, and concentrating on the example of a single scalar field in three dimensions, we show that the commonly used approximation method of identifying the total and background fields, leads to pathologies in the resulting fixed point structure and the associated spaces of eigenoperators. We then show how a consistent treatment of the background field through the corresponding modified shift Ward identity, can cure these pathologies, restoring universality of physical quantities with respect to the choice of dependence on the background field, even within the local potential approximation. Along the way we point out similarities to what has been previously found in the f(R) approximation in asymptotic safety for gravity.

I. Hamzaan Bridle; Juergen A. Dietz; Tim R. Morris

2014-03-20T23:59:59.000Z

176

Position sensitive detection of neutrons in high radiation background field  

SciTech Connect (OSTI)

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high ? and e{sup ?} radiation background. We make use of a planar silicon pixelated (pixel size: 55 55 ?m{sup 2}) spectroscopic Timepix detector adapted for neutron detection utilizing very thin {sup 10}B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10{sup ?4}.

Vavrik, D., E-mail: vavrik@itam.cas.cz [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, Prague (Czech Republic); Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic); Jakubek, J.; Pospisil, S. [Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic)] [Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic); Vacik, J. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez, 250 68 Prague, Czech Republic (Czech Republic)] [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez, 250 68 Prague, Czech Republic (Czech Republic)

2014-01-15T23:59:59.000Z

177

Reducing backgrounds in the higgs factory muon collider detector  

SciTech Connect (OSTI)

A preliminary design of the 125-GeV Higgs Factory (HF) Muon Collider (MC) has identified an enormous background loads on the HF detector. This is related to the twelve times higher muon decay probability at HF compared to that previously studied for the 1.5-TeV MC. As a result of MARS15 optimization studies, it is shown that with a carefully designed protection system in the interaction region, in the machine-detector interface and inside the detector one can reduce the background rates to a manageable level similar to that achieved for the optimized 1.5-TeV case. The main characteristics of the HF detector background are presented for the configuration found.

Mokhov, N. V.; Tropin, I. S.

2014-06-01T23:59:59.000Z

178

Reducing 68Ge Background in Dark Matter Experiments  

SciTech Connect (OSTI)

Experimental searches for dark matter include experiments with sub-0.5 keV-energy threshold high purity germanium detectors. Experimental efforts, in partnership with the CoGeNT Collaboration operating at the Soudan Underground Laboratory, are focusing on energy threshold reduction via noise abatement, reduction of backgrounds from cosmic ray generated isotopes, and ubiquitous environmental radioactive sources. The most significant cosmic ray produced radionuclide is 68Ge. This paper evaluates reducing this background by freshly mining and processing germanium ore. The most probable outcome is a reduction of the background by a factor of two, and at most a factor of four. A very cost effective alternative is to obtain processed Ge as soon as possible and store it underground for 18 months.

Kouzes, Richard T.; Orrell, John L.

2011-03-01T23:59:59.000Z

179

Direct Imaging of Exoplanets Without Background Subtraction: Implications for ELTs  

E-Print Network [OSTI]

The ultra-high contrast capability required to form images of other solar systems is arguably the highest-profile challenge in astronomy today. The current high-contrast imaging efforts all require background subtraction to separate the planetary image from the image of the host star. Background estimation is difficult due to the presence of non-common path aberrations (NCPAs) that change with time. The only major source of information that is not being utilized by current efforts is the random encoding of the planetary image and the NCPAs by the atmosphere on millisecond time-scales. Here, a method that utilizes this information in order to avoid background subtraction altogether is proposed. This new paradigm will allow simultaneous estimation of the time-dependent NCPAs and the planetary image via rigorous statistical inference procedures. These procedures are fully compatible with other information sources, such as diurnal field rotation and spectral diversity. Given the open-ended nature of the backgroun...

Frazin, Richard A

2015-01-01T23:59:59.000Z

180

Radiative emission of neutrino pair free of quantum electrodynamic backgrounds  

E-Print Network [OSTI]

A scheme of quantum electrodynamic (QED) background-free radiative emission of neutrino pair (RENP) is proposed in order to achieve precision determination of neutrino properties so far not accessible. The important point for the background rejection is the fact that the dispersion relation between wave vector along propagating direction in wave guide (and in a photonic-crystal type fiber) and frequency is modified by a discretized non-vanishing effective mass. This effective mass acts as a cutoff of allowed frequencies, and one may select the RENP photon energy region free of all macro-coherently amplified QED processes by choosing the cutoff larger than the mass of neutrinos.

M. Yoshimura; N. Sasao; M. Tanaka

2015-01-23T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

A Stable Magnetic Background in SU(2) QCD  

E-Print Network [OSTI]

Motivated by the instability of the Savvidy-Nielsen-Olesen (SNO) vacuum we make a systematic search for a stable magnetic background in pure SU(2) QCD. It is shown that Wu-Yang monopole-antimonopole pair is unstable under vacuum fluctuations. However, it is shown that a pair of axially symmetric monopole-antimonopole string configuration is stable, provided the distance between the two strings is small enough (less than a critical value). The existence of a stable monopole-antimonopole string background strongly supports that a magnetic condensation of monopole-antimonopole pairs can indeed generate a dynamical symmetry breaking, and thus a desired magnetic confinement of color, in QCD.

Y. M. Cho; D. G. Pak

2005-10-24T23:59:59.000Z

182

Technical background document for soil screening guidance. Review draft  

SciTech Connect (OSTI)

The document provides the technical background behind the development of the November 1994 Soil Screening Guidance for Superfund. These documents define the Soil Screening framework, a suite of methodologies for developing Soil Screening Levels (SSLs) for 107 chemicals commonly found at Superfund sites. The document is an updated version of the background document developed in support of the September 30, 1993, draft SSL guidance (PB93-963508). The document and the Guidance is available for public comment and is currently undergoing extensive peer review. Because the guidance is still under review, it and this document should not be used until they are finalized following this rigorous technical review and public comment.

Not Available

1994-12-01T23:59:59.000Z

183

Beam-Induced Backgrounds in the CLIC Detectors  

E-Print Network [OSTI]

The beam parameters of the proposed CLIC linear electron-positron collider with a centre-of-mass energy of up to 3 TeV will lead to high rates of beam-induced background events. In this note simulation studies of ?? ? hadron interactions and of incoherent electron-positron pair production are presented. The CLIC detector concepts and their optimisation to reduce background occupancies are described. The characteristics of the events are discussed and resulting occupancies and energy deposits, as well as expected levels of both total ionising dose and displacement damage in the detectors are discussed.

Dannheim, D

2012-01-01T23:59:59.000Z

184

The Cosmic Microwave Background: Beyond the Power Spectrum  

E-Print Network [OSTI]

Much recent work on the cosmic microwave background (CMB) has focussed on the angular power spectrum of temperature anisotropies and particularly on the recovery of cosmological parameters from acoustic peaks in the power spectrum. However, there is more that can conceivably be done with CMB measurements. Here I briefly survey a few such ideas: cross-correlation with other cosmic backgrounds as a probe of the density of the Universe; CMB polarization as a gravitational-wave detector; secondary anisotropies and the ionization history of the Universe; tests of alternative-gravity theories; polarization, the Sunyaev-Zeldovich effect, and cosmic variance; and tests for a neutrino mass.

Marc Kamionkowski

1998-09-24T23:59:59.000Z

185

Stochastic Background Search Correlating ALLEGRO with LIGO Engineering Data  

E-Print Network [OSTI]

We describe the role of correlation measurements between the LIGO interferometer in Livingston, LA, and the ALLEGRO resonant bar detector in Baton Rouge, LA, in searches for a stochastic background of gravitational waves. Such measurements provide a valuable complement to correlations between interferometers at the two LIGO sites, since they are sensitive in a different, higher, frequency band. Additionally, the variable orientation of the ALLEGRO detector provides a means to distinguish gravitational wave correlations from correlated environmental noise. We describe the analysis underway to set a limit on the strength of a stochastic background at frequencies near 900 Hz using ALLEGRO data and data from LIGO's E7 Engineering Run.

John T Whelan; Edward Daw; Ik Siong Heng; Martin P McHugh; Albert Lazzarini

2003-08-14T23:59:59.000Z

186

Stochastic Background Search Correlating ALLEGRO with LIGO Engineering Data  

E-Print Network [OSTI]

We describe the role of correlation measurements between the LIGO interferometer in Livingston, LA, and the ALLEGRO resonant bar detector in Baton Rouge, LA, in searches for a stochastic background of gravitational waves. Such measurements provide a valuable complement to correlations between interferometers at the two LIGO sites, since they are sensitive in a different, higher, frequency band. Additionally, the variable orientation of the ALLEGRO detector provides a means to distinguish gravitational wave correlations from correlated environmental noise. We describe the analysis underway to set a limit on the strength of a stochastic background at frequencies near 900 Hz using ALLEGRO data and data from LIGO's E7 Engineering Run.

Whelan, J T; Heng, I S; McHugh, M P; Lazzarini, A; Whelan, John T; Daw, Edward; Heng, Ik Siong; Hugh, Martin P Mc; Lazzarini, Albert

2003-01-01T23:59:59.000Z

187

Radiative emission of neutrino pair free of quantum electrodynamic backgrounds  

E-Print Network [OSTI]

A scheme of quantum electrodynamic (QED) background-free radiative emission of neutrino pair (RENP) is proposed in order to achieve precision determination of neutrino properties so far not accessible. The important point for the background rejection is the fact that the dispersion relation between wave vector along propagating direction in wave guide (and in a photonic-crystal type fiber) and frequency is modified by a discretized non-vanishing effective mass. This effective mass acts as a cutoff of allowed frequencies, and one may select the RENP photon energy region free of all macro-coherently amplified QED processes by choosing the cutoff larger than the mass of neutrinos.

Yoshimura, M; Tanaka, M

2015-01-01T23:59:59.000Z

188

Project Background Transportation projects can stall for a number of  

E-Print Network [OSTI]

Project Background Transportation projects can stall for a number of reasons. One reason is that those responsible for the project lack the skills to move beyond conflicts with resource agency staff work on a pilot program aimed at confronting these two causes. The project had these objectives

Minnesota, University of

189

II. HISTORICAL BACKGROUND Since 1977 the University of Oregon Solar  

E-Print Network [OSTI]

2 II. HISTORICAL BACKGROUND Since 1977 the University of Oregon Solar Monitoring Laboratory has operated a solar radiation monitoring network in the Pacific Northwest. The number of stations participat of utilities headed by the Eugene Water and Electric Board initiated the Re- gional Solar Radiation Monitoring

Oregon, University of

190

Power Systems Engineering Research Center PSERC Background Paper  

E-Print Network [OSTI]

Power Systems Engineering Research Center PSERC Background Paper Monitoring and Control of Power level control centers. However, there is little standardization of the monitoring process and data to the control center operators and security coordinators, or to the computers that can detect anomalous patterns

191

3.5 Nanowire Sensors 3.5.1 Background  

E-Print Network [OSTI]

117 3.5 Nanowire Sensors 3.5.1 Background Nanowires are solid, rod-like materials with diameters that similar commercial products will eventually be available. 3.5.2 Description Nanowire sensors have et al. 2003). A comprehensive review of current research activities on chemical sensors based

192

STRING LOOPS IN BACKGROUND FIELDS Scott Alan Yost  

E-Print Network [OSTI]

excellent collaborators. They have made my stay at Princeton very productive and enjoyable. I thank E. LiebSTRING LOOPS IN BACKGROUND FIELDS Scott Alan Yost A dissertation presented to the faculty formalism. ii #12;Acknowledgements I would like to thank my advisor, Chiara Nappi, for her support, advice

Yost, Scott

193

ECONOMICS OF AGRICULTURE AND WILDLIFE A Background Report on the  

E-Print Network [OSTI]

a system of economic incentives and develop cost effective solutions to agricultural and wildlife issues#12;ECONOMICS OF AGRICULTURE AND WILDLIFE A Background Report on the Potential for Use of Economic and Associated Floodplains prepared by Richard M. Porter for Socio-Economic Section Sustainability Division

194

Amphibian Decline or Extinction? Current Declines Dwarf Background Extinction Rate  

E-Print Network [OSTI]

the background amphibian extinction rate. If current estimates of amphibian species in imminent danger). Although it is thought that 35 species of amphibians have gone extinct since 1500, this number may). Another 1,896 species may be in imminent danger of extinction (IUCN et al., 2006). All of these estimates

McCallum, Malcolm

195

Compressed Gas Cylinder Safety I. Background. Due to the nature  

E-Print Network [OSTI]

Compressed Gas Cylinder Safety I. Background. Due to the nature of gas cylinders hazards of a ruptured cylinder. There are almost 200 different types of materials in gas cylinders, there are several general procedures to follow for safe storage and handling of a compressed gas cylinder: II

Suzuki, Masatsugu

196

1 Background 1.1 Topic of research  

E-Print Network [OSTI]

1 Background 1.1 Topic of research Mathematical quantitative tools (like probabil- ity theory analyses on the basis of these meth- ods. 1.2 Academic and industrial con- text Interference in a security section 1.3). Applications of this work can be found in large scale, mission critical, security related

Hunt, Sebastian

197

Background Suppression in Near-Field Optical Imaging  

E-Print Network [OSTI]

irradiation of the optical antenna (e.g., tip or particle) also directly irradiates the sample and thereforeBackground Suppression in Near-Field Optical Imaging Christiane Ho¨ppener, Ryan Beams, and Lukas Novotny* Institute of Optics, UniVersity of Rochester, Rochester, New York 14627 Received December 25

Novotny, Lukas

198

Statistical Isotropy of the Cosmic Microwave Background Anisotropy  

E-Print Network [OSTI]

Statistical Isotropy of the Cosmic Microwave Background Anisotropy Amir Hajian #3; I.U.C.A.A., Pune to be statistically isotropic, i.e., statistical expectation values of the temperature #29;uctuations are preserved under rotations of the sky. Only under statistical isotropy does the widely used angular power spectrum

Souradeep, Tarun

199

Power Systems Engineering Research Center PSERC Background Paper  

E-Print Network [OSTI]

Power Systems Engineering Research Center PSERC Background Paper Power System Operations of Illinois at Urbana-Champaign September 10, 2003 Before the August 14th 2003 blackout most people gave little thought to the source of the power that comes out of the electric outlet. And why should they

200

Optimal coherent control of CARS: signal enhancement and background elimination  

E-Print Network [OSTI]

The ability to enhance resonant signals and eliminate the non-resonant background is analyzed for Coherent Anti-Stokes Raman Scattering (CARS). The analysis is done at a specific frequency as well as for broadband excitation using femtosecond pulse-shaping techniques. An appropriate objective functional is employed to balance resonant signal enhancement against non-resonant background suppression. Optimal enhancement of the signal and minimization of the background can be achieved by shaping the probe pulse alone while keeping the pump and Stokes pulses in transform-limited-form (TLF). In some cases analytical forms for the probe pulse can be found, and numerical simulations are carried out for other circumstances. It is found that a good approximate solution for the optimal pulse in the two-pulse CARS is a superposition of linear and arctangent type phases for the pump. The well-known probe delay method is shown to be a quasi-optimal scheme for background suppression. The results should provide a basis to improve the performance of CARS spectroscopy and microscopy.

Fang Gao; Feng Shuang; JunHui Shi; Herschel Rabitz; HaiFeng Wang; JiXin Cheng

2012-03-28T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Power Systems Engineering Research Center PSERC Background Paper  

E-Print Network [OSTI]

Power Systems Engineering Research Center PSERC Background Paper What is Reactive Power? Peter W-Champaign September 16, 2003 Engineering talk Reactive power is a quantity that is normally only defined time). In that sense, these are pulsating quantities. Because of this, the power being transmitted down

202

Low Background Radiation Experiment Yields Interesting Preliminary Results  

Broader source: Energy.gov [DOE]

CARLSBAD, N.M., May 18, 2011 New Mexico State University?s Low Background Radiation Experiment (LBRE), which takes place 2,150 feet below the earth?s surface at the Waste Isolation Pilot Plant, recently released some results about the project?s first two years of experimentation.

203

Cosmic and Galactic Neutrino Backgrounds from Thermonuclear Sources  

E-Print Network [OSTI]

We estimate energy spectra and fluxes at the Earth's surface of the cosmic and Galactic neutrino backgrounds produced by thermonuclear reactions in stars. The extra-galactic component is obtained by combining the most recent estimates of the cosmic star formation history and the stellar initial mass function with accurate theoretical predictions of the neutrino yields all over the thermonuclear lifetime of stars of different masses. Models of the structure and evolution of the Milky Way are used to derive maps of the expected flux generated by Galactic sources as a function of sky direction. The predicted neutrino backgrounds depend only slightly on model parameters. In the relevant 50 keV-10 MeV window, the total flux of cosmic neutrinos ranges between 20 and 65 particles per square cm per s. Neutrinos reaching the Earth today have been typically emitted at redshift z~2. Their energy spectrum peaks at E~0.1-0.3 MeV. The energy and entropy densities of the cosmic background are negligible with respect to the thermal contribution of relic neutrinos originated in the early universe. In every sky direction, the cosmic background is outnumbered by the Galactic one, whose integrated flux amounts to 300-1000 particles per square cm per s. The emission from stars in the Galactic disk contributes more than 95 per cent of the signal.

Cristiano Porciani; Silvia Petroni; Giovanni Fiorentini

2003-11-20T23:59:59.000Z

204

The prospects for polarized target materials with pure carbon background  

SciTech Connect (OSTI)

None of the materials presently in common use for polarized proton targets has a pure carbon nuclear background. The alcohols and diols contain some oxygen, and the ammonia and amine-based materials contain nitrogen and/or other noncarbon species. In the latter cases the noncarbon nuclei are measurably polarized as a concomitant of the process used to polarize the hydrogen nuclei. The relative simplicity of a pure carbon background would be advantageous for most types of scattering experiments and perhaps crucial for some. In addition to simplifying the kinematics of background events, pure carbon is relatively easy to prepare as a ``dummy`` target for background subtraction. Also, in such a target material, {sup 13}C-enrichment would yield a clean polarized {sup 13}C material. In this note I explore the possibilities for such materials, touching upon only what I consider to be the ``high`` points. The subject matter is capable of nearly endless ramification and speculation. In fact, owing to a general lack of relevant experimental data, even this relatively brief note contains much that is speculative to some degree.

Hill, D.A.

1992-10-06T23:59:59.000Z

205

The prospects for polarized target materials with pure carbon background  

SciTech Connect (OSTI)

None of the materials presently in common use for polarized proton targets has a pure carbon nuclear background. The alcohols and diols contain some oxygen, and the ammonia and amine-based materials contain nitrogen and/or other noncarbon species. In the latter cases the noncarbon nuclei are measurably polarized as a concomitant of the process used to polarize the hydrogen nuclei. The relative simplicity of a pure carbon background would be advantageous for most types of scattering experiments and perhaps crucial for some. In addition to simplifying the kinematics of background events, pure carbon is relatively easy to prepare as a dummy'' target for background subtraction. Also, in such a target material, [sup 13]C-enrichment would yield a clean polarized [sup 13]C material. In this note I explore the possibilities for such materials, touching upon only what I consider to be the high'' points. The subject matter is capable of nearly endless ramification and speculation. In fact, owing to a general lack of relevant experimental data, even this relatively brief note contains much that is speculative to some degree.

Hill, D.A.

1992-10-06T23:59:59.000Z

206

Rev. January 30, 2012 1 REFERENCE and BACKGROUND CHECK  

E-Print Network [OSTI]

Rev. January 30, 2012 1 REFERENCE and BACKGROUND CHECK PROCESS HUMAN RESOURCES Workforce Planning, as allowed by law, and consistent with the job described. The appropriate Workforce Planning Analyst the documentation. (Please note that the review will take place in Human Resources, under a Workforce Planning

Eirinaki, Magdalini

207

Power Systems Engineering Research Center PSERC Background Paper  

E-Print Network [OSTI]

Power Systems Engineering Research Center PSERC Background Paper The New Electric Power Business-tuned, economically efficient, and technically-reliable electric power system. The creation of new information system is outmoded and unprepared for the challenges of the new electric power business. A result

208

Seeing is Believing: It's All About the Background  

E-Print Network [OSTI]

Seeing is Believing: It's All About the Background Thomas Meade Eileen Foell Chair in Cancer may promise for the experimental and clinical settings. Speaker Bio Thomas Meade, Ph.D., Received BS of Technology in the laboratory of Professor Harry B. Gray. In 1991 he joined the Division of Biology

Zanibbi, Richard

209

A method for enhancement of background sounds in forensic  

E-Print Network [OSTI]

A method for enhancement of background sounds in forensic audio recordings Robert C. Maher;Outline · Introduction ­ Audio forensic analysis ­ Adaptive interference cancelling ­ Sinusoidal modeling · Test implementation · Example processing · Conclusion #12;Audio Forensics · Audio Forensics

Maher, Robert C.

210

Neutrino interaction with background matter in a noninertial frame  

E-Print Network [OSTI]

We study Dirac neutrinos propagating in rotating background matter. First we derive the Dirac equation for a single massive neutrino in the noninertial frame, where matter is at rest. This equation is written in the effective curved space-time corresponding to the corotating frame. We find the exact solution of the Dirac equation. The neutrino energy levels for ultrarelativistic particles are obtained. Then we discuss several neutrino mass eigenstates, with a nonzero mixing between them, interacting with rotating background matter. We derive the effective Schr\\"{o}dinger equation governing neutrino flavor oscillations in rotating matter. The new resonance condition for neutrino oscillations is obtained. We also examine the correction to the resonance condition caused by the matter rotation.

Dvornikov, Maxim

2015-01-01T23:59:59.000Z

211

A robust algorithm for sky background computation in CCD images  

E-Print Network [OSTI]

In this paper we present a non-interactive algorithm to estimate a representative value for the sky background on CCD images. The method we have devised uses the mode as a robust estimator of the background brightness in sub-windows distributed across the input frame. The presence of contaminating objects is detected through the study of the local intensity distribution function and the perturbed areas are rejected using a statistical criterion which was derived from numerical simulations. The technique has been extensively tested on a large amount of images and it is suitable for fully automatic processing of large data volumes. The implementation we discuss here has been optimized for the ESO-FORS1 instrument, but it can be easily generalized to all CCD imagers with a sufficiently large field of view. The algorithm has been successfully used for the UBVRI ESO-Paranal night sky brightness survey (Patat 2003).

F. Patat

2003-01-27T23:59:59.000Z

212

Plane-parallel waves as duals of the flat background  

E-Print Network [OSTI]

We give a classification of non-Abelian T-duals of the flat metric in D=4 dimensions with respect to the four-dimensional continuous subgroups of the Poincare group. After dualizing the flat background, we identify majority of dual models as conformal sigma models in plane-parallel wave backgrounds, most of them having torsion. We give their form in Brinkmann coordinates. We find, besides the plane-parallel waves, several diagonalizable curved metrics with nontrivial scalar curvature and torsion. Using the non-Abelian T-duality, we find general solution of the classical field equations for all the sigma models in terms of d'Alembert solutions of the wave equation.

Ladislav Hlavaty; Ivo Petr

2014-12-03T23:59:59.000Z

213

What are the galaxies contributing to the Cosmic Infrared Background ?  

E-Print Network [OSTI]

Recent optical observations have led to a significant progress in our understanding of galaxy formation and evolution. However, our view on the deep universe is currently limited to the starlight which directly escapes from high-redshift galaxies, since we so far ignore the fraction of luminosity absorbed by dust and released in the IR/submm wavelength range. A new constraint is set by the possible detection of the Cosmic Infrared Background. We briefly review the observations and use a semi-analytic model of galaxy formation and evolution to predict number counts consistent with the level of the background. It turns out that the predictions fairly accomodate preliminary data at 175 and 850 microns. This suggests that a significant fraction of star/galaxy formation at high z is hidden by dust.

B. Guiderdoni

1997-12-29T23:59:59.000Z

214

Radon induced surface contaminations in low background experiments  

SciTech Connect (OSTI)

In neutrinoless double-beta decay and dark matter searches, one of the main issues is to increase the experimental sensitivity through careful material selection and production, minimizing the background contributions. In order to achieve the required, extremely low, counting rates, very stringent requirements must be fulfilled in terms of bulk material radiopurity. As the experimental sensitivity increases, the bulk impurities in the detector components decrease, and surface contaminations start to play an increasingly significant role In fully active detectors, like cryogenic particle detectors, surface contaminations are a critical issue (as shown by the CUORICINO experiment). {sup 222}Rn is by far the most intense source of airborne radioactivity, and if a radio-pure material is exposed to environment where the Radon concentration is not minimized, {sup 210}Pb and {sup 210}Po contaminations can occur. The mechanisms and the dynamics of Radon-induced surface contaminations are reviewed, and specific solutions to prevent and to reject the induced background are presented.

Pattavina, L. [INFN - Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy)] [INFN - Laboratori Nazionali del Gran Sasso, I-67010 Assergi (AQ) (Italy)

2013-08-08T23:59:59.000Z

215

Backgrounds of squeezed relic photons and their spatial correlations  

E-Print Network [OSTI]

We discuss the production of multi-photons squeezed states induced by the time variation of the (Abelian) gauge coupling constant in a string cosmological context. Within a fully quantum mechanical approach we solve the time evolution of the mean number of produced photons in terms of the squeezing parameters and in terms of the gauge coupling. We compute the first (amplitude interference) and second order (intensity interference) correlation functions of the magnetic part of the photon background. The photons produced thanks to the variation of the dilaton coupling are strongly bunched for the realistic case where the growth of the dilaton coupling is required to explain the presence of large scale magnetic fields and, possibly of a Faraday rotation of the Cosmic Microwave Background.

Massimo Giovannini

1999-08-19T23:59:59.000Z

216

Gravitational wave radiometry: Mapping a stochastic gravitational wave background  

SciTech Connect (OSTI)

The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either cosmological or astrophysical, bears a strong semblance to the analysis of the cosmic microwave background (CMB) anisotropy and polarization, which too is a stochastic field, statistically described in terms of its correlation properties. An astrophysical gravitational wave background (AGWB) will likely arise from an incoherent superposition of unmodelled and/or unresolved sources and cosmological gravitational wave backgrounds (CGWB) are also predicted in certain scenarios. The basic statistic we use is the cross correlation between the data from a pair of detectors. In order to ''point'' the pair of detectors at different locations one must suitably delay the signal by the amount it takes for the gravitational waves (GW) to travel to both detectors corresponding to a source direction. Then the raw (observed) sky map of the SGWB is the signal convolved with a beam response function that varies with location in the sky. We first present a thorough analytic understanding of the structure of the beam response function using an analytic approach employing the stationary phase approximation. The true sky map is obtained by numerically deconvolving the beam function in the integral (convolution) equation. We adopt the maximum likelihood framework to estimate the true sky map using the conjugate gradient method that has been successfully used in the broadly similar, well-studied CMB map-making problem. We numerically implement and demonstrate the method on signal generated by simulated (unpolarized) SGWB for the GW radiometer consisting of the LIGO pair of detectors at Hanford and Livingston. We include 'realistic' additive Gaussian noise in each data stream based on the LIGO-I noise power spectral density. The extension of the method to multiple baselines and polarized GWB is outlined. In the near future the network of GW detectors, including the Advanced LIGO and Virgo detectors that will be sensitive to sources within a thousand times larger spatial volume, could provide promising data sets for GW radiometry.

Mitra, Sanjit [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India); Observatoire de la Cote d'Azur, BP 4229, 06304 Nice Cedex 4 (France); Dhurandhar, Sanjeev; Souradeep, Tarun [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India); Lazzarini, Albert; Mandic, Vuk; Ballmer, Stefan [LIGO Laboratory, California Institute of Technology, MS 18-34, Pasadena, California 91125 (United States); Bose, Sukanta [Department of Physics, Washington State University, Pullman, Washington 99164-2814 (United States)

2008-02-15T23:59:59.000Z

217

Anisotropies in the gravitational-wave stochastic background  

SciTech Connect (OSTI)

We consider anisotropies in the stochastic background of gravitational-waves (SBGW) arising from random fluctuations in the number of gravitational-wave sources. We first develop the general formalism which can be applied to different cosmological or astrophysical scenarios. We then apply this formalism to calculate the anisotropies of SBGW associated with the fluctuations in the number of cosmic string loops, considering both cosmic string cusps and kinks. We calculate the anisotropies as a function of angle and frequency.

lmez, S.; Mandic, V. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Siemens, X., E-mail: olmez@physics.umn.edu, E-mail: mandic@physics.umn.edu, E-mail: siemens@gravity.phys.uwm.edu [Center for Gravitation and Cosmology, University of Wisconsin-Milwaukee, Milwaukee, WI 53201 (United States)

2012-07-01T23:59:59.000Z

218

RESOLVING THE RADIO SOURCE BACKGROUND: DEEPER UNDERSTANDING THROUGH CONFUSION  

SciTech Connect (OSTI)

We used the Karl G. Jansky Very Large Array to image one primary beam area at 3 GHz with 8'' FWHM resolution and 1.0 {mu}Jy beam{sup -1} rms noise near the pointing center. The P(D) distribution from the central 10 arcmin of this confusion-limited image constrains the count of discrete sources in the 1 < S({mu}Jy) < 10 range. At this level, the brightness-weighted differential count S {sup 2} n(S) is converging rapidly, as predicted by evolutionary models in which the faintest radio sources are star-forming galaxies; and Almost-Equal-To 96% of the background originating in galaxies has been resolved into discrete sources. About 63% of the radio background is produced by active galactic nuclei (AGNs), and the remaining 37% comes from star-forming galaxies that obey the far-infrared (FIR)/radio correlation and account for most of the FIR background at {lambda} Almost-Equal-To 160 {mu}m. Our new data confirm that radio sources powered by AGNs and star formation evolve at about the same rate, a result consistent with AGN feedback and the rough correlation of black hole and stellar masses. The confusion at centimeter wavelengths is low enough that neither the planned Square Kilometre Array nor its pathfinder ASKAP EMU survey should be confusion limited, and the ultimate source detection limit imposed by 'natural' confusion is {<=}0.01 {mu}Jy at {nu} = 1.4 GHz. If discrete sources dominate the bright extragalactic background reported by ARCADE 2 at 3.3 GHz, they cannot be located in or near galaxies and most are {<=}0.03 {mu}Jy at 1.4 GHz.

Condon, J. J.; Cotton, W. D.; Fomalont, E. B.; Kellermann, K. I. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Miller, N. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Perley, R. A. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Scott, D.; Vernstrom, T.; Wall, J. V. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1C1 (Canada)

2012-10-10T23:59:59.000Z

219

Detectability of Inflationary Gravitational Waves with Microwave Background Polarization  

E-Print Network [OSTI]

Inflation predicts specific relations between the amplitudes and spectral indices of the primordial spectrum of density (scalar metric) perturbations and gravitational waves (tensor metric perturbations). Detection of a stochastic gravitational-wave background is essential for identifying this unmistakable signature. Polarization of the cosmic microwave background can isolate these tensor modes in a model-independent way and thereby circumvent the cosmic-variance limit to detecting a small tensor signal with only a temperature map. Here we assess the detectability of a gravity-wave background with a temperature and polarization map. For detector sensitivities better than $10-20 \\mu K \\sqrt{sec}$, the sensitivity to a tensor signal is always dominated by the polarization map. With a detector sensitivity of order $1 \\mu K \\sqrt{sec}$, polarization could improve on a temperature-map sensitivity to tensor modes by two to three orders of magnitude. Even a small amount of reionization substantially enhances tensor-mode detectability. We also argue that the sensitivity of the Planck Surveyor to tensor modes is significantly improved with polarization, even taking into account the resulting degradation of the intensity determination in the high-frequency channels.

Marc Kamionkowski; Arthur Kosowsky

1997-05-28T23:59:59.000Z

220

Design Considerations for Large Mass Ultra-Low Background Experiments  

SciTech Connect (OSTI)

Summary The objective of this document is to present the designers of the next generation of large-mass, ultra-low background experiments with lessons learned and design strategies from previous experimental work. Design issues divided by topic into mechanical, thermal and electrical requirements are addressed. Large mass low-background experiments have been recognized by the scientific community as appropriate tools to aid in the refinement of the standard model. The design of these experiments is very costly and a rigorous engineering review is required for their success. The extreme conditions that the components of the experiment must withstand (heavy shielding, vacuum/pressure and temperature gradients), in combination with unprecedented noise levels, necessitate engineering guidance to support quality construction and safe operating conditions. Physical properties and analytical results of typical construction materials are presented. Design considerations for achieving ultra-low-noise data acquisition systems are addressed. Five large-mass, low-background conceptual designs for the one-tonne scale germanium experiment are proposed and analyzed. The result is a series of recommendations for future experiments engineering and for the Majorana simulation task group to evaluate the different design approaches.

Aguayo Navarrete, Estanislao; Reid, Douglas J.; Fast, James E.; Orrell, John L.

2011-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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221

Low-background tracker development for SuperNEMO  

SciTech Connect (OSTI)

The SuperNEMO experiment will search for neutrinoless double beta decay (0???) with a target sensitivity of T{sub 1/2}(0?) > 10{sup 26} years, corresponding to an effective neutrino mass of 50-100 meV. At its heart there is a low-background gaseous tracking detector which allows for extremely efficient background rejection and, if 0??? is observed, may provide important insights into the mechanism via which it may be mediated. Radon inside the tracker, which can mimic rare ?? events, is one of the most dangerous backgrounds for SuperNEMO. To reach the target sensitivity the radon concentration inside the tracking volume must be < 0.15 mBq/m{sup 3}. To reach this challengingly-low level of radon, a considerable program of R and D has been undertaken. This includes automation of the tracker-wiring process, development of a dedicated setup to measure radon diffusion and a 'radon concentration line' which will be able to measure levels of radon in the ?Bq/m{sup 3} range.

Mott, James [University College London, London, WC1E 6BT (United Kingdom)] [University College London, London, WC1E 6BT (United Kingdom); Collaboration: SuperNEMO Collaboration; and others

2013-08-08T23:59:59.000Z

222

Ultrarelativistic electron states in a general background electromagnetic field  

E-Print Network [OSTI]

The feasibility of obtaining exact analytical results in the realm of QED in the presence of a background electromagnetic field is almost exclusively limited to a few tractable cases, where the Dirac equation in the corresponding background field can be solved analytically. This circumstance has restricted, in particular, the theoretical analysis of QED processes in intense laser fields to within the plane-wave approximation even at those high intensities, achievable experimentally only by tightly focusing the laser energy in space. Here, within the Wentzel-Kramers-Brillouin (WKB) or eikonal approximation, we construct analytically single-particle electron states in the presence of a background electromagnetic field of general space-time structure in the realistic assumption that the initial energy of the electron is the largest dynamical energy scale in the problem. The relatively compact expression of these states opens, in particular, the possibility of investigating analytically strong-field QED processes in the presence of spatially focused laser beams, which is of particular relevance in view of the upcoming experimental campaigns in this field.

A. Di Piazza

2014-07-27T23:59:59.000Z

223

Problem Set 6 Assigned, Wednesday, March 26, 2014  

E-Print Network [OSTI]

: #12; 05.Foreground|10)A(IPr , 2.Foreground|30)A(IPr , 3.Foreground|40)A(IPr . and 3.Background|10)A(IPr , 1.Background|30)A(IPr , 05.Background|40)A(IPr . Draw a graph that the graph cut

Jacobs, David

224

Real-Time Active Cosmic Neutron Background Reduction Methods  

SciTech Connect (OSTI)

Neutron counting using large arrays of pressurized 3He proportional counters from an aerial system or in a maritime environment suffers from the background counts from the primary cosmic neutrons and secondary neutrons caused by cosmic ray?induced mechanisms like spallation and charge-exchange reaction. This paper reports the work performed at the Remote Sensing LaboratoryAndrews (RSL-A) and results obtained when using two different methods to reduce the cosmic neutron background in real time. Both methods used shielding materials with a high concentration (up to 30% by weight) of neutron-absorbing materials, such as natural boron, to remove the low-energy neutron flux from the cosmic background as the first step of the background reduction process. Our first method was to design, prototype, and test an up-looking plastic scintillator (BC-400, manufactured by Saint Gobain Corporation) to tag the cosmic neutrons and then create a logic pulse of a fixed time duration (~120 ?s) to block the data taken by the neutron counter (pressurized 3He tubes running in a proportional counter mode). The second method examined the time correlation between the arrival of two successive neutron signals to the counting array and calculated the excess of variance (Feynman variance Y2F)1 in the neutron count distribution from Poisson distribution. The dilution of this variance from cosmic background values ideally would signal the presence of man-made neutrons.2 The first method has been technically successful in tagging the neutrons in the cosmic-ray flux and preventing them from being counted in the 3He tube array by electronic vetofield measurement work shows the efficiency of the electronic veto counter to be about 87%. The second method has successfully derived an empirical relationship between the percentile non-cosmic component in a neutron flux and the Y2F of the measured neutron count distribution. By using shielding materials alone, approximately 55% of the neutron flux from man-made sources like 252Cf or Am-Be was removed.

Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ronald; Mitchell, Stephen; Guss, Paul

2013-09-01T23:59:59.000Z

225

pn-CCDs in a Low-Background Environment: Detector Background of the CAST X-ray Telescope  

E-Print Network [OSTI]

The CAST experiment at CERN (European Organization of Nuclear Research) searches for axions from the sun. The axion is a pseudoscalar particle that was motivated by theory thirty years ago, with the intention to solve the strong CP problem. Together with the neutralino, the axion is one of the most promising dark matter candidates. The CAST experiment has been taking data during the last two years, setting an upper limit on the coupling of axions to photons more restrictive than from any other solar axion search in the mass range below 0.1 eV. In 2005 CAST will enter a new experimental phase extending the sensitivity of the experiment to higher axion masses. The CAST experiment strongly profits from technology developed for high energy physics and for X-ray astronomy: A superconducting prototype LHC magnet is used to convert potential axions to detectable X-rays in the 1-10 keV range via the inverse Primakoff effect. The most sensitive detector system of CAST is a spin-off from space technology, a Wolter I type X-ray optics in combination with a prototype pn-CCD developed for ESA's XMM-Newton mission. As in other rare event searches, background suppression and a thorough shielding concept is essential to improve the sensitivity of the experiment to the best possible. In this context CAST offers the opportunity to study the background of pn-CCDs and its long term behavior in a terrestrial environment with possible implications for future space applications. We will present a systematic study of the detector background of the pn-CCD of CAST based on the data acquired since 2002 including preliminary results of our background simulations.

M. Kuster; S. Cebrian; A. Rodriquez; R. Kotthaus; H. Braeuninger; J. Franz; P. Friedrich; R. Hartmann; D. Kang; G. Lutz; L. Strueder

2005-08-10T23:59:59.000Z

226

Instructions to obtain the FBI background check Long-Stay Valencia Students The FBI Background Check is the first step in a two-part process. The FBI Background Check takes 4-6  

E-Print Network [OSTI]

Instructions to obtain the FBI background check Long-Stay Valencia Students The FBI Background Check is the first step in a two-part process. The FBI Background Check takes 4-6 weeks for processing form, fingerprint card and payment--to the following address: FBI CJIS Division Record Request 1000

Hull, Elaine

227

Pairs Emission in a Uniform Background Field: an Algebraic Approach  

E-Print Network [OSTI]

A fully algebraic general approach is developed to treat the pairs emission and absorption in the presence of some uniform external background field. In particular, it is shown that the pairs production and annihilation operators, together with the pairs number operator, do actually fulfill the SU(2) functional Lie algebra. As an example of application, the celebrated Schwinger formula is consistently and nicely recovered, within this novel approach, for a Dirac spinor field in the presence of a constant and homogeneous electric field in four spacetime dimensions.

Roberto Soldati

2011-06-23T23:59:59.000Z

228

Translational invariance and the anisotropy of the cosmic microwave background  

SciTech Connect (OSTI)

Primordial quantum fluctuations produced by inflation are conventionally assumed to be statistically homogeneous, a consequence of translational invariance. In this paper we quantify the potentially observable effects of a small violation of translational invariance during inflation, as characterized by the presence of a preferred point, line, or plane. We explore the imprint such a violation would leave on the cosmic microwave background anisotropy, and provide explicit formulas for the expected amplitudes of the spherical-harmonic coefficients.

Carroll, Sean M.; Tseng, C.-Y.; Wise, Mark B. [California Institute of Technology, Pasadena, California 91125 (United States)

2010-04-15T23:59:59.000Z

229

Technical background document for draft soil screening level guidance  

SciTech Connect (OSTI)

The document provides technical details of the derivation of the September 30, 1993, draft Soil Screening Levels (SSLs) Guidance for Superfund (PB93-963508). The document is presented in two sections. Section I defines SSL and provides background information on the development of SSLs and their application and implementation at Superfund sites, including sampling schemes for measuring SSL attainment. It also provides draft SSLs developed for 30 chemicals. Section II provides the technical basis for the development of SSLs addressing direct ingestion of soil, inhalation of volatiles and fugitive dust, and the soil-to-ground-water exposure pathway, including the assumptions and theories used the their development.

Not Available

1994-03-01T23:59:59.000Z

230

A low-neutron background slow-positron source.  

SciTech Connect (OSTI)

The addition of a thermionic rf gun [1] and a photocathode rf gun will allow the Advanced Photon Source (APS) linear accelerator (linac) [2] [3] to become a free-electron laser (FEL) driver [4]. As the FEL project progresses, the existing high-charge DC thermionic gun will no longer be critical to APS operation and could be used to generate high-energy or low-energy electrons to drive a slow-positron source. We investigated possibilities to create a useful low-energy source that could operate semi-independently and would have a low neutron background.

White, M. M.

1998-10-09T23:59:59.000Z

231

Collapsing Inhomogeneous Dust Fluid in the Background of Dark Energy  

E-Print Network [OSTI]

In the present work, gravitational collapse of an inhomogeneous spherical star model, consisting of inhomogeneous dust fluid (dark matter) in the background of dark energy is considered. The collapsing process is examined first separately for both dark matter and dark energy and then under the combined effect of dark matter and dark energy with or without interaction. The dark energy is considered in the form of perfect fluid and both marginally and non-marginally bound cases are considered for the collapsing model. Finally dark energy in the form of anisotropic fluid is investigated and it is found to be similar to ref. [12

Tanwi Bandyopadhyay; Subenoy Chakraborty

2006-05-11T23:59:59.000Z

232

Accretion onto a black hole in a string cloud background  

E-Print Network [OSTI]

We examine the accretion process onto the black hole with a string cloud background, where the horizon of the black hole has an enlarged radius $r_H=2 M/(1-\\alpha)$, due to the string cloud parameter $\\alpha\\; (0 \\leq \\alpha cloud parameter $\\alpha$. We also find the gas compression ratios and temperature profiles below the accretion radius and at the event horizon. It is shown that the mass accretion rate, for both the relativistic and the non-relativistic fluid by a black hole in the string cloud model, increases with increase in $\\alpha$.

Apratim Ganguly; Sushant G. Ghosh; Sunil D. Maharaj

2014-09-28T23:59:59.000Z

233

Muon-Induced Background Study for Underground Laboratories  

E-Print Network [OSTI]

We provide a comprehensive study of the cosmic-ray muon flux and induced activity as a function of overburden along with a convenient parameterization of the salient fluxes and differential distributions for a suite of underground laboratories ranging in depth from $\\sim$1 to 8 km.w.e.. Particular attention is given to the muon-induced fast neutron activity for the underground sites and we develop a Depth-Sensitivity-Relation to characterize the effect of such background in experiments searching for WIMP dark matter and neutrinoless double beta decay.

D. -M. Mei; A. Hime

2005-12-06T23:59:59.000Z

234

Stochastic background of gravitational waves from cosmological sources  

E-Print Network [OSTI]

Gravitational waves (GW) can constitute a unique probe of the primordial universe. In many cases, the characteristic frequency of the emitted GW is directly related to the energy scale at which the GW source is operating in the early universe. Consequently, different GW detectors can probe different energy scales in the evolution of the universe. After a general introduction on the properties of a GW stochastic background of primordial origin, some examples of cosmological sources are presented, which may lead to observable GW signals.

Caprini, Chiara

2015-01-01T23:59:59.000Z

235

Tree level Leptogenesis from Kalb-Ramond Torsion Background  

E-Print Network [OSTI]

The effect of torsion in theories of quantum gravity is known to be well described by an axion-like field which couples to matter as well as to gravitation and radiation gauge fields. In this note we consider a particular kind of torsion, arising from the Kalb-Ramond antisymmetric tensor field that appears in the gravitational multiplet of string theory. We investigate the implications for leptogenesis. It is shown that leptogenesis can occur even at tree-level and with only one generation of right-handed Majorana neutrinos, due to CP and CPT violation introduced by the background geometry.

M. de Cesare; Nick E. Mavromatos; Sarben Sarkar

2015-02-03T23:59:59.000Z

236

Measurements of Worldwide Radioxenon Backgrounds - The "EU" Project  

SciTech Connect (OSTI)

Under the Comprehensive Nuclear-Test-Ban Treaty (CTBT), radioactive xenon (radioxenon) measurements are one of the principle techniques used to detect nuclear underground nuclear explosions, and specifically, the presence of one or more radioxenon isotopes allows one to determine whether a suspected event was a nuclear explosion or originated from an innocent source. During the design of the International Monitoring System (IMS), which was designed as the verification mechanism for the Treaty, it was determined that radioxenon measurements should be performed at 40 or more stations worldwide. At the time of the design of the IMS, however, very few details about the background of the xenon isotopes was known and it is now recognized that the backgrounds were probably evolving anyhow. This paper lays out the beginning of a study of the worldwide concentrations of xenon isotopes that can be used to detect nuclear explosions and several sources that also release radioxenons, and will have to be accounted for during analysis of atmospheric levels. Although the global concentrations of the xenon isotopes are the scope of a much larger activity that could span over several years, this study measures radioxenon concentrations in locations where there was either very little information or there was a unique opportunity to learn more about emissions from known sources. The locations where radioxenon levels were measured and reported are included.

Bowyer, Ted W.; Cooper, Matthew W.; Hayes, James C.; Forrester, Joel B.; Haas, Derek A.; Hansen, Randy R.; Keller, Paul E.; Kirkham, Randy R.; Lidey, Lance S.; McIntyre, Justin I.; Miley, Harry S.; Payne, Rosara F.; Saey, Paul R.; Thompson, Robert C.; Woods, Vincent T.; Williams, Richard M.

2009-09-24T23:59:59.000Z

237

Large-Angular-Scale Anisotropy in the Cosmic Background Radiation  

DOE R&D Accomplishments [OSTI]

We report the results of an extended series of airborne measurements of large-angular-scale anisotropy in the 3 K cosmic background radiation. Observations were carried out with a dual-antenna microwave radiometer operating at 33 GHz (.089 cm wavelength) flown on board a U-2 aircraft to 20 km altitude. In eleven flights, between December 1976 and May 1978, the radiometer measured differential intensity between pairs of directions distributed over most of the northern hemisphere with an rms sensitivity of 47 mK Hz{sup 1?}. The measurements how clear evidence of anisotropy that is readily interpreted as due to the solar motion relative to the sources of the radiation. The anisotropy is well fit by a first order spherical harmonic of amplitude 360{+ or -}50km sec{sup -1} toward the direction 11.2{+ or -}0.5 hours of right ascension and 19 {+ or -}8 degrees declination. A simultaneous fit to a combined hypotheses of dipole and quadrupole angular distributions places a 1 mK limit on the amplitude of most components of quadrupole anisotropy with 90% confidence. Additional analysis places a 0.5 mK limit on uncorrelated fluctuations (sky-roughness) in the 3 K background on an angular scale of the antenna beam width, about 7 degrees.

Gorenstein, M. V.; Smoot, G. F.

1980-05-00T23:59:59.000Z

238

THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE LOW RESOLUTION SPECTROMETER  

SciTech Connect (OSTI)

Absolute spectrophotometric measurements of diffuse radiation at 1 {mu}m to 2 {mu}m are crucial to our understanding of the radiative content of the universe from nucleosynthesis since the epoch of reionization, the composition and structure of the zodiacal dust cloud in our solar system, and the diffuse galactic light arising from starlight scattered by interstellar dust. The Low Resolution Spectrometer (LRS) on the rocket-borne Cosmic Infrared Background Experiment is a {lambda}/{Delta}{lambda} {approx} 15-30 absolute spectrophotometer designed to make precision measurements of the absolute near-infrared sky brightness between 0.75 {mu}m <{lambda} < 2.1 {mu}m. This paper presents the optical, mechanical, and electronic design of the LRS, as well as the ground testing, characterization, and calibration measurements undertaken before flight to verify its performance. The LRS is shown to work to specifications, achieving the necessary optical and sensitivity performance. We describe our understanding and control of sources of systematic error for absolute photometry of the near-infrared extragalactic background light.

Tsumura, K.; Arai, T.; Matsumoto, T.; Matsuura, S.; Murata, K. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronoutical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Battle, J.; Bock, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Brown, S.; Lykke, K.; Smith, A. [Optical Technology Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899 (United States); Cooray, A. [Center for Cosmology, University of California, Irvine, Irvine, CA 92697 (United States); Hristov, V.; Levenson, L. R.; Mason, P. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Keating, B.; Renbarger, T. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H.; Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Sullivan, I., E-mail: tsumura@ir.isas.jaxa.jp [Department of Physics, The University of Washington, Seattle, WA 98195 (United States); and others

2013-08-15T23:59:59.000Z

239

COMPONENTS OF THE EXTRAGALACTIC GAMMA-RAY BACKGROUND  

SciTech Connect (OSTI)

We present new theoretical estimates of the relative contributions of unresolved blazars and star-forming galaxies to the extragalactic {gamma}-ray background (EGB) and discuss constraints on the contributions from alternative mechanisms such as dark matter annihilation and truly diffuse {gamma}-ray production. We find that the Fermi source count data do not rule out a scenario in which the EGB is dominated by emission from unresolved blazars, though unresolved star-forming galaxies may also contribute significantly to the background, within order-of-magnitude uncertainties. In addition, we find that the spectrum of the unresolved star-forming galaxy contribution cannot explain the EGB spectrum found by EGRET at energies between 50 and 200 MeV, whereas the spectrum of unresolved flat spectrum radio quasars, when accounting for the energy-dependent effects of source confusion, could be consistent with the combined spectrum of the low-energy EGRET EGB measurements and the Fermi-Large Area Telescope EGB measurements.

Stecker, Floyd W. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Venters, Tonia M., E-mail: floyd.w.stecker@nasa.gov [Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2011-07-20T23:59:59.000Z

240

10:30AM TODAY: Senior Administration Officials to Hold a Background...  

Office of Environmental Management (EM)

TODAY: Senior Administration Officials to Hold a Background Conference Call Regarding Oil 10:30AM TODAY: Senior Administration Officials to Hold a Background Conference Call...

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Electromagnetic radiation in a time-varying background medium  

E-Print Network [OSTI]

Analytical solutions are presented for the electromagnetic radiation by an arbitrary pulsed source into a homogeneous time-varying background medium. In the constant-impedance case an explicit radiation formula is obtained for the synchronous permittivity and permeability described by any positive function of time. As might be expected, such a medium introduces significant spectral shifts and spatio-temporal modulation, which are analized here for the linear and exponential time-variations of the medium parameters. In the varying-impedance case the solution is obtained for the fourth-order polynomial time-dependence of the permittivity. In addition to the spectral shifts and modulation this spatially homogeneous medium scatters the field introducing causal echoes at the receiver location.

Budko, Neil V

2009-01-01T23:59:59.000Z

242

Radiation shielding for underground low-background experiments  

E-Print Network [OSTI]

The design task of creating an efficient radiation shield for the new COBRA double-beta decay experiment led to a comprehensive study of commercially available shielding materials. The aim was to find the most efficient combination of materials under the constraints of an extreme low-background experiment operating in a typical underground laboratory. All existing shield configurations for this type of experiment have been found to perform sub-optimally in comparison to the class of multilayered configurations proposed in this study. The method used here to create a specific shield configuration should yield a close to optimal result when applied to any experiment utilising a radiation shield. In particular, the survey of single material response to a given radiation source turns out to give a guideline for the construction of efficient multilayer shields.

D. Y Stewart; P. F. Harrison; B. Morgan; Y. A. Ramachers

2006-07-31T23:59:59.000Z

243

Evaluation of Background Mercury Concentrations in the SRS Groundwater System  

SciTech Connect (OSTI)

Mercury analyses associated with the A-01 Outfall have highlighted the importance of developing an understanding of mercury in the Savannah River Site groundwater system and associated surface water streams. This activity is critical based upon the fact that the EPA Ambient Water Quality Criteria (AWQC) for this constituent is 0.012mg/L, a level that is well below conventional detection limits of 0.1 to 0.2 mg/L. A first step in this process is obtained by utilizing the existing investment in groundwater mercury concentrations (20,242 records) maintained in the SRS geographical information management system (GIMS) database. Careful use of these data provides a technically defensible initial estimate for total recoverable mercury in background and contaminated SRS wells.

Looney, B.B.

1999-03-03T23:59:59.000Z

244

The colours of the X-ray background  

E-Print Network [OSTI]

The recent deep X-ray surveys at both soft (0.5--2 keV) and hard (2--10 keV) energies have greatly extended our knowledge of the X-ray source density and spectral shapes at relatively faint fluxes adding further evidence on the fact that discrete sources, mainly AGNs, are responsible for the X-ray background (XRB) emission over a broad energy range. In addition the first complete optically identified samples of soft X-ray sources are becoming available allowing to test the XRB AGN synthesis models in the light of recent results. In this paper I will briefly compare the model predictions with some new observational data.

A. Comastri

1998-09-07T23:59:59.000Z

245

Holographic non-Fermi liquid in a background magnetic field  

SciTech Connect (OSTI)

We study the effects of a nonzero magnetic field on a class of 2+1 dimensional non-Fermi liquids, recently found in [Hong Liu, John McGreevy, and David Vegh, arXiv:0903.2477.] by considering properties of a Fermionic probe in an extremal AdS{sup 4} black hole background. Introducing a similar fermionic probe in a dyonic AdS{sup 4} black hole geometry, we find that the effect of a magnetic field could be incorporated in a rescaling of the probe fermion's charge. From this simple fact, we observe interesting effects like gradual disappearance of the Fermi surface and quasiparticle peaks at large magnetic fields and changes in other properties of the system. We also find Landau level like structures and oscillatory phenomena similar to the de-Haas-van Alphen effect.

Basu, Pallab; He Jianyang; Mukherjee, Anindya; Shieh, Hsien-Hang [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, B.C. V6T 1Z1 (Canada)

2010-08-15T23:59:59.000Z

246

Weighing the Universe with the Cosmic Microwave Background  

E-Print Network [OSTI]

Variations in $\\Omega$, the total density of the Universe, leave a clear and distinctive imprint on the power spectrum of temperature fluctuations in the cosmic microwave background (CMB). This signature is virtually independent of other cosmological parameters or details of particular cosmological models. We evaluate the precision with which $\\Omega$ can be determined by a CMB map as a function of sky coverage, pixel noise, and beam size. For example, assuming only that the primordial density perturbations were adiabatic and with no prior information on the values of any other cosmological parameters, a full-sky CMB map at $0.5^\\circ$ angular resolution and a noise level of $15\\,\\mu{\\rm K}$ per pixel can determine $\\Omega$ with a variance of 5\\%. If all other cosmological parameters are fixed, $\\Omega$ can be measured to better than 1\\%.

Gerard Jungman; Marc Kamionkowski; Arthur Kosowsky; David N. Spergel

1995-07-21T23:59:59.000Z

247

Background-reducing X-ray multilayer mirror  

DOE Patents [OSTI]

Background-reducing x-ray multilayer mirror. A multiple-layer "wavetrap" deposited over the surface of a layered, synthetic-microstructure soft x-ray mirror optimized for reflectivity at chosen wavelengths is disclosed for reducing the reflectivity of undesired, longer wavelength incident radiation incident thereon. In three separate mirror designs employing an alternating molybdenum and silicon layered, mirrored structure overlaid by two layers of a molybdenum/silicon pair anti-reflection coating, reflectivities of near normal incidence 133, 171, and 186 .ANG. wavelengths have been optimized, while that at 304 .ANG. has been minimized. The optimization process involves the choice of materials, the composition of the layer/pairs as well as the number thereof, and the distance therebetween for the mirror, and the simultaneous choice of materials, the composition of the layer/pairs, and their number and distance for the "wavetrap."

Bloch, Jeffrey J. (Los Alamos, NM); Roussel-Dupre', Diane (Los Alamos, NM); Smith, Barham W. (Los Alamos, NM)

1992-01-01T23:59:59.000Z

248

Testing gaussianity, homogeneity and isotropy with the cosmic microwave background  

E-Print Network [OSTI]

We review the basic hypotheses which motivate the statistical framework used to analyze the cosmic microwave background, and how that framework can be enlarged as we relax those hypotheses. In particular, we try to separate as much as possible the questions of gaussianity, homogeneity and isotropy from each other. We focus both on isotropic estimators of non-gaussianity as well as statistically anisotropic estimators of gaussianity, giving particular emphasis on their signatures and the enhanced "cosmic variances" that become increasingly important as our putative Universe becomes less symmetric. After reviewing the formalism behind some simple model-independent tests, we discuss how these tests can be applied to CMB data when searching for large scale "anomalies"

L. Raul Abramo; Thiago S. Pereira

2010-05-13T23:59:59.000Z

249

Separating Signal From Background Using Ensembles of Rules  

SciTech Connect (OSTI)

Machine learning has emerged as a important tool for separating signal events from associated background in high energy particle physics experiments. This paper describes a new machine learning method based on ensembles of rules. Each rule consists of a conjuction of a small number of simple statements (''cuts'') concerning the values of individual input variables. These rule ensembles produce predictive accuracy comparable to the best methods. However their principal advantage lies in interpretation. Because of its simple form, each rule is easy to understand, as is its influence on the predictive model. Similarly, the degree of relevance of each of the respective input variables can be assessed. Graphical representations are presented that can be used to ascertain the dependence of the model jointly on the variables used for prediction.

Friedman, J.H.; /SLAC /Stanford U., Phys. Dept.

2006-12-01T23:59:59.000Z

250

Injection Related Background due to the Transverse Feedback  

SciTech Connect (OSTI)

The background in the BaBar detector is especially high during injection, when most components are actually having reduced voltages. The situation is worse for the beam in High Energy Ring (HER) when the LER beam is present. It was found that the transverse feedback system plays an important role when stacking more charge on top of existing bunches. Lowering the feedback gain helped and it was realized later that the best scenario would be to gate off the feedback for only the one bunch, which got additional charge injected into it. The explanation is that the blown-up, but centered, original HER bunch plus the small injected off-axis bunch (each with half the charge) would stay in the ring if not touched, but the feedback system sees half the offset and wants to correct it, therefore disturbing and scraping the blown-up part.

Decker, F.J.; Akre, R.; Fisher, A.; Iverson, R.; Weaver, M.; /SLAC

2008-03-18T23:59:59.000Z

251

Gravitational wave background from Standard Model physics: Qualitative features  

E-Print Network [OSTI]

Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at T > 160 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future ge...

Ghiglieri, J

2015-01-01T23:59:59.000Z

252

B2FH, the Cosmic Microwave Background and Cosmology  

E-Print Network [OSTI]

In this talk I shall start by describing how we set about and carried out the work which led to the publication of B2FH in 1957. I then shall try and relate this work and the circumstances that surrounded it to the larger problem of the origin and formation of the universe. Here it is necessary to look back at the way that ideas developed and how in many situations astronomers went astray. Of course this is a personal view, though I very strongly believe that if he were still here, it is the approach that Fred Hoyle would take. I start by describing the problems originally encountered by Gamow and his associates in trying to decide where the helium was made. This leads me to a modern discussion of the origin of 2D, 3He, 4He and 7Li, originally described by B2FH as due to the x-process. While it is generally argued, following Gamow, Alpher, and Herman, that these isotopes were synthesized in a big bang I shall show that it is equally likely that these isotopes were made in active galactic nuclei, as was the cosmic microwave background (CMB), in a cyclic universe model. The key piece of observational evidence is that the amount of energy carried by the CMB, namely about 4.5 x 10-13 erg cm-3

G. Burbidge

2008-07-24T23:59:59.000Z

253

Project Lyman: Quantifying 11 Gyrs of Metagalactic Ionizing Background Evolution  

E-Print Network [OSTI]

The timing and duration of the reionization epoch is crucial to the emergence and evolution of structure in the universe. The relative roles that star-forming galaxies, active galactic nuclei and quasars play in contributing to the metagalactic ionizing background across cosmic time remains uncertain. Deep quasar counts provide insights into their role, but the potentially crucial contribution from star-formation is highly uncertain due to our poor understanding of the processes that allow ionizing radiation to escape into the intergalactic medium (IGM). The fraction of ionizing photons that escape from star-forming galaxies is a fundamental free parameter used in models to "fine-tune" the timing and duration of the reionization epoch that occurred somewhere between 13.4 and 12.7 Gyrs ago (redshifts between 12 > z > 6). However, direct observation of Lyman continuum (LyC) photons emitted below the rest frame \\ion{H}{1} ionization edge at 912 \\AA\\ is increasingly improbable at redshifts z > 3, due to the stead...

McCandliss, Stephan R; Bergvall, Nils; Bianchi, Luciana; Bridge, Carrie; Bogosavljevic, Milan; Cohen, Seth H; Deharveng, Jean-Michel; Dixon, W Van Dyke; Ferguson, Harry; Friedman, Peter; Hayes, Matthew; Howk, J Christopher; Inoue, Akio; Iwata, Ikuru; Kaiser, Mary Elizabeth; Kriss, Gerard; Kruk, Jeffrey; Kutyrev, Alexander S; Leitherer, Claus; Meurer, Gerhardt R; Prochaska, Jason X; Sonneborn, George; Stiavelli, Massimo; Teplitz, Harry I; Windhorst, Rogier A

2012-01-01T23:59:59.000Z

254

Kinematics of geodesic flows in stringy black hole backgrounds  

E-Print Network [OSTI]

We study the kinematics of timelike geodesic congruences in two and four dimensions in spacetime geometries representing stringy black holes. The Raychaudhuri equations for the kinematical quantities (namely, expansion, shear and rotation) characterising such geodesic flows are written down and subsequently solved analytically (in two dimensions) and numerically (in four dimensions) for specific geodesics flows. We compare between geodesic flows in dual (electric and magnetic) stringy black hole backgrounds in four dimensions, by showing the differences that arise in the corresponding evolutions of the kinematic variables. The crucial role of initial conditions and the spacetime curvature on the evolution of the kinematical variables is illustrated. Some novel general conclusions on geodesic focusing are obtained from the analytical and numerical findings. We also propose new quantifiers in terms of (a) the time (affine parameter) of approach to a singularity and (b) the location of extrema in the functional evolution of the kinematic variables, which may be used to distinguish between flows in different geometries. In summary, our quantitative findings bring out hitherto unknown features of the kinematics of geodesic flows, which, otherwise, would have remained overlooked, if we confined ourselves to only a qualitative analysis.

Anirvan Dasgupta; Hemwati Nandan; Sayan Kar

2009-06-12T23:59:59.000Z

255

Reissner-Nordstrom black hole in dark energy background  

E-Print Network [OSTI]

In this paper we propose a stationary solution of Einstein's field equations describing Reissner-Nordstrom black hole in dark energy background. It is to be regarded as the Reissner-Nordstrom black hole is embedded into the dark energy solution producing Reissner-Nordstrom-dark energy black hole. We find that the space-time geometry of Reissner-Nordstrom-dark energy solution is Petrov type $D$ in the classification of space-times. It is also shown that the embedded space-time possesses an energy-momentum tensor of the electromagnetic field interacting with the dark energy having negative pressure. We find the energy-momentum tensor for dark energy violates the the strong energy condition due to the negative pressure, whereas that of the electromagnetic field obeys the strong energy condition. It is shown that the time-like vector field for an observer in the Reissner-Nordstrom-dark energy space is expanding, accelerating, shearing and non-rotating. We investigate the surface gravity of the horizons for the embedded dark energy black hole. The characteristic properties of relativistic dark energy based on the de Sitter solution is discussed in an appendix.

Ngangbam Ishwarchandra; Ng. Ibohal; K. Yugindro Singh

2014-11-29T23:59:59.000Z

256

Cosmological-Parameter Determination with Microwave Background Maps  

E-Print Network [OSTI]

The angular power spectrum of the cosmic microwave background (CMB) contains information on virtually all cosmological parameters of interest, including the geometry of the Universe ($\\Omega$), the baryon density, the Hubble constant ($h$), the cosmological constant ($\\Lambda$), the number of light neutrinos, the ionization history, and the amplitudes and spectral indices of the primordial scalar and tensor perturbation spectra. We review the imprint of each parameter on the CMB. Assuming only that the primordial perturbations were adiabatic, we use a covariance-matrix approach to estimate the precision with which these parameters can be determined by a CMB temperature map as a function of the fraction of sky mapped, the level of pixel noise, and the angular resolution. For example, with no prior information about any of the cosmological parameters, a full-sky CMB map with $0.5^\\circ$ angular resolution and a noise level of 15 $\\mu$K per pixel can determine $\\Omega$, $h$, and $\\Lambda$ with standard errors of $\\pm0.1$ or better, and provide determinations of other parameters which are inaccessible with traditional observations. Smaller beam sizes or prior information on some of the other parameters from other observations improves the sensitivity. The dependence on the the underlying cosmological model is discussed.

Gerard Jungman; Marc Kamionkowski; Arthur Kosowsky; David N. Spergel

1996-05-23T23:59:59.000Z

257

Delensing the CMB with the Cosmic Infrared Background  

E-Print Network [OSTI]

As confusion with lensing B-modes begins to limit experiments that search for primordial B-mode polarization, robust methods for delensing the CMB polarization sky are becoming increasingly important. We investigate in detail the possibility of delensing the CMB with the cosmic infrared background (CIB), emission from dusty star-forming galaxies that is an excellent tracer of the CMB lensing signal, in order to improve constraints on the tensor-to-scalar ratio $r$. We find that the maps of the CIB, such as current Planck satellite maps at 545 GHz, can be used to remove more than half of the lensing B-mode power. Calculating optimal combinations of different large-scale-structure tracers for delensing, we find that co-adding CIB data and external arcminute-resolution CMB lensing reconstruction can lead to significant additional improvements in delensing performance. We investigate whether measurement uncertainty in the CIB spectra will degrade the delensing performance if no model of the CIB spectra is assumed...

Sherwin, Blake D

2015-01-01T23:59:59.000Z

258

Dusty Infrared Galaxies: Sources of the Cosmic Infrared Background  

E-Print Network [OSTI]

The discovery of the Cosmic Infrared Background (CIB) in 1996, together with recent cosmological surveys from the mid-infrared to the millimeter have revolutionized our view of star formation at high redshifts. It has become clear, in the last decade, that a population of galaxies that radiate most of their power in the far-infrared (the so-called ``infrared galaxies'') contributes an important part of the whole galaxy build-up in the Universe. Since 1996, detailed (and often painful) investigations of the high-redshift infrared galaxies have resulted in the spectacular progress covered in this review. We outline the nature of the sources of the CIB including their star-formation rate, stellar and total mass, morphology, metallicity and clustering properties. We discuss their contribution to the stellar content of the Universe and their origin in the framework of the hierarchical growth of structures. We finally discuss open questions for a scenario of their evolution up to the present-day galaxies.

Guilaine Lagache; Jean-Loup Puget; Herve Dole

2005-07-12T23:59:59.000Z

259

Optical emission line monitor with background observation and cancellation  

DOE Patents [OSTI]

A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium D-line emission in coal combustion, may be detected in the presence of interferring background or blackbody radiation with emissions much greater in intensity than that of the emission line being detected. A bifurcated fiber optic light guide is adapted at the end of one branch to view the combustion light which is guided to a first bandpass filter, adapted to the common trunk end of the fiber. A portion of the light is reflected back through the common trunk portion of the fiber to a second bandpass filter adapted to the end of the other branch of the fiber. The first filter bandpass is centered at a wavelength corresponding to the emission line to be detected with a bandwidth of about three nanometers (nm). The second filter is centered at the same wavelength but having a width of about 10 nm. First and second light detectors are located to view the light passing through the first and second filters respectively. Thus, the second detector is blind to the light corresponding to the emission line of interest detected by the first detector and the difference between the two detector outputs is uniquely indicative of the intensity of only the combustion flame emission of interest. This instrument can reduce the effects of interferring blackbody radiation by greater than 20 dB.

Goff, David R. (Star City, WV); Notestein, John E. (Morgantown, WV)

1986-01-01T23:59:59.000Z

260

Optical emission line monitor with background observation and cancellation  

DOE Patents [OSTI]

A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium D-line emission in coal combustion, may be detected in the presence of interferring background or blackbody radiation with emissions much greater in intensity than that of the emission line being detected. A bifurcated fiber optic light guide is adapted at the end of one branch to view the combustion light which is guided to a first bandpass filter, adapted to the common trunk end of the fiber. A portion of the light is reflected back through the common trunk portion of the fiber to a second bandpass filter adapted to the end of the other branch of the fiber. The first filter bandpass is centered at a wavelength corresponding to the emission line to be detected with a bandwidth of about three nanometers (nm). The second filter is centered at the same wavelength but having a width of about 10 nm. First and second light detectors are located to view the light passing through the first and second filters respectively. Thus, the second detector is blind to the light corresponding to the emission line of interest detected by the first detector and the difference between the two detector outputs is uniquely indicative of the intensity of only the combustion flame emission of interest. This instrument can reduce the effects of interfering blackbody radiation by greater than 20 dB.

Goff, D.R.; Notestein, J.E.

1985-01-04T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
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261

The companion candidate near Fomalhaut - a background neutron star?  

E-Print Network [OSTI]

The directly detected planetary mass companion candidate close to the young, nearby star Fomalhaut is a subject of intense discussion. While the detection of common proper motion led to the interpretation as Jovian-mass companion, later non-detections in the infrared raised doubts. Recent astrometric measurements indicate a belt crossing or highly eccentric orbit for the object, if a companion, making the planetary interpretation potentially even more problematic. In this study we discuss the possibility of Fomalhaut\\,b being a background object with a high proper motion. By analysing the available photometric and astrometric data of the object, we show that they are fully consistent with a neutron star: Neutron stars are faint, hot (blue), and fast moving. Neutron stars with an effective temperature of the whole surface area being 112,000 K to 126,500 K (with small to negligible extinction) at a distance of roughly 11 pc (best fit) would be consistent with all observables, namely with the photometric detecti...

Neuhaeuser, Ralph; Ginski, Christian; Schmidt, Janos; Hambaryan, Valeri; Schmidt, Tobias

2015-01-01T23:59:59.000Z

262

Binary electrokinetic separation of target DNA from background DNA primers.  

SciTech Connect (OSTI)

This report contains the summary of LDRD project 91312, titled ''Binary Electrokinetic Separation of Target DNA from Background DNA Primers''. This work is the first product of a collaboration with Columbia University and the Northeast BioDefense Center of Excellence. In conjunction with Ian Lipkin's lab, we are developing a technique to reduce false positive events, due to the detection of unhybridized reporter molecules, in a sensitive and multiplexed detection scheme for nucleic acids developed by the Lipkin lab. This is the most significant problem in the operation of their capability. As they are developing the tools for rapidly detecting the entire panel of hemorrhagic fevers this technology will immediately serve an important national need. The goal of this work was to attempt to separate nucleic acid from a preprocessed sample. We demonstrated the preconcentration of kilobase-pair length double-stranded DNA targets, and observed little preconcentration of 60 base-pair length single-stranded DNA probes. These objectives were accomplished in microdevice formats that are compatible with larger detection systems for sample pre-processing. Combined with Columbia's expertise, this technology would enable a unique, fast, and potentially compact method for detecting/identifying genetically-modified organisms and multiplexed rapid nucleic acid identification. Another competing approach is the DARPA funded IRIS Pharmaceutical TIGER platform which requires many hours for operation, and an 800k$ piece of equipment that fills a room. The Columbia/SNL system could provide a result in 30 minutes, at the cost of a few thousand dollars for the platform, and would be the size of a shoebox or smaller.

James, Conrad D.; Derzon, Mark Steven

2005-10-01T23:59:59.000Z

263

Directions to the Social Security Office 135 Beaver Street, Waltham  

E-Print Network [OSTI]

://www.brandeis.edu/publicsafety/safety/escort/schedule.html) 2. Take Bus 554 towards Waverly via Newton Corner & Mass. Pike (see schedule and fares at www.mbta

Fraden, Seth

264

Beaver City Corporation (Utility Company) | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of Inspector GeneralDepartmentAUDIT REPORTOpenWendeGuo Feng Bio JumpVentures Jump to:City Corporation (Utility

265

Beaver County, Oklahoma: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160 EastMaine:Barbers PointEnergy Information Hot Springs

266

Beaver County, Pennsylvania: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160 EastMaine:Barbers PointEnergy Information Hot SpringsInformation

267

Beaver County, Utah: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160 EastMaine:Barbers PointEnergy Information HotUtah: Energy Resources Jump to:

268

Beaver Cove, Maine: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160 EastMaine:Barbers PointEnergy Information HotUtah: Energy Resources Jump

269

Beaver Creek, Minnesota: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160 EastMaine:Barbers PointEnergy Information HotUtah: Energy Resources JumpCreek,

270

Boralex Beaver Livermore Falls Biomass Facility | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of InspectorConcentrating SolarElectricEnergyCTBarre BiomassTHIS PAGE ISJumpSphereBonitaBooleanElectricLivermore

271

Basin-Scale Opportunity Assessment Initiative Background Literature Review  

SciTech Connect (OSTI)

As called for in the March 24, 2010, Memorandum of Understanding (MOU) for Hydropower, the U.S. Department of Energy (DOE), the U.S. Department of the Interior (DOI), the U.S. Army Corps of Engineers (USACE), environmental stakeholders, and the hydropower industry are collaborating to identify opportunities to simultaneously increase electricity generation and improve environmental services in river basins of the United States. New analytical tools provide an improved ability to understand, model, and visualize environmental and hydropower systems. Efficiencies and opportunities that might not be apparent in site-by-site analyses can be revealed through assessments at the river-basin scale. Information from basin-scale assessments could lead to better coordination of existing hydropower projects, or to inform siting decisions (e.g., balancing the removal of some dams with the construction of others), in order to meet renewable energy production and environmental goals. Basin-scale opportunity assessments would inform energy and environmental planning and address the cumulative effects of hydropower development and operations on river basin environmental quality in a way that quantifies energy-environment tradeoffs. Opportunity assessments would create information products, develop scenarios, and identify specific actions that agencies, developers, and stakeholders can take to locate new sustainable hydropower projects, increase the efficiency and environmental performance of existing projects, and restore and protect environmental quality in our nation's river basins. Government agencies and non-governmental organizations (NGO) have done significant work to understand and assess opportunities for both hydropower and environmental protection at the basin scale. Some initiatives have been successful, others less so, and there is a need to better understand the legacy of work on which this current project can build. This background literature review is intended to promote that understanding. The literature review begins with a discussion in Section 2.0 of the Federal regulatory processes and mission areas pertaining to hydropower siting and licensing at the basin scale. This discussion of regulatory processes and mission areas sets the context for the next topic in Section 3.0, past and ongoing basin-scale hydropower planning and assessment activities. The final sections of the literature review provide some conclusions about past and ongoing basin-scale activities and their relevance to the current basin-scale opportunity assessment (Section 4.0), and a bibliography of existing planning and assessment documents (Section 5.0).

Saulsbury, Bo [ORNL; Geerlofs, Simon H. [Pacific Northwest National Laboratory (PNNL); Cada, Glenn F [ORNL; Bevelhimer, Mark S [ORNL

2010-10-01T23:59:59.000Z

272

Non-linear evolution of the cosmic neutrino background  

SciTech Connect (OSTI)

We investigate the non-linear evolution of the relic cosmic neutrino background by running large box-size, high resolution N-body simulations which incorporate cold dark matter (CDM) and neutrinos as independent particle species. Our set of simulations explore the properties of neutrinos in a reference ?CDM model with total neutrino masses between 0.05-0.60 eV in cold dark matter haloes of mass 10{sup 11}?10{sup 15} h{sup ?1}M{sub s}un, over a redshift range z = 0?2. We compute the halo mass function and show that it is reasonably well fitted by the Sheth-Tormen formula, once the neutrino contribution to the total matter is removed. More importantly, we focus on the CDM and neutrino properties of the density and peculiar velocity fields in the cosmological volume, inside and in the outskirts of virialized haloes. The dynamical state of the neutrino particles depends strongly on their momentum: whereas neutrinos in the low velocity tail behave similarly to CDM particles, neutrinos in the high velocity tail are not affected by the clustering of the underlying CDM component. We find that the neutrino (linear) unperturbed momentum distribution is modified and mass and redshift dependent deviations from the expected Fermi-Dirac distribution are in place both in the cosmological volume and inside haloes. The neutrino density profiles around virialized haloes have been carefully investigated and a simple fitting formula is provided. The neutrino profile, unlike the cold dark matter one, is found to be cored with core size and central density that depend on the neutrino mass, redshift and mass of the halo, for halos of masses larger than ? 10{sup 13.5}h{sup ?1}M{sub s}un. For lower masses the neutrino profile is best fitted by a simple power-law relation in the range probed by the simulations. The results we obtain are numerically converged in terms of neutrino profiles at the 10% level for scales above ? 200 h{sup ?1}kpc at z = 0, and are stable with respect to box-size and starting redshift of the simulation. Our findings are particularly important in view of upcoming large-scale structure surveys, like Euclid, that are expected to probe the non-linear regime at the percent level with lensing and clustering observations.

Villaescusa-Navarro, Francisco; Viel, Matteo [INAF/Osservatorio Astronomico di Trieste, Via Tiepolo 11, 34143, Trieste (Italy); Bird, Simeon [Institute for Advanced Study, 1 Einstein Drive, Princeton, NJ, 08540 (United States); Pea-Garay, Carlos, E-mail: villaescusa@oats.inaf.it, E-mail: spb@ias.edu, E-mail: penya@ific.uv.es, E-mail: viel@oats.inaf.it [Instituto de Fsica Corpuscular, CSIC-UVEG, E-46071, Paterna, Valencia (Spain)

2013-03-01T23:59:59.000Z

273

Narrative Foreground in the Plays of Osvaldo Dragn  

E-Print Network [OSTI]

the audience is prepared for an experience of storytelling, that is, of narration. Robyn Lutz notes that "the consciousness of audience is always present, with the result that the tale never becomes a you-were-there reliving of past events" (31). David... Foster points out that the audience of Historias "proporciona tanto la sustancia semntica de la obra como su validacin lingstica en la medida en que el receptor justifica la presencia del mensaje" (134). The first story, "Historia de un flemn, una...

Gladhart, Amalia

1993-04-01T23:59:59.000Z

274

Background and Related Work Data Encoding for Failure-Prone Sensor Networks  

E-Print Network [OSTI]

Outline Background and Related Work Data Encoding for Failure-Prone Sensor Networks Encoding for Persistent Sensor Networks #12;Outline Background and Related Work Data Encoding for Failure-Prone Sensor Networks Outline 1 Background and Related Work Sensor Networks Failures in Sensor Networks Data Transfer

275

Background: how many people do you know? A model of overdispersion in social networks  

E-Print Network [OSTI]

Overview Background: how many people do you know? A model of overdispersion in social networks for Bayesian Data Analysis #12;Overview Background: how many people do you know? A model of overdispersion their survey data Andrew Gelman Computation for Bayesian Data Analysis #12;Overview Background: how many people

Gelman, Andrew

276

Social and political polarization Background: how many people do you know?  

E-Print Network [OSTI]

Overview Social and political polarization Background: how many people do you know? Learning from surveys #12;Overview Social and political polarization Background: how many people do you know? Learning Social and political polarization Background: how many people do you know? Learning from "How many X's do

Gelman, Andrew

277

Instructions to obtain apostille certification of the FBI background check (Valencia Year-Long Students)  

E-Print Network [OSTI]

Instructions to obtain apostille certification of the FBI background check (Valencia Year-Long Students) Once you have received the FBI background check. You will need to proceed with step two, obtain not waste time submitting your FBI Background Check for certification. 1.) Complete the DS-4194 Request

Hull, Elaine

278

Graphene Nucleation Density on Copper: Fundamental Role of Background Pressure Ivan Vlassiouk,*  

E-Print Network [OSTI]

1 Graphene Nucleation Density on Copper: Fundamental Role of Background Pressure Ivan Vlassiouk the effect of background pressure and synthesis temperature on the graphene crystal sizes in chemical vapor of the background pressure and provide the activation energy for graphene nucleation in atmospheric pressure CVD (9

Feenstra, Randall

279

524 IEEE Transactionson Nuclear Science, Vol. 35, No. 1, February 1988 BACKGROUND EVENTS IN MICROCHANNEL PLATES  

E-Print Network [OSTI]

524 IEEE Transactionson Nuclear Science, Vol. 35, No. 1, February 1988 BACKGROUND EVENTS of the MCP's are found to have no significant effect on the background rate. Detection of 1.46 MeV y rays the environmental or operating conditions must be used to investigate the behavior of the intrinsic MCP background

Wargelin, Bradford J.

280

Radiogenic and Muon-Induced Backgrounds in the LUX Dark Matter Detector  

E-Print Network [OSTI]

The Large Underground Xenon (LUX) dark matter experiment aims to detect rare low-energy interactions from Weakly Interacting Massive Particles (WIMPs). The radiogenic backgrounds in the LUX detector have been measured and compared with Monte Carlo simulation. Measurements of LUX high-energy data have provided direct constraints on all background sources contributing to the background model. The expected background rate from the background model for the 85.3 day WIMP search run is $(2.6\\pm0.2_{\\textrm{stat}}\\pm0.4_{\\textrm{sys}})\\times10^{-3}$~events~keV$_{ee}^{-1}$~kg$^{-1}$~day$^{-1}$ in a 118~kg fiducial volume. The observed background rate is $(3.6\\pm0.4_{\\textrm{stat}})\\times10^{-3}$~events~keV$_{ee}^{-1}$~kg$^{-1}$~day$^{-1}$, consistent with model projections. The expectation for the radiogenic background in a subsequent one-year run is presented.

Akerib, D S; Bai, X; Bailey, A J; Balajthy, J; Bernard, E; Bernstein, A; Bradley, A; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Coffey, T; Currie, A; de Viveiros, L; Dobi, A; Dobson, J; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Flores, C; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C; Hertel, S A; Horn, M; Huang, D Q; Ihm, M; Jacobsen, R G; Kazkaz, K; Knoche, R; Larsen, N A; Lee, C; Lindote, A; Lopes, M I; Malling, D C; Mannino, R; McKinsey, D N; Mei, D -M; Mock, J; Moongweluwan, M; Morad, J; Murphy, A St J; Nehrkorn, C; Nelson, H; Neves, F; Ott, R A; Pangilinan, M; Parker, P D; Pease, E K; Pech, K; Phelps, P; Reichhart, L; Shutt, T; Silva, C; Solovov, V N; Sorensen, P; O'Sullivan, K; Sumner, T J; Szydagis, M; Taylor, D; Tennyson, B; Tiedt, D R; Tripathi, M; Uvarov, S; Verbus, J R; Walsh, N; Webb, R; White, J T; Witherell, M S; Wolfs, F L H; Woods, M; Zhang, C

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Establishment of a Background Environmental Monitoring Station for the PNNL Campus  

SciTech Connect (OSTI)

The environmental surveillance of background levels of radionuclides and, in particular, the siting of a background environmental surveillance (monitoring) station are examined. Many published works identify and stress the need for background monitoring; however, little definitive and comprehensive information for siting a station exists. A definition of an ideal background monitoring location and the generic criteria recommended for use in establishing such a background monitoring location are proposed. There are seven primary (mandatory) criteria described with two additional, optional criteria. The criteria are applied to the Richland, Washington (WA), Pacific Northwest National Laboratory (PNNL) Campus, which currently uses background monitoring data from the nearby Hanford Site. Eleven potential background monitoring sites were identified, with one location in Benton City, WA found to meet all of the mandatory and optional criteria. It is expected that the new sampler will be installed and operating by the end of June, 2015.

Fritz, Brad G.; Snyder, Sandra F.; Barnett, J. M.; Bisping, Lynn E.; Rishel, Jeremy P.

2014-12-18T23:59:59.000Z

282

Possible generation of $?$-ray laser by electrons wiggling in a background laser  

E-Print Network [OSTI]

The possibility of $\\gamma-$ray laser generation by the radiation of wiggling electrons in an usual background laser is discussed.

Qi-Ren Zhang

2014-08-13T23:59:59.000Z

283

E-Print Network 3.0 - acoustic background noise Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

NOISE LEVELS IN STUDIOS AND AUDITORIA A. JAMES Sound Research Laboratories, Saxon House... complex computer and scale modelling. The specification of a background noise...

284

Background T  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

quality, navigation, recreation, cultural resources, fish protection operations and ecosystem function needs, as well as potential effects of climate change. The U.S. Entity and...

285

Legal Background  

Office of Legacy Management (LM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou$0.C. 20545*. . : '*I_ - I _ _ _Text of Decision

286

Legal Background  

Office of Legacy Management (LM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou$0.C. 20545*. . : '*I_ - I _ _ _Text of DecisionLegal

287

Legal Background  

Office of Legacy Management (LM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou$0.C. 20545*. . : '*I_ - I _ _ _Text of

288

Background T  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAboutScience Program CumulusAMarch-6,-2015BSCmemo.pdfDECEMBEREStrategy

289

CAMD Background  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformationCenterResearch HighlightsToolsBESEnergyArchaeologyBylawsSEP 10

290

The Impact of Background Error on Incomplete Observations for 4D-Var Data Assimilation with  

E-Print Network [OSTI]

The Impact of Background Error on Incomplete Observations for 4D-Var Data Assimilation with the FSU on the 4D- Var data assimilation, twin experiments were carried out with the dy- namical core of the new is also investigated. Keywords: Data assimilation, incomplete observations, background error. 1

Navon, Michael

291

Micro-Raman Spectroscopy of Algae: Composition Analysis and Fluorescence Background Behavior  

E-Print Network [OSTI]

ARTICLE Micro-Raman Spectroscopy of Algae: Composition Analysis and Fluorescence Background performed using Stokes Raman scattering for compositional analysis of algae. Two algal species, Chlorella while acquiring Raman signals from the algae. The time dependence of fluorescence background is char

292

HIGH SCHOOL BACKGROUND OF FIRST-TIME STUDENTS UNIVERSITY OF HAWAI`I  

E-Print Network [OSTI]

HIGH SCHOOL BACKGROUND OF FIRST-TIME STUDENTS UNIVERSITY OF HAWAI`I FALL 2007 Institutional, Students Reports available online at: http://www.hawaii.edu/iro/maps.htm #12;HIGH SCHOOL BACKGROUND 1). Enrollment of first-time students from Hawai`i high schools measured 5,967, a 9.4% increase from

293

Fast Illumination-invariant Background Subtraction using Two Views: Error Analysis, Sensor Placement and Applications  

E-Print Network [OSTI]

Fast Illumination-invariant Background Subtraction using Two Views: Error Analysis, Sensor£ Abstract Background modeling and subtraction to detect new or moving objects in a scene is an important a detailed analysis of such errors. Then, we propose a sensor configuration that eliminates false de

Paragios, Nikos

294

Measurement of the background in the NEMO 3 double beta decay experiment  

E-Print Network [OSTI]

In the double beta decay experiment NEMO~3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO~3 to evaluate the backgrounds resulting from most if not all possible origins. It also illustrates the power of the combined tracking-calorimetry technique used in the experiment.

Argyriades, J; Augier, C; Baker, J; Barabash, A S; Bongrand, M; Broudin-Bay, G; Brudanin, V B; Caffrey, A J; Chapon, A; Chauveau, E; Daraktchieva, Z; Durand, D; Egorov, V G; Fatemi-Ghomi, N; Flack, R; Freshville, A; Guillon, B; Hubert, Ph; Jullian, S; Kauer, M; King, S; Kochetov, O I; Konovalov, S I; Kovalenko, V E; Lalanne, D; Lang, K; Lemi`ere, Y; Lutter, G; Mamedov, F; Marquet, Ch; Martn-Albo, J; Mauger, F; Nachab, A; Nasteva, I; Nemchenok, I B; Nova, F; Novella, P; Ohsumi, H; Pahlka, R B; Perrot, F; Piquemal, F; Reyss, J L; Ricol, J S; Saakyan, R; Sarazin, X; Simard, L; Shitov, Yu A; Smolnikov, A A; Snow, S; Sldner-Rembold, S; Stekl, I; Sutton, C S; Szklarz, G; Thomas, J; Timkin, V V; Tretyak, V I; Tretyak, Vl I; Umatov, V I; Vla, L; Vanyushin, I A; Vasiliev, V A; Vorobel, V; Vylov, Ts

2009-01-01T23:59:59.000Z

295

Monte Carlo Calculations of the Intrinsic Detector Backgrounds for the Karlsruhe Tritium Neutrino Experiment  

E-Print Network [OSTI]

Monte Carlo Calculations of the Intrinsic Detector Backgrounds for the Karlsruhe Tritium Neutrino of the Intrinsic Detector Backgrounds for the Karlsruhe Tritium Neutrino Experiment Michelle L. Leber Chair of the Supervisory Committee: Professor John F. Wilkerson Physics The Karlsruhe Tritium Neutrino Experiment (KATRIN

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

296

iU/riA ii riA Background and Technical Information for Collectors  

E-Print Network [OSTI]

m^ m im^Hii iU/riA ii riA Background and Technical Information for Collectors mmBiological Laboial Circular 111 #12;#12;DUCK STAMP DATA Background and Technical Information for Collectors By Edna N. Sater and conservationists, it aroused widespread interest among stamp collectors, many of whom had not previously collected

297

Social and political polarization Background: how many people do you know?  

E-Print Network [OSTI]

Overview Social and political polarization Background: how many people do you know? Learning from;Overview Social and political polarization Background: how many people do you know? Learning from "How many people do you know? Learning from "How many X's do you know" surveys Next Overview Social and political

Gelman, Andrew

298

Using Background Knowledge to Rank Itemsets Nikolaj Tatti and Michael Mampaey  

E-Print Network [OSTI]

for more flexible approaches for infus- ing background knowledge. Namely, we show that we can efficiently that these statistics describe forms of data that occur in practice and have been studied in data mining. To infuse-first search strate- gies [2,21]. The drawback of frequency is that we cannot infuse any background knowledge

299

LArGe - Active background suppression using argon scintillation for the GERDA $0\  

E-Print Network [OSTI]

LArGe is a GERDA low-background test facility to study novel background suppression methods in a low-background environment, for future application in the GERDA experiment. Similar to GERDA, LArGe operates bare germanium detectors submersed into liquid argon (1 m$^3$, 1.4 tons), which in addition is instrumented with photomultipliers to detect argon scintillation light. The scintillation signals are used in anti-coincidence with the germanium detectors to effectively suppress background events that deposit energy in the liquid argon. The background suppression efficiency was studied in combination with a pulse shape discrimination (PSD) technique using a BEGe detector for various sources, which represent characteristic backgrounds to GERDA. Suppression factors of a few times $10^3$ have been achieved. First background data of LArGe with a coaxial HPGe detector (without PSD) yield a background index of (0.12$-$4.6)$\\cdot 10^{-2}$ cts/(keV$\\cdot$kg$\\cdot$y) (90% C.L.), which is at the level of GERDA Phase I. Fu...

Agostini, M; Budj, D; Cattadori, C; Gangapshev, A; Gusev, K; Heisel, M; Junker, M; Klimenko, A; Lubashevskiy, A; Pelczar, K; Schnert, S; Smolnikov, A; Zuzel, G

2015-01-01T23:59:59.000Z

300

Predicted X-ray backgrounds for the International X-ray Observatory  

E-Print Network [OSTI]

The background that will be observed by IXO's X-ray detectors naturally separates into two components: (1) a Cosmic X-ray Background (CXB), primarily due to unresolved point sources at high energies (E>2 keV), along with ...

Bautz, Marshall W.

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Effect of Background Emissivity on Gas Detection in Thermal Hyperspectral Imagery  

SciTech Connect (OSTI)

Detecting and identifying weak gaseous plumes using thermal imaging data is complicated by many factors. These include variability due to atmosphere, ground and plume temper- ature, and background clutter. This paper presents an analysis of one formulation of the physics-based radiance model, which describes at-sensor observed radiance. The background emissivity and plume/ground temperatures are isolated, and their effects on net chemical signal are described. This analysis shows that the plumes physical state, emission or absorption, is directly dependent on the background emissivity. It then describes what conditions on the background emissivity have inhibiting effects on the net chemical signal. These claims are illustrated by analyzing synthetic hyperspectral imaging data with the Adaptive Matched Filter using four chemicals and three distinct background emissivities. Two chemicals (Carbontetrachloride and Tetraflourosilane) in the analysis had a very strong relationship with the background emissivities: they exhibited absorbance over a small range of wavenumbers and the background emissivities showed a consistent ordering at these wavenumbers. Analysis of simulated hyperspectral images containing these chemicals showed complete agreement with the analysis of the physics-based model that described when the background emissivities would have inhibiting effects on gas detection. The other chemicals considered (Ammonia and Tributylphosphate) exhibited very complex absorbance structure across the longwave infrared spectrum. Analysis of images containing these chemicals revealed that the the analysis of the physics-based model did not hold completely for these complex chemicals but did suggest that gas detection was dominated by their dominant absorbance features. These results provide some explanation of the effect of the background emissivity on gas detection and a more general exploration of gas absorbance/background emissivity variability and their effects on gas detection is warranted. i

Walsh, Stephen J.; Tardiff, Mark F.; Chilton, Lawrence K.; Metoyer, Candace N.

2008-10-02T23:59:59.000Z

302

Next-Generation Germanium Spectrometer Background Reduction Techniques at 2 MeV  

SciTech Connect (OSTI)

The Majorana project, a next-generation 76Ge neutrinoless double-beta decay experiment being undertaken by a large international collaboration, has the goal of measuring the neutrinoless double-beta decay rate by observing monochromatic events at 2039 keV in 500 kg of isotopically enriched 76Ge gamma-ray spectrometers. In order to achieve the desired sensitivity limit, the background in the 2037-2041 keV region must be reduced to <1 event per year in the entire germanium array. The effects of various background reduction techniques, and the combination thereof, to produce a huge 76Ge spectrometer array with virtually zero background are discussed.

Brodzinski, Ronald L.

2005-04-01T23:59:59.000Z

303

The Relationship of Rhythmic and Melodic Perception with Background Music Distraction in College Level Students  

E-Print Network [OSTI]

This study investigated relationships among the ability to audiate musical stimuli, background music condition, familiarity, gender, general academic achievement, age, and frequency of use on the level of distraction caused ...

Dove, Michael Karl

2009-04-27T23:59:59.000Z

304

2.8 Carbon Nanotubes (Fullerenes) 2.8.1 Background  

E-Print Network [OSTI]

85 2.8 Carbon Nanotubes (Fullerenes) 2.8.1 Background After long being available only in research or apparently under consideration, though the concept has been discussed. Carbon nanotubes and fullerenes

305

Background-subtraction using contour-based fusion of thermal and visible imagery  

E-Print Network [OSTI]

rights reserved. Keywords: Background-subtraction; Fusion; Thermal imagery; Infrared; FLIR; Contour of the electromagnetic spectrum, long-wave infrared (thermal) and visible light. Thermal (FLIR) and color video cameras

Davis, James W.

306

Kernel Level Energy-Efficient 3G Background Traffic Shaper for Android Smartphones  

E-Print Network [OSTI]

Kernel Level Energy-Efficient 3G Background Traffic Shaper for Android Smartphones Ekhiotz Jon energy-efficient, the lack of energy aware- ness on the software front is becoming all too apparent

307

An upper bound from helioseismology on the stochastic background of gravitational waves  

E-Print Network [OSTI]

The universe is expected to be permeated by a stochastic background of gravitational radiation of astrophysical and cosmological origin. This background is capable of exciting oscillations in solar-like stars. Here we show that solar-like oscillators can be employed as giant hydrodynamical detectors for such a background in the muHz to mHz frequency range, which has remained essentially unexplored until today. We demonstrate this approach by using high-precision radial velocity data for the Sun to constrain the normalized energy density of the stochastic gravitational-wave background around 0.11 mHz. These results open up the possibility for asteroseismic missions like CoRoT and Kepler to probe fundamental physics.

Daniel M. Siegel; Markus Roth

2014-03-28T23:59:59.000Z

308

E-Print Network 3.0 - atmospheric neutrinos background Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Experiment will perform an essentially background... -free measurement of neutrinoless double-beta decay (0) in 120 kg of 76 Ge with the goal of determining the neutrino... mass....

309

Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity  

SciTech Connect (OSTI)

Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash.

Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

2007-02-07T23:59:59.000Z

310

Simulation of Radiation Backgrounds associated with the HEXRI Diagnostics at the National Ignition Facility  

SciTech Connect (OSTI)

Experiments resulting in a significant neutron yield are scheduled to start in 2010 at the National Ignition Facility (NIF). A wide range of diagnostics will be used to measure several parameters of implosion such as the core and fuel shape, temperatures and densities, and neutron yield. Accurate evaluations of the neutron and gamma backgrounds are important for several diagnostics, such as the High Energy X-ray Imager (HEXRI). Several Monte-Carlo simulations were performed to identify the expected signal to background ratios at several potential locations for the HEXRI diagnostics. Gamma backgrounds were significantly reduced by using tungsten collimators. The collimators resulted in the reduction of the gamma background at the HEXRI scintillators by more than an order of magnitude during the first 40 ns following a THD shot.

Khater, H; Dauffy, L; Tommasini, R; Eckart, M; Eder, D

2009-10-05T23:59:59.000Z

311

SPECTROPHOTOMETRIC DETERMINATION OF Fe IN DRINKING WATER Background Reading: Harris, 7th  

E-Print Network [OSTI]

SPECTROPHOTOMETRIC DETERMINATION OF Fe IN DRINKING WATER Background Reading: Harris, 7th ed., Chap contaminants in drinking water can be determined spectrophotometrically, including iron. Although iron the iron content of drinking water to

Weston, Ken

312

SIMULATION OF RADIATION BACKGROUNDS ASSOCIATED WITH NUCLEAR DIAGNOSTICS IN THE NATIONAL IGNITION FACILITY  

SciTech Connect (OSTI)

Experiments resulting in a significant neutron yield are scheduled to start in 2010 at the National Ignition Facility (NIF). Several experiments utilizing Tritium-Hydrogen-Deuterium (THD) and Deuterium-Tritium (DT) targets are scheduled as part of the National Ignition Campaign (NIC). A wide range of diagnostics will be used to measure several parameters of implosion such as the core and fuel shape, temperatures and densities, and neutron yield. Accurate evaluations of the neutron and gamma backgrounds are important for several diagnostics, such as the High Energy X-ray Imager (HEXRI) and Neutron-Time-Of-Flight (nTOF). Several sources of neutron and gamma backgrounds will impact the accuracy of the diagnostics measurements. Fusion neutrons generated by fuel burn and secondary neutrons resulting from the fusion neutrons interaction with structures present inside and outside the Target Chamber (TC) contribute to the neutron background. In the meantime, X-rays emitted from the implosion, X-rays resulting from Laser Plasma Interaction (LPI) of NIF beams with the hohlraum, and gamma-rays induced by neutron interactions with different structures inside and outside the TC contribute to the gamma background. A detailed model has been developed of the NIF facility and all structures inside the TC. Several Monte-Carlo simulations were performed to identify the expected signal-to- background ratios at several potential locations for the HEXRI and nTOF diagnostics. Gamma backgrounds associated with HEXRI were significantly reduced by using a tungsten collimator. The collimator resulted in the reduction of the gamma background at the HEXRI scintillator by more than an order of magnitude during the first 40 ns following a THD shot. The nTOF20 detectors inside the Neutron Spectrometry room are exposed to low levels of neutron and gamma background during yield shots.

Khater, H; Dauffy, L; Tommasini, R; Eckart, M; Eder, D

2009-08-19T23:59:59.000Z

313

Access to health care for individuals with developmental disabilities from minority backgrounds  

E-Print Network [OSTI]

MENTAL RETARDATION VOLUME 42, NUMBER 6: 459470 DECEMBER 2004 459qAmerican Association on Mental Retardation Access to Health Care for Individuals With Developmental Disabilities From Minority Backgrounds Amanda Reichard, Therese Marie Sacco, and H.... Rutherford Turnbull, III Abstract In this project we examined access to health care by individuals with developmental disabilities in Kansas from low-income populations and from minority backgrounds. Four criteria for deter- mining access were employed...

Reichard, Amanda; Sacco, T. M.; Turnbull, H. Rutherford

2011-12-27T23:59:59.000Z

314

Solar neutrino-electron scattering as background limitation for double beta decay  

E-Print Network [OSTI]

The background on double beta decay searches due to elastic electron scattering of solar neutrinos of all double beta emitters with Q-value larger than 2 MeV is calculated, taking into account survival probability and flux uncertainties of solar neutrinos. This work determines the background level to be [1-2]E-7 counts /keV/kg/yr, depending on the precise Q-value of the double beta emitter. It is also shown that the background level increases dramatically if going to lower Q-values. Furthermore, studies are done for various detector systems under consideration for next generation experiments. It was found that experiments based on loaded liquid scintillator have to expect a higher background. Within the given nuclear matrix element uncertainties any approach exploring the normal hierarchy has to face this irreducible background, which is a limitation on the minimal achievable background for purely calorimetric approaches. Large scale liquid scintillator experiments might encounter this problem already while exploring the inverted hierarchy. Potential caveats by using more sophisticated experimental setups are also discussed.

N. F. de Barros; K. Zuber

2011-09-16T23:59:59.000Z

315

Sub-mm and X-ray background: two unrelated phenomena?  

E-Print Network [OSTI]

Obscured AGNs are thought to contribute a large fraction of the hard X-ray background (2-10 keV), and have also been proposed as the powerhouse of a fraction of the SCUBA sources which make most of the background at 850um, thus providing a link between the two spectral windows. We have tackled this issue by comparing data at 2-10 keV and at 850um for a sample of 34 sources at fluxes (or limiting fluxes) which resolve most of the background in the two bands. We present here new SCUBA observations, and new correlations between separate data sets retrieved from the literature. Similar correlations presented by others are added for completeness. None of the 11 hard X-ray (2-10 keV) sources has a counterpart at 850um, with the exception of a Chandra source in the SSA13 field, which is a candidate type 2, heavily absorbed QSO at high redshift. The ratios F(850um)/F(5keV) (mostly upper limits) of the X-ray sources are significantly lower than the value observed for the cosmic background. In particular, we obtain that 2-10 keV sources brighter than 10^-15 erg s^-1 cm^-2, which make at least 75% of the background in this band, contribute for less than 7% to the submillimeter background. Out of the 24 SCUBA sources, 23 are undetected by Chandra. The ratios F(850um)/F(5keV) (mostly lower limits) of these SCUBA sources indicate that most of them must be powered either by starburst activity, or by an AGN which is obscured by a column Nh > 10^25 cm^-2, with a reflection efficiency in the hard X rays significantly lower than 1% in most cases. However, AGNs of this type could not contribute significantly to the 2-10 keV background.

P. Severgnini; R. Maiolino; M. Salvati; D. Axon; A. Cimatti; F. Fiore; R. Gilli; F. La Franca; A. Marconi; G. Matt; G. Risaliti; C. Vignali

2000-06-16T23:59:59.000Z

316

Measurement of Neutron Background at the Pyhasalmi mine for CUPP Project, Finland  

E-Print Network [OSTI]

A natural neutron flux is one of significant kind of background in high-sensitive underground experiments. Therefore, when scheduling a delicate underground measurements one needs to measure neutron background. Deep underground the most significant source of neutrons are the U-Th natural radioactive chains giving a fission spectrum with the temperature of 2-3 MeV. Another source is the U-Th alpha-reactions on light nuclei of mine rock giving neutrons with different spectra in the 1-15 MeV energy region. Normal basalt mine rocks contain 1 ppm g/g of U-238 and less. Deep underground those rocks produce natural neutron fluxes of 10^{-7} - 10^{-6} cm^{-2}s^{-1} above 1 MeV. To measure such a background one needs a special techniques. In the Institute for Nuclear Research, Moscow, the neutron spectrometer was developed and built which is sensitive to such a low neutron fluxes. At the end of 2001 the collection of neutron data at the Pyhasalmi mine was started for the CUPP project. During 2002 the background and rough energy spectra of neutron at underground levels 410, 660, 990 and 1410 m were measured. The result of the measurement of the neutron background at different levels of the Pyhasalmi mine is presented and discussed. Data analysis is performed in different energy ranges from thermal neutrons up to 25 MeV and above.

J. N. Abdurashitov; V. N. Gavrin; V. L. Matushko; A. A. Shikhin; V. E. Yants; J. Peltoniemi; T. Keranen

2006-07-20T23:59:59.000Z

317

Spallation Backgrounds in Super-Kamiokande Are Made in Muon-Induced Showers  

E-Print Network [OSTI]

Crucial questions about solar and supernova neutrinos remain unanswered. Super-Kamiokande has the exposure needed for progress, but detector backgrounds are a limiting factor. A leading component is the beta decays of isotopes produced by cosmic-ray muons and their secondaries, which initiate nuclear spallation reactions. Cuts of events after and surrounding muon tracks reduce this spallation decay background by $\\simeq 90\\%$ (at a cost of $\\simeq 20\\%$ deadtime), but its rate at 6 -- 18 MeV is still dominant. A better way to cut this background was suggested in a Super-Kamiokande paper [Bays {\\it et al.}, Phys.~Rev.~D {\\bf 85}, 052007 (2012)] on a search for the diffuse supernova neutrino background. They found that spallation decays above 16 MeV were preceded near the same location by a peak in the apparent Cherenkov light profile from the muon; a more aggressive cut was applied to a limited section of the muon track, leading to decreased background without increased deadtime. We put their empirical discove...

Li, Shirley Weishi

2015-01-01T23:59:59.000Z

318

Refined Topological Vertex and Duality of Gauge Theories in Generic Omega Backgrounds  

E-Print Network [OSTI]

The partition functions of refined topological strings(A-models) are computed, which give rise to the circle-compactified five-dimensional supersymmetric linear quiver gauge theories in generic (not necessarily self-dual) Omega backgrounds. Based on the slicing independence conjecture of refined topological string partition functions, it is demonstrated explicitly that the duality exists between $SU(N)^{M-1}$ and $SU(M)^{N-1}$ supersymmetric linear quiver gauge theories, even in generic Omega backgrounds. It is found that the relations between string moduli and gauge moduli are deformed from the self-dual case. However if the duality map which preserves the ratio of the Omega background parameters q and t, is considered, duality maps of the gauge moduli are not changed from the self-dual case.

Kei Ito

2012-11-29T23:59:59.000Z

319

Invited Article: Characterization of background sources in space-based time-of-flight mass spectrometers  

SciTech Connect (OSTI)

For instruments that use time-of-flight techniques to measure space plasma, there are common sources of background signals that evidence themselves in the data. The background from these sources may increase the complexity of data analysis and reduce the signal-to-noise response of the instrument, thereby diminishing the science value or usefulness of the data. This paper reviews several sources of background commonly found in time-of-flight mass spectrometers and illustrates their effect in actual data using examples from ACE-SWICS and MESSENGER-FIPS. Sources include penetrating particles and radiation, UV photons, energy straggling and angular scattering, electron stimulated desorption of ions, ion-induced electron emission, accidental coincidence events, and noise signatures from instrument electronics. Data signatures of these sources are shown, as well as mitigation strategies and design considerations for future instruments.

Gilbert, J. A.; Gershman, D. J.; Gloeckler, G.; Lundgren, R. A.; Zurbuchen, T. H. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward St, Ann Arbor, Michigan 48109 (United States); Orlando, T. M.; McLain, J. [Georgia Institute of Technology, 225 North Ave NW, Atlanta, Georgia 30332 (United States); Steiger, R. von [International Space Science Institute, Hallerstrasse 6, CH-3012 Bern, Switzerland and Physikalisches Institut, Universitt Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

2014-09-15T23:59:59.000Z

320

Design of a novel Cherenkov detectors system for machine induced background monitoring in the CMS cavern  

E-Print Network [OSTI]

A novel detector system has been designed for an efficient online measurement of the machineinduced background in the CMS experimental cavern. The suppression of the CMS cavern background originating from pp collision products and the 25 ns bunch spacing have set the requirements for the detector design. Each detector unit will be a radiation hard, cylindrical Cherenkov radiator optically coupled to an ultra-fast UV-sensitive photomultiplier tube, providing a prompt, directionally sensitive measurement. Simulation and test beam measurements have shown the achievability of the goals that have driven the baseline design. The system will consist of 20 azimuthally distributed detectors per end, installed at a radius of r ~ 180 cm and a distance 20.6 m away from the CMS interaction region. The detector units will enable a measurement of the transverse distribution of the bunchby- bunch machine induced background flux. This will provide important feedback from the CMS on the beam conditions during the LHC machine s...

Orfanelli, Styliani; Giunta, Marina; Stickland, David P; Ambrose, Mitchell J; Rusack, Roger; Finkel, Alexey

2013-01-01T23:59:59.000Z

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321

High redshift AGNs and HI reionisation: limits from the unresolved X-ray background  

E-Print Network [OSTI]

The rapidly declining population of bright quasars at z~3 appears to make an increasingly small contribution to the ionising background at the HI Lyman limit. It is then generally though that massive stars in (pre-)galactic systems may provide the additional ionising flux needed to complete HI reionisation by z>6. A galaxy dominated background, however, may require that the escape fraction of Lyman continuum radiation from high redshift galaxies is as high as 10%, a value somewhat at odds with (admittedly scarce) observational constraints. High escape fractions from dwarf galaxies have been advocated, or, alternatively, a so-far undetected (or barely detected) population of unobscured, high-redshift faint AGNs. Here we question the latter hypothesis, and show that such sources, to be consistent with the measured level of the unresolved X-ray background at z=0, can provide a fraction of the HII filling factor not larger than 13% by z=6. The fraction rises to 10%.

Haardt, Francesco

2015-01-01T23:59:59.000Z

322

Influence of suprathermal background electrons on strong auroral double layers: Observations  

SciTech Connect (OSTI)

This study examines the properties and evolution of strong, laminar double layers in the downward current region of the aurora and present several previously unpublished events from the Fast Auroral SnapshoT (FAST) satellite. Analysis of an event is presented for which the FAST satellite appears to have dwelled on the high-potential side (high-altitude side) of a double layer for an extended period, suggesting that a small (few percent of density) background of suprathermal electrons can strongly influence the structure and stability of double layers. From these observations, it is inferred that the accelerated electrons can be accelerated by either of two classes of double layers: (1) self-regulated double layers (varying field-aligned potential, with weak or no suprathermal electron background) or (2) externally regulated double layers (less variable field-aligned potential, with significant suprathermal electron background). Elements of the interpretation presented here are supported by numerical simulations, as reported in two accompanying papers.

Andersson, L. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80309 (United States); Newman, D. L.; Goldman, M. V. [Center for Integrated Plasma Studies, University of Colorado, Boulder, Colorado 80309 (United States); Ergun, R. E. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80309 (United States); Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, Colorado (United States); Carlson, C. W.; McFadden, J. P. [Space Science Laboratory, University of California, Berkeley, California 94729 (United States)

2008-07-15T23:59:59.000Z

323

Radon backgrounds in the DRIFT-II directional dark matter experiments  

E-Print Network [OSTI]

Low pressure gas Time Projection Chambers being developed for directional Dark Matter searches offer a technology with high particle identification power, combined with poten- tial to produce a definitive detection of galactic Weakly Interacting Massive Particle (WIMP) Dark Matter. A source of background events in such experiments, able to mimic genuine WIMP in- duced nuclear recoil tracks, arises from potential radon contamination and the recoils that result from associated daughter nuclei, termed Radon Progeny Recoils (RPRs). We present here experi- mental data from a long-term study of this background using the DRIFT-II directional dark matter experiment at the Boulby Underground Laboratory. By detailed examination of event classes in both spatial and time coordinates using 5.5 years of data we show ability to determine the origin of 4 specific background populations and describe development of new technology and mitigation strategies to suppress them.

Daw, E; Gauvreau, J -L; Gold, M; Harmon, L J; Landers, J M; Lee, E R; Loomba, D; Miller, E H; Murphy, A StJ; Paling, S M; Pipe, M; Robinson, M; Sadler, S; Scarff, A; Snowden-Ifft, D P; Spooner, N J C; Walker, D

2013-01-01T23:59:59.000Z

324

Near beam-gas background for LHCb at 3.5 TeV  

E-Print Network [OSTI]

We consider the machine induced backgrounds for LHCb arising from collisions of the beam with residual gas in the long straight sections of the LHC close to the experiment. We concentrate on the background particle fluxes initiated by inelastic beam-gas interactions with a direct line of sight to the experiment, with the potential impact on the experiment increasing for larger beam currents and changing gas pressures. In this paper we calculate the background rates for parameters foreseen with LHC running in 2011, using realistic residual pressure profiles. We also discuss the effect of using a pressure profile formulated in terms of equivalent hydrogen, through weighting of other residual gases by their cross section, upon the radial fluxes from the machine and the detector response. We present the expected rates and the error introduced through this approximation.

Brett, D R; Corti, G; Alessio, F; Jacobsson, R; Talanov, V; Lieng, M H

2011-01-01T23:59:59.000Z

325

Background studies for NaI(Tl) detectors in the ANAIS dark matter project  

SciTech Connect (OSTI)

Several large NaI(Tl) detectors, produced by different companies, have been operated in the Canfranc Underground Laboratory (LSC) in the frame of the ANAIS (Annual modulation with NaI Scintillators) project devoted to the direct detection of dark matter. A complete background model has been developed for a 9.6 kg detector (referred as ANAIS-0 prototype) after a long data taking at LSC. Activities from the natural chains of {sup 238}U and {sup 232}Th, and {sup 40}K in the NaI(Tl) crystal were evaluated applying different methods: discrimination of alpha particles vs beta/gamma background by Pulse Shape Analysis for quantifying the content of the natural chains and coincidence techniques for {sup 40}K. Radioactive contaminations in the detector and shielding components were also determined by HPGe spectrometry. Monte Carlo simulations using Geant4 package were carried out to evaluate their contribution. At high energies, most of the measured background is nicely reproduced; at low energy some non-explained components are still present, although some plausible background sources have been analyzed. The {sup 40}K content of the NaI(Tl) crystal has been confirmed to be the dominant contributor to the measured background with this detector. In addition, preliminary results of the background characterization, presently underway at the LSC, of two recently produced NaI(Tl) detectors, with 12.5 kg mass each, will be presented: cosmogenic induced activity has been clearly observed and is being quantified, and {sup 40}K activity at a level ten times lower than in ANAIS-0 has been determined.

Amar, J.; Borjabad, S.; Cebrin, S.; Cuesta, C.; Fortuo, D.; Garca, E.; Ginestra, C.; Gmez, H.; Martnez, M.; Olivn, M. A.; Ortigoza, Y.; Solrzano, A. Ortiz de; Pobes, C.; Puimedn, J.; Sarsa, M. L.; Villar, J. A.; Villar, P. [Laboratorio de Fsica Nuclear y Astropartculas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza, Spain and Laboratorio Subterrneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estacin, Huesca (Spain)] [Laboratorio de Fsica Nuclear y Astropartculas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza, Spain and Laboratorio Subterrneo de Canfranc, Paseo de los Ayerbe s/n, 22880 Canfranc Estacin, Huesca (Spain)

2013-08-08T23:59:59.000Z

326

THE NEAR-INFRARED BACKGROUND INTENSITY AND ANISOTROPIES DURING THE EPOCH OF REIONIZATION  

SciTech Connect (OSTI)

A fraction of the extragalactic near-infrared (near-IR) background light involves redshifted photons from the ultraviolet (UV) emission from galaxies present during reionization at redshifts above 6. The absolute intensity and the anisotropies of the near-IR background provide an observational probe of the first-light galaxies and their spatial distribution. We estimate the extragalactic background light intensity during reionization by accounting for the stellar and nebular emission from first-light galaxies. We require the UV photon density from these galaxies to generate a reionization history that is consistent with the optical depth to electron scattering from cosmic microwave background measurements. We also require the bright-end luminosity function (LF) of galaxies in our models to reproduce the measured Lyman-dropout LFs at redshifts of 6-8. The absolute intensity is about 0.1-0.4 nW m{sup -2} sr{sup -1} at the peak of its spectrum at {approx}1.1 {mu}m. We also discuss the anisotropy power spectrum of the near-IR background using a halo model to describe the galaxy distribution. We compare our predictions for the anisotropy power spectrum to existing measurements from deep near-IR imaging data from Spitzer/IRAC, Hubble/NICMOS, and AKARI. The predicted rms fluctuations at tens of arcminute angular scales are roughly an order of magnitude smaller than the existing measurements. While strong arguments have been made that the measured fluctuations do not have an origin involving faint low-redshift galaxies, we find that measurements in the literature are also incompatible with galaxies present during the era of reionization. The measured near-IR background anisotropies remain unexplained with an unknown origin.

Cooray, Asantha; Gong Yan; Smidt, Joseph [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Santos, Mario G. [CENTRA, Instituto Superior Tecnico, Technical University of Lisbon, Lisboa 1049-001 (Portugal)

2012-09-01T23:59:59.000Z

327

Construction of a Shallow Underground Low-background Detector for a CTBT Radionuclide Laboratory  

SciTech Connect (OSTI)

The International Monitoring System (IMS) is a verification component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), and in addition to a series of radionuclide monitoring stations, contains sixteen radionuclide laboratories capable of verification of radionuclide station measurements. This paper presents an overview of a new commercially obtained low-background detector system for radionuclide aerosol measurements recently installed in a shallow (>30 meters water equivalent) underground clean-room facility at Pacific Northwest National Laboratory. Specifics such as low-background shielding materials, active shielding methods, and improvements in sensitivity to IMS isotopes will be covered.

Forrester, Joel B.; Greenwood, Lawrence R.; Miley, Harry S.; Myers, Allan W.; Overman, Cory T.

2013-05-01T23:59:59.000Z

328

The impact of non-Planckian effects on radio cosmological backgrounds  

E-Print Network [OSTI]

Non-Planckian (NP) spectral modifications of the CMB radiation spectrum can be produced due to the existence of a non-zero value of the plasma frequency at the recombination epoch. We present here an analysis of NP effects on the radio cosmological background and we derive, for the first time, predictions of their amplitude on three different observables: the CMB spectrum, the Sunyaev-Zel'dovich (SZ) effect in cosmic structures, and the 21-cm background temperature brightness change. We find that NP effect can manifest in the CMB spectrum at $\

Colafrancesco, Sergio; Marchegiani, Paolo

2015-01-01T23:59:59.000Z

329

Low Background Gamma-Ray Spectrometry in the 'Laboratoire Souterrain de Modane'  

SciTech Connect (OSTI)

Most of the underground experiments in physics and many studies in geology, biology or environmental sciences face a common requirement with the necessity of using experimental devices with ultra-low background radioactivity. Many developments involving many different techniques have been used in order to be able to measure extremely low levels of radioactivity in materials. This report will focus on low background gamma-ray spectrometry and will describe the work which has been carried out over the last fifteen years in the 'Laboratoire Souterrain de Modane' (LSM)

Hubert, Ph.; Hubert, F. [Centre d'Etudes Nucleaires de Bordeaux Gradignan, BP 120, Le Haut Vigneau, 33175 Gradignan Cedex (France)

2007-03-28T23:59:59.000Z

330

Numerical modeling of plasma plume evolution against ambient background gas in laser blow off experiments  

SciTech Connect (OSTI)

Two dimensional numerical modelling based on simplified hydrodynamic evolution for an expanding plasma plume (created by laser blow off) against an ambient background gas has been carried out. A comparison with experimental observations shows that these simulations capture most features of the plasma plume expansion. The plume location and other gross features are reproduced as per the experimental observation in quantitative detail. The plume shape evolution and its dependence on the ambient background gas are in good qualitative agreement with the experiment. This suggests that a simplified hydrodynamic expansion model is adequate for the description of plasma plume expansion.

Patel, Bhavesh G.; Das, Amita; Kaw, Predhiman; Singh, Rajesh; Kumar, Ajai [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2012-07-15T23:59:59.000Z

331

The MAJORANA experiment: an ultra-low background search for neutrinoless double-beta decay  

SciTech Connect (OSTI)

The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana Experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to validate whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak.

Phillips, D.; Aguayo Navarrete, Estanislao; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Busch, Matthew; Chan, Yuen-Dat; Christofferson, Cabot-Ann; Collar, J. I.; Combs, Dustin C.; Cooper, R. J.; Detwiler, Jason A.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Esterline, James H.; Fast, James E.; Fields, N.; Finnerty, P.; Fraenkle, Florian; Gehman, Victor; Giovanetti, G. K.; Green, Matthew P.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Horton, Mark; Howard, Stanley; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keller, C.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; LaFerriere, Brian D.; LaRoque, B. H.; Leon, Jonathan D.; Leviner, L.; Loach, J. C.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Merriman, Jason H.; Miller, M. L.; Mizouni, Leila; Nomachi, Masaharu; Orrell, John L.; Overman, Nicole R.; Poon, Alan; Perumpilly, Gopakumar; Prior, Gersende; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Ronquest, M. C.; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Snavely, Kyle J.; Steele, David; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Vorren, Kris R.; Wilkerson, J. F.; Wolfe, B. A.; Yakushev, E.; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.

2012-12-01T23:59:59.000Z

332

Stabilization of the filamentation instability and the anisotropy of the background plasma  

SciTech Connect (OSTI)

The interaction of a relativistic electron beam with an anisotropic Maxwellian plasma is investigated, with a focus on the stabilization condition for the filamentation instability. It is found that this condition is very sensitive to the anisotropy degree of the background plasma so that the investigation of the beam instability may not be easily decoupled from the state of the background plasma in typical fusion conditions. Furthermore, regardless of the plasma isotropy, filamentation can no longer be suppressed when the beam density exceeds a threshold value that is determined.

Bret, A.; Deutsch, C. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Laboratoire de Physique des Gaz et des Plasmas (CNRS-UMR 8578), Universite Paris XI, Batiment 210, 91405 Orsay cedex (France)

2006-02-15T23:59:59.000Z

333

Impact of background flow on dissolution trapping of carbon dioxide injected into saline aquifers  

E-Print Network [OSTI]

While there has been a large interest in studying the role of dissolution-driven free convection in the context of geological sequestration, the contribution of forced convection has been largely ignored. This manuscript considers CO$_2$ sequestration in saline aquifers with natural background flow and uses theoretical arguments to compute the critical background velocity needed to establish the forced convective regime. The theoretical arguments are supported by two dimensional high-resolution numerical simulations which demonstrate the importance of forced convection in enhancing dissolution in aquifers characterised by low Rayleigh numbers.

Rapaka, Saikiran

2011-01-01T23:59:59.000Z

334

(n,n?[gamma]) reactions in 6?3?,?6?5?Cu and background in 0[nu] [beta] [beta] experiments  

E-Print Network [OSTI]

Measurements of (n, xn?[gamma]) reactions in Cu are important for understanding neutroninduced background for certain underground double beta decay experiments. Neutroninduced gammas are a contribution to background for ...

Perepelitsa, Dennis V

2008-01-01T23:59:59.000Z

335

Improved Upper Limits on the Stochastic Gravitational-Wave Background from 20092010 LIGO and Virgo Data  

E-Print Network [OSTI]

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is ...

Aasi, J.

336

Upper limits on a stochastic gravitational-wave background using LIGO and Virgo interferometers at 6001000 Hz  

E-Print Network [OSTI]

A stochastic background of gravitational waves is expected to arise from a superposition of many incoherent sources of gravitational waves, of either cosmological or astrophysical origin. This background is a target for ...

Barsotti, Lisa

337

Characterisation and mitigation of beam-induced backgrounds observed in the ATLAS detector during the 2011 proton-proton run  

E-Print Network [OSTI]

This paper presents a summary of beam-induced backgrounds observed in the ATLAS detector and discusses methods to tag and remove background contaminated events in data. Trigger-rate based monitoring of beam-related backgrounds is presented. The correlations of backgrounds with machine conditions, such as residual pressure in the beam-pipe, are discussed. Results from dedicated beam-background simulations are shown, and their qualitative agreement with data is evaluated. Data taken during the passage of unpaired, i.e. non-colliding, proton bunches is used to obtain background-enriched data samples. These are used to identify characteristic features of beam-induced backgrounds, which then are exploited to develop dedicated background tagging tools. These tools, based on observables in the Pixel detector, the muon spectrometer and the calorimeters, are described in detail and their efficiencies are evaluated. Finally an example of an application of these techniques to a monojet analysis is given, which demonstra...

Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; kesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Andrieux, Marie-Laure; Anduaga, Xabier; Angelidakis, Stylianos; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Ask, Stefan; sman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Atkinson, Markus; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Backus Mayes, John; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Balek, Petr; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimares da Costa, Joo; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Basye, Austin; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Begel, Michael; Behar Harpaz, Silvia; Behera, Prafulla; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jrg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien

2013-01-01T23:59:59.000Z

338

Josh is a pragmatic guy. He knows that a strong background in geology and environmental  

E-Print Network [OSTI]

Josh is a pragmatic guy. He knows that a strong background in geology and environmental geosciences will help him excel in the energy sector. So, as a freshman, he took the intro to geology course. "My fit. "As a geology major, I have to get out in the field to really apply what I've learned in class

Kasman, Alex

339

Neutrino condensates at center of galaxies as background for the MSW mechanism  

E-Print Network [OSTI]

The possibility is explored that neutrino condensates, possible candidates for the explanation of very massive objects in galactic centers, could act as background for the Mikheyev-Smirnov-Wolfeinstein mechanism responsible of neutrino oscillations. Assuming a simple neutrino star model with constant density, the lower limit of the mass squared difference of neutrino oscillations is inferred. Consequences on neutrino asymmetry are discussed.

S. Capozziello; G. Iovane; G. Lambiase

2003-04-01T23:59:59.000Z

340

Controlling Low-Rate Signal Path Microdischarge for an Ultra-Low-Background Proportional Counter  

SciTech Connect (OSTI)

ABSTRACT Pacific Northwest National Laboratory (PNNL) has developed an ultra-low-background proportional counter (ULBPC) made of high purity copper. These detectors are part of an ultra-low-background counting system (ULBCS) in the newly constructed shallow underground laboratory at PNNL (at a depth of ~30 meters water-equivalent). To control backgrounds, the current preamplifier electronics are located outside the ULBCS shielding. Thus the signal from the detector travels through ~1 meter of cable and is potentially susceptible to high voltage microdischarge and other sources of electronic noise. Based on initial successful tests, commercial cables and connectors were used for this critical signal path. Subsequent testing across different batches of commercial cables and connectors, however, showed unwanted (but still low) rates of microdischarge noise. To control this noise source, two approaches were pursued: first, to carefully validate cables, connectors, and other commercial components in this critical signal path, making modifications where necessary; second, to develop a custom low-noise, low-background preamplifier that can be integrated with the ULBPC and thus remove most commercial components from the critical signal path. This integrated preamplifier approach is based on the Amptek A250 low-noise charge-integrating preamplifier module. The initial microdischarge signals observed are presented and characterized according to the suspected source. Each of the approaches for mitigation is described, and the results from both are compared with each other and with the original performance seen with commercial cables and connectors.

Mace, Emily K.; Aalseth, Craig E.; Bonicalzi, Ricco; Day, Anthony R.; Hoppe, Eric W.; Keillor, Martin E.; Myers, Allan W.; Overman, Cory T.; Seifert, Allen

2013-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Project plan for the background soils project for the Paducah Gaseous Diffusion Plant, Paducah, Kentucky  

SciTech Connect (OSTI)

The Background Soils Project for the Paducah Gaseous Diffusion Plant (BSPP) will determine the background concentration levels of selected naturally occurring metals, other inorganics, and radionuclides in soils from uncontaminated areas in proximity to the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky. The data will be used for comparison with characterization and compliance data for soils, with significant differences being indicative of contamination. All data collected as part of this project will be in addition to other background databases established for the PGDP. The BSPP will address the variability of surface and near-surface concentration levels with respect to (1) soil taxonomical types (series) and (2) soil sampling depths within a specific soil profile. The BSPP will also address the variability of concentration levels in deeper geologic formations by collecting samples of geologic materials. The BSPP will establish a database, with recommendations on how to use the data for contaminated site assessment, and provide data to estimate the potential human and health and ecological risk associated with background level concentrations of potentially hazardous constituents. BSPP data will be used or applied as follows.

NONE

1995-09-01T23:59:59.000Z

342

Heavy Higgs signal-background interference in gg --> VV in the Standard Model plus real singlet  

E-Print Network [OSTI]

For the Standard Model extended with a real scalar singlet field, the modification of the heavy Higgs signal due to interference with the continuum background and the off-shell light Higgs contribution is studied for gg --> ZZ, WW --> 4 lepton processes at the Large Hadron Collider. A public program that allows to simulate the full interference is presented.

Kauer, Nikolas

2015-01-01T23:59:59.000Z

343

Sub-mm and X-ray background two unrelated phenomena?  

E-Print Network [OSTI]

Obscured AGNs are thought to contribute a large fraction of the hard X-ray background (2-10 keV), and have also been proposed as the powerhouse of a fraction of the SCUBA sources which make most of the background at 850um, thus providing a link between the two spectral windows. We have tackled this issue by comparing data at 2-10 keV and at 850um for a sample of 34 sources at fluxes (or limiting fluxes) which resolve most of the background in the two bands. We present here new SCUBA observations, and new correlations between separate data sets retrieved from the literature. Similar correlations presented by others are added for completeness. None of the 11 hard X-ray (2-10 keV) sources has a counterpart at 850um, with the exception of a Chandra source in the SSA13 field, which is a candidate type 2, heavily absorbed QSO at high redshift. The ratios F(850um)/F(5keV) (mostly upper limits) of the X-ray sources are significantly lower than the value observed for the cosmic background. In particular, we obtain tha...

Severgnini, P; Salvati, M; Axon, D J; Cimatti, A; Fiore, F; Gilli, R; La Franca, F; Marconi, A; Matt, G; Risaliti, G; Vignali, C

2000-01-01T23:59:59.000Z

344

Dynamics of Scalar Fields in the Background of Rotating Black Holes  

E-Print Network [OSTI]

A numerical study of the evolution of a massless scalar field in the background of rotating black holes is presented. First, solutions to the wave equation are obtained for slowly rotating black holes. In this approximation, the background geometry is treated as a perturbed Schwarzschild spacetime with the angular momentum per unit mass playing the role of a perturbative parameter. To first order in the angular momentum of the black hole, the scalar wave equation yields two coupled one-dimensional evolution equations for a function representing the scalar field in the Schwarzschild background and a second field that accounts for the rotation. Solutions to the wave equation are also obtained for rapidly rotating black holes. In this case, the wave equation does not admit complete separation of variables and yields a two-dimensional evolution equation. The study shows that, for rotating black holes, the late time dynamics of a massless scalar field exhibit the same power-law behavior as in the case of a Schwarzschild background independently of the angular momentum of the black hole.

W. Krivan; P. Laguna; P. Papadopoulos

1996-06-04T23:59:59.000Z

345

The (anti)correlation of the sub-mm and X-ray background sources  

E-Print Network [OSTI]

The connection between the sub-mm and the hard X-ray backgrounds is studied by comparing data at 2-10 keV and at 850um for a sample of 34 sources at fluxes (or limiting fluxes) which resolve most of the background in the two bands. These data were obtained with new SCUBA observations and by correlating data sets available from the literature. None of the 11 hard X-ray (2-10 keV) sources has a counterpart at 850um, with the exception of a faint Chandra source, which is a candidate type 2 QSO at high redshift. These data indicate that 2-10 keV sources brighter than 10^-15 erg s-1 cm-2, which make at least 75% of the background in this band, contribute for less than 7% to the submillimetric background. Out of the 24 SCUBA sources 23 are undetected by Chandra. These data indicate that most of these SCUBA sources must be powered either by starburst activity, or by an AGN which is obscured by a column Nh > 10^25 cm-2, with a reflection efficiency in the hard X-rays significantly lower than 1% in most cases.

P. Severgnini

2000-05-22T23:59:59.000Z

346

Early Nervous Systems: Theoretical background and a preliminary model of neuronal processes  

E-Print Network [OSTI]

Early Nervous Systems: Theoretical background and a preliminary model of neuronal processes Ot de cells evolved to connect pre-existing sensors and effectors. This proposal was strongly influenced brain as Holland (2003) called it, without fast and specialized connections between specific sensors

van Elburg, Ronald A.J.

347

SMART OCEANS BC Media Backgrounder From sensors to decisions when seconds count  

E-Print Network [OSTI]

SMART OCEANS BC ­ Media Backgrounder From sensors to decisions ­ when seconds count Introduction Oceans 2.0 and high speed, real-time analytics to monitor the #12;hundreds of sensors. Funding for Smart to develop fast event detection and enable a mobile Oceans 2.0 for use in geographically remote sensor

Pedersen, Tom

348

Investigating the Performance of Solar Air Conditioning Motivation/Background Findings  

E-Print Network [OSTI]

Investigating the Performance of Solar Air Conditioning Motivation/Background Findings Two Building-thermal collectors We investigated 3 types of solar cooling technologies: · Air conditioning consumes 10% of all conditioning can reduce energy consumption, only if paired with a suitable system · Conventional office air

349

Astroparticle Physics with a Customized Low-Background Broad Energy Germanium Detector  

E-Print Network [OSTI]

The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c^2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the MAJORANA Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.

MAJORANA Collaboration; C. E. Aalseth; M. Amman; F. T. Avignone III; H. O. Back; A. S. Barabash; P. S. Barbeau; M. Bergevin; F. E. Bertrand; M. Boswell; V. Brudanin; W. Bugg; T. H. Burritt; M. Busch; G. Capps; Y-D. Chan; J. I. Collar; R. J. Cooper; R. Creswick; J. A. Detwiler; J. Diaz; P. J. Doe; Yu. Efremenko; V. Egorov; H. Ejiri; S. R. Elliott; J. Ely; J. Esterline; H. Farach; J. E. Fast; N. Fields; P. Finnerty; B. Fujikawa; E. Fuller; V. M. Gehman; G. K. Giovanetti; V. E. Guiseppe; K. Gusey; A. L. Hallin; G. C Harper; R. Hazama; R. Henning; A. Hime; E. W. Hoppe; T. W. Hossbach; M. A. Howe; R. A. Johnson; K. J. Keeter; M. Keillor; C. Keller; J. D. Kephart; M. F. Kidd; A. Knecht; O. Kochetov; S. I. Konovalov; R. T. Kouzes; L. Leviner; J. C. Loach; P. N. Luke; S. MacMullin; M. G. Marino; R. D. Martin; D. -M. Mei; H. S. Miley; M. L. Miller; L. Mizouni; A. W. Meyers; M. Nomachi; J. L. Orrell; D. Peterson; D. G. Phillips II; A. W. P. Poon; G. Prior; J. Qian; D. C. Radford; K. Rielage; R. G. H. Robertson; L. Rodriguez; K. P. Rykaczewski; H. Salazar; A. G. Schubert; T. Shima; M. Shirchenko; D. Steele; J. Strain; G. Swift; K. Thomas; V. Timkin; W. Tornow; T. D. Van Wechel; I. Vanyushin; R. L. Varner; K. Vetter; J. F. Wilkerson; B. A. Wolfe; W. Xiang; E. Yakushev; H. Yaver; A. R. Young; C. -H. Yu; V. Yumatov; C. Zhang; S. Zimmerman

2010-07-20T23:59:59.000Z

350

Cosmogenic Production as a Background in Searching for Rare Physics Processes  

E-Print Network [OSTI]

We revisit calculations of the cosmogenic production rates for several long-lived isotopes that are potential sources of background in searching for rare physics processes such as the detection of dark matter and neutrinoless double-beta decay. Using updated cosmic-ray neutron flux measurements, we use TALYS 1.0 to investigate the cosmogenic activation of stable isotopes of several detector targets and find that the cosmogenic isotopes produced inside the target materials and cryostat can result in large backgrounds for dark matter searches and neutrinoless double-beta decay. We use previously published low-background HPGe data to constrain the production of $^{3}H$ on the surface and the upper limit is consistent with our calculation. We note that cosmogenic production of several isotopes in various targets can generate potential backgrounds for dark matter detection and neutrinoless double-beta decay with a massive detector, thus great care should be taken to limit and/or deal with the cosmogenic activation of the targets.

D. -M. Mei; Z. -B. Yin; S. R. Elliott

2009-03-12T23:59:59.000Z

351

Alpha Backgrounds for HPGe Detectors in Neutrinoless Double-Beta Decay Experiments  

E-Print Network [OSTI]

The Majorana Experiment will use arrays of enriched HPGe detectors to search for the neutrinoless double-beta decay of 76Ge. Such a decay, if found, would show lepton-number violation and confirm the Majorana nature of the neutrino. Searches for such rare events are hindered by obscuring backgrounds which must be understood and mitigated as much as possible. A potentially important background contribution to this and other double-beta decay experiments could come from decays of alpha-emitting isotopes in the 232Th and 238U decay chains on or near the surfaces of the detectors. An alpha particle emitted external to an HPGe crystal can lose energy before entering the active region of the detector, either in some external-bulk material or within the dead region of the crystal. The measured energy of the event will only correspond to a partial amount of the total kinetic energy of the alpha and might obscure the signal from neutrinoless double-beta decay. A test stand was built and measurements were performed to quantitatively assess this background. We present results from these measurements and compare them to simulations using Geant4. These results are then used to measure the alpha backgrounds in an underground detector in situ. We also make estimates of surface contamination tolerances for double-beta decay experiments using solid-state detectors.

R. A. Johnson; T. H. Burritt; S. R. Elliott; V. M. Gehman; V. E. Guiseppe; J. F. Wilkerson

2011-12-30T23:59:59.000Z

352

Charged lattice gas with a neutralizing background V. A. Levashov and M. F. Thorpe  

E-Print Network [OSTI]

to long-range Coulomb interactions, and overall charge neutrality is provided by a negative background. For a linear chain with infinite- range interactions, we use a devil's staircase formalism to obtain of the ordering of intercalated metal ions in positive electrodes of lithium batteries or in graphite. DOI: 10

Levashov, Valentin

353

Can Solar Neutrinos be a Serious Background in Direct Dark Matter Searches?  

E-Print Network [OSTI]

The coherent contribution of all neutrons in neutrino nucleus scattering due to the neutral current is examined considering the boron solar neutrinos. These neutrinos could potentially become a source of background in the future dark matter searches aiming at nucleon cross sections in the region well below the few events per ton per year.

J. D. Vergados; H. Ejiri

2008-05-30T23:59:59.000Z

354

BACKGROUND REPORTS FOR THE CALIFORNIA CARBON CAPTURE AND STORAGE REVIEW PANEL  

E-Print Network [OSTI]

BACKGROUND REPORTS FOR THE CALIFORNIA CARBON CAPTURE AND STORAGE REVIEW PANEL Prepared by the Technical Advisory Team in support of The California Carbon Capture and Storage Review Panel 12 Carbon Capture and Storage Review Panel Contents 1. Overview of the Carbon Capture and Storage Panel

355

Measuring the Solar Diameter with a Michelson Radio Interferometer 1. Scientific Background  

E-Print Network [OSTI]

3, M4, mirrors; a, 100-inch paraboloidal primary mirror; b convex secondary mirror; c, coud´e flatMeasuring the Solar Diameter with a Michelson Radio Interferometer 1. Scientific Background pick-off mirror; d, focus. Figures from Michelson & Pease (1921). A work-around the diffraction

Metchev, Stanimir

356

Investigation of the hard x-ray background in backlit pinhole imagers  

SciTech Connect (OSTI)

Hard x-rays from laser-produced hot electrons (>10 keV) in backlit pinhole imagers can give rise to a background signal that decreases signal dynamic range in radiographs. Consequently, significant uncertainties are introduced to the measured optical depth of imaged plasmas. Past experiments have demonstrated that hard x-rays are produced when hot electrons interact with the high-Z pinhole substrate used to collimate the softer He-? x-ray source. Results are presented from recent experiments performed on the OMEGA-60 laser to further study the production of hard x-rays in the pinhole substrate and how these x-rays contribute to the background signal in radiographs. Radiographic image plates measured hard x-rays from pinhole imagers with Mo, Sn, and Ta pinhole substrates. The variation in background signal between pinhole substrates provides evidence that much of this background comes from x-rays produced in the pinhole substrate itself. A Monte Carlo electron transport code was used to model x-ray production from hot electrons interacting in the pinhole substrate, as well as to model measurements of x-rays from the irradiated side of the targets, recorded by a bremsstrahlung x-ray spectrometer. Inconsistencies in inferred hot electron distributions between the different pinhole substrate materials demonstrate that additional sources of hot electrons beyond those modeled may produce hard x-rays in the pinhole substrate.

Fein, J. R., E-mail: jrfein@umich.edu; Holloway, J. P. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143 (United States); Peebles, J. L. [Center for Energy Research, University of California, San Diego, La Jolla, California 92093 (United States); Keiter, P. A.; Klein, S. R.; Kuranz, C. C.; Manuel, M. J.-E.; Drake, R. P. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143 (United States)

2014-11-15T23:59:59.000Z

357

DC WRRC Report No. 103 Background Study of the Ground Water in  

E-Print Network [OSTI]

Leaching 51 5.0. FILLINGS 51 5.1 Background Infonnation 51 5.2 Special Research Needs 54 6.0. CONCLUSION. Area showing the General latitude and longitude. Figure 2. Fall line in the Middle Atlantic Region. Figure 3. Geologic section across the District of Columbia area, showing the succession and general

District of Columbia, University of the

358

The White Dwarf -- White Dwarf galactic background in the LISA data  

E-Print Network [OSTI]

LISA (Laser Interferometer Space Antenna) is a proposed space mission, which will use coherent laser beams exchanged between three remote spacecraft to detect and study low-frequency cosmic gravitational radiation. In the low-part of its frequency band, the LISA strain sensitivity will be dominated by the incoherent superposition of hundreds of millions of gravitational wave signals radiated by inspiraling white-dwarf binaries present in our own galaxy. In order to estimate the magnitude of the LISA response to this background, we have simulated a synthesized population that recently appeared in the literature. We find the amplitude of the galactic white-dwarf binary background in the LISA data to be modulated in time, reaching a minimum equal to about twice that of the LISA noise for a period of about two months around the time when the Sun-LISA direction is roughly oriented towards the Autumn equinox. Since the galactic white-dwarfs background will be observed by LISA not as a stationary but rather as a cyclostationary random process with a period of one year, we summarize the theory of cyclostationary random processes, present the corresponding generalized spectral method needed to characterize such process, and make a comparison between our analytic results and those obtained by applying our method to the simulated data. We find that, by measuring the generalized spectral components of the white-dwarf background, LISA will be able to infer properties of the distribution of the white-dwarfs binary systems present in our Galaxy.

Jeffrey A. Edlund; Massimo Tinto; Andrzej Krolak; Gijs Nelemans

2005-04-22T23:59:59.000Z

359

Nonlinear plasma waves excitation by intense ion beams in background plasma  

E-Print Network [OSTI]

describe the plasma perturbations well.5 Here, we focus on the general case where the plasma density hasNonlinear plasma waves excitation by intense ion beams in background plasma Igor D. Kaganovich, Edward A. Startsev, and Ronald C. Davidson Plasma Physics Laboratory, Princeton University, Princeton

Kaganovich, Igor

360

Alpha Backgrounds for HPGe Detectors in Neutrinoless Double-Beta Decay Experiments  

SciTech Connect (OSTI)

The Majorana Experiment will use arrays of enriched HPGe detectors to search for the neutrinoless double-beta decay of 76Ge. Such a decay, if found, would show lepton-number violation and confirm the Majorana nature of the neutrino. Searches for such rare events are hindered by obscuring backgrounds which must be understood and mitigated as much as possible. A potentially important background contribution to this and other double-beta decay experiments could come from decays of alpha-emitting isotopes in the 232Th and 238U decay chains on or near the surfaces of the detectors. An alpha particle emitted external to an HPGe crystal can lose energy before entering the active region of the detector, either in some external-bulk material or within the dead region of the crystal. The measured energy of the event will only correspond to a partial amount of the total kinetic energy of the alpha and might obscure the signal from neutrinoless double-beta decay. A test stand was built and measurements were performed to quantitatively assess this background. We present results from these measurements and compare them to simulations using Geant4. These results are then used to measure the alpha backgrounds in an underground detector in situ. We also make estimates of surface contamination tolerances for double-beta decay experiments using solid-state detectors.

Johnson, R. A. [University of Washington, Seattle; Burritt, T. H. [University of Washington, Seattle; Elliott, S. R. [Los Alamos National Laboratory (LANL); Gehman, V. M. [Los Alamos National Laboratory (LANL); Guiseppe, V.E. [University of South Dakota; Wilkerson, J. F. [UNC/Triangle Univ. Nucl. Lab, Durham, NC/ORNL

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Astroparticle physics with a customized low-background broad energy Germanium detector  

SciTech Connect (OSTI)

The Majorana Collaboration is building the Majorana Demonstrator, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The Majorana Demonstrator will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c{sup 2} mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the Majorana Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.

Aalseth, Craig E.; Amman, M.; Avignone, Frank T.; Back, Henning O.; Barabash, Alexander S.; Barbeau, P. S.; Bergevin, M.; Bertrand, F.; Boswell, M.; Brudanin, V.; Bugg, William; Burritt, Tom H.; Busch, Matthew; Capps, Greg L.; Chan, Yuen-Dat; Collar, J. I.; Cooper, R. J.; Creswick, R.; Detwiler, Jason A.; Diaz, J.; Doe, Peter J.; Efremenko, Yuri; Egorov, Viatcheslav; Ejiri, H.; Elliott, Steven R.; Ely, James H.; Esterline, James H.; Farach, H. A.; Fast, James E.; Fields, N.; Finnerty, P.; Fujikawa, Brian; Fuller, Erin S.; Gehman, Victor M.; Giovanetti, G. K.; Guiseppe, Vincente; Gusey, K.; Hallin, A. L.; Harper, Gregory; Hazama, R.; Henning, Reyco; Hime, Andrew; Hoppe, Eric W.; Hossbach, Todd W.; Howe, M. A.; Johnson, R. A.; Keeter, K.; Keillor, Martin E.; Keller, C.; Kephart, Jeremy D.; Kidd, Mary; Knecht, A.; Kochetov, Oleg; Konovalov, S.; Kouzes, Richard T.; Leviner, L.; Loach, J. C.; Luke, P.; MacMullin, S.; Marino, Michael G.; Martin, R. D.; Mei, Dong-Ming; Miley, Harry S.; Miller, M. L.; Mizouni, Leila; Myers, Allan W.; Nomachi, Masaharu; Orrell, John L.; Peterson, David; Phillips, D.; Poon, Alan; Prior, Gersende; Qian, J.; Radford, D. C.; Rielage, Keith; Robertson, R. G. H.; Rodriguez, Larry; Rykaczewski, Krzysztof P.; Salazar, Harold; Schubert, Alexis G.; Shima, T.; Shirchenko, M.; Steele, David; Strain, J.; Swift, Gary; Thomas, K.; Timkin, V.; Tornow, W.; Van Wechel, T. D.; Vanyushin, I.; Varner, R. L.; Vetter, Kai; Wilkerson, J. F.; Wolfe, B. A.; Xiang, W.; Yakushev, E.; Yaver, Harold; Young, A.; Yu, Chang-Hong; Yumatov, Vladimir; Zhang, C.; Zimmerman, S.

2011-10-01T23:59:59.000Z

362

Alpha Backgrounds and Their Implications for Neutrinoless Double-Beta Decay Experiments Using HPGe Detectors  

E-Print Network [OSTI]

Alpha Backgrounds and Their Implications for Neutrinoless Double-Beta Decay Experiments Using HPGe and Their Implications for Neutrinoless Double-Beta Decay Experiments Using HPGe Detectors Robert A. Johnson Chair of the Supervisory Committee: Professor John F. Wilkerson Physics The observation of neutrinoless double-beta decay

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

363

Evaluation of ultra-low background materials for uranium and thorium using ICP-MS  

SciTech Connect (OSTI)

An increasing number of physics experiments require low background materials for their construction. The presence of Uranium and Thorium and their progeny in these materials present a variety of unwanted background sources for these experiments. The sensitivity of the experiments continues to drive the necessary levels of detection ever lower as well. This requirement for greater sensitivity has rendered direct radioassay impractical in many cases requiring large quantities of material, frequently many kilograms, and prolonged counting times, often months. Other assay techniques have been employed such as Neutron Activation Analysis but this requires access to expensive facilities and instrumentation and can be further complicated and delayed by the formation of unwanted radionuclides. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a useful tool and recent advancements have increased the sensitivity particularly in the elemental high mass range of U and Th. Unlike direct radioassay, ICP-MS is a destructive technique since it requires the sample to be in liquid form which is aspirated into a high temperature plasma. But it benefits in that it usually requires a very small sample, typically about a gram. This paper discusses how a variety of low background materials such as copper, polymers, and fused silica are made amenable to ICP-MS assay and how the arduous task of maintaining low backgrounds of U and Th is achieved.

Hoppe, E. W.; Overman, N. R.; LaFerriere, B. D. [Pacific Northwest National Laboratory, Richland, WA 99354 (United States)] [Pacific Northwest National Laboratory, Richland, WA 99354 (United States)

2013-08-08T23:59:59.000Z

364

Evaluation of Ultra-Low Background Materials for Uranium and Thorium Using ICP-MS  

SciTech Connect (OSTI)

An increasing number of physics experiments require low background materials for their construction. The presence of Uranium and Thorium and their progeny in these materials present a variety of unwanted background sources for these experiments. The sensitivity of the experiments continues to drive the necessary levels of detection ever lower as well. This requirement for greater sensitivity has rendered direct radioassay impractical in many cases requiring large quantities of material, frequently many kilograms, and prolonged counting times, often months. Other assay techniques have been employed such as Neutron Activation Analysis but this requires access to expensive facilities and instrumentation and can be further complicated and delayed by the formation of unwanted radionuclides. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a useful tool and recent advancements have increased the sensitivity particularly in the elemental high mass range of U and Th. Unlike direct radioassay, ICP-MS is a destructive technique since it requires the sample to be in liquid form which is aspirated into a high temperature plasma. But it benefits in that it usually requires a very small sample, typically about a gram. Here we will discuss how a variety of low background materials such as copper, polymers, and fused silica are made amenable to ICP-MS assay and how the arduous task of maintaining low backgrounds of U and Th is achieved.

Hoppe, Eric W.; Overman, Nicole R.; LaFerriere, Brian D.

2013-08-08T23:59:59.000Z

365

Electrical axes of TESLA-type cavities (Theoretical background, development of measurement equipment, measurement results)  

E-Print Network [OSTI]

- 1 - Electrical axes of TESLA-type cavities (Theoretical background, development of measurement equipment, measurement results) Anton Labanc, MHF-SL, DESY, January 2008 Abstract Cells in TESLA cavities. A short overview was already published at the TESLA Report 2007-01. This paper brings more details about

366

Fractal Structure of Isothermal Lines and Loops on the Cosmic Microwave Background  

E-Print Network [OSTI]

Fractal Structure of Isothermal Lines and Loops on the Cosmic Microwave Background Naoki KOBAYASHI and the fractal structure is confirmed in the radiation temperature fluctuation. We estimate the fractal exponents, such as the fractal dimension De of the entire pattern of isothermal lines, the fractal dimension Dc of a single

Chiang, Lung-Yih

367

Background: Global Warming, 2009 1. Unequivocally, the climate is warming. Natural systems are affected.  

E-Print Network [OSTI]

Background: Global Warming, 2009 1. Unequivocally, the climate is warming. Natural systems are affected. 2. Very likely (>90% certainty), humans are causing most of the warming. 3. No single technology are very likely to impose net annual costs, which will increase over time as global temperatures increase

Minnesota, University of

368

Experimental and theoretical studies of particle generation afterlaser ablation of copper with background gas at atmosphericpressure  

SciTech Connect (OSTI)

Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the condensed aerosol plume were observed in two background gases, helium and argon. The primary particle shape and size distribution were measured using a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a differential mobility analyzer (DMA). The gas dynamics simulation included nucleation and coagulation within the vapor plume, heat and mass transfer from the vapor plume to the background gas, and heat transfer to the sample. The experimental data and the calculated evolution of the shape of the vapor plume showed the same trend for the spatial distribution of the condensed particles in both background gases. The simulated particle size distribution also qualitatively agreed with the experimental data. It was determined that the laser energy, the physical properties of the background gas (conductivity, diffusivity and viscosity), and the shape of the ablation system (ablation chamber and the layout of the sample) have strong effects on the condensation process and the subsequent sizes, shapes and degree of aggregation of the particles.

Wen, Sy-Bor; Mao, Xianglei; Greif, Ralph; Russo, Richard E.

2007-05-31T23:59:59.000Z

369

Inferring Propagation Direction of Nonlinear Internal Waves in a Vertically Sheared Background Flow  

E-Print Network [OSTI]

Inferring Propagation Direction of Nonlinear Internal Waves in a Vertically Sheared Background Flow are resistant to heaving. The beamwise method provides accurate predictions of wave propagation angle for cases 2005). Determining the wave propagation di- rection, so that one may in turn identify potential lo

Kelley, Dan

370

4.0 Inventory of Existing Programs and Activities 4.1 Background  

E-Print Network [OSTI]

172 4.0 Inventory of Existing Programs and Activities 4.1 Background The Blackfoot Subbasin Inventory summarizes current fish, wildlife, and habitat protection and restoration activities within the subbasin. The Inventory includes a description of 1) protected areas in the subbasin, 2) management plans

371

Criminal Background Check Request Form revised 08/13/2013 #404 Page 1 of 2  

E-Print Network [OSTI]

: Recruitment & Workforce Planning MS 1255 jobpath@tamu.edu Fax (979) 847-8877 NEED HELP? Recruitment & Workforce Planning Phone (979) 845-5154 jobpath@tamu.edu #12;Criminal Background Check Request Form revised-google-email-account.html It is important you read, understand and comply with following information: Recruitment and Workforce Planning

Boas, Harold P.

372

Shock Acceleration of the Energetic Particle Background in the Solar Wind David T. Sodaitis  

E-Print Network [OSTI]

Shock Acceleration of the Energetic Particle Background in the Solar Wind David T. Sodaitis Physics Department, University of New Hampshire Durham, New Hampshire, USA sodaitis@cisunix.unh.edu ABSTRACT Lee with solar energetic particle (SEP) events (Desai et al. 2003) have shown that shock acceleration may act

373

1. BACKGROUND & OBJECTIVES For geological carbon sequestration, it is essential to  

E-Print Network [OSTI]

1. BACKGROUND & OBJECTIVES · For geological carbon sequestration, it is essential to understand Material Characterization for Intermediate-scale Testing to Develop Strategies for Geologic Sequestration to generate comprehensive data sets. Due to the nature of the CO2 geological sequestration where supercritical

374

STATISTICS OF EXTREMES IN CLIMATOLOGY AND HYDROLOGY PART I: BACKGROUND AND TRADITIONAL APPROACHES  

E-Print Network [OSTI]

1 STATISTICS OF EXTREMES IN CLIMATOLOGY AND HYDROLOGY PART I: BACKGROUND AND TRADITIONAL APPROACHES;3 Outline (1) Historical Perspective (2) Basic Characteristics of Climate/Hydrologic Extremes (3) Traditional Statistical Analysis of Climate/Hydrologic Extremes (4) Spatial/Temporal Dependence of Climate

Katz, Richard

375

Estimation of Cosmic Induced Contamination in Ultra-low Background Detector Materials  

SciTech Connect (OSTI)

Executive Summary This document presents the result of investigating a way to reliably determine cosmic induced backgrounds for ultra-low background materials. In particular, it focuses on those radioisotopes produced by the interactions with cosmic ray particles in the detector materials that act as a background for experiments looking for neutrinoless double beta decay. This investigation is motivated by the desire to determine background contributions from cosmic ray activation of the electroformed copper that is being used in the construction of the MAJORANA DEMONSTRATOR. The most important radioisotope produced in copper that contributes to the background budget is 60Co, which has the potential to deposit energy in the region of interest of this experiment. Cobalt-60 is produced via cosmic ray neutron collisions in the copper. This investigation aims to provide a method for determining whether or not the copper has been exposed to cosmic radiation beyond the threshold which the Majorana Project has established as the maximum exposure. This threshold is set by the Project as the expected contribution of this source of background to the overall background budget. One way to estimate cosmic ray neutron exposure of materials on the surface of the Earth is to relate it to the cosmic ray muon exposure. Muons are minimum-ionizing particles and the available technologies to detect muons are easier to implement than those to detect neutrons. We present the results of using a portable, ruggedized muon detector, the -Witness made by our research group, for determination of muon exposure of materials for the MAJORANA DEMONSTRATOR. From the muon flux measurement, this report presents a method to estimate equivalent sea-level exposure, and then infer the neutron exposure of the tracked material and thus the cosmogenic activation of the copper. This report combines measurements of the muon flux taken by the -Witness detector with Geant4 simulations in order to assure our understanding of the -Witness prototype. As a proof of concept, we present the results of using this detector with electroformed copper during its transport from Pacific Northwest National Laboratory, where the copper is grown, to the underground lab in Lead, South Dakota, where the experiment is being deployed. The development of a code to be used with the Majorana parts tracking database, designed to aid in estimating the cosmogenic activation, is also presented.

Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Orrell, John L.; Berguson, Timothy J.; Greene, Austen T.

2012-08-01T23:59:59.000Z

376

Neutron Inelastic Scattering Processes as Background for Double-Beta Decay Experiments  

E-Print Network [OSTI]

We investigate several Pb$(n,n'\\gamma$) and Ge$(n,n'\\gamma$) reactions. We measure $\\gamma$-ray production from Pb$(n,n'\\gamma$) reactions that can be a significant background for double-beta decay experiments which use lead as a massive inner shield. Particularly worrisome for Ge-based double-beta decay experiments are the 2041-keV and 3062-keV $\\gamma$ rays produced via Pb$(n,n'\\gamma$). The former is very close to the ^{76}Ge double-beta decay endpoint energy and the latter has a double escape peak energy near the endpoint. Excitation $\\gamma$-ray lines from Ge$(n,n'\\gamma$) reactions are also observed. We consider the contribution of such backgrounds and their impact on the sensitivity of next-generation searches for neutrinoless double-beta decay using enriched germanium detectors.

D. -M. Mei; S. R. Elliott; A. Hime; V. Gehman; K. Kazkaz

2008-01-26T23:59:59.000Z

377

Gamma-Ray Bursts, Ultra High Energy Cosmic Rays, and Cosmic Gamma-Ray Background  

E-Print Network [OSTI]

We argue that gamma-ray bursts (GRBs) may be the origin of the cosmic gamma-ray background radiation observed in GeV range. It has theoretically been discussed that protons may carry a much larger amount of energy than electrons in GRBs, and this large energy can be radiated in TeV range by synchrotron radiation of ultra-high-energy protons (\\sim 10^{20} eV). The possible detection of GRBs above 10 TeV suggested by the Tibet and HEGRA groups also supports this idea. If this is the case, most of TeV gamma-rays from GRBs are absorbed in intergalactic fields and eventually form GeV gamma-ray background, whose flux is in good agreement with the recent observation.

Tomonori Totani

1999-04-13T23:59:59.000Z

378

Origin of background electron concentration in InxGa1-xN alloys  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

The origin of high background electron concentration (n) in InxGa1-xN alloys has been investigated. A shallow donor was identified as having an energy level (ED1) that decreases with x (ED1 = 16 meV at x = 0 and ED1 = 0 eV at x ~ 0.5) and that crossover the conduction band at x ~ 0.5. This shallow donor is believed to be the most probable cause of high n in InGaN. This understanding is consistent with the fact that n increases sharply with an increase in x and becomes constant for x > 0.5. A continuous reduction in n was obtained by increasing the V/III ratio during the epilayer growth, suggesting that nitrogen vacancy-related impurities are a potential cause of the shallow donors and high background electron concentration in InGaN

Pantha, B. N.; Wang, H.; Khan, N.; Lin, J. Y.; Jiang, H. X.

2011-08-01T23:59:59.000Z

379

A Shallow Underground Laboratory for Low-Background Radiation Measurements and Materials Development  

SciTech Connect (OSTI)

Abstract: Pacific Northwest National Laboratory recently commissioned a new shallow underground laboratory, located at a depth of approximately 30 meters water-equivalent. This new addition to the small class of radiation measurement laboratories located at modest underground depths worldwide houses the latest generation of custom-made, high-efficiency, low-background gamma-ray spectrometers and gas proportional counters. This manuscript describes the unique capabilities present in the shallow underground laboratory; these include large-scale ultra-pure materials production and a suite of radiation detection systems. Reported data characterize the degree of background reduction achieved through a combination of underground location, graded shielding, and rejection of cosmic-ray events. We conclude by presenting measurement targets and future opportunities.

Aalseth, Craig E.; Bonicalzi, Ricco; Cantaloub, Michael G.; Day, Anthony R.; Erikson, Luke E.; Fast, James E.; Forrester, Joel B.; Fuller, Erin S.; Glasgow, Brian D.; Greenwood, Lawrence R.; Hoppe, Eric W.; Hossbach, Todd W.; Hyronimus, Brian J.; Keillor, Martin E.; Mace, Emily K.; McIntyre, Justin I.; Merriman, Jason H.; Myers, Allan W.; Overman, Cory T.; Overman, Nicole R.; Panisko, Mark E.; Seifert, Allen; Warren, Glen A.; Runkle, Robert C.

2012-11-08T23:59:59.000Z

380

Empirical Correction of Crosstalk in a Low-Background Germanium ?? Analysis System  

SciTech Connect (OSTI)

ABSTRACT The Pacific Northwest National Laboratory is currently developing a custom software suite capable of automating many of the tasks required to accurately analyze coincident signals within gamma spectrometer arrays. During the course of this work, significant crosstalk was identified in the energy determination for spectra collected with a new low-background intrinsic germanium (HPGe) array at PNNL. The HPGe array is designed for high detection efficiency, ultra-low-background performance, and sensitive gamma gamma coincidence detection. The first half of the array, a single cryostat containing 7 HPGe crystals, was recently installed into a new shallow underground laboratory facility. This update will present a brief review of the germanium array, describe the observed crosstalk, and present a straight-forward empirical correction that significantly reduces the impact of this crosstalk on the spectroscopic performance of the system.

Keillor, Martin E.; Erikson, Luke E.; Aalseth, Craig E.; Day, Anthony R.; Fuller, Erin S.; Glasgow, Brian D.; Hoppe, Eric W.; Hossbach, Todd W.; Mizouni, Leila K.; Myers, Allan W.; Overman, Cory T.; Seifert, Allen; Stavenger, Timothy J.

2013-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

AN EFFICIENT APPROXIMATION TO THE LIKELIHOOD FOR GRAVITATIONAL WAVE STOCHASTIC BACKGROUND DETECTION USING PULSAR TIMING DATA  

SciTech Connect (OSTI)

Direct detection of gravitational waves by pulsar timing arrays will become feasible over the next few years. In the low frequency regime (10{sup -7} Hz-10{sup -9} Hz), we expect that a superposition of gravitational waves from many sources will manifest itself as an isotropic stochastic gravitational wave background. Currently, a number of techniques exist to detect such a signal; however, many detection methods are computationally challenging. Here we introduce an approximation to the full likelihood function for a pulsar timing array that results in computational savings proportional to the square of the number of pulsars in the array. Through a series of simulations we show that the approximate likelihood function reproduces results obtained from the full likelihood function. We further show, both analytically and through simulations, that, on average, this approximate likelihood function gives unbiased parameter estimates for astrophysically realistic stochastic background amplitudes.

Ellis, J. A.; Siemens, X. [Center for Gravitation, Cosmology and Astrophysics, University of Wisconsin Milwaukee, Milwaukee, WI 53211 (United States); Van Haasteren, R. [Max-Planck-Institut fuer Gravitationphysik (Albert-Einstein-Institut), D-30167 Hanover (Germany)

2013-05-20T23:59:59.000Z

382

MaGe - a Geant4-based Monte Carlo framework for low-background experiments  

E-Print Network [OSTI]

A Monte Carlo framework, MaGe, has been developed based on the Geant4 simulation toolkit. Its purpose is to simulate physics processes in low-energy and low-background radiation detectors, specifically for the Majorana and Gerda $^{76}$Ge neutrinoless double-beta decay experiments. This jointly-developed tool is also used to verify the simulation of physics processes relevant to other low-background experiments in Geant4. The MaGe framework contains simulations of prototype experiments and test stands, and is easily extended to incorporate new geometries and configurations while still using the same verified physics processes, tunings, and code framework. This reduces duplication of efforts and improves the robustness of and confidence in the simulation output.

Yuen-Dat Chan; Jason A. Detwiler; Reyco Henning; Victor M. Gehman; Rob A. Johnson; David V. Jordan; Kareem Kazkaz; Markus Knapp; Kevin Kroninger; Daniel Lenz; Jing Liu; Xiang Liu; Michael G. Marino; Akbar Mokhtarani; Luciano Pandola; Alexis G. Schubert; Claudia Tomei

2008-02-06T23:59:59.000Z

383

Apparatus having reduced background for measuring radiation activity in aerosol particles  

DOE Patents [OSTI]

Apparatus having reduced background for measuring radiation activity in aerosol particles. A continuous air monitoring sampler is described for use in detecting the presence of alpha-emitting aerosol particles. An inlet fractionating screen has been demonstrated to remove about 95% of freshly formed radon progeny from the aerosol sample, and approximately 33% of partially aged progeny. Addition of an electrical condenser and a modified dichotomous virtual impactor are expected to produce considerable improvement in these numbers, the goal being to enrich the transuranic (TRU) fraction of the aerosols. This offers the possibility of improving the signal-to-noise ratio for the detected alpha-particle energy spectrum in the region of interest for detecting TRU materials associated with aerosols, thereby enhancing the performance of background-compensation algorithms for improving the quality of alarm signals intended to warn personnel of potentially harmful quantities of TRU materials in the ambient air.

Rodgers, John C. (Santa Fe, NM); McFarland, Andrew R. (College Station, TX); Oritz, Carlos A. (Bryan, TX); Marlow, William H. (College Station, TX)

1992-01-01T23:59:59.000Z

384

THE HIGH BACKGROUND RADIATION AREA IN RAMSAR IRAN: GEOLOGY, NORM, BIOLOGY, LNT, AND POSSIBLE REGULATORY FUN  

SciTech Connect (OSTI)

The city of Ramsar Iran hosts some of the highest natural radiation levels on earth, and over 2000 people are exposed to radiation doses ranging from 1 to 26 rem per year. Curiously, inhabitants of this region seem to have no greater incidence of cancer than those in neighboring areas of normal background radiation levels, and preliminary studies suggest their blood cells experience fewer induced chromosomal abnormalities when exposed to 150 rem ''challenge'' doses of radiation than do the blood cells of their neighbors. This paper will briefly describe the unique geology that gives Ramsar its extraordinarily high background radiation levels. It will then summarize the studies performed to date and will conclude by suggesting ways to incorporate these findings (if they are borne out by further testing) into future radiation protection standards.

Karam, P. A.

2002-02-25T23:59:59.000Z

385

Alternative treaty monitoring approaches using ultra-low background measurement technology  

SciTech Connect (OSTI)

The International Monitoring System (IMS) of the Comprehensive Test Ban Treaty includes a network of stations and laboratories for collection and analysis of radioactive aerosols. Alternative approaches to IMS operations are considered as a method of enhancing treaty verification. Ultra-low background (ULB) detection promises the possibility of improvements to IMS minimum detectable activities (MDAs) well below the current approach, requiring MDAp30 mBq/m3 of air for 140Ba, or about 106 fissions per daily sample.

Miley, Harry S.; Aalseth, Craig E.; Bowyer, Ted W.; Fast, James E.; Hayes, James C.; Hoppe, Eric W.; Hossbach, Todd W.; Keillor, Martin E.; Kephart, Jeremy D.; McIntyre, Justin I.; Seifert, Allen

2009-05-01T23:59:59.000Z

386

A novel approach to background reduction in double beta decay experiments  

E-Print Network [OSTI]

Active background reduction in high resolution calorimeters is a promising approach to achieve ultimate sensitivity in neutrinoless double beta decay experiments. We propose Cerenkov emission from beta rays in bolometric crystals as a viable alternative to scintillation. This novel approach could broaden the range of materials of interest for calorimetric searches of the double beta decay. We discuss the optical properties of TeO$_2$ crystals, as a show case.

T. Tabarelli de Fatis

2009-08-02T23:59:59.000Z

387

Position and frequency shifts induced by massive modes of the gravitational wave background in alternative gravity  

SciTech Connect (OSTI)

Alternative theories of gravity predict the presence of massive scalar, vector, and tensor gravitational wave modes in addition to the standard massless spin 2 graviton of general relativity. The deflection and frequency shift effects on light from distant sources propagating through a stochastic background of gravitational waves, containing such modes, differ from their counterparts in general relativity. Such effects are considered as a possible signature for alternative gravity in attempts to detect deviations from Einstein's gravity by astrophysical means.

Bellucci, Stefano [INFN Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044 Frascati (Italy); Capozziello, Salvatore; De Laurentis, Mariafelicia [Dip. di Scienze Fisiche, Universita di Napoli 'Federico II' and INFN Sez. di Napoli, Compl. Universitario Monte S. Angelo, Ed. N, Via Cinthia, I-80126 Napoli (Italy); Faraoni, Valerio [Physics Department, Bishop's University, Sherbrooke, Quebec, Canada J1M 1Z7 (Canada)

2009-05-15T23:59:59.000Z

388

Towards a proof of the equivalence between FRW background expansion and statistical isotropy  

E-Print Network [OSTI]

We will expose in this paper our advances towards a proof of the equivalence between FRW background expansion, during some period of time that contains primordial inflation, and the statistical isotropy of the primordial curvature perturbation $\\zeta$ at the end of this period of time. Our motivation rests on the growing interest in the existence of a preferred direction in the Universe hinted by the continuous presence of anomalies in the CMB data.

Rodriguez, Yeinzon; Nieto, Carlos M

2015-01-01T23:59:59.000Z

389

Quantum mechanics of a charged particle in a background magnetic field interacting with linearized gravitational waves  

E-Print Network [OSTI]

We consider the dynamics of a charged particle interacting with background electromagnetic field under the influence of linearized gravitational waves in the long wave-length and low-velocity limit. Following the prescription in \\cite{speli}, the system is quantized and the Hamiltonian is then solved by using standard algebraic iterative methods. The solution is in conformity with the classical analysis and shows the possibility of tuning the frequency by changing the magnetic field to set up resonance.

Sunandan Gangopadhyay; Anirban Saha

2012-04-02T23:59:59.000Z

390

Harmonic oscillator in a background magnetic field in noncommutative quantum phase-space  

E-Print Network [OSTI]

We solve explicitly the two-dimensional harmonic oscillator and the harmonic oscillator in a background magnetic field in noncommutative phase-space without making use of any type of representation. A key observation that we make is that for a specific choice of the noncommutative parameters, the time reversal symmetry of the systems get restored since the energy spectrum becomes degenerate. This is in contrast to the noncommutative configuration space where the time reversal symmetry of the harmonic oscillator is always broken.

Joseph Ben Geloun; Sunandan Gangopadhyay; Frederik G Scholtz

2009-01-22T23:59:59.000Z

391

Identification and summary characterization of materials potentially requiring vitrification: Background information  

SciTech Connect (OSTI)

This document contains background information for the Workshop in general and the presentation entitled `Identification and Summary Characterization of Materials Potentially Requiring Vitrification` that was given during the first morning of the workshop. summary characteristics of 9 categories of US materials having some potential to be vitrified are given. This is followed by a 1-2 page elaborations for each of these 9 categories. References to more detailed information are included.

Croff, A.G.

1996-05-13T23:59:59.000Z

392

Decay of Dirac Massive Hair in the Background of Spherical Black Hole  

E-Print Network [OSTI]

The intermediate and late-time behaviour of massive Dirac hair in the static spherically symmetric black hole spacetime was studied. It was revealed that the intermediate asymptotic pattern of decay of massive Dirac spinor hair is dependent on the mass of the field under consideration as well as the multiple number of the wave mode. The long-lived oscillatory tail observed at timelike infinity in the considered background decays slowly as t^{-5/6}.

Rafa? Moderski; Marek Rogatko

2008-05-06T23:59:59.000Z

393

The origin of the cosmic gamma-ray background in the MeV range  

E-Print Network [OSTI]

There has been much debate about the origin of the diffuse gamma--ray background in the energy range from a few hundred keV to 10 MeV. At lower energies, AGNs and Seyfert galaxies can explain the background, but their contribution cuts off above $\\simeq$ 0.3 MeV. In the MeV range, the spectrum drops sharply for increasing energies. It flattens beyond $\\sim$ 10 MeV, and blazars appear to account for the fluxes observed there. That leaves an unexplained window for which different candidate sources have been proposed, including annihilations of weakly interacting massive particles (WIMPS). One candidate are Type Ia supernovae (SNe Ia). Previous estimates of SNe Ia to the cosmic gamma--ray background were based on a restricted number of SN Ia explosion models and, on very limited measurements of the SN Ia rates as a function of redshift $z$. In the present work, we use a wide variety of explosion models and the most recent measurements of the SN Ia rates, which now cover a wide redshift interval. If we adopt the ...

Ruiz-Lapuente, Pilar; Hartmann, Dieter; Ajello, Marco; Canal, Ramon; Rpke, Friedrich K; Ohlmann, Sebastian T; Hillebrandt, Wolfgang

2015-01-01T23:59:59.000Z

394

Ship Effect Neutron Measurements And Impacts On Low-Background Experiments  

SciTech Connect (OSTI)

The primary particles entering the upper atmosphere as cosmic rays create showers in the atmosphere that include a broad spectrum of secondary neutrons, muons and protons. These cosmic-ray secondaries interact with materials at the surface of the Earth, yielding prompt backgrounds in radiation detection systems, as well as inducing long-lived activities through spallation events, dominated by the higher-energy neutron secondaries. For historical reasons, the multiple neutrons produced in spallation cascade events are referred to as ship effect neutrons. Quantifying the background from cosmic ray induced activities is important to low-background experiments, such as neutrino-less double beta decay. Since direct measurements of the effects of shielding on the cosmic-ray neutron spectrum are not available, Monte Carlo modeling is used to compute such effects. However, there are large uncertainties (orders of magnitude) in the possible cross-section libraries and the cosmic-ray neutron spectrum for the energy range needed in such calculations. The measurements reported here were initiated to validate results from Monte Carlo models through experimental measurements in order to provide some confidence in the model results. The results indicate that the models provide the correct trends of neutron production with increasing density, but there is substantial disagreement between the model and experimental results for the lower-density materials of Al, Fe and Cu.

Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Siciliano, Edward R.

2013-10-01T23:59:59.000Z

395

IS THERE AN UNACCOUNTED FOR EXCESS IN THE EXTRAGALACTIC COSMIC RADIO BACKGROUND?  

SciTech Connect (OSTI)

Analyses of the distribution of absolute brightness temperature over the radio sky have recently led to suggestions that there exists a substantial unexplained extragalactic radio background. Consequently, there have been numerous attempts to place constraints on plausible origins of this 'excess'. We suggest here that this expectation of a large extragalactic background, over and above that contributed by the sources observed in the surveys, is based on an extremely simple geometry adopted to model the Galactic emission and the procedure adopted in the estimation of the extragalactic contribution. In this paper, we derive the extragalactic radio background from wide-field radio images using a more realistic modeling of the Galactic emission and decompose the sky maps at 150, 408, and 1420 MHz into anisotropic Galactic and isotropic extragalactic components. The anisotropic Galactic component is assumed to arise from a highly flattened spheroid representing the thick disk, embedded in a spherical halo, both centered at the Galactic center, along with Galactic sources, filamentary structures, and Galactic loops and spurs. All components are constrained to be positive and the optimization scheme minimizes the sky area occupied by the complex filaments. We show that in contrast with simple modeling of Galactic emission as a plane parallel slab, the more realistic modeling yields estimates for the uniform extragalactic brightness that are consistent with expectations from known extragalactic radio source populations.

Subrahmanyan, Ravi [Raman Research Institute, CV Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Cowsik, Ramanath, E-mail: rsubrahm@rri.res.in, E-mail: cowsik@physics.wustl.edu [Physics Department and McDonnell Center for the Space Sciences, Washington University, Campus Box 1105, St. Louis, MO 63130 (United States)

2013-10-10T23:59:59.000Z

396

Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma  

SciTech Connect (OSTI)

Neutralization and focusing of intense charged particle beam pulses by a background plasma forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating through the background plasma. If controlled, this physical effect can be used for optimized beam transport over long distances.

Kaganovich, I.D.; Davidson, R.C.; Dorf, M.A.; Startsev, E.A.; Sefkow, A.B; Friedman, A.F.; Lee, E.P.

2009-09-03T23:59:59.000Z

397

A New Robust Operator for Computer Vision: Application to Range and Intensity Images  

E-Print Network [OSTI]

because both the foreground and background project to the same sensor pixel, and in part because along on the robustness of reconstruction techniques. First, when there are many depth discontinuities, range sensors can in the foreground and one in the background, intermingling over large image regions. The data values from one

Bystroff, Chris

398

Comparison of estimated and background subsidence rates in Texas-Louisiana geopressured geothermal areas  

SciTech Connect (OSTI)

A comparison of background and potential geopressured geothermal development-related subsidence rates is given. Estimated potential geopressured-related rates at six prospects are presented. The effect of subsidence on the Texas-Louisiana Gulf Coast is examined including the various associated ground movements and the possible effects of these ground movements on surficial processes. The relationships between ecosystems and subsidence, including the capability of geologic and biologic systems to adapt to subsidence, are analyzed. The actual potential for environmental impact caused by potential geopressured-related subsidence at each of four prospects is addressed. (MHR)

Lee, L.M.; Clayton, M.; Everingham, J.; Harding, R.C.; Massa, A.

1982-06-01T23:59:59.000Z

399

Background Information for the Nevada National Security Site Integrated Sampling Plan, Revision 0  

SciTech Connect (OSTI)

This document describes the process followed to develop the Nevada National Security Site (NNSS) Integrated Sampling Plan (referred to herein as the Plan). It provides the Plans purpose and objectives, and briefly describes the Underground Test Area (UGTA) Activity, including the conceptual model and regulatory requirements as they pertain to groundwater sampling. Background information on other NNSS groundwater monitoring programsthe Routine Radiological Environmental Monitoring Plan (RREMP) and Community Environmental Monitoring Program (CEMP)and their integration with the Plan are presented. Descriptions of the evaluations, comments, and responses of two Sampling Plan topical committees are also included.

Farnham, Irene; Marutzky, Sam

2014-12-01T23:59:59.000Z

400

Early Standard Model Measurement and Determination of Standard Model Background for Searches  

E-Print Network [OSTI]

The Large Hadron Collider (LHC) at CERN in Geneva (Switzerland) will go in operation in the coming months and will soon enable us to analyze the highest energy collisions ever produced at an accelerator. Beyond Standard Model searches at LHC require a detailed understanding of the detector performance, reconstruction algorithms and triggering. Precision measurements of Standard Model processes are also mandatory to acquire the necessary knowledge of Standard Model background. Both ATLAS and CMS efforts are hence addressed to determine the best calibration candles and to design a realistic plan for the initial period of data taking.

S. Beauceron

2008-08-27T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

The Cosmic MeV Neutrino Background as a Laboratory for Black Hole Formation  

E-Print Network [OSTI]

Calculations of the cosmic rate of core collapses, and the associated neutrino flux, commonly assume that a fixed fraction of massive stars collapse to black holes. We argue that recent results suggest that this fraction instead increases with redshift. With relatively more stars vanishing as "unnovae" in the distant universe, the detectability of the cosmic MeV neutrino background is improved due to their hotter neutrino spectrum, and expectations for supernova surveys are reduced. We conclude that neutrino detectors, after the flux from normal SNe is isolated via either improved modeling or the next Galactic SN, can probe the conditions and history of black hole formation.

Hasan Yuksel; Matthew D. Kistler

2014-10-01T23:59:59.000Z

402

Cosmological Rotation of Quantum-Mechanical Origin and Anisotropy of the Microwave Background  

E-Print Network [OSTI]

It is shown that rotational cosmological perturbations can be generated in the early Universe, similarly to gravitational waves. The generating mechanism is quantum-mechanical in its nature, and the created perturbations should now be placed in squeezed vacuum quantum states. The physical conditions under which the phenomenon can occur are formulated. The generated perturbations can contribute to the large-angular-scale anisotropy of the cosmic microwave background radiation. An exact formula is derived for the angular correlation function of the temperature variations caused by the quantum-mechanically generated rotational perturbations. The multipole expansion begins from the dipole component. The comparison with the case of gravitational waves is made.

L. P. Grishchuk

1993-10-06T23:59:59.000Z

403

On the background estimation by time slides in a network of gravitational wave detectors  

E-Print Network [OSTI]

Time shifting the outputs of Gravitational Wave detectors operating in coincidence is a convenient way to estimate the background in a search for short duration signals. However this procedure is limited as increasing indefinitely the number of time shifts does not provide better estimates. We show that the false alarm rate estimation error saturates with the number of time shifts. In particular, for detectors with very different trigger rates this error saturates at a large value. Explicit computations are done for 2 detectors, and for 3 detectors where the detection statistic relies on the logical ``OR'' of the coincidences of the 3 couples in the network.

Michal Was; Marie-Anne Bizouard; Violette Brisson; Fabien Cavalier; Michel Davier; Patrice Hello; Nicolas Leroy; Florent Robinet; Vavoulidis Miltiadis

2009-11-25T23:59:59.000Z

404

Investigations of 2? decay measured by low background HPGe spectrometer OBELIX  

SciTech Connect (OSTI)

A low background high sensitive HPGe spectrometer OBELIX was installed at the Modane Underground Laboratory (LSM, France, 4800 m w.e.). The detector was designed to measure a contamination of enriched isotopes and radio-impurities in construction materials, to investigate rare nuclear processes such as resonance neutrinoless double electron capture and two-neutrino double beta decay to excited states of daughter nuclei. Spectrometer sensitivity, contamination of NEMO-3 sources and results of 2?2?{sup ?} decay of {sup 100}Mo to the 0{sup +} (1130 keV) and 2{sup +} (540 keV) excited states as well as future plans for OBELIX detector are given.

Rukhadze, Ekaterina [Institute of Experimental and Applied Physics, CTU in Prague, Horska 3a/22, 128 00 Prague 2 (Czech Republic); Collaboration: OBELIX Collaboration; SuperNEMO Collaboration

2013-12-30T23:59:59.000Z

405

Hanford Waste Vitrification Plant technical background document for best available radionuclide control technology demonstration  

SciTech Connect (OSTI)

This report provides the background documentation to support applications for approval to construct and operate new radionuclide emission sources at the Hanford Waste Vitrification Plant (HWVP) near Richland, Washington. The HWVP is required to obtain permits under federal and state statutes for atmospheric discharges of radionuclides. Since these permits must be issued prior to construction of the facility, draft permit applications are being prepared, as well as documentation to support these permits. This report addresses the applicable requirements and demonstrates that the preferred design meets energy, environmental, and economic criteria for Best Available Radionuclide Control Technology (BARCT) at HWVP. 22 refs., 11 figs., 25 tabs.

Carpenter, A.B.; Skone, S.S.; Rodenhizer, D.G.; Marusich, M.V. (Ebasco Services, Inc., Bellevue, WA (USA))

1990-10-01T23:59:59.000Z

406

Background and Derivation of ANS-5.4 Standard Fission Product Release Model  

SciTech Connect (OSTI)

This background report describes the technical basis for the newly proposed American Nuclear Society (ANS) 5.4 standard, Methods for Calculating the Fractional Release of Volatile Fission Products from Oxide Fuels. The proposed ANS 5.4 standard provides a methodology for determining the radioactive fission product releases from the fuel for use in assessing radiological consequences of postulated accidents that do not involve abrupt power transients. When coupled with isotopic yields, this method establishes the 'gap activity,' which is the inventory of volatile fission products that are released from the fuel rod if the cladding are breached.

Beyer, Carl E.; Turnbull, Andrew J.

2010-01-29T23:59:59.000Z

407

CUORE crystal validation runs: results on radioactive contamination and extrapolation to CUORE background  

E-Print Network [OSTI]

The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performances and the radiopurity of the TeO$_2$ crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.

Alessandria, F; Ardito, R; Arnaboldi, C; Avignone, F T; Balata, M; Bandac, I; Banks, T I; Bari, G; Beeman, J W; Bellini, F; Bersani, A; Biassoni, M; Bloxham, T; Brofferio, C; Bryant, A; Bucci, C; Cai, X Z; Canonica, L; Capelli, S; Carbone, L; Cardani, L; Carrettoni, M; Chott, N; Clemenza, M; Cosmelli, C; Cremonesi, O; Creswick, R J; Dafinei, I; Dally, A; De Biasi, A; Decowski, M P; Deninno, M M; de Waard, A; Di Domizio, S; Ejzak, L; Faccini, R; Fang, D Q; Farach, H; Ferri, E; Ferroni, F; Fiorini, E; Foggetta, L; Freedman, S; Frossati, G; Giachero, A; Gironi, L; Giuliani, A; Gorla, P; Gotti, C; Guardincerri, E; Gutierrez, T D; Haller, E E; Han, K; Heeger, K M; Huang, H Z; Ichimura, K; Kadel, R; Kazkaz, K; Keppel, G; Kogler, L; Kolomensky, Y G; Kraft, S; Lenz, D; Li, Y L; Liu, X; Longo, E; Ma, Y G; Maiano, C; Maier, G; Martinez, C; Martinez, M; Maruyama, R H; Moggi, N; Morganti, S; Newman, S; Nisi, S; Nones, C; Norman, E B; Nucciotti, A; Orio, F; Orlandi, D; Ouellet, J; Pallavicini, M; Palmieri, V; Pattavina, L; Pavan, M; Pedretti, M; Pessina, G; Pirro, S; Previtali, E; Rampazzo, V; Rimondi, F; Rosenfeld, C; Rusconi, C; Salvioni, C; Sangiorgio, S; Schaeffer, D; Scielzo, N D; Sisti, M; Smith, A R; Stivanello, F; Taffarello, L; Terenziani, G; Tian, W D; Tomei, C; Trentalange, S; Ventura, G; Vignati, M; Wang, B; Wang, H W; Whitten, C A; Wise, T; Woodcraft, A; Xu, N; Zanotti, L; Zarra, C; Zhu, B X; Zucchelli, S

2011-01-01T23:59:59.000Z

408

CUORE crystal validation runs: results on radioactive contamination and extrapolation to CUORE background  

E-Print Network [OSTI]

The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performances and the radiopurity of the TeO$_2$ crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.

F. Alessandria; E. Andreotti; R. Ardito; C. Arnaboldi; F. T. Avignone III; M. Balata; I. Bandac; T. I. Banks; G. Bari; J. W. Beeman; F. Bellini; A. Bersani; M. Biassoni; T. Bloxham; C. Brofferio; A. Bryant; C. Bucci; X. Z. Cai; L. Canonica; S. Capelli; L. Carbone; L. Cardani; M. Carrettoni; N. Chott; M. Clemenza; C. Cosmelli; O. Cremonesi; R. J. Creswick; I. Dafinei; A. Dally; A. De Biasi; M. P. Decowski; M. M. Deninno; A. de Waard; S. Di Domizio; L. Ejzak; R. Faccini; D. Q. Fang; H. Farach; E. Ferri; F. Ferroni; E. Fiorini; L. Foggetta; S. Freedman; G. Frossati; A. Giachero; L. Gironi; A. Giuliani; P. Gorla; C. Gotti; E. Guardincerri; T. D. Gutierrez; E. E. Haller; K. Han; K. M. Heeger; H. Z. Huang; K. Ichimura; R. Kadel; K. Kazkaz; G. Keppel; L. Kogler; Y. G. Kolomensky; S. Kraft; D. Lenz; Y. L. Li; X. Liu; E. Longo; Y. G. Ma; C. Maiano; G. Maier; C. Martinez; M. Martinez; R. H. Maruyama; N. Moggi; S. Morganti; S. Newman; S. Nisi; C. Nones; E. B. Norman; A. Nucciotti; F. Orio; D. Orlandi; J. Ouellet; M. Pallavicini; V. Palmieri; L. Pattavina; M. Pavan; M. Pedretti; G. Pessina; S. Pirro; E. Previtali; V. Rampazzo; F. Rimondi; C. Rosenfeld; C. Rusconi; C. Salvioni; S. Sangiorgio; D. Schaeffer; N. D. Scielzo; M. Sisti; A. R. Smith; F. Stivanello; L. Taffarello; G. Terenziani; W. D. Tian; C. Tomei; S. Trentalange; G. Ventura; M. Vignati; B. Wang; H. W. Wang; C. A. Whitten Jr; T. Wise; A. Woodcraft; N. Xu; L. Zanotti; C. Zarra; B. X. Zhu; S. Zucchelli

2011-09-05T23:59:59.000Z

409

Wave breaking phenomenon of lower-hybrid oscillations induced by a background inhomogeneous magnetic field  

SciTech Connect (OSTI)

In a fluid description, we study space-time evolution of lower hybrid modes in a cold quasi-neutral homogeneous plasma in presence of a background inhomogeneous magnetic field. Within a linear analysis, a dispersion relation with inhomogeneous magnetic field shows 'phase mixing' of such oscillations. A manifestation of 'phase mixing' is shown in 'mode coupling.' By using Lagrangian variables, an exact solution is presented in parametric form of this nonlinear time dependent problem. It is demonstrated that initially excited lower hybrid modes always break via phase mixing phenomenon in presence of an inhomogeneous magnetic field. Breaking of such oscillations is revealed by the appearance of spikes in the plasma density profile.

Maity, Chandan; Chakrabarti, Nikhil [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Sengupta, Sudip [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2012-10-15T23:59:59.000Z

410

Background p(450 GeV/c)-p,d (NA51)  

E-Print Network [OSTI]

#12;#12;Background ' Open charm J / Drell-Yan #12;* p(450 GeV/c)-p,d (NA51) 208 16 p(200 Ge) 32 p(450 GeV/c)-A (A=C,Al,Cu,W) (NA38) 10101 10101010 652 3 4 B targetprojectile B(J/)/(AB)(nb) 5 4 3 Pb(208x158 GeV/c)-Pb (NA50) S(32x200 GeV/c)-U (NA38) p(200 GeV/c)-W (NA38) p(450 GeV/c)-A (A=p,d) (NA

Paris-Sud XI, Universit de

411

US--EC fuel cycle study: Background document to the approach and issues  

SciTech Connect (OSTI)

In February 1991, DOE and the Commission of the European Communities (EC), signed a joint statement regarding the external costs of fuel cycles. This 18-month agreement committed their respective organizations to ``develop a comparative analytical methodology and to develop the best range of estimates of external costs from secondary sources`` for eight fuel cycles and four conservation options. In our study, a fuel cycle is defined as the series of physical and chemical processes and activities that are required to generate electricity from a specific fuel or resource. This foundation phase of the study is primarily limited to developing and demonstrating methods for estimating impacts and their monetized value, what we term ``damages`` or ``benefits,`` leaving aside the extent to which such damages have been internalized. However, Appendix C provides the conceptual framework for evaluating the extent of internalization. This report is a background document to introduce the study approach and to discuss the major conceptual and practical issues entailed by the incremental damage problem. As a background document, the report seeks to communicate an overview of the study and the important methodological choices that were made to conduct the research. In successive sections of the report, the methodological tools used in the study are discussed; the ecological and health impacts are reviewed using the coal fuel cycle as a reference case; and, in the final chapter, the methods for valuing impacts are detailed.

Not Available

1992-11-01T23:59:59.000Z

412

US--EC fuel cycle study: Background document to the approach and issues  

SciTech Connect (OSTI)

In February 1991, DOE and the Commission of the European Communities (EC), signed a joint statement regarding the external costs of fuel cycles. This 18-month agreement committed their respective organizations to develop a comparative analytical methodology and to develop the best range of estimates of external costs from secondary sources'' for eight fuel cycles and four conservation options. In our study, a fuel cycle is defined as the series of physical and chemical processes and activities that are required to generate electricity from a specific fuel or resource. This foundation phase of the study is primarily limited to developing and demonstrating methods for estimating impacts and their monetized value, what we term damages'' or benefits,'' leaving aside the extent to which such damages have been internalized. However, Appendix C provides the conceptual framework for evaluating the extent of internalization. This report is a background document to introduce the study approach and to discuss the major conceptual and practical issues entailed by the incremental damage problem. As a background document, the report seeks to communicate an overview of the study and the important methodological choices that were made to conduct the research. In successive sections of the report, the methodological tools used in the study are discussed; the ecological and health impacts are reviewed using the coal fuel cycle as a reference case; and, in the final chapter, the methods for valuing impacts are detailed.

Not Available

1992-11-01T23:59:59.000Z

413

Neutrino Physics from the Cosmic Microwave Background and Large Scale Structure  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

This is a report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for the Cosmic Frontier of the Division of Particles and Fields Community Summer Study long-term planning exercise. Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure. The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve ? (?mv) = 16 meV and ? (Neff)(Neff) = 0.020. Such a mass measurement will produce a high significance detection of non-zero ?m??m?, whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV. If neutrinos have a minimal normal mass hierarchy, this measurement will definitively rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the Standard Model of particle physics the origin of mass. This precise a measurement of Neff will allow for high sensitivity to any light and dark degrees of freedom produced in the big bang and a precision test of the standard cosmological model prediction that Neff = 3.046.

Slosar, A.; Arnold, K.; Austermann, J.; Benson, B. A.; Bischoff, C.; Bock, J.; Bond, J. R.; Borrill, J.; Calabrese, E.; Carlstrom, J. E.; Carvalho, C. S.; Chang, C. L.; Chiang, H. C.; Church, S.; Cooray, A.; Crawford, T. M.; Dawson, K. S.; Das, S.; Devlin, M. J.; Dobbs, M.; Dodelson, S.; Dore, O.; Dunkley, J.; Errard, J.; Fraisse, A.; Gallicchio, J.; Halverson, N. W.; Hanany, S.; Hildebrandt, S. R.; Hincks, A.; Hlozek, R.; Holder, G.; Holzapfel, W. L.; Honscheid, K.; Hu, W.; Hubmayr, J.; Irwin, K.; Jones, W. C.; Kamionkowski, M.; Keating, B.; Keisler, R.; Knox, L.; Komatsu, E.; Kovac, J.; Lawrence, C.; Lee, A. T.; Leitch, E.; Linder, E.; Lubin, P.; McMahon, J.; Miller, A.; Newburgh, L.; Niemack, M. D.; Nguyen, H.; Nguyen, H. T.; Page, L.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Sehgal, N.; Seljak, U.; Sievers, J.; Silverstein, E.; Smith, K. M.; Spergel, D.; Staggs, S. T.; Stark, A.; Stompor, R.; Vieregg, A. G.; Wang, G.; Watson, S.; Wollack, E. J.; Wu, W. L.K.; Yoon, K. W.; Zahn, O.; Kuo, C. -L.

2015-03-01T23:59:59.000Z

414

The Hawking Temperature in the context of Dark Energy for Reissner-Nordstrom and Kerr background  

E-Print Network [OSTI]

For emergent gravity metrics, presence of dark energy modifies the Hawking temperature. We show that for the spherically symmetric Reissner-Nordstrom (RN) background metric, the emergent metric can be mapped into a Robinson-Trautman blackhole. Allowed values of the dark energy density follow from rather general conditions. For some allowed value of the dark energy density this blackhole can have zero Hawking temperature i.e. the blackhole does not radiate. For a Kerr background along $\\theta=0$, the emergent blackhole metric satisfies Einstein's equations for large $r$ and always radiates. Our analysis is done in the context of emergent gravity metrics having $k-$essence scalar fields $\\phi$ with a Born-Infeld type lagrangian. In both cases the scalar field $\\phi(r,t)=\\phi_{1}(r)+\\phi_{2}(t)$ also satisfies the emergent gravity equations of motion for $r\\rightarrow\\infty$ and $\\theta=0$. \\keywords{dark energy, k-essence, Reissner-Nordstrom and Kerr blackholes} \\pacs{98.80.-k ;95.36.+x}

Goutam Manna; Debashis Gangopadhyay

2014-03-17T23:59:59.000Z

415

An array of low-background 3He proportional counters for theSudbury Neutrino Observatory  

SciTech Connect (OSTI)

An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neutrons liberated by the neutrino-deuteronneutral current reaction in the D2O, and four strings lled with a mixtureof 4He and CF4 gas for background measurements. The proportional counterdiameter is 5 cm. The total deployed array length was 398 m. The SNO NCDarray is the lowest-radioactivity large array of proportional countersever produced. This article describes the design, construction,deployment, and characterization of the NCD array, discusses theelectronics and data acquisition system, and considers event signaturesand backgrounds.

Amsbaugh, J.F.; Anaya, J.M.; Banar, J.; Bowles, T.J.; Browne,M.C.; Bullard, T.V.; Burritt, T.H.; Cox-Mobrand, G.A.; Dai, X.; H.Deng,X.; Di Marco, M.; Doe, P.J.; Dragowsky, M.R.; Duba, C.A.; Duncan, F.A.; Earle, E.D.; Elliott, S.R.; Esch, E.-I.; Fergani, H.; Formaggio, J.A.; Fowler, M.M.; Franklin, J.E.; Geissbuehler, P.; Germani, J.V.; Goldschmidt, A.; Guillian, E.; Hallin, A.L.; Harper, G.; Harvey, P.J.; Hazama, R.; Heeger, K.M.; Heise, J.; Hime, A.; Howe, M.A.; Huang, M.; Kormos, L.L.; Kraus, C.; Krauss, C.B.; Law, J.; Lawson, I.T.; Lesko,K.T.; Loach, J.C.; Majerus, S.; Manor, J.; McGee, S.; Miknaitis, K.K.S.; Miller, G.G.; Morissette, B.; Myers, A.; Oblath, N.S.; O'Kee, H.M.; Ollerhead, R.W.; Peeters, S.J.M.; Poon, A.W.P.; Prior, G.; Reitzner,S.D.; Rielage, K.; Robertson, R.G.H.; Skensved, P.; Smith, A.R.; Smith,M.W.E.; Steiger, T.D.; Stonehill,L.C.; Thornewell, P.M.; Tolich, N.; VanDevender, B.A.; VanWechel, T.D.; Wall, B.L.; Tseung, H.W.C.; Wendland,J.; West, N.; Wilhelmy, J.B.; Wilkerson, J.F.; Wouters, J.M.

2007-02-01T23:59:59.000Z

416

Reduction of Radioactive Backgrounds in Electroformed Copper for Ultra-Sensitive Radiation Detectors  

SciTech Connect (OSTI)

Abstract Ultra-pure construction materials are required for the next generation of neutrino physics, dark matter and environmental science applications. These new efforts require materials with purity levels at or below 1 uBq/kg 232Th and 238U. Yet radiometric analysis lacks sensitivity below ~10 uBq/kg for the U and Th decay chains. This limits both the selection of clean materials and the validation of purification processes. Copper is an important high-purity material for low-background experiments due to the ease with which it can be purified by electrochemical methods. Electroplating for purification into near-final shapes, known as electroforming, is one such method. Continued refinement of the copper electroforming process is underway, for the first time guided by an ICP-MS based assay method that can measure 232Th and 238U near the desired purity levels. An assay of electroformed copper at 10 uBq/kg for 232Th has been achieved and is described. The implications of electroformed copper at or better than this purity on next-generation low-background experiments are discussed.

Hoppe, Eric W.; Aalseth, Craig E.; Farmer, Orville T.; Hossbach, Todd W.; Liezers, Martin; Miley, Harry S.; Overman, Nicole R.; Reeves, James H.

2014-02-08T23:59:59.000Z

417

State background-radiation levels: results of measurements taken during 1975-1979  

SciTech Connect (OSTI)

Background radiation levels across the United States have been measured by the Off-Site Pollutant Measurements Group of the Health and Safety Research Division at Oak Ridge National Laboratory (ORNL). These measurements have been conducted as part of the ORNL program of radiological surveillance at inactive uranium mills and sites formerly utilized during Manhattan Engineer District and early Atomic Energy Commission projects. The measurements included determination of /sup 226/Ra, /sup 232/Th, and /sup 238/U concentrations in surface soil samples and measurement of external gamma-ray exposure rates at 1 m above the ground surface at the location of soil sampling. This information is being utilized for comparative purposes to determine the extent of contamination present at the survey sites and surrounding off-site areas. The sampling program to date has provided background information at 356 locations in 33 states. External gamma-ray exposure rates were found to range from less than 1 to 34 ..mu..R/h, with an US average of 8.5 ..mu..R/h. The nationwide average concentrations of /sup 226/Ra, /sup 232/Th, and /sup 238/U in surface soil were determined to be 1.1, 0.98, and 1.0 pCi/g, respectively.

Myrick, T.E.; Berven, B.A.; Haywood, F.F.

1981-11-01T23:59:59.000Z

418

Long-term study of backgrounds in the DRIFT-II directional dark matter experiment  

E-Print Network [OSTI]

Low-pressure gas Time Projection Chambers being developed for directional dark matter searches offer a technology with strong particle identification capability combined with the potential to produce a definitive detection of Galactic Weakly Interacting Massive Particle (WIMP) dark matter. A source of events able to mimic genuine WIMP-induced nuclear recoil tracks arises in such experiments from the decay of radon gas inside the vacuum vessel. The recoils that result from associated daughter nuclei are termed Radon Progeny Recoils (RPRs). We present here experimental data from a long-term study using the DRIFT-II directional dark matter experiment at the Boulby Underground Laboratory of the RPRs, and other backgrounds that are revealed by relaxing the normal cuts that are applied to WIMP search data. By detailed examination of event classes in both spatial and time coordinates using 5.5 years of data, we demonstrate the ability to determine the origin of 4 specific background populations and describe development of new technology and mitigation strategies to suppress them.

J. Brack; E. Daw; A. Dorofeev; A. C. Ezeribe; J. R. Fox; J. -L. Gauvreau; M. Gold; L. J. Harmon; J. Harton; R. Lafler; J. M. Landers; R. Lauer; E. R. Lee; D. Loomba; J. A. J. Matthews; E. H. Miller; A. Monte; A. StJ. Murphy; S. M. Paling; N. Phan; M. Pipe; M. Robinson; S. Sadler; A. Scarff; D. P. Snowden-Ifft; N. J. C. Spooner; S. Telfer; D. Walker; L. Yuriev

2014-05-12T23:59:59.000Z

419

A Polarization Sensitive Bolometric Detector for Observations of the Cosmic Microwave Background  

E-Print Network [OSTI]

We have developed a bolometric detector that is intrinsically sensitive to linear polarization which is optimized for making measurements of the polarization of the cosmic microwave background radiation. The receiver consists of a pair of co-located silicon nitride micromesh absorbers which couple anisotropically to linearly polarized radiation through a corrugated waveguide structure. This system allows simultaneous background limited measurements of the Stokes I and Q parameters over ~ 30% bandwidths at frequencies from ~ 60 to 600 GHz. Since both linear polarizations traverse identical optical paths from the sky to the point of detection, the susceptibility to systematic effects is minimized. The amount of uncorrelated noise between the two polarization senses is limited to the quantum limit of thermal and photon shot noise, while drifts in the relative responsivity to orthogonal polarizations are limited to the effect of non-uniformity in the thin film deposition of the leads and the intrinsic thermistor properties. Devices using NTD Ge thermistors have achieved NEPs of 2 x 10^{-17} W/sqrt{Hz} with a 1/f knee below 100 mHz at a base temperature of 270 mK. Numerical modelling of the structures has been used to optimize the bolometer geometry and coupling to optics. Comparisons of numerical results and experimental data are made. A description of how the quantities measured by the device can be interpreted in terms of the Stokes parameters is presented. The receiver developed for the Boomerang and Planck HFI focal planes is presented in detail.

W. C. Jones; R. S. Bhatia; J. J. Bock; A. E. Lange

2002-09-08T23:59:59.000Z

420

The Origin of the Extragalactic Gamma-Ray Background and Implications for Dark-Matter Annihilation  

E-Print Network [OSTI]

The origin of the extragalactic $\\gamma$-ray background (EGB) has been debated for some time. { The EGB comprises the $\\gamma$-ray emission from resolved and unresolved extragalactic sources, such as blazars, star-forming galaxies and radio galaxies, as well as radiation from truly diffuse processes.} This letter focuses on the blazar source class, the most numerous detected population, and presents an updated luminosity function and spectral energy distribution model consistent with the blazar observations performed by the {\\it Fermi} Large Area Telescope (LAT). We show that blazars account for 50$^{+12}_{-11}$\\,\\% of the EGB photons ($>$0.1\\,GeV), and that {\\it Fermi}-LAT has already resolved $\\sim$70\\,\\% of this contribution. Blazars, and in particular low-luminosity hard-spectrum nearby sources like BL Lacs, are responsible for most of the EGB emission above 100\\,GeV. We find that the extragalactic background light, which attenuates blazars' high-energy emission, is responsible for the high-energy cut-off...

Ajello, M; Sanchez-Conde, M; Zaharijas, G; Gustafsson, M; Cohen-Tanugi, J; Dermer, C D; Inoue, Y; Hartmann, D; Ackermann, M; Bechtol, K; Franckowiak, A; Reimer, A; Romani, R W; Strong, A W

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

A Statistic for the Detection of Long Strings in Microwave Background Maps  

E-Print Network [OSTI]

Using analytical methods and Monte Carlo simulations, we analyze a new statistic designed to detect isolated step-like discontinuities which are coherent over large areas of Cosmic Microwave Background (CMB) pixel maps. Such coherent temperature discontinuities are predicted by the Kaiser-Stebbins effect to form due to long cosmic strings present in our present horizon. The background of the coherent step-like seed is assumed to be a scale invariant Gaussian random field which could have been produced by a superposition of seeds on smaller scales and/or by inflationary quantum fluctuations. The effects of uncorrelated Gaussian random noise are also studied. The statistical variable considered is the Sample Mean Difference (SMD) between large neighbouring sectors of CMB maps, separated by a straight line in two dimensional maps and a point in one dimensional maps. We find that including noise, the SMD statistics can detect at the $1 \\sigma$ to $2 \\sigma$ level the presense of a long string with $G\\mu (v_s \\gamma_s)= 1/(8\\pi) ((\\delta T)/T)_{rms} \\simeq 0.5 \\times 10^{-7}$ while more conventional statistics like the skewness or the kurtosis require a value of $G\\mu$ almost an order of magnitude larger for detectability at a comparable level.

Leandros Perivolaropoulos

1997-04-01T23:59:59.000Z

422

Applications of the low-background gamma spectroscopy to the geographical origin of marine salts and prunes  

E-Print Network [OSTI]

in a second one part. LOW BACKGROUND GAMMA-RAY SPECTROMETRY Most of the samples have been measured with low of two large plastic scintillators coupled to photomultipliers is installed and gives a further reduction;FIGURE 1. Schematic view of the set-up used for low background gamma spectrometry measurements

Paris-Sud XI, Universit de

423

First calculation of cosmic-ray muon spallation backgrounds for MeV astrophysical neutrino signals in Super-Kamiokande  

E-Print Network [OSTI]

When muons travel through matter, their energy losses lead to nuclear breakup ("spallation") processes. The delayed decays of unstable daughter nuclei produced by cosmic-ray muons are important backgrounds for low-energy astrophysical neutrino experiments, e.g., those seeking to detect solar neutrino or Diffuse Supernova Neutrino Background (DSNB) signals. Even though Super-Kamiokande has strong general cuts to reduce these spallation-induced backgrounds, the remaining rate before additional cuts for specific signals is much larger than the signal rates for kinetic energies of about 6 -- 18 MeV. Surprisingly, there is no published calculation of the production and properties of these backgrounds in water, though there are such studies for scintillator. Using the simulation code FLUKA and theoretical insights, we detail how muons lose energy in water, produce secondary particles, how and where these secondaries produce isotopes, and the properties of the backgrounds from their decays. We reproduce Super-Kamiokande measurements of the total background to within a factor of 2, which is good given that the isotope yields vary by orders of magnitude and that some details of the experiment are unknown to us at this level. Our results break aggregate data into component isotopes, reveal their separate production mechanisms, and preserve correlations between them. We outline how to implement more effective background rejection techniques using this information. Reducing backgrounds in solar and DSNB studies by even a factor of a few could help lead to important new discoveries.

Shirley Weishi Li; John F. Beacom

2014-04-13T23:59:59.000Z

424

Riboswitch-based sensor in low optical background Svetlana V. Harbaugh, Molly E. Davidson, Yaroslav G. Chushak*  

E-Print Network [OSTI]

Riboswitch-based sensor in low optical background Svetlana V. Harbaugh, Molly E. Davidson, Yaroslav in the presence of theophylline. However, the BFP-eGFP FRET pair posses significant optical background-4 These RNA-based sensors bind to a ligand and alter the gene expression of downstream genes. Riboswitches

425

Enhanced Self-Focusing of an Ion Beam Pulse Propagating through a Background Plasma along a Solenoidal Magnetic Field  

E-Print Network [OSTI]

Enhanced Self-Focusing of an Ion Beam Pulse Propagating through a Background Plasma along.58.Lq, 52.59.?f Neutralization and focusing of charged particle beam pulses by a background plasma form plasma elec- trons. The effects of the enhanced self-focusing are of particular importance

Kaganovich, Igor

426

COYOTE : a finite element computer program for nonlinear heat conduction problems. Part I, theoretical background.  

SciTech Connect (OSTI)

The need for the engineering analysis of systems in which the transport of thermal energy occurs primarily through a conduction process is a common situation. For all but the simplest geometries and boundary conditions, analytic solutions to heat conduction problems are unavailable, thus forcing the analyst to call upon some type of approximate numerical procedure. A wide variety of numerical packages currently exist for such applications, ranging in sophistication from the large, general purpose, commercial codes, such as COMSOL, COSMOSWorks, ABAQUS and TSS to codes written by individuals for specific problem applications. The original purpose for developing the finite element code described here, COYOTE, was to bridge the gap between the complex commercial codes and the more simplistic, individual application programs. COYOTE was designed to treat most of the standard conduction problems of interest with a user-oriented input structure and format that was easily learned and remembered. Because of its architecture, the code has also proved useful for research in numerical algorithms and development of thermal analysis capabilities. This general philosophy has been retained in the current version of the program, COYOTE, Version 5.0, though the capabilities of the code have been significantly expanded. A major change in the code is its availability on parallel computer architectures and the increase in problem complexity and size that this implies. The present document describes the theoretical and numerical background for the COYOTE program. This volume is intended as a background document for the user's manual. Potential users of COYOTE are encouraged to become familiar with the present report and the simple example analyses reported in before using the program. The theoretical and numerical background for the finite element computer program, COYOTE, is presented in detail. COYOTE is designed for the multi-dimensional analysis of nonlinear heat conduction problems. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in COYOTE are also outlined. Instructions for use of the code are documented in SAND2010-0714.

Glass, Micheal W.; Hogan, Roy E., Jr.; Gartling, David K.

2010-03-01T23:59:59.000Z

427

Schwinger Mechanism for Fermion Pair Production in the Presence of Arbitrary Time Dependent Background Electric Field  

E-Print Network [OSTI]

We study the Schwinger mechanism for the pair production of fermions in the presence of an arbitrary time-dependent background electric field E(t) by directly evaluating the path integral. We obtain an exact non-perturbative result for the probability of fermion-antifermion pair production per unit time per unit volume per unit transverse momentum (of the fermion or antifermion) from the arbitrary time dependent electric field E(t) via Schwinger mechanism. We find that the exact non-perturbative result is independent of all the time derivatives d^nE(t)/dt^n, where n=1,2,....\\infty. This result has the same functional dependence on E as the Schwinger's constant electric field E result with the replacement: E -> E(t).

Fred Cooper; Gouranga C. Nayak

2006-12-29T23:59:59.000Z

428

Coherent anti-Stokes Raman spectroscopy in the presence of strong resonant signal from background molecules  

E-Print Network [OSTI]

Optical spectroscopy with broadband femtosecond laser pulses often involves simultaneous excitation of multiple molecular species with close resonance frequencies. Interpreting the collective optical response from molecular mixtures typically requires Fourier analysis of the detected time-resolved signal. We propose an alternative method of separating coherent optical responses from two molecular species with neighboring excitation resonances (here, vibrational modes of oxygen and carbon dioxide). We utilize ro-vibrational coupling as a mechanism of suppressing the strong vibrational response from the dominating molecular species (O$_{2}$). Coherent ro-vibrational dynamics lead to long "silence windows" of zero signal from oxygen molecules. In these silence windows, the detected signal stems solely from the minority species (CO$_{2}$) enabling background-free detection and characterization of the O$_2$/CO$_2$ mixing ratio. In comparison to a Fourier analysis, our technique does not require femtosecond time resolution or time-delay scanning.

Martin Bitter; Valery Milner

2012-10-18T23:59:59.000Z

429

The Metagalactic Ionizing Background: A Crisis in UV Photon Production or Incorrect Galaxy Escape Fractions?  

E-Print Network [OSTI]

Recent suggestions of a "photon underproduction crisis" (Kollmeier et al 2014) have generated concern over the intensity and spectrum of ionizing photons in the metagalactic ultraviolet background (UVB). The balance of hydrogen photoionization and recombination determines the opacity of the low-redshift intergalactic medium (IGM). We calibrate the hydrogen photoionization rate ($\\Gamma_H$) by comparing Hubble Space Telescope spectroscopic surveys of the low-redshift column density distribution of H I absorbers to new cosmological simulations. The distribution, $f(N_{HI}, z) = d^2N/d(log N_{HI}) dz$, is consistent with an increased UVB that includes contributions from both quasars and galaxies. Our recommended fit, $\\Gamma_H(z) = (4.6x10^{-14}~s^{-1})(1+z)^{4.4}$ for $0 IV and Si III / Si IV) and suggests a 25-30\\% contribution of the...

Shull, J Michael; Danforth, Charles W; Tilton, Evan M

2015-01-01T23:59:59.000Z

430

Quenching methods for background reduction in luminescence-based probe-target binding assays  

DOE Patents [OSTI]

Background luminescence is reduced from a solution containing unbound luminescent probes, each having a first molecule that attaches to a target molecule and having an attached luminescent moiety, and luminescent probe/target adducts. Quenching capture reagent molecules are formed that are capable of forming an adduct with the unbound luminescent probes and having an attached quencher material effective to quench luminescence of the luminescent moiety. The quencher material of the capture reagent molecules is added to a solution of the luminescent probe/target adducts and binds in a proximity to the luminescent moiety of the unbound luminescent probes to quench luminescence from the luminescent moiety when the luminescent moiety is exposed to exciting illumination. The quencher capture reagent does not bind to probe molecules that are bound to target molecules and the probe/target adduct emission is not quenched.

Cai, Hong (Los Alamos, NM); Goodwin, Peter M (Los Alamos, NM); Keller, Richard A. (Los Alamos, NM); Nolan, Rhiannon L. (Santa Fe, NM)

2007-04-10T23:59:59.000Z

431

Influence of Spinning Electric Fields on Natural Background Gamma-Radiation  

E-Print Network [OSTI]

This paper considers influence of spinning electric field on statistics of natural background gamma-radiation. The spinning electric field, shown as a virtual gyroscope, has quantum mechanics characteristics. Interaction of the virtual fermion-like gyroscope with bosons (gamma-quanta) results in lowering intensity of the gamma-radiation and altering Poisson distribution. The statistic of the observed phenomenon depends on the direction of rotation of the virtual gyroscope. The results are discussed in a shade of spin-spin interaction having regard to realizing thermodynamically profitable conditions. Similarity of observed reduction of gamma-radiation in spinning electric fields and that for mechanical rotation stresses a special role of rotation itself, disregarding the matter of its carrier.

Mark Krinker; Felix Kitaichik

2010-04-28T23:59:59.000Z

432

The Second Peak: The Dark-Energy Density and the Cosmic Microwave Background  

E-Print Network [OSTI]

Supernova evidence for a negative-pressure dark energy (e.g., cosmological constant or quintessence) that contributes a fraction $\\Omega_\\Lambda\\simeq0.7$ of closure density has been bolstered by the discrepancy between the total density, $\\Omega_{\\rm tot}\\simeq1$, suggested by the location of the first peak in the cosmic microwave background (CMB) power spectrum and the nonrelativistic-matter density $\\Omega_m\\simeq0.3$ obtained from dynamical measurements. Here we show that the impending identification of the location of the {\\it second} peak in the CMB power spectrum will provide an immediate and independent probe of the dark-energy density. As an aside, we show how the measured height of the first peak probably already points toward a low matter density and places upper limits to the reionization optical depth and gravitational-wave amplitude.

Marc Kamionkowski; Ari Buchalter

2000-01-05T23:59:59.000Z

433

Interaction of a circularly polarised gravitational wave with a charged particle in a static magnetic background  

E-Print Network [OSTI]

Interaction of a charged particle in a static magnetic background, i.e., a Landau system with circularly polarised gravitational wave (GW) is studied quantum mechanically in the long wavelength and low velocity limit. We quantize the classical Hamiltonian following \\cite{speli}. The rotating polarization vectors of the circularly polarized GW are employed to form a unique directional triad which served as the coordinate axes. The Schrodinger equations for the system are cast in the form of a set of coupled linear differential equations. This system is solved by iterative technique. We compute the time-evolution of the position and momentum expectation values of the particle. The results show that the resonance behaviour obtained earlier\\cite{emgw_classical} by classical treatements of the system has a quantum analogue not only for the linearly polarized GW \\cite{emgw_1_lin}, but for circularly polarized GW as well.

Sunandan Gangopadhyay; Anirban Saha; Swarup Saha

2014-12-24T23:59:59.000Z

434

Historical Background on the Performance Assessment for the Waste Isolation Pilot Plant  

SciTech Connect (OSTI)

In 1979, six years after selecting the Delaware Basin as a potential disposal area, Congress authorized the U.S. Department of Energy to build the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, as a Research and development facility for the safe management storage, and disposal of waste contaminated with transuranic radioisotopes. In 1998, 19 years after authorization and after site selection, the U.S. Environmental Protection Agency (EPA) certified that the WIPP disposal system complied with its regulations. The EPA's decision was primarily based on the results from a performance. assessment conducted in 1996, which is summarized in this special issue of Reliability Engineering and System Safety. This performance assessment was the culmination of four preliminary performance assessments conducted between 1989 and 1992. This paper provides a historical setting and context for how the performance of the deep geologic repository at the WIPP was analyzed. Also included is background on political forces acting on the project.

RECHARD,ROBERT P.

1999-10-21T23:59:59.000Z

435

Estimation of Equivalent Sea Level Cosmic Ray Exposure for Low Background Experiment  

SciTech Connect (OSTI)

While scientists at CERN and other particle accelerators around the world explore the boundaries of high energy physics, the Majorana project investigates the other end of the spectrum with its extremely sensitive, low background, low energy detector. The MAJORANA DEMONSTRATOR aims to detect neutrinoless double beta decay (0???), a rare theoretical process in which two neutrons decay into two protons and two electrons, without the emission of the two antineutrinos that are a product of a normal double beta decay. This process is only possible if and therefore a detection would prove the neutrino is a Majorana particle, meaning that it is its own antiparticle [Aaselth et al. 2004] . The existence of such a decay would also disprove lepton conservation and give information about the neutrino's mass.

Greene, Austen T.; Orrell, John L.

2012-08-25T23:59:59.000Z

436

Massive charged scalar field in the Kerr-Newman background II: Hawking radiation  

E-Print Network [OSTI]

We perform accurate calculations of the energy-, momentum-, and charge-emission rates of a charged scalar field in the background of the Kerr-Newman black hole at the range of parameters for which the effect is not negligibly small and, at the same time, the semiclassical regime is, at least marginally, valid. For black holes with charge below or not much higher than the charge accretion limit $Q \\sim \\mu M/e$ (where $e$ and $\\mu$ are the electron's mass and charge), the time between the consequent emitting of two charged particles is very large. For primordial black holes the transition between the increasing and decreasing of the ratio $Q/M$ occurs around the charge accretion limit. The rotation increases the intensity of radiation up to three orders, while the effect of the field's mass strongly suppresses the radiation.

R. A. Konoplya; A. Zhidenko

2014-04-03T23:59:59.000Z

437

THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE NARROW-BAND SPECTROMETER  

SciTech Connect (OSTI)

We have developed a near-infrared spectrometer designed to measure the absolute intensity of the solar 854.2 nm Ca II Fraunhofer line, scattered by interplanetary dust, in the zodiacal light (ZL) spectrum. Based on the known equivalent line width in the solar spectrum, this measurement can derive the zodiacal brightness, testing models of the ZL based on morphology that are used to determine the extragalactic background light in absolute photometry measurements. The spectrometer is based on a simple high-resolution tipped filter placed in front of a compact camera with wide-field refractive optics to provide the large optical throughput and high sensitivity required for rocket-borne observations. We discuss the instrument requirements for an accurate measurement of the absolute ZL brightness, the measured laboratory characterization, and the instrument performance in flight.

Korngut, P. M.; Bock, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Renbarger, T.; Keating, B. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Arai, T.; Matsumoto, T.; Matsuura, S. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Battle, J.; Hristov, V.; Lanz, A.; Levenson, L. R.; Mason, P. [Department of Physics, California Institute of Technology, Pasadena, CA 91125 (United States); Brown, S. W.; Lykke, K. R.; Smith, A. W. [Sensor Science Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899 (United States); Cooray, A. [Center for Cosmology, University of California, Irvine, Irvine, CA 92697 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H.; Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Shultz, B., E-mail: pkorngut@caltech.edu [Materion Barr Precision Optics and Thin Film Coatings, Westford, MA 01886 (United States); and others

2013-08-15T23:59:59.000Z

438

Spectrum of the Supernova Relic Neutrino Background and Metallicity Evolution of Galaxies  

E-Print Network [OSTI]

The spectrum of the supernova relic neutrino (SRN) background from past stellar collapses including black hole formation (failed supernovae) is calculated. The redshift dependence of the black hole formation rate is considered on the basis of the metallicity evolution of galaxies. Assuming the mass and metallicity ranges of failed supernova progenitors, their contribution to SRNs is quantitatively estimated for the first time. Using this model, the dependences of SRNs on the cosmic star formation rate density, shock revival time and equation of state are investigated. The shock revival time is introduced as a parameter that should depend on the still unknown explosion mechanism of core collapse supernovae. The dependence on equation of state is considered for failed supernovae, whose collapse dynamics and neutrino emission are certainly affected. It is found that the low-energy spectrum of SRNs is mainly determined by the cosmic star formation rate density. These low-energy events will be observed in the Supe...

Nakazato, Ken'ichiro; Niino, Yuu; Suzuki, Hideyuki

2015-01-01T23:59:59.000Z

439

Shockwaves in Supernovae: New Implications on the Diffuse Supernova Neutrino Background  

E-Print Network [OSTI]

We investigate shock wave effects upon the diffuse supernova neutrino background using dynamic profiles taken from hydrodynamical simulations and calculating the neutrino evolution in three flavors with the S-matrix formalism. We show that the shock wave impact is significant and introduces modifications of the relic fluxes by about $20 \\%$ and of the associated event rates at the level of $10-20 \\%$. Such an effect is important since it is of the same order as the rate variation introduced when different oscillation scenarios (i.e. hierarchy or $\\theta_{13}$) are considered. In addition, due to the shock wave, the rates become less sensitive to collective effects, in the inverted hierarchy and when $\\sin^2 2 \\theta_{13}$ is between the Chooz limit and $10^{-5}$. We propose a simplified model to account for shock wave effects in future predictions.

Sebastien Galais; James Kneller; Cristina Volpe; Jerome Gava

2009-11-18T23:59:59.000Z

440

Late-Time Dynamics of Scalar Fields on Rotating Black Hole Backgrounds  

E-Print Network [OSTI]

Motivated by results of recent analytic studies, we present a numerical investigation of the late-time dynamics of scalar test fields on Kerr backgrounds. We pay particular attention to the issue of mixing of different multipoles and their fall-off behavior at late times. Confining ourselves to the special case of axisymmetric modes with equatorial symmetry, we show that, in agreement with the results of previous work, the late-time behavior is dominated by the lowest allowed l-multipole. However the numerical results imply that, in general, the late-time fall-off of the dominating multipole is different from that in the Schwarzschild case, and seems to be incompatible with a result of a recently published analytic study.

William Krivan

1999-07-08T23:59:59.000Z

Note: This page contains sample records for the topic "foreground background beaver" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

A New Upper Limit on the Polarization of the Cosmic Microwave Background Radiation  

E-Print Network [OSTI]

The Cosmic Microwave Background Radiation (CMB) is an invaluable probe of the conditions of the early universe. Recent measurements of its spatial anisotropy have allowed accurate determinations of several fundamental cosmological parameters, such as the curvature of the universe, the shape of the spectrum of primordial density fluctuations, and the contribution of baryons, dark matter, and dark energy to the overall energy density of the universe. In addition to being spatially non-uniform, the CMB is theorized to be slightly polarized. Measurements of this polarization, particularly at large angular scales, have the potential to provide information on primordial gravitational waves, theories of inflation, and the ionization history of the universe, as well as help further constrain cosmological parameters. Polarization has not yet been detected in the CMB. This thesis describes a recent search for CMB polarization at large angular scales, conducted in the spring of 2000 at the University of Wisconsin-Madison. After a general introduction on both CMB polarization and general microwave polarimetry, details of the experiment itself are given, as well as a full description of the data selection and analysis techniques. Using these techniques, our data lead to a new upper limit on CMB polarization at large angular scales of 10 $\\mu$K in both E- and B-type polarization at 95% confidence. If B-polarization is assumed to be zero, the limit for E-type polarization is lowered to 8 $\\mu$K. This experiment is the first of a new breed of highly-sensitive instruments that will one day map out this interesting property of the Cosmic Microwave Background Radiation.

Christopher O'Dell

2002-01-15T23:59:59.000Z

442

The Evolution of Swift/BAT blazars and the origin of the MeV background  

SciTech Connect (OSTI)

We use 3 years of data from the Swift/BAT survey to select a complete sample of X-ray blazars above 15 keV. This sample comprises 26 Flat-Spectrum Radio Quasars (FSRQs) and 12 BL Lac objects detected over a redshift range of 0.03 < z < 4.0. We use this sample to determine, for the first time in the 15-55 keV band, the evolution of blazars. We find that, contrary to the Seyfert-like AGNs detected by BAT, the population of blazars shows strong positive evolution. This evolution is comparable to the evolution of luminous optical QSOs and luminous X-ray selected AGNs. We also find evidence for an epoch-dependence of the evolution as determined previously for radio-quiet AGNs. We interpret both these findings as a strong link between accretion and jet activity. In our sample, the FSRQs evolve strongly, while our best-fit shows that BL Lacs might not evolve at all. The blazar population accounts for 10-20% (depending on the evolution of the BL Lacs) of the Cosmic X-ray background (CXB) in the 15-55 keV band. We find that FSRQs can explain the entire CXB emission for energies above 500 keV solving the mystery of the generation of the MeV background. The evolution of luminous FSRQs shows a peak in redshift (z{sub c} = 4.3 {+-} 0.5) which is larger than the one observed in QSOs and X-ray selected AGNs. We argue that FSRQs can be used as tracers of massive elliptical galaxies in the early Universe.

Ajello, M.; /SLAC /KIPAC, Menlo Park; Costamante, L.; /Stanford U., HEPL /KIPAC, Menlo Park; Sambruna, R.M.; Gehrels, N.; /NASA, Goddard; Chiang, J.; /SLAC /KIPAC, Menlo Park; Rau, A.; /Caltech; Escala, A.; /SLAC /KIPAC, Menlo Park /Cerro Calan Observ.; Greiner, J.; /Garching, Max Planck Inst., MPE; Tueller, J.; /NASA, Goddard; Wall, J.V.; /British Columbia U.; Mushotzky, R.F.; /NASA, Goddard

2009-10-17T23:59:59.000Z

443

Durability-Based Design Guide for an Automotive Structural Composite: Part 2. Background Data and Models  

SciTech Connect (OSTI)

This background report is a companion to the document entitled ''Durability-Based Design Criteria for an Automotive Structural Composite: Part 1. Design Rules'' (ORNL-6930). The rules and the supporting material characterization and modeling efforts described here are the result of a U.S. Department of Energy Advanced Automotive Materials project entitled ''Durability of Lightweight Composite Structures.'' The overall goal of the project is to develop experimentally based, durability-driven design guidelines for automotive structural composites. The project is closely coordinated with the Automotive Composites Consortium (ACC). The initial reference material addressed by the rules and this background report was chosen and supplied by ACC. The material is a structural reaction injection-molded isocyanurate (urethane), reinforced with continuous-strand, swirl-mat, E-glass fibers. This report consists of 16 position papers, each summarizing the observations and results of a key area of investigation carried out to provide the basis for the durability-based design guide. The durability issues addressed include the effects of cyclic and sustained loadings, temperature, automotive fluids, vibrations, and low-energy impacts (e.g., tool drops and roadway kickups) on deformation, strength, and stiffness. The position papers cover these durability issues. Topics include (1) tensile, compressive, shear, and flexural properties; (2) creep and creep rupture; (3) cyclic fatigue; (4) the effects of temperature, environment, and prior loadings; (5) a multiaxial strength criterion; (6) impact damage and damage tolerance design; (7) stress concentrations; (8) a damage-based predictive model for time-dependent deformations; (9) confirmatory subscale component tests; and (10) damage development and growth observations.

Corum, J.M. [ORNL; Battiste, R.L. [ORNL; Brinkman, C.R. [ORNL; Ren, W. [ORNL; Ruggles, M.B. [ORNL; Weitsman, Y.J. [ORNL; Yahr, G.T. [ORNL

1998-02-01T23:59:59.000Z

444

Heavy sterile neutrinos, entropy and relativistic energy production, and the relic neutrino background  

E-Print Network [OSTI]

We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range, with couplings to ordinary active neutrinos large enough to guarantee thermal and chemical equilibrium at epochs in the early universe with temperatures T > 1 GeV, but in a range to give decay lifetimes from seconds to minutes. Such neutrinos would decouple early, with relic densities comparable to those of photons, but decay out of equilibrium, with consequent prodigious entropy generation prior to, or during, Big Bang Nucleosynthesis (BBN). Most of the ranges of sterile neutrino rest mass and lifetime considered are at odds with Cosmic Microwave Background (CMB) limits on the relativistic particle contribution to energy density (e.g., as parameterized by N_eff). However, some sterile neutrino parameters can lead to an acceptable N_eff. These parameter ranges are accompanied by considerable dilution of the ordinary background relic neutrinos, possibly an adverse effect on BBN, but sometimes fall in a range which can explain measured neutrino masses in some particle physics models. A robust signature of these sterile neutrinos would be a measured N_eff not equal to 3 coupled with no cosmological signal for neutrino rest mass when the detection thresholds for these probes are below laboratory-established neutrino mass values, either as established by the atmospheric neutrino oscillation scale or direct measurements with, e.g., KATRIN or neutrino-less double beta decay experiments.

George M. Fuller; Chad T. Kishimoto; Alexander Kusenko

2011-10-28T23:59:59.000Z

445

The Hamiltonian formalism for scalar fields coupled to gravity in a cosmological background  

SciTech Connect (OSTI)

A novel routine to investigate the scalar fields in a cosmological context is discussed in the framework of the Hamiltonian formalism. Starting from the EinsteinHilbert action coupled to a Lagrangian density that contains two componentsone corresponding to a scalar field Lagrangian, L{sub ?}, and another that depends on the scale parameter, L{sub a}one can identify a generalized Hamiltonian density from which first-order dynamical equations can be obtained. This set up corresponds to the dynamics of FriedmannRobertsonWalker models in the presence of homogeneous fields embedded into a generalized cosmological background fluid in a system that evolves all together isentropically. Once the generalized Hamiltonian density is properly defined, the constraints on the gravitymatterfield system are straightforwardly obtained through the first-order Hamilton equations. The procedure is illustrated for three examples of cosmological interest for studies of the dark sector: real scalar fields, tachyonic fields and generalized BornInfeld tachyonic fields. The inclusion of some isentropic fluid component into the Friedmann equation allows for identifying an exact correspondence between the dark sector underlying scalar field and an ordinary real scalar field dynamics. As a final issue, the Hamiltonian formulation is used to set the first-order dynamical equations through which one obtains the exact analytical description of the cosmological evolution of a generalized Chaplygin gas (GCG) with dustlike matter, radiation or curvature contributions. Model stability in terms of the square of the sound velocity, c{sub s}{sup 2}, cosmic acceleration, q, and conditions for inflation are discussed. -- Highlights: The Hamiltonian formalism for scalar fields coupled to gravity in a cosmological background is constructed. Real scalar, tachyonic and generalized BornInfeld tachyonic-type fields are considered. An extended formulation of the HamiltonJacobi description of the dark sector dynamics driven by scalar fields is obtained.

Bernardini, A.E., E-mail: alexeb@ufscar.br; Bertolami, O., E-mail: orfeu.bertolami@fc.up.pt

2013-11-15T23:59:59.000Z

446

CORRELATIONS IN THE (SUB)MILLIMETER BACKGROUND FROM ACT Multiplication-Sign BLAST  

SciTech Connect (OSTI)

We present measurements of the auto- and cross-frequency correlation power spectra of the cosmic (sub)millimeter background at 250, 350, and 500 {mu}m (1200, 860, and 600 GHz) from observations made with the Balloon-borne Large Aperture Submillimeter Telescope (BLAST); and at 1380 and 2030 {mu}m (218 and 148 GHz) from observations made with the Atacama Cosmology Telescope (ACT). The overlapping observations cover 8.6 deg{sup 2} in an area relatively free of Galactic dust near the south ecliptic pole. The ACT bands are sensitive to radiation from the cosmic microwave background, to the Sunyaev-Zel'dovich effect from galaxy clusters, and to emission by radio and dusty star-forming galaxies (DSFGs), while the dominant contribution to the BLAST bands is from DSFGs. We confirm and extend the BLAST analysis of clustering with an independent pipeline and also detect correlations between the ACT and BLAST maps at over 25{sigma} significance, which we interpret as a detection of the DSFGs in the ACT maps. In addition to a Poisson component in the cross-frequency power spectra, we detect a clustered signal at 4{sigma}, and using a model for the DSFG evolution and number counts, we successfully fit all of our spectra with a linear clustering model and a bias that depends only on redshift and not on scale. Finally, the data are compared to, and generally agree with, phenomenological models for the DSFG population. This study demonstrates the constraining power of the cross-frequency correlation technique to constrain models for the DSFGs. Similar analyses with more data will impose tight constraints on future models.

Hajian, Amir; Battaglia, Nick; Bond, J. Richard [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Viero, Marco P.; Bock, James J. [California Institute of Technology, Pasadena, CA 91125 (United States); Addison, Graeme [Department of Astrophysics, Oxford University, Oxford, OX1 3RH (United Kingdom); Aguirre, Paula [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica, Casilla 306, Santiago 22 (Chile); Appel, John William; Duenner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hincks, Adam D. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Das, Sudeep; Dunkley, Joanna [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Devlin, Mark J.; Dicker, Simon R. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854-8019 (United States); Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Hasselfield, Matthew [Laboratoire APC, Universite Paris Diderot, 75205 Paris (France); Hilton, Matt [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of KwaZulu-Natal, Durban 4041 (South Africa); and others

2012-01-01T23:59:59.000Z

447

The Design of an Ultra-Low Background Thermosyphon for the Majorana Demonstrator  

SciTech Connect (OSTI)

The MAJORANA DEMONSTRATOR (MJD) is an ultra-low background neutrinoless double-beta decay (0???) experiment that will deploy up to 40 kg of high purity germanium detectors (HPGe). The goal of this experiment is to demonstrate the feasibility of building a detector array with less than 1 event/ton-year in a 4 keV region of interest around the 0??? signal. HPGe diodes, when used as ionizing radiation detectors, need to be maintained at a temperature close to that of liquid nitrogen (77 K). This work describes the R&D results of a cryogenic system capable of meeting the requirements of low background and the cooling capacity required to successfully operate such a detector system. The MJD germanium detector modules will operate at liquid nitrogen temperature to provide adequate cooling for a full range of HPGe impurity concentrations. This paper shows the experimental results obtained using a two-phase horizontal thermosyphon using liquid nitrogen as the MJDs cooling system. The cold test shows that the proposed thermosyphon has sufficient cooling power to handle the heat load of an MJD module. Results for the temperature gradient across the thermosyphon, cooling capacity, and design considerations demonstrate that the thermosyphon can effectively remove the calculated heat load of each module of the experiment. The thermosyphon will be bolted to a cold plate from which detector strings will hang. The thermal conductivity of a mockup of the MJD bolted thermal joint is experimentally determined to be below 0.1 K/W.

Aguayo Navarrete, Estanislao; Busch, Matthew; Daniels, Randy; Fast, James E.; Green, Matthew P.; Reid, Douglas J.

2013-05-01T23:59:59.000Z

448

The Cryogenic Dark Matter Search and Background Rejection with Event Position Information  

SciTech Connect (OSTI)

Evidence from observational cosmology and astrophysics indicates that about one third of the universe is matter, but that the known baryonic matter only contributes to the universe at 4%. A large fraction of the universe is cold and non-baryonic matter, which has important role in the universe structure formation and its evolution. The leading candidate for the non-baryonic dark matter is Weakly Interacting Massive Particles (WIMPs), which naturally occurs in the supersymmetry theory in particle physics. The Cryogenic Dark Matter Search (CDMS) experiment is searching for evidence of a WIMP interaction off an atomic nucleus in crystals of Ge and Si by measuring simultaneously the phonon energy and ionization energy of the interaction in the CDMS detectors. The WIMP interaction energy is from a few keV to tens of keV with a rate less than 0.1 events/kg/day. To reach the goal of WIMP detection, the CDMS experiment has been conducted in the Soudan mine with an active muon veto and multistage passive background shields. The CDMS detectors have a low energy threshold and background rejection capabilities based on ionization yield. However, betas from contamination and other radioactive sources produce surface interactions, which have low ionization yield, comparable to that of bulk nuclear interactions. The low-ionization surface electron recoils must be removed in the WIMP search data analysis. An emphasis of this thesis is on developing the method of the surface-interaction rejection using location information of the interactions, phonon energy distributions and phonon timing parameters. The result of the CDMS Soudan run118 92.3 live day WIMP search data analysis is presented, and represents the most sensitive search yet performed.

Wang, Gen-sheng

2005-01-01T23:59:59.000Z

449

Digital Pulse-Shape Discrimination Applied to an Ultra-Low-Background Gas-Proportional Counting System: First Results  

SciTech Connect (OSTI)

Abstract A new ultra-low-background proportional counter (ULBPC) design was recently developed at Pacific Northwest National Laboratory (PNNL). This design, along with an ultra-low-background counting system (ULBCS) which provides passive and active shielding with radon exclusion, has been developed to complement a new shallow underground laboratory (~30 meters water-equivalent) constructed at PNNL. After these steps to mitigate dominant backgrounds (cosmic rays, external gamma-rays, radioactivity in materials), remaining background events do not exclusively arise from ionization of the proportional counter gas. Digital pulse-shape discrimination (PSD) is thus employed to further improve measurement sensitivity. In this work, a template shape is generated for each individual sample measurement of interest, a "self-calibrating" template. Differences in event topology can also cause differences in pulse shape. In this work, the temporal region analyzed for each event is refined to maximize background discrimination while avoiding unwanted sensitivity to event topology. This digital PSD method is applied to sample and background data, and initial measurement results from a biofuel methane sample are presented in the context of low-background measurements currently being developed.

Aalseth, Craig E.; Day, Anthony R.; Fuller, Erin S.; Hoppe, Eric W.; Keillor, Martin E.; Mace, Emily K.; Myers, A. W.; Overman, Cory T.; Panisko, Mark E.; Seifert, Allen; Warren, Glen A.; Williams, Richard M.

2013-05-01T23:59:59.000Z

450

Measurement of low radioactivity background in a high voltage cable by high resolution inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

The measurement of naturally occurring low level radioactivity background in a high voltage (HV) cable by high resolution inductively coupled plasma mass spectrometry (HR ICP MS) is presented in this work. The measurements were performed at the Chemistry Service of the Gran Sasso National Laboratory. The contributions to the radioactive background coming from the different components of the heterogeneous material were separated. Based on the mass fraction of the cable, the whole contamination was calculated. The HR ICP MS results were cross-checked by gamma ray spectroscopy analysis that was performed at the low background facility STELLA (Sub Terranean Low Level Assay) of the LNGS underground lab using HPGe detectors.

Vacri, M. L. di; Nisi, S.; Balata, M. [Gran Sasso National Laboratory, Chemistry Service, SS 17bis km 18.910, 67100 Assergi (Aq) (Italy)] [Gran Sasso National Laboratory, Chemistry Service, SS 17bis km 18.910, 67100 Assergi (Aq) (Italy)

2013-08-08T23:59:59.000Z

451

Integrated Molecular Analysis Indicates Undetectable Change in DNA Damage in Mice after Continuous Irradiation at ~ 400-fold Natural Background Radiation  

E-Print Network [OSTI]

Background: In the event of a nuclear accident, people are exposed to elevated levels of continuous low dose-rate radiation. Nevertheless, most of the literature describes the biological effects of acute radiation.

Olipitz, Werner

452

SURFACE GEOPHYSICAL EXPLORATION OF SX TANK FARM AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH MAGNETICS AND ELECTROMAGNETICS  

SciTech Connect (OSTI)

This report presents the results of the background characterization of the cribs and trenches surrounding the SX tank farm prepared by HydroGEOPHYSICS Inc, Columbia Energy & Environmental Services Inc and Washington River Protection Solutions.

MYERS DA; RUCKER D; LEVIT M; CUBBAGE B; HENDERSON C

2009-09-24T23:59:59.000Z

453

Background and Scattered Light Subtraction in the High-Resolution Echelle Modes of the Space Telescope Imaging Spectrograph  

E-Print Network [OSTI]

We present a simple, effective approach for estimating the on-order backgrounds of spectra taken with the highest-resolution modes of the Space Telescope Imaging Spectrograph (STIS) on-board the Hubble Space Telescope. Our scheme for determining the on-order background spectrum uses polynomial fits to the inter-order scattered light visible in the two-dimensional STIS MAMA images. We present a suite of high-resolution STIS spectra to demonstrate that our background subtraction routine produces the correct overall zero point, as judged by the small residual flux levels in the centers of strongly-saturated interstellar absorption lines. Although there are multiple sources of background light in STIS echelle mode data, this simple approach works very well for wavelengths longward of Lyman-alpha. At shorter wavelengths, the smaller order separation and generally lower signal-to-noise ratios of the data can reduce the effectiveness of our background estimation procedure. Slight artifacts in the background-subtracted spectrum can be seen in some cases, particularly at wavelengths <1300 Ang. Most of these are caused by echelle scattering of strong spectral features into the inter-order light. We discuss the limitations of high-resolution STIS data in light of the uncertainties associated with our background subtraction procedure. We compare our background-subtracted STIS spectra with GHRS Ech-A observations of the DA white dwarf G191-B2B and GHRS first-order G160M observations of the early-type star HD 218915. We find no significant differences between the GHRS data and the STIS data reduced with our method in either case.

J. Christopher Howk; Kenneth R. Sembach

1999-12-17T23:59:59.000Z

454

Final Technical Report [Cosmogenic background and shielding R&D for a Ge Neutrinoless Double Beta Decay Experiment  

SciTech Connect (OSTI)

The USD Majorana group focused all of its effort in support of the MAJORANA DEMONSTRATOR (MJD) experiment. Final designs of the shielding subsystems are complete. Construction of the MJD shielding systems at SURF has begun and the proposed activities directly support the completion of the shield systems. The PI and the group contribute heavily to the onsite construction activities of the MJD experiment. The group led investigations into neutron and neutron-?induced backgrounds, shielding effectiveness and design, and radon backgrounds.

Guiseppe, Vince

2013-10-01T23:59:59.000Z

455

Final report on the Background Soil Characterization Project at the Oak Ridge Reservation, Oak Ridge, Tennessee. Volume 3: Project Plan  

SciTech Connect (OSTI)

The Background Soil Characterization Project (BSCP) will provide background concentration levels of selected metals, organic compounds, and radionuclides in soils from uncontaminated on-site areas at the Oak Ridge Reservation (ORR), and off-site in the western part of Roane County and the eastern part of Anderson County. The BSCP will establish a database, recommend how to use the data for contaminated site assessment, and provide estimates of the potential human health and environmental risks associated with the background level concentrations of potentially hazardous constituents. ORR background soil characterization data will be used for two purposes. The first application will be in differentiating between naturally occurring constituents and site-related contamination. This is a very important step in a risk assessment because if sufficient background data are not available, no constituent known to be a contaminant can be eliminated from the assessment even if the sampled concentration is measured at a minimum level. The second use of the background data will be in calculating baseline risks against which site-specific contamination risks can be compared.

Hatmaker, T.L.; Hook, L.A.; Jackson, B.L. [and others

1993-10-01T23:59:59.000Z

456

Terracentric Nuclear Fission Reactor: Background, Basis, Feasibility, Structure, Evidence, and Geophysical Implications  

E-Print Network [OSTI]

The background, basis, feasibility, structure, evidence, and geophysical implications of a naturally occurring Terracentric nuclear fission georeactor are reviewed. For a nuclear fission reactor to exist at the center of the Earth, all of the following conditions must be met: (1) There must originally have been a substantial quantity of uranium within Earth's core; (2) There must be a natural mechanism for concentrating the uranium; (3) The isotopic composition of the uranium at the onset of fission must be appropriate to sustain a nuclear fission chain reaction; (4) The reactor must be able to breed a sufficient quantity of fissile nuclides to permit operation over the lifetime of Earth to the present; (5) There must be a natural mechanism for the removal of fission products; (6) There must be a natural mechanism for removing heat from the reactor; (7) There must be a natural mechanism to regulate reactor power level, and; (8) The location of the reactor or must be such as to provide containment and prevent meltdown. Herndon's georeactor alone is shown to meet those conditions. Georeactor existence evidence based upon helium measurements and upon antineutrino measurements is described. Geophysical implications discussed include georeactor origin of the geomagnetic field, geomagnetic reversals from intense solar outbursts and severe Earth trauma, as well as georeactor heat contributions to global dynamics.

J. Marvin Herndon

2013-12-31T23:59:59.000Z

457

Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures  

SciTech Connect (OSTI)

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2013-11-01T23:59:59.000Z

458

The cosmic X-ray and gamma-ray background from dark matter annihilation  

E-Print Network [OSTI]

(Abridged) The extragalactic background light (EBL) observed at multiple wavelengths is a promising tool to probe the nature of dark matter since it might contain a significant contribution from gamma-rays produced promptly by dark matter annihilation. Additionally, the electrons and positrons produced in the annihilation give energy to the CMB photons to populate the EBL with X-rays and gamma-rays. We here create full-sky maps of the radiation from both of these contributions using the high-resolution Millennium-II simulation. We use upper limits on the contributions of unknown sources to the EBL to constrain the intrinsic properties of dark matter using a model-independent approach that can be employed as a template to test different particle physics models (including those with a Sommerfeld enhancement). These upper limits are based on observations spanning eight orders of magnitude in energy (from soft X-rays measured by CHANDRA to gamma-rays measured by Fermi), and on expectations for the contributions f...

Zavala, Jesus; Slatyer, Tracy R; Loeb, Abraham; Springel, Volker

2011-01-01T23:59:59.000Z

459

On the ultra high energy cosmic rays and the origin of the cosmic microwave background radiation  

E-Print Network [OSTI]

Some inconsistencies to the assumption of a cosmological origin of the cosmic microwave background CMB, such as the absence of gravitational lensing in the WMAP data, open the doors to some speculations such as a local origin to the CMB. We argue here that this assumption agrees with the absence of the GZK cutoff (at least according to AGASA data) in the energy spectrum of the cosmic ray due to the cosmic interaction with the CMB at $6\\times 10^{19} eV$ or above. Within 50 Mpc from Earth, the matter and light distributions are close to an anisotropic distribution, where the local cluster and local super-clusters of galaxies can be identified. In contrast, the ultra high energy comic rays data is consistent to an almost isotropic distribution, and there is no correlation between their arrival direction and astronomical sources within our local cluster. This means that the events above the GZK cutoff come from distances above 50 Mpc, without an apparent energy loss. This scenario is plausible under the assumption of the CMB concentrated only within 3-4 Mpc from Earth. In other words, the CMB has a local origin linked only to the local super-cluster of galaxies. In addition, the galactic and extragalactic energy spectra index within the energy equipartition theorem strongly constrains the dark matter and dark energy hypothesis, essential in the Big Bang cosmology.

C. E. Navia; C. R. A. Augusto; K. H. Tsui

2007-07-12T23:59:59.000Z

460

Thin-shell bubbles and information loss problem in anti de Sitter background  

E-Print Network [OSTI]

We study the motion of thin-shell bubbles and their tunneling in anti de Sitter (AdS) background. We are interested in the case when the outside of a shell is a Schwarzschild-AdS space (false vacuum) and the inside of it is an AdS space with a lower vacuum energy (true vacuum). If a collapsing true vacuum bubble is created, classically it will form a Schwarzschild-AdS black hole. However, this collapsing bubble can tunnel to a bouncing bubble that moves out to spatial infinity. Then, although the classical causal structure of a collapsing true vacuum bubble has the singularity and the event horizon, quantum mechanically the wavefunction has support for a history without any singularity nor event horizon which is mediated by the non-perturbative, quantum tunneling effect. This may be regarded an explicit example that shows the unitarity of an asymptotic observer in AdS, while a classical observer who only follows the most probable history effectively lose information due to the formation of an event horizon.

Misao Sasaki; Dong-han Yeom

2014-12-25T23:59:59.000Z

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461

Cosmogenic Backgrounds in Borexino at 3800 m water-equivalent depth  

SciTech Connect (OSTI)

The solar neutrino experiment Borexino, which is located in the Gran Sasso underground laboratories, is in a unique position to study muon-induced backgrounds in an organic liquid scintillator. In this study, a large sample of cosmic muons is identified and tracked by a muon veto detector external to the liquid scintillator, and by the specific light patterns observed when muons cross the scintillator volume. The yield of muon-induced neutrons is found to be Y{sub n} = (3.100.11)10{sup ?4} n/(?(g/cm{sup 2})). The distance profile between the parent muon track and the neutron capture point has the average value ? = (81.52.7) cm. Additionally the yields of a number of cosmogenic radioisotopes are measured for {sup 12}N, {sup 12}B, {sup 8}He, {sup 9}C, {sup 9}Li, {sup 8}B, {sup 6}He, {sup 8}Li, {sup 11}Be, {sup 10}C and {sup 11}C. All results are compared with Monte Carlo simulation predictions using the FLUKA and GEANT4 packages. General agreement between data and simulation is observed for the cosmogenic production yields with a few exceptions, the most prominent case being {sup 11}C yield for which both codes return about 50% lower values. The predicted ?-n distance profile and the neutron multiplicity distribution are found to be overall consistent with data.

Bellini, G.; Avanzini, M. Buizza; Caccianiga, B.; D'Angelo, D. [Dipartimento di Fisica, Universit degli Studi e INFN, Milano 20133 (Italy); Benziger, J. [Chemical Engineering Department, Princeton University, Princeton, NJ 08544 (United States); Bick, D. [University of Hamburg, Hamburg (Germany); Bonfini, G.; Cavalcante, P.; Fomenko, K. [INFN Laboratori Nazionali del Gran Sasso, Assergi 67010 (Italy); Bravo, D. [Physics Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Cadonati, L. [Physics Department, University of Massachusetts, Amherst 01003 (United States); Calaprice, F.; Chavarria, A.; Galbiati, C. [Physics Department, Princeton University, Princeton, NJ 08544 (United States); Chepurnov, A. [Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, Moscow 119234 (Russian Federation); Davini, S.; Empl, A. [Department of Physics, University of Houston, Houston, TX 77204 (United States); Derbin, A. [St. Petersburg Nuclear Physics Institute, Gatchina 188350 (Russian Federation); Etenko, A. [NRC Kurchatov Institute, Moscow 123182 (Russian Federation); Franco, D., E-mail: spokeperson-borex@lngs.infn.it [APC, Univ. Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs. de Paris, Sorbonne Paris Cit (France); and others

2013-08-01T23:59:59.000Z

462

Internal combustion engines for alcohol motor fuels: a compilation of background technical information  

SciTech Connect (OSTI)

This compilation, a draft training manual containing technical background information on internal combustion engines and alcohol motor fuel technologies, is presented in 3 parts. The first is a compilation of facts from the state of the art on internal combustion engine fuels and their characteristics and requisites and provides an overview of fuel sources, fuels technology and future projections for availability and alternatives. Part two compiles facts about alcohol chemistry, alcohol identification, production, and use, examines ethanol as spirit and as fuel, and provides an overview of modern evaluation of alcohols as motor fuels and of the characteristics of alcohol fuels. The final section compiles cross references on the handling and combustion of fuels for I.C. engines, presents basic evaluations of events leading to the use of alcohols as motor fuels, reviews current applications of alcohols as motor fuels, describes the formulation of alcohol fuels for engines and engine and fuel handling hardware modifications for using alcohol fuels, and introduces the multifuel engines concept. (LCL)

None

1980-11-01T23:59:59.000Z

463

Constraints on primordial magnetic fields from the optical depth of the cosmic microwave background  

E-Print Network [OSTI]

Damping of magnetic fields via ambipolar diffusion and decay of magnetohydrodynamical (MHD) turbulence in the post decoupling era heats the intergalactic medium (IGM). Collisional ionization weakly ionizes the IGM, producing an optical depth to scattering of the cosmic microwave background (CMB). The optical depth generated at $z\\gg 10$ does not affect the "reionization bump" of the CMB polarization power spectrum at low multipoles, but affects the temperature and polarization power spectra at high multipoles. Using the Planck 2013 temperature and lensing data together with the WMAP 9-year polarization data, we constrain the present-day field strength, $B_0$, smoothed over the damping length at the decoupling epoch as a function of the spectral index, $n_B$. We find the 95% upper bounds of $B_0<0.56$, 0.31, and 0.14 nG for $n_B=-2.9$, $-2.5$, and $-1.5$, respectively. For these spectral indices, the optical depth is dominated by dissipation of the decaying MHD turbulence that occurs shortly after the decou...

Kunze, Kerstin E

2015-01-01T23:59:59.000Z

464

Nonlinear Evolution of Cosmic Magnetic Fields and Cosmic Microwave Background Anisotropies  

E-Print Network [OSTI]

In this work we investigate the effects of the primordial magnetic fields on cosmic microwave background anisotropies (CMB). Based on cosmological magnetohydrodynamic (MHD) simulations we calculate the CMB anisotropy spectra and polarization induced by fluid fluctuations (Alfv\\'en modes) generated by primordial magnetic fields. The strongest effect on the CMB spectra comes from the transition epoch from a turbulent regime to a viscous regime. The balance between magnetic and kinetic energy until the onset of the viscous regime provides a one to one relation between the comoving coherence length $L$ and the comoving magnetic field strength $B$, such as $L \\sim 30 (B/10^{-9}{\\rm G})^3 \\rm pc$. The resulting CMB temperature and polarization anisotropies are somewhat different from the ones previously obtained by using linear perturbation theory. Our calculation gives a constraint on the magnetic field strength in the intermediate scale of CMB observations. Upper limits are set by WMAP and BOOMERANG results for comoving magnetic field strength of $B 0.7 \\rm Mpc$ for the most extreme case, or $B 0.8 \\rm Mpc$ for the most conservative case.

Hiroyuki Tashiro; Naoshi Sugiyama; Robi Banerjee

2006-01-14T23:59:59.000Z

465

Statistical characterisation of bio-aerosol background in an urban environment  

E-Print Network [OSTI]

In this paper we statistically characterise the bio-aerosol background in an urban environment. To do this we measure concentration levels of naturally occurring microbiological material in the atmosphere over a two month period. Naturally occurring bioaerosols can be considered as noise, as they mask the presence of signals coming from biological material of interest (such as an intentionally released biological agent). Analysis of this 'biobackground' was undertaken in the 1-10 um size range and a 3-9% contribution was found to be biological in origin - values which are in good agreement with other studies reported in the literature. A model based on the physics of turbulent mixing and dispersion was developed and validated against this analysis. The Gamma distribution (the basis of our model) is shown to comply with the scaling laws of the concentration moments of our data, which enables us to universally characterise both biological and non-biological material in the atmosphere. An application of this model is proposed to build a framework for the development of novel algorithms for bio-aerosol detection and rapid characterisation.

Milan Jamriska; Timothy C. DuBois; Alex Skvortsov

2011-10-26T23:59:59.000Z

466

A Study of External Galaxies Detected by the {ital COBE} Diffuse Infrared Background Experiment  

SciTech Connect (OSTI)

A comparison of the {ital COBE} Diffuse Infrared Background Experiment (DIRBE) all-sky survey with the locations of known galaxies in the {ital IRAS} Catalog of Extragalactic Objects and the Center for Astrophysics Catalog of Galaxies led to the detection of as many as 57 galaxies. In this paper, we present the photometric data for these galaxies and an analysis of the seven galaxies that were detected at {lambda} {gt} 100 {mu}m. Estimates of the ratio of the mass of the cold dust (CD) component detected at {ital T}{sub {ital d}} = 20{endash}30 K to a very cold dust (VCD) component with {ital T}{sub {ital d}} {approx} 10{endash}15 K suggest that between 2{percent}{endash}100{percent} of the cirrus-like CD mass can also exist in many of these galaxies as VCD. In one galaxy, M33, the DIRBE photometry at 240 {mu}m suggests as much as 26 times as much VCD may be present as compared to the cirrus-like component. Further submillimeter measurements of this galaxy are required to verify such a large population of VCD. We also present 10 galaxies that were detected in the sky region not previously surveyed by {ital IRAS} and that can be used to construct a flux-limited all-sky catalog of galaxies brighter than 1000 Jy with a modest completeness limit of about 65{percent}. {copyright} {ital {copyright} 1998.} {ital The American Astronomical Society}

Odenwald, S. [Raytheon STX, Code 630.0, Goddard SFC, Greenbelt, MD 20771 (United States)] [Raytheon STX, Code 630.0, Goddard SFC, Greenbelt, MD 20771 (United States); Newmark, J. [Applied Research Corporation, Landover, MD 20785 (United States)] [Applied Research Corporation, Lan