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1

Ultrahigh Energy Cosmic Rays Detection  

Science Conference Proceedings (OSTI)

The paper describes methods used for the detection of cosmic rays with energies above 1018 eV (UHECR

Carla Aramo

2005-01-01T23:59:59.000Z

2

Frontiers in Cosmic Rays  

E-Print Network (OSTI)

This rapporteur review covers selected results presented in the Parallel Session HEA2 (High Energy Astrophysics 2) of the 10th Marcel Grossmann Meeting on General Relativity, held in Rio de Janeiro, Brazil, July 2003. The subtopics are: ultra high energy cosmic ray anisotropies, the possible connection of these energetic particles with powerful gamma ray bursts, and new exciting scenarios with a strong neutrino-nucleon interaction in the atmosphere.

Luis A. Anchordoqui; Charles D. Dermer; Andreas Ringwald

2004-02-27T23:59:59.000Z

3

Cosmic Ray Telescopes  

NLE Websites -- All DOE Office Websites (Extended Search)

Cosmic Ray Muon Detectors Cosmic Ray Muon Detectors Particle Physics Using Nature's Accelerator Somewhere out there is a list of "10 Things a Physics Teacher is Least Likely to Say." If one were to find this list, it would have on it such gems as #7. Let's challenge the PE Dept to a game of rugby and #4. I don't care if you understand the concept, just give me the correct answer to 12 sig figs. Finally, you'd get down to the biggie, the thing physics teachers never say: #1. Let's do a particle physics lab right here at Podunk Corners High! The traditional reasons for this are that everyone knows that particle physics is only done with Vastly Expensive and Complicated Equipment run by casts of thousands of Highly Qualified Scientists and that particle physics is Difficult and Arcane.

4

High Energy Cosmic Rays  

E-Print Network (OSTI)

.Hebbeker Radiation Exposure of Humans Natural sources: ~ 1 m Sv / year ~ 1 m Gy / year ~ 0,1 J / year Technical sources: ~ 1 m Sv / Jahr ~ natural exposure Air (Radon) internal radioactivity (K-40) cosmics Increased of Cosmic Radiation Nobel 1936 1912 Viktor Hess 1912 #12;T.Hebbeker Electrometer Measurements V. Hess

Hebbeker, Thomas

5

Cosmic-ray sum rules  

SciTech Connect

We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays; we show how they can be used to predict the positron fraction at energies not yet explored by current experiments, and to constrain specific models.

Frandsen, Mads T. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Masina, Isabella [Dip. di Fisica dell'Universita di Ferrara and INFN Sez. di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy); CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Sannino, Francesco [CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

2011-06-15T23:59:59.000Z

6

High-energy Cosmic Rays  

E-Print Network (OSTI)

After a brief review of galactic cosmic rays in the GeV to TeV energy range, we describe some current problems of interest for particles of very high energy. Particularly interesting are two features of the spectrum, the `knee' above $10^{15}$ eV and the `ankle' above $10^{18}$ eV. An important question is whether the highest energy particles are of extra-galactic origin and, if so, at what energy the transition occurs. A theme common to all energy ranges is use of nuclear abundances as a tool for understanding the origin of the cosmic radiation.

Thomas K. Gaisser; Todor Stanev

2005-10-11T23:59:59.000Z

7

Cosmic Rays and Gamma Ray Bursts From Microblazars  

E-Print Network (OSTI)

Highly relativistic jets from merger and accretion induced collapse of compact stellar objects, which may produce the cosmological gamma ray bursts (GRBs), are also very efficient and powerful cosmic ray accelerators. The expected luminosity, energy spectrum and chemical composition of cosmic rays from Galactic GRBs, most of which do not point in our direction, can explain the observed properties of Galactic cosmic rays.

Arnon Dar

1998-09-13T23:59:59.000Z

8

High-energy cosmic ray interactions  

SciTech Connect

Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand--due to the indirect observation of cosmic rays through air showers--the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

Engel, Ralph [Forschungszentrum Karlsruhe, P.O. Box 3640, 76021 Karlsruhe (Germany); Orellana, Mariana [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina); Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque, 1900 La Plata (Argentina); Reynoso, Matias M. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Investigaciones Fisicas de Mar del Plata, (UNMdP-CONICET) (Argentina); Vila, Gabriela S. [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina)

2009-04-30T23:59:59.000Z

9

Are High Energy Cosmic Rays Magnetic Monopoles?  

E-Print Network (OSTI)

We argue that magnetic monopoles can not be associated to the highest energy cosmic rays as recently suggested. Both the observed spectrum and the arrival direction disagree with observation.

C. O. Escobar; R. A. Vázquez

1997-09-15T23:59:59.000Z

10

Cosmic ray propagation in galactic turbulence  

E-Print Network (OSTI)

We revisit propagation of galactic cosmic rays in light of recent advances in cosmic ray diffusion theory in realistic interstellar turbulence. We use tested model of turbulence in which it has been shown that fast modes dominate scattering of cosmic rays. As a result, propagation becomes inhomogeneous and environment dependent. By adopting the formalism of the nonlinear theory (NLT) developed by Yan & Lazarian (2008), we calculate diffusion of cosmic rays self-consistently from first principles. We assume a two-phase model for the Galaxy to account for different damping mechanisms of the fast modes, and we find that the energy dependence of the diffusion coefficient is mainly affected by medium properties. We show that it gives a correct framework to interpret some of the recent CR puzzles.

Evoli, Carmelo

2013-01-01T23:59:59.000Z

11

Gamma Ray Bursts from Ordinary Cosmic Strings  

E-Print Network (OSTI)

We give an upper estimate for the number of gamma ray bursts from ordinary (non-superconducting) cosmic strings expected to be observed at terrestrial detectors. Assuming that cusp annihilation is the mechanism responsible for the bursts we consider strings arising at a GUT phase transition and compare our estimate with the recent BATSE results. Further we give a lower limit for the effective area of future detectors designed to detect the cosmic string induced flux of gamma ray bursts.

R. H. Brandenberger; A. T. Sornborger; M. Trodden

1993-02-12T23:59:59.000Z

12

Radiodetection of Cosmic Ray Extensive Air Showers  

E-Print Network (OSTI)

We present the characteristics and performance of a demonstration experiment devoted to the observation of ultra high- energy cosmic ray extensive air showers using a radiodetection technique. In a first step, one antenna narrowed band filtered acting as trigger, with a 4 $\\sigma$ threshold above sky background-level, was used to tag any radio transient in coincidence on the antenna array. Recently, the addition of 4 particle detectors has allowed us to observe cosmic ray events in coincidence with antennas.

D. Ardouin; A. Belletoile; D. Charrier; R. Dallier; L. Denis; P. Eschstruth; T. Gousset; F. Haddad; J. Lamblin; P. Lautridou; A. Lecacheux; D. Monnier-Ragaiggne; A. Rahmani; O. Ravel; the Codalema Collaboration

2004-12-09T23:59:59.000Z

13

Cosmic Ray Interactions in Shielding Materials  

SciTech Connect

This document provides a detailed study of materials used to shield against the hadronic particles from cosmic ray showers at Earth’s surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during transport for the MAJORANA collaboration. The materials suitable for cosmic-ray shield design are materials such as lead and iron that will stop the primary protons, and materials like polyethylene, borated polyethylene, concrete and water that will stop the induced neutrons. The interaction of the different cosmic-ray components at ground level (protons, neutrons, muons) with their wide energy range (from kilo-electron volts to giga-electron volts) is a complex calculation. Monte Carlo calculations have proven to be a suitable tool for the simulation of nucleon transport, including hadron interactions and radioactive isotope production. The industry standard Monte Carlo simulation tool, Geant4, was used for this study. The result of this study is the assertion that activation at Earth’s surface is a result of the neutronic and protonic components of the cosmic-ray shower. The best material to shield against these cosmic-ray components is iron, which has the best combination of primary shielding and minimal secondary neutron production.

Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Ankney, Austin S.; Orrell, John L.; Berguson, Timothy J.; Troy, Meredith D.

2011-09-08T23:59:59.000Z

14

Detectors of Cosmic Rays, Gamma Rays, and Neutrinos  

SciTech Connect

We summarize the main features, properties and performances of the typical detectors in use in Cosmic Ray Physics. A brief historical and general introduction will focus on the main classes and requirements of such detectors.

Altamirano, A. [Departamento de Fisica, Informatica y Matematicas, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia (Peru); Centro de Tecnologias de Informacion y Comunicaciones (CTIC), Universidad Nacional de Ingenieria, Lima (Peru); Navarra, G. [Dipartimento di Fisica Generale dell'Universita' and INFN, Torino (Italy)

2009-04-30T23:59:59.000Z

15

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

1998-10-14T23:59:59.000Z

16

Ultrahigh Energy Cosmic Rays: New Physics or Old Physics?  

E-Print Network (OSTI)

We consider the advantages of and the problems associated with hypotheses to explain the origin of ulthrahigh energy cosmic rays (UHECR: E > 10 EeV) and the "trans GZK" cosmic rays (TGZK: E > 100 EeV), both through "old physics" (acceleration in cosmic sources) and "new physics" (new particles, topological defects, fat neutrino cross sections, Lorentz invariance violation).

F. W. Stecker

2004-07-15T23:59:59.000Z

17

Ultra High-Energy Cosmic Ray Observations  

E-Print Network (OSTI)

The year 2007 has furnished us with outstanding results about the origin of the most energetic cosmic rays: a flux suppression as expected from the GZK-effect has been observed in the data of the HiRes and Auger experiments and correlations between the positions of nearby AGN and the arrival directions of trans-GZK events have been observed by the Pierre Auger Observatory. The latter finding marks the beginning of ultra high-energy cosmic ray astronomy and is considered a major breakthrough starting to shed first light onto the sources of the most extreme particles in nature. This report summarizes those observations and includes other major advances of the field, mostly presented at the 30th International Cosmic Ray Conference held in Merida, Mexico, in July 2007. With increasing statistics becoming available from current and even terminated experiments, systematic differences amongst different experiments and techniques can be studied in detail which is hoped to improve our understanding of experimental tec...

Kampert, Karl-Heinz

2008-01-01T23:59:59.000Z

18

The intergalactic propagation of ultrahigh energy cosmic ray nuclei  

SciTech Connect

We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.

2006-08-01T23:59:59.000Z

19

Muon Acceleration in Cosmic-ray Sources  

E-Print Network (OSTI)

Many models of ultra-high energy cosmic-ray production involve acceleration in linear accelerators located in Gamma-Ray Bursts magnetars, or other sources. These source models require very high accelerating gradients, $10^{13}$ keV/cm, with the minimum gradient set by the length of the source. At gradients above 1.6 keV/cm, muons produced by hadronic interactions undergo significant acceleration before they decay. This acceleration hardens the neutrino energy spectrum and greatly increases the high-energy neutrino flux. We rule out many models of linear acceleration, setting strong constraints on plasma wakefield accelerators and on models for sources like Gamma Ray Bursts and magnetars.

Spencer R. Klein; Rune Mikkelsen; Julia K. Becker Tjus

2012-08-09T23:59:59.000Z

20

Upgrade To The Pierre Auger Cosmic Ray Observatory's Lidar System.  

E-Print Network (OSTI)

??The Pierre Auger Cosmic Ray Observatory currently operates four elastic lidar systems in order to characterize the atmospheric aerosol content above the observatory. The atmospheric… (more)

Petermann, Emily B

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Supersymmetry and the Cosmic Ray Positron Excess  

SciTech Connect

We explore several supersymmetric alternatives to explain predictions for the cosmic ray positron excess. Light sneutrino or neutralino LSP's, and a fine-tuned model designed to provide a delta-function input, can give adequate statistical descriptions of the reported HEAT data if non-thermal production of the relic cold dark matter density dominates and/or if"boost factors" (that could originate in uncertainties from propagation or local density fluctuations) to increase the size of the signal are included. All the descriptions can be tested at the Tevatron or LHC, and some in other WIMP detecting experiments.

Kane, Gordon L.; Wang, Lian-Tao; Wang, Ting T.

2002-02-15T23:59:59.000Z

22

High-Energy Cosmic Ray Event Data from the Pierre Auger Cosmic Ray Observatory  

DOE Data Explorer (OSTI)

The Pierre Auger Cosmic Ray Observatory in Mendoza, Argentina is the result of an international collaboration funded by 15 countries and many different organizations. Its mission is to capture high-energy cosmic ray events or air showers for research into their origin and nature. The Pierre Auger Collaboration agreed to make 1% of its data available to the public. The ôPublic Event Explorerö is a search tool that allows users to browse or search for and display figures and data plots of events collected since 2004. The repository is updated daily, and, as of July, 2009, makes 14,055 events publicly available. The energy of a cosmic ray is measured in Exa electron volts or EeV. These event displays can be browsed in order of their energy level from 0.1 to 41.1 EeV. Each event has an individual identification number.

The event displays provide station data, cosmic ray incoming direction, various energy measurements, plots, vector-based images, and an ASCII data file.

None

23

THE COSMIC-RAY INTENSITY NEAR THE ARCHEAN EARTH  

Science Conference Proceedings (OSTI)

We employ three-dimensional state-of-the-art magnetohydrodynamic models of the early solar wind and heliosphere and a two-dimensional model for cosmic-ray transport to investigate the cosmic-ray spectrum and flux near the Archean Earth. We assess how sensitive the cosmic-ray spectrum is to changes in the sunspot placement and magnetic field strength, the large-scale dipole magnetic field strength, the wind ram pressure, and the Sun's rotation period. Overall, our results confirm earlier work that suggested the Archean Earth would have experienced a greatly reduced cosmic-ray flux than is the case today. The cosmic-ray reduction for the early Sun is mainly due to the shorter solar rotation period and tighter winding of the Parker spiral, and to the different surface distribution of the more active solar magnetic field. These effects lead to a global reduction of the cosmic-ray flux at 1 AU by up to two orders of magnitude or more. Variations in the sunspot magnetic field have more effect on the flux than variations in the dipole field component. The wind ram pressure affects the cosmic-ray flux through its influence on the size of the heliosphere via the pressure balance with the ambient interstellar medium. Variations in the interstellar medium pressure experienced by the solar system in orbit through the Galaxy could lead to order of magnitude changes in the cosmic-ray flux at Earth on timescales of a few million years.

Cohen, O.; Drake, J. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kota, J. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States)

2012-11-20T23:59:59.000Z

24

The Revival of Galactic Cosmic Ray Nucleosynthesis?  

E-Print Network (OSTI)

Because of the roughly linear correlation between Be/H and Fe/H in low metallicity halo stars, it has been argued that a ``primary'' component in the nucleosynthesis of Be must be present in addition to the ``secondary'' component from standard Galactic cosmic ray nucleosynthesis. In this paper we critically re-evaluate the evidence for the primary versus secondary character of Li, Be, and B evolution, analyzing both in the observations and in Galactic chemical evolution models. While it appears that [Be/H] versus [Fe/H] has a logarithmic slope near 1, it is rather the Be-O trend that directly arises from the physics of spallation production. Using new abundances for oxygen in halo stars based on UV OH lines, we find that the Be-O slope has a large uncertainty due to systematic effects, rendering it difficult to distinguish from the data between the secondary slope of 2 and the primary slope of 1. The possible difference between the Be-Fe and Be-O slopes is a consequence of the variation in O/Fe versus Fe: recent data suggests a negative slope rather than zero (i.e., Fe $\\propto$ O) as is often assumed. In addition to a phenomenological analysis of Be and B evolution, we have also examined the predicted LiBeB, O, and Fe trends in Galactic chemical evolution models which include outflow. Based on our results, it is possible that a good fit to the LiBeB evolution requires only traditional the Galactic cosmic ray spallation, and the (primary) neutrino-process contribution to B11. We thus suggest that these two processes might be sufficient to explain Li6, Be, and B evolution in the Galaxy, without the need for an additional primary source of Be and B.

Brian D. Fields; Keith A. Olive

1998-09-22T23:59:59.000Z

25

Cosmic  

NLE Websites -- All DOE Office Websites (Extended Search)

below about 10 GeV. In addition, the lower-energy cosmic rays are affected by the geomagnetic field, which they must penetrate to reach the top of the atmosphere. Thus the...

26

Solar Variability, Cosmic Rays and Climate: What's up? The topic of possible relations between solar and cosmic  

E-Print Network (OSTI)

Preface Solar Variability, Cosmic Rays and Climate: What's up? The topic of possible relations between solar and cosmic ray variability on one hand, and Earth's climate on the other hand, is quite in Space Research topical issue on Solar Variability, Cosmic Rays and Climate presents a collection

Usoskin, Ilya G.

27

Cosmic ray lithium isotope measurement with AMS-01  

E-Print Network (OSTI)

The AMS-01 detector measured charged cosmic rays during 10 days on the Space Shuttle Discovery in 1998 and collected 108 events. By identifying 8349 Lithium and 22709 Carbon nuclei from the raw data, this thesis presents ...

Zhou, Feng, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

28

Influence of solar and cosmic-ray variability on climate  

E-Print Network (OSTI)

We analyze solar, geomagnetic and cosmic ray flux data along with rainfall and temperature data for almost five solar cycles. We provide evidence of significant influence of solar variability on climate. Specifically, we demonstrate association between lower (higher) rainfall and higher (lower) temperatures with increasing (decreasing) solar activity and decreasing (increasing) cosmic ray intensities. We propose a plausible scenario that accounts the results of our analysis.

Badruddin,; Singh, M

2013-01-01T23:59:59.000Z

29

Cosmic Ray Spectrum in Supernova Remnant Shocks  

E-Print Network (OSTI)

We perform kinetic simulations of diffusive shock acceleration (DSA) in Type Ia supernova remnants (SNRs) expanding into a uniform interstellar medium (ISM). Bohm-like diffusion assumed, and simple models for Alfvenic drift and dissipation are adopted. Phenomenological models for thermal leakage injection are considered as well. We find that the preshock gas temperature is the primary parameter that governs the cosmic ray (CR) acceleration efficiency and energy spectrum, while the CR injection rate is a secondary parameter. For SNRs in the warm ISM, if the injection fraction is larger than 10^{-4}, the DSA is efficient enough to convert more than 20 % of the SN explosion energy into CRs and the accelerated CR spectrum exhibits a concave curvature flattening to E^{-1.6}. Such a flat source spectrum near the knee energy, however, may not be reconciled with the CR spectrum observed at Earth. On the other hand, SNRs in the hot ISM, with an injection fraction smaller than 10^{-4}, are inefficient accelerators with...

Kang, Hyesung

2010-01-01T23:59:59.000Z

30

A Cosmic Ray Telescope For Educational Purposes  

SciTech Connect

Cosmic ray detectors are widely used, for educational purposes, in order to motivate students to the physics of elementary particles and astrophysics. Using a 'telescope' of scintillation counters, the directional characteristics, diurnal variation, correlation with solar activity, can be determined, and conclusions about the composition, origin and interaction of elementary particles with the magnetic field of earth can be inferred. A telescope was built from two rectangular scintillator panels with dimensions: 91.6x1.9x3.7 cm{sup 3}. The scintillators are placed on top of each other, separated by a fixed distance of 34.6 cm. They are supported by a wooden frame which can be rotated around a horizontal axis. Direction is determined by the coincidence of the signals of the two PMTs. Standard NIM modules are used for readout. This device is to be used in the undergraduate nuclear and particle physics laboratory. The design and construction of the telescope as well as some preliminary results are presented.

Voulgaris, G.; Kazanas, S.; Chamilothoris, I. [Department of Physics, National and Kapodistrian University of Athens (Greece)

2010-01-21T23:59:59.000Z

31

Cosmic Rays and the Monogem Supernova Remnant  

E-Print Network (OSTI)

Recent findings indicate that the Monogem Ring supernova remnant (SNR) and the associated pulsar B0656+14 may be the 'Single Source' responsible for the knee in the cosmic ray (CR) energy spectrum at ~3 PeV. We estimate the contribution of this pulsar to CR in the PeV region. We conclude that although the pulsar can contribute to the formation of the knee, it cannot be the domimant source and a SNR is still needed. We also examine the possibility of the pulsar giving the peak of the extensive air shower (EAS) intensity observed from the region inside the Monogem Ring. If the experimental EAS results concerning a narrow source are confirmed, they can be important, since they give evidence: (i) for the acceleration of protons and heavier nuclei by the pulsar; (ii) for the existence of the confinement mechanism in SNR; (iii) that CR produced by the Monogem Ring SNR and associated pulsar B0656+14 were released recently giving rise to the formation of the knee and the observed narrow peak in the EAS intensity; (iv) for the Monogem Ring and the associated pulsar B0656+14 being identified as the Single Source proposed in our Single Source Model of the knee. A number of predictions of the examined scenario are made.

A. D. Erlykin; A. W. Wolfendale

2004-04-27T23:59:59.000Z

32

Are extragalactic gamma ray bursts the source of the highest energy cosmic rays?  

E-Print Network (OSTI)

Recent observations with the large air shower arrays of ultra high energy cosmic rays (UHECR) and recent measurements/estimates of the redshifts of gamma ray bursts (GRBs) seem to rule out extragalactic GRBs as the source of the cosmic rays that are observed near Earth, including those with the highest energies.

Arnon Dar

1999-01-03T23:59:59.000Z

33

Lithium-6 and Gamma Rays: Complementary Constraints on Cosmic-Ray History  

E-Print Network (OSTI)

The rare isotope 6Li is made only by cosmic rays, dominantly in alpha+alpha fusion reactions with ISM helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays in our Galaxy. The same hadronic cosmic-ray interactions also produce high-energy gamma rays (mostly via neutral pion production). Thus, hadronic gamma-rays and 6Li are intimately linked. Specifically, 6Li directly encodes the local cosmic-ray fluence over cosmic time, while extragalactic hadronic gamma rays encode an average cosmic-ray fluence over lines of sight out to the horizon. We examine this link and show how 6Li and gamma-rays can be used together to place important model-independent limits on the cosmic-ray history of our Galaxy and the universe. We first constrain gamma-ray production from ordinary Galactic cosmic rays, using the local 6Li abundance. We find that the solar 6Li abundance demands an accompanying extragalactic pionic gamma-ray intensity which exceeds that of the entire observed EGRB by a factor of 2-6. Possible explanations for this discrepancy are discussed. We then constrain Li production using recent determinations of extragalactic gamma-ray background (EGRB). We note that cosmic rays created during cosmic structure formation would lead to pre-Galactic Li production, which would act as a "contaminant" to the primordial 7Li content of metal-poor halo stars. We find the uncertainties in the observed EGRB are so large that we cannot exclude a pre-Galactic Li which is comparable to primordial 7Li. Our limits and their more model-dependent extensions will improve significantly with additional observations of 6Li in halo stars, and with improved measurements of the EGRB spectrum by GLAST. (Abriged abstract)

Brian D. Fields; Tijana Prodanovic

2004-07-15T23:59:59.000Z

34

Feedback Heating by Cosmic Rays in Clusters of Galaxies  

E-Print Network (OSTI)

Recent observations show that the cooling flows in the central regions of galaxy clusters are highly suppressed. Observed AGN-induced cavities/bubbles are a leading candidate for suppressing cooling, usually via some form of mechanical heating. At the same time, observed X-ray cavities and synchrotron emission point toward a significant non-thermal particle population. Previous studies have focused on the dynamical effects of cosmic-ray pressure support, but none have built successful models in which cosmic-ray heating is significant. Here we investigate a new model of AGN heating, in which the intracluster medium is efficiently heated by cosmic-rays, which are injected into the ICM through diffusion or the shredding of the bubbles by Rayleigh-Taylor or Kelvin-Helmholtz instabilities. We include thermal conduction as well. Using numerical simulations, we show that the cooling catastrophe is efficiently suppressed. The cluster quickly relaxes to a quasi-equilibrium state with a highly reduced accretion rate and temperature and density profiles which match observations. Unlike the conduction-only case, no fine-tuning of the Spitzer conduction suppression factor f is needed. The cosmic ray pressure, P_c/P_g alternative to mechanical heating, and may become particularly compelling if GLAST detects the gamma-ray signature of cosmic-rays in clusters.

Fulai Guo; S. Peng OH

2007-06-09T23:59:59.000Z

35

Cosmic-ray Propagation and Interactions in the Galaxy  

Science Conference Proceedings (OSTI)

We survey the theory and experimental tests for the propagation of cosmic rays in the Galaxy up to energies of 10{sup 15} eV. A guide to the previous reviews and essential literature is given, followed by an exposition of basic principles. The basic ideas of cosmic-ray propagation are described, and the physical origin of its processes are explained. The various techniques for computing the observational consequences of the theory are described and contrasted. These include analytical and numerical techniques. We present the comparison of models with data including direct and indirect--especially gamma-ray--observations, and indicate what we can learn about cosmic-ray propagation. Some particular important topics including electrons and antiparticles are chosen for discussion.

Strong, Andrew W.; /Garching, Max Planck Inst., MPE; Moskalenko, Igor V.; /Stanford U., HEPL /KIPAC, Menlo Park; Ptuskin, Vladimir S.; /Troitsk, IZMIRAN

2007-01-22T23:59:59.000Z

36

Chemical Composition of Galactic Cosmic Rays with Space Experiments  

E-Print Network (OSTI)

The origin and properties of the cosmic radiation are one of the most intriguing question in modern astrophysics. The precise measurement of the chemical composition and energy spectra of the cosmic rays provides fundamental insight into these subjects. In this paper we will review the existing experimental data. Specifically, we will analyse results collected by space-born experiments discussing the experimental uncertainties and challenges with a focus on the PAMELA experiment.

Mirko Boezio; Emiliano Mocchiutti

2012-08-07T23:59:59.000Z

37

Gamma Ray Bursts Cannot Produce the Observed Cosmic Rays Above 10 19 eV  

E-Print Network (OSTI)

Received; accepted – 2 – Using recent results indicating that the redshift distribution of ?-ray bursts most likely follows the redshift evolution of the star formation rate, I show that the energy input from these bursts at low redshifts is insufficient to account for the observed flux of ultrahigh energy cosmic rays with energies above 1019 eV. Subject Headings: gamma-rays: bursts — cosmic rays: theory – 3 – 1.

F. W. Stecker

1999-01-01T23:59:59.000Z

38

Ultrahigh Energy Cosmic Rays from Gamma Ray Bursts: Implications of the Recent Observational Results by Milagro  

E-Print Network (OSTI)

It has been speculated earlier that Gamma Ray Bursts are sources of ultrahigh energy cosmic rays. Recently, the search for high energy photons from Gamma Ray Bursts by Milagro group has put limits on the isotropic luminosity of these transient sources in very high energy photons. The implications of the results obtained by Milagro to our understanding of the ultrahigh energy cosmic ray spectrum from these sources have been discussed in the present work.

Nayantara Gupta

2004-06-03T23:59:59.000Z

39

Gamma-Rays from Grazing Incidence Cosmic Rays in the Earth’s Atmosphere  

E-Print Network (OSTI)

Interactions of grazing incidence, ultra high energy cosmic rays with the earth’s atmosphere may provide a new method of studying energetic cosmic rays with gamma-ray satellites. It is found that these cosmic ray interactions may produce gamma-rays on millisecond time scales which may be detectable by satellites. An extremely low gamma-ray background for transient gamma-ray events and a large area of interaction, the earth’s surface, make the scheme plausible. The effective cross section of detection of interactions for cosmic rays above 1020 eV is found to be more than two orders of magnitude higher than earth based detection techniques. This method may eventually offer an efficient way of probing this region of the cosmic ray energy spectrum where events are scarce. In this paper, a conceptual model is presented for the production of short bursts of gamma-rays based on these grazing incidence encounters with the earth’s atmosphere. Subject headings: atmospheric effects- cosmic rays- Earth- gamma-rays: bursts

Andrew Ulmer

1994-01-01T23:59:59.000Z

40

Are gamma-ray bursts the sources of ultra-high energy cosmic rays?  

E-Print Network (OSTI)

We reconsider the possibility that gamma-ray bursts (GRBs) are the sources of the ultra-high energy cosmic rays (UHECRs) within the internal shock model, assuming a pure proton composition of the UHECRs. For the first time, we combine the information from gamma-rays, cosmic rays, prompt neutrinos, and cosmogenic neutrinos quantitatively in a joint cosmic ray production and propagation model, and we show that the information on the cosmic energy budget can be obtained as a consequence. In addition to the neutron model, we consider alternative scenarios for the cosmic ray escape from the GRBs, i.e., that cosmic rays can leak from the sources. We find that the dip model, which describes the ankle in UHECR observations by the pair production dip, is strongly disfavored in combination with the internal shock model because a) unrealistically high baryonic loadings (energy in protons versus energy in electrons/gamma-rays) are needed for the individual GRBs and b) the prompt neutrino flux easily overshoots the corresponding neutrino bound. On the other hand, GRBs may account for the UHECRs in the ankle transition model if cosmic rays leak out from the source at the highest energies. In that case, we demonstrate that future neutrino observations can efficiently test most of the parameter space -- unless the baryonic loading is much larger than previously anticipated.

Philipp Baerwald; Mauricio Bustamante; Walter Winter

2014-01-08T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Cosmic Ray Sun Shadow in Soudan 2 Underground Muon Flux  

E-Print Network (OSTI)

The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. We report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a $3.3\\sigma$ shadow observed during the years 1995 to 1998.

Soudan 2 Collaboration

1999-05-24T23:59:59.000Z

42

Energy spectrum of ultra high energy cosmic rays  

E-Print Network (OSTI)

The construction of the southern site of the Pierre Auger Observatory is almost completed. Three independent measurements of the flux of the cosmic rays with energies larger than 1 EeV have been performed during the construction phase. The surface detector data collected until August 2007 have been used to establish a flux suppression at the highest energies with a 6 sigma significance. The observations of cosmic rays by the fluorescence detector allowed the extension of the energy spectrum to lower energies, where the efficiency of the surface detector is less than 100% and a change in the spectral index is expected.

Ioana C. Maris; for the Pierre Auger Collaboration

2008-08-12T23:59:59.000Z

43

Calibrating laser test-beams for cosmic-ray observatories  

E-Print Network (OSTI)

Pulsed UV lasers can provide useful "testbeams" for observatories that use optical detectors, especially fluorescence detectors, to measure high energy cosmic-rays. The light observed by the detector is proportional to the energy of the laser pulse. Since the absolute laser energy can be measured locally, a well-calibrated laser offers a practical way to test the photometric calibration of the cosmic-ray detector including atmospheric corrections. This poster will describe a robotic system for laser polarization and energy calibration. Laboratory measurements of laser energies and polarizations by energy probes from different manufactures will be presented

Wiencke, Lawrence; Compton, John; Monasor, Maria; Pilger, David; Rosado, Jaime

2011-01-01T23:59:59.000Z

44

Investigating Possible Links between Incoming Cosmic Ray Fluxes and Lightning Activity over the United States  

Science Conference Proceedings (OSTI)

During the past two decades, particular scientific attention has been drawn to the potential cosmic ray–atmospheric coupling. Galactic cosmic rays reaching the upper troposphere are suggested as the key modulators of the global electric circuit, ...

Themis G. Chronis

2009-11-01T23:59:59.000Z

45

THE RELATION BETWEEN POST-SHOCK TEMPERATURE, COSMIC-RAY PRESSURE, AND COSMIC-RAY ESCAPE FOR NON-RELATIVISTIC SHOCKS  

Science Conference Proceedings (OSTI)

Supernova remnants (SNRs) are thought to be the dominant source of Galactic cosmic rays. This requires that at least 5% of the available energy is transferred to cosmic rays, implying a high cosmic-ray pressure downstream of SNR shocks. Recently, it has been shown that the downstream temperature in some remnants is low compared to the measured shock velocities, implying that additional pressure supported by accelerated particles is present. Here we use a two-fluid thermodynamic approach to derive the relation between post-shock fractional cosmic-ray pressure and post-shock temperature, assuming no additional heating beyond adiabatic heating in the shock precursor and with all non-adiabatic heating occurring at the subshock. The derived relations show that a high fractional cosmic-ray pressure is only possible if a substantial fraction of the incoming energy flux escapes from the system. Recently, a shock velocity and a downstream proton temperature were measured for a shock in the SNR RCW 86. We apply the two-fluid solutions to these measurements and find that the downstream fractional cosmic-ray pressure is at least 50% with a cosmic-ray energy flux escape of at least 20%. In general, in order to have 5% of the supernova energy to go into accelerating cosmic rays, on average the post-shock cosmic-ray pressure needs to be 30% for an effective cosmic-ray adiabatic index of {gamma}{sub cr} = 4/3.

Vink, Jacco; Helder, Eveline A.; Schure, K. M. [Astronomical Institute, Utrecht University, P.O. Box 80000, 3508 TA Utrecht (Netherlands); Yamazaki, Ryo, E-mail: j.vink@astro-uu.n [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 252-5258 (Japan)

2010-10-20T23:59:59.000Z

46

Ultrahigh Energy Cosmic Rays and Prompt TeV Gamma Rays from Gamma Ray Bursts  

E-Print Network (OSTI)

Gamma Ray Bursts (GRBs) have been proposed as one {\\it possible} class of sources of the Ultrahigh Energy Cosmic Ray (UHECR) events observed up to energies $\\gsim10^{20}\\ev$. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up to TeV energies. Here we briefly discuss the implications on the energetics of the GRB from the point of view of the detectability of the prompt TeV gamma rays of proton-synchrotron origin in GRBs in the up-coming ICECUBE muon detector in the south pole.

Pijushpani Bhattacharjee; Nayantara Gupta

2003-05-12T23:59:59.000Z

47

QuarkNet/Walta/CROP Cosmic Ray Detectors  

E-Print Network (OSTI)

QuarkNet/Walta/CROP Cosmic Ray Detectors User's Manual Jeff Rylander and Tom Jordan, Fermilab R. J. Project Development Team Fermilab: Sten Hansen, Tom Jordan, Terry Kiper Univeristy of Nebraska: Dan Claes energies. However, it is possi- ble to do high-energy physics in your school without a particle accelerator

California at Santa Cruz, University of

48

DISCREPANT HARDENING OBSERVED IN COSMIC-RAY ELEMENTAL SPECTRA  

Science Conference Proceedings (OSTI)

The balloon-borne Cosmic Ray Energetics And Mass experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here, we report results from the first two flights of {approx}70 days, which indicate hardening of the elemental spectra above {approx}200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at {approx}10{sup 15} eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible explanations should also be investigated.

Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Lutz, L.; Malinin, A. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Allison, P.; Beatty, J. J. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States); Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S. [Department of Physics, University of Siena and INFN, Siena 53100 (Italy); Childers, J. T.; DuVernois, M. A. [School of Physics and Astronomy, University of Minnesota, MN 55414 (United States); Conklin, N. B.; Coutu, S.; Mognet, S. I. [Department of Physics, Penn State University, University Park, PA 16802 (United States); Jeon, J. A. [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Minnick, S. [Department of Physics, Kent State University Tuscarawas, New Philadelphia, OH 44663 (United States)], E-mail: seo@umd.edu (and others)

2010-05-01T23:59:59.000Z

49

Reference Radiation for Cosmic Rays in RBE Research  

E-Print Network (OSTI)

When astronauts travel in space, they are exposed to high energy cosmic radiations. The cosmic ray spectrum contains very high energy particles, generally up to several GeV per nucleon. Currently NASA is funding research on the effects, such as acute radiation sickness, of cosmic radiation. Animal models are used to conduct the studies of radiation effects of particles in the range of several MeV/nucleon to about 1000 MeV/nucleon. In order to compare different radiations, the biological effectiveness relative to a specific radiation is usually used. For low energy heavy ions and neutrons 250 keV photons are usually used for the reference radiation but their depth dose distribution is very different from that for cosmic rays. In this research, the advantages of using high energy electrons as the reference radiation for research on cosmic radiation were demonstrated. The conclusion is based on the evaluation of the dose distributions and microdosimetric spectra of the electrons and high energy protons as a function of depth in a tissue equivalent absorber as determined by Geant4 simulation.

Feng, Shaoyong

2010-08-01T23:59:59.000Z

50

On the Origin of Ultra High Energy Cosmic Rays II  

Science Conference Proceedings (OSTI)

We show that accretion disks around Active Galactic Nuclei (AGNs) could account for the enormous power in observed ultra high energy cosmic rays {approx}10{sup 20} eV (UHEs). In our model, cosmic rays are produced by quasi-steady acceleration of ions in magnetic structures previously proposed to explain jets around Active Galactic Nuclei with supermassive black holes. Steady acceleration requires that an AGN accretion disk act as a dynamo, which we show to follow from a modified Standard Model in which the magnetic torque of the dynamo replaces viscosity as the dominant mechanism accounting for angular momentum conservation during accretion. A black hole of mass M{sub BH} produces a steady dynamo voltage V {proportional_to} {radical}M{sub BH} giving V {approx} 10{sup 20} volts for M{sub BH} {approx} 10{sup 8} solar masses. The voltage V reappears as an inductive electric field at the advancing nose of a dynamo-driven jet, where plasma instability inherent in collisionless runaway acceleration allows ions to be steadily accelerated to energies {approx} V, finally ejected as cosmic rays. Transient events can produce much higher energies. The predicted disk radiation is similar to the Standard Model. Unique predictions concern the remarkable collimation of jets and emissions from the jet/radiolobe structure. Given MBH and the accretion rate, the model makes 7 predictions roughly consistent with data: (1) the jet length; (2) the jet radius; (3) the steady-state cosmic ray energy spectrum; (4) the maximum energy in this spectrum; (5) the UHE cosmic ray intensity on Earth; (6) electron synchrotron wavelengths; and (7) the power in synchrotron radiation. These qualitative successes motivate new computer simulations, experiments and data analysis to provide a quantitative verification of the model.

Fowler, T K; Colgate, S; Li, H; Bulmer, R H; Pino, J

2011-03-08T23:59:59.000Z

51

Phenomenology of Multi-W Processes in Cosmic Rays  

E-Print Network (OSTI)

We report on a study of the potential of various cosmic ray physics experiments to search for Standard Model processes involving the nonperturbative production of O(30) weak gauge bosons. Whereas present and near-future experiments are insensitive to proton-induced processes, neutrino-induced processes give rise to promising signatures and rates in AMANDA, DUMAND, MACRO and NESTOR provided that a cosmic neutrino flux exists at levels suggested by recent models of active galactic nuclei. The Fly's Eye currently constrains the largest region of parameter space characterizing multi-W phenomena.

D. A. Morris; A. Ringwald

1993-09-14T23:59:59.000Z

52

Cosmic Ray Signatures of Multi-W Processes  

E-Print Network (OSTI)

We explore the discovery potential of cosmic ray physics experiments for Standard Model processes involving the nonperturbative production of O(30) weak gauge bosons. We demonstrate an experimental insensitivity to proton-induced processes and emphasize the importance of neutrino-induced processes. The Fly's Eye currently constrains the largest region of parameter space characterizing multi-W phenomena if a cosmic neutrino flux exists at levels suggested by recent models of active galactic nuclei. MACRO (DUMAND) can constrain or observe additional regions by searching for 1-100 (1-10) characteristic near-vertical (near-horizontal) spatially compact energetic muon bundles per year.

D. A. Morris; A. Ringwald

1993-08-13T23:59:59.000Z

53

CMS Data Processing Workflows during an Extended Cosmic Ray Run  

Science Conference Proceedings (OSTI)

The CMS Collaboration conducted a month-long data taking exercise, the Cosmic Run At Four Tesla, during October-November 2008, with the goal of commissioning the experiment for extended operation. With all installed detector systems participating, CMS recorded 270 million cosmic ray events with the solenoid at a magnetic field strength of 3.8 T. This paper describes the data flow from the detector through the various online and offline computing systems, as well as the workflows used for recording the data, for aligning and calibrating the detector, and for analysis of the data.

Not Available

2009-11-01T23:59:59.000Z

54

Monte Carlo Simulations of Cosmic Rays Hadronic Interactions  

Science Conference Proceedings (OSTI)

This document describes the construction and results of the MaCoR software tool, developed to model the hadronic interactions of cosmic rays with different geometries of materials. The ubiquity of cosmic radiation in the environment results in the activation of stable isotopes, referred to as cosmogenic activities. The objective is to use this application in conjunction with a model of the MAJORANA DEMONSTRATOR components, from extraction to deployment, to evaluate cosmogenic activation of such components before and after deployment. The cosmic ray showers include several types of particles with a wide range of energy (MeV to GeV). It is infeasible to compute an exact result with a deterministic algorithm for this problem; Monte Carlo simulations are a more suitable approach to model cosmic ray hadronic interactions. In order to validate the results generated by the application, a test comparing experimental muon flux measurements and those predicted by the application is presented. The experimental and simulated results have a deviation of 3%.

Aguayo Navarrete, Estanislao; Orrell, John L.; Kouzes, Richard T.

2011-04-01T23:59:59.000Z

55

TRACING THE SOURCES OF COSMIC RAYS WITH MOLECULAR IONS  

Science Conference Proceedings (OSTI)

The rate of ionization by cosmic rays (CRs) in interstellar gas directly associated with {gamma}-ray-emitting supernova remnants (SNRs) is for the first time calculated to be several orders of magnitude larger than the Galactic average. Analysis of ionization-induced chemistry yields the first quantitative prediction of the astrophysical H{sup +} {sub 2} emission line spectrum, which should be detectable together with H{sup +} {sub 3} lines. The predicted coincident observation of those emission lines and {gamma}-rays will help prove that SNRs are sources of CRs.

Becker, Julia K.; Schuppan, Florian [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Theoretische Physik IV, D-44780 Bochum (Germany); Black, John H.; Mohammadtaher Safarzadeh, E-mail: julia@tp4.rub.de [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden)

2011-10-01T23:59:59.000Z

56

Cosmic-Ray Positrons: Are There Primary Sources?  

E-Print Network (OSTI)

Cosmic rays at the Earth include a secondary component originating in collisions of primary particles with the diffuse interstellar gas. The secondary cosmic rays are relatively rare but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, positrons and antiprotons. In addition, positrons and antiprotons may also come from unusual sources and possibly provide insight into new physics. For instance, the annihilation of heavy supersymmetric dark matter particles within the Galactic halo could lead to positrons or antiprotons with distinctive energy signatures. With the High-Energy Antimatter Telescope (HEAT) balloon-borne instrument, we have measured the abundances of positrons and electrons at energies between 1 and 50 GeV. The data suggest that indeed a small additional antimatter component may be present that cannot be explained by a purely secondary production mechanism. Here we describe the signature of the effect and discuss its possible origin.

Stephane Coutu; Steven W. Barwick; James J. Beatty; Amit Bhattacharyya; Chuck R. Bower; Christopher J. Chaput; Georgia A. de Nolfo; Michael A. DuVernois; Allan Labrador; Shawn P. McKee; Dietrich Muller; James A. Musser; Scott L. Nutter; Eric Schneider; Simon P. Swordy; Gregory Tarle; Andrew D. Tomasch; Eric Torbet

1999-02-10T23:59:59.000Z

57

A Fast Algorithm for Cosmic Rays Removal from Single Images  

E-Print Network (OSTI)

We present a method for detecting cosmic rays in single images. The algorithm is based on simple analysis of the histogram of the image data and does not use any modeling of the picture of the object. It does not require a good signal to noise ratio in the image data. Identification of multiple-pixel cosmic-ray hits is realized by running the procedure for detection and replacement iteratively. The tests performed by us, show that the method is very effective, when applied to the images with the spectroscopic data. It is also very fast in comparison with other single image algorithms found in astronomical data processing packages. Practical implementation and examples of application are presented.

Wojtek Pych

2003-11-12T23:59:59.000Z

58

Search for Correlated High Energy Cosmic Ray Events with CHICOS  

E-Print Network (OSTI)

We present the results of a search for time correlations in high energy cosmic ray data (primary E > 10^{14} eV) collected by the California HIgh school Cosmic ray ObServatory (CHICOS) array. Data from 60 detector sites spread over an area of 400 km^2 were studied for evidence of correlated events separated by more than 1 km with coincidence times ranging from 1 microsec up to 1 second. All searches were consistent with the absence of excess coincidences except for a 2.9 sigma excess observed for coincidence times less than 10 microsec. We report upper limits for the coincidence probability as a function of coincidence time.

Carlson, B E; Jillings, C J; Larson, M B; Lynn, T W; McKeown, R D; Hill, J E; Falkowski, B J; Seki, R; Sepikas, J; Yodh, G B; Hill, James E.

2005-01-01T23:59:59.000Z

59

Low Energy Cosmic Rays and the Disturbed Magnetosphere  

E-Print Network (OSTI)

Low energy galactic cosmic rays as well as particles accelerated to high energies either at the solar surface or in the interplanetary medium have access to the atmosphere above a given position on the Earth depending upon the state of the magnetosphere. The interpretation of the cosmic ray anisotropy, deduced from the neutron monitor (NM) network, must assume the variability of the magnetospheric configuration. Along with a short review of changes of the geomagnetic cutoffs in the disturbed magnetosphere reported in the earlier papers, we present the results of computations of transmissivity function and asymptotic directions for selected points on the ground and for a low altitude polar orbiting satellite as well. The computations, based on different available models of geomagnetic field of external sources are performed for quiet time periods and for strong geomagnetic disturbances occurred in 2003 and 2004.

Kudela, K

2013-01-01T23:59:59.000Z

60

Simulation of Cosmic Ray neutrinos Interactions in Water  

E-Print Network (OSTI)

The program CORSIKA, usually used to simulate extensive cosmic ray air showers, has been adapted to a water medium in order to study the acoustic detection of ultra high energy neutrinos. Showers in water from incident protons and from neutrinos have been generated and their properties are described. The results obtained from CORSIKA are compared to those from other available simulation programs such as Geant4.

T. Sloan

2006-09-21T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Milagro Contributions to XXVI International Cosmic Ray Conference  

SciTech Connect

Milagrito, a prototype for the Milagro detector, operated for 15 months in 1997--8 and collected 8.9 x 10{sup 9} events. It was the first extensive air shower (EAS) array sensitive to showers initiated by primaries with energy below 1 TeV. The shadows of the sun and moon observed with cosmic rays can be used to study systematic pointing shifts and measure the angular resolution of EAS arrays. Below a few TeV, the paths of cosmic rays coming toward the earth are bent by the helio- and geo-magnetic fields. This is expected to distort and displace the shadows of the sun and the moon. The moon shadow, offset from the nominal (unreflected) position, has been observed with high statistical significance in Milagrito. This can be used to establish energy calibrations, as well as to search for the anti-matter content of the VHE cosmic ray flux. The shadow of the sun has also been observed with high significance.

Hoffman, C.M.; Haines, T.J.; Sinnis, G.; Miller, R.S.; Thompson, N.T.

1999-08-01T23:59:59.000Z

62

Cosmic-ray Driven Outflows in Global Galaxy Disk Models  

E-Print Network (OSTI)

Galactic-scale winds are a generic feature of massive galaxies with high star formation rates across a broad range of redshifts. Despite their importance, a detailed physical understanding of what drives these mass-loaded global flows has remained elusive. In this paper, we explore the dynamical impact of cosmic rays by performing the first three-dimensional, adaptive mesh refinement simulations of an isolated starbursting galaxy that includes a basic model for the production, dynamics and diffusion of galactic cosmic rays. We find that including cosmic rays naturally leads to robust, massive, bipolar outflows from our 10^12 Msun halo, with a mass-loading factor Mout/SFR = 0.3 for our fiducial run. Other reasonable parameter choices led to mass-loading factors above unity. The wind is multiphase and is accelerated to velocities well in excess of the escape velocity. We employ a two-fluid model for the thermal gas and relativistic CR plasma and model a range of physics relevant to galaxy formation, including r...

Salem, Munier

2013-01-01T23:59:59.000Z

63

CAN ULTRAHIGH-ENERGY COSMIC RAYS COME FROM GAMMA-RAY BURSTS? COSMIC RAYS BELOW THE ANKLE AND GALACTIC GAMMA-RAY BURSTS  

SciTech Connect

The maximum cosmic-ray energy achievable by acceleration by a relativistic blast wave is derived. It is shown that forward shocks from long gamma-ray bursts (GRBs) in the interstellar medium accelerate protons to large enough energies, and have a sufficient energy budget, to produce the Galactic cosmic-ray component just below the ankle at 4 x 10{sup 18} eV, as per an earlier suggestion. It is further argued that, were extragalactic long GRBs responsible for the component above the ankle as well, the occasional Galactic GRB within the solar circle would contribute more than the observational limits on the outward flux from the solar circle, unless an avoidance scenario, such as intermittency and/or beaming, allows the present-day local flux to be less than 10{sup -3} of the average. Difficulties with these avoidance scenarios are noted.

Eichler, David [Physics Department, Ben-Gurion University, Be'er-Sheva 84105 (Israel); Pohl, Martin [Institut fuer Physik und Astronomie, Universitaet Potsdam, 14476 Potsdam-Golm (Germany)

2011-09-10T23:59:59.000Z

64

COSMIC-RAY AND X-RAY HEATING OF INTERSTELLAR CLOUDS AND PROTOPLANETARY DISKS  

SciTech Connect

Cosmic-ray and X-ray heating are derived from the electron energy-loss calculations of Dalgarno, Yan, and Liu for hydrogen-helium gas mixtures. These authors treated the heating from elastic scattering and collisional de-excitation of rotationally excited hydrogen molecules. Here we consider the heating that can arise from all ionization and excitation processes, with particular emphasis on the reactions of cosmic-ray and X-ray generated ions with the heavy neutral species, which we refer to as chemical heating. In molecular regions, chemical heating dominates and can account for 50% of the energy expended in the creation of an ion pair. The heating per ion pair ranges in the limit of negligible electron fraction from {approx}4.3 eV for diffuse atomic gas to {approx}13 eV for the moderately dense regions of molecular clouds and to {approx}18 eV for the very dense regions of protoplanetary disks. An important general conclusion of this study is that cosmic-ray and X-ray heating depends on the physical properties of the medium, i.e., on the molecular and electron fractions, the total density of hydrogen nuclei, and, to a lesser extent, on the temperature. It is also noted that chemical heating, the dominant process for cosmic-ray and X-ray heating, plays a role in UV irradiated molecular gas.

Glassgold, Alfred E. [Astronomy Department, University of California, Berkeley, CA 94720-3411 (United States); Galli, Daniele [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 (Italy); Padovani, Marco, E-mail: aglassgold@berkeley.edu, E-mail: galli@arcetri.astro.it, E-mail: marco.padovani@lra.ens.fr [Laboratoire de Radioastronomie Millimetrique, UMR 8112 du CNRS, Ecole Normale Superieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)

2012-09-10T23:59:59.000Z

65

Cosmic Rays from Supernovae Proven to Hit Earth | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Cosmic Rays from Supernovae Proven to Hit Earth Cosmic Rays from Supernovae Proven to Hit Earth Cosmic Rays from Supernovae Proven to Hit Earth March 5, 2013 - 4:40pm Addthis When stars explode, the supernovas send off shock waves like the one shown in this artist's rendition, which accelerate protons to cosmic-ray energies through a process known as Fermi acceleration. Andy Freeberg SLAC National Accelerator Laboratory Did you know? Protons make up 90 percent of the cosmic rays that hit Earth's atmosphere, triggering showers of particles that reach the ground and creating radiation for air travelers. The energies of these protons as they leave the supernovae are far beyond what the most powerful particle colliders on Earth can produce. Cosmic rays, energetic particles that pelt Earth, are born in the violent

66

The effect of highly structured cosmic magnetic fields on ultra-high energy cosmic ray propagation  

E-Print Network (OSTI)

The possibility that the magnetic field is strongly correlated with the large-scale structure of the universe has been recently considered in the literature. In this scenario the intergalactic magnetic field has a strong ($\\mu$G) regular component spanning tens of Mpc but localized in sheets and filaments, while the vast voids in between are almost free of magnetic field. If true, this could have important consequences on the propagation of ultra-high energy cosmic rays, and severely affect our capacity of doing astronomy with charged particles. A quantitative discussion of these effects is given in the present work.

Gustavo Medina Tanco

1998-08-07T23:59:59.000Z

67

A Method for Constraining Cosmic Magnetic Field Models Using Ultra-High Energy Cosmic Rays: The Field Scan Method  

E-Print Network (OSTI)

The Galactic magnetic field, locally observed to be on the order of a few $\\mu$G, is sufficiently strong to induce deflections in the arrival directions of ultra-high energy cosmic rays. We present a method that establishes measures of self-consistency for hypothesis sets comprised of cosmic magnetic field models and ultra-high energy cosmic ray composition and source distributions. The method uses two independent procedures to compare the backtracked velocity vectors outside the magnetic field model to the distribution of backtracked velocity directions of many isotropic observations with the same primary energies. This allows for an estimate of the statistical consistency between the observed data and simulated isotropic observations. Inconsistency with the isotropic expectation of source correlation in both procedures is interpreted as the hypothesis set providing a self-consistent description of GMF and UHECR properties for the cosmic ray observations.

Michael S. Sutherland; Brian M. Baughman; James J. Beatty

2012-07-06T23:59:59.000Z

68

The Pierre Auger Observatory II: Studies of Cosmic Ray Composition and Hadronic Interaction models  

E-Print Network (OSTI)

Studies of the composition of the highest energy cosmic rays with the Pierre Auger Observatory, including examination of hadronic physics effects on the structure of extensive air showers.

The Pierre Auger Collaboration; P. Abreu; M. Aglietta; E. J. Ahn; I. F. M. Albuquerque; D. Allard; I. Allekotte; J. Allen; P. Allison; J. Alvarez Castillo; J. Alvarez-Muñiz; M. Ambrosio; A. Aminaei; L. Anchordoqui; S. Andringa; T. Anti?i?; A. Anzalone; C. Aramo; E. Arganda; F. Arqueros; H. Asorey; P. Assis; J. Aublin; M. Ave; M. Avenier; G. Avila; T. Bäcker; M. Balzer; K. B. Barber; A. F. Barbosa; R. Bardenet; S. L. C. Barroso; B. Baughman; J. Bäuml; J. J. Beatty; B. R. Becker; K. H. Becker; A. Bellétoile; J. A. Bellido; S. BenZvi; C. Berat; X. Bertou; P. L. Biermann; P. Billoir; F. Blanco; M. Blanco; C. Bleve; H. Blümer; M. Bohá?ová; D. Boncioli; C. Bonifazi; R. Bonino; N. Borodai; J. Brack; P. Brogueira; W. C. Brown; R. Bruijn; P. Buchholz; A. Bueno; R. E. Burton; K. S. Caballero-Mora; L. Caramete; R. Caruso; A. Castellina; O. Catalano; G. Cataldi; L. Cazon; R. Cester; J. Chauvin; S. H. Cheng; A. Chiavassa; J. A. Chinellato; A. Chou; J. Chudoba; R. W. Clay; M. R. Coluccia; R. Conceição; F. Contreras; H. Cook; M. J. Cooper; J. Coppens; A. Cordier; U. Cotti; S. Coutu; C. E. Covault; A. Creusot; A. Criss; J. Cronin; A. Curutiu; S. Dagoret-Campagne; R. Dallier; S. Dasso; K. Daumiller; B. R. Dawson; R. M. de Almeida; M. De Domenico; C. De Donato; S. J. de Jong; G. De La Vega; W. J. M. de Mello Junior; J. R. T. de Mello Neto; I. De Mitri; V. de Souza; K. D. de Vries; G. Decerprit; L. del Peral; O. Deligny; H. Dembinski; N. Dhital; C. Di Giulio; J. C. Diaz; M. L. Díaz Castro; P. N. Diep; C. Dobrigkeit; W. Docters; J. C. D'Olivo; P. N. Dong; A. Dorofeev; J. C. dos Anjos; M. T. Dova; D. D'Urso; I. Dutan; J. Ebr; R. Engel; M. Erdmann; C. O. Escobar; A. Etchegoyen; P. Facal San Luis; I. Fajardo Tapia; H. Falcke; G. Farrar; A. C. Fauth; N. Fazzini; A. P. Ferguson; A. Ferrero; B. Fick; A. Filevich; A. Filip?i?; S. Fliescher; C. E. Fracchiolla; E. D. Fraenkel; U. Fröhlich; B. Fuchs; R. Gaior; R. F. Gamarra; S. Gambetta; B. García; D. García Gámez; D. Garcia-Pinto; A. Gascon; H. Gemmeke; K. Gesterling; P. L. Ghia; U. Giaccari; M. Giller; H. Glass; M. S. Gold; G. Golup; F. Gomez Albarracin; M. Gómez Berisso; P. Gonçalves; D. Gonzalez; J. G. Gonzalez; B. Gookin; D. Góra; A. Gorgi; P. Gouffon; S. R. Gozzini; E. Grashorn; S. Grebe; N. Griffith; M. Grigat; A. F. Grillo; Y. Guardincerri; F. Guarino; G. P. Guedes; A. Guzman; J. D. Hague; P. Hansen; D. Harari; S. Harmsma; J. L. Harton; A. Haungs; T. Hebbeker; D. Heck; A. E. Herve; C. Hojvat; N. Hollon; V. C. Holmes; P. Homola; J. R. Hörandel; A. Horneffer; M. Hrabovský; T. Huege; A. Insolia; F. Ionita; A. Italiano; C. Jarne; S. Jiraskova; M. Josebachuili; K. Kadija; K. -H. Kampert; P. Karhan; P. Kasper; B. Kégl; B. Keilhauer; A. Keivani; J. L. Kelley; E. Kemp; R. M. Kieckhafer; H. O. Klages; M. Kleifges; J. Kleinfeller; J. Knapp; D. -H. Koang; K. Kotera; N. Krohm; O. Krömer; D. Kruppke-Hansen; F. Kuehn; D. Kuempel; J. K. Kulbartz; N. Kunka; G. La Rosa; C. Lachaud; P. Lautridou; M. S. A. B. Leão; D. Lebrun; P. Lebrun; M. A. Leigui de Oliveira; A. Lemiere; A. Letessier-Selvon; I. Lhenry-Yvon; K. Link; R. López; A. Lopez Agüera; K. Louedec; J. Lozano Bahilo; A. Lucero; M. Ludwig; H. Lyberis; M. C. Maccarone; C. Macolino; S. Maldera; D. Mandat; P. Mantsch; A. G. Mariazzi; J. Marin; V. Marin; I. C. Maris; H. R. Marquez Falcon; G. Marsella; D. Martello; L. Martin; H. Martinez; O. Martínez Bravo; H. J. Mathes; J. Matthews; J. A. J. Matthews; G. Matthiae; D. Maurizio; P. O. Mazur; G. Medina-Tanco; M. Melissas; D. Melo; E. Menichetti; A. Menshikov; P. Mertsch; C. Meurer; S. Mi?anovi?; M. I. Micheletti; W. Miller; L. Miramonti; S. Mollerach; M. Monasor; D. Monnier Ragaigne; F. Montanet; B. Morales; C. Morello; E. Moreno; J. C. Moreno; C. Morris; M. Mostafá; C. A. Moura; S. Mueller; M. A. Muller; G. Müller; M. Münchmeyer; R. Mussa; G. Navarra; J. L. Navarro; S. Navas; P. Necesal; L. Nellen; A. Nelles; J. Neuser; P. T. Nhung; L. Niemietz; N. Nierstenhoefer; D. Nitz; D. Nosek; L. Nožka; M. Nyklicek; J. Oehlschläger; A. Olinto; V. M. Olmos-Gilbaja; M. Ortiz; N. Pacheco; D. Pakk Selmi-Dei; M. Palatka; J. Pallotta; N. Palmieri; G. Parente; E. Parizot; A. Parra; R. D. Parsons; S. Pastor; T. Paul; M. Pech; J. P?kala; R. Pelayo; I. M. Pepe; L. Perrone; R. Pesce; E. Petermann; S. Petrera; P. Petrinca; A. Petrolini; Y. Petrov; J. Petrovic; C. Pfendner; N. Phan; R. Piegaia; T. Pierog; P. Pieroni; M. Pimenta; V. Pirronello; M. Platino; V. H. Ponce; M. Pontz; P. Privitera; M. Prouza; E. J. Quel; S. Querchfeld; J. Rautenberg; O. Ravel; D. Ravignani; B. Revenu; J. Ridky; S. Riggi; M. Risse; P. Ristori; H. Rivera; V. Rizi; J. Roberts; C. Robledo; W. Rodrigues de Carvalho; G. Rodriguez; J. Rodriguez Martino; J. Rodriguez Rojo; I. Rodriguez-Cabo; M. D. Rodríguez-Frías; G. Ros; J. Rosado

2011-07-24T23:59:59.000Z

69

30TH INTERNATIONAL COSMIC RAY CONFERENCE The VERITAS Trigger System  

E-Print Network (OSTI)

Abstract: The VERITAS gamma-ray observatory, situated in southern Arizona, is an array of four 12m diameter imaging Cherenkov telescopes, each with a 499-pixel photomultiplier-tube camera. The instrument is designed to detect astrophysical gamma rays at energies above 100 GeV. At the low end of the VERITAS energy range, fluctuations in the night sky background light and single muons from cosmic-ray showers constitute significant backgrounds. VERITAS employs a three-tier trigger system to reduce the rate of these background events: an initial trigger which acts at the single pixel level, a pattern trigger which acts on the relative timing and distribution of pixel-level triggers within a single telescope camera, and an array-level trigger which requires simultaneous observation of an air-shower event in multiple telescopes. This final coincidence requirement significantly reduces the rate of background events, particularly those due to single muons. In this paper, the implementation of all levels of the VERITAS trigger system is discussed and their joint performance is characterized. The VERITAS gamma-ray observatory, situated in southern Arizona, is an array of four 12m diameter imaging Cherenkov telescopes, each with a 499pixel photomultiplier-tube camera. The instrument is designed to detect astrophysical gamma rays with energies above 100 GeV. At the low end of the VERITAS energy range, fluctuations in the night sky background light (NSB) and single muons from cosmic-ray showers constitute significant backgrounds, which the three-tiered VERI-TAS trigger system is designed to reduce. VERITAS has operated in a three-telescope configuration with the full trigger system since December 2006. A fourth telescope was added to the array in

A. Weinstein; For The; Veritas Collaboration

2007-01-01T23:59:59.000Z

70

GZK Photons as Ultra High Energy Cosmic Rays  

E-Print Network (OSTI)

We calculate the flux of "GZK-photons", namely the flux of Ultra High Energy Cosmic Rays (UHECR) consisting of photons produced by extragalactic nucleons through the resonant photoproduction of pions, the so called GZK effect. We We calculate the flux of "GZK-photons", namely the flux of Ultra High Energy Cosmic Rays (UHECR) consisting of photons produced by extragalactic nucleons through the resonant photoproduction of pions, the so called GZK effect. We show that, for primary nucleons, the GZK photon fraction of the total UHECR flux is between $10^{-4}$ and $10^{-2}$ above $10^{19}$ eV and up to the order of 0.1 above $10^{20}$ eV. The GZK photon flux depends on the assumed UHECR spectrum, slope of the nucleon flux at the source, distribution of sources and intervening backgrounds. Detection of this photon flux would open the way for UHECR gamma-ray astronomy. Detection of a larger photon flux would imply the emission of photons at the source or new physics. We compare the photon fractions expected for GZK photons and the minimal predicted by Top-Down models. We find that the photon fraction above $10^{19}$ eV is a crucial test for Top-Down models.

Graciela B. Gelmini; Oleg E. Kalashev; Dmitry V. Semikoz

2005-06-06T23:59:59.000Z

71

The Composition of Cosmic Rays at the Knee  

E-Print Network (OSTI)

The observation of a small change in spectral slope, or ’knee ’ in the fluxes of cosmic rays near energies 10 15 eV has caused much speculation since its discovery over 40 years ago. The origin of this feature remains unknown. A small workshop to review some modern experimental measurements of this region was held at the Adler Planetarium in Chicago, USA in June 2000. This paper summarizes the results presented at this workshop and the discussion of their interpretation in the context of hadronic models of atmospheric airshowers.

S. P. Swordy; L. F. Fortson; El A; C. L. Pryke; T. Shibata; S. P. Wakely; Z. Cao; M. L. Cherry; S. Coutu; J. Cronin; R. Engel; J. W. Fowler; S. A. Minnick; A. Moiseev; D. Muller; M. Roth; A. Sill; G. Spiczak H

2002-01-01T23:59:59.000Z

72

The Composition of Cosmic Rays at the Knee  

E-Print Network (OSTI)

The observation of a small change in spectral slope, or 'knee' in the fluxes of cosmic rays near energies 10^15 eV has caused much speculation since its discovery over 40 years ago. The origin of this feature remains unknown. A small workshop to review some modern experimental measurements of this region was held at the Adler Planetarium in Chicago, USA in June 2000. This paper summarizes the results presented at this workshop and the discussion of their interpretation in the context of hadronic models of atmospheric airshowers.

S. P. Swordy; L. F. Fortson; J. Hinton; J. Horandel; J. Knapp; C. L. Pryke; T. Shibata; S. P. Wakely; Z. Cao; M. L. Cherry; S. Coutu; J. Cronin; R. Engel; J. W. Fowler; K. - H. Kampert; J. Kettler; D. B. Kieda; J. Matthews; S. A. Minnick; A. Moiseev; D. Muller; M. Roth; A. Sill; G. Spiczak

2002-02-07T23:59:59.000Z

73

Cosmic Ray Positrons at High Energies: A New Measurement  

E-Print Network (OSTI)

We present a new measurement of the cosmic-ray positron fraction e+/(e+ + e-) obtained from the first balloon flight of the High Energy Antimatter Telescope (HEAT). Using a magnet spectrometer combined with a transition radiation detector, an electromagnetic calorimeter, and time-of-flight counters we have achieved a high degree of background rejection. Our results do not indicate a major contribution to the positron flux from primary sources. In particular, we see no evidence for the significant rise in the positron fraction at energies above ~10 GeV previously reported.

HEAT Collaboration

1995-05-30T23:59:59.000Z

74

Gamma-Ray Bursts and Quantum Cosmic Censorship  

E-Print Network (OSTI)

Gamma-ray bursts are believed to result from the coalescence of binary neutron stars. However, the standard proposals for conversion of the gravitational energy to thermal energy have difficulties. We show that if the merger of the two neutron stars results in a naked singularity, instead of a black hole, the ensuing quantum particle creation can provide the requisite thermal energy in a straightforward way. The back-reaction of the created particles can avoid the formation of the naked singularity predicted by the classical theory. Hence cosmic censorship holds in the quantum theory, even if it were to be violated in classical general relativity.

T. P. Singh

1998-05-17T23:59:59.000Z

75

ENERGY SPECTRA OF COSMIC-RAY NUCLEI AT HIGH ENERGIES  

SciTech Connect

We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment Cosmic-Ray Energetics And Mass (CREAM). The instrument included different particle detectors to provide redundant charge identification and measure the energy of CRs up to several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg, Si, and Fe are presented up to approx10{sup 14} eV. The spectral shape looks nearly the same for these primary elements and it can be fitted to an E {sup -2.66} {sup +}- {sup 0.04} power law in energy. Moreover, a new measurement of the absolute intensity of nitrogen in the 100-800 GeV/n energy range with smaller errors than previous observations, clearly indicates a hardening of the spectrum at high energy. The relative abundance of N/O at the top of the atmosphere is measured to be 0.080 +- 0.025 (stat.)+-0.025 (sys.) at approx800 GeV/n, in good agreement with a recent result from the first CREAM flight.

Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Malinine, A. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Allison, P.; Beatty, J. J.; Brandt, T. J. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States); Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S. [Department of Physics, University of Siena and INFN, Via Roma 56, 53100 Siena (Italy); Barbier, L. [Astroparticle Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Childers, J. T.; DuVernois, M. A. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Conklin, N. B.; Coutu, S. [Department of Physics, Penn State University, University Park, PA 16802 (United States); Jeon, J. A. [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Minnick, S., E-mail: paolo.maestro@pi.infn.i [Department of Physics, Kent State University, Tuscarawas, New Philadelphia, OH 44663 (United States)

2009-12-10T23:59:59.000Z

76

THE DISCOVERY OF GEOMAGNETICALLY TRAPPED COSMIC-RAY ANTIPROTONS  

Science Conference Proceedings (OSTI)

The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60-750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the sub-cutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.

Adriani, O. [Department of Physics, University of Florence, I-50019 Sesto Fiorentino, Florence (Italy); Barbarino, G. C. [Department of Physics, University of Naples 'Federico II', I-80126 Naples (Italy); Bazilevskaya, G. A. [Lebedev Physical Institute, RU-119991, Moscow (Russian Federation); Bellotti, R.; Bruno, A.; Cafagna, F. [Department of Physics, University of Bari, I-70126 Bari (Italy); Boezio, M.; Bonvicini, V. [INFN, Sezione di Trieste, I-34149 Trieste (Italy); Bogomolov, E. A. [Ioffe Physical Technical Institute, RU-194021 St. Petersburg (Russian Federation); Bongi, M.; Bottai, S. [INFN, Sezione di Florence, I-50019 Sesto Fiorentino, Florence (Italy); Borisov, S.; Casolino, M.; De Pascale, M. P.; De Santis, C. [INFN, Sezione di Rome 'Tor Vergata', I-00133 Rome (Italy); Campana, D.; Carbone, R.; Consiglio, L. [INFN, Sezione di Naples, I-80126 Naples (Italy); Carlson, P. [KTH, Department of Physics, and the Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Centre, SE-10691 Stockholm (Sweden); Castellini, G., E-mail: alessandro.bruno@ba.infn.it [IFAC, I-50019 Sesto Fiorentino, Florence (Italy)

2011-08-20T23:59:59.000Z

77

The discovery of geomagnetically trapped cosmic ray antiprotons  

E-Print Network (OSTI)

The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60--750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the sub-cutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.

O. Adriani; G. C. Barbarino; G. A. Bazilevskaya; R. Bellotti; M. Boezio; E. A. Bogomolov; M. Bongi; V. Bonvicini; S. Borisov; S. Bottai; A. Bruno; F. Cafagna; D. Campana; R. Carbone; P. Carlson; M. Casolino; G. Castellini; L. Consiglio; M. P. De Pascale; C. De Santis; N. De Simone; V. Di Felice; A. M. Galper; W. Gillard; L. Grishantseva; G. Jerse; A. V. Karelin; M. D. Kheymits; S. V. Koldashov; S. Y. Krutkov; A. N. Kvashnin; A. Leonov; V. Malakhov; L. Marcelli; A. G. Mayorov; W. Menn; V. V. Mikhailov; E. Mocchiutti; A. Monaco; N. Mori; N. Nikonov; G. Osteria; F. Palma; P. Papini; M. Pearce; P. Picozza; C. Pizzolotto; M. Ricci; S. B. Ricciarini; L. Rossetto; R. Sarkar; M. Simon; R. Sparvoli; P. Spillantini; Y. I. Stozhkov; A. Vacchi; E. Vannuccini; G. Vasilyev; S. A. Voronov; Y. T. Yurkin; J. Wu; G. Zampa; N. Zampa; V. G. Zverev

2011-07-25T23:59:59.000Z

78

Ultra High Energy Particles Propagation and the Transition from Galactic to Extra-Galactic Cosmic Rays  

E-Print Network (OSTI)

We discuss the basic features of the propagation of Ultra High Energy Cosmic Rays in astrophysical backgrounds, comparing two alternative computation schemes to compute the expected fluxes. We also discuss the issue of the transition among galactic and extra-galactic cosmic rays using theoretical results on fluxes to compare different models.

Aloisio, Roberto

2013-01-01T23:59:59.000Z

79

The Effect of Atmospheric Water Vapor on Neutron Count in the Cosmic-Ray Soil Moisture Observing System  

Science Conference Proceedings (OSTI)

The cosmic-ray method for measuring soil moisture, used in the COsmic-ray Soil Moisture Observing System (COSMOS), relies on the exceptional ability of hydrogen to moderate fast neutrons. Sources of hydrogen near the ground, other than soil ...

R. Rosolem; W. J. Shuttleworth; M. Zreda; T. E. Franz; X. Zeng; S. A. Kurc

80

The Effect of Atmospheric Water Vapor on Neutron Count in the Cosmic-Ray Soil Moisture Observing System  

Science Conference Proceedings (OSTI)

The cosmic-ray method for measuring soil moisture, used in the Cosmic-Ray Soil Moisture Observing System (COSMOS), relies on the exceptional ability of hydrogen to moderate fast neutrons. Sources of hydrogen near the ground, other than soil ...

R. Rosolem; W. J. Shuttleworth; M. Zreda; T. E. Franz; X. Zeng; S. A. Kurc

2013-10-01T23:59:59.000Z

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81

Gamma Ray Bursts: recent results and connections to very high energy Cosmic Rays and Neutrinos  

E-Print Network (OSTI)

Gamma-ray bursts are the most concentrated explosions in the Universe. They have been detected electromagnetically at energies up to tens of GeV, and it is suspected that they could be active at least up to TeV energies. It is also speculated that they could emit cosmic rays and neutrinos at energies reaching up to the $10^{18}-10^{20}$ eV range. Here we review the recent developments in the photon phenomenology in the light of \\swift and \\fermi satellite observations, as well as recent IceCube upper limits on their neutrino luminosity. We discuss some of the theoretical models developed to explain these observations and their possible contribution to a very high energy cosmic ray and neutrino background.

Péter Mészáros; Katsuaki Asano; Péter Veres

2012-09-11T23:59:59.000Z

82

Amplified radio emission from cosmic ray air showers in thunderstorms  

E-Print Network (OSTI)

Cosmic ray air showers produce radio emission, consisting in large part of geosynchrotron emission. Since the radiation mechanism is based on particle acceleration, the atmospheric electric field can play an important role. Especially inside thunderclouds large electric fields can be present. We examine the contribution of an electric field to the emission mechanism theoretically and experimentally. Two mechanisms of amplification of radio emission are considered: the acceleration radiation of the shower particles and the radiation from the current that is produced by ionization electrons moving in the electric field. We selected and evaluated LOPES data recorded during thunderstorms, periods of heavy cloudiness and periods of cloudless weather. We find that during thunderstorms the radio emission can be strongly enhanced. No amplified pulses were found during periods of cloudless sky or heavy cloudiness, suggesting that the electric field effect for radio air shower measurements can be safely ignored during non-thunderstorm conditions.

Stijn Buitink; for the LOPES collaboration

2007-02-16T23:59:59.000Z

83

Cosmic Gamma-Ray Bursts The Remaining Mysteries  

E-Print Network (OSTI)

To anyone who has read a scientific journal or even a newspaper in the last six months, it might appear that cosmic gamma-ray bursts hold no more mysteries: they are cosmological, and possibly the most powerful explosions in the Universe. In fact, however, bursts remain mysterious in many ways. There is no general agreement upon the nature of the event which releases the initial energy. One burst at least appears to strain the energy budget of the merging neutron star model. There is evidence that another recent event may have come from a nearby supernova. Finally, while the number count statistics clearly show a strong deviation from the -3/2 power law expected for a Euclidean, homogeneous distribution, the distributions of some classes of bursts appear to follow a -3/2 power law rather closely. The recent data on bursts is reviewed, some of the mysteries discussed, and future experiments are outlined.

Hurley, K

1998-01-01T23:59:59.000Z

84

Commissioning of the ATLAS Muon Spectrometer with Cosmic Rays  

E-Print Network (OSTI)

The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.

The ATLAS Collaboration

2010-06-22T23:59:59.000Z

85

Cosmic Ray Anomalies Inspired Some Discussion on Modified Chaplygin Gas  

E-Print Network (OSTI)

The postulation of Dark energy and Dark matter on the basis of observational results does not end the mystery of their existence. Theoretically new insights into dark matter have been achieved analyzing recent experimental data from the cosmic ray physics. It has been shown that, if the dark matter is a hidden scalar field, then it is not only possible to explain the ATIC/PPB BETS excess but also the observed dark matter abundance naturally and simultaneously. Being motivated, mainly by the assumption of hidden scalar field and some associated works, we consider the Modified Chaplygin Gas for some thermodynamical analysis. The point that if the scalar field is assumed to oscillate before the reheating was not completed, i.e., T_R importance of thermodynamical analysis. We, assuming the properties of Modified Chaplygin Gas, derive an expression for the second law of thermodynamics. It is obse...

Saikia, Julie

2009-01-01T23:59:59.000Z

86

Cosmic Ray Anomalies Inspired Some Discussion on Modified Chaplygin Gas  

E-Print Network (OSTI)

The postulation of Dark energy and Dark matter on the basis of observational results does not end the mystery of their existence. Theoretically new insights into dark matter have been achieved analyzing recent experimental data from the cosmic ray physics. It has been shown that, if the dark matter is a hidden scalar field, then it is not only possible to explain the ATIC/PPB BETS excess but also the observed dark matter abundance naturally and simultaneously. Being motivated, mainly by the assumption of hidden scalar field and some associated works, we consider the Modified Chaplygin Gas for some thermodynamical analysis. The point that if the scalar field is assumed to oscillate before the reheating was not completed, i.e., T_R importance of thermodynamical analysis. We, assuming the properties of Modified Chaplygin Gas, derive an expression for the second law of thermodynamics. It is observed that it also sheds some new lights on Generalised Second Law.

Julie Saikia; Balendra Kr. Dev Choudhury

2009-06-03T23:59:59.000Z

87

Cosmic ray physics in calculations of cosmological structure formation  

E-Print Network (OSTI)

Cosmic rays (CRs) play a decisive role within our own Galaxy. They provide partial pressure support against gravity, they trace past energetic events such as supernovae, and they reveal the underlying structure of the baryonic matter distribution through their interactions. To study the impact of CRs on galaxy and cosmic structure formation and evolution, we develop an approximative framework for treating dynamical and radiative effects of CRs in cosmological simulations. Our guiding principle is to try to find a balance between capturing as many physical properties of CR populations as possible while at the same time requiring as little extra computational resources as possible. We approximate the CR spectrum of each fluid element by a single power-law, with spatially and temporally varying normalisation, low-energy cut-off, and spectral index. Principles of conservation of particle number, energy, and pressure are then used to derive evolution equations for the basic variables describing the CR spectrum, both due to adiabatic and non-adiabatic processes. The processes considered include compression and rarefaction, CR injection via shocks in supernova remnants, injection in structure formation shock waves, in-situ re-acceleration of CRs, CR spatial diffusion, CR energy losses due to Coulomb interactions, ionisation losses, Bremsstrahlung losses, and, finally, hadronic interactions with the background gas, including the associated gamma-ray and radio emission due to subsequent pion decay. We show that the formalism reproduces CR energy densities, pressure, and cooling rates with an accuracy of ~10% in steady state conditions where CR injection balances cooling. Our framework is therefore well suited to be included into numerical simulation schemes of galaxy and structure formation. (abridged)

Torsten A. Ensslin; Christoph Pfrommer; Volker Springel; Martin Jubelgas

2006-03-17T23:59:59.000Z

88

Possible association of ultra-high-energy cosmic-ray events with strong gamma-ray bursts  

E-Print Network (OSTI)

We point out that each of the error boxes of the two highest-energy cosmic-ray shower events known, overlaps with that of a strong gamma-ray burst (GRB). The GRBs precede the cosmic rays by 5.5, and 11 months respectively. In one case the strongest known cosmic ray is paired with the strongest gamma-ray burst in the BATSE catalogue. The probability of this to have occurred by chance seems rather small. Without building on post-factum statistics, we think the above is remarkable enough to suggest that the cosmic ray and gamma-ray burst were produced by the same outburst. A time delay (and a small positional disparity) is expected, since the trajectory of a charged cosmic-ray particle is wriggled by intervening magnetic fields. We estimate that the Galaxy's field alone may produce a delay of the order observed. We discuss some of the implications that follow if such an association is confirmed. For example, the upper limit on the distance to the cosmic-ray source, combined with a much-better-determined position of the gamma-ray burst source, narrows greatly the volume in which to look for an optical counterpart. There is also useful information in the time delay regarding, e.g., intergalactic magnetic fields.

Mordehai Milgrom; Vladimir Usov

1995-05-03T23:59:59.000Z

89

NONTHERMAL RADIATION FROM COSMIC-RAY MODIFIED SHOCKS  

Science Conference Proceedings (OSTI)

We calculate nonthermal radiation from cosmic-ray (CR) protons and electrons accelerated at CR modified plane and spherical shocks, using time-dependent, diffusive shock acceleration (DSA) simulations that include radiative losses of CR electrons. Strong non-relativistic shocks with physical parameters relevant for young supernova remnants (SNRs) are considered in both the plane-parallel and spherically symmetric geometries, and compared at times when their dynamical and CR properties are concordant. A thermal leakage injection model and a Bohm-like diffusion coefficient are adopted. After DSA energy gains balance radiative losses, the electron spectrum at the plane shock approaches a time-asymptotic spectrum with a super-exponential cutoff above the equilibrium momentum. The postshock electron spectrum cuts off at a progressively lower momentum downstream from the shock due to the energy losses. That results in the steepening of the volume integrated electron energy spectrum by one power of the particle energy. These features evolve toward lower energies in the spherical, SNR shocks. In a CR modified shock, pion decay gamma-ray emission reveals distinct signatures of nonlinear DSA due to the concave proton momentum spectrum. Although the electron momentum spectrum has a much weaker concavity, the synchrotron spectral slope at the shock may flatten by about 0.1-0.3 between radio and X-ray bands. The slope of the volume integrated emission spectrum behaves nonlinearly around the break frequency.

Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Edmon, Paul P. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Jones, T. W., E-mail: kang@uju.es.pusan.ac.kr, E-mail: pedmon@physics.umanitoba.ca, E-mail: twj@msi.umn.edu [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2012-02-01T23:59:59.000Z

90

30TH INTERNATIONAL COSMIC RAY CONFERENCE Search for Gamma Ray Bursts using the single particle technique at the Pierre Auger  

E-Print Network (OSTI)

30TH INTERNATIONAL COSMIC RAY CONFERENCE Search for Gamma Ray Bursts using the single particle by satellites. Introduction Since their discovery at the end of the 60s[1], Gamma Ray Bursts (GRB) have been of high in- terest to astrophysics. A GRB is characterised by a sudden emission of gamma rays during

Hörandel, Jörg R.

91

Ultra high energy cosmic rays and the large scale structure of the galactic magnetic field  

E-Print Network (OSTI)

We study the deflection of ultra high energy cosmic ray protons in different models of the regular galactic magnetic field. Such particles have gyroradii well in excess of 1 kpc and their propagation in the galaxy reflects only the large scale structure of the galactic magnetic field. A future large experimental statistics of cosmic rays of energy above 10$^{19}$ eV could be used for a study of the large scale structure of the galactic magnetic field if such cosmic rays are indeed charged nuclei accelerated at powerful astrophysical objects and if the distribution of their sources is not fully isotropic.

Todor Stanev

1996-07-17T23:59:59.000Z

92

MAGNETIC AND DENSITY SPIKES IN COSMIC-RAY SHOCK PRECURSORS  

Science Conference Proceedings (OSTI)

In shock precursors populated by accelerated cosmic rays (CRs), the CR return current instability is believed to significantly enhance the pre-shock perturbations of magnetic field. We have obtained fully nonlinear exact ideal MHD solutions supported by the CR return current. The solutions occur as localized spikes of circularly polarized Alfven envelopes (solitons or breathers). As the conventional (undriven) solitons, the obtained magnetic spikes propagate at a speed C proportional to their amplitude, C=C{sub A}B{sub max}/{radical}2B{sub 0}. The sufficiently strong solitons run thus ahead of the main shock and stand in the precursor, being supported by the return current. This property of the nonlinear solutions is strikingly different from the linear theory that predicts non-propagating (that is, convected downstream) circularly polarized waves. The nonlinear solutions may come either in isolated pulses (solitons) or in soliton-trains (cnoidal waves). The morphological similarity of such quasi-periodic soliton chains with recently observed X-ray stripes in the Tycho supernova remnant (SNR) is briefly discussed. The magnetic field amplification determined by the suggested saturation process is obtained as a function of decreasing SNR blast wave velocity during its evolution from the ejecta dominated to the Sedov-Taylor stage.

Malkov, M. A.; Diamond, P. H. [CASS and Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Sagdeev, R. Z., E-mail: mmalkov@ucsd.edu [Department of Physics, University of Maryland, College Park, MD 20742-3280 (United States)

2012-04-01T23:59:59.000Z

93

The relation between post-shock temperature, cosmic-ray pressure and cosmic-ray escape for non-relativistic shocks  

E-Print Network (OSTI)

Supernova remnants are thought to be the dominant source of Galactic cosmic rays. This requires that at least 5% of the available energy is transferred to cosmic rays, implying a high cosmic-ray pressure downstream of supernova remnant shocks. Recently, it has been shown that the downstream temperature in some remnants is low compared to the measured shock velocities, implying that additional pressure support by accelerated particles is present. Here we use a two-fluid thermodynamic approach to derive the relation between post-shock fractional cosmic-ray pressure and post-shock temperature, assuming no additional heating beyond adiabatic heating in the shock precursor and with all non-adiabatic heating occurring at the subshock. The derived relations show that a high fractional cosmic-ray pressure is only possible, if a substantial fraction of the incoming energy flux escapes from the system. Recently a shock velocity and a downstream proton temperature was measured for a shock in the supernova remnant RCW 86...

Vink, Jacco; Helder, E A; Schure, K M

2010-01-01T23:59:59.000Z

94

X-ray imaging, spacecraft nuclear fission and cosmic ray contraband  

NLE Websites -- All DOE Office Websites (Extended Search)

R&D 100 Awards winners R&D 100 Awards winners X-ray imaging, spacecraft nuclear fission and cosmic ray contraband detection score R&D 100 awards R&D Magazine announced the winners and three technologies from Los Alamos National Laboratory and its partners are among the honorees. July 8, 2013 MiniMAX is a battery powered, digital x-ray imaging system that is completely self-contained, lightweight, compact and portable. MiniMAX is a battery powered, digital x-ray imaging system that is completely self-contained, lightweight, compact and portable. Contact Nancy Ambrosiano Communications Office (505) 667-0471 Email "The innovation and creativity shown in this year's awards is truly inspiring. It gives me great confidence in the Laboratory's intellectual vitality and ongoing role in national security science. Congratulations to

95

PSU-PAL-99-1 Cosmic-Ray Positrons: Are There Primary Sources?  

E-Print Network (OSTI)

Galactic cosmic rays consist of primary and secondary particles. Primary cosmic rays are thought to be energized by first order Fermi acceleration processes at supernova shock fronts within our Galaxy. The cosmic rays that eventually reach the Earth from this source are mainly protons and atomic nuclei, but also include electrons. Secondary cosmic rays are created in collisions of primary particles with the diffuse interstellar gas. They are relatively rare but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, positrons and antiprotons. In addition, positrons and antiprotons may also come from unusual sources and possibly provide insight into new physics. For instance, the annihilation of heavy supersymmetric dark matter particles within the Galactic halo could lead to positrons or antiprotons with distinctive energy signatures. With the High-Energy

Stéphane Coutu; Steven W. Barwick; James J. Beatty; Amit Bhattacharyya; R. Bower; Christopher J. Chaput; Georgia A. De Nolfo; Michael A. Duvernois; Shawn P. Mckee; Dietrich Müller; James A. Musser; Scott L. Nutter; Simon P. Swordy; Gregory Tarlé; Andrew D. Tomasch; Eric Torbet

1999-01-01T23:59:59.000Z

96

Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays: Results from AMS-01  

E-Print Network (OSTI)

Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the ...

Becker, R.

97

Search for microquasar features in cosmic ray spectra with AMS-01  

E-Print Network (OSTI)

Accreting x-ray binaries are sometimes observed to emit compact, relativistic jets of cool plasma; these objects are called "microquasars". It is possible that these jets are responsible for a large flux of galactic cosmic ...

Monreal, Benjamin, 1977-

2004-01-01T23:59:59.000Z

98

Search for antideuterons and strangelets in cosmic rays with AMS-01  

E-Print Network (OSTI)

AMS (the Alpha Magnetic Spectrometer) is a high-energy particle detector in space. An engineer- ing version of AMS, AMS-01, flew on the space shuttle Discovery for ten days in June 1998 and collected 108 cosmic ray events. ...

Henning, Reyco, 1975-

2004-01-01T23:59:59.000Z

99

Solar Activity and Cloud Opacity Variations: A Modulated Cosmic Ray Ionization Model  

Science Conference Proceedings (OSTI)

The observed correlation between global low cloud amount and the flux of high energy cosmic rays supports the idea that ionization plays a crucial role in tropospheric cloud formation. This idea is explored quantitatively with a simple model ...

David Marsden; Richard E. Lingenfelter

2003-02-01T23:59:59.000Z

100

Pierre Auger Enhancements: Transition from Galactic to Extragalactic Cosmic Ray Sources  

SciTech Connect

The Pierre Auger Collaboration has decided to include detector enhancements in order to have unitary detection efficiencies down to 1017 eV in cosmic rays detection. These enhancements consist in high elevation telescopes and an infill area with both surface detectors and underground muon counters thus allowing a detailed study of the spectrum region where the cosmic rays sources are assumed to change from galactic to extragalactic origins.

Etchegoyen, A. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Universidad Tecnologica Nacional, Regional Buenos Aires, Buenos Aires (Argentina); Melo, D.; Supanitsky, A. D. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Medina, M. C. [Laboratorio Tandar - Comision Nacional de Energia Atomica, Buenos Aires (Argentina); CONICET. Buenos Aires (Argentina)

2007-06-19T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Commissioning of the ATLAS Level-1 Trigger with Cosmic Rays  

E-Print Network (OSTI)

The ATLAS detector at CERN's Large Hadron Collider will be exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system was designed to select potentially interesting events and reduce the incoming rate to 100-200 Hz. The first trigger level (LVL1) is implemented in custom-built electronics, the second and third trigger levels are realized in software. Based on calorimeter information and hits in dedicated muon-trigger detectors, the LVL1 decision is made by the central-trigger processor yielding an output rate of less than 100 kHz. The allowed latency for the trigger decision at this stage is less than 2.5 microseconds. Installation of the final LVL1 trigger system at the ATLAS site is in full swing, to be completed later this year. We present a status report of the main components of the first-level trigger and the in-situ commissioning of the full trigger chain with cosmic-ray muons.

Thilo Pauly

2007-11-06T23:59:59.000Z

102

Cosmic Rays during BBN as Origin of Lithium Problem  

E-Print Network (OSTI)

There may be non-thermal cosmic rays during big-bang nucleosynthesis (BBN) epoch (dubbed as BBNCRs). This paper investigated whether such BBNCRs can be the origin of Lithium problem or not. It can be expected that BBNCRs flux will be small in order to keep the success of standard BBN (SBBN). With favorable assumptions on the BBNCR spectrum between 0.09 -- 4 MeV, our numerical calculation showed that extra contributions from BBNCRs can account for the $^7$Li abundance successfully. However $^6$Li abundance is only lifted an order of magnitude, which is still much lower than the observed value. As the deuteron abundance is very sensitive to the spectrum choice of BBNCRs, the allowed parameter space for the spectrum is strictly constrained. We should emphasize that the acceleration mechanism for BBNCRs in the early universe is still an open question. For example, strong turbulent magnetic field is probably the solution to the problem. Whether such a mechanism can provide the required spectrum deserves further studies.

Ming-ming Kang; Yang Hu; Hong-bo Hu; Shou-hua Zhu

2011-10-02T23:59:59.000Z

103

Transitional solar dynamics, cosmic rays and global warming  

E-Print Network (OSTI)

Solar activity is studied using a cluster analysis of the time-fluctuations of the sunspot number. It is shown that in an Historic period the high activity components of the solar cycles exhibit strong clustering, whereas in a Modern period (last seven solar cycles: 1933-2007) they exhibit a white-noise (non-)clustering behavior. Using this observation it is shown that in the Historic period, emergence of the sunspots in the solar photosphere was strongly dominated by turbulent photospheric convection. In the Modern period, this domination was broken by a new more active dynamics of the inner layers of the convection zone. Then, it is shown that the dramatic change of the sun dynamics at the transitional period (between the Historic and Modern periods, solar cycle 1933-1944yy) had a clear detectable impact on Earth climate. A scenario of a chain of transitions in the solar convective zone is suggested in order to explain the observations, and a forecast for the global warming is suggested on the basis of this scenario. A relation between the recent transitions and solar long-period chaotic dynamics has been found. Contribution of the galactic turbulence (due to galactic cosmic rays) has been discussed. These results are also considered in a content of chaotic climate dynamics at millennial timescales.

A. Bershadskii

2008-05-14T23:59:59.000Z

104

High-energy cosmic ray muons in the Earth's atmosphere  

Science Conference Proceedings (OSTI)

We present the calculations of the atmospheric muon fluxes at energies 10-10{sup 7} GeV based on a numerical-analytical method for solving the hadron-nucleus cascade equations. It allows the non-power-law behavior of the primary cosmic ray (PCR) spectrum, the violation of Feynman scaling, and the growth of the total inelastic cross sections for hadron-nucleus collisions with increasing energy to be taken into account. The calculations have been performed for a wide class of hadron-nucleus interaction models using directly the PCR measurements made in the ATIC-2 and GAMMA experiments and the parameterizations of the primary spectrum based on a set of experiments. We study the dependence of atmospheric muon flux characteristics on the hadronic interaction model and the influence of uncertainties in the PCR spectrum and composition on the muon flux at sea level. Comparison of the calculated muon energy spectra at sea level with the data from a large number of experiments shows that the cross sections for hadron-nucleus interactions introduce the greatest uncertainty in the energy region that does not include the knee in the primary spectrum.

Kochanov, A. A., E-mail: kochanov@iszf.irk.ru [Russian Academy of Sciences, Siberian Branch, Institute of Solar-Terrestrial Physics (Russian Federation); Sinegovskaya, T. S. [Irkutsk State Railway University (Russian Federation)] [Irkutsk State Railway University (Russian Federation); Sinegovsky, S. I., E-mail: sinegovsky@api.isu.ru [Irkutsk State University (Russian Federation)

2013-03-15T23:59:59.000Z

105

Simulations of cosmic ray feedback by AGN in galaxy clusters  

E-Print Network (OSTI)

We investigate a numerical model for AGN feedback where for the first time a relativistic particle population in AGN-inflated bubbles is followed within a full cosmological context. In our high-resolution simulations of galaxy cluster formation, we assume that BH accretion is accompanied by energy feedback that occurs in two different modes, depending on the accretion rate itself. Unlike in previous work, we inject a non-thermal particle population of relativistic protons into the AGN bubbles, instead of adopting a purely thermal heating. We then follow the subsequent evolution of the cosmic ray (CR) plasma inside the bubbles, considering both its hydrodynamical interactions and dissipation processes relevant for the CR population. Due to the different buoyancy of relativistic plasma and the comparatively long CR dissipation timescale we find substantial changes in the evolution of clusters as a result of CR feedback. In particular, the non-thermal population can provide significant pressure support in central cluster regions at low thermal temperatures, providing a natural explanation for the decreasing temperature profiles found in cool core clusters. At the same time, the morphologies of the bubbles and of the induced X-ray cavities show a striking similarity to observational findings. AGN feedback with CRs also proves efficient in regulating cluster cooling flows so that the total baryon fraction in stars becomes limited to realistic values of the order of 10%. We find that the partial CR support of the intracluster gas also affects the expected signal of the thermal Sunyaev-Zel'dovich effect, with typical modifications of the integrated Compton-y parameter within the virial radius of the order of 10%. [Abridged

D. Sijacki; C. Pfrommer; V. Springel; T. A. Ensslin

2008-01-21T23:59:59.000Z

106

The Interplanetary Network Supplement to the BATSE 5B Catalog of Cosmic Gamma-Ray Bursts  

E-Print Network (OSTI)

The Interplanetary Network Supplement to the BATSE 5B Catalog of Cosmic Gamma-Ray Bursts K. Hurley Interplanetary Network (IPN) localization information for 343 gamma-ray bursts observed by the Burst Gamma-Ray Observatory (CGRO) mission, obtained by analyzing the arrival times of these bursts

California at Berkeley, University of

107

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE BATSE CATALOGS OF UNTRIGGERED COSMIC GAMMA-RAY BURSTS  

E-Print Network (OSTI)

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE BATSE CATALOGS OF UNTRIGGERED COSMIC GAMMA-RAY BURSTS gamma-ray bursts (GRBs) observed as untriggered events by the Burst and Transient Source Experiment to detect BATSE un- triggered bursts. Subject headinggs: catalogs -- gamma rays: bursts Online material

California at Berkeley, University of

108

UHECR ESCAPE MECHANISMS FOR PROTONS AND NEUTRONS FROM GAMMA-RAY BURSTS, AND THE COSMIC-RAY-NEUTRINO CONNECTION  

SciTech Connect

The paradigm that gamma-ray burst fireballs are the sources of the ultra-high energy cosmic rays (UHECRs) is being probed by neutrino observations. Very stringent bounds can be obtained from the cosmic-ray (proton)-neutrino connection, assuming that the UHECRs escape as neutrons. In this study, we identify three different regimes as a function of the fireball parameters: the standard ''one neutrino per cosmic ray'' case, the optically thick (to neutron escape) case, and the case where leakage of protons from the boundaries of the shells (direct escape) dominates. In the optically thick regime, the photomeson production is very efficient, and more neutrinos will be emitted per cosmic ray than in the standard case, whereas in the direct escape-dominated regime, more cosmic rays than neutrinos will be emitted. We demonstrate that, for efficient proton acceleration, which is required to describe the observed UHECR spectrum, the standard case only applies to a very narrow region of the fireball parameter space. We illustrate with several observed examples that conclusions on the cosmic-ray-neutrino connection will depend on the actual burst parameters. We also show that the definition of the pion production efficiency currently used by the IceCube collaboration underestimates the neutrino production in the optically thick case. Finally, we point out that the direct escape component leads to a spectral break in the cosmic-ray spectrum emitted from a single source. The resulting ''two-component model'' can be used to even more strongly pronounce the spectral features of the observed UHECR spectrum than the dip model.

Baerwald, Philipp; Bustamante, Mauricio; Winter, Walter, E-mail: philipp.baerwald@physik.uni-wuerzburg.de, E-mail: mauricio.bustamante@physik.uni-wuerzburg.de, E-mail: winter@physik.uni-wuerzburg.de [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, D-97074 Wuerzburg (Germany)

2013-05-10T23:59:59.000Z

109

AN AB INITIO MODEL FOR COSMIC-RAY MODULATION  

SciTech Connect

A proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays (CRs) is of vital importance for a better understanding of CR modulation in the heliosphere. This study presents an ab initio model for CR modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. This model is solved for solar minimum heliospheric conditions, utilizing boundary values chosen so that model results are in reasonable agreement with spacecraft observations of turbulence quantities in the solar ecliptic plane and along the out-of-ecliptic trajectory of the Ulysses spacecraft. These results are employed as inputs for modeled slab and two-dimensional (2D) turbulence energy spectra. The modeled 2D spectrum is chosen based on physical considerations, with a drop-off at the very lowest wavenumbers. There currently exist no models or observations for the wavenumber where this drop-off occurs, and it is considered to be the only free parameter in this study. The modeled spectra are used as inputs for parallel mean free path expressions based on those derived from quasi-linear theory and perpendicular mean free paths from extended nonlinear guiding center theory. Furthermore, the effects of turbulence on CR drifts are modeled in a self-consistent way, also employing a recently developed model for wavy current sheet drift. The resulting diffusion and drift coefficients are applied to the study of galactic CR protons and antiprotons using a 3D, steady-state CR modulation code, and sample solutions in fair to good agreement with multiple spacecraft observations are presented.

Engelbrecht, N. E.; Burger, R. A. [Center for Space Research, North-West University, Potchefstroom 2520 (South Africa)

2013-07-20T23:59:59.000Z

110

A cosmic-ray precursor model for a Balmer-dominated shock in Tycho's supernova remnant  

E-Print Network (OSTI)

We present a time-dependent cosmic-ray modified shock model for which the calculated H-alpha emissivity profile agrees well with the H-alpha flux increase ahead of the Balmer-dominated shock at knot g in Tycho's supernova remnant, observed by Lee et al (2007). The backreaction of the cosmic ray component on the thermal component is treated in the two-fluid approximation, and we include thermal particle injection and energy transfer due to the acoustic instability in the precursor. The transient state of our model that describes the current state of the shock at knot g, occurs during the evolution from a thermal gas dominated shock to a smooth cosmic-ray dominated shock. Assuming a distance of 2.3 kpc to Tycho's remnant we obtain values for the cosmic ray diffusion coefficient, the injection parameter, and the time scale for the energy transfer of 10^{24} cm^{2} s^{-1}, 4.2x10^{-3}, and 426 y, respectively. We have also studied the parameter space for fast (300 km s^{-1} - 3000 km s^{-1}), time-asymptotically steady shocks and have identified a branch of solutions, for which the temperature in the cosmic ray precursor typically reaches 2-6x10^{4} K and the bulk acceleration of the flow through the precursor is less than 10 km s^{-1}. These solutions fall into the low cosmic ray acceleration efficiency regime and are relatively insensitive to shock parameters. This low cosmic ray acceleration efficiency branch of solutions may provide a natural explanation for the line broadening of the H-alpha narrow component observed in non-radiative shocks in many supernova remnants.

A. Y. Wagner; J. -J. Lee; J. C. Raymond; T. W. Hartquist; S. A. E. G. Falle

2008-09-15T23:59:59.000Z

111

Lookup tables to compute high energy cosmic ray induced atmospheric ionization and changes in atmospheric chemistry  

E-Print Network (OSTI)

A variety of events such as gamma-ray bursts and supernovae may expose the Earth to an increased flux of high-energy cosmic rays, with potentially important effects on the biosphere. Existing atmospheric chemistry software does not have the capability of incorporating the effects of substantial cosmic ray flux above 10 GeV . An atmospheric code, the NASA-Goddard Space Flight Center two-dimensional (latitude, altitude) time-dependent atmospheric model (NGSFC), is used to study atmospheric chemistry changes. Using CORSIKA, we have created tables that can be used to compute high energy cosmic ray (10 GeV - 1 PeV) induced atmospheric ionization and also, with the use of the NGSFC code, can be used to simulate the resulting atmospheric chemistry changes. We discuss the tables, their uses, weaknesses, and strengths.

Dimitra Atri; Adrian L. Melott; Brian C. Thomas

2008-04-20T23:59:59.000Z

112

Spectrum and Charge Ratio of Vertical Cosmic Ray Muons up to Momenta of 2.5 TeV/c  

SciTech Connect

The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5 TeV/c has been obtained by correcting for the overburden of 320 meter water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies up to 10{sup 15} eV.

Schmelling, M.; /Heidelberg, Max Planck Inst.; Hashim, N.O.; /Kenyatta U. Coll.; Grupen, C.; /Siegen U.; Luitz, S.; /SLAC; Maciuc, F.; /Heidelberg, Max Planck Inst.; Mailov, A.; /Siegen U.; Muller, A.-S.; /Karlsruhe, Inst. Technol.; Sander, H.-G.; /Mainz U., Inst. Phys.; Schmeling, S.; /CERN; Tcaciuc, R.; /Siegen U.; Wachsmuth, H.; /CERN; Zuber, K.; /Dresden, Tech. U.

2012-09-14T23:59:59.000Z

113

TeV Burst of Gamma-Ray Bursts and Ultra High Energy Cosmic Rays  

E-Print Network (OSTI)

Some recent experiments detecting very high energy (VHE) gamma-rays above 10-20 TeV independently reported VHE bursts for some of bright gamma-ray bursts (GRBs). If these signals are truly from GRBs, these GRBs must emit a much larger amount of energy as VHE gamma-rays than in the ordinary photon energy range of GRBs (keV-MeV). We show that such extreme phenomena can be reasonably explained by synchrotron radiation of protons accelerated to \\sim 10^{20-21} eV, which has been predicted by Totani (1998a). Protons seem to carry about (m_p/m_e) times larger energy than electrons, and hence the total energy liberated by one GRB becomes as large as \\sim 10^{56} (\\Delta \\Omega / 4 \\pi) ergs. Therefore a strong beaming of GRB emission is highly likely. Extension of the VHE spectrum beyond 20 TeV gives a nearly model-independent lower limit of the Lorentz factor of GRBs, as $\\gamma \\gtilde 500$. Furthermore, our model gives the correct energy range and time variability of ordinary keV-MeV gamma-rays of GRBs by synchrotron radiation of electrons. Therefore the VHE bursts of GRBs strongly support the hypothesis that ultra high energy cosmic rays observed on the Earth are produced by GRBs.

Tomonori Totani

1998-10-14T23:59:59.000Z

114

Air Cherenkov Methods in Cosmic Rays: A Review and Some History  

E-Print Network (OSTI)

The history of application of the Cherenkov light emission in the atmosphere to cosmic ray and gamma-ray astronomy studies is briefly outlined with an emphasis on the pioneering activity of A.E. Chudakov. The present-day situation and some new ideas are also discussed.

A. S. Lidvansky

2005-04-12T23:59:59.000Z

115

Changes in cosmic ray cut-o rigidities due to secular variations of the geomagnetic eld  

E-Print Network (OSTI)

Changes in cosmic ray cut-o rigidities due to secular variations of the geomagnetic ®eld A. Bhattacharyya1 , B. Mitra2 1 Indian Institute of Geomagnetism, Colaba, Bombay 400005, India 2 Department rays arriving at a point in an arbitrary direction, when the main geomagnetic ®eld is approximated

Paris-Sud XI, Université de

116

Cosmic-ray propagation properties for an origin in supernova remnants  

SciTech Connect

We have studied the impact of cosmic-ray acceleration in SNR on the spectra of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation equation, which allows us to use analytical solutions for part of the problem and an efficient numerical treatment of the remaining equations and thus accurately describes the cosmic-ray propagation on small scales around their sources in three spatial dimensions and time. We found strong variations of the cosmic-ray nuclei flux by typically 20% with occasional spikes of much higher amplitude, but only minor changes in the spectral distribution. The locally measured spectra of primary cosmic rays fit well into the obtained range of possible spectra. We further showed that the spectra of the secondary element Boron show almost no variations, so that the above findings also imply significant fluctuations of the Boron-to-Carbon ratio. Therefore the commonly used method of determining CR propagation parameters by fitting secondary-to-primary ratios appears flawed on account of the variations that these ratios would show throughout the Galaxy.

Pohl, M. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011-3160 (United States); Buesching, I. [Ruhr-Universitaet Bochum, 44780 Bochum (Germany); Kopp, A. [MPI fuer Sonnensystemforschung, 37191 Katleburg Lindau (Germany); Schlickeiser, R. [Ruhr University Bochum, 44780 Bochum (Germany); Perrot, C. [W.W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Grenier, I. [Universite Paris VII and CEA/Saclay, Service d'Astrophysique, 91191 Gif-sur-Yvette (France)

2005-11-22T23:59:59.000Z

117

The Electron Injection Spectrum Determined by Anomalous Excesses in Cosmic Ray, Gamma Ray, and Microwave Signals  

E-Print Network (OSTI)

Recent cosmic ray, gamma ray, and microwave signals observed by Fermi, PAMELA, and WMAP indicate an unexpected primary source of e+e- at 10-1000 GeV. We fit these data to "standard backgrounds" plus a new source, assumed to be a separable function of position and energy. For the spatial part, we consider three cases: annihilating dark matter, decaying dark matter, and pulsars. In each case, we use GALPROP to inject energy in log-spaced energy bins and compute the expected cosmic-ray and photon signals for each bin. We then fit a linear combination of energy bins, plus backgrounds, to the data. We use a non-parametric fit, with no prior constraints on the spectrum except smoothness and non-negativity. In addition, we consider arbitrary modifications to the energy spectrum of the "ordinary" primary source function, fixing its spatial part, finding this alone to be inadequate to explain the PAMELA or WMAP signals. We explore variations in the fits due to choice of magnetic field, primary electron injection index, spatial profiles, propagation parameters, and fit regularization method. Dark matter annihilation fits well, where our fit finds a mass of ~1 TeV and a boost factor times energy fraction of ~70. While it is possible for dark matter decay and pulsars to fit the data, unconventionally high magnetic fields and radiation densities are required near the Galactic Center to counter the relative shallowness of the assumed spatial profiles. We also fit to linear combinations of these three scenarios, though the fit is much less constrained.

Tongyan Lin; Douglas P. Finkbeiner; Gregory Dobler

2010-04-07T23:59:59.000Z

118

Observation of Ultrahigh-Energy Cosmic Rays with the ANITA Balloon-Borne Radio Interferometer  

Science Conference Proceedings (OSTI)

We report the observation of 16 cosmic ray events with a mean energy of 1.5x10{sup 19} eV via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present measurements in the 300-900 MHz range, which are the first self-triggered, first ultrawide band, first far-field, and the highest energy sample of cosmic ray events collected with the radio technique. Their properties are inconsistent with current ground-based geosynchrotron models. The emission is 100% polarized in the plane perpendicular to the projected geomagnetic field. Fourteen events are seen to have a phase inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon. Based on a likelihood analysis, we estimate angular pointing precision of order 2 deg. for the event arrival directions.

Hoover, S.; Belov, K.; Vieregg, A. G.; Saltzberg, D. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Nam, J. [Department of Physics, Ewha Womans University, Seoul (Korea, Republic of); Gorham, P. W.; Allison, P.; Kowalski, J.; Learned, J. G.; Matsuno, S.; Miki, C.; Miocinovic, P.; Romero-Wolf, A.; Rosen, M.; Ruckman, L.; Varner, G. S. [Department of Physics and Astronomy, University of Hawaii, Manoa, Hawaii 96822 (United States); Grashorn, E.; Beatty, J. J.; Mercurio, B. C.; Palladino, K. [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)

2010-10-08T23:59:59.000Z

119

"Pre-Acceleration of Anomalous Cosmic Ray Ions at Recurrent Solar Wind Shocks" Interstellar pickup ions and solar wind ions are two main sources of anomalous cosmic ray (ACR) ions. An important  

E-Print Network (OSTI)

"Pre-Acceleration of Anomalous Cosmic Ray Ions at Recurrent Solar Wind Shocks" Interstellar pickup ions and solar wind ions are two main sources of anomalous cosmic ray (ACR) ions. An important unresolved theoretical issue is how such low-energy seed ions are pre-accelerated to energies sufficiently

Christian, Eric

120

Successive Measurements of Cosmic-Ray Antiproton Spectrum in a Positive Phase of the Solar Cycle  

E-Print Network (OSTI)

The energy spectrum of cosmic-ray antiprotons (¯p’s) has been measured by BESS successively in 1993, 1995, 1997 and 1998. In total, 848 ¯p’s were clearly identified in energy range 0.18 to 4.20 GeV. From these successive measurements of the ¯p spectrum at various solar activity, we discuss about the effect of the solar modulation and the origin of cosmic-ray ¯p’s. Measured ¯p/p ratios were nearly identical during this perfiod, and were consistent with a prediction taking the charge dependent solar modulation into account.

T. Maeno A; S. Orito B; H. Matsunaga B; K. Abe B; A. Yamamoto C; T. Yoshida C; K. Yoshimura B

2000-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Successive Measurements of Cosmic-Ray Antiproton Spectrum in a Positive Phase of the Solar Cycle  

E-Print Network (OSTI)

The energy spectrum of cosmic-ray antiprotons has been measured by BESS successively in 1993, 1995, 1997 and 1998. In total, 848 antiprotons were clearly identified in energy range 0.18 to 4.20 GeV. From these successive measurements of the antiproton spectrum at various solar activity, we discuss about the effect of the solar modulation and the origin of cosmic-ray antiprotons. Measured antiproton ratios were nearly identical during this period, and were consistent with a prediction taking the charge dependent solar modulation into account.

T. Maeno; S. Orito; H. Matsunaga; BESS Collaboration

2000-10-19T23:59:59.000Z

122

The Performance of CRTNT Fluorescence Light Detector for Sub-EeV Cosmic Ray Observation  

E-Print Network (OSTI)

Cosmic Ray Tau Neutrino Telescopes (CRTNT) using for sub-EeV cosmic ray measurement is discussed. Performances of a stereoscope configuration with a tower of those telescopes plus two side-triggers are studied. This is done by using a detailed detector simulation driven by Corsika. Detector aperture as a function of shower energy above 10^17 eV is calculated. Event rate of about 20k per year for the second knee measurement is estimated. Event rate for cross calibration with detectors working on higher energy range is also estimated. Different configurations of the detectors are tried for optimization.

Y. Bai; G. Xiao; Z. Cao

2006-02-22T23:59:59.000Z

123

Prompt TeV Emission from Cosmic Rays Accelerated by Gamma Ray Bursts Interacting with Surrounding Stellar Wind  

E-Print Network (OSTI)

Protons accelerated in the internal shocks of a long duration gamma ray burst can escape the fireball as cosmic rays by converting to neutrons. Hadronic interactions of these neutrons inside a stellar wind bubble created by the progenitor star will produce TeV gamma rays via neutral meson decay and synchrotron radiation by charged pion-decay electrons in the wind magnetic field. Such gamma rays should be observable from nearby gamma ray bursts by currently running and upcoming ground-based detectors.

Soebur Razzaque; Olga Mena; Charles D. Dermer

2008-10-07T23:59:59.000Z

124

Galactic gamma-ray bursters - an alternative source of cosmic rays at all energies  

E-Print Network (OSTI)

We propose a new hypothesis for the origin of the major part of non-solar hadronic cosmic rays (CRs) at all energies: highly relativistic, narrowly collimated jets from the birth or collapse of neutron stars (NSs) in our Galaxy accelerate ambient disk and halo matter to CR energies and disperse it in hot spots which they form when they stop in the Galactic halo. Such events are seen as cosmological gamma-ray bursts (GRBs) in other galaxies when their beamed radiation happens to point towards Earth. This source of CRs is located in the Galactic halo. It therefore explains the absence of the Greisen-Zatsepin-Kuz'min cutoff in the spectrum of the ultra-high energy CRs. The position in energy of the ``ankle'' in the CR energy spectrum is shown to arise in a natural way. Moreover, an origin of lower energy CRs in the Galactic halo naturally accounts for the high degree of isotropy of CRs around 100 TeV from airshower observations, and the small galactocentric gradient of low-energy CRs derived from gamma-ray observations.

A. Dar; R. Plaga

1999-02-09T23:59:59.000Z

125

Modeling high-energy cosmic ray induced terrestrial and atmospheric neutron flux: A lookup table  

E-Print Network (OSTI)

Under current conditions, the cosmic ray spectrum incident on the Earth is dominated by particles with energies solar flares, supernovae and gamma ray bursts produce high energy cosmic rays (HECRs) with drastically higher energies. The Earth is likely episodically exposed to a greatly increased HECR flux from such events, some of which lasting thousands to millions of years. The air showers produced by HECRs ionize the atmosphere and produce harmful secondary particles such as muons and neutrons. Neutrons currently contribute a significant radiation dose at commercial passenger airplane altitude. With higher cosmic ray energies, these effects will be propagated to ground level. This work shows the results of Monte Carlo simulations quantifying the neutron flux due to high energy cosmic rays at various primary energies and altitudes. We provide here lookup tables that can be used to determine neutron fluxes from primaries with total energies 1 GeV - 1 PeV. By convolution, one can compute the neutron flux for any arbitrary CR spectrum. Our results demonstrate that deducing the nature of primaries from ground level neutron enhancements would be very difficult.

Andrew Overholt; Adrian Melott; Dimitra Atri

2012-06-22T23:59:59.000Z

126

Cosmic Ray Models for Early Galactic Lithium, Beryllium, and Boron Production  

E-Print Network (OSTI)

To understand better the early galactic production of Li, Be, and B by cosmic ray spallation and fusion reactions, the dependence of these production rates on cosmic ray models and model parameters is examined. The sensitivity of elemental and isotopic production to the cosmic ray pathlength magnitude and energy dependence, source spectrum, spallation kinematics, and cross section uncertainties is studied. Changes in these model features, particularly those features related to confinement, are shown to alter the Be- and B-versus-Fe slopes {}from a na\\"{\\i}ve quadratic relation. The implications of our results for the diffuse $\\gamma$-ray background are examined, and the role of chemical evolution and its relation to our results is noted. It is also noted that the unmeasured high energy behavior of $\\alpha+\\alpha$ fusion can lead to effects as large as a factor of 2 in the resultant yields. Future data should enable Population II Li, Be, and B abundances to constrain cosmic ray models for the early Galaxy.

Brian Fields; Keith Olive; David Schramm

1994-05-11T23:59:59.000Z

127

Modeling high-energy cosmic ray induced terrestrial muon flux: A lookup table  

E-Print Network (OSTI)

On geological timescales, the Earth is likely to be exposed to an increased flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. Typical cosmic ray energies may be much higher than the ~ 1 GeV flux which normally dominates. These high-energy particles strike the Earth's atmosphere initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the radiation dose. Muons contribute 85% to the radiation dose from cosmic rays. This enhanced dose could be potentially harmful to the biosphere. This mechanism has been discussed extensively in literature but has never been quantified. Here, we have developed a lookup table that can be used to quantify this effect by modeling terrestrial muon flux from any arbitrary cosmic ray spectra with 10 GeV - 1 PeV primaries. This will enable us to compute the radiation dose on terrestrial planetary surfaces from a number of astrophysical sources.

Dimitra Atri; Adrian L. Melott

2010-11-19T23:59:59.000Z

128

Correlation of the highest energy cosmic rays with nearby extragalactic objects  

E-Print Network (OSTI)

Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above ~ 6x10^{19} electron volts and the positions of active galactic nuclei (AGN) lying within ~ 75 megaparsecs. We rejected the hypothesis of an isotropic distribution of these cosmic rays with at least a 99% confidence level from a prescribed a priori test. The correlation we observed is compatible with the hypothesis that the highest energy particles originate from nearby extragalactic sources whose flux has not been substantially reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.

The Pierre Auger Collaboration

2007-11-14T23:59:59.000Z

129

Extremely High Energy Neutrinos, Neutrino Hot Dark Matter, and the Highest Energy Cosmic Rays  

E-Print Network (OSTI)

Extremely high energy (up to 10**(22) eV) cosmic neutrino beams initiate high energy particle cascades in the background of relic neutrinos from the Big Bang. We perform numerical calculations to show that such cascades could contribute more than 10% to the observed cosmic ray flux above 10**(19) eV if neutrinos have masses in the electron volt range. The required intensity of primary neutrinos could be consistent with astrophysical models for their production if the maximum neutrino energy reaches to 10**(22) eV and the massive neutrino dark matter is locally clustered. Future observations of ultra high energy cosmic rays will lead to an indirect but practical search for neutrino dark matter.

Shigeru Yoshida; Guenter Sigl; Sangjin Lee

1998-08-14T23:59:59.000Z

130

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 The HEAT Telescopes of the Pierre Auger Observatory  

E-Print Network (OSTI)

tanks on a 750 m grid close to the HEAT site the energy range of high quality hybrid air shower32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 The HEAT Telescopes of the Pierre Auger. A surface array of 1660 water Cherenkov detectors on a 1500 m triangular grid covers an area of 3000 km2

Hörandel, Jörg R.

131

Test with cosmic rays of the GEM chambers for the LHCb muon system produced in Cagliari  

E-Print Network (OSTI)

The inner region of the first LHCb muon station will be equipped with twelve Gas Electron Multiplier chambers. The seven chambers produced in Cagliari were studied for several days each using cosmic rays. We measured the efficiency, timing resolution, and uniformity, cluster-size and out-of-time multiplicity. We find all seven chambers perform well.

Bonivento, W; Oldeman, R G C

2007-01-01T23:59:59.000Z

132

Intensity of Upward Muon Flux Due to Cosmic-Ray Neutrinos Produced in the Atmosphere  

DOE R&D Accomplishments (OSTI)

Calculations were performed to determine the upward going muon flux leaving the earth's surface after production by cosmic-ray neutrinos in the crust. Only neutrinos produced in the earth's atmosphere are considered. Rates of the order of one per 100 sq m/day might be expected if an intermediate boson exists and has a mass less than 2 Bev. (auth)

Lee, T. D.; Robinson, H.; Schwartz, M.; Cool, R.

1963-06-00T23:59:59.000Z

133

Environmental limits on the non-resonant cosmic-ray current-driven instability  

E-Print Network (OSTI)

We investigate the so-called non-resonant cosmic-ray streaming instability, first discussed by Bell (2004). The extent to which thermal damping and ion-neutral collisions reduce the growth of this instability is calculated. Limits on the growth of the non-resonant mode in SN1006 and RX J1713.7-3946 are presented.

B. Reville; J. G. Kirk; P. Duffy; S. O'Sullivan

2008-02-22T23:59:59.000Z

134

Cosmic Ray Hits in the Central Nervous System at Solar Maximum  

Science Conference Proceedings (OSTI)

It has been suggested that a manned mission to Mars be launched at solar maximum rather than at solar minimum to minimize the radiation exposure to galactic cosmic rays. It is true that the number of hits from highly ionizing particles to critical regions ...

Curtis S. B.; Vazquez M. E.; Wilson J. W.; Kim M.-H. Y.

1998-07-01T23:59:59.000Z

135

On the periodic variations of secondary cosmic rays and the geomagnetic Pc4 pulsations in BMAr  

E-Print Network (OSTI)

On the periodic variations of secondary cosmic rays and the geomagnetic Pc4 pulsations in BMAr I. M are accompanied by the geomagnetic Pc4 pulsations and have similar periodicity. The phenomenon was observed over of geomagnetic ®eld were observed simultaneously with apparent peri- odicity in the count rates of charged

Paris-Sud XI, Université de

136

Search for a dark matter particle in high energy cosmic rays  

E-Print Network (OSTI)

Existing data hints that high energy cosmic ray experiments may offer the most promissing shot at finding a dark matter particle. A search in the PeV mass range is suggested, where the discovery of such a particle might help explain the GZK cutoff violation data.

Yukio Tomozawa

2008-04-09T23:59:59.000Z

137

On the origin and acceleration of cosmic rays: Cooling flow clusters and AGN hosts  

E-Print Network (OSTI)

We are looking for radio `relics' and `halos' in an X-ray selected sample of clusters of galaxies. These radio features are not a product of the Active Galactic Nuclei (AGN)-mechanism, but more likely are associated with past cluster merger events. AGN hosts of cooling flow clusters contain particle bubbles that show non-thermal radio emission. These bubbles could explain the presence of radio relics and halos if they can restrict cosmic rays efficiently. Intracluster magnetic fields and cluster environments can reveal the acceleration mechanisms of cosmic rays. Using radio/X-ray data and analytical methods we examine three AGN hosts out of our 70 clusters, namely Hercules A, 3C310 and 3C388. We found that none of these clusters contain relics and/or halos.

Gizani, Nectaria A B

2011-01-01T23:59:59.000Z

138

Ultra-high energy cosmic rays, cascade gamma-rays, and high-energy neutrinos from gamma-ray bursts  

E-Print Network (OSTI)

Gamma-ray bursts (GRBs) are sources of energetic, highly variable fluxes of gamma rays, which demonstrates that they are powerful particle accelerators. Besides relativistic electrons, GRBs should also accelerate high-energy hadrons, some of which could escape cooling to produce ultra-high energy cosmic rays (UHECRs). Acceleration of high-energy hadrons in GRB blast waves will be established if high-energy neutrinos produced through photopion interactions in the blast wave are detected from GRBs. Limitations on the energy in nonthermal hadrons and the number of expected neutrinos are imposed by the fluxes from pair-photon cascades initiated in the same processes that produce neutrinos. Only the most powerful bursts at fluence levels >~ 3e-4 erg/cm^2 offer a realistic prospect for detection of >> TeV neutrinos. Detection of high-energy neutrinos is likely if GRB blast waves have large baryon loads and Doppler factors <~ 200. Cascade gamma rays will accompany neutrino production and might already have been detected as anomalous emission components in the spectra of some GRBs. Prospects for detection of GRBs in the Milky Way are also considered.

Charles D. Dermer; Armen Atoyan

2006-06-26T23:59:59.000Z

139

X-ray Stripes in Tycho's Supernova Remant: Synchrotron Footprints of a Nonlinear Cosmic Ray-driven Instability  

E-Print Network (OSTI)

High-resolution Chandra observations of Tycho's SNR have revealed several sets of quasi-steady, high-emissivity, nearly-parallel X-ray stripes in some localized regions of the SNR. These stripes are most likely the result of cosmic-ray (CR) generated magnetic turbulence at the SNR blast wave. However, for the amazingly regular pattern of these stripes to appear requires the simultaneous action of a number of shock-plasma phenomena and is not predicted by most models of magnetic field amplification. A consistent explanation of these stripes yields information on the complex nonlinear plasma processes connecting efficient CR acceleration and magnetic field fluctuations in strong collisionless shocks. The nonlinear diffusive shock acceleration (NL-DSA) model described here, which includes magnetic field amplification from a cosmic-ray current driven instability, does predict stripes consistent with the synchrotron emission observations of Tycho's SNR. We argue that the local ambient mean magnetic field geometry ...

Bykov, A M; Osipov, S M; Pavlov, G G; Uvarov, Yu A

2011-01-01T23:59:59.000Z

140

A Gamma-Ray Burst/Pulsar for Cosmic-Ray Positrons with a Dark Matter-like Spectrum  

E-Print Network (OSTI)

We propose that a nearby gamma-ray burst (GRB) or GRB-like (old, single and short-lived) pulsar/supernova remnant/microquasar about 10^{5-6} years ago may be responsible for the excesses of cosmic-ray positrons and electrons recently observed by the PAMELA, ATIC/PPB-BETS, Fermi and HESS experiments. We can reproduce the smooth Fermi/HESS spectra as well as the spiky ATIC/PPB-BETS spectra. The spectra have a sharp cutoff that is similar to the dark matter predictions, sometimes together with a line (not similar), since higher energy cosmic-rays cool faster where the cutoff/line energy marks the source age. A GRB-like astrophysical source is expected to have a small but finite spread in the cutoff/line as well as anisotropy in the cosmic-ray and diffuse gamma-ray flux, providing a method for the Fermi and future CALET experiments to discriminate between dark matter and astrophysical origins.

Kunihito Ioka

2008-12-30T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Superconducting cosmic strings as gamma ray burst engines  

E-Print Network (OSTI)

Cusps of superconducting strings can serve as GRB engines. A powerful beamed pulse of electromagnetic radiation from a cusp produces a jet of accelerated particles, whose propagation is terminated by the shock responsible for GRB. A single free parameter, the string scale of symmetry breaking $\\eta \\sim 10^{14} GeV$, together with reasonable assumptions about the magnitude of cosmic magnetic fields and the fraction of volume that they occupy, explains the GRB rate, duration and fluence, as well as the observed ranges of these quantities. The wiggles on the string can drive the short-time structures of GRB. This model predicts that GRBs are accompanied by strong bursts of gravitational radiation which should be detectable by LIGO, VIRGO and LISA detectors.

V. Berezinsky; B. Hnatyk; A. Vilenkin

2000-01-12T23:59:59.000Z

142

High Redshift Gamma-Ray Bursts: Observational Signatures of Superconducting Cosmic Strings?  

E-Print Network (OSTI)

The high-redshift gamma-ray bursts (GRBs), GRBs 080913 and 090423, challenge the conventional GRB progenitor models by their short durations, typical for short GRBs, and their high energy releases, typical for long GRBs. Meanwhile, the GRB rate inferred from high-redshift GRBs also remarkably exceeds the prediction of the collapsar model, with an ordinary star formation history. We show that all these contradictions could be eliminated naturally, if we ascribe some high-redshift GRBs to electromagnetic bursts of superconducting cosmic strings. High-redshift GRBs could become a reasonable way to test the superconducting cosmic string model, because the event rate of cosmic string bursts increases rapidly with increasing redshifts, whereas the collapsar rate decreases.

K. S. Cheng; Yun-Wei Yu; T. Harko

2010-05-19T23:59:59.000Z

143

First Results From GLAST-LAT Integrated Towers Cosmic Ray Data Taking And Monte Carlo Comparison  

SciTech Connect

GLAST Large Area Telescope (LAT) is a gamma ray telescope instrumented with silicon-strip detector planes and sheets of converter, followed by a calorimeter (CAL) and surrounded by an anticoincidence system (ACD). This instrument is sensitive to gamma rays in the energy range between 20 MeV and 300 GeV. At present, the first towers have been integrated and pre-launch data taking with cosmic ray muons is being performed. The results from the data analysis carried out during LAT integration will be discussed and a comparison with the predictions from the Monte Carlo simulation will be shown.

Brigida, M.; Caliandro, A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giordano, F.; Giglietto, N.; Loparco, F.; Marangelli, B.; Mazziotta, M.N.; Mirizzi, N.; Raino, S.; Spinelli, P.; /Bari U. /INFN, Bari

2007-02-15T23:59:59.000Z

144

Cosmic ray knee and new physics at the TeV scale  

E-Print Network (OSTI)

We analyze the possibility that the cosmic ray knee appears at an energy threshold where the proton-dark matter cross section becomes large due to new TeV physics. It has been shown that such interactions could break the proton and produce a diffuse gamma ray flux consistent with MILAGRO observations. We argue that this hypothesis implies knees that scale with the atomic mass for the different nuclei, as KASKADE data seem to indicate. We find that to explain the change in the spectral index in the flux from E^{-2.7} to E^{-3.1} the cross section must grow like E^{0.4+\\beta} above the knee, where \\beta=0.3-0.6 parametrizes the energy dependence of the age (\\tau \\propto E^{-\\beta}) of the cosmic rays reaching the Earth. The hypothesis also requires mbarn cross sections (that could be modelled with TeV gravity) and large densities of dark matter (that could be clumped around the sources of cosmic rays). We argue that neutrinos would also exhibit a threshold at E=(m_\\chi/m_p)E_{knee}\\approx 10^8 GeV where their interaction with a nucleon becomes strong. Therefore, the observation at ICECUBE or ANITA of standard neutrino events above this threshold would disprove the scenario.

Roberto Barcelo; Manuel Masip; Iacopo Mastromatteo

2009-03-30T23:59:59.000Z

145

Study of the ultrahigh-energy primary-cosmic-ray composition with the MACRO experiment  

Science Conference Proceedings (OSTI)

We present the analysis of multiple-muon events collected with one supermodule (1013 h live time) and two supermodules (1195 h live time) of the MACRO detector at Gran Sasso, Italy. Multimuon rates are shown to be sensitive to primary-cosmic-ray energies between {similar to}50 TeV and several thousand TeV. Experimental data are compared with the expected rates from two composition models: a light (i.e., proton-rich) and a heavy (i.e., Fe-rich) composition. The predictions are based on a Monte Carlo simulation of the hadronic interactions of cosmic-ray nuclei, followed by a detailed tracking of the muons through the rock and the experimental apparatus. The results show good sensitivity of the MACRO detector to primary composition. The data exhibit a preference towards the light composition model.

Ahlen, S.; Ambrosio, M.; Antolini, R.; Auriemma, G.; Baldini, A.; Bam, B.B.; Barbarino, G.C.; Barish, B.C.; Battistoni, G.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bisi, V.; Bloise, C.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, P.; Campana, D.; Carboni, M.; Cecchini, S.; Cei, F.; Chiarella, V.; Chiera, C.; Cobis, A.; Cormack, R.; Corona, A.; Coutu, S.; DeCataldo, G.; DeMarzo, C.; De Vincenzi, M.; Di Credico, A.; Diehl, E.; Erriquez, O.; Favuzzi, C.; Ficenec, D.; Forti, C.; Foti, L.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Giubellino, P.; Grassi, M.; Green, P.; Grillo, A.; Guarino, F.; Gustavino, C.; Habig, A.; Heinz, R.; Hong, J.T.; Iarocci, E.; Katsavounidis, E.; Kearns, E.; Klein, S.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Lee, C.; Levin, D.; Lipari, P.; Liu, G.; Liu, R.; Longo, M.J.; Ludlam, G.; Mancarella, G.; Mandrioli, G.; Margiotta-Neri, A.; Marin, A.; Marini, A.; Martello, D.; Martellotti, G.; Marzari Chiesa, A.; Masera, M.; Matteuzzi; (MACRO Collaboration)

1992-08-01T23:59:59.000Z

146

PARSEC: A Parametrized Simulation Engine for Ultra-High Energy Cosmic Ray Protons  

E-Print Network (OSTI)

We present a new simulation engine for fast generation of ultra-high energy cosmic ray data based on parametrizations of common assumptions of UHECR origin and propagation. Implemented are deflections in unstructured turbulent extragalactic fields, energy losses for protons due to photo-pion production and electron-pair production, as well as effects from the expansion of the universe. Additionally, a simple model to estimate propagation effects from iron nuclei is included. Deflections in galactic magnetic fields are included using a matrix approach with precalculated lenses generated from backtracked cosmic rays. The PARSEC program is based on object oriented programming paradigms enabling users to extend the implemented models and is steerable with a graphical user interface.

Bretz, Hans-Peter

2013-01-01T23:59:59.000Z

147

Recommendations for a Static Cosmic Ray Shield for Enriched Germanium Detectors  

SciTech Connect

This document provides a detailed study of cost and materials that could be used to shield the detector material of the international Tonne-scale germanium neutrinoless double-beta decay experiment from hadronic particles from cosmic ray showers at the Earth's surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during storage; in particular, when the detector material is being worked on at the detector manufacturer's facility. This work considers two options for shielding the detector material from cosmic ray particles. One option is to use a pre-existing structure already located near the detector manufacturer, such as Canberra Industries in Meriden, Connecticut. The other option is to build a shield onsite at a detector manufacturer's site. This paper presents a cost and efficiency analysis of such construction.

Aguayo Navarrete, Estanislao; Orrell, John L.; Ankney, Austin S.; Berguson, Timothy J.

2011-09-21T23:59:59.000Z

148

Photon damping in cosmic-ray acceleration in active galactic nuclei  

SciTech Connect

The usual assumption of the acceleration of ultra high energy cosmic rays, greater than or equal to 10/sup 18/ eV in quasars, Seyfert galaxies and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10/sup 20/ eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10/sup 15/. Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultra high energy. Hence, it is unlikely that any reasonable configuration of acceleration can void disastrous photon energy loss. A different site for ultra high energy cosmic ray acceleration must be found.

Colgate, S.A.

1983-04-07T23:59:59.000Z

149

Observations of the Li, Be, and B isotopes and Constraints on Cosmic-ray Propagation  

Science Conference Proceedings (OSTI)

The abundance of Li, Be, and B isotopes in galactic cosmic rays (GCR) between E=50-200 MeV/nucleon has been observed by the Cosmic Ray Isotope Spectrometer (CRIS) on NASA's ACE mission since 1997 with high statistical accuracy. Precise observations of Li, Be, B can be used to constrain GCR propagation models. We find that a diffusive reacceleration model with parameters that best match CRIS results (e.g. B/C, Li/C, etc) are also consistent with other GCR observations. A {approx}15-20% overproduction of Li and Be in the model predictions is attributed to uncertainties in the production cross-section data. The latter becomes a significant limitation to the study of rare GCR species that are generated predominantly via spallation.

de Nolfo, Georgia A.; Moskalenko, I.V.; Binns, W.R.; Christian, E.R.; Cummings, A.C.; Davis, A.J.; George, J.S.; Hink, P.L.; Israel, M.H.; Leske, R.A.; Lijowski, M.; Mewaldt, R.A.; Stone, E.C.; Strong, A.W.; von Rosenvinge, T.T.; Wiedenbeck, M.E.; Yanasak, N.E.; /NASA, Goddard /Stanford U., HEPL /Washington U., St. Louis /NASA, Headquarters /Caltech, SRL /Aerospace Corp. /Garching, Max Planck Inst., MPE /Caltech, JPL

2006-11-15T23:59:59.000Z

150

THE CENTAURUS A ULTRAHIGH-ENERGY COSMIC-RAY EXCESS AND THE LOCAL EXTRAGALACTIC MAGNETIC FIELD  

SciTech Connect

The ultrahigh-energy cosmic-ray (UHECR) anisotropies discovered by the Pierre Auger Observatory provide the potential to finally address both the particle origins and properties of the nearby extragalactic magnetic field (EGMF). We examine the implications of the excess of {approx}10{sup 20} eV events around the nearby radio galaxy Centaurus A. We find that, if Cen A is the source of these cosmic rays, the angular distribution of events constrains the EGMF strength within several Mpc of the Milky Way to {approx}> 20 nG for an assumed primary proton composition. Our conclusions suggest that either the observed excess is a statistical anomaly or the local EGMF is stronger than conventionally thought. We discuss several implications, including UHECR scattering from more distant sources, time delays from transient sources, and the possibility of using magnetic lensing signatures to attain tighter constraints.

Yueksel, Hasan; Kronberg, Philipp P. [Theoretical Division, MS B285, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stanev, Todor [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Kistler, Matthew D. [Lawrence Berkeley National Laboratory and Department of Physics, University of California, Berkeley, CA 94720 (United States)

2012-10-10T23:59:59.000Z

151

Probing Solar Magnetic Field with the "Cosmic-Ray Shadow" of the Sun  

E-Print Network (OSTI)

We report on a clear solar-cycle variation of the Sun's shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun's shadow, using the Potential Field Source Surface (PFSS) model and the Current Sheet Source Surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun's shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun's shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun's shadow observed in the TeV cosmic-ray flux.

Amenomori, M; Chen, D; Chen, T L; Chen, W Y; Cui, S W; Danzengluobu,; Ding, L K; Feng, C F; Feng, Zhaoyang; Feng, Z Y; Gou, Q B; Guo, Y Q; Hakamada, K; He, H H; He, Z T; Hibino, K; Hotta, N; Hu, Haibing; Hu, H B; Huang, J; Jia, H Y; Jiang, L; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Labaciren,; Le, G M; Li, A F; Li, H J; Li, W J; Liu, C; Liu, J S; Liu, M Y; Lu, H; Meng, X R; Mizutani, K; Munakata, K; Nanjo, H; Nishizawa, M; Ohnishi, M; Ohta, I; Onuma, H; Ozawa, S; Qian, X L; Qu, X B; Saito, T; Saito, T Y; Sakata, M; Sako, T K; Shao, J; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, H; Wu, H R; Xue, L; Yamamoto, Y; Yang, Z; Yasue, S; Yuan, A F; Yuda, T; Zhai, L M; Zhang, H M; Zhang, J L; Zhang, X Y; Zhang, Y; Zhang, Yi; Zhang, Ying; Zhaxisangzhu,; Zhou, X X

2013-01-01T23:59:59.000Z

152

Asymptotic directions for selecte cosmic-ray stations calculated using the International Geomagnetic Reference Field for 1980  

SciTech Connect

Asymptotic directions for high-energy solar particles are given for selected cosmic-ray stations. These values were calculated employing the International Geomagnetic Reference Field model for Epoch 1980.0.

Shea, M.A.; Smart, D.F.; Gentile, L.

1987-07-01T23:59:59.000Z

153

CRaTER: The Cosmic Ray Telescope for the Effects of Radiation Experiment on the Lunar Reconnaissance Orbiter Mission  

E-Print Network (OSTI)

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO) characterizes the radiation environment to be experienced by humans during future lunar missions. CRaTER measures the ...

Spence, H. E.

154

Simulation of the Cosmic Ray Moon Shadow in the Geomagnetic field  

E-Print Network (OSTI)

An accurate MonteCarlo simulation of the deficit of primary cosmic rays in the direction of the Moon has been developed to interpret the observations reported in the TeV energy region until now. Primary particles are propagated trough the geomagnetic field in the Earth-Moon system. The algorithm is described and the contributions of the detector resolution and of the geomagnetic field are disentangled.

Di Sciascio, G

2009-01-01T23:59:59.000Z

155

Strong variations of cosmic ray intensity during thunderstorms and associated pulsations of the geomagnetic field  

E-Print Network (OSTI)

Strong variations of the intensity of secondary cosmic rays during thunderstorms are found to be accompanied in some cases by very clear pulsations of the geomagnetic field. The experiment is carried out in the Baksan Valley, North Caucasus, the Carpet air shower array being used as a particle detector. Magnetic field measurements are made with high-precision magnetometers located deep underground in the tunnel of the Baksan Neutrino Observatory, several kilometers apart from the air shower array.

Kanonidi, K Kh; Lidvansky, A S; Sobisevich, L E

2011-01-01T23:59:59.000Z

156

Readout electronics of silicon detectors used in space cosmic-ray charges measurement  

E-Print Network (OSTI)

A readout electronics used in space cosmic-ray charges measurement for multi-channel silicon detector and its performance test results are introduced in this paper. A 64-channel charge sensitive ASIC (VA140) from IDEAS company is adopt in this method. With its features of low power consumption, low noise, large dynamic range and high integration, it can be used in future particle detecting experiments base on silicon detector.

Zhang Fei; Fan Rui-Rui; Peng Wen-Xi; Dong Yi-Fan; Gong Ke; Liang Xiao-Hua; Liu Ya-Qing; Wang Huan-Yu

2013-07-11T23:59:59.000Z

157

Detection and imaging of atmospheric radio flashes from cosmic ray air showers  

E-Print Network (OSTI)

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10^20 eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within ~50 Mpc through interactions with the cosmic microwave background. As there are no sufficient powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.

H. Falcke; W. D. Apel; A. F. Badea

2005-05-18T23:59:59.000Z

158

Silver isotopic anomalies in iron meteorites: cosmic-ray production and other possible sources  

Science Conference Proceedings (OSTI)

The sources of excess /sup 107/Ag observed in iron meteorites by Kaiser, Kelly, and Wasserburg (1980) are examined, with emphasis on the reactions of cosmic-ray particles with palladium. The cross sections for the production of the silver isotopes from palladium by energetic cosmic-ray particles are evaluated or estimated and used to calculate spallogenic production rates relative to that of /sup 53/Mn from iron. The upper limit for the production rate of excess /sup 107/Ag by galactic-cosmic-ray particles is 400 atoms/min/kg(Pd) which, over an exposure age of 10/sup 9/ years, would make only 1% of the observed excesses of /sup 107/Ag. Neutron-capture reactions with Pd isotopes produce mainly /sup 109/Ag. Binary fission of a siderophilic superheavy element would be expected to yield more /sup 109/Ag than /sup 107/Ag. An intense proton irradiation in the early solar system probably would produce a lower ratio of (/sup 107/Pd//sup 108/Pd) to (/sup 26/Al//sup 27/Al) than observed in meteorites. Therefore the presence of excess /sup 107/Ag in iron meteorites with large Pd/Ag ratios very likely is due to the incorporation of 6.5 x 10/sup 6/-year /sup 107/Pd of nucleosynthetic origin in these meteorites.

Reedy, R.C.

1980-04-18T23:59:59.000Z

159

Cosmic ray spectral hardening due to dispersion in the source injection spectra  

E-Print Network (OSTI)

Recent cosmic ray (CR) experiments discovered that the CR spectra experience a remarkable hardening for rigidity above several hundred GV. We propose that this is caused by the superposition of the CR energy spectra of many sources that have a dispersion in the injection spectral indices. Adopting similar parameters as those of supernova remnants derived from the Fermi $\\gamma$-ray observations, we can reproduce the observational CR spectra of different species well. This may be interpreted as evidence to support the supernova remnant origin of CRs below the knee. We further propose that the same mechanism may explain the "ankle" of the ultra high energy CR spectrum.

Qiang Yuan; Bing Zhang; Xiao-Jun Bi

2011-04-17T23:59:59.000Z

160

BLAZARS AS ULTRA-HIGH-ENERGY COSMIC-RAY SOURCES: IMPLICATIONS FOR TeV GAMMA-RAY OBSERVATIONS  

Science Conference Proceedings (OSTI)

The spectra of BL Lac objects and Fanaroff-Riley I radio galaxies are commonly explained by the one-zone leptonic synchrotron self-Compton (SSC) model. Spectral modeling of correlated multiwavelength data gives the comoving magnetic field strength, the bulk outflow Lorentz factor, and the emission region size. Assuming the validity of the SSC model, the Hillas condition shows that only in rare cases such sources accelerate protons to much above 10{sup 19} eV, so {approx}> 10{sup 20} eV ultra-high-energy cosmic rays (UHECRs) are likely to be heavy ions if powered by this type of radio-loud active galactic nuclei (AGNs). Survival of nuclei is shown to be possible in TeV BL Lacs and misaligned counterparts with weak photohadronic emissions. Another signature of hadronic production is intergalactic UHECR-induced cascade emission, which is an alternative explanation of the TeV spectra of some extreme non-variable blazars such as 1ES 0229+200 or 1ES 1101-232. We study this kind of cascade signal, taking into account effects of the structured extragalactic magnetic fields in which the sources should be embedded. We demonstrate the importance of cosmic-ray deflections on the {gamma}-ray flux, and show that required absolute cosmic-ray luminosities are larger than the average UHECR luminosity inferred from UHECR observations and can even be comparable to the Eddington luminosity of supermassive black holes. Future TeV {gamma}-ray observations using the Cerenkov Telescope Array and the High Altitude Water Cerenkov detector array can test for UHECR acceleration by observing >25 TeV photons from relatively low redshift sources such as 1ES 0229+200, and {approx}>TeV photons from more distant radio-loud AGNs.

Murase, Kohta [Department of Physics, Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Dermer, Charles D. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Takami, Hajime [Max Planck Institute for Physics, Foehringer Ring 6, 80805 Munich (Germany); Migliori, Giulia [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-04-10T23:59:59.000Z

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161

Atmospheric Calorimetry above 10$^{19}$ eV: Shooting Lasers at the Pierre Auger Cosmic-Ray Observatory  

E-Print Network (OSTI)

The Pierre Auger Cosmic-Ray Observatory uses the earth's atmosphere as a calorimeter to measure extensive air-showers created by particles of astrophysical origin. Some of these particles carry joules of energy. At these extreme energies, test beams are not available in the conventional sense. Yet understanding the energy response of the observatory is important. For example, the propagation distance of the highest energy cosmic-rays through the cosmic microwave background radiation (CMBR) is predicted to be strong function of energy. This paper will discuss recently reported results from the observatory and the use of calibrated pulsed UV laser "test-beams" that simulate the optical signatures of ultra-high energy cosmic rays. The status of the much larger 200,000 km$^3$ companion detector planned for the northern hemisphere will also be outlined.

L. Wiencke; for the Pierre Auger Collaboration

2008-07-17T23:59:59.000Z

162

Fermi Large Area Telescope Observations of the Cosmic-Ray Induced  

SciTech Connect

We report on measurements of the cosmic-ray induced {gamma}-ray emission of Earth's atmosphere by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. The LAT has observed the Earth during its commissioning phase and with a dedicated Earth-limb following observation in September 2008. These measurements yielded {approx} 6.4 x 10{sup 6} photons with energies > 100 MeV and {approx} 250 hours total livetime for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission - often referred to as Earth albedo gamma-ray emission - has a power-law shape up to 500 GeV with spectral index {Lambda} = 2.79 {+-} 0.06.

Abdo, A.

2012-02-29T23:59:59.000Z

163

Lorentz Invariance Violation and the Observed Spectrum of Ultrahigh Energy Cosmic Rays  

E-Print Network (OSTI)

There has been much interest in possible violations of Lorentz invariance, particularly motivated by quantum gravity theories. It has been suggested that a small amount of Lorentz invariance violation (LIV) could turn off photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with photons of the cosmic background radiation and thereby eliminate the resulting sharp steepening in the spectrum of the highest energy CRs predicted by Greisen Zatsepin and Kuzmin (GZK). Recent measurements of the UHECR spectrum reported by the HiRes and Auger collaborations, however, indicate the presence of the GZK effect. We present the results of a detailed calculation of the modification of the UHECR spectrum caused by LIV using the formalism of Coleman and Glashow. We then compare these results with the experimental UHECR data from Auger and HiRes. Based on these data, we find a best fit amount of LIV of $4.5^{+1.5}_{-4.5} \\times 10^{-23}$,consistent with an upper limit of $6 \\times 10^{-23}$. This possible amount of LIV can lead to a recovery of the cosmic ray spectrum at higher energies than presently observed. Such an LIV recovery effect can be tested observationally using future detectors.

S. T. Scully; F. W. Stecker

2008-11-13T23:59:59.000Z

164

Aerial Neutron Detection of Cosmic-Ray Interactions with the Earth's Surface  

SciTech Connect

We have demonstrated the ability to measure the neutron flux produced by the cosmic-ray interaction with nuclei in the ground surface using aerial neutron detection. High energy cosmic-rays (primarily muons with GeV energies) interact with the nuclei in the ground surface and produce energetic neutrons via spallation. At the air-surface interface, the neutrons produced by spallation will either scatter within the surface material, become thermalized and reabsorbed, or be emitted into the air. The mean free path of energetic neutrons in air can be hundreds of feet as opposed to a few feet in dense materials. As such, the flux of neutrons escaping into the air provides a measure of the surface nuclei composition. It has been demonstrated that this effect can be measured at long range using neutron detectors on low flying helicopters. Radiological survey measurements conducted at Government Wash in Las Vegas, Nevada, have shown that the neutron background from the cosmic-soil interactions is repeatable and directly correlated to the geological data. Government Wash has a very unique geology, spanning a wide variety of nuclide mixtures and formations. The results of the preliminary measurements are presented.

Richard Maurer

2008-09-18T23:59:59.000Z

165

Aerial Neutron Detection of Cosmic-Ray Interactions with the Earth's Surface  

SciTech Connect

We have demonstrated the ability to measure the neutron flux produced by the cosmic-ray interaction with nuclei in the ground surface using aerial neutron detection. High energy cosmic-rays (primarily muons with GeV energies) interact with the nuclei in the ground surface and produce energetic neutrons via spallation. At the air-surface interface, the neutrons produced by spallation will either scatter within the surface material, become thermalized and reabsorbed, or be emitted into the air. The mean free path of energetic neutrons in air can be hundreds of feet as opposed to a few feet in dense materials. As such, the flux of neutrons escaping into the air provides a measure of the surface nuclei composition. It has been demonstrated that this effect can be measured at long range using neutron detectors on low flying helicopters. Radiological survey measurements conducted at Government Wash in Las Vegas, Nevada, have shown that the neutron background from the cosmic-soil interactions is repeatable and directly correlated to the geological data. Government Wash has a very unique geology, spanning a wide variety of nuclide mixtures and formations. The results of the preliminary measurements are presented.

Richard Maurer

2008-09-18T23:59:59.000Z

166

Ultra-High-Energy Cosmic Rays from a Magnetized Strange Star Central Engine for Gamma-Ray Bursts  

E-Print Network (OSTI)

Ultra-high-energy cosmic rays (UHECRs) have been tried to be related to the most varied and powerful sources known in the universe. Gamma-ray bursts (GRBs) are natural candidates. Here, we argue that cosmic rays can be accelerated by large amplitude electromagnetic waves (LAEMWs) when the MHD approximation of the field in the wind generated by the GRB's magnetized central engine breaks down. The central engine considered here is a strange star born with differential rotation from the accretion induced conversion of a neutron star into a strange star in a low-mass X-ray binary system. The LAEMWs generated this way accelerate light ions to the highest energies $E = q\\eta\\Delta\\Phi_{max}$ with an efficiency $\\eta \\sim 10^{-1}$ that accounts for all plausible energy losses. Alternatively, we also consider the possibility that, once formed, the LAEMWs are unstable to creation of a relativistically strong electromagnetic turbulence due to an overturn instability. Under this assumption, a lower limit to the efficien...

Esquivel, O

2008-01-01T23:59:59.000Z

167

PERPENDICULAR DIFFUSION OF COSMIC RAYS FOR A GOLDREICH-SRIDHAR SPECTRUM  

SciTech Connect

Perpendicular diffusion coefficients and mean free paths of cosmic particles are computed for an anisotropic Alfvenic turbulence spectrum corresponding to the Goldreich-Sridhar model by employing an enhanced nonlinear guiding center theory. The calculations are important for understanding cosmic ray propagation in the Galaxy and in the solar system. In addition, the knowledge of diffusion coefficients is also useful for modeling charged particles which experience diffusive shock acceleration in supernova remnants and at interplanetary shock waves. To replace the parallel diffusion coefficient in our equation for the perpendicular diffusion coefficient, we employ different models such as quasilinear results and phenomenological models. The results are compared with those derived earlier. We demonstrate that the choice of the turbulence model as well as the choice of the model for the parallel diffusion coefficient has a strong influence on the perpendicular diffusion coefficient.

Shalchi, A. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Buesching, I.; Schlickeiser, R. [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Lazarian, A., E-mail: andreasm4@yahoo.co [Astronomy Department, University of Wisconsin, Madison, WI 53706 (United States)

2010-12-20T23:59:59.000Z

168

Can Ultra High Energy Cosmic Rays be Evidence for New Particle Physics?  

E-Print Network (OSTI)

Candidate astrophysical acceleration sites capable of producing the highest energy cosmic rays (E > 10^{19.5} eV) appear to be at far greater distances than is compatible with their being known particles. The properties of a new particle which can account for observations are discussed and found to be tightly constrained. In order to travel 100's or 1000's of Mpc through the cosmic microwave background radiation without severe energy loss and yet produce a shower in Earth's atmosphere which is consistent with observations, it must be a hadron with mass of order a few GeV and lifetime greater than about 1 week. A particle with the required properties was identified years ago in the context of supersymmetric theories with a very light gluino. Laboratory experiments do not exclude it, as is discussed briefly.

Farrar, Glennys R S

1998-01-01T23:59:59.000Z

169

Fermi LAT Observation of Diffuse Gamma-Rays Produced through Interactions Between Local Interstellar Matter and High Energy Cosmic Rays  

DOE Green Energy (OSTI)

Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse {gamma}-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200{sup o} to 260{sup o} and latitude |b| from 22{sup o} to 60{sup o}) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system. The contributions of {gamma}-ray point sources and inverse Compton scattering are estimated and subtracted. The residual {gamma}-ray intensity exhibits a linear correlation with the atomic gas column density in energy from 100 MeV to 10 GeV. The measured integrated {gamma}-ray emissivity is (1.63 {+-} 0.05) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} and (0.66 {+-} 0.02) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} above 100 MeV and above 300 MeV, respectively, with an additional systematic error of {approx}10%. The differential emissivity from 100 MeV to 10 GeV agrees with calculations based on cosmic ray spectra consistent with those directly measured, at the 10% level. The results obtained indicate that cosmic ray nuclei spectra within 1 kpc from the solar system in regions studied are close to the local interstellar spectra inferred from direct measurements at the Earth within {approx}10%.

Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U. /Stockholm U., OKC; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, T.H.; /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /Milan Polytechnic /Royal Inst. Tech., Stockholm /Stockholm U., OKC /DAPNIA, Saclay /INFN, Perugia /Perugia U. /NASA, Goddard /Naval Research Lab, Wash., D.C. /George Mason U. /NASA, Goddard /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Stockholm U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /ASDC, Frascati /Naval Research Lab, Wash., D.C. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Trieste /Hiroshima U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Bari U. /INFN, Bari /INFN, Bari; /more authors..

2012-03-30T23:59:59.000Z

170

Low-energy break in the spectrum of Galactic cosmic rays  

E-Print Network (OSTI)

Measurements of the low energy spectrum of Galactic Cosmic Rays (GCR) by detectors at or near the Earth are affected by Solar modulation. To overcome this difficulty, we consider nearby molecular clouds as GCR detectors outside the Solar system. Using gamma-ray observations of the clouds by the Fermi telescope we derive the spectrum of GCRs in the clouds from the observed gamma-ray emission spectrum. We find that the GCR spectrum has a low energy break with the spectral slope hardening by 1.1+/-0.3 at an energy of 9+/-3 GeV. Detection of a low-energy break enables a measurement of GCR energy density in the interstellar space 0.9+/-0.3 eV/cm3.

Neronov, A; Taylor, A M

2011-01-01T23:59:59.000Z

171

Revealing Type Ia supernova physics with cosmic rates and nuclear gamma rays  

E-Print Network (OSTI)

Type Ia supernovae (SNIa) remain mysterious despite their central importance in cosmology and their rapidly increasing discovery rate. The progenitors of SNIa can be probed by the delay time between progenitor birth and explosion as SNIa. The explosions and progenitors of SNIa can be probed by MeV nuclear gamma rays emitted in the decays of radioactive nickel and cobalt into iron. We compare the cosmic star formation and SNIa rates, finding that their different redshift evolution requires a large fraction of SNIa to have large delay times. A delay time distribution of the form t^{-1.0 +/- 0.3} provides a good fit, implying 50% of SNIa explode more than ~ 1 Gyr after progenitor birth. The extrapolation of the cosmic SNIa rate to z = 0 agrees with the rate we deduce from catalogs of local SNIa. We investigate prospects for gamma-ray telescopes to exploit the facts that escaping gamma rays directly reveal the power source of SNIa and uniquely provide tomography of the expanding ejecta. We find large improvements relative to earlier studies by Gehrels et al. in 1987 and Timmes & Woosley in 1997 due to larger and more certain SNIa rates and advances in gamma-ray detectors. The proposed Advanced Compton Telescope, with a narrow-line sensitivity ~ 60 times better than that of current satellites, would, on an annual basis, detect up to ~ 100 SNIa (3 sigma) and provide revolutionary model discrimination for SNIa within 20 Mpc, with gamma-ray light curves measured with ~ 10 sigma significance daily for ~ 100 days. Even more modest improvements in detector sensitivity would open a new and invaluable astronomy with frequent SNIa gamma-ray detections.

Shunsaku Horiuchi; John F. Beacom

2010-06-30T23:59:59.000Z

172

Cosmic ray knee and new physics at the TeV scale  

E-Print Network (OSTI)

We analyze the possibility that the cosmic ray knee appears at an energy threshold where the proton-dark matter cross section becomes large due to new TeV physics. It has been shown that such interactions could break the proton and produce a diffuse gamma ray flux consistent with MILAGRO observations. We argue that this hypothesis implies knees that scale with the atomic mass for the different nuclei, as KASKADE data seem to indicate. We find that to explain the change in the spectral index in the flux from E^{-2.7} to E^{-3.1} the cross section must grow like E^{0.4+\\beta} above the knee, where \\beta=0.3-0.6 parametrizes the energy dependence of the age (\\tau \\propto E^{-\\beta}) of the cosmic rays reaching the Earth. The hypothesis also requires mbarn cross sections (that could be modelled with TeV gravity) and large dark matter densities in the galactic disc (that might be accommodated in a two-component model). We argue that neutrinos would also exhibit a threshold at E=(m_\\chi/m_p)E_{knee}\\approx 10^8 GeV...

Barcelo, Roberto; Mastromatteo, Iacopo

2009-01-01T23:59:59.000Z

173

Amplitude calibration of a digital radio antenna array for measuring cosmic ray air showers  

E-Print Network (OSTI)

Radio pulses are emitted during the development of air showers, where air showers are generated by ultra-high energy cosmic rays entering the Earth's atmosphere. These nanosecond short pulses are presently investigated by various experiments for the purpose of using them as a new detection technique for cosmic particles. For an array of 30 digital radio antennas (LOPES experiment) an absolute amplitude calibration of the radio antennas including the full electronic chain of the data acquisition system is performed, in order to estimate absolute values of the electric field strength for these short radio pulses. This is mandatory, because the measured radio signals in the MHz frequency range have to be compared with theoretical estimates and with predictions from Monte Carlo simulations to reconstruct features of the primary cosmic particle. A commercial reference radio emitter is used to estimate frequency dependent correction factors for each single antenna of the radio antenna array. The expected received power is related to the power recorded by the full electronic chain. Systematic uncertainties due to different environmental conditions and the described calibration procedure are of order 20%.

S. Nehls; A. Hakenjos; M. J. Arts; J. Bluemer; H. Bozdog; W. A. van Cappellen; H. Falcke; A. Haungs; A. Horneffer; T. Huege; P. G. Isar; O. Kroemer

2008-02-28T23:59:59.000Z

174

Observation of an Anisotropy in the Galactic Cosmic Ray arrival direction at 400 TeV with IceCube  

E-Print Network (OSTI)

In this paper we report the first observation in the Southern hemisphere of an energy dependence in the Galactic cosmic ray anisotropy up to a few hundred TeV. This measurement was performed using cosmic ray induced muons recorded by the partially deployed IceCube observatory between May 2009 and May 2010. The data include a total of 33$\\times 10^{9}$ muon events with a median angular resolution of $\\sim3^{\\circ}$ degrees. A sky map of the relative intensity in arrival direction over the Southern celestial sky is presented for cosmic ray median energies of 20 and 400 TeV. The same large-scale anisotropy observed at median energies around 20 TeV is not present at 400 TeV. Instead, the high energy skymap shows a different anisotropy structure including a deficit with a post-trial significance of -6.3$\\sigma$. This anisotropy reveals a new feature of the Galactic cosmic ray distribution, which must be incorporated into theories of the origin and propagation of cosmic rays.

IceCube Collaboration; R. Abbasi; Y. Abdou; T. Abu-Zayyad; M. Ackermann; J. Adams; J. A. Aguilar; M. Ahlers; M. M. Allen; D. Altmann; K. Andeen; J. Auffenberg; X. Bai; M. Baker; S. W. Barwick; R. Bay; J. L. Bazo Alba; K. Beattie; J. J. Beatty; S. Bechet; J. K. Becker; K. -H. Becker; M. L. Benabderrahmane; S. BenZvi; J. Berdermann; P. Berghaus; D. Berley; E. Bernardini; D. Bertrand; D. Z. Besson; D. Bindig; M. Bissok; E. Blaufuss; J. Blumenthal; D. J. Boersma; C. Bohm; D. Bose; S. Böser; O. Botner; A. M. Brown; S. Buitink; K. S. Caballero-Mora; M. Carson; D. Chirkin; B. Christy; F. Clevermann; S. Cohen; C. Colnard; D. F. Cowen; A. H. Cruz Silva; M. V. D'Agostino; M. Danninger; J. Daughhetee; J. C. Davis; C. De Clercq; T. Degner; L. Demirörs; F. Descamps; P. Desiati; G. de Vries-Uiterweerd; T. DeYoung; J. C. Díaz-Vélez; M. Dierckxsens; J. Dreyer; J. P. Dumm; M. Dunkman; J. Eisch; R. W. Ellsworth; O. Engdegård; S. Euler; P. A. Evenson; O. Fadiran; A. R. Fazely; A. Fedynitch; J. Feintzeig; T. Feusels; K. Filimonov; C. Finley; T. Fischer-Wasels; B. D. Fox; A. Franckowiak; R. Franke; T. K. Gaisser; J. Gallagher; L. Gerhardt; L. Gladstone; T. Glüsenkamp; A. Goldschmidt; J. A. Goodman; D. Góra; D. Grant; T. Griesel; A. Groß; S. Grullon; M. Gurtner; C. Ha; A. Haj Ismail; A. Hallgren; F. Halzen; K. Han; K. Hanson; D. Heinen; K. Helbing; R. Hellauer; S. Hickford; G. C. Hill; K. D. Hoffman; B. Hoffmann; A. Homeier; K. Hoshina; W. Huelsnitz; J. -P. Hülß; P. O. Hulth; K. Hultqvist; S. Hussain; A. Ishihara; E. Jacobi; J. Jacobsen; G. S. Japaridze; H. Johansson; K. -H. Kampert; A. Kappes; T. Karg; A. Karle; P. Kenny; J. Kiryluk; F. Kislat; S. R. Klein; J. -H. Köhne; G. Kohnen; H. Kolanoski; L. Köpke; S. Kopper; D. J. Koskinen; M. Kowalski; T. Kowarik; M. Krasberg; G. Kroll; N. Kurahashi; T. Kuwabara; M. Labare; K. Laihem; H. Landsman; M. J. Larson; R. Lauer; J. Lünemann; J. Madsen; A. Marotta; R. Maruyama; K. Mase; H. S. Matis; K. Meagher; M. Merck; P. Mészáros; T. Meures; S. Miarecki; E. Middell; N. Milke; J. Miller; T. Montaruli; R. Morse; S. M. Movit; R. Nahnhauer; J. W. Nam; U. Naumann; D. R. Nygren; S. Odrowski; A. Olivas; M. Olivo; A. O'Murchadha; S. Panknin; L. Paul; C. Pérez de los Heros; J. Petrovic; A. Piegsa; D. Pieloth; R. Porrata; J. Posselt; C. C. Price; P. B. Price; G. T. Przybylski; K. Rawlins; P. Redl; E. Resconi; W. Rhode; M. Ribordy; M. Richman; J. P. Rodrigues; F. Rothmaier; C. Rott; T. Ruhe; D. Rutledge; B. Ruzybayev; D. Ryckbosch; H. -G. Sander; M. Santander; S. Sarkar; K. Schatto; T. Schmidt; A. Schönwald; A. Schukraft; A. Schultes; O. Schulz; M. Schunck; D. Seckel; B. Semburg; S. H. Seo; Y. Sestayo; S. Seunarine; A. Silvestri; G. M. Spiczak; C. Spiering; M. Stamatikos; T. Stanev; T. Stezelberger; R. G. Stokstad; A. Stößl; E. A. Strahler; R. Ström; M. Stüer; G. W. Sullivan; Q. Swillens; H. Taavola; I. Taboada; A. Tamburro; A. Tepe; S. Ter-Antonyan; S. Tilav; P. A. Toale; S. Toscano; D. Tosi; N. van Eijndhoven; J. Vandenbroucke; A. Van Overloop; J. van Santen; M. Vehring; M. Voge; C. Walck; T. Waldenmaier; M. Wallraff; M. Walter; Ch. Weaver; C. Wendt; S. Westerhoff; N. Whitehorn; K. Wiebe; C. H. Wiebusch; D. R. Williams; R. Wischnewski; H. Wissing; M. Wolf; T. R. Wood; K. Woschnagg; C. Xu; D. L. Xu; X. W. Xu; J. P. Yanez; G. Yodh; S. Yoshida; P. Zarzhitsky; M. Zoll

2011-09-05T23:59:59.000Z

175

A prototype system for detecting the radio-frequency pulse associated with cosmic ray air showers  

E-Print Network (OSTI)

The development of a system to detect the radio-frequency (RF) pulse associated with extensive air showers of cosmic rays is described. This work was performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array. A small subset of data (less than 40 out of a total of 600 hours of running time), taken under low-noise conditions, permitted upper limits to be placed on the rate for pulses accompanying showers of energies around $10^{17}$ eV.

Kevin Green; Jonathan L. Rosner; Denis A. Suprun; J. F. Wilkerson

2002-05-03T23:59:59.000Z

176

Solar panels as air Cherenkov detectors for extremely high energy cosmic rays  

E-Print Network (OSTI)

Increasing interest towards the observation of the highest energy cosmic rays has motivated the development of new detection techniques. The properties of the Cherenkov photon pulse emitted in the atmosphere by these very rare particles indicate low-cost semiconductor detectors as good candidates for their optical read-out. The aim of this paper is to evaluate the viability of solar panels for this purpose. The experimental framework resulting from measurements performed with suitably-designed solar cells and large conventional photovoltaic areas is presented. A discussion on the obtained and achievable sensitivities follows.

S. Cecchini; I. D'Antone; L. Degli Esposti; G. Giacomelli; M. Guerra; I. Lax; G. Mandrioli; A. Parretta; A. Sarno; R. Schioppo; M. Sorel; M. Spurio

2000-02-07T23:59:59.000Z

177

Azimuthal modulation of the event rate of cosmic ray extensive air showers by the geomagnetic field  

E-Print Network (OSTI)

The Earth's magnetic field effect on the azimuthal distribution of extensive air showers (EAS) of cosmic rays has been evaluated using a bulk of the Yakutsk array data. The uniform azimuthal distribution of the EAS event rate is rejected at the significance level 10^(-14). Amplitude of the first harmonics of observed distribution depends on zenith angle as A1=0.2*sin^2(theta) and is almost independent of the primary energy; the phase coincides with the magnetic meridian. Basing upon the value of measured effect, the correction factor has been derived for the particle density depending on a geomagnetic parameter of a shower.

A. A. Ivanov; V. P. Egorova; V. A. Kolosov; A. D. Krasilnikov; M. I. Pravdin; I. Ye. Sleptsov

1999-03-23T23:59:59.000Z

178

Cosmic Ray Radiography of the Damaged Cores of the Fukushima Reactors  

E-Print Network (OSTI)

The passage of muons through matter is dominated by the Coulomb interaction with electrons and nuclei. The interaction with the electrons leads to continuous energy loss and stopping of the muons. The interaction with nuclei leads to angle diffusion. Two muon imaging methods that use flux attenuation and multiple Coulomb scattering of cosmic-ray muons are being studied as tools for diagnosing the damaged cores of the Fukushima reactors. Here we compare these two methods. We conclude that the scattering method can provide detailed information about the core. Attenuation has low contrast and little sensitivity to the core.

Konstantin Borozdin; Steven Greene; Zarija Luki?; Edward Cas Milner; Haruo Miyadera; Christopher Morris; John Perry

2012-09-13T23:59:59.000Z

179

The Chicagoland Observatory Underground for Particle Physics cosmic ray veto system  

SciTech Connect

A photomultiplier (PMT) readout system has been designed for use by the cosmic ray veto systems of two warm liquid bubble chambers built at Fermilab by the Chicagoland Observatory Underground for Particle Physics (COUPP) collaboration. The systems are designed to minimize the infrastructure necessary for installation. Up to five PMTs can be daisy-chained on a single data link using standard Category 5 network cable. The cables is also serve distribute to low voltage power. High voltage is generated locally on each PMT base. Analog and digital signal processing is also performed locally. The PMT base and system controller design and performance measurements are presented.

Crisler, M.; Hall, J.; Ramberg, E.; Kiper, T.; /Fermilab

2010-11-01T23:59:59.000Z

180

30TH INTERNATIONAL COSMIC RAY CONFERENCE Search for 1-100 GeV Emission from Gamma-Ray Bursts Using Milagro  

E-Print Network (OSTI)

30TH INTERNATIONAL COSMIC RAY CONFERENCE Search for 1-100 GeV Emission from Gamma-Ray Bursts Using one hundred gamma-ray bursts (GRBs) detected since the beginning of 2000 by BATSE, BeppoSax, HETE-2 spectra of gamma-ray bursts peak around a few hundred keV, EGRET has ob- served photons in the GeV energy

California at Santa Cruz, University of

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181

Power of Turbulent Reconnection: Star Formation, Acceleration of Cosmic Rays, Heat Transfer, Flares and Gamma Ray Bursts  

E-Print Network (OSTI)

Turbulence is ubiquitous in astrophysical fluids. Therefore it is necessary to study magnetic reconnection in turbulent environments. The model of fast turbulent reconnection proposed in Lazarian & Vishniac 1999 has been successfully tested numerically and it suggests numerous astrophysical implications. Those include a radically new possibility of removing magnetic field from collapsing clouds which we termed "reconnection diffusion", acceleration of cosmic rays within shrinking filaments of reconnected magnetic fields, flares of reconnection, from solar flares to much stronger ones which can account for gamma ray bursts. In addition, the model reveals a very intimate relation between magnetic reconnection and properties of strong turbulence, explaining how turbulent eddies can transport heat in magnetized plasmas. This is a small fraction the astrophysical implications of the quantitative insight into the fundamental process of magnetic reconnection in turbulent media.

Lazarian, A

2011-01-01T23:59:59.000Z

182

Neutrino background flux from sources of ultrahigh-energy cosmic-ray nuclei  

Science Conference Proceedings (OSTI)

Motivated by Pierre Auger Observatory results favoring a heavy nuclear composition for ultrahigh-energy (UHE) cosmic rays, we investigate implications for the cumulative neutrino background. The requirement that nuclei not be photodisintegrated constrains their interactions in sources, therefore limiting neutrino production via photomeson interactions. Assuming a dN{sub CR}/dE{sub CR{proportional_to}}E{sub CR}{sup -2} injection spectrum and photodisintegration via the giant dipole resonance, the background flux of neutrinos is lower than E{sub {nu}}{sup 2{Phi}}{sub {nu}{approx}1}0{sup -9} GeV cm{sup -2} s{sup -1} sr{sup -1} if UHE nuclei ubiquitously survive in their sources. This is smaller than the analogous Waxman-Bahcall flux for UHE protons by about 1 order of magnitude and is below the projected IceCube sensitivity. If IceCube detects a neutrino background, it could be due to other sources, e.g., hadronuclear interactions of lower-energy cosmic rays; if it does not, this supports our strong restrictions on the properties of sources of UHE nuclei.

Murase, Kohta [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, 606-8502 (Japan); CCAPP, Ohio State University, Columbus, Ohio 43210 (United States); Beacom, John F. [CCAPP, Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Department of Astronomy, Ohio State University, Columbus, Ohio 43210 (United States)

2010-06-15T23:59:59.000Z

183

The Evolution of Li6 in Standard Cosmic-Ray Nucleosynthesis  

E-Print Network (OSTI)

We review the Galactic chemical evolution of Li6 and compare these results with recent observational determinations of the lithium isotopic ratio. In particular, we concentrate on so-called standard Galactic cosmic-ray nucleosynthesis in which Li, Be, and B are produced (predominantly) by the inelastic scattering of accelerated protons and \\alpha's off of CNO nuclei in the ambient interstellar medium. If O/Fe is constant at low metallicities, then the Li6 vs Fe/H evolution-as well as Be and B vs Fe/H-has difficulty in matching the observations. However, recent determinations of Population II oxygen abundances, as measured via OH lines, indicate that O/Fe increases at lower metallicity; if this trend is confirmed, then the Li6 evolution in a standard model of cosmic-ray nucleosynthesis is consistent with the data. We also show that another key indicator of Li6BeB origin is the Li6/Be ratio which also fits the available data if O/Fe is not constant at low metallicity. Finally we note that Li6 evolution in this scenario can strongly constrain the degree to which Li6 and Li7 are depleted in halo stars.

Brian D. Fields; Keith A. Olive

1998-11-11T23:59:59.000Z

184

Implications to Sources of Ultra-high-energy Cosmic Rays from their Arrival Distribution  

E-Print Network (OSTI)

We estimate the local number density of sources of ultra-high-energy cosmic rays (UHECRs) based on the statistical features of their arrival direction distribution. We calculate the arrival distributions of protons above $10^{19}$ eV taking into account their propagation process in the Galactic magnetic field and a structured intergalactic magnetic field, and statistically compare those with the observational result of the Pierre Auger Observatory. The anisotropy in the arrival distribution at the highest energies enables us to estimate the number density of UHECR sources as $\\sim 10^{-4} {\\rm Mpc}^{-3}$ assuming the persistent activity of UHECR sources. We compare the estimated number density of UHECR sources with the number densities of known astrophysical objects. This estimated number density is consistent with the number density of Fanaroff-Reily I galaxies. We also discuss the reproducability of the observed {\\it isotropy} in the arrival distribution above $10^{19}$ eV. We find that the estimated source model cannot reproduce the observed isotropy. However, the observed isotropy can be reproduced with the number density of $10^{-2}$-$10^{-3} {\\rm Mpc}^{-3}$. This fact indicates the existence of UHECR sources with a maximum acceleration energy of $\\sim 10^{19}$ eV whose number density is an order of magnitude more than that injecting the highest energy cosmic rays.

Hajime Takami; Katsuhiko Sato

2008-07-22T23:59:59.000Z

185

KASCADE-Grande measurements of energy spectra for elemental groups of cosmic rays  

E-Print Network (OSTI)

The KASCADE-Grande experiment, located at KIT-Karlsruhe, Germany, consists of a large scintillator array for measurements of charged particles, N_ch, and of an array of shielded scintillation counters used for muon counting, N_mu. KASCADE-Grande is optimized for cosmic ray measurements in the energy range 10 PeV to 1000 PeV, thereby enabling the verification of a knee in the iron spectrum expected at approximately 100 PeV. Exploring the composition in this energy range is of fundamental importance for understanding the transition from galactic to extragalactic cosmic rays. Following earlier studies of elemental spectra reconstructed in the knee energy range from KASCADE data, we have now extended these measurements to beyond 100 PeV. By analysing the two-dimensional shower size spectrum N_ch vs. N_mu, we reconstruct the energy spectra of different mass groups by means of unfolding methods. The procedure and its results, giving evidence for a knee-like structure in the spectrum of iron nuclei, will be presente...

Fuhrmann, D; Arteaga-Velazquez, J C; Bekk, K; Bertaina, M; Bluemer, J; Bozdog, H; Brancus, I M; Cantoni, E; Chiavassa, A; Cossavella, F; Curcio, C; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Engler, J; Fuchs, B; Gils, H J; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hoerandel, J R; Huber, D; Huege, T; Kampert, K -H; Kang, D; Klages, H O; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Mayer, H J; Melissas, M; Milke, J; Mitrica, B; Morello, C; Oehlschlaeger, J; Ostapchenko, S; Palmieri, N; Petcu, M; Pierog, T; Rebel, H; Roth, M; Schieler, H; Schoo, S; Schroeder, F G; Sima, O; Toma, G; Trinchero, G C; Ulrich, H; Weindl, A; Wochele, D; Wochele, J

2013-01-01T23:59:59.000Z

186

On the significance of the observed clustering of ultra-high energy cosmic rays  

E-Print Network (OSTI)

Three pairs of possibly correlated ultra-high energy cosmic ray events were reported by Hayashida et al (1996). Here we calculate the propagation of the corresponding particles through both the intergalactic and galactic magnetic fields. The large scale disc and halo magnetic components are approximated by the models of Stanev (1997). The intergalactic magnetic field intensity is modulated by the actual density of luminous matter along the corresponding lines of sight, calculated from the CfA redshift catalogue (Huchra et al, 1995). The results indicate that, if the events of each pair had a common source and were simultaneously produced, they either originated inside the galactic halo or otherwise very unlikely events were observed. On the other hand, an estimate of the arrival probability of ultra-high energy cosmic rays, under the assumption that the distribution of luminous matter in the nearby universe traces the distribution of the sources of the particles and intensity of the intergalactic magnetic field, suggests that the pairs are chance clusterings.

Gustavo A. Medina Tanco

1998-01-08T23:59:59.000Z

187

The Large Scale Cosmic-Ray Anisotropy as Observed with Milagro  

E-Print Network (OSTI)

Results are presented of a harmonic analysis of the large scale cosmic-ray anisotropy as observed by the Milagro observatory. We show a two-dimensional display of the sidereal anisotropy projections in right ascension generated by the fitting of three harmonics to 18 separate declination bands. The Milagro observatory is a water Cherenkov detector located in the Jemez mountains near Los Alamos, New Mexico. With a high duty cycle and large field-of-view, Milagro is an excellent instrument for measuring this anisotropy with high sensitivity at TeV energies. The analysis is conducted using a seven year data sample consisting of more than 95 billion events. We observe an anisotropy with a magnitude around 0.1% for cosmic rays with a median energy of 6 TeV. The dominant feature is a deficit region of depth (-2.85 +/- 0.06 stat. +/- 0.08 syst.)x10^(-3) in the direction of the Galactic North Pole with a range in declination of -10 to 45 degrees and 150 to 225 degrees in right ascension. We observe a steady increase ...

Abdo, A A; Aune, T; Berley, D; Casanova, S; Chen, C; Dingus, B L; Ellsworth, R W; Fleysher, L; Fleysher, R; González, M M; Goodman, J A; Hoffman, C M; Hopper, B; Hüntemeyer, P H; Kolterman, B E; Lansdell, C P; Linnemann, J T; McEnery, J E; Mincer, A I; Némethy, P; Noyes, D; Ryan, J M; Parkinson, P M Saz; Shoup, A; Sinnis, G; Smith, A J; Sullivan, G W; Vasileiou, V; Walker, G P; Williams, D A; Yodh, G B

2008-01-01T23:59:59.000Z

188

X-RAY STRIPES IN TYCHO'S SUPERNOVA REMNANT: SYNCHROTRON FOOTPRINTS OF A NONLINEAR COSMIC-RAY-DRIVEN INSTABILITY  

Science Conference Proceedings (OSTI)

High-resolution Chandra observations of Tycho's supernova remnant (SNR) have revealed several sets of quasi-steady, high-emissivity, nearly parallel X-ray stripes in some localized regions of the SNR. These stripes are most likely the result of cosmic-ray (CR) generated magnetic turbulence at the SNR blast wave. However, for the amazingly regular pattern of these stripes to appear, simultaneous action of a number of shock-plasma phenomena is required, which is not predicted by most models of magnetic field amplification. A consistent explanation of these stripes yields information on the complex nonlinear plasma processes connecting efficient CR acceleration and magnetic field fluctuations in strong collisionless shocks. The nonlinear diffusive shock acceleration (NL-DSA) model described here, which includes magnetic field amplification from a CR-current-driven instability, does predict stripes consistent with the synchrotron observations of Tycho's SNR. We argue that the local ambient mean magnetic field geometry determines the orientation of the stripes and therefore it can be reconstructed with the high-resolution X-ray imaging. The estimated maximum energy of the CR protons responsible for the stripes is {approx}10{sup 15} eV. Furthermore, the model predicts that a specific X-ray polarization pattern, with a polarized fraction {approx}50%, accompanies the stripes, which can be tested with future X-ray polarimeter missions.

Bykov, Andrei M.; Osipov, Sergei M.; Uvarov, Yury A. [Ioffe Physical-Technical Institute, St. Petersburg (Russian Federation); Ellison, Donald C. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Pavlov, George G., E-mail: byk@astro.ioffe.ru, E-mail: osm@astro.ioffe.ru, E-mail: uv@astro.ioffe.ru, E-mail: don_ellison@ncsu.edu, E-mail: pavlov@astro.psu.edu [525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States)

2011-07-10T23:59:59.000Z

189

Cosmic ray spectral hardening due to dispersion of source injection spectra  

E-Print Network (OSTI)

The cosmic ray (CR) energy spectra measured with ATIC, CREAM and PAMELA showed that there is remarkable hardening for rigidity of several hundred GV. We propose that this hardening is due to the superposition of spectra from a population of sources, e.g., supernova remnants (SNRs), whose injection spectral indices have a dispersion. Adopting proper model parameters the observational data can be well explained. It is interesting that the injection source parameters are similar with that derived from gamma-ray observations of SNRs, which may support the SNR-origin of CRs. Furthermore this mechanism provides an alternative explanation of the "ankle-cutoff" structure of the ultra high energy CR spectra.

Yuan, Qiang; Bi, Xiao-Jun

2011-01-01T23:59:59.000Z

190

Molecular Beam Dumps as Tracers of Hadronic Cosmic Ray Sources the Case of SNR IC443  

E-Print Network (OSTI)

The gamma-ray & neutrino visibility of cosmic ray (CR) accelerators will be dramatically increased by the presence of molecular material abutting such sites due to the increased probability of pion production -- and, in the case of neutral pions, subsequent gamma-decay. This was recognized by Pinkau, Montmerle, and Black & Fazio, and others in the 1970's. In an effort to examine the long-standing -- but unproven -- conjecture that galactic supernova remnants (SNRs) are indeed the sites of nucleonic CR acceleration to 0) mm wavelength data from the compilation of Dame, Hartmann & Thaddeus (2001), at the best estimates of the various SNR distances. We outline the overall correlative study and examine the interesting case of SNR IC443, a likely accelerator of CR nuclei.

Butt, Y M; Combi, J A; Dame, T M; Romero, G E; Butt, Yousaf M.; Torres, Diego F.; Combi, Jorge A.; Dame, Thomas; Romero, Gustavo E.

2002-01-01T23:59:59.000Z

191

Molecular Beam Dumps as Tracers of Hadronic Cosmic Ray Sources: the Case of SNR IC443  

E-Print Network (OSTI)

The gamma-ray & neutrino visibility of cosmic ray (CR) accelerators will be dramatically increased by the presence of molecular material abutting such sites due to the increased probability of pion production -- and, in the case of neutral pions, subsequent gamma-decay. This was recognized by Pinkau, Montmerle, and Black & Fazio, and others in the 1970's. In an effort to examine the long-standing -- but unproven -- conjecture that galactic supernova remnants (SNRs) are indeed the sites of nucleonic CR acceleration to Hartman et al.,1999), and molecular clouds, at low Galactic latitudes (|b|0) mm wavelength data from the compilation of Dame, Hartmann & Thaddeus (2001), at the best estimates of the various SNR distances. We outline the overall correlative study and examine the interesting case of SNR IC443, a likely accelerator of CR nuclei.

Yousaf M. Butt; Diego F. Torres; Jorge A. Combi; Thomas M. Dame; Gustavo E. Romero

2002-06-09T23:59:59.000Z

192

On the plasma temperature in supernova remnants with cosmic-ray modified shocks  

E-Print Network (OSTI)

Context: Multiwavelength observations of supernova remnants can be explained within the framework of the diffusive shock acceleration theory, which allows effective conversion of the explosion energy into cosmic rays. Although the models of nonlinear shocks describe reasonably well the nonthermal component of emission, certain issues, including the heating of the thermal plasma and the related X-ray emission, remain still open. Aims: To discuss how the evolution and structure of supernova remnants is affected by strong particle acceleration at the forward shock. Methods: Analytical estimates combined with detailed discussion of the physical processes. Results: The overall dynamics is shown to be relatively insensitive to the amount of particle acceleration, but the post-shock gas temperature can be reduced to a relatively small multiple, even as small as six times, the ambient temperature with a very weak dependence on the shock speed. This is in marked contrast to pure gas models where the temperature is ins...

O'Connor-Drury, L; Malyshev, D; Gabici, S

2008-01-01T23:59:59.000Z

193

The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays  

Science Conference Proceedings (OSTI)

Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.

Abreu, P.; /Lisbon, LIFEP /Lisbon, IST; Aglietta, M.; /Turin Observ. /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab; Allard, D.; /APC, Paris; Allekotte, I.; /Centro Atomico Bariloche /Balseiro Inst., San Carlos de Bariloche; Allen, J.; /New York U.; Alvarez Castillo, J.; /Mexico U.; Alvarez-Muniz, J.; /Santiago de Compostela U.; Ambrosio, M.; /Naples U. /INFN, Naples; Aminaei, A.; /Nijmegen U., IMAPP; Anchordoqui, L.; /Wisconsin U., Milwaukee /Lisbon, LIFEP /Lisbon, IST

2011-01-01T23:59:59.000Z

194

Gamma-Ray Bursts as a Cosmic Window for Galaxy Evolution  

E-Print Network (OSTI)

Present knowledge indicates that gamma-ray bursts are linked with massive stars. They will become invaluable probes of the early universe and galaxy formation. In the future, it will be possible to use gamma-ray bursts for two purposes: 1) to probe the history of massive star formation in the Universe by the rate of occurence of gamma-ray bursts, and 2) for the study of galaxy evolution at all lookback times by determining the nature of the galaxy hosts. Because gamma-rays are not attenuated by intervening dust and gas, the selection of the cosmic sites of massive star formation by this method is less affected by the biases associated with optical-uv surveys (e.g. UV-dropout techniques). Infrared and sub-millimeter follow up studies of the hosts of gamma-ray bursts may: 1) reveal a putative population of reddened ($R-K \\geq 4$) galaxies at high redshifts, and 2) detect very massive stars (population III) formed at $z \\geq$ 5.

I. F. Mirabel; D. B. Sanders; E. Le Floc'h

2000-04-03T23:59:59.000Z

195

DETECTION OF THE COSMIC {gamma}-RAY HORIZON FROM MULTIWAVELENGTH OBSERVATIONS OF BLAZARS  

SciTech Connect

The first statistically significant detection of the cosmic {gamma}-ray horizon (CGRH) that is independent of any extragalactic background light (EBL) model is presented. The CGRH is a fundamental quantity in cosmology. It gives an estimate of the opacity of the universe to very high energy (VHE) {gamma}-ray photons due to photon-photon pair production with the EBL. The only estimations of the CGRH to date are predictions from EBL models and lower limits from {gamma}-ray observations of cosmological blazars and {gamma}-ray bursts. Here, we present homogeneous synchrotron/synchrotron self-Compton (SSC) models of the spectral energy distributions of 15 blazars based on (almost) simultaneous observations from radio up to the highest energy {gamma}-rays taken with the Fermi satellite. These synchrotron/SSC models predict the unattenuated VHE fluxes, which are compared with the observations by imaging atmospheric Cherenkov telescopes. This comparison provides an estimate of the optical depth of the EBL, which allows us a derivation of the CGRH through a maximum likelihood analysis that is EBL-model independent. We find that the observed CGRH is compatible with the current knowledge of the EBL.

Dominguez, A.; Siana, B. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Finke, J. D. [U.S. Naval Research Laboratory, Space Science Division, Code 7653, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Prada, F. [Campus of International Excellence UAM-CSIC, Cantoblanco, E-28049 Madrid (Spain); Primack, J. R. [Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Kitaura, F. S. [Leibniz-Institut fuer Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Paneque, D., E-mail: albertod@ucr.edu [Kavli Institute for Particle Astrophysics and Cosmology, SLAC, Stanford University, Stanford, CA 94305 (United States)

2013-06-10T23:59:59.000Z

196

LOWER LIMITS ON ULTRAHIGH-ENERGY COSMIC RAY AND JET POWERS OF TeV BLAZARS  

Science Conference Proceedings (OSTI)

Lower limits on the power emitted in ultrahigh-energy cosmic rays (UHECRs), which are assumed to be protons with energy {approx}> 10{sup 17}-10{sup 20} eV, are derived for TeV blazars with the assumption that the observed TeV {gamma}-rays are generated due to interactions of these protons with cosmic microwave photons. The limits depend on the spectrum of the injected UHECR protons. While for a -2.2 injection spectrum the lower limits on the powers emitted in UHECRs by 1ES 0229+200, 1ES 1101-232, and 1ES 0347-121 are lower than their respective synchrotron luminosities ({approx}10{sup 46} erg s{sup -1}), in the case of 1ES 1426+428 it exceeds the corresponding synchrotron luminosity by up to an order of magnitude. The proposed Auger North Observatory should be able to detect 4 Multiplication-Sign 10{sup 19} eV cosmic-ray (CR) protons from 1ES 1426+428 within a few years of operation and test the TeV {gamma}-ray production model by UHECR energy losses while propagating along the line of sight or constrain the intergalactic magnetic field to be larger than {approx}10{sup -16} G in case of no detection. The lower limits on the apparent-isotropic jet power from accelerated 10{sup 10}-10{sup 20} eV proton spectra in the blazar jet is of the order of the Eddington luminosity of a 10{sup 9} M{sub Sun} black hole for a CR injection spectrum -2.2 or harder for all blazars considered except for 1ES 1426+428. In the case of the latter, the apparent-isotropic jet power exceeds the Eddington luminosity by an order of magnitude. For an injection spectrum softer than -2.2, as is required to fit the observed CR data above {approx}10{sup 17}-10{sup 18} eV, the Eddington luminosity is exceeded by the lower limits on the jet power for all blazars considered.

Razzaque, Soebur [School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030 (United States); Dermer, Charles D.; Finke, Justin D., E-mail: srazzaqu@gmu.edu [Space Science Division, US Naval Research Laboratory, Washington, DC 20375 (United States)

2012-02-01T23:59:59.000Z

197

Summary of the cosmic-ray intensity during the solar-terrestrial events of 16 February and 24-28 April 1984  

SciTech Connect

A brief summary is presented of the ground-level solar cosmic-ray event on 16 February 1984 and of the Forbush decrease in cosmic-ray intensity associate with the flare of 24 April and subsequent geomagnetic disturbance on 26-28 April 1984.

Shea, M.A.

1987-07-01T23:59:59.000Z

198

Modeling the gamma-ray emission produced by runaway cosmic rays in the environment of RX J1713.7-3946  

E-Print Network (OSTI)

Diffusive shock acceleration in supernova remnants is the most widely invoked paradigm to explain the Galactic cosmic ray spectrum. Cosmic rays escaping supernova remnants diffuse in the interstellar medium and collide with the ambient atomic and molecular gas. From such collisions gamma-rays are created, which can possibly provide the first evidence of a parent population of runaway cosmic rays. We present model predictions for the GeV to TeV gamma-ray emission produced by the collisions of runaway cosmic rays with the gas in the environment surrounding the shell-type supernova remnant RX J1713.7-3946. The spectral and spatial distributions of the emission, which depend upon the source age, the source injection history, the diffusion regime and the distribution of the ambient gas, as mapped by the LAB and NANTEN surveys, are studied in detail. In particular, we find for the region surrounding RX J1713-3946, that depending on the energy one is observing at, one may observe startlingly different spectra or may...

Casanova, S; Aharonian, F A; Fukui, Y; Gabici, S; Kawamura, A; Onishi, T; Rowell, G; Torii, K; Yamamoto, H

2010-01-01T23:59:59.000Z

199

The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars  

E-Print Network (OSTI)

Two classes of X-ray pulsars, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have been recognized in the last decade as the most promising candidates for being magnetars: isolated neutron stars powered by magnetic energy. I review the observational properties of these objects, focussing on the most recent results, and their interpretation in the magnetar model. Alternative explanations, in particular those based on accretion from residual disks, are also considered. The possible relations between these sources and other classes of neutron stars and astrophysical objects are also discussed.

Mereghetti, Sandro

2008-01-01T23:59:59.000Z

200

The strongest cosmic magnets: Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars  

E-Print Network (OSTI)

Two classes of X-ray pulsars, the Anomalous X-ray Pulsars and the Soft Gamma-ray Repeaters, have been recognized in the last decade as the most promising candidates for being magnetars: isolated neutron stars powered by magnetic energy. I review the observational properties of these objects, focussing on the most recent results, and their interpretation in the magnetar model. Alternative explanations, in particular those based on accretion from residual disks, are also considered. The possible relations between these sources and other classes of neutron stars and astrophysical objects are also discussed.

Sandro Mereghetti

2008-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Constraining the origin of the rising cosmic ray positron fraction with the boron-to-carbon ratio  

E-Print Network (OSTI)

The rapid rise in the cosmic ray positron fraction above 10 GeV, as measured by PAMELA and AMS, suggests the existence of nearby primary sources of high energy positrons, such as pulsars or annihilating/decaying dark matter. In contrast, the spectrum of secondary positrons produced through the collisions of cosmic rays in the interstellar medium is predicted to fall rapidly with energy, and thus is unable to account for the observed rise. It has been proposed, however, that secondary positrons could be produced and then accelerated in nearby supernova remnants, potentially explaining the observed rise, without the need of primary positron sources. Yet, if secondary positrons are accelerated in such shocks, other secondary cosmic ray species (such as boron nuclei, and antiprotons) will also be accelerated, leading to rises in the boron-to-carbon and antiproton-to-proton ratios. The measurements of the boron-to-carbon ratio by the PAMELA and AMS collaborations, however, show no sign of such a rise. With this new data in hand, we revisit the secondary acceleration scenario for the rising positron fraction. Assuming that the same supernova remnants accelerate both light nuclei (protons, helium) and heavier cosmic ray species, we find that no more than ~25% of the observed rise in the positron fraction can result from this mechanism (at the 95% confidence level)

Ilias Cholis; Dan Hooper

2013-12-10T23:59:59.000Z

202

Probing the Climatological Impact of a Cosmic Ray-Cloud Connection through Low-Frequency Radio Observations  

E-Print Network (OSTI)

It has been proposed that cosmic ray events could have a causal relationship with cloud formation rates. Given the weak constraints on the role that cloud formation plays in climate forcing it is essential to understand the role such a relationship could have in shaping the Earth's climate. This issue has been previously investigated in the context of the long-term effect of cosmic ray events on climate. However, in order to establish whether or not such a relationship exists, measurements of short-timescale solar events, individual cosmic ray events, and spatially correlated cloud parameters could be of great significance. Here we propose such a comparison using observations from a pair of radio telescopes arrays, the Long Wavelength Array (LWA) and the Eight-meter-wavelength Transient Array (ETA). These low-frequency radio arrays have a unique ability to simultaneously conduct solar, ionospheric and cosmic rays observations and are thus ideal for such a comparison. We will outline plans for a comparison usi...

Magee, Nathan

2011-01-01T23:59:59.000Z

203

Suprathermal particle addition to solar wind pressure: possible influence on magnetospheric transmissivity of low energy cosmic rays?  

E-Print Network (OSTI)

Energetic (suprathermal) solar particles, accelerated in the interplanetary medium, contribute to the solar wind pressure, in particular during high solar activity periods. We estimated the effect of the increase of solar wind pressure due to suprathermal particles on magnetospheric transmissivity of galactic cosmic rays in the case of one recent solar event.

Bobik, P; Consolandi, C; Della Torre, S; Gervasi, M; Grandi, D; Kudela, K; La Vacca, G; Mallamaci, M; Pensotti, S; Rancoita, P G; Rozza, D; Tacconi, M

2013-01-01T23:59:59.000Z

204

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 Influence of geomagnetic effects on large scale anisotropy searches  

E-Print Network (OSTI)

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 Influence of geomagnetic effects on large://www.auger.org/archive/authors 2011 05.html) auger spokespersons@fnal.gov Abstract: We discuss the influence of the geomagnetic field Detector array of the Pierre Auger Observatory. The geomagnetic field induces a modulation of the energy

Hörandel, Jörg R.

205

Performances of linseed oil-free bakelite RPC prototypes with cosmic ray muons  

E-Print Network (OSTI)

A comparative study has been performed on Resistive Plate Chambers (RPC) made of two different grades of bakelite paper laminates, produced and commercially available in India. The chambers, operated in the streamer mode using argon, tetrafluroethane and isobutane in 34:59:7 mixing ratio, are tested for the efficiency and the stability with cosmic rays. A particular grade of bakelite (P-120, NEMA LI-1989 Grade XXX), used for high voltage insulation in humid conditions, was found to give satisfactory performance with stable efficiency of > 96% continuously for more than 130 days. A thin coating of silicone fluid on the inner surfaces of the bakelite RPC is found to be necessary for operation of the detector.

S. Biswas; S. Bhattacharya; S. Bose; S. Chattopadhyay; S. Saha; M. K. Sharan; Y. P. Viyogi

2009-07-17T23:59:59.000Z

206

First results from the MACRO (Monopole, Astophysics, Cosmic Ray Observatory) detector at the Gran Sasso Laboratory  

Science Conference Proceedings (OSTI)

The MACRO (Monopole, Astrophysics, Cosmic Ray Observatory) detector which is being installed at the underground Gran Sasso Laboratory (LNGS) is described in detail. The performance of the detector's first supermodule ({approximately}800 m{sup 2}sr), which had its initial data run from February 27 to May 30, 1989, is reported. About 245,000 muon triggers were recorded during this first run. Preliminary results are presented on: the measured vertical muon flux; the detection features of MACRO as a high energy muon and muon neutrino telescope; the measured lateral spread and multiplicity distributions of muon bundles; a search for GUT magnetic monopoles; a search for electron anti-neutrinos from stellar collapses. In addition, there are results obtained in conjunction with the EAS-TOP detector located on top of the Gran Sasso mountain. 24 refs., 22 figs.

Calicchio, M.; De Cataldo, G.; De Marzo, C.; Erriquez, O.; Favuzzi, C.; Giglietto, N.; Nappi, E.; Spinelli, P.; Cecchini, S.; D'Antone, I.; Giacomelli, G.; Mandrioli, G.; Margiotta-Neri, A.; Matteuzzi, P.; Pal, B.; Patrizii, L.; Predieri, F.; Sanzani, G.L.; Serra, P.; Spurio, M.; Ahlen, S.P.; Ficenec, D.; Hazen, E.; Klein, S.; Levin, D.; Marin, A.; Stone, J.L.; Sulak, L.R.; Worstell, W.; Barish, B.; Coutu, S.; Hong, J.T.; Liu, G

1989-01-01T23:59:59.000Z

207

New Measurement of the Cosmic-Ray Positron Fraction from 5 to 15 GeV  

E-Print Network (OSTI)

We present a new measurement of the cosmic-ray positron fraction at energies between 5 and 15 GeV with the balloon-borne HEAT-pbar instrument in the spring of 2000. The data presented here are compatible with our previous measurements, obtained with a different instrument. The combined data from the three HEAT flights indicate a small positron flux of non-standard origin above 5 GeV. We compare the new measurement with earlier data obtained with the HEAT-e+- instrument, during the opposite epoch of the solar cycle, and conclude that our measurements do not support predictions of charge sign dependent solar modulation of the positron abundance at 5 GeV.

J. J. Beatty; A. Bhattacharyya; C. Bower; S. Coutu; M. A. DuVernois; S. McKee; S. A. Minnick; D. Muller; J. Musser; S. Nutter; A. W. Labrador; M. Schubnell; S. Swordy; G. Tarle; A. Tomasch

2004-12-09T23:59:59.000Z

208

Ultra high energy neutrino-nucleon cross section from cosmic ray experiments and neutrino telescopes  

E-Print Network (OSTI)

We deduce the cosmogenic neutrino flux by jointly analysing ultra high energy cosmic ray data from HiRes-I and II, AGASA and the Pierre Auger Observatory. We make two determinations of the neutrino flux by using a model-dependent method and a model-independent method. The former is well-known, and involves the use of a power-law injection spectrum. The latter is a regularized unfolding procedure. We then use neutrino flux bounds obtained by the RICE experiment to constrain the neutrino-nucleon inelastic cross section at energies inaccessible at colliders. The cross section bounds obtained using the cosmogenic fluxes derived by unfolding are the most model-independent bounds to date.

V. Barger; Patrick Huber; Danny Marfatia

2006-06-29T23:59:59.000Z

209

Searches for cosmic-ray electron anisotropies with the Fermi Large Area Telescope  

SciTech Connect

The Large Area Telescope on board the Fermi satellite (Fermi LAT) detected more than 1.6x10{sup 6} cosmic-ray electrons/positrons with energies above 60 GeV during its first year of operation. The arrival directions of these events were searched for anisotropies of angular scale extending from {approx}10 deg. up to 90 deg., and of minimum energy extending from 60 GeV up to 480 GeV. Two independent techniques were used to search for anisotropies, both resulting in null results. Upper limits on the degree of the anisotropy were set that depended on the analyzed energy range and on the anisotropy's angular scale. The upper limits for a dipole anisotropy ranged from {approx}0.5% to {approx}10%.

Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Buehler, R.; Cameron, R. A.; Charles, E.; Chiang, J.; Claus, R.; Digel, S. W.; Couto e Silva, E. do; Drell, P. S.; Dubois, R.; Focke, W. B.; Funk, S.; Glanzman, T.; Godfrey, G. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305 (United States)

2010-11-01T23:59:59.000Z

210

Recent Results from RHIC&Some Lessons for Cosmic-RayPhysicists  

SciTech Connect

The Relativistic Heavy Ion Collider (RHIC) studies nuclear matter under a variety of conditions. Cold nuclear matter is probed with deuteron-gold collisions, while hot nuclear matter (possibly a quark-gluon plasma (QGP)) is created in heavy-ion collisions. The distribution of spin in polarized nucleons is measured with polarized proton collisions, and photoproduction is studied using the photons that accompany heavy nuclei. The deuteron-gold data shows less forward particle production than would be expected from a superposition of pp collisions, as expected due to saturation/shadowing. Particle production in AA collisions is well described by a model of an expanding fireball in thermal equilibrium. Strong hydrodynamic flow and jet quenching shows that the produced matter interacts very strongly. These phenomena are consistent with new non-perturbative interactions near the transition temperature to the QGP. This report discusses these results, and their implications for cosmic-ray physicists.

Klein, Spencer R.

2006-10-01T23:59:59.000Z

211

STABLE HEATING OF CLUSTER COOLING FLOWS BY COSMIC-RAY STREAMING  

SciTech Connect

We study heating of cool cores in galaxy clusters by cosmic-ray (CR) streaming using numerical simulations. In this model, CRs are injected by the central active galactic nucleus (AGN) and move outward with Alfven waves. The waves are excited by the streaming itself and become nonlinear. If magnetic fields are large enough, CRs can prevail in and heat the entire core because of a large Alfven velocity. We find that the CR streaming can stably heat both high- and low-temperature clusters for a long time without the assistance of thermal conduction, and it can prevent the development of massive cooling flows. If there is even a minor contribution from thermal conduction, the heating can be stabilized further. We discuss the reason for the stability and indicate that the CR pressure is insensitive to changes in the intracluster medium (ICM) and that the density dependence of the heating term is similar to that of radiative cooling.

Fujita, Yutaka [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan); Ohira, Yutaka, E-mail: fujita@vega.ess.sci.osaka-u.ac.jp [Theory Centre, Institute of Particle and Nuclear Studies, KEK, 1-1 Oho, Tsukuba 305-0801 (Japan)

2011-09-10T23:59:59.000Z

212

Commissioning of the ATLAS Trigger Event Selection with Single?Beam and Cosmic Rays  

E-Print Network (OSTI)

ATLAS is one of the two general?purpose detectors at the Large Hadron Collider (LHC). The trigger system needs to efficiently reject a huge rate of background events and still select potentially interesting ones with good efficiency. After a first processing level using custom electronics, the trigger event selection is made by the High Level Trigger (HLT) system, implemented in software. To reduce the processing time to manageable levels, the HLT uses seeded, step?wise and fast selection algorithms, aiming at the earliest possible rejection of background events. The ATLAS trigger event selection is based on the reconstruction of potentially interesting physical objects like electrons, muons, jets etc. The recent LHC startup and short single?beam run provided the first test of the trigger system against real data. Following this period, ATLAS continued to collect cosmic?ray events for detector alignment and calibration purposes. Both running periods provided very important data to commission the trigg...

Urquijo, P; The ATLAS collaboration

2009-01-01T23:59:59.000Z

213

Kolmogorov-Smirnov test as a tool to study the distribution of ultra-high energy cosmic ray sources  

E-Print Network (OSTI)

We analyze in detail the two-dimensional Kolmogorov-Smirnov test as a tool to learn about the distribution of the sources of the ultra-high energy cosmic rays. We confront in particular models based on AGN observed in X rays, on galaxies observed in HI and isotropic distributions, discussing how this method can be used not only to reject isotropy but also to support or reject specific source models, extending results obtained recently in the literature.

Diego Harari; Silvia Mollerach; Esteban Roulet

2008-10-31T23:59:59.000Z

214

HIGH-ENERGY EMISSION INDUCED BY ULTRA-HIGH-ENERGY PHOTONS AS A PROBE OF ULTRA-HIGH-ENERGY COSMIC-RAY ACCELERATORS EMBEDDED IN THE COSMIC WEB  

SciTech Connect

The photomeson production in ultra-high-energy cosmic-ray (UHECR) accelerators such as {gamma}-ray bursts and active galaxies may lead to ultra-high-energy (UHE) {gamma}-ray emission. We show that the generation of UHE pairs in magnetized structured regions where the sources are embedded is inevitable, and accompanying {approx}> 0.1 TeV synchrotron emission provides an important probe of UHECR acceleration. It would especially be relevant for powerful transient sources, and synchrotron pair echoes may be detected by future CTA via coordinated search for transients of duration {approx}0.1-1 yr for the structured regions of {approx}Mpc. Detections will be useful for knowing structured extragalactic magnetic fields as well as properties of the sources.

Murase, Kohta [Department of Physics, Center for Cosmology and AstroParticle Physics, Ohio State University, Columbus, OH 43210 (United States)

2012-02-15T23:59:59.000Z

215

EVIDENCE FOR PARTICLE ACCELERATION TO THE KNEE OF THE COSMIC RAY SPECTRUM IN TYCHO'S SUPERNOVA REMNANT  

Science Conference Proceedings (OSTI)

Supernova remnants (SNRs) have long been assumed to be the source of cosmic rays (CRs) up to the 'knee' of the CR spectrum at 10{sup 15} eV, accelerating particles to relativistic energies in their blast waves by the process of diffusive shock acceleration (DSA). Since CR nuclei do not radiate efficiently, their presence must be inferred indirectly. Previous theoretical calculations and X-ray observations show that CR acceleration significantly modifies the structure of the SNR and greatly amplifies the interstellar magnetic field. We present new, deep X-ray observations of the remnant of Tycho's supernova (SN 1572, henceforth Tycho), which reveal a previously unknown, strikingly ordered pattern of non-thermal high-emissivity stripes in the projected interior of the remnant, with spacing that corresponds to the gyroradii of 10{sup 14}-10{sup 15} eV protons. Spectroscopy of the stripes shows the plasma to be highly turbulent on the (smaller) scale of the Larmor radii of TeV energy electrons. Models of the shock amplification of magnetic fields produce structure on the scale of the gyroradius of the highest energy CRs present, but they do not predict the highly ordered pattern we observe. We interpret the stripes as evidence for acceleration of particles to near the knee of the CR spectrum in regions of enhanced magnetic turbulence, while the observed highly ordered pattern of these features provides a new challenge to models of DSA.

Eriksen, Kristoffer A.; Hughes, John P. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States); Badenes, Carles [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Fesen, Robert [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Ghavamian, Parviz [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Moffett, David [Department of Physics, Furman University, Greenville, SC 29613 (United States); Plucinksy, Paul P.; Slane, Patrick [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Rakowski, Cara E. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Reynoso, Estela M. [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina)

2011-02-20T23:59:59.000Z

216

Shock Speed, Cosmic Ray Pressure, and Gas Temperature in the Cygnus Loop  

E-Print Network (OSTI)

Upper limits on the shock speeds in supernova remnants can be combined with post-shock temperatures to obtain upper limits on the ratio of cosmic ray to gas pressure (P_CR / P_G) behind the shocks. We constrain shock speeds from proper motions and distance estimates, and we derive temperatures from X-ray spectra. The shock waves are observed as faint H-alpha filaments stretching around the Cygnus Loop supernova remnant in two epochs of the Palomar Observatory Sky Survey (POSS) separated by 39.1 years. We measured proper motions of 18 non-radiative filaments and derived shock velocity limits based on a limit to the Cygnus Loop distance of 576 +/- 61 pc given by Blair et al. for a background star. The PSPC instrument on-board ROSAT observed the X-ray emission of the post-shock gas along the perimeter of the Cygnus Loop, and we measure post-shock electron temperature from spectral fits. Proper motions range from 2.7 arcseconds to 5.4 arcseconds over the POSS epochs and post-shock temperatures range from kT ~ 100...

Salvesen, Greg; Edgar, Richard J

2008-01-01T23:59:59.000Z

217

Passive Imaging of Warhead-Like Configurations Using Cosmic-Ray Muons  

SciTech Connect

Cosmic-Muon-Based Interrogation has untapped potential for national security. This presentation describes muons-based passive interrogation techniques.

Schwellenbach, D.

2012-07-17T23:59:59.000Z

218

INFLUENCE OF TURBULENCE DISSIPATION EFFECTS ON THE PROPAGATION OF LOW-ENERGY COSMIC RAYS IN THE GALAXY  

Science Conference Proceedings (OSTI)

The propagation of cosmic rays in the Galaxy is controlled by spatial diffusion coefficients. Since parallel scattering is the strongest scattering effect, it is believed that the diffusion coefficient along the mean magnetic field controls the confinement of charged cosmic particles in the Galaxy. In this paper, we combine a turbulence spectrum with dissipation range with a nonlinear particle diffusion theory to compute transport parameters. We find a decreasing parallel diffusion coefficient for increasing particle energy for particles having rigidities lower than 3 GeV. Our approach provides an explanation of the observed boron-to-carbon ratio at these particle energies without the need to introduce stochastic acceleration.

Shalchi, A. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Buesching, I., E-mail: andreasm4@yahoo.co [Institut fuer Theoretische Physik, Lehrstuhl IV, Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2010-12-20T23:59:59.000Z

219

The Cosmic Ray Precursor of Relativistic Collisionless Shocks: A Missing Link in Gamma-Ray Burst Afterglows  

E-Print Network (OSTI)

Collisionless shocks are commonly argued to be the sites of cosmic ray (CR) acceleration. We study the influence of CRs on weakly magnetized relativistic collisionless shocks and apply our results to external shocks in gamma-ray burst (GRB) afterglows. The common view is that the transverse Weibel instability (TWI) generates a small-scale magnetic field which facilitates collisional coupling and thermalization in the shock transition. The TWI field is expected to decay rapidly, over a finite number of proton plasma skin depths from the transition. However, the synchrotron emission in GRB afterglows suggests that a strong and persistent magnetic field is present in the plasma that crosses the shock; the origin of this field is a key open question. Here we find that the common picture involving TWI demands revision. Namely, the CRs drive turbulence in the shock upstream on scales much larger than the skin depth. This turbulence generates a large-scale magnetic field that quenches TWI and produces a magnetized s...

Milosavljevic, M; Milosavljevic, Milos; Nakar, Ehud

2005-01-01T23:59:59.000Z

220

HOW MANY ULTRA-HIGH ENERGY COSMIC RAYS COULD WE EXPECT FROM CENTAURUS A?  

Science Conference Proceedings (OSTI)

The Pierre Auger Observatory has associated a few ultra-high energy cosmic rays (UHECRs) with the direction of Centaurus A. This source has been deeply studied in radio, infrared, X-ray, and {gamma}-rays (MeV-TeV) because it is the nearest radio-loud active galactic nucleus. Its spectral energy distribution or spectrum shows two main peaks, the low-energy peak, at an energy of 10{sup -2} eV, and the high-energy peak, at about 150 keV. There is also a faint very high energy (VHE; E {>=} 100 GeV) {gamma}-ray emission fully detected by the High Energy Stereoscopic System experiment. In this work, we describe the entire spectrum: the two main peaks with a synchrotron/synchrotron self-Compton model, and the VHE emission with a hadronic model. We consider p{gamma} and pp interactions. For the p{gamma} interaction, we assume that the target photons are those produced at 150 keV in leptonic processes. On the other hand, for the pp interaction we consider as targets the thermal particle densities in the lobes. Requiring a satisfactory description of the spectra at very high energies with p{gamma} interaction, we obtain an excessive luminosity in UHECRs (even exceeding the Eddington luminosity). However, when considering the pp interaction to describe the {gamma}-spectrum, the number of UHECRs obtained is in agreement with Pierre Auger observations. We also calculate the possible neutrino signal from pp interactions on a Km{sup 3} neutrino telescope using Monte Carlo simulations.

Fraija, N.; Gonzalez, M. M.; Perez, M. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Circuito Exterior, C.U., A. Postal 70-264, 04510 Mexico D.F. (Mexico); Marinelli, A., E-mail: nifraija@astro.unam.mx, E-mail: magda@astro.unam.mx, E-mail: jguillen@astro.unam.mx, E-mail: antonio.marinelli@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, C.U., A. Postal 70-264, 04510 Mexico D.F. (Mexico)

2012-07-01T23:59:59.000Z

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221

Estimating a cosmic ray detector exposure sky map under the hypothesis of seasonal and diurnal effects factorization  

E-Print Network (OSTI)

The measurement of large scale patterns or anisotropies in the arrival direction of high energy cosmic rays is an important step towards the understanding of their origin. Such measurements rely on an accurate estimation of the detector relative exposure in each direction on the sky : the coverage map. To reach an accuracy on the determination of this map below the one percent level one must properly identify and correct for all the environmental effects that may induce variations in the detector exposure as a function of time. In an approach, similar to the one used in anti-sidereal time analysis, we propose a method to empirically estimate and correct for those effects under the hypothesis that seasonal and diurnal variations can be factorized. We tested this method using a model ground detector of cosmic ray air showers, whose aperture varies due to the dependence of the air shower development on the atmospheric conditions.

E. M. Santos; C. Bonifazi; A. Letessier-Selvon

2008-04-09T23:59:59.000Z

222

Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon  

Science Conference Proceedings (OSTI)

The shadowing of cosmic ray primaries by the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 {sigma} level and the shadow of the sun at the 3.8 {sigma} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 {+-} 0.12{sup o}. Hints of interplanetary magnetic field effects were observed in both the sun and moon shadow.

Jaffe, D.E.; Bishai, M.; Diwan, M.V.; Ling, J.; Viren, B.; Whitehead, L.,.

2010-10-10T23:59:59.000Z

223

Probing the ATIC peak in the cosmic-ray electron spectrum with H.E.S.S  

E-Print Network (OSTI)

The measurement of an excess in the cosmic-ray electron spectrum between 300 and 800 GeV by the ATIC experiment has - together with the PAMELA detection of a rise in the positron fraction up to 100 GeV - motivated many interpretations in terms of dark matter scenarios; alternative explanations assume a nearby electron source like a pulsar or supernova remnant. Here we present a measurement of the cosmic-ray electron spectrum with H.E.S.S. starting at 340 GeV. The H.E.S.S. data with their lower statistical errors show no indication of a structure in the electron spectrum, but rather a power-law spectrum with spectral index of 3.0 +- 0.1 (stat.) +- 0.3 (syst.) which steepens at about 1 TeV.

Aharonian, F

2009-01-01T23:59:59.000Z

224

Perturbations to aquatic photosynthesis due to high-energy cosmic ray induced muon flux in the extragalactic shock model  

E-Print Network (OSTI)

We modify a mathematical model of photosynthesis to quantify the perturbations that high energy muons could make on aquatic primary productivity. Then we apply this in the context of the extragalactic shock model, according to which Earth receives an enhanced dose of high-energy cosmic rays when it is at the galactic north. We obtain considerable reduction in the photosynthesis rates, consistent with potential drops in biodiversity.

Rodriguez, Lien; Rodriguez, Oscar

2013-01-01T23:59:59.000Z

225

ASSESSING THE FEASIBILITY OF COSMIC-RAY ACCELERATION BY MAGNETIC TURBULENCE AT THE GALACTIC CENTER  

SciTech Connect

The presence of relativistic particles at the center of our Galaxy is evidenced by the diffuse TeV emission detected from the inner {approx}2 Degree-Sign of the Galaxy. Although it is not yet entirely clear whether the origin of the TeV photons is due to hadronic or leptonic interactions, the tight correlation of the intensity distribution with the distribution of molecular gas along the Galactic ridge strongly points to a pionic-decay process involving relativistic protons. In previous work, we concluded that point-source candidates, such as the supermassive black hole Sagittarius A* (identified with the High-Energy Stereoscopic System (HESS) source J1745-290) or the pulsar wind nebulae dispersed along the Galactic plane, could not account for the observed diffuse TeV emission from this region. Motivated by this result, we consider here the feasibility that the cosmic rays populating the Galactic center region are accelerated in situ by magnetic turbulence. Our results indicate that even in a highly conductive environment, this mechanism is efficient enough to energize protons within the intercloud medium to the {approx}>TeV energies required to produce the HESS emission.

Fatuzzo, M. [Physics Deparment, Xavier University, Cincinnati, OH 45207 (United States); Melia, F., E-mail: fatuzzo@xavier.edu, E-mail: fmelia@email.arizona.edu [Department of Physics, Applied Math Program, and Steward Observatory, University of Arizona, AZ 85721 (United States)

2012-05-01T23:59:59.000Z

226

Multiple Production, Transport in Atmosphere and Detection of High Energy Cosmic Rays  

E-Print Network (OSTI)

We describe the general aspects of Monte Carlo Collision Generators suitable for cosmic ray nucleon-Air and nuclei-Air interactions, including accelerator and collider data. The problem of the extrapolation at 3 energy decades above the LHC of the main features of high energy collisions is discussed and under theoretical and phenomenological assumptions, the properties of the longitudinal and lateral development of giant extensive air showers simulated with the CORSIKA program are presented. The determination of the primary energy near $10^{20}$ eV is examined for different observables, total size, densities of charged particles interpolated at 600~m from shower core. The extensive air shower data collected around LHC energy is in better agreement with models of large multiplicities. Beyond this energy, the extrapolation carried assuming the diquark breaking mechanism can change the classic conversion to primary energy and such circumstance can have consequences on the validity of the GZK cut off. In those conditions, we have simulated large and giant air showers taking into account, in addition, new processes, such as diquark breaking, and topological problems involving adequate structure functions for lateral distributions, up to energies exceeding $10^{20}$ eV for P.AUGER and EUSO experiments.

Jean-No{ë}l Capdevielle; Fabrice Cohen; Corentin Le Gall

2001-11-30T23:59:59.000Z

227

Radius of influence for a cosmic-ray soil moisture probe : theory and Monte Carlo simulations.  

Science Conference Proceedings (OSTI)

The lateral footprint of a cosmic-ray soil moisture probe was determined using diffusion theory and neutron transport simulations. The footprint is radial and can be described by a single parameter, an e-folding length that is closely related to the slowing down length in air. In our work the slowing down length is defined as the crow-flight distance traveled by a neutron from nuclear emission as a fast neutron to detection at a lower energy threshold defined by the detector. Here the footprint is defined as the area encompassed by two e-fold distances, i.e. the area from which 86% of the recorded neutrons originate. The slowing down length is approximately 150 m at sea level for neutrons detected over a wide range of energies - from 10{sup 0} to 10{sup 5} eV. Both theory and simulations indicate that the slowing down length is inversely proportional to air density and linearly proportional to the height of the sensor above the ground for heights up to 100 m. Simulations suggest that the radius of influence for neutrons >1 eV is only slightly influenced by soil moisture content, and depends weakly on the energy sensitivity of the neutron detector. Good agreement between the theoretical slowing down length in air and the simulated slowing down length near the air/ground interface support the conclusion that the footprint is determined mainly by the neutron scattering properties of air.

Desilets, Darin

2011-02-01T23:59:59.000Z

228

Measurements of the Cosmic-Ray Positron Fraction From 1 to 50 GeV  

E-Print Network (OSTI)

Two measurements of the cosmic-ray positron fraction as a function of energy have been made using the High Energy Antimatter Telescope (HEAT) balloon-borne instrument. The first flight took place from Ft. Sumner, New Mexico in 1994, and yielded results above the geomagnetic cutoff energy of 4.5 GeV. The second flight from Lynn Lake, Manitoba in 1995 permitted measurements over a larger energy interval, from 1 GeV to 50 GeV. In this letter we present results on the positron fraction based on data from the Lynn Lake flight, and compare these with the previously published results from the Ft. Sumner flight. The results confirm that the positron fraction does not increase with energy above ~10 GeV, although a small excess above purely secondary production cannot be ruled out. At low energies the positron fraction is slightly larger than that reported from measurements made in the 1960's. This effect could possibly be a consequence of charge dependence in the level of solar modulation.

HEAT Collaboration; S. W. Barwick; E. Schneider; J. J. Beatty; G. A. de Nolfo; A. Bhattacharyya; C. R. Bower; J. A. Musser; C. J. Chaput; S. Coutu; S. McKee; G. Tarle; A. D. Tomasch; J. Knapp; D. M. Lowder; D. Muller; S. P. Swordy; E. Torbet; S. L. Nutter

1997-03-28T23:59:59.000Z

229

Measurement of the Cosmic Ray and Neutrino-Induced Muon Flux at the Sudbury Neutrino Observatory  

SciTech Connect

Results are reported on the measurement of the atmospheric neutrino-induced muon flux at a depth of 2 kilometers below the Earth's surface from 1229 days of operation of the Sudbury Neutrino Observatory (SNO). By measuring the flux of through-going muons as a function of zenith angle, the SNO experiment can distinguish between the oscillated and un-oscillated portion of the neutrino flux. A total of 514 muon-like events are measured between -1 {le} cos {theta}{sub zenith} 0.4 in a total exposure of 2.30 x 10{sup 14} cm{sup 2} s. The measured flux normalization is 1.22 {+-} 0.09 times the Bartol three-dimensional flux prediction. This is the first measurement of the neutrino-induced flux where neutrino oscillations are minimized. The zenith distribution is consistent with previously measured atmospheric neutrino oscillation parameters. The cosmic ray muon flux at SNO with zenith angle cos {theta}{sub zenith} > 0.4 is measured to be (3.31 {+-} 0.01 (stat.) {+-} 0.09 (sys.)) x 10{sup -10} {micro}/s/cm{sup 2}.

SNO collaboration; Aharmim, B.; Ahmed, S.N.; Andersen, T.C.; Anthony, A.E.; Barros, N.; Beier, E.W.; Bellerive, A.; Beltran, B.; Bergevin, M.; Biller, S.D.; Boudjemline, K.; Boulay, M.G.; Burritt, T.H.; Cai, B.; Chan, Y.D.; Chen, M.; Chon, M.C.; Cleveland, B.T.; Cox-Mobrand, G.A.; Currat, C.A.; Dai, X.; Dalnoki-Veress, F.; Deng, H.; Detwiler, J.; Doe, P.J.; Dosanjh, R.S.; Doucas, G.; Drouin, P.-L.; Duncan, F.A.; Dunford, M.; Elliott, S.R.; Evans, H.C.; Ewan, G.T.; Farine, J.; Fergani, H.; Fleurot, F.; Ford, R.J.; Formaggio, J.A.; Gagnon, N.; Goon, J.TM.; Grant, D.R.; Guillian, E.; Habib, S.; Hahn, R.L.; Hallin, A.L.; Hallman, E.D.; Hargrove, C.K.; Harvey, P.J.; Harvey, P.J.; Heeger, K.M.; Heintzelman, W.J.; Heise, J.; Helmer, R.L.; Hemingway, R.J.; Henning, R.; Hime, A.; Howard, C.; Howe, M.A.; Huang, M.; Jamieson, B.; Jelley, N.A.; Klein, J.R.; Kos, M.; Kruger, A.; Kraus, C.; Krauss, C.B.; Kutter, T.; Kyba, C.C.M.; Lange, R.; Law, J.; Lawson, I.T.; Lesko, K.T.; Leslie, J.R.; Levine, I.; Loach, J.C.; Luoma, S.; MacLellan, R.; Majerus, S.; Mak, H.B.; Maneira, J.; Marino, A.D.; Martin, R.; McCauley, N.; McDonald, A.B.; McGee, S.; Mifflin, C.; Miller, M.L.; Monreal, B.; Monroe, J.; Noble, A.J.; Oblath, N.S.; Okada, C.E.; O?Keeffe, H.M.; Opachich, Y.; Orebi Gann, G.D.; Oser, S.M.; Ott, R.A.; Peeters, S.J.M.; Poon, A.W.P.; Prior, G.; Rielage, K.; Robertson, B.C.; Robertson, R.G.H.; Rollin, E.; Schwendener, M.H.; Secrest, J.A.; Seibert, S.R.; Simard, O.; Simpson, J.J.; Sinclair, D.; Skensved, P.; Smith, M.W.E.; Sonley, T.J.; Steiger, T.D.; Stonehill, L.C.; Tagg, N.; Tesic, G.; Tolich, N.; Tsui, T.; Van de Water, R.G.; VanDevender, B.A.; Virtue, C.J.; Waller, D.; Waltham, C.E.; Wan Chan Tseung, H.; Wark, D.L.; Watson, P.; Wendland, J.; West, N.; Wilkerson, J.F.; Wilson, J.R.; Wouters, J.M.; Wright, A.; Yeh, M.; Zhang, F.; Zuber, K.

2009-02-16T23:59:59.000Z

230

DESPIKING OF SPACECRAFT ENERGETIC PROTON FLUX TO STUDY GALACTIC COSMIC-RAY MODULATION  

Science Conference Proceedings (OSTI)

Galactic cosmic ray (GCR) is usually assumed as a stable 'background', with solar influence considered as a modulation. The violent solar energetic particle (SEP) events associated with solar activities change particle fluxes by several orders of magnitude in a few minutes. Thus, the flux observation of GCR provided by satellites may be heavily contaminated by spurious spikes due to SEPs, and that provided by ground-based neutron monitors (NMs) may be contaminated by the system error spikes and the ground level enhancement effect. To obtain the 'pure' background GCR flux for modulation research, the removal of multifarious spikes is necessary. In this article, we use a robust automatic despiking algorithm based on the Poincare map thresholding method provided by Goring and Nikora for 'purification' of the time-series GCR flux observations. We can show that the algorithm is good at cleaning up the heavily contaminated GCR intensity rates measured by both spacecraft and NMs without artificial parameters. In addition, using the algorithm to despike the spacecraft observations of relatively lower energetic proton flux, we get both 11 year and 27 day period cycles comparable to the much higher energy GCR flux data measured by the ground-based NMs.

Qin, G.; Zhao, L.-L. [State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Chen, H.-C., E-mail: gqin@spaceweather.ac.cn, E-mail: llzhao@spaceweather.ac.cn, E-mail: chchao@mail.ustc.edu.cn [Laboratory of Geophysical experiment, Institute of Geophysics, China Earthquake Administration, Beijing 100081 (China)

2012-06-20T23:59:59.000Z

231

The initial conditions of star formation: cosmic rays as the fundamental regulators  

E-Print Network (OSTI)

Cosmic rays (CRs) control the thermal, ionization and chemical state of the dense H_2 gas regions that otherwise remain shielded from far-UV and optical stellar radiation propagating through the dusty ISM of galaxies. It is in such CR-dominated regions (CRDRs) rather than Photon-dominated regions (PDRs) of H_2 clouds where the star formation initial conditions are set, making CRs the ultimate star-formation feedback factor in galaxies, able to operate even in their most deeply dust-enshrouded environments. CR-controlled star formation initial conditions naturally set the stage for a near-invariant stellar Initial Mass Function (IMF) in galaxies as long as their average CR energy density U_{CR} permeating their molecular ISM remains within a factor of ~10 of its Galactic value. Nevertheless, in the extreme environments of the compact starbursts found in merging galaxies, where U_{CR}\\sim(few)x10^{3}U_{CR,Gal}, CRs dramatically alter the initial conditions of star formation. In the resulting extreme CRDRs H_2 c...

Papadopoulos, Padelis P

2012-01-01T23:59:59.000Z

232

Cosmic ray velocity and electric charge measurements with the AMS/RICH detector: prototype results  

E-Print Network (OSTI)

The Alpha Magnetic Spectrometer (AMS) to be installed on the International Space Station (ISS) will measure charged cosmic ray spectra of elements up to iron, in the rigidity range from 1 GV to 1 TV, for at least three years. AMS is a large angular spectrometer composed of different subdetectors, including a proximity focusing Ring Imaging CHerenkov (RICH) detector. This will be equipped with a mixed radiator made of aerogel and sodium fluoride (NaF), a lateral conical mirror and a detection plane made of 680 photomultipliers coupled to light guides. The RICH detector allows measurements of particle's electric charge up to iron, and particle's velocity. Two possible methods for reconstructing the Cherenkov angle and the electric charge with the RICH will be discussed. A RICH prototype consisting of a detection matrix with 96 photomultipliers, a segment of a conical mirror and samples of the radiator materials was built and its performance was evaluated using ion beam data. Results from the last test beam performed with ion fragments resulting from the collision of a 158 GeV/c/nucleon primary beam of indium ions (CERN SPS) on a lead target are reported. The large amount of collected data allowed to test and characterize different aerogel samples and the NaF radiator. In addition, the reflectivity of the mirror was evaluated. The data analysis confirms the design goals.

Luísa Arruda; Fernando Barão; Patrícia Gonçalves; Rui Pereira

2008-01-31T23:59:59.000Z

233

Towards unravelling the structural distribution of ultra-high-energy cosmic ray sources  

E-Print Network (OSTI)

We investigate the possibility that near future observations of ultra-high-energy cosmic rays (UHECRs) can unveil their local source distribution, which reflects the observed local structures if their origins are astrophysical objects. In order to discuss this possibility, we calculate the arrival distribution of UHE protons taking into account their propagation process in intergalactic space i.e. energy losses and deflections by extragalactic magnetic field (EGMF). For a realistic simulation, we construct and adopt a model of a structured EGMF and UHECR source distribution, which reproduce the local structures actually observed around the Milky Way. The arrival distribution is compared statistically to their source distribution using correlation coefficient. We specially find that UHECRs above $10^{19.8}$eV are best indicators to decipher their source distribution within 100 Mpc, and detection of about 500 events on all the sky allows us to unveil the local structure of UHE universe for plausible EGMF strength and the source number density. This number of events can be detected by five years observation by Pierre Auger Observatory.

Hajime Takami; Katsuhiko Sato

2007-10-03T23:59:59.000Z

234

Measurement of Cosmic Ray Spectrum and Anisotropy with the ARGO-YBJ experiment  

E-Print Network (OSTI)

The combined measurement of the cosmic ray (CR) energy spectrum and anisotropy in their arrival direction distribution needs the knowledge of the elemental composition of the radiation to discriminate between different origin and propagation models. Important information on the CR mass composition can be obtained studying the EAS muon content through the measurement of the CR rate at different zenith angles. In this paper we report on the observation of the anisotropy of galactic CRs at different angular scales with the ARGO-YBJ experiment. We report also on the study of the primary CR rate for different zenith angles. The light component (p+He) has been selected and its energy spectrum measured in the energy range (5 - 200) TeV for quasi-vertical events. With this analysis for the first time a ground-based measurement of the CR spectrum overlaps data obtained with direct methods for more than one energy decade, thus providing a solid anchorage to the CR spectrum measurements carried out by EAS arrays in the ...

Di Sciascio, G

2013-01-01T23:59:59.000Z

235

Measurements of the Cosmic-Ray Positron Fraction From 1 to 50 GeV  

E-Print Network (OSTI)

Two measurements of the cosmic-ray positron fraction as a function of energy have been made using the High Energy Antimatter Telescope (HEAT) balloon-borne instrument. The first flight took place from Ft. Sumner, New Mexico in 1994, and yielded results above the geomagnetic cutoff energy of 4.5 GeV. The second flight from Lynn Lake, Manitoba in 1995 permitted measurements over a larger energy interval, from 1 GeV to 50 GeV. In this letter we present results on the positron fraction based on data from the Lynn Lake flight, and compare these with the previously published results from the Ft. Sumner flight. The results confirm that the positron fraction does not increase with energy above ~10 GeV, although a small excess above purely secondary production cannot be ruled out. At low energies the positron fraction is slightly larger than that reported from measurements made in the 1960's. This effect could possibly be a consequence of charge dependence in the level of solar modulation.

Barwick, S W; Beatty, J J; De Nolfo, G A; Bhattacharya, A; Bower, C; Musser, J A; Chaput, C J; Coutu, S; McKee, S; Tarlé, G; Tomasch, A D; Knapp, J; Lowder, D M; Müller, D; Swordy, S P; Torbet, E; Nutter, S L

1997-01-01T23:59:59.000Z

236

THE COSMIC-RAY ENERGY SPECTRUM OBSERVED WITH THE SURFACE DETECTOR OF THE TELESCOPE ARRAY EXPERIMENT  

SciTech Connect

The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays (UHECRs) with primary energies above 1.6 Multiplication-Sign 10{sup 18} eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 Multiplication-Sign 10{sup 18} eV and a steepening at 5.4 Multiplication-Sign 10{sup 19} eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of UHECR surface detector data, that involves generating a complete simulation of UHECRs striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the ''thinning'' approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned.

Abu-Zayyad, T.; Allen, M.; Anderson, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Hanlon, W. [High Energy Astrophysics Institute and Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah (United States); Aida, R. [University of Yamanashi, Interdisciplinary Graduate School of Medicine and Engineering, Kofu, Yamanashi (Japan); Azuma, R.; Fukuda, T. [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Cheon, B. G.; Cho, E. J. [Department of Physics and Research Institute of Natural Science, Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Chiba, J. [Department of Physics, Tokyo University of Science, Noda, Chiba (Japan); Chikawa, M. [Department of Physics, Kinki University, Higashi Osaka, Osaka (Japan); Cho, W. R. [Department of Physics, Yonsei University, Seodaemun-gu, Seoul (Korea, Republic of); Fujii, H. [Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki (Japan); Fujii, T. [Graduate School of Science, Osaka City University, Osaka, Osaka (Japan); Fukushima, M. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba (Japan); and others

2013-05-01T23:59:59.000Z

237

Hadronic forward scattering: Predictions for the Large Hadron Collider and cosmic rays  

E-Print Network (OSTI)

The status of hadron-hadron interactions is reviewed, with emphasis on the forward and near-forward scattering regions. From analyticity, Finite Energy Sum Rules are introduced from which new analyticity constraints are derived that exploit the many very accurate low energy experimental cross sections, i.e., they constrain the values of the asymptotic cross sections and their derivatives at low energies just above the resonance regions, allowing us new insights into duality. A new robust fitting technique is introduced in order to `clean up' large data samples that are contaminated by outliers. Using our analyticity constraints, new methods of fitting high energy hadronic data are introduced which result in much more precise estimates of the fit parameters, allowing accurate extrapolations to much higher energies. It's shown that the $\\gamma p$, $\\pi^\\pm p$ and nucleon-nucleon cross sections {\\em all} go asymptotically as $\\ln^2s$, saturating the Froissart bound, while conclusively ruling out $\\ln s$ and $s^{\\alpha}$ ($\\alpha\\sim 0.08$) behavior. Implications of this saturation for predictions of $\\sigma_{pp}$ and $\\rho_{pp}$ at the LHC and for cosmic rays p-air cross sections are given.

Martin M. Block

2006-06-20T23:59:59.000Z

238

Measurement of the Cosmic Ray and Neutrino-Induced Muon Flux at the Sudbury Neutrino Observatory  

SciTech Connect

Results are reported on the measurement of the atmospheric neutrino-induced muon flux at a depth of 2 kilometers below the Earth's surface from 1229 days of operation of the Sudbury Neutrino Observatory (SNO). By measuring the flux of through-going muons as a function of zenith angle, the SNO experiment can distinguish between the oscillated and un-oscillated portion of the neutrino flux. A total of 514 muon-like events are measured between -1 {le} cos {theta}{sub zenith} 0.4 in a total exposure of 2.30 x 10{sup 14} cm{sup 2} s. The measured flux normalization is 1.22 {+-} 0.09 times the Bartol three-dimensional flux prediction. This is the first measurement of the neutrino-induced flux where neutrino oscillations are minimized. The zenith distribution is consistent with previously measured atmospheric neutrino oscillation parameters. The cosmic ray muon flux at SNO with zenith angle cos {theta}{sub zenith} > 0.4 is measured to be (3.31 {+-} 0.01 (stat.) {+-} 0.09 (sys.)) x 10{sup -10} {micro}/s/cm{sup 2}.

SNO collaboration; Aharmim, B.; Ahmed, S.N.; Andersen, T.C.; Anthony, A.E.; Barros, N.; Beier, E.W.; Bellerive, A.; Beltran, B.; Bergevin, M.; Biller, S.D.; Boudjemline, K.; Boulay, M.G.; Burritt, T.H.; Cai, B.; Chan, Y.D.; Chen, M.; Chon, M.C.; Cleveland, B.T.; Cox-Mobrand, G.A.; Currat, C.A.; Dai, X.; Dalnoki-Veress, F.; Deng, H.; Detwiler, J.; Doe, P.J.; Dosanjh, R.S.; Doucas, G.; Drouin, P.-L.; Duncan, F.A.; Dunford, M.; Elliott, S.R.; Evans, H.C.; Ewan, G.T.; Farine, J.; Fergani, H.; Fleurot, F.; Ford, R.J.; Formaggio, J.A.; Gagnon, N.; Goon, J.TM.; Grant, D.R.; Guillian, E.; Habib, S.; Hahn, R.L.; Hallin, A.L.; Hallman, E.D.; Hargrove, C.K.; Harvey, P.J.; Harvey, P.J.; Heeger, K.M.; Heintzelman, W.J.; Heise, J.; Helmer, R.L.; Hemingway, R.J.; Henning, R.; Hime, A.; Howard, C.; Howe, M.A.; Huang, M.; Jamieson, B.; Jelley, N.A.; Klein, J.R.; Kos, M.; Kruger, A.; Kraus, C.; Krauss, C.B.; Kutter, T.; Kyba, C.C.M.; Lange, R.; Law, J.; Lawson, I.T.; Lesko, K.T.; Leslie, J.R.; Levine, I.; Loach, J.C.; Luoma, S.; MacLellan, R.; Majerus, S.; Mak, H.B.; Maneira, J.; Marino, A.D.; Martin, R.; McCauley, N.; McDonald, A.B.; McGee, S.; Mifflin, C.; Miller, M.L.; Monreal, B.; Monroe, J.; Noble, A.J.; Oblath, N.S.; Okada, C.E.; O?Keeffe, H.M.; Opachich, Y.; Orebi Gann, G.D.; Oser, S.M.; Ott, R.A.; Peeters, S.J.M.; Poon, A.W.P.; Prior, G.; Rielage, K.; Robertson, B.C.; Robertson, R.G.H.; Rollin, E.; Schwendener, M.H.; Secrest, J.A.; Seibert, S.R.; Simard, O.; Simpson, J.J.; Sinclair, D.; Skensved, P.; Smith, M.W.E.; Sonley, T.J.; Steiger, T.D.; Stonehill, L.C.; Tagg, N.; Tesic, G.; Tolich, N.; Tsui, T.; Van de Water, R.G.; VanDevender, B.A.; Virtue, C.J.; Waller, D.; Waltham, C.E.; Wan Chan Tseung, H.; Wark, D.L.; Watson, P.; Wendland, J.; West, N.; Wilkerson, J.F.; Wilson, J.R.; Wouters, J.M.; Wright, A.; Yeh, M.; Zhang, F.; Zuber, K.

2009-02-16T23:59:59.000Z

239

EFFECTS OF NEUTRAL HYDROGEN ON COSMIC-RAY PRECURSORS IN SUPERNOVA REMNANT SHOCK WAVES  

Science Conference Proceedings (OSTI)

Many fast supernova remnant shocks show spectra dominated by Balmer lines. The H{alpha} profiles have a narrow component explained by direct excitations and a thermally Doppler broadened component due to atoms that undergo charge exchange in the post-shock region. However, the standard model does not take into account the cosmic-ray shock precursor, which compresses and accelerates plasma ahead of the shock. In strong precursors with sufficiently high densities, the processes of charge exchange, excitation, and ionization will affect the widths of both narrow and broad line components. Moreover, the difference in velocity between the neutrals and the precursor plasma gives rise to frictional heating due to charge exchange and ionization in the precursor. In extreme cases, all neutrals can be ionized by the precursor. In this Letter we compute the ion and electron heating for a wide range of shock parameters, along with the velocity distribution of the neutrals that reach the shock. Our calculations predict very large narrow component widths for some shocks with efficient acceleration, along with changes in the broad-to-narrow intensity ratio used as a diagnostic for the electron-ion temperature ratio. Balmer lines may therefore provide a unique diagnostic of precursor properties. We show that heating by neutrals in the precursor can account for the observed H{alpha} narrow component widths and that the acceleration efficiency is modest in most Balmer line shocks observed thus far.

Raymond, John C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Vink, J.; Helder, E. A.; De Laat, A., E-mail: jraymond@cfa.harvard.edu [Astronomical Institute, Utrecht University, P.O. Box 80000, 3508TA Utrecht (Netherlands)

2011-04-10T23:59:59.000Z

240

Radio detection of high-energy cosmic rays at the Pierre Auger Observatory  

E-Print Network (OSTI)

The southern Auger Observatory provides an excellent test bed to study the radio detection of extensive air showers as an alternative, cost-effective, and accurate tool for cosmic-ray physics. The data from the radio setup can be correlated with those from the well-calibrated baseline detectors of the Pierre Auger Observatory. Furthermore, human-induced radio noise levels at the southern Auger site are relatively low. We have started an R&D program to test various radio-detection concepts. Our studies will reveal Radio Frequency Interferences (RFI) caused by natural effects such as day-night variations, thunderstorms, and by human-made disturbances. These RFI studies are conducted to optimise detection parameters such as antenna design, frequency interval, antenna spacing and signal processing. The data from our initial setups, which presently consist of typically 3 - 4 antennas, will be used to characterise the shower from radio signals and to optimise the initial concepts. Furthermore, the operation of a large detection array requires autonomous detector stations. The current design is aiming at stations with antennas for two polarisations, solar power, wireless communication, and local trigger logic. The results of this initial phase will provide an important stepping stone for the design of a few tens kilometers square engineering array

A. M. van den Berg; for the Pierre Auger Collaboration

2007-08-13T23:59:59.000Z

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241

The Cosmic-Ray antiproton flux between 3 and 49 GeV  

E-Print Network (OSTI)

We report on a new measurement of the cosmic ray antiproton spectrum. The data were collected by the balloon-borne experiment CAPRICE98 which was flown on 28-29 May 1998 from Fort Sumner, New Mexico, USA. The experiment used the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas Ring Imaging Cherenkov (RICH) detector, a time-of-flight system, a tracking device consisting of drift chambers and a superconducting magnet and a silicon-tungsten calorimeter. The RICH detector was the first ever flown capable of mass-resolving charge-one particles at energies above 5 GeV. A total of 31 antiprotons with rigidities between 4 and 50 GV at the spectrometer were identified with small backgrounds from other particles. The absolute antiproton energy spectrum was determined in the kinetic energy region at the top of the atmosphere between 3.2 and 49.1 GeV. We found that the observed antiproton spectrum and the antiproton-to-proton ratio are consistent with a pure secondary origin. However, a primary component may not be excluded.

WiZard/CAPRICE Collaboration

2001-03-30T23:59:59.000Z

242

Towards a Solution to the Early Faint Sun Paradox: A Lower Cosmic Ray Flux from a Stronger Solar Wind  

E-Print Network (OSTI)

Standard solar models predict a solar luminosity that gradually increased by about 30% over the past 4.5 billion years. Under the faint sun, Earth should have been frozen solid for most of its existence. Yet, running water is observed to have been present since very early in Earth's history. This enigma is known as the faint sun paradox. We show here that it can be partially resolved once we consider the cooling effect that cosmic rays are suspected to have on the global climate and that the younger sun must have had a stronger solar wind, such that it was more effective at stopping cosmic rays from reaching Earth. The paradox can then be completely resolved with the further contribution of modest greenhouse gas warming. When we add the cosmic ray flux modulation by a variable star formation rate in the Milky Way, we recover the long term glacial activity on Earth. As to the future, we find that the average global temperature will increase by typically 10K in the coming 2 Gyr.

Nir J. Shaviv

2003-06-23T23:59:59.000Z

243

Dark Matter May be Strongly Visible in UHE Cosmic Rays and Related New Physics May be Appearing at the LHC  

E-Print Network (OSTI)

A two flavor color sextet quark sector added to QCD yields the {\\it uniquely} unitary Critical Pomeron at high energy while also producing electroweak symmetry breaking. In this paper it is argued that a number of experimental phenomena in Cosmic Ray and hadron collider physics can be interpreted as evidence for the sextet sector, as follows. 1. The majority of UHE cosmic rays are Dark Matter sextet neutrons. 2. The cosmic ray spectrum knee is a production threshold for sextet states. 3. The enhancement of high multiplicities and small pT at the LHC is related to a sextet generated triple pomeron coupling. 4. Tevatron and LHC events containing a Z pair and a high multiplicity of small pT particles are associated with sextet electroweak symmetry breaking. 5. Top quark production is via the $\\eta_6$ sextet quark pseudoscalar resonance - interference with the background will produce an asymmetry. 6. Enhanced W pair production would produce an excess in the W + dijet cross-section. Combining the sextet sector and...

White, Alan R

2011-01-01T23:59:59.000Z

244

MEASUREMENTS OF THE RELATIVE ABUNDANCES OF HIGH-ENERGY COSMIC-RAY NUCLEI IN THE TeV/NUCLEON REGION  

SciTech Connect

We present measurements of the relative abundances of cosmic-ray nuclei in the energy range of 500-3980 GeV/nucleon from the second flight of the Cosmic Ray Energetics And Mass balloon-borne experiment. Particle energy was determined using a sampling tungsten/scintillating-fiber calorimeter, while particle charge was identified precisely with a dual-layer silicon charge detector installed for this flight. The resulting element ratios C/O, N/O, Ne/O, Mg/O, Si/O, and Fe/O at the top of atmosphere are 0.919 {+-} 0.123{sup stat} {+-} 0.030{sup syst}, 0.076 {+-} 0.019{sup stat} {+-} 0.013{sup syst}, 0.115 {+-} 0.031{sup stat} {+-} 0.004{sup syst}, 0.153 {+-} 0.039{sup stat} {+-} 0.005{sup syst}, 0.180 {+-} 0.045{sup stat} {+-} 0.006{sup syst}, and 0.139 {+-} 0.043{sup stat} {+-} 0.005{sup syst}, respectively, which agree with measurements at lower energies. The source abundance of N/O is found to be 0.054 {+-} 0.013{sup stat} {+-} 0.009{sup syst+0.010esc} {sub -0.017}. The cosmic-ray source abundances are compared to local Galactic (LG) abundances as a function of first ionization potential and as a function of condensation temperature. At high energies the trend that the cosmic-ray source abundances at large ionization potential or low condensation temperature are suppressed compared to their LG abundances continues. Therefore, the injection mechanism must be the same at TeV/nucleon energies as at the lower energies measured by HEAO-3, CRN, and TRACER. Furthermore, the cosmic-ray source abundances are compared to a mixture of 80% solar system abundances and 20% massive stellar outflow (MSO) as a function of atomic mass. The good agreement with TIGER measurements at lower energies confirms the existence of a substantial fraction of MSO material required in the {approx}TeV per nucleon region.

Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Malinin, A. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Allison, P. S.; Beatty, J. J.; Brandt, T. J. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States); Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S. [Department of Physics, University of Siena and INFN, Via Roma 56, 53100 Siena (Italy); Barbier, L. [Astroparticle Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Childers, J. T.; DuVernois, M. A. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Conklin, N. B.; Coutu, S. [Department of Physics, Penn State University, University Park, PA 16802 (United States); Jeon, J. A.; Lee, J., E-mail: ipark@ewha.ac.k [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of)

2010-06-01T23:59:59.000Z

245

On the Possible Association of Ultra High Energy Cosmic Rays with Nearby Active Galaxies  

SciTech Connect

Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of cosmic rays (CRs) with energies >57 EeV that suggests a correlation with the positions of active galactic nuclei (AGN) located within {approx}75 Mpc. However, this analysis does not take into account AGN morphology. A detailed study of the sample of AGN whose positions correlate with the CR events shows that most of them are classified as Seyfert 2 and low-ionization nuclear emission-line region (LINER) galaxies which do not differ from other local AGN of the same types. Therefore, the claimed correlation between the CR events observed by the Pierre Auger Observatory and local active galaxies should be considered as resulting from a chance coincidence, if the production of the highest energy CRs is not episodic in nature, but operates in a single object on long ({ge} Myr) timescales. Additionally, most of the selected sources do not show significant jet activity, and hence--in the framework of the jet paradigm--there are no reasons for expecting them to accelerate CRs up to the highest energies, {approx}10{sup 20} eV, at all. If the extragalactic magnetic fields and the sources of these CRs are coupled with matter, it is possible that the deflection angle is larger than expected in the case of a uniform source distribution due to effectively larger fields. A future analysis has to take into account AGN morphology and may yield a correlation with a larger deflection angle and/or more distant sources. We further argue that Cen A alone could be associated with at least 4 events due to its large radio extent, and Cen B can be associated with more than 1 event due to its proximity to the Galactic plane and, correspondingly, the stronger Galactic magnetic field the ultra high energy CRs (UHECRs) encounter during propagation. If the UHECRs associated with these events are indeed accelerated by Cen A and Cen B, their deflection angles may provide information on the structure of the magnetic field in the direction of these putative sources. Future -ray observations (by, e.g., Gamma-Ray Large Area Space Telescope [GLAST], High Energy Stereoscopic System [HESS]) may provide additional clues to the nature of the accelerators of the UHECRs in the local Universe.

Moskalenko, Igor V.; Stawarz, Lukasz; Porter, Troy A.; Cheung, Chi C.

2008-05-14T23:59:59.000Z

246

The IceCube Collaboration:contributions to the 30 th International Cosmic Ray Conference (ICRC 2007),  

SciTech Connect

This paper bundles 40 contributions by the IceCube collaboration that were submitted to the 30th International Cosmic Ray Conference ICRC 2007. The articles cover studies on cosmic rays and atmospheric neutrinos, searches for non-localized, extraterrestrial {nu}{sub e}, {nu}{sub {mu}} and {nu}{sub {tau}} signals, scans for steady and intermittent neutrino point sources, searches for dark matter candidates, magnetic monopoles and other exotic particles, improvements in analysis techniques, as well as future detector extensions. The IceCube observatory will be finalized in 2011 to form a cubic-kilometer ice-Cherenkov detector at the location of the geographic South Pole. At the present state of construction, IceCube consists of 52 paired IceTop surface tanks and 22 IceCube strings with a total of 1426 Digital Optical Modules deployed at depths up to 2350 m. The observatory also integrates the 19 string AMANDA subdetector, that was completed in 2000 and extends IceCube's reach to lower energies. Before the deployment of IceTop, cosmic air showers were registered with the 30 station SPASE-2 surface array. IceCube's low noise Digital Optical Modules are very reliable, show a uniform response and record waveforms of arriving photons that are resolvable with nanosecond precision over a large dynamic range. Data acquisition, reconstruction and simulation software are running in production mode and the analyses, profiting from the improved data quality and increased overall sensitivity, are well under way.

IceCube Collaboration; Ackermann, M.

2007-11-02T23:59:59.000Z

247

Investigation of the relative abundance of heavy versus light nuclei in primary cosmic rays using underground muon bundles  

SciTech Connect

We study multiple muon events (muon bundles) recorded underground at a depth of 2090 mwe. To penetrate to this depth, the muons must have energies above 0.8 TeV at the Earth`s surface; the primary cosmic ray nuclei which give rise to the observed muon bundles have energies at incidence upon the upper atmosphere of 10 to 10{sup 5}TeV. The events are detected using the Soudan 2 experiment`s fine grained tracking calorimeter which is surrounded by a 14 m {times}10 m {times} 31 m proportional tube array (the ``active shield``). Muon bundles which have at least one muon traversing the calorimeter, are reconstructed using tracks in the calorimeter together with hit patterns in the proportional tube shield. All ionization pulses are required to be coincident within 3 microseconds. A goal of this study is to investigate the relative nuclear abundances in the primary cosmic radiation around the ``knee`` region (10{sup 3} {minus} 10{sup 4} TeV) of the incident energy spectrum. Four models for the nuclear composition of cosmic rays are considered: The Linsley model, the Constant Mass Composition model (CMC), the Maryland model and the Proton-poor model. A Monte Carlo which incorporates one model at a time is used to simulate events which are then reconstructed using the same computer algorithms that are used for the data. Identical cuts and selections are applied to the data and to the simulated events.

Sundaralingam, N.

1993-06-08T23:59:59.000Z

248

Star Formation History up to z = 7.4: Implications for Gamma-Ray Bursts and the Cosmic Metallicity Evolution  

E-Print Network (OSTI)

The current Swift sample of gamma-ray bursts (GRBs) with measured redshifts allows to test the assumption that GRBs trace the star formation in the Universe. Some authors have claimed that the rate of GRBs increases with cosmic redshift faster than the star formation rate, whose cause is not known yet. In this paper, I investigate the possibility for interpreting the observed discrepancy between the GRB rate history and the star formation rate history by the cosmic metallicity evolution, motivated by the observation that the cosmic metallicity evolves with redshift and GRBs prefer to occur in low metallicity galaxies. First, I derive a star formation history up to redshift z=7.4 from an updated sample of star formation rate densities obtained by adding the new UV measurements of Bouwens et al. and the new UV and infrared measurements of Reddy et al. to the existing sample compiled by Hopkins & Beacom. Then, adopting a simple model for the relation between the GRB production and the cosmic metallicity history as proposed by Langer & Norman, I show that the observed redshift distribution of the Swift GRBs can be reproduced with a fairly good accuracy. Although the results are limited by the small size of the GRB sample and the poorly understood selection biases in detection and localization of GRBs and in redshift determination, they suggest that GRBs trace both the star formation and the metallicity evolution. If the star formation history can be accurately measured with other approaches, which is presumably achievable in the near future, it will be possible to determine the cosmic metallicity evolution with the study on the redshift distribution of GRBs.

Li-Xin Li

2007-10-18T23:59:59.000Z

249

Magnetars in the Metagalaxy: An Origin for Ultra High Energy Cosmic Rays in the Nearby Universe  

E-Print Network (OSTI)

I show that the relativistic winds of newly born magnetars with khz initial spin rates, occurring in all normal galaxies, can accelerate ultrarelativistic light ions with an E^{-1} injection spectrum, steepening to E^{-2} at higher energies, with an upper cutoff above 10^{21} eV. Interactions with the CMB yield a spectrum in good accord with the observed spectrum of Ultra-High Energy Cosmic Rays (UHECR), if ~ 5-10% of the magnetars are born with voltages sufficiently high to accelerate the UHECR. The form the spectrum spectrum takes depends on the gravitational wave losses during the magnetars' early spindown - pure electromagnetic spindown yields a flattening of the E^3 J(E) spectrum below 10^{20} eV, while a moderate GZK ``cutoff'' appears if gravitational wave losses are strong enough. I outline the physics such that the high energy particles escape with small energy losses from a magnetar's natal supernova, including Rayleigh-Taylor ``shredding'' of the supernova envelope, expansion of a relativistic blast wave into the interstellar medium, acceleration of the UHE ions through surf-riding in the electromgnetic fields of the wind, and escape of the UHE ions in the rotational equator with negligible radiation loss. The abundance of interstellar supershells and unusually large supernova remnants suggests that most of the initial spindown energy is radiated in khz gravitational waves for several hours after each supernova, with effective strains from sources at typical distances ~ 3 x 10^{-21}. Such bursts of gravitational radiation should correlate with bursts of ultra-high energy particles. The Auger experiment should see such bursts every few years.

Jonathan Arons

2002-08-23T23:59:59.000Z

250

Blazing Cerenkov Flashes at the Horizons by Cosmic Rays and Neutrinos Induced Air-Showers  

E-Print Network (OSTI)

High Energy Cosmic Rays (C.R.) versus Neutrino and Neutralino induced Air-Shower maybe tested at Horizons by their muons, gamma and Cerenkov blazing signals. Inclined and Horizontal C.R. Showers (70-90 zenith angle) produce secondary (gamma, e+, e-) mostly suppressed by high column atmosphere depth. Earliest shower Cherenkov photons are diluted by large distances and by air opacity, while secondary penetrating muons and their successive decay into electrons and gamma, may revive additional Cerenkov lights. GeVs gamma telescopes at the top of the mountains or in Space may detect at horizons PeVs up to EeV C.R. and their secondaries. Details on arrival angle and column depth, shower shape, timing signature of photon flash intensity, may inform us on the altitude interaction and primary UHECR composition. Below the horizons, at zenith angle among copious single albedo muons, rare up-going showers traced by muon bundles would give evidence of rare tau Earth-Skimming neutrinos, at EeVs energies. Their rate may be comparable with 6.3 PeVs anti-neutrino electron induced air-shower (mostly hadronic) originated above and also below horizons, in interposed atmosphere by W resonance at Glashow peak. Additional and complementary UHE SUSY neutralinos at tens PeVs-EeV energy may blaze, by its characteristic electromagnetic signature. Their secondary shower blazing Cerenkov lights and distances might be disentangled from UHECR by Stereoscopic Telescopes such as Magic ones or Hess array experiment. The horizontal detection sensitivity of Magic in the present set up (if totally devoted to the Horizons Shower search) maybe already be comparable to AMANDA underground neutrino detector at PeVs energies.

D. Fargion

2004-12-21T23:59:59.000Z

251

Sky-maps of the sidereal anisotropy of galactic cosmic ray intensity and its energy dependence  

E-Print Network (OSTI)

We analyze the sidereal daily variations observed between 1985 and 2006 at Matsushiro, Japan (MAT) and between 1993 and 2005 at Liapootah, Tasmania (LPT). These stations comprise the two hemisphere network (THN) of underground muon detectors in Japan and Australia. Yearly mean harmonic vectors at MAT and LPT are more or less stable without any significant change in phase and amplitude in correlation with either the solar activity- or magnetic-cycles. In this paper, therefore, we analyze the average anisotropy over the entire observation periods, i.e. 1985-2006 for MAT and 1993-2005 for LPT. We apply to the THN data a best-fitting analysis based on a model anisotropy in space identical to that adopted by Amenomori et al. (2007) for Tibet III data. The median energies of primary cosmic rays recorded are ~0.5 TeV for THN and ~5 TeV for the Tibet III experiment. It is shown that the intensity distribution of the best-fit anisotropy is quite similar to that derived from Tibet III data, regardless of the order of magnitude difference in energies of primary particles. This, together with the THN observations, confirms that the analysis by Amenomori et al. (2007) based on the Tibet III experiment in the northern hemisphere is not seriously biased. The best-fit amplitudes of the anisotropy, on the other hand, are only one third or less of those reported by the Tibet III experiment, indicating attenuation due to solar modulation. The rigidity dependence of the anisotropy amplitude in the sub-TeV region is consistent with the spectrum reported by Hall et al. (1999), smoothly extending to the Tibet III result in the multi-TeV region. The amplitude at higher energies appears almost constant or gradually decreasing with increasing rigidity.

K. Munakata; N. Matsumoto; S. Yasue; C. Kato; S. Mori; M. Takita; M. L. Duldig; J. E. Humble; J. Kota

2008-11-04T23:59:59.000Z

252

Magnetic lensing of extremely high energy cosmic rays in a galactic wind  

E-Print Network (OSTI)

We show that in the model of Galactic magnetic wind recently proposed to explain the extremely high energy (EHE) cosmic rays so far observed as originating from a single source (M87 in the Virgo cluster), the magnetic field strongly magnifies the fluxes and produces multiple images of the source. The apparent position on Earth of the principal image moves, for decreasing energies, towards the galactic south. It is typically amplified by an order of magnitude at $E/Z\\sim 2\\times 10^{20}$ eV, but becomes strongly demagnified below $10^{20}$ eV. At energies below $E/Z\\sim 1.3\\times 10^{20}$ eV, all events in the northern galactic hemisphere are due to secondary images, which have huge amplifications ($>10^2$). This model would imply strong asymmetries between the north and south galactic hemispheres, such as a (latitude dependent) upper cut-off value below $2\\times 10^{20}$ eV for CR protons arriving to the south and lower fluxes in the south than in the north above $10^{20}$ eV. The large resulting magnifications reduce the power requirements on the source, but the model needs a significant tunning between the direction to the source and the symmetry axis of the wind. If more modest magnetic field strengths were assumed, a scenario in which the observed EHE events are heavier nuclei whose flux is strongly lensed becomes also plausible and would predict that a transition from a light composition to a heavier one could take place at the highest energies.

Diego Harari; Silvia Mollerach; Esteban Roulet

2000-05-24T23:59:59.000Z

253

Analytic calculations of the spectra of ultra high energy cosmic ray nuclei. II. The general case of background radiation  

E-Print Network (OSTI)

We discuss the problem of ultra high energy nuclei propagation in extragalactic background radiations. The present paper is the continuation of the accompanying paper I where we have presented three new analytic methods to calculate the fluxes and spectra of Ultra High Energy Cosmic Ray (UHECR) nuclei, both primary and secondary, and secondary protons. The computation scheme in this paper is based on the analytic solution of coupled kinetic equations, which takes into account the continuous energy losses due to the expansion of the universe and pair-production, together with photo-disintegration of the nuclei. This method includes in the most natural way the production of secondary nuclei in the process of photo-disintegration of the primary nuclei during their propagation through extragalactic background radiations. In paper I, in order to present the suggested analytical schemes of calculations, we have considered only the case of the Cosmic Microwave Background (CMB) radiation, in the present paper we gene...

Aloisio, R; Grigorieva, S

2013-01-01T23:59:59.000Z

254

Section on Supernova remnants and cosmic rays of the White Paper on the Status and Future of Ground-based Gamma-ray Astronomy  

E-Print Network (OSTI)

This is a report on the findings of the SNR/cosmic-ray working group for the white paper on the status and future of ground-based gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be found on astro-ph. This detailed section of the white paper discusses the status of past and current attempts to observe shell-type supernova remnants and diffuse emission from cosmic rays at GeV-TeV energies. We concentrate on the potential of future ground-based gamma-ray experiments to study the acceleration of relativistic charged particles which is one of the main unsolved, yet fundamental, problems in modern astrophysics. The acceleration of particles relies on interactions between energetic particles and magnetic turbulence. In the case of SNRs we can perform spatially resolved studies in systems with known geometry, and the plasma physics deduced from these observations will help us to understand other systems where rapid particle acceleration is b...

Pohl, M; Atoyan, A; Baring, M; Beacom, J; Blandford, R; Butt, Y; Bykov, A; Ellison, D; Funk, S; Halzen, F; Hays, E; Humensky, B; Jones, T; Kaaret, Philip; Kieda, D; Le Bohec, S; Mészáros, P; Moskalenko, I; Slane, P; Strong, A; Wakely, S

2008-01-01T23:59:59.000Z

255

Section on Supernova Remnants and Cosmic Rays of the White Paper on the Status and Future of Ground-Based Gamma-Ray Astronomy  

SciTech Connect

This is a report on the findings of the SNR/cosmic-ray working group for the white paper on the status and future of ground-based gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be found on astro-ph. This detailed section of the white paper discusses the status of past and current attempts to observe shell-type supernova remnants and diffuse emission from cosmic rays at GeV-TeV energies. We concentrate on the potential of future ground-based gamma-ray experiments to study the acceleration of relativistic charged particles which is one of the main unsolved, yet fundamental, problems in modern astrophysics. The acceleration of particles relies on interactions between energetic particles and magnetic turbulence. In the case of SNRs we can perform spatially resolved studies in systems with known geometry, and the plasma physics deduced from these observations will help us to understand other systems where rapid particle acceleration is believed to occur and where observations as detailed as those of SNRs are not possible.

Pohl, M.; /Iowa State U.; Abdo, Aous A.; /Michigan State U.; Atoyan, A.; /McGill U.; Baring, Matthew G.; /Rice U.; Beacom, John Francis; /Ohio State U.; Blandford, R.; /SLAC; Butt, Y.; /Harvard-Smithsonian Ctr. Astrophys.; Bykov, A.; /Ioffe Phys. Tech. Inst.; Ellison, D.; /North Carolina State U.; Funk, S.; /SLAC; Halzen, Francis L.; /Wisconsin U., Madison; Hays, Elizabeth A.; /NASA, Goddard; Humensky, B.; /Chicago U., EFI; Jones, T.; /Minnesota U.; Kaaret, P.; /Iowa State U.; Kieda, David B.; /Utah U.; LeBohec, S.; /Utah U.; Meszaros, Peter; /Penn State U.; Moskalenko, Igor Vladimirovich; /SLAC; Slane, P.; /Harvard-Smithsonian Ctr. Astrophys.; Strong, A.; /Garching, Max Planck Inst., MPE /Chicago U., EFI

2011-11-09T23:59:59.000Z

256

Section on Supernova remnants and cosmic rays of the White Paper on the Status and Future of Ground-based Gamma-ray Astronomy  

E-Print Network (OSTI)

This is a report on the findings of the SNR/cosmic-ray working group for the white paper on the status and future of ground-based gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be found on astro-ph. This detailed section of the white paper discusses the status of past and current attempts to observe shell-type supernova remnants and diffuse emission from cosmic rays at GeV-TeV energies. We concentrate on the potential of future ground-based gamma-ray experiments to study the acceleration of relativistic charged particles which is one of the main unsolved, yet fundamental, problems in modern astrophysics. The acceleration of particles relies on interactions between energetic particles and magnetic turbulence. In the case of SNRs we can perform spatially resolved studies in systems with known geometry, and the plasma physics deduced from these observations will help us to understand other systems where rapid particle acceleration is believed to occur and where observations as detailed as those of SNRs are not possible.

M. Pohl; A. Abdo; A. Atoyan; M. Baring; J. Beacom; R. Blandford; Y. Butt; A. Bykov; D. Ellison; S. Funk; F. Halzen; E. Hays; B. Humensky; T. Jones; P. Kaaret; D. Kieda; S. LeBohec; P. Meszaros; I. Moskalenko; P. Slane; A. Strong; S. Wakely

2008-10-03T23:59:59.000Z

257

A study of the ultrahigh-energy cosmic ray mass composition with the MACRO and EAS-TOP experiments  

SciTech Connect

Two components of cosmic-ray-induced air showers are measured simultaneously at the Gran Sasso Laboratory: the electromagnetic shower at the ground surface by the EAS-TOP extensive air shower array, and the deep-underground muons by the MACRO experiment. The two independent data sets collected during 96.3 days of simultaneous running are combined, and underground muon multiplicity distributions are obtained for anticoincident events (no surface trigger) and high-energy, coincident events. These categories correspond to ranges in primary energy from about 2 x 10{sup 3} GeV to a few times 10{sup 5} GeV, and from 1.5 x 10{sup 5} GeV to about 10{sup 7} GeV, respectively. The experimental shower size and muon multiplicity distributions, as well as the distribution of mean muon multiplicity as a function of shower size (N{sub mu} - log(N{sub mu}) relation), are compared to the ones obtained with Monte Carlo calculations using various trial compositions as input. This is done in an effort to discriminate between these models of primary cosmic-ray mass composition at and above the `kneel` in the all-particle spectrum, where contradictory experimental evidence exists and where a knowledge of the composition would bear upon possible mechanisms for cosmic-ray acceleration and propagation. Detailed studies of simulated anticoincident event rates uncover problems with generator used, with between 25 and 40% too few high-energy muons created. This, combined with the dependence of absolute event rates on the assumed differential primary energy spectra, hampers the interpretation in terms of composition of underground muon or surface air shower data taken separately. However, the N{sub mu} - log(N{sub e}) relation is independent of the spectra or overall Monte Carlo normalization problems. The simulated N{sub mu} - log (N{sub e}) relation for coincident events is found to be inconsistent with the possibility that the cosmic ray flux becomes proton-dominated at and above the knee.

Coutu, S.

1993-12-31T23:59:59.000Z

258

Relative Damaging Ability Of Galactic Cosmic Rays Determined Using Monte Carlo Simulations Of Track Structure  

E-Print Network (OSTI)

The energy deposition characteristics of heavy ions vary substantially compared to those of photons. Many radiation biology studies have compared the damaging effects of different types of radiation to establish relative biological effectiveness among them. These studies are dependent on cell type, biological endpoint, radiation type, dose, and dose rate. The radiation field found in space is much more complicated than that simulated in most experiments, both from a point of dose-rate as well as the highly mixed field of radiative particles encompassing a broad spectrum of energies. To establish better estimates for radiation risks on long-term, deep space missions, the damaging ability of heavy ions requires further understanding. Track structure studies provide significant details about the spatial distribution of energy deposition events in and around the sensitive targets of a mammalian cell. The damage imparted by one heavy ion relative to another can be established by modeling the track structures of ions that make up the galactic cosmic ray (GCR) spectrum and emphasizing biologically relevant target geometries. This research was undertaken to provide a better understanding of the damaging ability of GCR at the cellular level. By comparing ions with equal stopping power values, the differences in track structure will illuminate variations in cell particle traversals and ionization density within cell nuclei. For a cellular target, increased particle traversals, along with increased ionization density, are key identifiers for increased damaging ability. Performing Monte Carlo simulations with the computer code, FLUKA, this research will provide cellular dosimetry data and detail the track structure of the ions. As shown in radiobiology studies, increased ionizations within a cell nucleus generally lead to increased DNA breaks and increased free radical production, resulting in increased carcinogenesis and cell death. The spatial distribution of dose surrounding ions tracks are compared for inter- and intracellular regions. A comparison can be made for many different ions based upon dose and particle fluence across those different regions to predict relative damaging ability. This information can be used to improve estimates for radiation quality and dose equivalent from the space radiation environment.

Cox, Bradley

2011-08-01T23:59:59.000Z

259

Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment  

E-Print Network (OSTI)

We present new measurements of heavy cosmic-ray nuclei at high energies per- formed during the first flight of the balloon-borne cosmic-ray experiment CREAM (Cosmic-Ray Energetics And Mass). This instrument uses multiple charge detectors and a transition radiation detector to provide the first high accuracy measurements of the relative abundances of elements from boron to oxygen up to energies around 1 TeV/n. The data agree with previous measurements at lower energies and show a relatively steep decline (~E$^-0.6$ to E$^-0.5$) at high energies. They further show the source abundance of nitrogen relative to oxygen is ~10% in the TeV/n region.

H. S. Ahn; P. S. Allison; M. G. Bagliesi; J. J. Beatty; G. Bigongiari; P. J. Boyle; T. J. Brandt; J. T. Childers; N. B. Conklin; S. Coutu; M. A. Duvernois; O. Ganel; J. H. Han; H. J. Hyun; J. A. Jeon; K. C. Kim; J. K. Lee; M. H. Lee; L. Lutz; P. Maestro; A. Malinin; P. S. Marrocchesi; S. A. Minnick; S. I. Mognet; S. Nam; S. L. Nutter; I. H. Park; N. H. Park; E. S. Seo; R. Sina; S. P. Swordy; S. P. Wakely; J. Wu; J. Yang; Y. S. Yoon; R. Zei; S. Y. Zinn

2008-08-12T23:59:59.000Z

260

LARGE-SCALE DISTRIBUTION OF ARRIVAL DIRECTIONS OF COSMIC RAYS DETECTED ABOVE 10{sup 18} eV AT THE PIERRE AUGER OBSERVATORY  

SciTech Connect

A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10{sup 18} eV at the Pierre Auger Observatory is presented. This search is performed as a function of both declination and right ascension in several energy ranges above 10{sup 18} eV, and reported in terms of dipolar and quadrupolar coefficients. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Assuming that any cosmic-ray anisotropy is dominated by dipole and quadrupole moments in this energy range, upper limits on their amplitudes are derived. These upper limits allow us to test the origin of cosmic rays above 10{sup 18} eV from stationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in all directions.

Abreu, P.; Andringa, S. [LIP and Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Aglietta, M. [Istituto di Fisica dello Spazio Interplanetario (INAF), Universita di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E. J. [Fermilab, Batavia, IL (United States); Albuquerque, I. F. M. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Allard, D. [Laboratoire AstroParticule et Cosmologie (APC), Universite Paris 7, CNRS-IN2P3, Paris (France); Allekotte, I. [Centro Atomico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Facultad Regional Buenos Aires, Universidad Tecnologica Nacional, Buenos Aires (Argentina); Alvarez Castillo, J. [Universidad Nacional Autonoma de Mexico, Mexico, D. F. (Mexico); Alvarez-Muniz, J. [Universidad de Santiago de Compostela (Spain); Alves Batista, R. [IFGW, Universidade Estadual de Campinas, Campinas, SP (Brazil); Ambrosio, M.; Aramo, C. [Universita di Napoli 'Federico II' and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Antici'c, T. [Rudjer Boskovi'c Institute, 10000 Zagreb (Croatia); Arganda, E. [IFLP, Universidad Nacional de La Plata and CONICET, La Plata (Argentina); Collaboration: Pierre Auger Collaboration; and others

2012-12-15T23:59:59.000Z

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261

CONSTRAINTS ON THE ORIGIN OF COSMIC RAYS ABOVE 10{sup 18} eV FROM LARGE-SCALE ANISOTROPY SEARCHES IN DATA OF THE PIERRE AUGER OBSERVATORY  

SciTech Connect

A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10{sup 18} eV at the Pierre Auger Observatory is reported. For the first time, these large-scale anisotropy searches are performed as a function of both the right ascension and the declination and expressed in terms of dipole and quadrupole moments. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Upper limits on dipole and quadrupole amplitudes are derived under the hypothesis that any cosmic ray anisotropy is dominated by such moments in this energy range. These upper limits provide constraints on the production of cosmic rays above 10{sup 18} eV, since they allow us to challenge an origin from stationary galactic sources densely distributed in the galactic disk and emitting predominantly light particles in all directions.

Abreu, P.; Andringa, S. [LIP and Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Aglietta, M. [Istituto di Fisica dello Spazio Interplanetario (INAF), Universita di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E. J. [Fermilab, Batavia, IL (United States); Albuquerque, I. F. M. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Allard, D. [Laboratoire AstroParticule et Cosmologie (APC), Universite Paris 7, CNRS-IN2P3, Paris (France); Allekotte, I. [Centro Atomico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Universidad Tecnologica Nacional - Facultad Regional Buenos Aires, Buenos Aires (Argentina); Castillo, J. Alvarez [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Alvarez-Muniz, J. [Universidad de Santiago de Compostela (Spain); Alves Batista, R. [Universidade Estadual de Campinas, IFGW, Campinas, SP (Brazil); Ambrosio, M.; Aramo, C. [Universita di Napoli 'Federico II' and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Antici'c, T. [Rudjer Boskovi'c Institute, 10000 Zagreb (Croatia); Arganda, E. [IFLP, Universidad Nacional de La Plata and CONICET, La Plata (Argentina); Collaboration: Pierre Auger Collaboration; and others

2013-01-01T23:59:59.000Z

262

A study of the link between cosmic rays and clouds with a cloud chamber at the CERN PS  

E-Print Network (OSTI)

Recent satellite data have revealed a surprising correlation between galactic cosmic ray (GCR) intensity and the fraction of the Earth covered by clouds. If this correlation were to be established by a causal mechanism, it could provide a crucial step in understanding the long-sought mechanism connecting solar and climate variability. The Earth's climate seems to be remarkably sensitive to solar activity, but variations of the Sun's electromagnetic radiation appear to be too small to account for the observed climate variability. However, since the GCR intensity is strongly modulated by the solar wind, a GCR-cloud link may provide a sufficient amplifying mechanism. Moreover if this connection were to be confirmed, it could have profound consequences for our understanding of the solar contributions to the current global warming. The CLOUD (Cosmics Leaving OUtdoor Droplets) project proposes to test experimentally the existence a link between cosmic rays and cloud formation, and to understand the microphysical mechanism. CLOUD plans to perform detailed laboratory measurements in a particle beam at CERN, where all the parameters can be precisely controlled and measured. The beam will pass through an expansion cloud chamber and a reactor chamber where the atmosphere is to be duplicated by moist air charged with selected aerosols and trace condensable vapours. An array of external detectors and mass spectrometers is used to analyse the physical and chemical characteristics of the aerosols and trace gases during beam exposure. Where beam effects are found, the experiment will seek to evaluate their significance in the atmosphere by incorporating them into aerosol and cloud models.

The Cloud Collaboration

2001-04-16T23:59:59.000Z

263

33RD INTERNATIONAL COSMIC RAY CONFERENCE, RIO DE JANEIRO 2013 THE ASTROPARTICLE PHYSICS CONFERENCE  

E-Print Network (OSTI)

ilpark@skku.edu, mahuang@nuu.edu.tw Abstract: Gamma-Ray Bursts (GRBs) are the most energetic explosions. We will present the latest progress in this conference. Keywords: Gamma Ray Burst, Satellite Instruments, Coded mask, X rays 1 Gamma-Ray Burst Prompt Signal First discovered in in 1967, Gamma-Ray Bursts

264

Similarities and Distinctions in Cosmic-Ray Modulation during Different Phases of Solar and Magnetic Activity Cycles  

E-Print Network (OSTI)

We study the solar-activity and solar-polarity dependence of galactic cosmic-ray intensity (CRI) on the solar and heliospheric parameters playing a significant role in solar modulation. We utilize the data for cosmic-ray intensity as measured by neutron monitors, solar activity as measured by sunspot number (SSN), interplanetary plasma/field parameters, solar-wind velocity [V] and magnetic field [B], as well as the tilt of the heliospheric current sheet [{\\Lambda}] and analyse these data for Solar Cycles 20 - 24 (1965 - 2011). We divide individual Solar Cycles into four phases, i.e. low, high, increasing, and decreasing solar activity. We perform regression analysis to calculate and compare the CRI-response to changes in different solar/interplanetary parameters during (i) different phases of solar activity and (ii) similar activity phases but different polarity states. We find that the CRI-response is different during negative (A0) polarity states not only with SSN and {\\Lambda} but also with B and V. The re...

Aslam, O P M

2013-01-01T23:59:59.000Z

265

Mapping of the cosmic ray events related to the solar activity for the period 2003-2005  

E-Print Network (OSTI)

The relationship between cosmic ray intensity decreases and solar events is still an open field of space research. In this work a complete study of solar events occurred from January 2003 to December 2005, is considered. This three-years time period characterized by an unexpected activity of the Sun was divided into 27-day intervals starting from BR 2313 (06.01.2003) to 2353 (21.12.2005), generating diagrams of the cosmic ray intensity data recorded at the Athens Neutron Monitor Station. This station is working at an altitude of 260m and cut-off rigidity 8.53GV provided to the Internet high-resolution data in real-time. A mapping of all available solar and interplanetary events, such as solar flares with importance M and X, coronal mass ejections (Halo and Partial) was done. As we are going down from the solar maximum to the declining phase of the 23rd solar cycle, a statistical overview of the corresponding relationship among these phenomena, the significant percentage of the connection of Halo CMEs and sola...

Papaioannou, A; Mavromichalaki, H

2010-01-01T23:59:59.000Z

266

Fermi LAT observations of cosmic-ray electrons from 7 GeV to 1 TeV  

SciTech Connect

We present the results of our analysis of cosmic-ray electrons using about 8x10{sup 6} electron candidates detected in the first 12 months on-orbit by the Fermi Large Area Telescope. This work extends our previously published cosmic-ray electron spectrum down to 7 GeV, giving a spectral range of approximately 2.5 decades up to 1 TeV. We describe in detail the analysis and its validation using beam-test and on-orbit data. In addition, we describe the spectrum measured via a subset of events selected for the best energy resolution as a cross-check on the measurement using the full event sample. Our electron spectrum can be described with a power law {proportional_to}E{sup -3.08{+-}0.05} with no prominent spectral features within systematic uncertainties. Within the limits of our uncertainties, we can accommodate a slight spectral hardening at around 100 GeV and a slight softening above 500 GeV.

Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bogart, J. R.; Borgland, A. W.; Buehler, R.; Cameron, R. A.; Charles, E.; Chiang, J.; Claus, R.; Digel, S. W.; Couto e Silva, E. do; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Funk, S.; Glanzman, T. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94305 (United States)

2010-11-01T23:59:59.000Z

267

InteliSolar | Open Energy Information  

Open Energy Info (EERE)

InteliSolar InteliSolar Jump to: navigation, search 200px Name InteliSolar Address 5201 Great America Pkwy Ste 320 Place Santa Clara, California Zip 95054 Sector Efficiency, Renewable Energy, Services, Solar, Wind energy Product Renewable Energy Systems using solar or wind energy Year founded 2009 Number of employees 1-10 Phone number 1-877-837-6527 Website http://www.intelisolar.com Coordinates 37.406011°, -121.976759° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.406011,"lon":-121.976759,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

268

Formation of electrostatic structures by wakefield acceleration in ultrarelativistic plasma flows: Electron acceleration to cosmic ray energies  

SciTech Connect

The ever increasing performance of supercomputers is now enabling kinetic simulations of extreme astrophysical and laser produced plasmas. Three-dimensional particle-in-cell (PIC) simulations of relativistic shocks have revealed highly filamented spatial structures and their ability to accelerate particles to ultrarelativistic speeds. However, these PIC simulations have not yet revealed mechanisms that could produce particles with tera-electron volt energies and beyond. In this work, PIC simulations in one dimension (1D) of the foreshock region of an internal shock in a gamma ray burst are performed to address this issue. The large spatiotemporal range accessible to a 1D simulation enables the self-consistent evolution of proton phase space structures that can accelerate particles to giga-electron volt energies in the jet frame of reference, and to tens of tera-electron volt in the Earth's frame of reference. One potential source of ultrahigh energy cosmic rays may thus be the thermalization of relativistically moving plasma.

Dieckmann, M.E.; Shukla, P.K.; Eliasson, B. [Institute of Theoretical Physics IV, Ruhr-University Bochum, D-44780 Bochum (Germany)

2006-06-15T23:59:59.000Z

269

Commissioning of the ATLAS Trigger and Data Acquisition System with Single-Beam and Cosmic Rays  

E-Print Network (OSTI)

ATLAS is one of the two general purpose detectors at the Large Hadron Collider (LHC). It's three-level Trigger and DAQ system (TDAQ) has to investigate a huge rate of events and retain only the potentially interesting ones. We give an overview of the system and the early experience gained during LHC single-beam operation in 2008 and commissioning with cosmic data. Results on system functionality and performance based on preselected simulated events will be also presented.

Hauser, R; The ATLAS collaboration

2010-01-01T23:59:59.000Z

270

DOE Solar Decathlon: News Blog » Florida Int'l  

NLE Websites -- All DOE Office Websites (Extended Search)

Florida Int'l Below you will find Solar Decathlon news from the Florida Int'l archive, sorted by date. Video Blog: End of Assembly Tuesday, September 20, 2011 U.S. Department of...

271

A celestial gamma-ray foreground due to the albedo of small solar system bodies and a remote probe of the interstellar cosmic ray spectrum  

E-Print Network (OSTI)

We calculate the gamma-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids (MBAs), Jovian and Neptunian Trojan asteroids, and Kuiper Belt objects (KBOs) using the Moon as a template. We show that the gamma-ray albedo for the Main Belt, Trojans, and Kuiper Belt strongly depends on the small-body size distribution of each system. Based on an analysis of the Energetic Gamma Ray Experiment Telescope (EGRET) data we infer that the diffuse emission from the MBAs, Trojans, and KBOs has an integrated flux of less than ~6x10^{-6} cm^{-2} s^{-1} (100-500 MeV), which corresponds to ~12 times the Lunar albedo, and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). If detected by GLAST, it can provide unique direct information about the number of small bodies in each system that is difficult to assess by any other method. Additionally, the KBO albedo flux can be used to probe the spectrum of CR nuclei at close-to-interstellar conditions. The orbits of MBAs, Trojans, and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. Therefore, the asteroid gamma-ray albedo has to be taken into account when analyzing weak gamma-ray sources close to the ecliptic, especially near the Galactic center and for signals at high Galactic latitudes, such as the extragalactic gamma-ray emission. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center.

Igor V. Moskalenko; Troy A. Porter; Seth W. Digel; Peter F. Michelson; Jonathan F. Ormes

2007-12-12T23:59:59.000Z

272

The Morphology of the Galactic Dark Matter Synchrotron Emission with Self-Consistent Cosmic Ray Diffusion Models  

E-Print Network (OSTI)

A generic prediction in the paradigm of weakly interacting dark matter is the production of relativistic particles from dark matter pair-annihilation in regions of high dark matter density. Ultra-relativistic electrons and positrons produced in the center of the Galaxy by dark matter annihilation should produce a diffuse synchrotron emission. While the spectral shape of the synchrotron dark matter haze depends on the particle model (and secondarily on the galactic magnetic fields), the morphology of the haze depends primarily on (1) the dark matter density distribution, (2) the galactic magnetic field morphology, and (3) the diffusion model for high-energy cosmic-ray leptons. Interestingly, an unidentified excess of microwave radiation with characteristics similar to those predicted by dark matter models has been claimed to exist near the galactic center region in the data reported by the WMAP satellite, and dubbed the "WMAP haze". In this study, we carry out a self-consistent treatment of the variables enumerated above, enforcing constraints from the available data on cosmic rays, radio surveys and diffuse gamma rays. We outline and make predictions for the general morphology and spectral features of a "dark matter haze" and we compare them to the WMAP haze data. We also characterize and study the spectrum and spatial distribution of the inverse Compton emission resulting from the same population of energetic electrons and positrons. We point out that the spectrum and morphology of the radio emission at different frequencies is a powerful diagnostics to test whether a galactic synchrotron haze indeed originates from dark matter annihilation.

Tim Linden; Stefano Profumo; Brandon Anderson

2010-04-22T23:59:59.000Z

273

CHEMICAL ANALYSIS OF A DIFFUSE CLOUD ALONG A LINE OF SIGHT TOWARD W51: MOLECULAR FRACTION AND COSMIC-RAY IONIZATION RATE  

Science Conference Proceedings (OSTI)

Absorption lines from the molecules OH{sup +}, H{sub 2}O{sup +}, and H{sup +} {sub 3} have been observed in a diffuse molecular cloud along a line of sight near W51 IRS2. We present the first chemical analysis that combines the information provided by all three of these species. Together, OH{sup +} and H{sub 2}O{sup +} are used to determine the molecular hydrogen fraction in the outskirts of the observed cloud, as well as the cosmic-ray ionization rate of atomic hydrogen. H{sup +} {sub 3} is used to infer the cosmic-ray ionization rate of H{sub 2} in the molecular interior of the cloud, which we find to be {zeta}{sub 2} = (4.8 {+-} 3.4) Multiplication-Sign 10{sup -16} s{sup -1}. Combining the results from all three species we find an efficiency factor-defined as the ratio of the formation rate of OH{sup +} to the cosmic-ray ionization rate of H-of {epsilon} = 0.07 {+-} 0.04, much lower than predicted by chemical models. This is an important step in the future use of OH{sup +} and H{sub 2}O{sup +} on their own as tracers of the cosmic-ray ionization rate.

Indriolo, Nick; Neufeld, D. A. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Gerin, M. [LERMA, CNRS, Observatoire de Paris and ENS, F-75231 Paris Cedex 05 (France); Geballe, T. R. [Gemini Observatory, Hilo, HI 96720 (United States); Black, J. H. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Menten, K. M. [MPI fuer Radioastronomie, D-53121 Bonn (Germany); Goicoechea, J. R. [Departamento de Astrofisica, Centro de Astrobiologia (CSIC-INTA), E-28850 Madrid (Spain)

2012-10-20T23:59:59.000Z

274

INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth  

E-Print Network (OSTI)

We study the spectrum of the cosmic X-ray background (CXB) in energy range $\\sim$5-100 keV. Early in 2006 the INTEGRAL observatory performed a series of four 30ksec observations with the Earth disk crossing the field of view of the instruments. The modulation of the aperture flux due to occultation of extragalactic objects by the Earth disk was used to obtain the spectrum of the Cosmic X-ray Background(CXB). Various sources of contamination were evaluated, including compact sources, Galactic Ridge emission, CXB reflection by the Earth atmosphere, cosmic ray induced emission by the Earth atmosphere and the Earth auroral emission. The spectrum of the cosmic X-ray background in the energy band 5-100 keV is obtained. The shape of the spectrum is consistent with that obtained previously by the HEAO-1 observatory, while the normalization is $\\sim$10% higher. This difference in normalization can (at least partly) be traced to the different assumptions on the absolute flux from the Crab Nebulae. The increase relative to the earlier adopted value of the absolute flux of the CXB near the energy of maximum luminosity (20-50 keV) has direct implications for the energy release of supermassive black holes in the Universe and their growth at the epoch of the CXB origin.

E. Churazov; R. Sunyaev; M. Revnivtsev; S. Sazonov; S. Molkov; S. Grebenev; C. Winkler; A. Parmar; A. Bazzano; M. Falanga; A. Gros; F. Lebrun; L. Natalucci; P. Ubertini; J. -P. Roques; L. Bouchet; E. Jourdain; J. Knoedlseder; R. Diehl; C. Budtz-Jorgensen; S. Brandt; N. Lund; N. J. Westergaard; A. Neronov; M. Turler; M. Chernyakova; R. Walter; N. Produit; N. Mowlavi; J. M. Mas-Hesse; A. Domingo; N. Gehrels; E. Kuulkers; P. Kretschmar; M. Schmidt

2006-08-11T23:59:59.000Z

275

Moon Shadow by Cosmic Rays under the Influence of Geomagnetic Field and Search for Antiprotons at Multi-TeV Energies  

E-Print Network (OSTI)

We have observed the shadowing of galactic cosmic ray flux in the direction of the moon, the so-called moon shadow, using the Tibet-III air shower array operating at Yangbajing (4300 m a.s.l.) in Tibet since 1999. Almost all cosmic rays are positively charged; for that reason, they are bent by the geomagnetic field, thereby shifting the moon shadow westward. The cosmic rays will also produce an additional shadow in the eastward direction of the moon if cosmic rays contain negatively charged particles, such as antiprotons, with some fraction. We selected 1.5 x10^{10} air shower events with energy beyond about 3 TeV from the dataset observed by the Tibet-III air shower array and detected the moon shadow at $\\sim 40 \\sigma$ level. The center of the moon was detected in the direction away from the apparent center of the moon by 0.23$^\\circ$ to the west. Based on these data and a full Monte Carlo simulation, we searched for the existence of the shadow produced by antiprotons at the multi-TeV energy region. No evidence of the existence of antiprotons was found in this energy region. We obtained the 90% confidence level upper limit of the flux ratio of antiprotons to protons as 7% at multi-TeV energies.

The Tibet AS Gamma Collaboration; M. Amenomori

2007-07-23T23:59:59.000Z

276

Probing the origin of cosmic-rays with extremely high energy neutrinos using the IceCube Observatory  

E-Print Network (OSTI)

We have searched for extremely high energy neutrinos using data taken with the IceCube detector between May 2010 and May 2012. Two neutrino induced particle shower events with energies around 1 PeV were observed, as reported previously. In this work, we investigate whether these events could originate from cosmogenic neutrinos produced in the interactions of ultra-high energy cosmic-rays with ambient photons while propagating through intergalactic space. Exploiting IceCube's large exposure for extremely high energy neutrinos and the lack of observed events above 100 PeV, we can rule out the corresponding models at more than 90% confidence level. The model independent quasi-differential 90% CL upper limit, which amounts to $E^2 \\phi_{\

IceCube Collaboration; M. G. Aartsen; R. Abbasi; M. Ackermann; J. Adams; J. A. Aguilar; M. Ahlers; D. Altmann; C. Arguelles; J. Auffenberg; X. Bai; M. Baker; S. W. Barwick; V. Baum; R. Bay; J. J. Beatty; J. Becker Tjus; K. -H. Becker; S. BenZvi; P. Berghaus; D. Berley; E. Bernardini; A. Bernhard; D. Z. Besson; G. Binder; D. Bindig; M. Bissok; E. Blaufuss; J. Blumenthal; D. J. Boersma; C. Bohm; D. Bose; S. Böser; O. Botner; L. Brayeur; H. -P. Bretz; A. M. Brown; R. Bruijn; J. Casey; M. Casier; D. Chirkin; A. Christov; B. Christy; K. Clark; F. Clevermann; S. Coenders; S. Cohen; D. F. Cowen; A. H. Cruz Silva; M. Danninger; J. Daughhetee; J. C. Davis; M. Day; C. De Clercq; S. De Ridder; P. Desiati; K. D. de Vries; M. de With; T. DeYoung; J. C. Díaz-Vélez; M. Dunkman; R. Eagan; B. Eberhardt; J. Eisch; S. Euler; P. A. Evenson; O. Fadiran; A. R. Fazely; A. Fedynitch; J. Feintzeig; T. Feusels; K. Filimonov; C. Finley; T. Fischer-Wasels; S. Flis; A. Franckowiak; K. Frantzen; T. Fuchs; T. K. Gaisser; J. Gallagher; L. Gerhardt; L. Gladstone; T. Glüsenkamp; A. Goldschmidt; G. Golup; J. G. Gonzalez; J. A. Goodman; D. Góra; D. T. Grandmont; D. Grant; P. Gretskov; J. C. Groh; A. Groß; C. Ha; A. Haj Ismail; P. Hallen; A. Hallgren; F. Halzen; K. Hanson; D. Heereman; D. Heinen; K. Helbing; R. Hellauer; S. Hickford; G. C. Hill; K. D. Hoffman; R. Hoffmann; A. Homeier; K. Hoshina; W. Huelsnitz; P. O. Hulth; K. Hultqvist; S. Hussain; A. Ishihara; E. Jacobi; J. Jacobsen; K. Jagielski; G. S. Japaridze; K. Jero; O. Jlelati; B. Kaminsky; A. Kappes; T. Karg; A. Karle; M. Kauer; J. L. Kelley; J. Kiryluk; J. Kläs; S. R. Klein; J. -H. Köhne; G. Kohnen; H. Kolanoski; L. Köpke; C. Kopper; S. Kopper; D. J. Koskinen; M. Kowalski; M. Krasberg; A. Kriesten; K. Krings; G. Kroll; J. Kunnen; N. Kurahashi; T. Kuwabara; M. Labare; H. Landsman; M. J. Larson; M. Lesiak-Bzdak; M. Leuermann; J. Leute; J. Lünemann; O. Macías; J. Madsen; G. Maggi; R. Maruyama; K. Mase; H. S. Matis; F. McNally; K. Meagher; M. Merck; T. Meures; S. Miarecki; E. Middell; N. Milke; J. Miller; L. Mohrmann; T. Montaruli; R. Morse; R. Nahnhauer; U. Naumann; H. Niederhausen; S. C. Nowicki; D. R. Nygren; A. Obertacke; S. Odrowski; A. Olivas; A. Omairat; A. O'Murchadha; L. Paul; J. A. Pepper; C. Pérez de los Heros; C. Pfendner; D. Pieloth; D. Pieloth; E. Pinat; J. Posselt; P. B. Price; G. T. Przybylski; L. Rädel; M. Rameez; K. Rawlins; P. Redl; R. Reimann; E. Resconi; W. Rhode; M. Ribordy; M. Richman; B. Riedel; J. P. Rodrigues; C. Rott; T. Ruhe; B. Ruzybayev; D. Ryckbosch; S. M. Saba; H. -G. Sander; M. Santander; S. Sarkar; K. Schatto; F. Scheriau; T. Schmidt; M. Schmitz; S. Schoenen; S. Schöneberg; A. Schönwald; A. Schukraft; L. Schulte; O. Schulz; D. Seckel; Y. Sestayo; S. Seunarine; R. Shanidze; C. Sheremata; M. W. E. Smith; D. Soldin; G. M. Spiczak; C. Spiering; M. Stamatikos; T. Stanev; N. A. Stanisha; A. Stasik; T. Stezelberger; R. G. Stokstad; A. Stößl; E. A. Strahler; R. Ström; G. W. Sullivan; H. Taavola; I. Taboada; A. Tamburro; A. Tepe; S. Ter-Antonyan; G. Teši?; S. Tilav; P. A. Toale; M. N. Tobin; S. Toscano; E. Unger; M. Usner; S. Vallecorsa; N. van Eijndhoven; A. Van Overloop; J. van Santen; M. Vehring; M. Voge; M. Vraeghe; C. Walck; T. Waldenmaier; M. Wallraff; Ch. Weaver; M. Wellons; C. Wendt; S. Westerhoff; N. Whitehorn; K. Wiebe; C. H. Wiebusch; D. R. Williams; H. Wissing; M. Wolf; T. R. Wood; K. Woschnagg; D. L. Xu; X. W. Xu; J. P. Yanez; G. Yodh; S. Yoshida; P. Zarzhitsky; J. Ziemann; S. Zierke; M. Zoll

2013-10-21T23:59:59.000Z

277

Azimuthal modulation of cosmic ray flux as an effect of geomagnetic field in the ARGO-YBJ experiment  

E-Print Network (OSTI)

The geomagnetic field causes not only the East-West effect on the primary cosmic rays but also affects the trajectories of the secondary charged particles in the shower, causing their lateral distribution to be stretched along certain directions. Thus both the density of the secondaries near the shower axis and the trigger efficiency of a detector array decrease. The effect depends on the age and on the direction of the showers, thus involving the measured azimuthal distribution. Here the non-uniformity of the azimuthal distribution of the reconstructed events in the ARGO-YBJ experiment is deeply investigated for different zenith angles on the light of this effect. The influence of the geomagnetic field as well as geometric effects are studied by means of a Monte Carlo simulation.

Bernardini, P; He, H H; Mancarella, G; Perrone, L; Surdo, A

2011-01-01T23:59:59.000Z

278

Reconstructing the Cosmic Expansion History up to Redshift z=6.29 with the Calibrated Gamma-Ray Bursts  

E-Print Network (OSTI)

Recently, Gamma-Ray Bursts (GRBs) were proposed to be a complementary cosmological probe to type Ia supernovae (SNIa). GRBs have been advocated to be standard candles since several empirical GRB luminosity relations were proposed as distance indicators. However, there is a so-called circularity problem in the direct use of GRBs. Recently, a new idea to calibrate GRBs in a completely cosmology independent manner has been proposed, and the circularity problem can be solved. In the present work, following the method proposed by Liang {\\it et al.}, we calibrate 70 GRBs with the Amati relation using 307 SNIa. Then, following the method proposed by Shafieloo {\\it et al.}, we smoothly reconstruct the cosmic expansion history up to redshift $z=6.29$ with the calibrated GRBs. We find some new features in the reconstructed results.

Hao Wei; Shuang Nan Zhang

2008-08-18T23:59:59.000Z

279

Evidences of high energy protons with energies beyond 0.4 GeV in the solar particle spectrum as responsible for the cosmic rays solar diurnal anisotropy  

E-Print Network (OSTI)

Analysis on the daily variations of cosmic ray muons with $E_{\\mu}\\geq 0.2 GeV$ based on the data of two directional muon telescopes at sea level and with a rigidity of response to cosmic proton spectrum above 0.4 GV is presented. The analysis covers two months of observations and in 60% of days, abrupt transitions between a low to a high muon intensity and vice-verse is observed, the period of high muon intensity is from $\\sim 8.0h$ up to $\\sim 19.0h$ (local time) and coincides with the period when the interplanetary magnetic field (IMF) lines overtake the Earth. This behavior strongly suggest that the high muon intensity is due to a contribution of solar protons (ions) on the muon intensity produced by the galactic cosmic rays, responsible for the low muon intensity. This implies that the solar particle spectrum extends to energies beyond 1 GeV. We show that this picture can explain the solar daily variation origin, and it is a most accurate scenario than the assumption of corotating galactic cosmic ray with the IMF lines, specially in the high rigidity region. Obtained results are consistent with the data reported in others papers. Some aspects on the sensitivity of our muon telescopes are also presented.

C. E. Navia; C. R. A. Augusto; M. B. Robba; K. H. Tsui

2007-06-26T23:59:59.000Z

280

Evidences of high energy protons with energies beyond 0.4 GeV in the solar particle spectrum as responsible for the cosmic rays solar diurnal anisotropy  

E-Print Network (OSTI)

Analysis on the daily variations of cosmic ray muons with $E_{\\mu}\\geq 0.2 GeV$ based on the data of two directional muon telescopes at sea level and with a rigidity of response to cosmic proton spectrum above 0.4 GV is presented. The analysis covers two months of observations and in 60% of days, abrupt transitions between a low to a high muon intensity and vice-verse is observed, the period of high muon intensity is from $\\sim 8.0h$ up to $\\sim 19.0h$ (local time) and coincides with the period when the interplanetary magnetic field (IMF) lines overtake the Earth. This behavior strongly suggest that the high muon intensity is due to a contribution of solar protons (ions) on the muon intensity produced by the galactic cosmic rays, responsible for the low muon intensity. This implies that the solar particle spectrum extends to energies beyond 1 GeV. We show that this picture can explain the solar daily variation origin, and it is a most accurate scenario than the assumption of corotating galactic cosmic ray wit...

Navia, C E; Robba, M B; Tsui, K H

2007-01-01T23:59:59.000Z

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281

Commissioning of the ATLAS Trigger and Data Acquisition System with Single-Beam and Cosmic Rays  

E-Print Network (OSTI)

ATLAS is one of the two general purpose detectors at the Large Hadron Collider (LHC). It's three-level Trigger and DAQ system (TDAQ) has to investigate a huge rate of events (up to 1 GHz at nominal operating conditions) and retain only the potentially interesting ones (budgeted to ~200 Hz). This paper will give an overview of the system and its innovative features. The early experience on LHC single-beam in 2008 will be shown and then focus on the valuable experience gained in running the DAQ and the trigger reconstruction and event selection in the fast-changing environment of the detector commissioning with cosmic data. Results on system functionality and performance based on preselected simulated events will be also presented. Finally, the readiness of the system for LHC collisions, expected later this year, will be discussed.

Hauser, R; The ATLAS collaboration

2009-01-01T23:59:59.000Z

282

GLAST and Suzaku: Study on Cosmic-Ray Acceleration And Interaction in the Cosmos  

SciTech Connect

The Gamma-Ray Large Area Space Telescope (GLAST) is an international and multiagency mission scheduled for launch in the fall 2007. The Large Area Telescope (LAT), the primary instrument of the mission, will survey the high energy sky found to be very dynamic and surprisingly diverse by its predecessor the Energetic Gamma Ray Experiment Telescope (EGRET). GLAST-LAT will have a much improved sensitivity when compared with EGRET and extend the higher energy coverage to {approx} 300 GeV. The instrument is now mounted on the spacecraft and undergoing a suite of pre-flight tests. Data analysis software has been tried out by collaborators in two rounds of 'Data Challenges' using simulated observations including backgrounds. The instrument performance and observational data on selected sources presented here have been obtained through the Data Challenges in the collaborative efforts. There are features in the GLAST-LAT observation possibly unfamiliar to X-ray astronomers: (1) GLAST will operate mostly in the survey mode; (2) the foreground objects (gas, dust, and star-light) become gamma-ray sources; (3) multiple sources will be 'confused' because of the wide point-spread-function. The last two features will pose a challenge for analysis on extended Galactic sources such as supernova remnants and pulsar wind nebulae: multi-wavelength study with X-ray instruments like Suzaku and atmospheric Chrenkov telescopes will become essential to dig out the underlying physics.

Kamae, T.; /KIPAC, Menlo Park /SLAC

2008-05-23T23:59:59.000Z

283

GEANT4 Simulation of a Cosmic Ray Muon Tomography System with Micro-Pattern Gas Detectors for the Detection of High-Z Materials  

E-Print Network (OSTI)

Muon Tomography (MT) based on the measurement of multiple scattering of atmospheric cosmic ray muons traversing shipping containers is a promising candidate for identifying threatening high-Z materials. Since position-sensitive detectors with high spatial resolution should be particularly suited for tracking muons in an MT application, we propose to use compact micro-pattern gas detectors, such as Gas Electron Multipliers (GEMs), for muon tomography. We present a detailed GEANT4 simulation of a GEM-based MT station for various scenarios of threat material detection. Cosmic ray muon tracks crossing the material are reconstructed with a Point-Of-Closest-Approach algorithm to form 3D tomographic images of the target material. We investigate acceptance, Z-discrimination capability, effects of placement of high-Z material and shielding materials inside the cargo, and detector resolution effects for such a MT station.

Hohlmann, Marcus; Gnanvo, Kondo; Helsby, Jennifer; Pena, David; Hoch, Richard; Mitra, Debasis

2008-01-01T23:59:59.000Z

284

The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory  

Science Conference Proceedings (OSTI)

We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than 60{sup o}, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the {approx} 2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for. In this work, we have identified and quantified a systematic uncertainty affecting the energy determination of cosmic rays detected by the surface detector array of the Pierre Auger Observatory. This systematic uncertainty, induced by the influence of the geomagnetic field on the shower development, has a strength which depends on both the zenith and the azimuthal angles. Consequently, we have shown that it induces distortions of the estimated cosmic ray event rate at a given energy at the percent level in both the azimuthal and the declination distributions, the latter of which mimics an almost dipolar pattern. We have also shown that the induced distortions are already at the level of the statistical uncertainties for a number of events N {approx_equal} 32 000 (we note that the full Auger surface detector array collects about 6500 events per year with energies above 3 EeV). Accounting for these effects is thus essential with regard to the correct interpretation of large scale anisotropy measurements taking explicitly profit from the declination distribution.

Abreu, P.; /Lisbon, IST; Aglietta, M.; /IFSI, Turin; Ahn, E.J.; /Fermilab; Albuquerque, I.F.M.; /Sao Paulo U.; Allard, D.; /APC, Paris; Allekotte, I.; /Centro Atomico Bariloche; Allen, J.; /New York U.; Allison, P.; /Ohio State U.; Alvarez Castillo, J.; /Mexico U., ICN; Alvarez-Muniz, J.; /Santiago de Compostela U.; Ambrosio, M.; /Naples U. /INFN, Naples /Nijmegen U., IMAPP

2011-11-01T23:59:59.000Z

285

The Ulysses Supplement to the BATSE 4Br Catalog of Cosmic Gamma-Ray Bursts  

E-Print Network (OSTI)

We present Interplanetary Network localization information for 147 gammaray bursts observed by the Burst and Transient Source Experiment between the end of the 3rd BATSE catalog and the end of the 4th BATSE catalog, obtained by analyzing the arrival times of these bursts at the Ulysses and Compton Gamma-Ray Observatory (CGRO) spacecraft. For any given burst observed by these two spacecraft, arrival time analysis (or “triangulation”) results in an annulus of possible arrival directions whose half-width varies between 7 arcseconds and 2.3 degrees, depending on the intensity and time history of the burst, and the distance of the Ulysses spacecraft from Earth. This annulus generally intersects the BATSE error circle, resulting in an average reduction of the error box area of a factor of 25. Subject headings: gamma-rays: bursts; catalogs 1

K. Hurley; M. S. Briggs; C. Kouveliotou; C. Meegan; G. Fishman; T. Cline

1998-01-01T23:59:59.000Z

286

CONSTRAINTS ON COSMIC RAYS, MAGNETIC FIELDS, AND DARK MATTER FROM GAMMA-RAY OBSERVATIONS OF THE COMA CLUSTER OF GALAXIES WITH VERITAS AND FERMI  

SciTech Connect

Observations of radio halos and relics in galaxy clusters indicate efficient electron acceleration. Protons should likewise be accelerated and, on account of weak energy losses, can accumulate, suggesting that clusters may also be sources of very high energy (VHE; E > 100 GeV) gamma-ray emission. We report here on VHE gamma-ray observations of the Coma galaxy cluster with the VERITAS array of imaging Cerenkov telescopes, with complementing Fermi Large Area Telescope observations at GeV energies. No significant gamma-ray emission from the Coma Cluster was detected. Integral flux upper limits at the 99% confidence level were measured to be on the order of (2-5) Multiplication-Sign 10{sup -8} photons m {sup -2} s {sup -1} (VERITAS, >220 GeV) and {approx}2 Multiplication-Sign 10{sup -6} photons m {sup -2} s {sup -1} (Fermi, 1-3 GeV), respectively. We use the gamma-ray upper limits to constrain cosmic rays (CRs) and magnetic fields in Coma. Using an analytical approach, the CR-to-thermal pressure ratio is constrained to be <16% from VERITAS data and <1.7% from Fermi data (averaged within the virial radius). These upper limits are starting to constrain the CR physics in self-consistent cosmological cluster simulations and cap the maximum CR acceleration efficiency at structure formation shocks to be <50%. Alternatively, this may argue for non-negligible CR transport processes such as CR streaming and diffusion into the outer cluster regions. Assuming that the radio-emitting electrons of the Coma halo result from hadronic CR interactions, the observations imply a lower limit on the central magnetic field in Coma of {approx}(2-5.5) {mu}G, depending on the radial magnetic field profile and on the gamma-ray spectral index. Since these values are below those inferred by Faraday rotation measurements in Coma (for most of the parameter space), this renders the hadronic model a very plausible explanation of the Coma radio halo. Finally, since galaxy clusters are dark matter (DM) dominated, the VERITAS upper limits have been used to place constraints on the thermally averaged product of the total self-annihilation cross section and the relative velocity of the DM particles, ({sigma}v).

Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Byrum, K. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Cannon, A.; Collins-Hughes, E. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W.; Feng, Q.; Finley, J. P. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Dumm, J. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Falcone, A. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Federici, S., E-mail: pohlmadq@gmail.com, E-mail: christoph.pfrommer@h-its.org [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); and others

2012-10-01T23:59:59.000Z

287

The Lateral Trigger Probability function for the Ultra-High Energy Cosmic Ray Showers detected by the Pierre Auger Observatory  

E-Print Network (OSTI)

In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an extensive air shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface array of the Pierre Auger Observatory consisting of a 1.5 km spaced grid of about 1600 water Cherenkov stations. Using Monte Carlo simulations of ultra-high energy showers the LTP functions are derived for energies in the range between 10^{17} and 10^{19} eV and zenith angles up to 65 degs. A parametrization combining a step function with an exponential is found to reproduce them very well in the considered range of energies and zenith angles. The LTP functions can also be obtained from data using events simultaneously observed by the fluorescence and the surface detector of the Pierre Auger Observatory (hybrid events). We validate the Monte-Carlo results showing how LTP functions from data are in good agreement with simulations.

The Pierre Auger Collaboration; P. Abreu; M. Aglietta; E. J. Ahn; I. F. M. Albuquerque; D. Allard; I. Allekotte; J. Allen; P. Allison; J. Alvarez Castillo; J. Alvarez-Muñiz; M. Ambrosio; A. Aminaei; L. Anchordoqui; S. Andringa; T. Anti?i?; A. Anzalone; C. Aramo; E. Arganda; F. Arqueros; H. Asorey; P. Assis; J. Aublin; M. Ave; M. Avenier; G. Avila; T. Bäcker; M. Balzer; K. B. Barber; A. F. Barbosa; R. Bardenet; S. L. C. Barroso; B. Baughman; J. Bäuml; J. J. Beatty; B. R. Becker; K. H. Becker; A. Bellétoile; J. A. Bellido; S. BenZvi; C. Berat; X. Bertou; P. L. Biermann; P. Billoir; F. Blanco; M. Blanco; C. Bleve; H. Blümer; M. Bohá?ová; D. Boncioli; C. Bonifazi; R. Bonino; N. Borodai; J. Brack; P. Brogueira; W. C. Brown; R. Bruijn; P. Buchholz; A. Bueno; R. E. Burton; K. S. Caballero-Mora; L. Caramete; R. Caruso; A. Castellina; O. Catalano; G. Cataldi; L. Cazon; R. Cester; J. Chauvin; S. H. Cheng; A. Chiavassa; J. A. Chinellato; A. Chou; J. Chudoba; R. W. Clay; M. R. Coluccia; R. Conceição; F. Contreras; H. Cook; M. J. Cooper; J. Coppens; A. Cordier; S. Coutu; C. E. Covault; A. Creusot; A. Criss; J. Cronin; A. Curutiu; S. Dagoret-Campagne; R. Dallier; S. Dasso; K. Daumiller; B. R. Dawson; R. M. de Almeida; M. De Domenico; C. De Donato; S. J. de Jong; G. De La Vega; W. J. M. de Mello Junior; J. R. T. de Mello Neto; I. De Mitri; V. de Souza; K. D. de Vries; G. Decerprit; L. del Peral; M. del Río; O. Deligny; H. Dembinski; N. Dhital; C. Di Giulio; J. C. Diaz; M. L. Díaz Castro; P. N. Diep; C. Dobrigkeit; W. Docters; J. C. D'Olivo; P. N. Dong; A. Dorofeev; J. C. dos Anjos; M. T. Dova; D. D'Urso; I. Dutan; J. Ebr; R. Engel; M. Erdmann; C. O. Escobar; J. Espadanal; A. Etchegoyen; P. Facal San Luis; I. Fajardo Tapia; H. Falcke; G. Farrar; A. C. Fauth; N. Fazzini; A. P. Ferguson; A. Ferrero; B. Fick; A. Filevich; A. Filip?i?; S. Fliescher; C. E. Fracchiolla; E. D. Fraenkel; U. Fröhlich; B. Fuchs; R. Gaior; R. F. Gamarra; S. Gambetta; B. García; D. García Gámez; D. Garcia-Pinto; A. Gascon; H. Gemmeke; K. Gesterling; P. L. Ghia; U. Giaccari; M. Giller; H. Glass; M. S. Gold; G. Golup; F. Gomez Albarracin; M. Gómez Berisso; P. Gonçalves; D. Gonzalez; J. G. Gonzalez; B. Gookin; D. Góra; A. Gorgi; P. Gouffon; S. R. Gozzini; E. Grashorn; S. Grebe; N. Griffith; M. Grigat; A. F. Grillo; Y. Guardincerri; F. Guarino; G. P. Guedes; A. Guzman; J. D. Hague; P. Hansen; D. Harari; S. Harmsma; J. L. Harton; A. Haungs; T. Hebbeker; D. Heck; A. E. Herve; C. Hojvat; N. Hollon; V. C. Holmes; P. Homola; J. R. Hörandel; A. Horneffer; M. Hrabovský; T. Huege; A. Insolia; F. Ionita; A. Italiano; C. Jarne; S. Jiraskova; M. Josebachuili; K. Kadija; K. H. Kampert; P. Karhan; P. Kasper; B. Kégl; B. Keilhauer; A. Keivani; J. L. Kelley; E. Kemp; R. M. Kieckhafer; H. O. Klages; M. Kleifges; J. Kleinfeller; J. Knapp; D. -H. Koang; K. Kotera; N. Krohm; O. Krömer; D. Kruppke-Hansen; F. Kuehn; D. Kuempel; J. K. Kulbartz; N. Kunka; G. La Rosa; C. Lachaud; P. Lautridou; M. S. A. B. Leão; D. Lebrun; P. Lebrun; M. A. Leigui de Oliveira; A. Lemiere; A. Letessier-Selvon; I. Lhenry-Yvon; K. Link; R. López; A. Lopez Agüera; K. Louedec; J. Lozano Bahilo; L. Lu; A. Lucero; M. Ludwig; H. Lyberis; M. C. Maccarone; C. Macolino; S. Maldera; D. Mandat; P. Mantsch; A. G. Mariazzi; J. Marin; V. Marin; I. C. Maris; H. R. Marquez Falcon; G. Marsella; D. Martello; L. Martin; H. Martinez; O. Martínez Bravo; H. J. Mathes; J. Matthews; J. A. J. Matthews; G. Matthiae; D. Maurizio; P. O. Mazur; G. Medina-Tanco; M. Melissas; D. Melo; E. Menichetti; A. Menshikov; P. Mertsch; C. Meurer; S. Mi?anovi?; M. I. Micheletti; W. Miller; L. Miramonti; L. Molina-Bueno; S. Mollerach; M. Monasor; D. Monnier Ragaigne; F. Montanet; B. Morales; C. Morello; E. Moreno; J. C. Moreno; C. Morris; M. Mostafá; C. A. Moura; S. Mueller; M. A. Muller; G. Müller; M. Münchmeyer; R. Mussa; G. Navarra ‡; J. L. Navarro; S. Navas; P. Necesal; L. Nellen; A. Nelles; J. Neuser; P. T. Nhung; L. Niemietz; N. Nierstenhoefer; D. Nitz; D. Nosek; L. Nožka; M. Nyklicek; J. Oehlschläger; A. Olinto; P. Oliva; V. M. Olmos-Gilbaja; M. Ortiz; N. Pacheco; D. Pakk Selmi-Dei; M. Palatka; J. Pallotta; N. Palmieri; G. Parente; E. Parizot; A. Parra; R. D. Parsons; S. Pastor; T. Paul; M. Pech; J. P?kala; R. Pelayo; I. M. Pepe; L. Perrone; R. Pesce; E. Petermann; S. Petrera; P. Petrinca; A. Petrolini; Y. Petrov; J. Petrovic; C. Pfendner; N. Phan; R. Piegaia; T. Pierog; P. Pieroni; M. Pimenta; V. Pirronello; M. Platino; V. H. Ponce; M. Pontz; P. Privitera; M. Prouza; E. J. Quel; S. Querchfeld; J. Rautenberg; O. Ravel; D. Ravignani; B. Revenu; J. Ridky; S. Riggi; M. Risse; P. Ristori; H. Rivera; V. Rizi; J. Roberts; C. Robledo; W. Rodrigues de Carvalho; G. Rodriguez; J. Rodriguez Martino; J. Rodriguez Rojo

2011-11-28T23:59:59.000Z

288

THE ROLE OF STRUCTURED MAGNETIC FIELDS ON CONSTRAINING PROPERTIES OF TRANSIENT SOURCES OF ULTRA-HIGH-ENERGY COSMIC RAYS  

SciTech Connect

We study how the properties of transient sources of ultra-high-energy cosmic rays (UHECRs) can be accessed by exploiting UHECR experiments, taking into account the propagation of UHECRs in magnetic structures which the sources are embedded in, i.e., clusters of galaxies and filamentary structures. Adopting simplified analytical models, we demonstrate that the structured extragalactic magnetic fields (EGMFs) play crucial roles in unveiling the properties of the transient sources. These EGMFs unavoidably cause significant delay in the arrival time of UHECRs as well as the Galactic magnetic field, even if the strength of magnetic fields in voids is zero. Then, we show that, given good knowledge on the structured EGMFs, UHECR observations with high statistics above 10{sup 20} eV allow us to constrain the generation rate of transient UHECR sources and their energy input per burst, which can be compared with the rates and energy release of known astrophysical phenomena. We also demonstrate that identifying the energy dependence of the apparent number density of UHECR sources at the highest energies is crucial to such transient sources. Future UHECR experiments with extremely large exposure are required to reveal the nature of transient UHECR sources.

Takami, Hajime [Max Planck Institute for Physics, Foehringer Ring 6, 80805 Munich (Germany); Murase, Kohta, E-mail: takami@mpp.mpg.de [Center for Cosmology and AstroParticle Physics, The Ohio State University, 191 W. Woodruff Ave., Columbus, OH 43210 (United States)

2012-03-20T23:59:59.000Z

289

A Detailed Study of FDIRC Prototype with Waveform Digitizing Electronics in Cosmic Ray Telescope Using 3D Tracks  

SciTech Connect

We present a detailed study of a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. In this test study, the FDIRC prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from {approx}450 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of {approx}2.5 GSa/s. The FDIRC prototype was tested in a large cosmic ray telescope (CRT) providing 3D muon tracks with {approx}1.5 mrad angular resolution and muon energy of E{sub muon} > 1.6 GeV. In this study we provide a detailed analysis of the tails in the Cherenkov angle distribution as a function of various variables, compare experimental results with simulation, and identify the major contributions to the tails. We demonstrate that to see the full impact of these tails on the Cherenkov angle resolution, it is crucial to use 3D tracks, and have a full understanding of the role of ambiguities. These issues could not be fully explored in previous FDIRC studies where the beam was perpendicular to the quartz radiator bars. This work is relevant for the final FDIRC prototype of the PID detector at SuperB, which will be tested this year in the CRT setup.

Nishimura, K.; Dey, B.; /Hawaii U. /UC, Riverside; Aston, D.; Leith, D.W.G.S.; Ratcliff, B.; /SLAC; Roberts, D.; /Maryland U.; Ruckman, L.; /Hawaii U.; Shtol, D.; /Novosibirsk, IYF; Varner, G.S.; /Hawaii U.; Va'vra, J.; Vavra, Jerry; /SLAC

2012-07-30T23:59:59.000Z

290

New Physics at the Tevatron and the LHC May Relate to Dark Matter Visible in UHE Cosmic Rays  

E-Print Network (OSTI)

A two flavor color sextet quark sector added to QCD yields the {\\it uniquely} unitary Critical Pomeron at high energy while also producing electroweak symmetry breaking. In this paper it is argued that a number of experimental phenomena in Cosmic Ray and hadron collider physics can be interpreted as evidence for the sextet sector. These phenomena include (1) Top quark production is via the eta_6 sextet quark pseudoscalar resonance - interference with the background will produce an asymmetry. (2) Longitudinal Z pairs, produced as sextet pions, provide a high mass excess cross-section that includes the eta_6 at the t-tbar threshold mass. Combining the sextet sector and the electroweak interaction without short-distance anomalies requires QUD - a unique underlying weak coupling massless SU(5) gauge theory. Remarkably, it appears that the Standard Model might be reproduced (in a radical conceptual change) by the QUD bound-state S-Matrix. Infra-red divergent gauge bosons coupled to massless fermion anomalies produce a "wee parton vacuum" that confines the elementary fermions. All S-Matrix particles have dynamically generated masses, with sextet baryons as the only new particles - beyond the Standard Model. Anomaly color factors produce large sextet amplitudes and there is no Higgs boson.

Alan. R. White

2011-06-28T23:59:59.000Z

291

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE FERMI GBM CATALOG OF COSMIC GAMMA-RAY BURSTS  

Science Conference Proceedings (OSTI)

We present Interplanetary Network (IPN) data for the gamma-ray bursts in the first Fermi Gamma-Ray Burst Monitor (GBM) catalog. Of the 491 bursts in that catalog, covering 2008 July 12 to 2010 July 11, 427 were observed by at least one other instrument in the nine-spacecraft IPN. Of the 427, the localizations of 149 could be improved by arrival time analysis (or {sup t}riangulation{sup )}. For any given burst observed by the GBM and one other distant spacecraft, triangulation gives an annulus of possible arrival directions whose half-width varies between about 0.'4 and 32 Degree-Sign , depending on the intensity, time history, and arrival direction of the burst, as well as the distance between the spacecraft. We find that the IPN localizations intersect the 1{sigma} GBM error circles in only 52% of the cases, if no systematic uncertainty is assumed for the latter. If a 6 Degree-Sign systematic uncertainty is assumed and added in quadrature, the two localization samples agree about 87% of the time, as would be expected. If we then multiply the resulting error radii by a factor of three, the two samples agree in slightly over 98% of the cases, providing a good estimate of the GBM 3{sigma} error radius. The IPN 3{sigma} error boxes have areas between about 1 arcmin{sup 2} and 110 deg{sup 2}, and are, on the average, a factor of 180 smaller than the corresponding GBM localizations. We identify two bursts in the IPN/GBM sample that did not appear in the GBM catalog. In one case, the GBM triggered on a terrestrial gamma flash, and in the other, its origin was given as ''uncertain''. We also discuss the sensitivity and calibration of the IPN.

Hurley, K. [University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Pal'shin, V. D.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Mazets, E. P.; Svinkin, D. S. [Ioffe Physical Technical Institute, St. Petersburg 194021 (Russian Federation); Briggs, M. S.; Connaughton, V. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Meegan, C. [Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Goldsten, J. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Boynton, W.; Fellows, C.; Harshman, K. [University of Arizona, Department of Planetary Sciences, Tucson, AZ 85721 (United States); Mitrofanov, I. G.; Golovin, D. V.; Kozyrev, A. S.; Litvak, M. L.; Sanin, A. B. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Rau, A., E-mail: khurley@ssl.berkeley.edu [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); and others

2013-08-15T23:59:59.000Z

292

A Model for Most Luminous and Long Duration Cosmic Gamma Ray Bursts  

E-Print Network (OSTI)

We exploit the fact that General Theory of Relativity (GTR) predicts the existence of compact objects having surface gravitational redshift z_s burst rises dramatically with the value of z_c and can saturate to ~40%. This may explain a gamma ray burst of energy as high as ~5. 10**53 erg. By using the already existing detailed (Newtonian) calculations, it follows that the neutrino heating driven mass loss should be negligible, and the bulk Lorentz factor of the initial fireball could be ~1000. Most of the existing supernova calculations also show that it is extremely difficult to simulate the direct neutrino driven mass loss, and, the shock is not launched if the gravitational field becomes stronger. Since the gravitation potential well of the more compact NS is indded very deep, we do not expect additional baryonic mass ejection. So, without invoking any exotic physics (like strange stars) or overstretching any theory, we may explain most of the luminous GRBs in this simple model.

Abhas Mitra

1998-12-03T23:59:59.000Z

293

A study of the shadowing of galactic cosmic rays by the sun in a quiet phase of solar activity with the Tibet air shower array  

E-Print Network (OSTI)

We have shown that the Sun's shadow by high energy cosmic rays moves year by year and its behavior is correlated with a time variation of the large-scale structure of the solar and interplanetary magnetic fields. The solar activity was near minimum in the period from 1996 through 1997. Using the data obtained with the Tibet air shower array, we examined the shadowing of cosmic rays by the Sun in this quiet phase of solar cycle, and found that the Sun's shadow was just in the apparent direction of the Sun, though it was observed at the position considerably away from the Sun to the south-west in the period between 1990 and 1993. It is known that the magnetic pole of equivalent solar dipole was reversed during the previous active phase, and near solar minimum the dipole was aligned with the rotating axis, preserving its N-pole on the north pole side of the Sun. This causes the solar magnetic field to shift the Sun's shadow to the east. Thus, the observed results suggest that the shift of the Sun's shadow due to the solar magnetic field was pushed back by the effect of the geomagnetic field, since the geomagnetic field always make the shadow shift to the west. We discuss the Sun's shadow observed during the period near solar minimum in 1996-1997 and compare it with the simulation results.

M. Amenomori; S. Ayabe; Caidong

2000-08-10T23:59:59.000Z

294

The IceCube Collaboration:contributions to the 30 th International Cosmic Ray Conference (ICRC 2007),  

E-Print Network (OSTI)

variety of sources (gamma-ray bursts, active galac- ticgalactic nuclei or gamma-ray bursts [1, 2]. Instead ofnuclei (AGN) and gamma-ray bursts (GRB) are potential

Ackermann, M.; IceCube Collaboration

2008-01-01T23:59:59.000Z

295

Registration of the signal of a star and PCR sources optical radiation by means of the installation, aimed at the investigation of EAS of high energy cosmic rays  

E-Print Network (OSTI)

With the help of the experimental installation aimed at the investigation of high energy cosmic rays (Tien-Shan high mountain laboratory) the signal of Solar and star optical radiation is registered. The signal is well provided statistically and possesses the strictly expressed maximum in the region of EAS sizes Ne 1.19 106 particles (primary energy Eo 1.33 1015 eV). This signal is the peak from gamma EAS, generated by gamma quanta from decay of pi zero mesons, photo produced by the Primary Cosmic Radiation (PCR) nuclei on the photons of stars and of PCR sources. The assumption is made, that exactly this process provides the main contribution in the formation of so called knee on the primary spectrum. Due to the universality and distinct maximum of this signal, its usage for independent and reliable calibration of the EAS installations, for the mutual calibration of these installations and, possibly, for the merger of experimental data obtained by means of these installations to increase the statistics, is pr...

Barnaveli, T T; Khaldeeva, I V; Chubenko, A P; Nesterova, N M; Barnaveli, T T

2013-01-01T23:59:59.000Z

296

First Result from the Alpha Magnetic Spectrometer on the International Space Station: Precision Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5–350 GeV  

E-Print Network (OSTI)

A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8×10[superscript 6] positron ...

Basil, A.

297

International scientific cooperation during the 1930s. Bruno Rossi and the development of the status of cosmic rays into a branch of physics  

E-Print Network (OSTI)

During the 1920s and 1930s strong relationships established between Italy and other European countries such as Germany, Great Britain and France, as well as with some physicists of the U.S. scientific community. Bruno Rossi, a leading personality in the study of cosmic rays and the pioneer of this research field in Italy since the early 1930s, is a prominent example in this sense. During those turbulent years in European history, when physics underwent major changes and the traditional internationalism of physics assumed a more institutionalised character, his early work was crucial in transforming the field in a branch of modern physics. His friendly relationship with eminent scientists -notably Enrico Fermi, Walther Bothe, Werner Heisenberg, Hans Bethe, Homi Bhabha- was instrumental for the exchange of knowledge about experimental practises and for theoretical discussions, as well as in attracting the attention of physicists such as Arthur Compton, Louis Leprince-Ringuet, Pierre Auger and Patrick Blackett o...

Bonolis, Luisa

2013-01-01T23:59:59.000Z

298

On the possibility to discriminate the mass of the primary cosmic ray using the muon arrival times from extensive air showers: Application for Pierre Auger Observatory  

SciTech Connect

In this paper we study the possibility to discriminate the mass of the primary cosmic ray by observing the muon arrival times in ground detectors. We analyzed extensive air showers (EAS) induced by proton and iron nuclei with the same energy 8 Multiplication-Sign 10{sup 17} eV simulated with CORSIKA, and analyzed the muon arrival times at ground measured by the infill array detectors of the Pierre Auger Observatory (PAO). From the arrival times of the core and of the muons the atmospheric depth of muon generation locus is evaluated. The results suggest a potential mass discrimination on the basis of muon arrival times and of the reconstructed atmospheric depth of muon production. An analysis of a larger set of CORSIKA simulations carried out for primary energies above 10{sup 18} eV is in progress.

Arsene, N.; Rebel, H.; Sima, O. [Institute of Space Science (ISS), Bucharest-Magurele, P.O. Box MG-23 (Romania) and Physics Department, University of Bucharest, Bucharest-Magurele (Romania); Karlsruhe Institute of Technology, Karlsruhe (Germany); Physics Department, University of Bucharest, Bucharest-Magurele (Romania)

2012-11-20T23:59:59.000Z

299

Measurement of the Cosmic-Ray Antiproton to Proton Abundance Ratio between 4 and 50 GeV  

E-Print Network (OSTI)

We present a new measurement of the antiproton to proton abundance ratio, pbar/p, in the cosmic radiation. The HEAT-pbar instrument, a balloon borne magnet spectrometer with precise rigidity and multiple energy loss measurement capability, was flown successfully in Spring 2000, at an average atmospheric depth of 7.2 g/cm^2. A total of 71 antiprotons were identified above the vertical geomagnetic cut-off rigidity of 4.2 GV. The highest measured proton energy was 81 GeV. We find that the pbar/p abundance ratio agrees with that expected from a purely secondary origin of antiprotons produced by primary protons with a standard soft energy spectrum.

A. S. Beach; J. J. Beatty; A. Bhattacharyya; C. Bower; S. Coutu; M. A. DuVernois; A. W. Labrador; S. McKee; S. A. Minnick; D. Muller; J. Musser; S. Nutter; M. Schubnell; S. Swordy; G. Tarle; A. Tomasch

2001-11-05T23:59:59.000Z

300

THE SEARCH FOR POSSIBLE MESOLENSING OF COSMIC GAMMA-RAY BURSTS. DOUBLE AND TRIPLE BURSTS IN BATSE CATALOGUE  

E-Print Network (OSTI)

The work is devoted to the search for possible effect of gravitational lensing on the objects like globular stellar clusters (mesolensing) on the lightcurves and spectra of large number of gamma-ray bursts from BATSE catalogue. The general properties and different types of such event were considered. As the result 11 possibly mesolensed gamma-ray bursts were found. The propeties of possible mesolenses are invesigated. 1

O. S. Ougolnikov

2001-01-01T23:59:59.000Z

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301

SOLAR CYCLE DEPENDENCE OF THE DIURNAL ANISOTROPY OF 0.6 TeV COSMIC-RAY INTENSITY OBSERVED WITH THE MATSUSHIRO UNDERGROUND MUON DETECTOR  

SciTech Connect

We analyze the temporal variation of the diurnal anisotropy of sub-TeV cosmic-ray intensity observed with the Matsushiro (Japan) underground muon detector over two full solar activity cycles in 1985-2008. We find an anisotropy component in the solar diurnal anisotropy superimposed on the Compton-Getting anisotropy due to Earth's orbital motion around the Sun. The phase of this additional anisotropy is almost constant at {approx}15:00 local solar time corresponding to the direction perpendicular to the average interplanetary magnetic field at Earth's orbit, while the amplitude varies between a maximum (0.043% +- 0.002%) and minimum ({approx}0.008% +- 0.002%) in a clear correlation with the solar activity. We find a significant time lag between the temporal variations of the amplitude and the sunspot number (SSN) and obtain the best correlation coefficient of +0.74 with the SSN delayed for 26 months. We suggest that this anisotropy might be interpreted in terms of the energy change due to the solar-wind-induced electric field expected for galactic cosmic rays (GCRs) crossing the wavy neutral sheet. The average amplitude of the sidereal diurnal variation over the entire period is 0.034% +- 0.003%, which is roughly one-third of the amplitude reported from air shower and deep-underground muon experiments monitoring multi-TeV GCR intensity suggesting a significant attenuation of the anisotropy due to the solar modulation. We find, on the other hand, only a weak positive correlation between the sidereal diurnal anisotropy and the solar activity cycle in which the amplitude in the 'active' solar activity epoch is about twice the amplitude in the 'quiet' solar activity epoch. This implies that only one-fourth of the total attenuation varies in correlation with the solar activity cycle and/or the solar magnetic cycle. We finally examine the temporal variation of the 'single-band valley depth' (SBVD) quoted by the Milagro experiment and, in contrast with recent Milagro's report, we find no steady increase in the Matsushiro observations in a seven-year period between 2000 and 2007. We suggest, therefore, that the steady increase of the SBVD reported by the Milagro experiment is not caused by the decreasing solar modulation in the declining phase of the 23rd solar activity cycle.

Munakata, K.; Mizoguchi, Y.; Kato, C.; Yasue, S.; Mori, S. [Department of Physics, Shinshu University, Matsumoto 390-8621 (Japan); Takita, M. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan); Kota, J., E-mail: kmuna00@shinshu-u.ac.j [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 87721 (United States)

2010-04-01T23:59:59.000Z

302

Mass composition of 10{sup 17}- to 10{sup 18}-eV primary cosmic rays according to data on the lateral distribution of radio emission from extensive air showers  

SciTech Connect

Experimental data obtained for the lateral distribution of radio emission from extensive air showers (EAS) at the array of Moscow State University (30-34 MHz) and the LOPES array (40-80 MHz) were comparedwith the results of calculations performed within amicroscopic approach based on aMonte Carlo simulation of EAS (CORSIKA code). The same experimental data were used to reconstruct the distribution of the depth of the EAS maximum at cosmic-ray energies in the range of 1017-1018 eV. The energy dependence of the depth of the EAS maximum was constructed for the case of data from the LOPES array, and the mass composition of cosmic rays was estimated for this case. From the resulting dependences, it follows that the mass composition shows a trend toward becoming lighter in the energy range being considered.

Kalmykov, N. N., E-mail: kalm@eas.sinp.msu.ru; Konstantinov, A. A.; Vedeneev, O. V. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2012-12-15T23:59:59.000Z

303

Cosmic Parallax  

E-Print Network (OSTI)

Future satellite missions such as GAIA will achieve astrometry measurements with an accuracy of about 10 $\\mu$as for bright sources; other satellite proposals aim at 1 $\\mu$as. We show in this paper that such refined measurements allow us to detect large-scale deviations from isotropy through real-time observations of changes in the angular separation between sources at cosmic distances. We show that this "cosmic parallax'' effect is a powerful consistency test of Friedmann-Robertson-Walker metric and may set very strong constraints on alternative anisotropic models like Lemaitre-Tolman-Bondi cosmologies with off-center observers.

Quercellini, Claudia; Amendola, Luca

2008-01-01T23:59:59.000Z

304

Do the environmental conditions affect the dust-induced fragmentation in low-metallicity clouds ?: Effect of pre-ionization and far-ultraviolet/cosmic-ray fields  

E-Print Network (OSTI)

We study effects of the fully ionized initial state, or pre-ionization, on the subsequent thermal evolution of low-metallicity clouds under various intensities of the external far-ultraviolet(FUV) and cosmic-ray(CR) fields. The pre-ionization significantly affects the thermal and dynamical evolution of metal-free clouds without FUV/CRs by way of efficient HD formation. On the other hand, the pre-ionization effect on the thermal evolution is limited in very low-density regime for more metal-enriched clouds ([Z/H] >~ -4) or those under modest FUV (>10^{-3}) or CR field (>0.1 of the present-day Galactic disk levels). In any case, for >10^8 cm^{-3}, neither the initial ionization state nor the irradiating FUV strength affect the thermal evolution. The dust cooling is an important mechanism for making sub-solar mass fragments in low-metallicity gas. Since this fragmentation occurs at the temperature minimum by the dust cooling at >10^{10} cm^{-3}, this process is not vulnerable either to initial ionization state o...

Omukai, Kazuyuki

2012-01-01T23:59:59.000Z

305

GEANT4 Simulation of a Scintillating-Fibre Tracker for the Cosmic-ray Muon Tomography of Legacy Nuclear Waste Containers  

E-Print Network (OSTI)

Cosmic-ray muons are highly penetrative charged particles that are observed at sea level with a flux of approximately one per square centimetre per minute. They interact with matter primarily through Coulomb scattering, which is exploited in the field of muon tomography to image shielded objects in a wide range of applications. In this paper, simulation studies are presented that assess the feasibility of a scintillating-fibre tracker system for use in the identification and characterisation of nuclear materials stored within industrial legacy waste containers. A system consisting of a pair of tracking modules above and a pair below the volume to be assayed is simulated within the GEANT4 framework using a range of potential fibre pitches and module separations. Each module comprises two orthogonal planes of fibres that allow the reconstruction of the initial and Coulomb-scattered muon trajectories. A likelihood-based image reconstruction algorithm has been developed that allows the container content to be determined with respect to the atomic number Z of the scattering material. Images reconstructed from this simulation are presented for a range of anticipated scenarios that highlight the expected image resolution and the potential of this system for the identification of high-Z materials within a shielded, concrete-filled container. First results from a constructed prototype system are presented in comparison with those from a detailed simulation. Excellent agreement between experimental data and simulation is observed showing clear discrimination between the different materials assayed throughout.

Anthony Clarkson; David J. Hamilton; Matthias Hoek; David G. Ireland; Russell Johnstone; Ralf Kaiser; Tibor Keri; Scott Lumsden; David F. Mahon; Bryan McKinnon; Morgan Murray; Sian Nutbeam-Tuffs; Craig Shearer; Cassie Staines; Guangliang Yang; Colin Zimmerman

2013-09-13T23:59:59.000Z

306

6th ANL/MSU/JINA/INT FRIB Theory Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Home Participants Program & Talks Location Access Lodging Transportation Restaurants Forms 6th ANL/MSU/JINA/INT FRIB Theory Workshop Computational Forefront in Nuclear Theory: Preparing for FRIB Argonne National Laboratory, March 23 - 26, 2010 This workshop will concentrate on advances in theoretical methods for computing properties of nuclei and reactions relevant to the experimental program at FRIB. Although we expect a significant number of talks on methods that require the largest available and planned computers, there will also be talks on new methods that do not require such large machines. Topics quantum Monte Carlo -- no-core shell model -- coupled-cluster method -- unitary correlated-operator method -- shell model -- continuum shell model -- Gamow shell model -- energy density functionals -- cranking -- heavy-ion

307

NERSC Helps Discover Cosmic Transients - NERSC Science News June...  

NLE Websites -- All DOE Office Websites (Extended Search)

Lab) to expose relatively rare and fleeting cosmic events, like supernovae and gamma ray bursts. In fact, during the commissioning phase alone, the survey has already uncovered...

308

The Ulysses Catalog of Solar Hard X-Ray Flares  

E-Print Network (OSTI)

its Solar X-ray/Cosmic Gamma-Ray Burst Experiment (GRB) hasInstrument The Ulysses Gamma-Ray Burst (GRB) instrument, hasrate due to a cosmic gamma-ray burst or a solar ?are, but we

Tranquille, C.; Hurley, K.; Hudson, H. S.

2009-01-01T23:59:59.000Z

309

Approximation of lateral distribution of atmospheric Cherenkov light at different observation levels for different primary particles. Applications for cosmic ray studies  

E-Print Network (OSTI)

This work summarizes the results presented at 29th International Cosmic Ray Conference in Pune India. Generally the aim of this work is to obtain the lateral distribution of the atmospheric Cherenkov light in extensive air showers produced by different primary particles in wide energy range and at several observation levels and to fit the obtained lateral distributions. Using one large detector and partially modified CORSIKA code version are obtained the lateral distributions of Cherenkov light flux densities at several observation levels for different particle primaries precisely at 536 g/cm2 Chacaltaya, 700 g/cm2 Moussala and 875 g/cm2 Kartalska field observation levels for hadronic primaries and gamma quanta in the energy range 1011 eV-1016 eV. On the basis of the solution of over-determined inverse problem the approximation of these distributions is obtained. The same model function for all the primaries is used and for the different observation levels. The different model parameters for the different primaries and levels are obtained. The approximations are compared with polynomial approximation obtained with different method. Both approximations are used for detector efficiency estimation for the different experiments in preparation and estimation of the accuracy of the reconstruction techniques. At the same time inclined showers up to 30 degrees zenith angle are studied at Chacaltaya observation level. The obtained lateral distributions of vertical showers are compared with vertical showers model and the previously obtained approximation. This permits to adjust the reconstruction strategy and to study the model parameters behavior.

Alexander Mishev; Strashimir Mavrodiev; Jordan Stamenov

2005-11-29T23:59:59.000Z

310

2Cosmic Bar Graphs Galaxy Type  

E-Print Network (OSTI)

or cosmic gamma ray bursts by other instruments in the IPN. It has also observed over 130 events which review the highlights of these observations, which include gamma-ray bursts, soft gamma repeaters Name 1.Introduction The SPI anticoincidence system was first proposed as a gamma-ray burst (GRB

311

Materials for Nuclear Power: Digital Resource Center - 15th Int'l ...  

Science Conference Proceedings (OSTI)

Apr 14, 2011... Trends in Nuclear Power, The Nuclear Fuel Cycle, Nuclear Science ... 15th Int'l Conference on Environmental Degradation in Nuclear Power ...

312

INITIAL DATA RELEASE OF THE KEPLER-INT SURVEY  

Science Conference Proceedings (OSTI)

This paper describes the first data release of the Kepler-INT Survey (KIS) that covers a 116 deg{sup 2} region of the Cygnus and Lyra constellations. The Kepler field is the target of the most intensive search for transiting planets to date. Despite the fact that the Kepler mission provides superior time-series photometry, with an enormous impact on all areas of stellar variability, its field lacks optical photometry complete to the confusion limit of the Kepler instrument necessary for selecting various classes of targets. For this reason, we follow the observing strategy and data reduction method used in the IPHAS and UVEX galactic plane surveys in order to produce a deep optical survey of the Kepler field. This initial release concerns data taken between 2011 May and August, using the Isaac Newton Telescope on the island of La Palma. Four broadband filters were used, U, g, r, i, as well as one narrowband one, H{alpha}, reaching down to a 10{sigma} limit of {approx}20th mag in the Vega system. Observations covering {approx}50 deg{sup 2}, thus about half of the field, passed our quality control thresholds and constitute this first data release. We derive a global photometric calibration by placing the KIS magnitudes as close as possible to the Kepler Input Catalog (KIC) photometry. The initial data release catalog containing around 6 million sources from all the good photometric fields is available for download from the KIS Web site (www.astro.warwick.ac.uk/research/kis/) as well as via MAST (KIS magnitudes can be retrieved using the MAST enhanced target search page http://archive.stsci.edu/kepler/kepler{sub f}ov/search.php and also via Casjobs at MAST Web site http://mastweb.stsci.edu/kplrcasjobs/).

Greiss, S.; Steeghs, D.; Gaensicke, B. T. [Department of Physics, Astronomy and Astrophysics group, University of Warwick, CV4 7AL Coventry (United Kingdom); Martin, E. L. [INTA-CSIC Centro de Astrobiologia, Carretera de Ajalvir km 4, 28550 Torrejon de Ardoz (Spain); Groot, P. J.; Verbeek, K.; Jonker, P. G.; Scaringi, S. [Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Irwin, M. J.; Gonzalez-Solares, E. [Cambridge Astronomy Survey Unit, Institute of Astronomy, University of Cambridge, Madingley Road, CB3 0HA Cambridge (United Kingdom); Greimel, R. [Institut fuer Physik, Karl-Franzen Universitaet Graz, Universitaetsplatz 5, 8010 Graz (Austria); Knigge, C. [School of Physics and Astronomy, University of Southampton, Southampton, Hampshire SO17 1BJ (United Kingdom); Ostensen, R. H. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium); Drew, J. E.; Farnhill, H. [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Drake, J.; Wright, N. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ripepi, V. [INAF-Osservatorio Astronomico di Capodimonte, via Moiariello 16, Naples I-80131 (Italy); Southworth, J. [Astrophysics Group, Keele University, Newcastle-under-Lyme ST5 5BG (United Kingdom); Still, M., E-mail: s.greiss@warwick.ac.uk [NASA Ames Research Center, M/S 244-40, Moffett Field, CA 94035 (United States); and others

2012-07-15T23:59:59.000Z

313

Limits on Neutrino Emission from Gamma-Ray Bursts with the 40 String IceCube Detector.  

E-Print Network (OSTI)

??Cosmic rays have been observed on Earth with energies in excess of 1020 eV. Because cosmic rays are charged particles and are bent by galactic… (more)

Meagher, Kevin James

2012-01-01T23:59:59.000Z

314

Gamma-Ray Bursts  

E-Print Network (OSTI)

Ultra-high-energy, >10^19 eV, cosmic-ray and high energy, ~10^14 eV, neutrino production in GRBs is discussed in the light of recent GRB and cosmic-ray observations. Emphasis is put on model predictions that can be tested with operating and planned cosmic-ray and neutrino detectors, and on the prospects of testing for neutrino properties.

E. Waxman

2000-04-11T23:59:59.000Z

315

THE NuSTAR EXTRAGALACTIC SURVEY: A FIRST SENSITIVE LOOK AT THE HIGH-ENERGY COSMIC X-RAY BACKGROUND POPULATION  

SciTech Connect

We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array (NuSTAR) to provide the first sensitive census of the cosmic X-ray background source population at {approx}> 10 keV. We find that these NuSTAR-detected sources are Almost-Equal-To 100 times fainter than those previously detected at {approx}> 10 keV and have a broad range in redshift and luminosity (z = 0.020-2.923 and L{sub 10-40{sub keV}} Almost-Equal-To 4 Multiplication-Sign 10{sup 41}-5 Multiplication-Sign 10{sup 45} erg s{sup -1}); the median redshift and luminosity are z Almost-Equal-To 0.7 and L{sub 10-40{sub keV}} Almost-Equal-To 3 Multiplication-Sign 10{sup 44} erg s{sup -1}, respectively. We characterize these sources on the basis of broad-band Almost-Equal-To 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L{sub 10-40{sub keV}} > 10{sup 44} erg s{sup -1}, of which Almost-Equal-To 50% are obscured with N{sub H} {approx}> 10{sup 22} cm{sup -2}. However, none of the 10 NuSTAR sources are Compton thick (N{sub H} {approx}> 10{sup 24} cm{sup -2}) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L{sub 10-40{sub keV}} > 10{sup 44} erg s{sup -1}) selected at {approx}> 10 keV of {approx}< 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame Almost-Equal-To 10-40 keV data for all of the non-beamed sources with L{sub 10-40{sub keV}} > 10{sup 43} erg s{sup -1} to constrain the average strength of reflection; we find R < 1.4 for {Gamma} = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at {approx}> 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of Almost-Equal-To 10{sup 11} M{sub Sun }, a factor Almost-Equal-To 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.

Alexander, D. M.; Del Moro, A.; Lansbury, G. B.; Aird, J. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Stern, D.; Assef, R. J. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Ajello, M.; Boggs, S. E. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Ballantyne, D. R. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Bauer, F. E. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Christensen, F. E.; Craig, W. W. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Civano, F.; Hickox, R. C. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Comastri, A. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Elvis, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Grefenstette, B. W.; Harrison, F. A. [Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, CA 91125 (United States); Hailey, C. J. [Columbia Astrophysics Laboratory, 550 W 120th Street, Columbia University, NY 10027 (United States); and others

2013-08-20T23:59:59.000Z

316

Int. J. Oil, Gas and Coal Technology, Vol. 5, No. 1, 2012 1 Copyright 2012 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

Int. J. Oil, Gas and Coal Technology, Vol. 5, No. 1, 2012 1 Copyright © 2012 Inderscience Reservoir Modelling of Oil and Gas Producing Shale Reservoirs; Case Studies, Int. J. Oil, Gas, and Coal

Mohaghegh, Shahab

317

Int. J. Oil, Gas and Coal Technology, Vol. 1, Nos. 1/2, 2008 65 Copyright 2008 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

Int. J. Oil, Gas and Coal Technology, Vol. 1, Nos. 1/2, 2008 65 Copyright © 2008 Inderscience using neural networks', Int. J. Oil, Gas and Coal Technology, Vol. 1, Nos. 1/2, pp.65­80. Biographical

Mohaghegh, Shahab

318

Compton Recoil Electron Tracking With the TIGRE Gamma-Ray Balloon Experiment  

E-Print Network (OSTI)

AGNs), pulsars, gamma-ray bursts, cosmic ray interactionssensitive to cosmic gamma-ray bursts in the energy range ofGalactic center, a single gamma-ray burst which occurred 10

Kamiya, Kaoru

2011-01-01T23:59:59.000Z

319

Int. J. Fract. manuscript No. (will be inserted by the editor)  

E-Print Network (OSTI)

with experimental data of oil shale [36], microconcrete [37], ceramics and glass [38]. #12;9 It is worth noting, Continuum Modeling of Explosive Fracture in Oil Shale, Int. J. Rock Min. Sci. & Geomech. Abstr. 17 (1980

320

InteMon: continuous mining of sensor data in large-scale self-infrastructures  

Science Conference Proceedings (OSTI)

Modern data centers have a large number of components that must be monitored, including servers, switches/routers, and environmental control systems. This paper describes InteMon, a prototype monitoring and mining system for data centers. It uses the ...

Evan Hoke; Jimeng Sun; John D. Strunk; Gregory R. Ganger; Christos Faloutsos

2006-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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.


321

Fermilab | Science at Fermilab | Experiments & Projects | Cosmic Frontier  

NLE Websites -- All DOE Office Websites (Extended Search)

photo-cosmic photo-cosmic Cosmic Frontier Particle physics experiments at the Cosmic Frontier use the cosmos as a laboratory to investigate the fundamental laws of physics. Researchers use detectors to study particles from space as they approach and enter our atmosphere in forms such as cosmic rays, gamma rays and neutrinos emitted by the sun. These experiments allow researchers to test theories about how the universe was formed, what it is made of and what its future holds. Experiments at the Cosmic Frontier may have the best chance of discovering the nature of dark matter and dark energy. Theorists have concluded that these two mysterious materials constitute 96 percent of the universe and may be responsible for its formation and accelerating expansion. WIMPS and dark matter

322

1st NIFS-CRC Int. Symp. and 1st Korea-Japan WS, 5/20-22, 2007  

E-Print Network (OSTI)

1st NIFS-CRC Int. Symp. and 1st Korea-Japan WS, 5/20-22, 2007 1 Excitation of atomic hydrogen at metal surfaces promoted by proton motion Daiji Kato NIFS #12;1st NIFS-CRC Int. Symp. and 1st Korea of the excited state formation. · Conclusion #12;1st NIFS-CRC Int. Symp. and 1st Korea-Japan WS, 5/20-22, 2007 3

Princeton Plasma Physics Laboratory

323

InteGrade: Object-Oriented Grid Middleware Leveraging Idle Computing Power of Desktop Machines  

E-Print Network (OSTI)

of computing power to solve problems such as financial market simulations and studies for accurate oil well object systems. 1 #12;This allows us to leverage existing services [OMG98], such as Naming, Trading, Transactions, and Persis- tence, shortening development and maintenance time. InteGrade services are exported

Finger, Marcelo

324

Int. J.  

NLE Websites -- All DOE Office Websites (Extended Search)

In their original flavor, HDFS and GoogleFS use a single-node namespace server architecture, which acts as a single container of the file system metadata. Decentralization is...

325

Observation of the Crab Nebula in Soft Gamma Rays with the Nuclear Compton Telescope  

E-Print Network (OSTI)

Gamma-ray bursts . . . . . . . . . . . . . . . . . . . 1.268] G. J. Fishman. The gamma-ray burst capabilities of BATSEOlson. Observations of Gamma- Ray Bursts of Cosmic Origin.

Bandstra, Mark ShenYu

2010-01-01T23:59:59.000Z

326

Light from cosmic strings  

Science Conference Proceedings (OSTI)

The time-dependent metric of a cosmic string leads to an effective interaction between the string and photons--the ''gravitational Aharonov-Bohm'' effect--and causes cosmic strings to emit light. We evaluate the radiation of pairs of photons from cosmic strings and find that the emission from cusps, kinks and kink-kink collisions occurs with a flat spectrum at all frequencies up to the string scale. Further, cusps emit a beam of photons, kinks emit along a curve, and the emission at a kink-kink collision is in all directions. The emission of light from cosmic strings could provide an important new observational signature of cosmic strings that is within reach of current experiments for a range of string tensions.

Steer, Daniele A.; Vachaspati, Tanmay [APC 10 rue Alice Domon et Leonie Duquet, 75205 Paris Cedex 13 (France); Physics Department, Arizona State University, Tempe, Arizona 85287 (United States)

2011-02-15T23:59:59.000Z

327

Int. J. Nuclear Energy Science and Technology, Vol. 4, No. 4, 2009 287 Development of computational methods and their  

E-Print Network (OSTI)

Int. J. Nuclear Energy Science and Technology, Vol. 4, No. 4, 2009 287 Development of computational plants', Int. J. Nuclear Energy Science and Technology, Vol. 4, No. 4, pp.287­298. Biographical notes, energy and temporal distribution of the neutron density throughout the nuclear core depends

Demazière, Christophe

328

198 Int. J. High Performance Computing and Networking, Vol. 4, Nos. 3/4, 2006 Copyright 2006 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

198 Int. J. High Performance Computing and Networking, Vol. 4, Nos. 3/4, 2006 Copyright © 2006 Performance Computing and Networking, Vol. 4, Nos. 3/4, pp.198­206. Biographical notes: Xiao Chen, J. (2006) `Improved schemes for power-efficient broadcast in ad hoc networks', Int. J. High

Shen, Jian - Department of Mathematics, Texas State University

329

104 Int. J. Oil, Gas and Coal Technology, Vol. 4, No. 2, 2011 Copyright 2011 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

approach in modelling and simulation of shale gas reservoirs: application to New Albany Shale', Int. J. Oil104 Int. J. Oil, Gas and Coal Technology, Vol. 4, No. 2, 2011 Copyright © 2011 Inderscience Enterprises Ltd. A new practical approach in modelling and simulation of shale gas reservoirs: application

Mohaghegh, Shahab

330

240 Int. J. Electric and Hybrid Vehicles, Vol. 2, No. 3, 2010 Simulation and analysis of powertrain hybridisation  

E-Print Network (OSTI)

240 Int. J. Electric and Hybrid Vehicles, Vol. 2, No. 3, 2010 Simulation and analysis of powertrain and analysis of powertrain hybridisation for construction equipment', Int. J. Electric and Hybrid Vehicles, Vol). Simulations were performed for two typical duty profiles: roading and lorry loading. Figure 1 An example

Cambridge, University of

331

168 Int. J. Oil, Gas and Coal Technology, Vol. 2, No. 2, 2009 Copyright 2009 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

168 Int. J. Oil, Gas and Coal Technology, Vol. 2, No. 2, 2009 Copyright © 2009 Inderscience.Y. (2009) `Geology and coal potential of Somaliland', Int. J. Oil, Gas and Coal Technology, Vol. 2, No. 2, pp.168­185. Biographical notes: Mohammed Y. Ali has a degree in Exploration Geology, MSc

Ali, Mohammed

332

SLAC National Accelerator Laboratory - Fermi's Latest Gamma-ray...  

NLE Websites -- All DOE Office Websites (Extended Search)

Fermi's Latest Gamma-ray Census Highlights Cosmic Mysteries By Francis Reddy, NASAGoddard Space Flight Center September 9, 2011 Every three hours, NASA's Fermi Gamma-ray Space...

333

Measurement of the Cosmic Ray e+ plus e- Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope  

SciTech Connect

Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2 m{sup 2}sr at 300 GeV. Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply-falling electron spectrum up to 1 TeV. Our high precision data show that the electron spectrum falls with energy as E{sup -3.0} and does not exhibit prominent spectral features. Interpretations in terms of a conventional diffusive model as well as a potential local extra component are briefly discussed.

Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U., OKC /Stockholm U.; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, Guido; /INFN, Trieste /Trieste U.; Bastieri, Denis; /INFN, Padua /Padua U.; Battelino, M.; /Stockholm U., OKC /Royal Inst. Tech., Stockholm; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Blandford, R.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, Elliott D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bogaert, G.; /Ecole Polytechnique; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa /Bari U. /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /IASF, Milan /Stockholm U., OKC /Royal Inst. Tech., Stockholm /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /George Mason U. /Naval Research Lab, Wash., D.C. /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Sonoma State U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /Stockholm U. /ASDC, Frascati /Naval Research Lab, Wash., D.C. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Pisa /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Bari U. /INFN, Bari; /more authors..

2012-05-14T23:59:59.000Z

334

Observing air showers from cosmic superluminal particles  

Science Conference Proceedings (OSTI)

The Poincare relativity principle has been tested at low energy with great accuracy, but its extrapolation to very high-energy phenomena is much less well established. Lorentz symmetry can be broken at Planck scale due to the renormalization of gravity or to some deeper structure of matter: we expect such a breaking to be a very high energy and very short distance phenomenon. If textbook special relativity is only an approximate property of the equations describing a sector of matter above some critical distance scale, an absolute local frame (the 'vacuum rest frame', VRF) can possibly be found and superluminal sectors of matter may exist related to new degrees of freedom not yet discovered experimentally. The new superluminal particles ('superbradyons', i.e. bradyons with superluminal critical speed) would have positive mass and energy, and behave kinematically like 'ordinary' particles (those with critical speed in vacuum equal to c, the speed of light) apart from the difference in critical speed (we expect c{sub i}>>c, where c{sub i} is the critical speed of a superluminal sector). They may be the ultimate building blocks of matter. At speed v>c, they are expected to release ''Cherenkov'' radiation ('ordinary' particles) in vacuum. Superluminal particles could provide most of the cosmic (dark) matter and produce very high-energy cosmic rays. We discuss: a) the possible relevance of superluminal matter to the composition, sources and spectra of high-energy cosmic rays; b) signatures and experiments allowing to possibly explore such effects. Very large volume and unprecedented background rejection ability are crucial requirements for any detector devoted to the search for cosmic superbradyons. Future cosmic-ray experiments using air-shower detectors (especially from space) naturally fulfil both requirements.

Gonzalez-Mestres, Luis [Laboratoire de Physique Corpusculaire, College de France, 75231 Paris Cedex 05 (France); L.A.P.P., CNRS-IN2P3, B.P. 110, 74941 Annecy-le-Vieux Cedex (France)

1998-06-15T23:59:59.000Z

335

Cosmic Microwave Background Project at NERSC  

NLE Websites -- All DOE Office Websites (Extended Search)

Cosmic Microwave Background Cosmic Microwave Background CMB.jpg The Cosmic Microwave Background (CMB) is relic radiation from a very early stage in the universe -- essentially a...

336

The Cosmic Energy Inventory  

E-Print Network (OSTI)

We present an inventory of the cosmic mean densities of energy associated with all the known states of matter and radiation at the present epoch. The observational and theoretical bases for the inventory have become rich enough to allow estimates with observational support for the densities of energy in some 40 forms. The result is a global portrait of the effects of the physical processes of cosmic evolution.

Masataka Fukugita; P. J. E. Peebles

2004-06-03T23:59:59.000Z

337

Gamma-ray Astronomy  

E-Print Network (OSTI)

The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

Hinton, Jim

2007-01-01T23:59:59.000Z

338

Gamma-ray Astronomy  

E-Print Network (OSTI)

The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

Jim Hinton

2007-12-20T23:59:59.000Z

339

The Cosmic Stellar Birth and Death Rates  

E-Print Network (OSTI)

The cosmic stellar birth rate can be measured by standard astronomical techniques. It can also be probed via the cosmic stellar death rate, though until recently, this was much less precise. However, recent results based on measured supernova rates, and importantly, also on the attendant diffuse fluxes of neutrinos and gamma rays, have become competitive, and a concordant history of stellar birth and death is emerging. The neutrino flux from all past core-collapse supernovae, while faint, is realistically within reach of detection in Super-Kamiokande, and a useful limit has already been set. I will discuss predictions for this flux, the prospects for neutrino detection, the implications for understanding core-collapse supernovae, and a new limit on the contribution of type-Ia supernovae to the diffuse gamma-ray background.

John F. Beacom

2006-02-05T23:59:59.000Z

340

2 Int. J. Oil, Gas and Coal Technology, Vol. 2, No. 1, 2009 Copyright 2009 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

2 Int. J. Oil, Gas and Coal Technology, Vol. 2, No. 1, 2009 Copyright © 2009 Inderscience, Gas, and Coal Technology, Vol. 2, No. 1, pp.2­23. Biographical notes: Shahab D. Mohaghegh is currently

Mohaghegh, Shahab

Note: This page contains sample records for the topic "int cosmic ray" 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

THOREX PILOT PLANT: CRITICALITY REVIEW OF THE THOREX PILOT PLANT USING THE INT-23 PROCESS  

SciTech Connect

The results of a criticality review of the ORNL Thorex pilot plant are presented for the condition where a low TBP (INT-23) flowsheet is used in recovering U/sup 233/ from irradiated thorium. Criticality control will be maintained by limiting the U/sup 233/ inventory in the solvent extraction system to less than 550g by means of streamvolume and U/sup 233/ material balances determined at 8 hr intervals. Equipment modification and improved operating procedures for safe plant operation are outlined. (auth)

McDuffee, W.T.; Yarbro, O.O.

1958-07-01T23:59:59.000Z

342

A disintegrating cosmic string  

E-Print Network (OSTI)

We present a simple sandwich gravitational wave of the Robinson-Trautman family. This is interpreted as representing a shock wave with a spherical wavefront which propagates into a Minkowski background minus a wedge. (i.e. the background contains a cosmic string.) The deficit angle (the tension) of the string decreases through the gravitational wave, which then ceases. This leaves an expanding spherical region of Minkowski space behind it. The decay of the cosmic string over a finite interval of retarded time may be considered to generate the gravitational wave.

J. B. Griffiths; P. Docherty

2002-04-29T23:59:59.000Z

343

The Cosmic Ray Muon Flux at WIPP  

E-Print Network (OSTI)

In this work a measurement of the muon intensity at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM, USA is presented. WIPP is a salt mine with a depth of 655 m. The vertical muon flux was measured with a two panels scintillator coincidence setup to Phi_{vert}=3.10(+0.05/-0.07)*10^(-7)s^(-1)cm^(-2)sr^(-1).

E. -I. Esch; T. J. Bowles; A. Hime; A. Pichlmaier; R. Reifarth; H. Wollnik

2004-08-25T23:59:59.000Z

344

The Cosmic Ray Muon Flux at WIPP  

E-Print Network (OSTI)

In this work a measurement of the muon intensity at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM, USA is presented. WIPP is a salt mine with a depth of 655 m. The vertical muon flux was measured with a two panels scintillator coincidence setup to ?vert = (3.10 +0.05 ?0.07) 10?7 s ?1 cm ?2 sr ?1.

E. -i. Esch A; T. J. Bowles A; A. Hime A; A. Pichlmaier A; R. Reifarth A; H. Wollnik B

2004-01-01T23:59:59.000Z

345

The Cosmic Ray Muon Flux at WIPP  

E-Print Network (OSTI)

In this work a measurement of the muon intensity at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM, USA is presented. WIPP is a salt mine with a depth of 655 m. The vertical muon flux was measured with a two panels scintillator coincidence setup to Phi_{vert}=3.10(+0.05/-0.07)*10^(-7)s^(-1)cm^(-2)sr^(-1).

Esch, E I; Hime, A; Pichlmaier, A; Reifarth, R; Wollnik, H

2005-01-01T23:59:59.000Z

346

Obtaining material identification with cosmic ray radiography  

SciTech Connect

The passage of muons through matter is dominated by the Coulomb interaction with electrons and nuclei in the matter. The muon interaction with the electrons leads to continuous energy loss and stopping of the muons. The muon interaction with nuclei leads to angular diffusion. Using both stopped muons and angle diffusion interactions allows us to determine density and identify materials. Here we demonstrate material identification using data taken at Los Alamos with a particle tracker built from a set of sealed drift tubes with commercial electronics and software, the Mini Muon Tracker (MMT).

Morris, C. L.; Borozdin, Konstantin; Bacon, Jeffrey; Chen, Elliott; Lukic, Zarija; Milner, Edward; Miyadera, Haruo; Perry, John [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Schwellenbach, Dave; Aberle, Derek; Dreesen, Wendi; Green, J. Andrew; McDuff, George G. [National Security Technologies, Los Alamos, NM 87544 (United States); Nagamine, Kanetada [KEK, Tsukuba, Ibaraki, 305-0801 (Japan); RIKEN, Wako, Saitama, 351-0198 (Japan) and UC-Riverside, CA 92521 (United States); Sossong, Michael [Decision Sciences, 12345 First American Way, Suite 130, Poway, CA 92064 (United States); Spore, Candace; Toleman, Nathan [Department of Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131-0001 (United States)

2012-12-15T23:59:59.000Z

347

Experiments at the Cosmic Frontier | U.S. DOE Office of Science (SC)  

NLE Websites -- All DOE Office Websites (Extended Search)

Cosmic Frontier Cosmic Frontier High Energy Physics (HEP) HEP Home About Research Facilities Facility Ops Experiments at the Energy Frontier Experiments at the Intensity Frontier Experiments at the Cosmic Frontier Projects, Missions, and Status HEP User Facilities Science Highlights Benefits of HEP Funding Opportunities Advisory Committees News & Resources Contact Information High Energy Physics U.S. Department of Energy SC-25/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3624 F: (301) 903-2597 E: sc.hep@science.doe.gov More Information » Facilities Experiments at the Cosmic Frontier Print Text Size: A A A RSS Feeds FeedbackShare Page The Cosmic Frontier reveals the nature of dark matter and dark energy by using particles from space to explore new phenomena. Cosmic rays in the

348

Stable Charged Cosmic Strings  

Science Conference Proceedings (OSTI)

We study the quantum stabilization of a cosmic string by a heavy fermion doublet in a reduced version of the standard model. We show that charged strings, obtained by populating fermionic bound state levels, become stable if the electroweak bosons are coupled to a fermion that is less than twice as heavy as the top quark. This result suggests that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model. Numerically we find the most favorable string profile to be a simple trough in the Higgs vacuum expectation value of radius {approx_equal}10{sup -18} m. The vacuum remains stable in our model, because neutral strings are not energetically favored.

Weigel, H. [Physics Department, Stellenbosch University, Matieland 7602 (South Africa); Quandt, M. [Institute for Theoretical Physics, Tuebingen University, D-72076 Tuebingen (Germany); Graham, N. [Department of Physics, Middlebury College , Middlebury, Vermont 05753 (United States)

2011-03-11T23:59:59.000Z

349

A COSMIC BATTERY RECONSIDERED G. S. Bisnovatyi-Kogan  

E-Print Network (OSTI)

A COSMIC BATTERY RECONSIDERED G. S. Bisnovatyi-Kogan Space Research Institute, Russian Academy: magnetic fields -- X-rays: stars 1. INTRODUCTION The classical battery mechanism of magnetic field genera currents and an associated magnetic field. Self-induction is very impor- tant in the battery mechanism

350

ORIGIN: metal creation and evolution from the cosmic dawn  

E-Print Network (OSTI)

ORIGIN is a proposal for the M3 mission call of ESA aimed at the study of metal creation from the epoch of cosmic dawn. Using high-spectral resolution in the soft X-ray band, ORIGIN will be able to identify the physical ...

Figueroa-Feliciano, Enectali

351

288 Int. J. Nuclear Energy Science and Technology, Vol. 7, No. 4, 2013 Multi-physics modelling of nuclear reactors  

E-Print Network (OSTI)

288 Int. J. Nuclear Energy Science and Technology, Vol. 7, No. 4, 2013 Multi-physics modelling of nuclear reactors: current practices in a nutshell Christophe Demazière Department of Applied Physics, Division of Nuclear Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden Email

Demazière, Christophe

352

160 Int. J. Energy Technology and Policy, Vol. 9, No. 2, 2013 Copyright 2013 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

160 Int. J. Energy Technology and Policy, Vol. 9, No. 2, 2013 Copyright © 2013 Inderscience Enterprises Ltd. A strategic energy technology policy towards 2050: no-regret strategies for European-michel.glachant@eui.eu Abstract: As current policy frameworks are expiring soon, the EU is revisiting its energy technology policy

Candea, George

353

int. j. remote sensing, 2002, vol. 23, no. 3, 537553 EVect of spatial resolution on information content characterization in  

E-Print Network (OSTI)

int. j. remote sensing, 2002, vol. 23, no. 3, 537­553 EVect of spatial resolution on information content characterization in remote sensing imagery based on classi cation accuracy R. M. NARAYANAN*, M. K) Abstract. The information content of remote sensing imagery depends upon various factors such as spatial

Reichenbach, Stephen E.

354

Int. J. Global Energy Issues, Vol. 23, No. 4, 2005 307 Canada's efforts towards greenhouse gas emission  

E-Print Network (OSTI)

Int. J. Global Energy Issues, Vol. 23, No. 4, 2005 307 Canada's efforts towards greenhouse gas greenhouse gas emissions reductions. Without a major change in direction towards more compulsory policies, it seems unlikely that Canada will achieve significant domestic greenhouse gas reductions over and beyond

355

246 Int. J. Electric and Hybrid Vehicles, Vol. 3, No. 3, 2011 Copyright 2011 Inderscience Enterprises Ltd.  

E-Print Network (OSTI)

246 Int. J. Electric and Hybrid Vehicles, Vol. 3, No. 3, 2011 Copyright © 2011 Inderscience@ieee.org *Corresponding author Abstract: This paper studies the power management of a plug-in hybrid electric vehicle-based strategy; quadratic programming; QP; plug-in hybrid electric vehicle; PHEV; electric and hybrid vehicles

Mi, Chunting "Chris"

356

Cosmic Growth History and Expansion History  

E-Print Network (OSTI)

LBNL- 58260 Cosmic Growth History andExpansion History Eric V. Linder Physics Division, LawrenceCalifornia. Cosmic Growth History and Expansion History Eric

Linder, Eric V.

2009-01-01T23:59:59.000Z

357

POLARIZATION OF THE COSMIC BACKGROUND RADIATION  

E-Print Network (OSTI)

Galactic Synchrotron Radiation at 33 GHz NOIiWNPQaa s x s sthe Cosmic Background Radiation Philip Michael Lubin Spacethe Cosmic Background Radiation. The ground-based experiment

Lubin, Philip Lubin

2010-01-01T23:59:59.000Z

358

Cosmic Strings in Supergravity  

E-Print Network (OSTI)

It is pointed out that various types of cosmic string solutions that exist in nonsupersymmetric and globally supersymmetric theories, such as D-type gauge strings, F-type global and gauge strings, and superconducting Witten strings, also exist in supergravity models. When the D term and superpotential satisfy some simple conditions allowing the determination of a set of vacuum states with nontrivial topology, the existence of a string embedded within a supersymmetric vacuum with vanishing cosmological constant can be inferred. Supergravity also admits other string solutions, some of which have no counterparts in globally supersymmetric theories.

J. R. Morris

1997-06-09T23:59:59.000Z

359

Searching for gravitational waves associated with gamma-ray bursts int 2009-2010 ligo-virgo data.  

E-Print Network (OSTI)

??Cette thèse présente les résultats de la recherche de signaux impulsionnels d’ondes gravitationnelles associés aux sursauts gamma dans les données 2009-2010 des interféromètres LIGO-Virgo. L’étude… (more)

Was, Michal

2011-01-01T23:59:59.000Z

360

Searching for gravitational waves associated with gamma-ray bursts int 2009-2010 ligo-virgo data.  

E-Print Network (OSTI)

??Cette thèse présente les résultats de la recherche de signaux impulsionnels d'ondes gravitationnelles associés aux sursauts gamma dans les données 2009-2010 des interféromètres LIGO-Virgo. L'étude… (more)

Was, Michal

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "int cosmic ray" 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

Signatures of Cosmic Strings in the Cosmic Microwave Background  

E-Print Network (OSTI)

We report a search for signatures of cosmic strings in the the Cosmic Microwave Background data from the Wilkinson Microwave Anisotropy Probe. We used a digital filter designed to search for individual cosmic strings and found no evidence for them in the WMAP CMB anisotropies to a level of $\\Delta T/T \\sim 0.29$ mK. This corresponds to an absence of cosmic strings with $ G\\mu \\ga 1.07 \\times 10^{-5}$ for strings moving with velocity $v = c/\\sqrt{2}$. Unlike previous work, this limit does not depend on an assumed string abundance. We have searched the WMAP data for evidence of a cosmic string recently reported as the CSL-1 object, and found an ``edge'' with 2$\\sigma$ significance. However, if this edge is real and produced by a cosmic string, it would have to move at velocity $\\ga$ 0.94c. We also present preliminary limits on the CMB data that will be returned by the PLANCK satellite for comparison. With the available information on the PLANCK satellite, we calculated that it would be twice as sensitive to cosmic strings as WMAP.

Amy S. Lo; Edward L. Wright

2005-03-05T23:59:59.000Z

362

Gamma ray bursts ROBERT S MACKAY  

E-Print Network (OSTI)

Gamma ray bursts ROBERT S MACKAY COLIN ROURKE We propose that a gamma ray burst is a kinematic Gamma ray bursts are intense flashes of electromagnetic radiation of cosmic origin lasting from ten accepted mechanism. We propose that a gamma ray burst is simply a kinematic effect, namely the effect

Rourke, Colin

363

Gamma-ray bursts: a Centauro's cry?  

E-Print Network (OSTI)

A new candidate for the gamma-ray bursts central engine is proposed: if in some energetic cosmic event a macroscopic amount of bubbles of the disoriented chiral condensate can be formed, then their subsequent decays will produce a relativistic fireball without the baryon loading problem. The neutron star to strange star transition is considered as a candidate example of such cosmic event.

Z. K. Silagadze

2003-03-04T23:59:59.000Z

364

Cosmic Frontier | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Cosmic Frontier High Energy Physics (HEP) HEP Home About Research Snowmass P5 Planning Process Energy Frontier Intensity Frontier Cosmic Frontier Cosmic Frontier: More...

365

Cosmic string induced CMB maps  

SciTech Connect

We compute maps of CMB temperature fluctuations seeded by cosmic strings using high resolution simulations of cosmic strings in a Friedmann-Robertson-Walker universe. We create full-sky, 18 deg. and 3 deg. CMB maps, including the relevant string contribution at each resolution from before recombination to today. We extract the angular power spectrum from these maps, demonstrating the importance of recombination effects. We briefly discuss the probability density function of the pixel temperatures, their skewness, and kurtosis.

Landriau, M. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching (Germany); Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Shellard, E. P. S. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

2011-02-15T23:59:59.000Z

366

Semantic image interpretation of gamma ray profiles in petroleum exploration  

Science Conference Proceedings (OSTI)

This paper presents the S-Chart framework, an approach for semantic image interpretation of line charts; and the InteliStrata system, an application for semantic interpretation of gamma ray profiles. The S-Chart framework is structured as a set of knowledge ... Keywords: Gamma ray well log, Ontology, Semantic image interpretation, Stratigraphy, Symbol grounding problem, Visual knowledge

Sandro Rama Fiorini; Mara Abel; Claiton M. S. Scherer

2011-04-01T23:59:59.000Z

367

The Growth of Supermassive Black Holes Across Cosmic Time  

E-Print Network (OSTI)

One of the main themes in extragalactic astronomy for the next decade will be the evolution of galaxies over cosmic time. Many future observatories, including JWST, ALMA, GMT, TMT and E-ELT will intensively observe starlight over a broad redshift range, out to the dawn of the modern Universe when the first galaxies formed. It has, however, become clear that the properties and evolution of galaxies are intimately linked to the growth of their central black holes. Understanding the formation of galaxies, and their subsequent evolution, will therefore be incomplete without similarly intensive observations of the accretion light from supermassive black holes (SMBH) in galactic nuclei. To make further progress, we need to chart the formation of typical SMBH at z>6, and their subsequent growth over cosmic time, which is most effectively achieved with X-ray observations. Recent technological developments in X-ray optics and instrumentation now bring this within our grasp, enabling capabilities fully matched to those...

Nandra, K; Alexander, D M; Ballantyne, D R; Barcons, X; Bauer, F E; Boller, T; Brandt, W N; Brusa, M; Cattaneo, A; Chartas, G; Coil, A L; Comastri, A; Croton, D J; Della Ceca, R; Dickinson, M; Fabian, A C; Fazio, G G; Fiore, F; Flanagan, K A; Forman, W R; Gehrels, N; Georgakakis, A; Georgantopoulos, I; Gilli, R; Hasinger, G; Hopkins, P F; Hornschemeier, A E; Ivison, R J; Kauffmann, G; King, A R; Koekemoer, A M; Koo, D C; Kunieda, H; Laird, E S; Levenson, N A; Li, Y; Madau, P; Ohashi, T; Pounds, K A; Primack, J R; Ranalli, P; Ricker, G R; Rossi, E M; Shemmer, O; Somerville, R S; Stern, D; Stiavelli, M; Tananbaum, H; Terashima, Y; Treister, E; Ueda, Y; Vignali, C; Volonteri, M; Watson, M G; White, N E; White, S D M

2009-01-01T23:59:59.000Z

368

Geophys. J. Int. (2005) 163, 952955 doi: 10.1111/j.1365-246X.2005.02794.x GJISeismology  

E-Print Network (OSTI)

for BDKs but, effec- tively, render `fat ray' kernels with negative sensitivity on the ray (see HH05

van der Hilst, Robert Dirk

369

Results from the Milagro Gamma-Ray Observatory  

E-Print Network (OSTI)

V energies, and a search for transient emission above 100 GeV from gamma-ray bursts. 1 Introduction remnants and gamma-ray bursts (GRB). Gamma rays are also produced when high-energy cosmic rays interactResults from the Milagro Gamma-Ray Observatory E. Blaufuss for the Milagro Collaboration a,1 , a

California at Santa Cruz, University of

370

Clusters and the Cosmic Web  

E-Print Network (OSTI)

We discuss the intimate relationship between the filamentary features and the rare dense compact cluster nodes in this network, via the large scale tidal field going along with them, following the cosmic web theory developed Bond et al. The Megaparsec scale tidal shear pattern is responsible for the contraction of matter into filaments, and its link with the cluster locations can be understood through the implied quadrupolar mass distribution in which the clusters are to be found at the sites of the overdense patches. We present a new technique for tracing the cosmic web, identifying planar walls, elongated filaments and cluster nodes in the galaxy distribution. This will allow the practical exploitation of the concept of the cosmic web towards identifying and tracing the locations of the gaseous WHIM. These methods, the Delaunay Tessellation Field Estimator (DTFE) and the Morphology Multiscale Filter (MMF) find their basis in computational geometry and visualization.

Rien van de Weygaert

2006-07-24T23:59:59.000Z

371

Scanning Lidar Based Atmospheric Monitoring for Fluorescent Detectors of Cosmic Showers  

E-Print Network (OSTI)

Measurements of the cosmic-ray air-shower fluorescence at extreme energies require precise knowledge of atmospheric conditions. The absolute calibration of the cosmic-ray energy depends on the absorption of fluorescence light between its origin and point of its detection. To reconstruct basic atmospheric parameters we review a novel analysis method based on two- and multi-angle measurements performed by the scanning backscatter lidar system. Applied inversion methods, optical depth, absorption and backscatter coefficient, as well as other parameters that enter the lidar equation are discussed in connection to the attenuation of the light traveling from shower to fluorescence detector.

A. Filipcic; M. Horvat; D. Veberic; D. Zavrtanik; M. Zavrtanik

2002-02-06T23:59:59.000Z

372

Reheating and Cosmic String Production  

E-Print Network (OSTI)

We compute the string production rate at the end of inflation, using the string spectrum obtained in \\lss in a near-de Sitter space. Our result shows that highly excited strings are hardly produced, thus the simple slow-roll inflation alone does not offer a cosmic string production mechanism.

Chao-Jun Feng; Xian Gao; Miao Li; Wei Song; Yushu Song

2007-07-06T23:59:59.000Z

373

ON THE ORIGIN OF THE SOLAR COMPONENT OF COSMIC RADIATION  

SciTech Connect

Ascending prominences in the outer corona often reach velocities above 600 km/sec, 3 times the thermal velocity of coronal protons. lt is not probable that such prominences move through the corona. lt seems much more probable that prominences and the surrounding corona are lifted together by the sarne force. Coronal films give some evidence in this direction. There can be no doubt thai the acceleration force is of a magnetic nature. Under such circumstances, a kind of hollow cavity is formed. Such low-density cavities represent very favorable conditions for the acceleration of cosmic particles. This type of mechanism has the advantage of explaining in a natural way the observed delay between the begirning of a flare and the terrestrial onset of the cosmic-ray burst. (A.C.)

Kiepenheuer, K.O.

1958-01-01T23:59:59.000Z

374

The Universe Viewed in Gamma-Rays 1 Properties of Gamma-ray Bursts Localized by  

E-Print Network (OSTI)

The short gamma-ray burst ­ SGR giant flare connection Kevin Hurley University of California cosmic gamma-ray bursts. There are at least two general ways to approach this problem. One is statistical short gamma-ray bursts (GRBs) could actually be extragalactic giant magnetar flares is not new by any

Enomoto, Ryoji

375

Masatoshi Koshiba and Cosmic Neutrinos  

Office of Scientific and Technical Information (OSTI)

Masatoshi Koshiba and Cosmic Neutrinos Masatoshi Koshiba and Cosmic Neutrinos Resources with Additional Information Masatoshi Koshiba Courtesy of Sebastian Brandt 'The 2002 Nobel Prize in Physics has been awarded to ... Masatoshi Koshiba of the International Center for Elementary Particle Physics at the University of Tokyo in Japan, ... "for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos." ... Neutrinos are important in astrophysics since they might have played a considerable role in shaping early galaxies; they are the form of energy coming directly from the solar core; and they account for the largest share of energy released during supernova explosions....'1 ...Koshiba, professor emeritus at the University of Tokyo, received his doctorate from the University of Rochester in [1955]. This year [2000], he is the co-recipient of the Wolf Prize in Physics, considered second only to the Nobel Prize in prestige, for his discovery that neutrinos have mass. Neutrinos are tiny particles smaller than atoms, and Koshiba's discovery is being hailed for its ramifications in the study of astronomical objects and the fundamental properties of matter, helping scientists to understand the birth of the universe. Koshiba started his career as a research associate at the University of Rochester, then went on to teach at the University of Tokyo." 2

376

Detection of Ionizing Radiation by Plasma-Panel Sensors: Cosmic Muons, Ion Beams, and Cancer Therapy  

Science Conference Proceedings (OSTI)

The plasma panel sensor is an ionizing photon and particle radiation detector derived from PDP technology with high gain and nanosecond response. Experimental results in detecting cosmic ray muons and beta particles from radioactive sources are described along with applications including high energy and nuclear physics, homeland security and cancer therapeutics.

Friedman, Dr. Peter S. [Integrated Sensors, LLC; Ferretti, Claudio [University of Michigan; Ball, Robert [University of Michigan; Beene, James R [ORNL; Ben Moshe, M. [Tel Aviv University; Benhammou, Yan [Tel Aviv University; Chapman, J. Wehrley [University of Michigan; Levin, Daniel S. [University of Michigan; Silver, Yiftah [Tel Aviv University; Weaverdyck, Curtis [University of Michigan; Zhou, Bing [University of Michigan; Etzion, E [Tel Aviv University; Moshe, M. [Tel Aviv University; Bentefour, E [Ion Beam Applications

2012-01-01T23:59:59.000Z

377

Dark matter searches with cosmic antideuterons: status and perspectives  

E-Print Network (OSTI)

The search for antideuterons in cosmic rays has been proposed as a promising channel for dark matter indirect detection, especially for dark matter particles with a low or intermediate mass. With the current operational phase of the AMS-02 experiment and the ongoing development of a future dedicated experiment, the General Antiparticle Spectrometer (GAPS), there are exciting prospects for a dark matter detection in the near future. In this paper we develop a detailed and complete re-analysis of the cosmic-ray antideuteron signal, by discussing the main relevant issues related to antideuteron production and propagation through the interstellar medium and the heliosphere. In particular, we first critically revisit the coalescence mechanism for antideuteron production in dark matter annihilation processes. Then, since antideuteron searches have their best prospects of detection at low kinetic energies where the effect of the solar wind and magnetic field are most relevant, we address the impact of solar modulation modeling on the antideuteron flux at the Earth by developing a full numerical 4D solution of cosmic rays transport in the heliosphere. We finally use these improved predictions to provide updated estimates of the reaching capabilities for AMS-02 and GAPS, compatible with the current constraints imposed by the antiprotons measurements of PAMELA. After the antiproton bound is applied, prospects of detection of up to about 15 events in GAPS LDB+ and AMS-02 missions are found, depending on the dark matter mass, annihilation rate and production channel from one side, and on the coalescence process, galactic and solar transport parameters on the other.

N. Fornengo; L. Maccione; A. Vittino

2013-06-18T23:59:59.000Z

378

2nd Int. Symp. on Lithium Applications for Fusion Devices, April 27-29, 2011, Princeton, NJ Program for the 2nd International Symposium  

E-Print Network (OSTI)

2nd Int. Symp. on Lithium Applications for Fusion Devices, April 27-29, 2011, Princeton, NJ Program for the 2nd International Symposium on Lithium Applications for Fusion Devices April 27-29, 2011:40 Welcome, S. Prager, Director, PPPL 8:45 Announcement: Local organizer Session I-A. Lithium in Magnetic

Princeton Plasma Physics Laboratory

379

int. j. remote sensing, 1999, vol. 20, no. 17, 3281 3291 A remote sensing and GIS-based model of habitats and biodiversity in  

E-Print Network (OSTI)

int. j. remote sensing, 1999, vol. 20, no. 17, 3281± 3291 A remote sensing and GIS-based model, University of Kansas, Lawrence, KS 66047, USA and §Kansas Applied Remote Sensing (KARS) Program, 2291 Irving 31 May 1998) Abstract. We used remotely sensed data and geographical information systems (GIS

Debinski, Diane M.

380

Int. J. of Heavy Vehicle Systems, Vol. 11, Nos 3/4, 2004 434 Towards computer-aided reverse engineering of  

E-Print Network (OSTI)

Int. J. of Heavy Vehicle Systems, Vol. 11, Nos 3/4, 2004 434 Towards computer-aided reverse engineering of heavy vehicle parts using laser range imaging techniques D. Page, A. Koschan, Y. Sun, Y. Zhang-aided reverse engineering (CARE), heavy vehicles, image-based modelling, reverse engineering, vehicle modelling

Abidi, Mongi A.

Note: This page contains sample records for the topic "int cosmic ray" 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.


381

Heavy Vehicle Systems, Int. J. of Vehicle Design, Vol. 11, Nos. 3/4, 2004 349 Modelling and control of a medium-duty hybrid  

E-Print Network (OSTI)

engine. Keywords: electric vehicles, electric-vehicle simulation, hybrid electric vehicles, hybrid-duty hybrid electric truck', Int. J. of Heavy Vehicle Systems, Vol. 11, Nos. 3/4, pp. 349­370. 1 Introduction. Hybrid-electric vehicles (HEV) appear to be one of the most viable technologies with significant

Peng, Huei

382

The Kurtosis of the Cosmic Shear Field  

E-Print Network (OSTI)

We study the fourth-order moment of the cosmic shear field using the dark matter halo approach to describe the nonlinear gravitational evolution of structure in the universe. Since the third-order moment of the shear field vanishes because of symmetry, non-Gaussian signatures in its one-point statistics emerge at the fourth-order level. We argue that the shear kurtosis parameter S_4 = /^3 may be more directly applicable to realistic data than the well-studied higher-order statistics of the convergence field, since obtaining the convergence requires a non-local reconstruction from the measured shear field. We compare our halo model predictions for the variance, skewness and kurtosis of lensing fields with ray-tracing simulations of cold dark matter models and find good agreement. The shear kurtosis calculation is made tractable by developing approximations for fast and accurate evaluations of the 8-dimensional integrals needed to obtain the kurtosis. We show that on small scales it is dominated by correlations within halos more massive than 10^14 solar masses. The shear kurtosis is sensitive to the mass density parameter of the universe, Omega, and has relatively weak dependences on other parameters. The approximations we develop for the third- and fourth-order moments allow for accurate halo model predictions for the 3-dimensional mass distribution as well. We demonstrate their accuracy in the small scale regime, below 2 Mpc, where analytical approaches used in the literature so far cease to be accurate.

Masahiro Takada; Bhuvnesh Jain

2002-05-05T23:59:59.000Z

383

A Gamma-Ray Burst Bibliography, 1973-1999  

E-Print Network (OSTI)

On the average, one new publication on cosmic gamma-ray bursts enters the literature every day. The total number now exceeds 4100. I present here a complete bibliography which can be made available electronically to interested parties.

K. Hurley

1999-12-02T23:59:59.000Z

384

SLAC National Accelerator Laboratory - X-ray Laser Takes Aim...  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser Takes Aim at Cosmic Mystery December 12, 2012 Menlo Park, Calif. - Scientists have used powerful X-rays from the Linac Coherent Light Source (LCLS) at the U.S. Department of...

385

NERSC Continues Tradition of Cosmic Microwave Background Data...  

NLE Websites -- All DOE Office Websites (Extended Search)

Tradition of Cosmic Microwave Background Data Analysis with the Planck Cluster NERSC Continues Tradition of Cosmic Microwave Background Data Analysis with the Planck...

386

Section II INT  

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IN (01-12-2010) Title: Standard Terms & Conditions for International Commercial Transactions Owner: Procurement Policy & Quality Dept Initial Release Date: 011210 Page 1 of 6...

387

Section II INT  

control system to an industry recognized Quality Standard for any work performed under this contract. Records of all quality control inspections

388

PROCEEDINGS INTE RNATIONAL  

E-Print Network (OSTI)

, MASSACHUSETTS USA 24-29 JUNE 1979 #12;International Committee G. S. Ansell (USA) J. S. Bowles (Australia) J. W Science and Engineering Massachusetts Institute of Technology Cambridge, Massachusetts 02139 - ii - #12

Cambridge, University of

389

Section II INT  

District of New Mexico. ... clauses and Department of Energy Acquisition Regulation (DEAR) clauses. The full text of these clauses may be found at ...

390

Neutrinos from Gamma Ray Bursts  

E-Print Network (OSTI)

The observed fluxes of cosmic rays and gamma rays are used to infer the maximum allowed high-energy neutrino flux allowed for Gamma Ray Bursts (GRBs), following Mannheim, Protheroe, and Rachen (2000). It is shown that if GRBs produce the ultrahigh-energy cosmic rays, they should contribute (a) at least 10% of the extragalactic gamma ray background between 3 MeV and 30 GeV, contrary to their observed energy flux which is only a minute fraction of this flux, and (b) a cumulative neutrino flux a factor of 20 below the AMANDA (Neutrino 2000) limit on isotropic neutrinos. This could have two implications, either GRBs do not produce the ultrahigh energy cosmic rays or that the GRBs are strongly beamed and emit most of their power at energies well above 100 GeV implausibly increasing the energy requirements, but consistent with the marginal detections of a few low-redshift GRBs by MILAGRITO, HEGRA-AIROBICC, and the Tibet-Array. All crucial measurements to test the models will be available in the next few years. These are measurements of (i) high-energy neutrinos with AMANDA-ICECUBE or an enlarged ANTARES/NESTOR ocean detector, (ii) GRB redshifts from HETE-2 follow-up studies, and (iii) GRB spectra above 10 GeV with low-threshold imaging air Cherenkov telescopes such as MAGIC and the space telescopes AGILE and GLAST.

Karl Mannheim

2000-10-18T23:59:59.000Z

391

Reading the Cosmic Writing on the Wall  

NLE Websites -- All DOE Office Websites (Extended Search)

Reading the Cosmic Reading the Cosmic Writing on the Wall Reading the Cosmic Writing on the Wall NERSC Key to Planck's Revision of Universal Recipe March 21, 2013 Contact: Margie Wylie, mwylie@lbl.gov, + 1 510 486 7421 map800-600.jpg This map shows the oldest light in our universe, as detected with the greatest precision yet by the Planck mission. The ancient light, called the cosmic microwave background, was imprinted on the sky when the universe was 370,000 years old. (Image credit: ESA and the Planck Collaboration) Thanks to a supersensitive space telescope and some sophisticated supercomputing, scientists from the international Planck collaboration have made the closest reading yet of the most ancient story in our universe: the cosmic microwave background (CMB). Today, the team released preliminary results based on the Planck

392

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

SciTech Connect

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 µ-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 µ-Witness detector with Geant4 simulations in order to assure our understanding of the µ-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

393

NERSC Helps Discover Cosmic Transients - NERSC Science News June 15, 2009  

NLE Websites -- All DOE Office Websites (Extended Search)

Helps Discover Helps Discover Cosmic Transients NERSC Helps Discover Cosmic Transients June 15, 2009 M31.png This false-color image of our glowing galactic neighbor, the Andromeda Galaxy, was created by layering 400 individual images captured by the PTF camera in February 2009. In one pointing, the camera has a seven square degree field of view, equivalent to approximately 25 full moons. (Palomar Transient Factory/ Peter Nugent, Berkeley Lab) An innovative new sky survey, called the Palomar Transient Factory (PTF), will utilize the unique tools and services offered by the Department of Energy's (DOE) National Energy Research Scientific Computing Center (NERSC) at the Lawrence Berkeley National Lab (Berkeley Lab) to expose relatively rare and fleeting cosmic events, like supernovae and gamma ray bursts.

394

Cosmological and astrophysical constraints on superconducting cosmic strings  

E-Print Network (OSTI)

We investigate the cosmological and astrophysical constraints on superconducting cosmic strings (SCSs). SCS loops emit strong bursts of electromagnetic waves, which might affect various cosmological and astrophysical observations. We take into account the effect on the CMB anisotropy, CMB blackbody spectrum, BBN, observational implications on radio wave burst and X-ray or gamma-ray events, and stochastic gravitational wave background measured by pulsar timing experiments. We then derive constraints on the parameters of SCS from current observations and estimate prospects for detecting SCS signatures in on-going observations. As a result, we find that these constraints exclude broad parameter regions, and also that on-going radio wave observations can probe large parameter space.

Koichi Miyamoto; Kazunori Nakayama

2012-12-30T23:59:59.000Z

395

Cosmic Growth History and Expansion History  

E-Print Network (OSTI)

The cosmic expansion history tests the dynamics of the global evolution of the universe and its energy density contents, while the cosmic growth history tests the evolution of the inhomogeneous part of the energy density. Precision comparison of the two histories can distinguish the nature of the physics responsible for the accelerating cosmic expansion: an additional smooth component - dark energy - or a modification of the gravitational field equations. With the aid of a new fitting formula for linear perturbation growth accurate to 0.05-0.2%, we separate out the growth dependence on the expansion history and introduce a new growth index parameter \\gamma that quantifies the gravitational modification.

Eric V. Linder

2005-07-11T23:59:59.000Z

396

Cosmic-ray latitude surveys in the Atlantic Ocean area  

Science Conference Proceedings (OSTI)

Vertical cutoff rigidities were re-determined for the locations of the stratospheric balloon measurements made during the 22nd Soviet Antarctic Expedition (1975-1976). These cutoff rigidities were determined for the month of each measurement using a method that interpolates between the world grids of trajectory-derived vertical cutoff rigidities calculated for Epoch 1965.0 and Epoch 1980.0. In comparing these values with other calculated using the 1975.0 field models which under-estimated the secular variations, small increases in the vertical cutoff rigidities were noted in the North Atlantic area and small decreases were noted in the South Atlantic, consistent with the secular changes in the world grid of vertical cutoff rigidities. These results emphasize the necessity of determining cutoff rigidity values of the year in which latitude measurements are made if these measurements are in the region of the world (particularly the Atlantic Ocean area) where the cutoff-rigidity values are rapidly changing.

Shea, M.A.; Smart, D.F.; Stozhkov, Y.I.; Svirzhevsky, N.S.; Svirzhevskaya, A.K.

1987-01-01T23:59:59.000Z

397

Testing hadronic-interaction packages at cosmic-ray energies  

Science Conference Proceedings (OSTI)

A comparative analysis of the secondary particles output of the main hadronic interaction packages used in simulations of extensive air showers is presented. Special attention is given to the study of events with very energetic leading secondary particles, including diffractive interactions.

Canal, C. A. Garcia; Sciutto, S. J. [Departamento de Fisica, Universidad Nacional de La Plata, C.C. 67-1900 La Plata (Argentina); IFLP - CONICET, Universidad Nacional de La Plata, C.C. 67-1900 La Plata (Argentina); Tarutina, T. [Departamento de Fisica, Universidad Nacional de La Plata, C.C. 67-1900 La Plata (Argentina)

2009-03-01T23:59:59.000Z

398

Sneutrino dark matter: Symmetry protection and cosmic ray anomalies  

SciTech Connect

We present an R-parity conserving model of sneutrino dark matter within a Higgsphilic U(1){sup '} extension of the minimal supersymmetric standard model. In this theory, the {mu} parameter and light Dirac neutrino masses are generated naturally upon the breaking of the U(1){sup '} gauge symmetry. One of the right-handed sneutrinos is the lightest supersymmetric particle. The leptonic and hadronic decays of another sneutrino, taken to be the next-to-lightest superpartner, allow for a natural fit to the recent results reported by the PAMELA experiment. We perform a detailed calculation of the dark matter relic density in this scenario, and show that the model is consistent with the ATIC and Fermi LAT experiments.

Demir, Durmus A. [Department of Physics, Izmir Institute of Technology, IZTECH, TR35430 Izmir (Turkey); Everett, Lisa L. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Frank, Mariana [Department of Physics, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B 1R6, (Canada); Selbuz, Levent [Department of Physics, Izmir Institute of Technology, IZTECH, TR35430 Izmir (Turkey); Department of Engineering Physics, Ankara University, TR06100 Ankara (Turkey); Turan, Ismail [Department of Physics, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4B 1R6, (Canada); Ottawa-Carleton Institute of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6. (Canada)

2010-02-01T23:59:59.000Z

399

Testing fundamental principles with high-energy cosmic rays  

E-Print Network (OSTI)

in models incorporating a privileged local reference frame (the "vacuum rest frame", VRF [4, 5 for nucleons, quarks, leptons and the photon [6, 7]. If a VRF exists, LSV can modify the internal structure question is that of the existence of a VRF. Contrary to the old ether, the vacuum of quantum field theory

400

Los Alamos observatory fingers cosmic ray 'hot spots'  

NLE Websites -- All DOE Office Websites (Extended Search)

magnetic fields near our solar system. November 24, 2008 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as...

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401

SLAC National Accelerator Laboratory - Proof: Cosmic Rays Come...  

NLE Websites -- All DOE Office Websites (Extended Search)

in the Feb. 15 issue of Science, the team identified two ancient supernovas whose shock waves accelerated protons to nearly the speed of light, turning them into what we call...

402

Assembly Manual for the Berkeley Lab Cosmic Ray Detector  

E-Print Network (OSTI)

Laboratory Fellowship. This manual is a revised and expandedillustration. Instruction Manual Figure 3: Lucite cookies (effectiveness. Assembly Manual Figure 6: Scintillator end

Collier, Michael

2002-01-01T23:59:59.000Z

403

Gravity's Cosmic ShadowsGravity's Cosmic Shadows A Mathematical UnveilingA Mathematical Unveiling  

E-Print Network (OSTI)

Gravity's Cosmic ShadowsGravity's Cosmic Shadows A Mathematical UnveilingA Mathematical Unveiling of gravity on light SUNSUN #12;Gravitational Lensing - action of gravity on light SUNSUN #12;Gravitational Lensing - action of gravity on light SUNSUN nn 1801: Johann von1801: Johann von SoldnerSoldner (Newtonian

Weinberger, Hans

404

Distant Supernovae and Cosmic Deceleration  

E-Print Network (OSTI)

Distant supernovae can now be detected routinely. To date 34 supernovae at $z > 0.1$ have been discovered. Among them are 12 Type~Ia supernovae confirmed spectroscopically and suited to measure the cosmic deceleration when appropriately employed as standard candles. However, peak magnitudes have been determined for only two objects so far and a determination of $q_0$ is not yet possible. We describe the current status of the searches and possible pitfalls of the method which rests on few basic assumptions. The importance of sufficient information on the distant events is stressed and the observations of SN~1995K are used as an example of the detailed procedures employed in the analysis. Only spectroscopic classification and light curves in at least two filter bands provide the basis to use correction schemes for the luminosity which have successfully been established in nearby samples. Time dilation has been detected acting on the light curve of SN~1995K at a redshift of 0.478, providing clear evidence of universal expansion. The observations are fully consistent with local Type Ia supernovae in an expanding universe but incompatible with the expectations from a static universe. The contributions of the new, large telescopes to this research area are described. The extension of the observations to even more distant objects will provide a better leverage to distinguish between the possible decelerations and the inclusion of Type II supernovae into the sample add an independent check on the cosmological distances.

B. Leibundgut; J. Spyromilio

1996-08-22T23:59:59.000Z

405

Efficiency of Nonlinear Particle Acceleration at Cosmic Structure Shocks  

E-Print Network (OSTI)

We have calculated the evolution of cosmic ray (CR) modified astrophysical shocks for a wide range of shock Mach numbers and shock speeds through numerical simulations of diffusive shock acceleration (DSA) in 1D quasi- parallel plane shocks. The simulations include thermal leakage injection of seed CRs, as well as pre-existing, upstream CR populations. Bohm-like diffusion is assumed. We model shocks similar to those expected around cosmic structure pancakes as well as other accretion shocks driven by flows with upstream gas temperatures in the range $T_0=10^4-10^{7.6}$K and shock Mach numbers spanning $M_s=2.4-133$. We show that CR modified shocks evolve to time-asymptotic states by the time injected particles are accelerated to moderately relativistic energies ($p/mc \\gsim 1$), and that two shocks with the same Mach number, but with different shock speeds, evolve qualitatively similarly when the results are presented in terms of a characteristic diffusion length and diffusion time. For these models the time asymptotic value for the CR acceleration efficiency is controlled mainly by shock Mach number. The modeled high Mach number shocks all evolve towards efficiencies $\\sim 50$%, regardless of the upstream CR pressure. On the other hand, the upstream CR pressure increases the overall CR energy in moderate strength shocks ($M_s \\sim {\\rm a few}$). (abridged)

H. Kang; T. W. Jones

2004-10-29T23:59:59.000Z

406

Fermilab | Science at Fermilab | Experiments & Projects | Cosmic Frontier |  

NLE Websites -- All DOE Office Websites (Extended Search)

Pierre Auger Pierre Auger Pierre Auger Observatory at night Pierre Auger Observatory at night On the pampas of western Argentina, the Pierre Auger cosmic-ray observatory studies the effects of collisions of high-energy particles with Earth's atmosphere over an area of 3,000 square kilometers. When fast-moving particles strike air molecules in the Earth's atmosphere, debris flies from the collision in what is called an air shower. Fragments hit other air molecules in a cascade that continues until the energy of the original particle is spread among millions or even billions of particles raining down on Earth. By studying these air showers, physicists can investigate the source of the original particles. The rate at which particles with energies above 1019 electron volts fall

407

Dark Energy Constraints from the Cosmic Age and Supernova  

E-Print Network (OSTI)

Using the low limit of cosmic ages from globular cluster and the white dwarfs: $t_0 > 12$Gyr, together with recent new high redshift supernova observations from the HST/GOODS program and previous supernova data, we give a considerable estimation of the equation of state for dark energy, with uniform priors as weak as $0.2paper a new scenario of dark energy dubbed Quintom, which gives rise to the equation of state larger than -1 in the past and less than -1 today, satisfying current observations. In addition we've also considered the implications of recent X-ray gas mass fraction data on dark energy, which favors a negative running of the equation of state.

Bo Feng; Xiulian Wang; Xinmin Zhang

2004-04-11T23:59:59.000Z

408

CANGAROO-III SEARCH FOR TeV GAMMA RAYS FROM TWO CLUSTERS OF GALAXIES  

SciTech Connect

Because accretion and merger shocks in clusters of galaxies may accelerate particles to high energies, clusters are candidate sites for the origin of ultra-high-energy (UHE) cosmic rays. A prediction was presented for gamma-ray emission from a cluster of galaxies at a detectable level with the current generation of imaging atmospheric Cherenkov telescopes. The gamma-ray emission was produced via inverse Compton upscattering of cosmic microwave background photons by electron-positron pairs generated by collisions of UHE cosmic rays in the cluster. We observed two clusters of galaxies, Abell 3667 and Abell 4038, searching for very high energy gamma-ray emission with the CANGAROO-III atmospheric Cherenkov telescope system in 2006. The analysis showed no significant excess around these clusters, yielding upper limits on the gamma-ray emission. From a comparison of the upper limit for the northwest radio relic region of Abell 3667 with a model prediction, we derive a lower limit for the magnetic field of the region of approx0.1 muG. This shows the potential of gamma-ray observations in studies of the cluster environment. We also discuss the flux upper limit from cluster center regions using a model of gamma-ray emission from neutral pions produced in hadronic collisions of cosmic-ray protons with the intracluster medium. The derived upper limit of the cosmic-ray energy density within this framework is an order of magnitude higher than that of our Galaxy.

Kiuchi, R.; Mori, M.; Enomoto, R.; Kifune, T. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Bicknell, G. V. [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia); Clay, R. W. [School of Chemistry and Physics, University of Adelaide, SA 5005 (Australia); Edwards, P. G. [CSIRO Australia Telescope National Facility, Narrabri, NSW 2390 (Australia); Gunji, S.; Inoue, K. [Department of Physics, Yamagata University, Yamagata City, Yamagata 990-8560 (Japan); Hara, S.; Itoh, C. [Ibaraki Prefectural University of Health Sciences, Ami, Ibaraki 300-0394 (Japan); Hara, T. [Faculty of Management Information, Yamanashi Gakuin University, Kofu, Yamanashi 400-8575 (Japan); Hattori, T.; Kawachi, A. [Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292 (Japan); Hayashi, S.; Kajino, F. [Department of Physics, Konan University, Kobe, Hyogo 658-8501 (Japan); Higashi, Y.; Kabuki, S. [Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Hirai, Y. [Faculty of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Katagiri, H. [Department of Physical Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

2009-10-10T23:59:59.000Z

409

Hybrid model of GeV-TeV gamma ray emission from Galactic Center  

E-Print Network (OSTI)

The observations of high energy $\\gamma$-ray emission from the Galactic center (GC) by HESS, and recently by Fermi, suggest the cosmic ray acceleration in the GC and possibly around the supermassive black hole. In this work we propose a lepton-hadron hybrid model to explain simultaneously the GeV-TeV $\\gamma$-ray emission. Both electrons and hadronic cosmic rays were accelerated during the past activity of the GC. Then these particles would diffuse outwards and interact with the interstellar gas and background radiation field. The collisions between hadronic cosmic rays with gas is responsible to the TeV $\\gamma$-ray emission detected by HESS. With fast cooling in the strong radiation field, the electrons would cool down and radiate GeV photons through inverse Compton scattering off the soft background photons. This scenario provides a natural explanation of the observed GeV-TeV spectral shape of $\\gamma$-rays.

Yi-Qing Guo; Qiang Yuan; Cheng Liu; Ai-Feng Li

2013-03-26T23:59:59.000Z

410

The Cosmic Electron Background in Low Energy IACTs. Effect of the Geomagnetic Field  

E-Print Network (OSTI)

A new generation of low threshold Imaging Atmospheric Cherenkov Telescopes (IACTs) may reach gamma-ray energies about 10 GeV with high sensitivities and very large collection areas. At these low energies cosmic electrons significantly contribute to the telescope background and are in principle indistinguishable from gamma-rays. In this paper we estimate the electron background expected for two configurations of the low energy IACT MAGIC. We discuss in particular the reduction of the background caused by the geomagnetic field at different locations on the Earth's surface.

J. Cortina; J. C. Gonzalez

2000-10-17T23:59:59.000Z

411

THE SPINE OF THE COSMIC WEB  

Science Conference Proceedings (OSTI)

We present the SpineWeb framework for the topological analysis of the Cosmic Web and the identification of its walls, filaments, and cluster nodes. Based on the watershed segmentation of the cosmic density field, the SpineWeb method invokes the local adjacency properties of the boundaries between the watershed basins to trace the critical points in the density field and the separatrices defined by them. The separatrices are classified into walls and the spine, the network of filaments and nodes in the matter distribution. Testing the method with a heuristic Voronoi model yields outstanding results. Following the discussion of the test results, we apply the SpineWeb method to a set of cosmological N-body simulations. The latter illustrates the potential for studying the structure and dynamics of the Cosmic Web.

Aragon-Calvo, Miguel A.; Szalay, Alexander S. [Johns Hopkins University, 3701 San Martin Drive, Baltimore, MD 21218 (United States); Platen, Erwin; Van de Weygaert, Rien [Kapteyn Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands)

2010-11-01T23:59:59.000Z

412

The Spine of the Cosmic Web  

E-Print Network (OSTI)

We present the SpineWeb framework for the topological analysis of the Cosmic Web and the identification of its walls, filaments and cluster nodes. Based on the watershed segmentation of the cosmic density field, the SpineWeb method invokes the local adjacency properties of the boundaries between the watershed basins to trace the critical points in the density field and the separatrices defined by them. The separatrices are classified into walls and the spine, the network of filaments and nodes in the matter distribution. Testing the method with a heuristic Voronoi model yields outstanding results. Following the discussion of the test results, we apply the SpineWeb method to a set of cosmological N-body simulations. The latter illustrates the potential for studying the structure and dynamics of the Cosmic Web.

Miguel A. Aragon-Calvo; Erwin Platen; Rien van de Weygaert; Alexander S. Szalay

2008-09-30T23:59:59.000Z

413

Cosmic Shear from STIS Pure Parallels: Analysis  

E-Print Network (OSTI)

The measurement of cosmic shear requires deep imaging with high image quality on many lines of sight to sample the statistics of large-scale structure. The expected distortion of galaxy images by cosmic shear on the STIS angular scale is a few percent, therefore the PSF anisotropy has to be understood and controlled to an accuracy better than 1%. In this poster we present the analysis of the PSF of STIS and a preliminary cosmic shear measurement using archival data from the STIS pure parallel program to show that the STIS camera on-board HST is well suited for our project. The data reduction and catalog production are described in an accompanying paper (astro-ph/0102330).

H. Haemmerle; J. -M. Miralles; P. Schneider; T. Erben; R. A. E. Fosbury; W. Freudling; N. Pirzkal; S. D. M. White

2001-09-27T23:59:59.000Z

414

Press Pass - Press Release - U.S. scientists join in "cosmic challenge" at  

NLE Websites -- All DOE Office Websites (Extended Search)

7 7 July 26, 2006 Media Contact: Judy Jackson, Fermilab, 630-840-4112, jjackson@fnal.gov For immediate release U.S. scientists join in "cosmic challenge" at CERN's Large Hadron Collider Batavia, Ill.--Scientists at the Department of Energy's Fermi National Accelerator Laboratory joined collaborators from around the world in announcing today (July 26) that the giant CMS detector at CERN, the European Organization for Nuclear Research, in Geneva, Switzerland, has been sealed and switched on to collect data for an important series of tests using cosmic ray particles. Cosmic rays from space provide a source of high-energy particles like those from accelerator-generated particle collisions. U.S. physicists are among the CMS scientists taking and analyzing data from cosmic rays to calibrate and align the CMS particle detector in preparation for the start-up of the Large Hadron Collider accelerator at CERN next year. DOE's Fermilab, near Chicago, Illinois, serves as the host laboratory for the U.S. CMS collaboration, and the U.S. helped to fund the design and construction of the detector.

415

Cosmic string collision in cosmological backgrounds  

SciTech Connect

The collisions of cosmic string loops and the dynamics of junction formations in expanding backgrounds are studied. The key parameter controlling the dynamics of junction formation, the cosmic strings zipping and unzipping, is the relative size of the loops compared to the Hubble radius at the time of collision. We study analytically and numerically these processes for large superhorizon size loops, for small subhorizon size loops as well as for loops with the radii comparable to the Hubble radius at the time of collision.

Firouzjahi, Hassan [School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Khoeini-Moghaddam, Salomeh [School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Department of Physics, Faculty of Science, Tarbiat Mo'allem University, Tehran (Iran, Islamic Republic of); Khosravi, Shahram [Department of Physics, Faculty of Science, Tarbiat Mo'allem University, Tehran (Iran, Islamic Republic of); School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2010-06-15T23:59:59.000Z

416

A Blind Search for Bursts of Very High Energy Gamma Rays with Milagro.  

E-Print Network (OSTI)

??Milagro is a water-Cherenkov detector that observes the extended air showers produced by cosmic gamma rays of energies E>100GeV. The effective area of Milagro peaks… (more)

Vasileiou, Vlasios

2008-01-01T23:59:59.000Z

417

Determining the jet opening-angle of gamma-ray bursts  

E-Print Network (OSTI)

There is growing scientific agreement that at least some cosmic gamma-ray bursts (GRBs) coincide with the deaths of rapidly rotating massive stars - dubbed "hyper-novae." In 1987, a supernova (SN 1987A) was detected in the ...

McEvoy, Erica Lynn, 1981-

2004-01-01T23:59:59.000Z

418

VHE Gamma-ray Supernova Remnants  

SciTech Connect

Increasing observational evidence gathered especially in X-rays and {gamma}-rays during the course of the last few years support the notion that Supernova remnants (SNRs) are Galactic particle accelerators up to energies close to the ''knee'' in the energy spectrum of Cosmic rays. This review summarizes the current status of {gamma}-ray observations of SNRs. Shell-type as well as plerionic type SNRs are addressed and prospect for observations of these two source classes with the upcoming GLAST satellite in the energy regime above 100 MeV are given.

Funk, Stefan; /KIPAC, Menlo Park

2007-01-22T23:59:59.000Z

419

Gamma-Ray Bursts and Particle Astrophysics  

E-Print Network (OSTI)

Gamma-ray bursts are violent events occurring randomly in the sky. In this review, I will present the fireball model, proposed to explain the phenomenon of gamma-ray bursts. This model has important consequences for the production and observation at Earth of gravitational waves, high energy neutrinos, cosmic rays and high energy photons, and the second part of this review will be focused on these aspects. A last section will briefly discuss the topic of the use of gamma-ray bursts as standard candles and possible cosmological studies.

B. Gendre

2008-07-24T23:59:59.000Z

420

Gamma ray astrophysics: the EGRET results  

E-Print Network (OSTI)

Cosmic gamma rays provide insight into some of the most dynamic processes in the Universe. At the dawn of a new generation of gamma-ray telescopes, this review summarizes results from the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory, the principal predecessor mission studying high-energy photons in the 100 MeV energy range. EGRET viewed a gamma-ray sky dominated by prominent emission from the Milky Way, but featuring an array of other sources, including quasars, pulsars, gamma-ray bursts, and many sources that remain unidentified. A central feature of the EGRET results was the high degree of variability seen in many gamma-ray sources, indicative of the powerful forces at work in objects visible to gamma-ray telescopes.

D J Thompson

2008-11-05T23:59:59.000Z

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421

THE DIFFUSE GAMMA-RAY BACKGROUND FROM TYPE Ia SUPERNOVAE  

SciTech Connect

The origin of the diffuse extragalactic gamma-ray background (EGB) has been intensively studied but remains unsettled. Current popular source candidates include unresolved star-forming galaxies, starburst galaxies, and blazars. In this paper, we calculate the EGB contribution from the interactions of cosmic rays accelerated by Type Ia supernovae (SNe), extending earlier work that only included core-collapse SNe. We consider Type Ia events not only in star-forming galaxies, but also in quiescent galaxies that lack star formation. In the case of star-forming galaxies, consistently including Type Ia events makes little change to the star-forming EGB prediction, so long as both SN types have the same cosmic-ray acceleration efficiencies in star-forming galaxies. Thus, our updated EGB estimate continues to show that star-forming galaxies can represent a substantial portion of the signal measured by Fermi. In the case of quiescent galaxies, conversely, we find a wide range of possibilities for the EGB contribution. The dominant uncertainty we investigated comes from the mass in hot gas in these objects, which provides targets for cosmic rays; total gas masses are as yet poorly known, particularly at larger radii. Additionally, the EGB estimation is very sensitive to the cosmic-ray acceleration efficiency and confinement, especially in quiescent galaxies. In the most optimistic allowed scenarios, quiescent galaxies can be an important source of the EGB. In this case, star-forming galaxies and quiescent galaxies together will dominate the EGB and leave little room for other contributions. If other sources, such as blazars, are found to have important contributions to the EGB, then either the gas mass or cosmic-ray content of quiescent galaxies must be significantly lower than in their star-forming counterparts. In any case, improved Fermi EGB measurements will provide important constraints on hot gas and cosmic rays in quiescent galaxies.

Lien, Amy; Fields, Brian D. [Department of Physics, University of Illinois, Urbana, IL 61801 (United States)

2012-03-10T23:59:59.000Z

422

Viscous Modified Cosmic Chaplygin Gas Cosmology  

E-Print Network (OSTI)

In this paper we construct modified cosmic Chaplygin gas which has viscosity. We use exponential function method to solve non-linear equation and obtain time-dependent dark energy density. Then discuss Hubble expansion parameter and scale factor and fix them by using observational data. We also investigate stability of this theory.

Behnam Pourhassan

2013-01-13T23:59:59.000Z

423

Production of Axions by Cosmic Magnetic Helicity  

E-Print Network (OSTI)

We investigate the effects of an external magnetic helicity production on the evolution of the cosmic axion field. It is shown that a helicity larger than (few \\times 10^{-15} G)^2 Mpc, if produced at temperatures above a few GeV, is in contradiction with the existence of the axion, since it would produce too much of an axion relic abundance.

L. Campanelli; M. Giannotti

2005-12-17T23:59:59.000Z

424

Zipping and Unzipping of Cosmic String Loops in Collision  

E-Print Network (OSTI)

In this paper the collision of two cosmic string loops is studied. After collision junctions are formed and the loops are entangled. We show that after their formation the junctions start to unzip and the loops disentangle. This analysis provides a theoretical understanding of the unzipping effect observed in numerical simulations of a network of cosmic strings with more than one type of cosmic strings. The unzipping phenomena have important effects in the evolution of cosmic string networks when junctions are formed upon collision, such as in a network of cosmic superstrings.

Hassan Firouzjahi; Johanna Karouby; Shahram Khosravi; Robert Brandenberger

2009-07-28T23:59:59.000Z

425

Kaluza-Klein and Gauss-Bonnet cosmic strings  

E-Print Network (OSTI)

We make a systematic investigation of stationary cylindrically symmetric solutions to the five-dimensional Einstein and Einstein-Gauss-Bonnet equations. Apart from the five-dimensional neutral cosmic string metric, we find two new exact solutions which qualify as cosmic strings, one corresponding to an electrically charged cosmic string, the other to an extended superconducting cosmic string surrounding a charged core. In both cases, test particles are deflected away from the singular line source. We extend both kinds of solutions to exact multi-cosmic string solutions.

Mustapha Azreg-Ainou; Gérard Clément

1996-03-29T23:59:59.000Z

426

STATEMENT OF CONSIDERATIONS REQUEST BY FORD MOTOR COMPANY FOR AN ADVANCE WAIVER OF IOMES'I'I AND FORKIGN PAT'INT KIGHITS  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

NOV. -21' 94(MON) 14:27 DOE-IP IICAGO TEL1 708 2 779 P, 002 NOV. -21' 94(MON) 14:27 DOE-IP IICAGO TEL1 708 2 779 P, 002 STATEMENT OF CONSIDERATIONS REQUEST BY FORD MOTOR COMPANY FOR AN ADVANCE WAIVER OF IOMES'I'I AND FORKIGN PAT'INT KIGHITS UNDER DOE CONTRACT NO: DE-AC02-94CE50389; W(A)-94-027; CH-842 AND FOR LARGE BUSINESS LOWER TIER SUBCONTRACTS THEREUNDER The Ford Motor Company has petitioned ihe DOE for an advance waiver of paltent lights, both domestic and foreign, for all subject inventions arising under the above identified contract and under all lower tier subcontracts entered into thereunder with parties other than domestic small businesses, nonprofit organizations and universities, and National Laboratories. The purpose of the agreement is to conduct research and development to advance proton-cxchange-

427