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1

Modification of laminar flow ultrafine condensation particle counters for the enhanced detection of 1 nm condensation nuclei  

SciTech Connect

This paper describes simple modifications to thermally diffusive laminar flow ultrafine condensation particle counters (UCPCs) that allow detection of {approx}1 nm condensation nuclei with much higher efficiencies than have been previously reported. These nondestructive modifications were applied to a commercial butanol based UCPC (TSI 3025A) and to a diethylene glycol-based UCPC (UMN DEG-UCPC). Size and charge dependent detection efficiencies using the modified UCPCs (BNL 3025A and BNL DEGUCPC) were measured with high resolution mobility classified aerosols composed of NaCl, W, molecular ion standards of tetraalkyl ammonium bromide, and neutralizer-generated ions. With negatively charged NaCl aerosol, the BNL 3025A and BNL DEGUCPC achieved detection efficiencies of 37% (90x increase over TSI 3025A) at 1.68 nm mobility diameter (1.39 nm geometric diameter) and 23% (8x increase over UMN DEG-UCPC) at 1.19 nm mobility diameter (0.89 nm geometric diameter), respectively. Operating conditions for both UCPCs were identified that allowed negatively charged NaCl and W particles, but not negative ions of exactly the same mobility size, to be efficiently detected. This serendipitous material dependence, which is not fundamentally understood, suggests that vapor condensation might sometimes allow for the discrimination between air 'ions' and charged 'particles.' As a detector in a scanning mobility particle spectrometer (SMPS), a UCPC with this strong material dependence would allow for more accurate measurements of sub-2 nm aerosol size distributions due to the reduced interference from neutralizer-generated ions and atmospheric ions, and provide increased sensitivity for the determination of nucleation rates and initial particle growth rates.

Kuang, C.; Chen, M.; McMurry, P. H.; Wang, J.

2011-10-01T23:59:59.000Z

2

Counter Rotating Open Rotor Animation using Particle Image Velocimetry  

E-Print Network (OSTI)

This article describes the two accompanying fluid dynamics videos for the "Counter rotating open rotor flow field investigation using stereoscopic Particle Image Velocimetry" presented at the 64th Annual Meeting of the APS Division of Fluid Dynamics in Baltimore, Maryland, November 20-22, 2011.

Roosenboom, E W M; Geisler, R; Pallek, D; Agocs, J; Neitzke, K -P

2011-01-01T23:59:59.000Z

3

Modification of a Commercial Condensation Particle Counter for Boundary Layer Balloon-Borne Aerosol Studies  

Science Conference Proceedings (OSTI)

A commercial battery-driven condensation particle counter (TSI-8020) was modified for use in a lightweight payload for tethered balloons to study new particle formation in the planetary boundary layer. After modifications, the instrument was ...

Jost Heintzenberg; Alfred Wiedensohler; Stefan Kütz

1999-05-01T23:59:59.000Z

4

Coincidence and Dead-Time Corrections for Particle Counters. Part I: A General Mathematical Formalism  

Science Conference Proceedings (OSTI)

Counting loss due to coincidences limit the efficiency of the retriggerable particle counters. When the particle rate increases, the counted rate rapidly reaches a maximum so that it becomes impossible to precisely estimate the actual value. On ...

J. L. Brenguier; L. Amodei

1989-08-01T23:59:59.000Z

5

Electrical Mobility Spectrometer Using a Diethylene Glycol Condensation Particle Counter for Measurement of Aerosol Size Distributions Down to 1 nm  

Science Conference Proceedings (OSTI)

We report a new scanning mobility particle spectrometer (SMPS) for measuring number size distributions of particles down to {approx}1 nm mobility diameter. This SMPS includes an aerosol charger, a TSI 3085 nano differential mobility analyzer (nanoDMA), an ultrafine condensation particle counter (UCPC) using diethylene glycol (DEG) as the working fluid, and a conventional butanol CPC (the 'booster') to detect the small droplets leaving the DEG UCPC. The response of the DEG UCPC to negatively charged sodium chloride particles with mobility diameters ranging from 1-6 nm was measured. The sensitivity of the DEG UCPC to particle composition was also studied by comparing its response to positively charged 1.47 and 1.70 nm tetra-alkyl ammonium ions, sodium chloride, and silver particles. A high resolution differential mobility analyzer was used to generate the test particles. These results show that the response of this UCPC to sub-2 nm particles is sensitive to particle composition. The applicability of the new SMPS for atmospheric measurement was demonstrated during the Nucleation and Cloud Condensation Nuclei (NCCN) field campaign (Atlanta, Georgia, summer 2009). We operated the instrument at saturator and condenser temperatures that allowed the efficient detection of sodium chloride particles but not of air ions having the same mobility. We found that particles as small as 1 nm were detected during nucleation events but not at other times. Factors affecting size distribution measurements, including aerosol charging in the 1-10 nm size range, are discussed. For the charger used in this study, bipolar charging was found to be more effective for sub-2 nm particles than unipolar charging. No ion induced nucleation inside the charger was observed during the NCCN campaign.

Jiang, J.; Kuang, C.; Chen, M.; Attoui, M.; McMurry, P. H.

2011-02-01T23:59:59.000Z

6

Development of position sensitive proportional counters for hot particle detection in laundry and portal monitors  

SciTech Connect

This report summarizes research which demonstrates the use of position sensitive proportional counters in contamination monitoring systems. Both laundry monitoring and portal monitoring systems were developed. The laundry monitor was deployed at a nuclear power plant where it was used to monitor clothing during an outage. Position sensitive proportional counter based contamination monitoring systems were shown to have significant advantages over systems using conventional proportional counters. These advantages include the ability to directly measure the area and quantity of contamination. This capability permits identification of hot particles. These systems are also capable of self calibration via internal check sources. Systems deployed with this technology should benefit from reduced complexity, cost and maintenance. The inherent reduction of background that occurs when the counter is electronically divided into numerous detectors permits operation in high background radiation fields and improves detection limits over conventional technology.

Shonka, J.J.; Schwahn, S.O.; Bennett, T.E.; Misko, D.J. (Shonka Research Associates, Inc., Marietta, GA (United States))

1992-09-01T23:59:59.000Z

7

Ice Nuclei in Marine Air: Biogenic Particles or Dust?  

Science Conference Proceedings (OSTI)

Ice nuclei impact clouds, but their sources and distribution in the atmosphere are still not well known. Particularly little attention has been paid to IN sources in marine environments, although evidence from field studies suggests that IN populations in remote marine regions may be dominated by primary biogenic particles associated with sea spray. In this exploratory model study, we aim to bring attention to this long-neglected topic and identify promising target regions for future field campaigns. We assess the likely global distribution of marine biogenic ice nuclei using a combination of historical observations, satellite data and model output. By comparing simulated marine biogenic immersion IN distributions and dust immersion IN distributions, we predict strong regional differences in the importance of marine biogenic IN relative to dust IN. Our analysis suggests that marine biogenic IN are most likely to play a dominant role in determining IN concentrations in near-surface-air over the Southern Ocean, so future field campaigns aimed at investigating marine biogenic IN should target that region. Climate related changes in the abundance and emission of biogenic marine IN could affect marine cloud properties, thereby introducing previously unconsidered feedbacks that influence the hydrological cycle and the Earth’s energy balance. Furthermore, marine biogenic IN may be an important aspect to consider in proposals for marine cloud brightening by artificial sea spray production.

Burrows, Susannah M.; Hoose, C.; Poschl, U.; Lawrence, M.

2013-01-11T23:59:59.000Z

8

Cherenkov Counters  

SciTech Connect

When a charged particle passes through an optically transparent medium with a velocity greater than the phase velocity of light in that medium, it emits prompt photons, called Cherenkov radiation, at a characteristic polar angle that depends on the particle velocity. Cherenkov counters are particle detectors that make use of this radiation. Uses include prompt particle counting, the detection of fast particles, the measurement of particle masses, and the tracking or localization of events in very large, natural radiators such as the atmosphere, or natural ice fields, like those at the South Pole in Antarctica. Cherenkov counters are used in a number of different fields, including high energy and nuclear physics detectors at particle accelerators, in nuclear reactors, cosmic ray detectors, particle astrophysics detectors and neutrino astronomy, and in biomedicine for labeling certain biological molecules.

Barbero, Marlon

2012-04-19T23:59:59.000Z

9

Multi-particle correlation function to study short-lived nuclei  

E-Print Network (OSTI)

Unstable 10C nuclei are produced as quasi-projectiles in 12C+24Mg collisions at E/A = 53 and 95 MeV. The decay of their short-lived states is studied with the INDRA multidetector array via multi-particle correlation functions. The obtained results show that heavy-ion collisions can be used as a tool to access spectroscopic information of unbound states in exotic nuclei, such as their energies and the relative importance of different sequential decay widths.

Grenier, F; Roy, R; Verde, G; Thériault, D; Frankland, J D; Wieleczko, J P; Borderie, B; Bougault, R; Dayras, R; Galíchet, E; Guinet, D; Lautesse, P; Neindre, N Le; López, O; Moisan, J; Nalpas, L; Napolitani, P; Pârlog, M; Rivet, M F; Rosato, E; Tamain, B; Vient, E; Vigilante, M

2008-01-01T23:59:59.000Z

10

Multi-particle correlation function to study short-lived nuclei  

E-Print Network (OSTI)

Unstable 10C nuclei are produced as quasi-projectiles in 12C+24Mg collisions at E/A = 53 and 95 MeV. The decay of their short-lived states is studied with the INDRA multidetector array via multi-particle correlation functions. The obtained results show that heavy-ion collisions can be used as a tool to access spectroscopic information of unbound states in exotic nuclei, such as their energies and the relative importance of different sequential decay widths.

F. Grenier; A. Chbihi; R. Roy; G. Verde; D. Thériault; J. D. Frankland; J. P. Wieleczko; B. Borderie; R. Bougault; R. Dayras; E. Galichet; D. Guinet; P. Lautesse; N. Le Neindre; O. Lopez; J. Moisan; L. Nalpas; P. Napolitani; M. Parlog; M. F. Rivet; E. Rosato; B. Tamain; E. Vient; M. Vigilante

2008-10-08T23:59:59.000Z

11

Effects of particle-number conservation on heat capacity of nuclei  

E-Print Network (OSTI)

By applying the particle-number projection to the finite-temperature BCS theory, the $S$-shaped heat capacity, which has recently been claimed to be a fingerprint of the superfluid-to-normal phase transition in nuclei, is reexamined. It is found that the particle-number (or number-parity) projection gives $S$-shapes in the heat capacity of nuclei which look qualitatively similar to the observed ones. These $S$-shapes are accounted for as effects of the particle-number conservation on the quasiparticle excitations, and occur even when we keep the superfluidity at all temperatures by assuming a constant gap in the BCS theory. The present study illustrates significance of the conservation laws in studying phase transitions of finite systems.

K. Esashika; H. Nakada; K. Tanabe

2005-03-28T23:59:59.000Z

12

ARM - Measurement - Cloud condensation nuclei  

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

condensation nuclei condensation nuclei ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud condensation nuclei Small particles (typically 0.0002 mm, or 1/100 th the size of a cloud droplet) about which cloud droplets coalesce. Categories Aerosols, Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments AOS : Aerosol Observing System CCN : Cloud Condensation Nuclei Particle Counter Field Campaign Instruments AOS : Aerosol Observing System

13

AUTOMATIC COUNTER  

DOE Patents (OSTI)

An automatic counter of alpha particle tracks recorded by a sensitive emulsion of a photographic plate is described. The counter includes a source of mcdulated dark-field illumination for developing light flashes from the recorded particle tracks as the photographic plate is automatically scanned in narrow strips. Photoelectric means convert the light flashes to proportional current pulses for application to an electronic counting circuit. Photoelectric means are further provided for developing a phase reference signal from the photographic plate in such a manner that signals arising from particle tracks not parallel to the edge of the plate are out of phase with the reference signal. The counting circuit includes provision for rejecting the out-of-phase signals resulting from unoriented tracks as well as signals resulting from spurious marks on the plate such as scratches, dust or grain clumpings, etc. The output of the circuit is hence indicative only of the tracks that would be counted by a human operator.

Robinson, H.P.

1960-06-01T23:59:59.000Z

14

A Miniature Optical Particle Counter for In Situ Aircraft Aerosol Research  

Science Conference Proceedings (OSTI)

Modification of a commercial Met One 237A optical sensor to accept custom electronics consisting of a single logarithmic amplifier providing 256 size bins over the 0.3–14-?m diameter range is described. Configuration of the optical particle ...

Antony D. Clarke; Norman C. Ahlquist; Steven Howell; Ken Moore

2002-10-01T23:59:59.000Z

15

Air Proportional Counter  

DOE Patents (OSTI)

A multiple wire counter utilizing air at atmospheric pressure as the ionizing medium and having a window of a nylon sheet of less than 0.5 mil thickness coated with graphite. The window is permeable to alpha particles so that the counter is well adapted to surveying sources of alpha radiation.

Simpson, J.A. Jr.

1950-10-31T23:59:59.000Z

16

GASEOUS SCINTILLATION COUNTER  

DOE Patents (OSTI)

A gaseous excitation counter for detecting the presence amd measuring the energy of subatomic particles and electromagnetic radiation is described. The counter includes a gas-tight chamber filled with an elemental gas capable of producing ultra-violet excitation quanta when irradiated with subatomic particles and electromagnetic radiation. The gas has less than one in a thousand parts ultra-violet absorbing contamination. When nuclear radiation ps present the ultra-violet light produced by the gas strikes a fluorescent material within the counter, responsive to produce visible excitation quanta, and photo-sensitive counting means detect the visible emission.

Eggler, C.; Huddleston, C.M.

1959-04-28T23:59:59.000Z

17

Workshop on nuclear chromodynamics: Quarks and gluons in particles and nuclei  

SciTech Connect

The assertion that quantum chromodynamics (QCD) is the correct theory describing strong interaction phenomena has, largely by repetition, become rather non-controversial. It is likely even true. However, whether or not it is correct in detail, the experimentally supported realization that colored quarks and gluons are the elementary degrees of freedom, that asymptotic freedom makes short distance phenomena rather ''simple'' to understand, and that color is confined on the hadronic length scale of -- 1 fm has led to a profound change in the character of our attempts to understand the structure and interactions of both hadrons and nuclei. Many of the most important issued in particle physics and in nuclear physics are now seen to be intimately connected. An understanding of the validity and limits of effective theories based upon hadron degrees of freedom, so phenomenologically successful in describing a host of low energy phenomena, is coming into focus. The existence of new forms of matter grounded in the hidden color degree of freedom is predicted. These considerations form the subject of nuclear chromodynamics (NCD). The subject is far from mature and is developing rapidly.

Brodsky, S.; Moniz, E.

1985-01-01T23:59:59.000Z

18

Compact fission counter for DANCE  

SciTech Connect

The Detector for Advanced Neutron Capture Experiments (DANCE) consists of 160 BF{sub 2} crystals with equal solid-angle coverage. DANCE is a 4{pi} {gamma}-ray calorimeter and designed to study the neutron-capture reactions on small quantities of radioactive and rare stable nuclei. These reactions are important for the radiochemistry applications and modeling the element production in stars. The recognition of capture event is made by the summed {gamma}-ray energy which is equivalent of the reaction Q-value and unique for a given capture reaction. For a selective group of actinides, where the neutron-induced fission reaction competes favorably with the neutron capture reaction, additional signature is needed to distinguish between fission and capture {gamma} rays for the DANCE measurement. This can be accomplished by introducing a detector system to tag fission fragments and thus establish a unique signature for the fission event. Once this system is implemented, one has the opportunity to study not only the capture but also fission reactions. A parallel-plate avalanche counter (PPAC) has many advantages for the detection of heavy charged particles such as fission fragments. These include fast timing, resistance to radiation damage, and tolerance of high counting rate. A PPAC also can be tuned to be insensitive to {alpha} particles, which is important for experiments with {alpha}-emitting actinides. Therefore, a PPAC is an ideal detector for experiments requiring a fast and clean trigger for fission. A PPAC with an ingenious design was fabricated in 2006 by integrating amplifiers into the target assembly. However, this counter was proved to be unsuitable for this application because of issues related to the stability of amplifiers and the ability to separate fission fragments from {alpha}'s. Therefore, a new design is needed. A LLNL proposal to develop a new PPAC for DANCE was funded by NA22 in FY09. The design goal is to minimize the mass for the proposed counter and still be able to maintain a stable operation under extreme radioactivity and the ability to separate fission fragments from {alpha}'s. In the following sections, the description is given for the design and performance of this new compact PPAC, for studying the neutron-induced reactions on actinides using DANCE at LANL.

Wu, C Y; Chyzh, A; Kwan, E; Henderson, R; Gostic, J; Carter, D; Bredeweg, T; Couture, A; Jandel, M; Ullmann, J

2010-11-06T23:59:59.000Z

19

Charged Particle Capture Reaction Measurements Related to P-Nuclei: The Present Status and Outlook  

Science Conference Proceedings (OSTI)

A short overview and the present status of charged particle capture reaction measurements by activation method related to p-process are given here.

Oezkan, Nalan [Kocaeli University, Department of Physics, TR-41380 Umuttepe, Kocaeli (Turkey)

2008-11-11T23:59:59.000Z

20

Competition between Sea Salt and Sulfate Particles as Cloud Condensation Nuclei  

Science Conference Proceedings (OSTI)

The influence of sea salt on the cloud droplet activation of sulfate particles is investigated using a size-resolving model of the aerosol activation process. The authors found that the total number concentration of activated cloud droplets ...

Steven J. Ghan; Gina Guzman; Hayder Abdul-Razzak

1998-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

Impact of new particle formation on the concentrations of aerosol number and cloud condensation nuclei around Beijing  

Science Conference Proceedings (OSTI)

New particle formation (NPF) is one of the most important processes in controlling the concentrations of aerosol number (condensation nuclei, CN) and cloud condensation nuclei (CCN) in the atmosphere. In this study, we introduced a new aerosol model representation with 20 size bins between 1 nm and 10 {mu}m and activation-type and kinetic nucleation parameterizations into the WRF-chem model (called NPF-explicit WRF-chem). Model calculations were conducted in the Beijing region in China for the periods during the CARE-Beijing 2006 campaign conducted in August and September 2006. Model calculations successfully reproduced the timing of NPF and no-NPF days in the measurements (21 of 26 days). Model calculations also reproduced the subsequent rapid growth of new particles with a time scale of half a day. These results suggest that once a reasonable nucleation rate at a diameter of 1 nm is given, explicit calculations of condensation and coagulation processes can reproduce the clear contrast between NPF and no-NPF days as well as further growth up to several tens nanometers. With this reasonable representation of the NPF process, we show that NPF contributed 20-30% of CN concentrations (> 10 nm in diameter) in and around Beijing on average. We also show that NPF increases CCN concentrations at higher supersaturations (S > 0.2%), while it decreases them at lower supersaturations (S aerosol emissions, such as black carbon (BC), would not necessarily decrease CCN concentrations because of an increase in NPF. Sensitivity calculations also suggest that the reduction ratio of primary aerosol and SO2 emissions will be key in enhancing or damping the BC mitigation effect.

Matsui, H.; Koike, Makoto; Kondo, Yutaka; Takegawa, Nobuyuki; Wiedensohler, A.; Fast, Jerome D.; Zaveri, Rahul A.

2011-10-13T23:59:59.000Z

22

RADIATION COUNTER  

DOE Patents (OSTI)

This patent relates to a radiation counter, and more particularly, to a scintillation counter having high uniform sensitivity over a wide area and capable of measuring alpha, beta, and gamma contamination over wide energy ranges, for use in quickly checking the contami-nation of personnel. Several photomultiplier tubes are disposed in parallel relationship with a light tight housing behind a wall of scintillation material. Mounted within the housing with the photomultipliers are circuit means for producing an audible sound for each pulse detected, and a range selector developing a voltage proportional to the repetition rate of the detected pulses and automatically altering its time constant when the voltage reaches a predetermined value, so that manual range adjustment of associated metering means is not required.

Goldsworthy, W.W.

1958-02-01T23:59:59.000Z

23

ARM - Measurement - Ice nuclei  

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

to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Ice nuclei Small particles around which ice particles form. Categories Cloud Properties...

24

Channel coupling and exchange of an alpha-particle cluster in deuteron scattering on {sup 6}Li nuclei  

SciTech Connect

Existing experimental data on elastic and inelastic deuteron scattering on {sup 6}Li nuclei in the energy range from 8 to 50 MeV were analyzed within the approach of coupled reaction channels. The coupling of elastic scattering and inelastic scattering accompanied by the transition to the 3{sup +} state at E{sub x} 2.186 MeV and the mechanism involving the exchange of an alpha-particle cluster were taken into account in respective calculations. The phenomenological potentials obtained from the present analysis describe well experimental angular distributions at all energies and in full angular ranges. The depths of the real and imaginary parts of the potentials in question depend smoothly on energy at fixed values of the remaining parameters. The energy dependence of relevant volume integrals agrees well with similar data for the p + {sup 6}Li, {alpha} + {sup 6}Li, and {sup 12}C + {sup 12}C systems and with the predictions of a microscopic theory.

Sakuta, S. B., E-mail: sakuta@dni.polyn.kiae.su [Russian Research Centre Kurchatov Institute (Russian Federation); Burtebaev, N. [National Nuclear Center of the Republic Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Artemov, S. V.; Yarmukhamedov, R. [National Nuclear Center of the Republic Uzbekistan, Institute of Nuclear Physics (Uzbekistan)

2012-07-15T23:59:59.000Z

25

Cloud Condensation Nuclei  

Science Conference Proceedings (OSTI)

The state of knowledge of the particles upon which liquid droplets condense to form atmospheric water clouds is presented. The realization of cloud condensation nuclei (CCN) as a distinct aerosol subset originated with the cloud microphysical ...

James G. Hudson

1993-04-01T23:59:59.000Z

26

Master Thesis Ring Imaging Cerenkov Counter with Aerogel  

E-Print Network (OSTI)

[a4]report #12; i Master Thesis Ring Imaging Cerenkov Counter with Aerogel Radiator for HERMES-inlusive spin asymmetries. In the past, HERMES used a threshold Cerenkov counter as one of its four particle the threshold Cerenkov counter with a Ring Imaging Cerenkov system(RICH) in 1998, so that it can separate #25

27

Particle-resolved simulation of aerosol size, composition, mixing state, and the associated optical and cloud condensation nuclei activation properties in an evolving urban plume  

SciTech Connect

The recently developed particle-resolved aerosol box model PartMC-MOSAIC was used to simulate the evolution of aerosol mixing state and the associated optical and cloud condensation nuclei (CCN) activation properties in an idealized urban plume. The model explicitly resolved the size and composition of individual particles from a number of sources and tracked their evolution due to condensation/evaporation, coagulation, emission, and dilution. The ensemble black carbon (BC) specific absorption cross section increased by 40% over the course of two days as a result of BC aging by condensation and coagulation. Three- and four-fold enhancements in CCN/CN ratios were predicted to occur within 6 hours for 0.2% and 0.5% supersaturations (S), respectively. The particle-resolved results were used to evaluate the errors in the optical and CCN activation properties that would be predicted by a conventional sectional framework that assumes monodisperse, internally-mixed particles within each bin. This assumption artificially increased the ensemble BC specific absorption by 14-30% and decreased the single scattering albedo by 0.03-0.07 while the bin resolution had a negligible effect. In contrast, the errors in CCN/CN ratios were sensitive to the bin resolution, and they depended on the chosen supersaturation. For S = 0.2%, the CCN/CN ratio predicted using 100 internally-mixed bins was up to 25% higher than the particle-resolved results, while it was up to 125% higher using 10 internally-mixed bins. Errors introduced in the predicted optical and CCN properties by neglecting coagulation were also quantified.

Zaveri, Rahul A.; Barnard, James C.; Easter, Richard C.; Riemer, Nicole; West, Matthew

2010-09-11T23:59:59.000Z

28

Density-induced suppression of the alpha-particle condensate in nuclear matter and the structure of alpha cluster states in nuclei  

E-Print Network (OSTI)

At low densities, with decreasing temperatures, in symmetric nuclear matter alpha-particles are formed, which eventually give raise to a quantum condensate with four-nucleon alpha-like correlations (quartetting). Starting with a model of alpha-matter, where undistorted alpha particles interact via an effective interaction such as the Ali-Bodmer potential, the suppression of the condensate fraction at zero temperature with increasing density is considered. Using a Jastrow-Feenberg approach, it is found that the condensate fraction vanishes near saturation density. Additionally, the modification of the internal state of the alpha particle due to medium effects will further reduce the condensate. In finite systems, an enhancement of the S state wave function of the c.o.m. orbital of alpha particle motion is considered as the correspondence to the condensate. Wave functions have been constructed for self-conjugate 4n nuclei which describe the condensate state, but are fully antisymmetrized on the nucleonic level. These condensate-like cluster wave functions have been successfully applied to describe properties of low-density states near the n alpha threshold. Comparison with OCM calculations in 12C and 16O shows strong enhancement of the occupation of the S-state c.o.m. orbital of the alpha-particles. This enhancement is decreasing if the baryon density increases, similar to the density-induced suppression of the condensate fraction in alpha matter. The ground states of 12C and 16O show no enhancement at all, thus a quartetting condensate cannot be formed at saturation densities.

Y. Funaki; H. Horiuchi; G. Röpke; P. Schuck; A. Tohsaki; T. Yamada

2008-01-21T23:59:59.000Z

29

Pyrochemical multiplicity counter development  

Science Conference Proceedings (OSTI)

Impure plutonium-bearing materials from pyrochemical processes often display both significant self-multiplication and variable ({alpha},n) reaction rates. Standard neutron coincidence counting techniques usually fail to accurately measure these materials. Neutron multiplicity counters measure the third moment of the neutron multiplicity distribution and thus make it possible to deduce the fertile plutonium mass of a sample even when both the self-multiplication and the ({alpha},n) reaction rate are unknown. A multiplicity counter suitable for measuring pyrochemical materials has been designed and built. This paper describes the results of characterization studies for the new counter. The counter consists of 126 helium-3 tubes arranged in 4 concentric rings in a polyethylene moderator; the average spacing between the tubes is 1.59 cm. The end plugs for the counter are made of graphite, and the 24.1- by 37.5-cm sample cavity is cadmium lined. The counter consists of two distinct halves from which the neutron counts are summed. The counter is capable of operation in either a freestanding mode with the two halves coupled together by an external cabinet or in a glove-box mode with the two halves placed around a glovebox well and then mated. For a {sup 252}Cf source centered in the sample cavity, the measured efficiency of the new multiplicity counter is 57.7% and its die-away time is 47.2{mu}s. 8 refs., 9 figs.

Langner, D.G.; Dytlewski, N.; Krick, M.S.

1991-01-01T23:59:59.000Z

30

Effects of T-odd asymmetry of the emission of light charged particles and photons during fission of heavy nuclei by polarized neutrons  

Science Conference Proceedings (OSTI)

The new physical effects of T-odd asymmetry of the emission of light charged particles (LCPs) during the ternary fission of some heavy nuclei by cold polarized neutrons have been experimentally studied. The coefficients of triple scalar and vector correlation of the pulses of light particles and fission fragments (TRI effect) and the fivefold correlation of the same vectors (ROT effect) have been measured. These effects are believed to be caused by the rotation of polarized fissioning system around its polarization direction. The treatment of the experimental data for LCPs in the framework of this hypothesis leads to a good agreement between the calculation results and experimental data. The calculated value of the angle of rotation of the fission axis in the ternary fission of the polarized fissioning {sup 236}U* compound nucleus was used to process the results of measuring the ROT effect for {gamma} photons from binary-fission fragments of the same nucleus. A satisfactory description of these experimental data is obtained which serves a convincing confirmation of the rotation hypothesis.

Gagarskii, A. M.; Guseva, I. S. [Russian Academy of Sciences, St. Petersburg Nuclear Physics Institute (Russian Federation); Goennenwein, F. [Technische Universitat (Germany); Kopach, Yu. N. [Joint Institute for Nuclear Research (Russian Federation); Mutterer, M. [Eberhard Karls Universitat Tubingen (Germany); Kuz'mina, T. E. [Khlopin Radium Institute (Russian Federation); Petrov, G. A., E-mail: gpetrov@pnpi.spb.ru [Russian Academy of Sciences, St. Petersburg Nuclear Physics Institute (Russian Federation); Tyurin, G. [Khlopin Radium Institute (Russian Federation); Nesvizhevsky, V. [Institut Laue-Langevin (France)

2011-12-15T23:59:59.000Z

31

Portable multiplicity counter  

DOE Patents (OSTI)

A portable multiplicity counter has signal input circuitry, processing circuitry and a user/computer interface disposed in a housing. The processing circuitry, which can comprise a microcontroller integrated circuit operably coupled to shift register circuitry implemented in a field programmable gate array, is configured to be operable via the user/computer interface to count input signal pluses receivable at said signal input circuitry and record time correlations thereof in a total counting mode, coincidence counting mode and/or a multiplicity counting mode. The user/computer interface can be for example an LCD display/keypad and/or a USB interface. The counter can include a battery pack for powering the counter and low/high voltage power supplies for biasing external detectors so that the counter can be configured as a hand-held device for counting neutron events.

Newell, Matthew R. (Los Alamos, NM); Jones, David Carl (Los Alamos, NM)

2009-09-01T23:59:59.000Z

32

Counter Current Multiplier Mechanism  

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

Counter Current Multiplier Mechanism Counter Current Multiplier Mechanism Name: Stephen Location: N/A Country: N/A Date: N/A Question: Can you please explain to me the counter-current multiplier mechanism. I understand that cholride and sodium ions are filtered out of the ascending loop of Henle into the interstial fluid, however, I'm not sure exactly what happens from there and how this effects osmotic pressure gradients in the nephron. Any help would be greatly appriciated. Replies: This mechanism is very complex when it comes to writing a response. You have to have a strong background in osmotic pressure understanding and the anatomy of the kidney. It involves the cortex, outer and inner medula in relationship to the vasa recta, interstitial fluids at two points, the loop of Henle and the collecting duct. The size of the tubes and the position in relations to the cortex and medulla is an essential part. I can suggest some references.

33

Compressor surge counter  

DOE Patents (OSTI)

A surge counter for a rotating compressor is provided which detects surging by monitoring the vibration signal from an accelerometer mounted on the shaft bearing of the compressor. The circuit detects a rapid increase in the amplitude envelope of the vibration signal, e.g., 4 dB or greater in less than one second, which is associated with a surge onset and increments a counter. The circuit is rendered non-responsive for a period of about 5 seconds following the detection which corresponds to the duration of the surge condition. This prevents multiple registration of counts during the surge period due to rapid swings in vibration amplitude during the period.

Castleberry, Kimberly N. (Harriman, TN)

1983-01-01T23:59:59.000Z

34

Atmospheric Concentrations of Submicron Contact-freezing Nuclei  

Science Conference Proceedings (OSTI)

Atmospheric concentrations of contact-freezing nuclei were measured using a technique primarily sensitive to submicron aerosol particles. Diffusion and phoretic forces were relied on for the capture of nuclei by supercooled drops of distilled ...

Terry Deshler; Gabor Vali

1992-05-01T23:59:59.000Z

35

A Liquid-Hydrogen Cerenkov Counter  

DOE Green Energy (OSTI)

Two models of a liquid-hydrogen (?-illegible) Cherenkov counter (illegible) been constructed (illegible). The first served as a prototype (?-illegible) and was (illegible) to demonstrate the feasibility (?-illegible) of the (illegible) concept (?-illegible) (illegible) liquid hydrogen does not give scintillation (?-illegible) (illegible) that of Cherenkov light. The second, final version (?-illegible), (illegible) in an experiment (?-illegible) in which particles brought to rest (?-illegible) (illegible) (illegible) electrons. In this second counter, the efficiency (?-illegible) (illegible) relativistic (?-illegible) particles (?-illegible) by their Cherenkov radiation in liquid hydrogen (?-illegible) was measured by stopping (illegible) mesons in the hydrogen and detecting their decay electrons outside (?-illegible) of the flask (?-illegible) after a suitable time delay. An average detection (?-illegible) efficiency (?-illegible) of 75% (?-illegible) was (illegible) taken over the volume of the hydrogen (?-illegible).

Zipi, T.F.; Chamberlain, Owen; Kadyk, John A.; York, Carl M.

1963-05-09T23:59:59.000Z

36

Improvements to the on-line mass separator, RAMA, and the beta-delayed charged-particle emission of proton-rich sd shell nuclei  

SciTech Connect

To overcome the extreme difficulties encountered in the experimental decay studies of proton drip line nuclei, several techniques have been utilized, including a helium-jet transport system, particle identification detectors and mass separation. Improvements to the ion source/extraction region of the He-jet coupled on-line Recoil Atom Mass Analyzer (RAMA) and its target/ion source coupling resulted in significant increases in RAMA efficiencies and its mass resolution, as well as reductions in the overall transit time. At the 88-Inch Cyclotron at LBNL, the decays of {sup 31}Cl, {sup 27}P and {sup 28}P, with half-lives of 150 msec, 260 msec and 270.3 msec, respectively, were examined using a he-jet and low-energy gas {Delta}E-gas {Delta}E-silicon E detector telescopes. Total beta-delayed proton branches of 0.3% and 0.07% in {sup 31}Cl and {sub 27}P, respectively, were estimated. Several proton peaks that had been previously assigned to the decay of {sup 31}Cl were shown to be from the decay of {sup 25}Si. In {sup 27}P, two proton groups at 459 {+-} 14 keV and 610 {+-} 11 keV, with intensities of 7 {+-} 3% and 92 {+-} 4% relative to the main (100%) group were discovered. The Gamow-Teller component of the preceding beta-decay of each observed proton transition was compared to results from shell model calculations. Finally, a new proton transition was identified, following the {beta}-decay of {sup 28}P, at 1,444 {+-} 12 keV with a 1.7 {+-} 0.5% relative intensity to the 100% group. Using similar low-energy detector telescopes and the mass separator TISOL at TRIUMF, the 109 msec and 173 msec activities, {sup 17}Ne and {sup 33}Ar, were studied. A new proton group with energy 729 {+-} 15 keV was observed following the beta-decay of {sup 17}Ne. Several discrepancies between earlier works as to the energies, intensities and assignments of several proton transitions from {sup 17}Ne and {sup 33}Ar were resolved.

Ognibene, T.J. [Lawrence Berkeley National Lab., CA (United States). Nuclear Science Div.

1996-03-01T23:59:59.000Z

37

The Particle Adventure | Particle decays and annihiliations ...  

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

alphabet: (alpha), (beta), and (gamma). Alpha particles are helium nuclei (2 p, 2 n): Beta particles are speedy electrons: Gamma radiation is a high-energy photon: These three...

38

Understanding Nuclei in the upper sd - shell  

E-Print Network (OSTI)

Nuclei in the upper-$sd$ shell usually exhibit characteristics of spherical single particle excitations. In the recent years, employment of sophisticated techniques of gamma spectroscopy has led to observation of high spin states of several nuclei near A$\\simeq$ 40. In a few of them multiparticle, multihole rotational states coexist with states of single particle nature. We have studied a few nuclei in this mass region experimentally, using various campaigns of the Indian National Gamma Array setup. We have compared and combined our empirical observations with the large-scale shell model results to interpret the structure of these nuclei. Indication of population of states of large deformation has been found in our data. This gives us an opportunity to investigate the interplay of single particle and collective degrees of freedom in this mass region.

M. Saha Sarkar; Abhijit Bisoi; Sudatta Ray; Ritesh Kshetri; S. Sarkar

2013-08-01T23:59:59.000Z

39

Multiple channel programmable coincidence counter  

DOE Patents (OSTI)

A programmable digital coincidence counter having multiple channels and featuring minimal dead time. Neutron detectors supply electrical pulses to a synchronizing circuit which in turn inputs derandomized pulses to an adding circuit. A random access memory circuit connected as a programmable length shift register receives and shifts the sum of the pulses, and outputs to a serializer. A counter is input by the adding circuit and downcounted by the serializer, one pulse at a time. The decoded contents of the counter after each decrement is output to scalers.

Arnone, G.J.

1989-02-27T23:59:59.000Z

40

The Velocity-Selecting Cerenkov Counter  

E-Print Network (OSTI)

BAFFLE VELOCITY - SELECTING CERENKOV COUNTER (C 2) FiJI. 1velocity-selectinp: Cerenkov counter. ueaL-31;S CYLINDRICA~

Chamberlain, Owen; Weigand, Clyde

1956-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

A Liquid-Hydrogen Cerenkov Counter  

E-Print Network (OSTI)

^•BsêS A LIQUID-HYDROGEN CERENKOV COUNTER t • > f «lf ,«f X'i£ Si -tel A LIQUID-HYDROGEN CERENKOV COUNTER t V« Berkeley,

Zipi, T.F.; Chamberlain, Owen; Kadyk, John A.; York, Carl M.

1963-01-01T23:59:59.000Z

42

Countering Nuclear Terrorism | National Nuclear Security Administration  

National Nuclear Security Administration (NNSA)

Countering Nuclear Terrorism | National Nuclear Security Administration Countering Nuclear Terrorism | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog The National Nuclear Security Administration Countering Nuclear Terrorism Home > Our Mission > Countering Nuclear Terrorism Countering Nuclear Terrorism NNSA provides expertise, practical tools, and technically informed policy

43

Superheavy Nuclei: Relativistic Mean Field Outlook  

E-Print Network (OSTI)

The analysis of quasiparticle spectra in heaviest $A\\sim 250$ nuclei with spectroscopic data provides an additional constraint for the choice of effective interaction for the description of superheavy nuclei. It strongly suggest that only the parametrizations of the relativistic mean field Lagrangian which predict Z=120 and N=172 as shell closures are reliable for superheavy nuclei. The influence of the central depression in the density distribution of spherical superheavy nuclei on the shell structure is studied. Large central depression produces large shell gaps at Z=120 and N=172. The shell gaps at Z=126 and N=184 are favored by a flat density distribution in the central part of nucleus. It is shown that approximate particle number projection (PNP) by means of the Lipkin-Nogami method removes pairing collapse seen at these gaps in the calculations without PNP.

A. V. Afanasjev

2006-12-20T23:59:59.000Z

44

Basic Research Needs for Countering Terrorism  

SciTech Connect

To identify connections between technology needs for countering terrorism and underlying science issues and to recommend investment strategies to increase the impact of basic research on efforts to counter terrorism

Stevens, W.; Michalske, T.; Trewhella, J.; Makowski, L.; Swanson, B.; Colson, S.; Hazen, T.; Roberto, F.; David Franz, D.; Resnick, G.; Jacobson, S.; Valdez, J.; Gourley, P.; Tadros, M.; Sigman, M.; Sailor, M.; Ramsey, M.; Smith, B.; Shea, K.; Hrbek, J.; Rodacy, P.; Tevault, D.; Edelstein, N.; Beitz, J.; Burns, C.; Choppin, G.; Clark, S.; Dietz, M.; Rogers, R.; Traina, S.; Baldwin, D.; Thurnauer, M.; Hall, G.; Newman, L.; Miller, D.; Kung, H.; Parkin, D.; Shuh, D.; Shaw, H.; Terminello, L.; Meisel, D.; Blake, D.; Buchanan, M.; Roberto, J.; Colson, S.; Carling, R.; Samara, G.; Sasaki, D.; Pianetta, P.; Faison, B.; Thomassen, D.; Fryberger, T.; Kiernan, G.; Kreisler, M.; Morgan, L.; Hicks, J.; Dehmer, J.; Kerr, L.; Smith, B.; Mays, J.; Clark, S.

2002-03-01T23:59:59.000Z

45

Countering Nuclear Terrorism | National Nuclear Security Administratio...  

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

Countering Nuclear Terrorism | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response...

46

Single particle characterization, source apportionment, and aging effects of ambient aerosols in Southern California  

E-Print Network (OSTI)

detection efficiencies of aerosol time of flight masscomposition of ambient aerosol particles. Environmentalsize dependent response of aerosol counters, Atmospheric

Shields, Laura Grace

2008-01-01T23:59:59.000Z

47

Investigations of three-, four-, and five-particle decay channels of levels in light nuclei created using a {sup 9}C beam  

Science Conference Proceedings (OSTI)

The interactions of an E/A=70-MeV {sup 9}C beam with a Be target was used to populate levels in Be, B, and C isotopes, which undergo decay into many-particle exit channels. The decay products were detected in the HiRA array and the level energies were identified from their invariant mass. Correlations between the decay products were examined to deduce the nature of the decays, specifically to what extent all the fragments were created in one prompt step or whether the disintegration proceeded in a sequential fashion through long-lived intermediate states. In the latter case, information on the spin of the level was also obtained. Of particular interest is the five-body decay of the {sup 8}C ground state, which was found to disintegrate in two steps of two-proton decay passing through the {sup 6}Be{sub g.s.} intermediate state. The isobaric analog of {sup 8}C{sub g.s.} in {sup 8}B was also found to undergo two-proton decay to the isobaric analog of {sup 6}Be{sub g.s.} in {sup 6}Li. A 9.69-MeV state in {sup 10}C was found to undergo prompt four-body decay to the 2p + 2{alpha} exit channel. The two protons were found to have a strong enhancement in the diproton region and the relative energies of all four p-{alpha} pairs were consistent with the {sup 5}Li{sub g.s.} resonance.

Charity, R. J.; Elson, J. M.; Manfredi, J.; Shane, R.; Sobotka, L. G.; Brown, B. A.; Chajecki, Z.; Coupland, D.; Iwasaki, H.; Kilburn, M.; Lee, Jenny; Lynch, W. G.; Sanetullaev, A.; Tsang, M. B.; Winkelbauer, J.; Youngs, M.; Marley, S. T.; Shetty, D. V.; Wuosmaa, A. H.; Ghosh, T. K. [Departments of Chemistry and Physics, Washington University, St. Louis, Missouri 63130 (United States); National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008 (United States); Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064 (India); Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903 (United States)

2011-07-15T23:59:59.000Z

48

Boron-10 Lined Proportional Counter Wall Effects  

SciTech Connect

The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube based system in the configuration of a coincidence counter. This report provides information about how variations in proportional counter radius and gas pressure in a typical coincident counter design might affect the observed signal from boron-lined tubes. A discussion comparing tubes to parallel plate counters is also included.

Siciliano, Edward R.; Kouzes, Richard T.

2012-05-01T23:59:59.000Z

49

Nuclear Shell Structure and Beta Decay I. Odd A Nuclei II. Even A Nuclei  

DOE R&D Accomplishments (OSTI)

In Part I a systematics is given of all transitions for odd A nuclei for which sufficiently reliable data are available. The allowed or forbidden characters of the transitions are correlated with the positions of the initial and final odd nucleon groups in the nuclear shell scheme. The nuclear shells show definite characteristics with respect to parity of the ground states. The latter is the same as the one obtained from known spins and magnetic moments in a one-particle interpretation. In Part II a systematics of the beta transitions of even-A nuclei is given. An interpretation of the character of the transitions in terms of nuclear shell structure is achieved on the hypothesis that the odd nucleon groups have the same structure as in odd-A nuclei, together with a simple coupling rule between the neutron and proton groups in odd-odd nuclei.

Mayer, M.G.; Moszkowski, S.A.; Nordheim, L.W.

1951-05-00T23:59:59.000Z

50

Fission Barriers of Compound Superheavy Nuclei  

E-Print Network (OSTI)

The dependence of fission barriers on the excitation energy of the compound nucleus impacts the survival probability of superheavy nuclei synthesized in heavy-ion fusion reactions. In this work, we investigate the isentropic fission barriers by means of the self-consistent nuclear density functional theory. The relationship between isothermal and isentropic descriptions is demonstrated. Calculations have been carried out for $^{264}$Fm, $^{272}$Ds, $^{278}$112, $^{292}$114, and $^{312}$124. For nuclei around $^{278}$112 produced in "cold fusion" reactions, we predict a more rapid decrease of fission barriers with excitation energy as compared to the nuclei around $^{292}$114 synthesized in "hot fusion" experiments. This is explained in terms of the difference between the ground-state and saddle-point temperatures. The effect of the particle gas is found to be negligible in the range of temperatures studied.

J. C. Pei; W. Nazarewicz; J. A. Sheikh; A. K. Kerman

2009-01-07T23:59:59.000Z

51

Evaluation of waste crate counter  

Science Conference Proceedings (OSTI)

A novel nondestructive measurement system has been developed to perform combined gamma-ray, passive neutron, and active neutron analyses of radioactive waste packaged in large crates. The system will be used to examine low level and transuranic waste at the Waste Receiving and Processing facility at Westinghouse-Hanford Corp. Prior to delivery of the system, an extensive evaluation of its performance characteristics will be conducted. The evaluation is to include an assessment of the mechanical properties of the system, gamma-ray attenuation correction algorithms, instrument response as a function of source positions, performance of the high resolution gamma-ray detector for ``hot spot`` and isotopic analyses, active and passive neutron counter response, instrument sensitivity, matrix effects, and packaging effects. This report will discuss the findings of the evaluation program, to date, and indicate future directions for the program.

Wachter, J.R. [Los Alamos National Lab., NM (United States). Nuclear Materials Measurement and Accountability; Bieri, J.M. [Pajarito Scientific Corp., Los Alamos, NM (United States); Shaw, S.W. [Westinghouse Hanford Co., Richland, WA (United States)

1994-08-01T23:59:59.000Z

52

Counter-ions at single charged wall: Sum rules  

E-Print Network (OSTI)

For inhomogeneous classical Coulomb fluids in thermal equilibrium, like the jellium or the two-component Coulomb gas, there exists a variety of exact sum rules which relate the particle one-body and two-body densities. The necessary condition for these sum rules is that the Coulomb fluid possesses good screening properties, i.e. the particle correlation functions or the averaged charge inhomogeneity, say close to a wall, exhibit a short-range (usually exponential) decay. In this work, we study equilibrium statistical mechanics of an electric double layer with counter-ions only, i.e. a globally neutral system of equally charged point-like particles in the vicinity of a plain hard wall carrying a fixed uniform surface charge density of opposite sign. At large distances from the wall, the one-body and two-body counter-ion densities go to zero slowly according to the inverse-power law. In spite of the absence of screening, all known sum rules are shown to hold for two exactly solvable cases of the present system: in the weak-coupling Poisson-Boltzmann limit (in any spatial dimension larger than one) and at a special free-fermion coupling constant in two dimensions. This fact indicates an extended validity of the sum rules and provides a consistency check for reasonable theoretical approaches.

Ladislav Samaj

2013-04-15T23:59:59.000Z

53

Present Status of the Theory of Fission of hot Nuclei  

E-Print Network (OSTI)

Recent progress in the theory of fission of hot nuclei is reported. We discuss in particular the properties of the friction formfactor as function of the deformation (and possibly of the temperature) which are necessary to reproduce data concerning fission of hot nuclei and its accompanying light particle and $\\gamma$-ray emission. Recent theoretical work gives support to a phenomenological friction form factor (proposed some time ago), which is weak for compact shapes and increases on the way to scission.

P. Fröbrich

2004-01-21T23:59:59.000Z

54

Introduction to the study of collisions between heavy nuclei  

SciTech Connect

Current investigations concerning the collisions of nuclei governed by small de Broglie wavelengths are reviewed. The wave packets localize nuclei in regions small compared to their diameters. Cross sections are examined for potential scattering, elastic scattering, quasi-molecular states, peripheral particle-transfer reactions, fusion, and deep inelastic collisions. Theories of fusion and deep inelastic collisions are summarized. This paper is in the nature of a review-tutorial. 45 references, 51 figures, 2 tables. (RWR)

Bayman, B.F.

1980-01-01T23:59:59.000Z

55

Search for ?-Mesic Nuclei at J-PARC  

E-Print Network (OSTI)

The merits of searching for \\eta -mesic nuclei by use of the (\\pi, N) reaction at J-PARC is discussed, by comparison with an old experiment with the same reaction at BNL in 1980's. The importance of a pilot experiment using deuterium target is also stressed for a better understanding of the background which should exist even after the coincidence of the decay particles of \\eta -mesic nuclei.

H. Fujioka

2010-11-03T23:59:59.000Z

56

Decay modes of $^{10}$C nuclei unbound state  

E-Print Network (OSTI)

Unbound states of $^{10}$C nuclei produced as quasi-projectiles in $^{12}$C+$^{24}$Mg collisions at E/A = 53 and 95 MeV are studied with the Indra detector array. Multi-particle correlation function analyses provide experimental evidence of sequential de-excitation mechanisms through the production of intermediate $^{9}$B, $^{6}$Be and $^{8}$Be unbound nuclei. The relative contributions of different decay sequences to the total decay width of the explored states is estimated semi-quantitatively. The obtained results show that heavy-ion collisions can be used as a tool to access spectroscopic information about exotic nuclei.

F. Grenier; A. Chbihi; R. Roy; G. Verde; D. Thériault; J. D. Frankland; J. P. Wieleczko; B. Borderie; R. Bougault; R. Dayras; E. Galichet; D. Guinet; P. Lautesse; N. Le Neindre; O. Lopez; J. Moisan; L. Nalpas; M. Pârlog; M. F. Rivet; E. Rosato; B. Tamain; E. Vient; M. Vigilante

2007-06-29T23:59:59.000Z

57

GEIGER-MULLER TYPE COUNTER TUBE  

DOE Patents (OSTI)

A single counter tube capable of responding to a wide range of intensities is described. The counter tube comprises a tubular cathode and an anode extending centrally of the cathode. The spacing between the outer surface of the anode and the inner surface of the cathode is varied along the length of the tube to provide different counting volumes in adjacent portions of the tube. A large counting volume in one portion adjacent to a low-energy absorption window gives adequate sensitivity for measuring lowintensity radiation, while a smaller volume with close electrode spacing is provided in the counter to make possible measurement of intense garnma radiation fields.

Fowler, I.L.; Watt, L.A.K.

1959-12-15T23:59:59.000Z

58

Mechanical Properties of Counter-gravity Cast IN718  

Science Conference Proceedings (OSTI)

Key Words: Counter-gravity, investment casting, superalloys, IN718, inert ... using the Counter-gravity Low-pressure Inert-atmosphere (CLI) investment casting ...

59

The decay of hot nuclei  

Science Conference Proceedings (OSTI)

The formation of hot compound nuclei in intermediate-energy heavy ion reactions is discussed. The statistical decay of such compound nuclei is responsible for the abundant emission of complex fragments and high energy gamma rays. 43 refs., 23 figs.

Moretto, L.G.; Wozniak, G.J.

1988-11-01T23:59:59.000Z

60

The neutron long counter NERO for studies of beta-delayed neutron emission in the r-process  

E-Print Network (OSTI)

The neutron long counter NERO was built at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, for measuring beta-delayed neutron-emission probabilities. The detector was designed to work in conjunction with a beta-decay implantation station, so that beta decays and beta-delayed neutrons emitted from implanted nuclei can be measured simultaneously. The high efficiency of about 40%, for the range of energies of interest, along with the small background, are crucial for measuring beta-delayed neutron emission branchings for neutron-rich r-process nuclei produced as low intensity fragmentation beams in in-flight separator facilities.

J. Pereira; P. Hosmer; G. Lorusso; P. Santi; A. Couture; J. Daly; M. Del Santo; T. Elliot; J. Goerres; C. Herlitzius; K. -L. Kratz; L. O. Lamm; H. Y. Lee; F. Montes; M. Ouellette; E. Pellegrini; P. Reeder; H. Schatz; F. Schertz; L. Schnorrenberger; K. Smith; E. Stech; E. Strandberg; C. Ugalde; M. Wiescher; A. Woehr

2010-07-28T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

COUNTER DISASTER AND RECOVERY PLAN -UNIVERSITY RECORDS  

E-Print Network (OSTI)

...................................................................................10 3.1 Disaster Response and Recovery Team...........................................10 3.2 Emergency Disaster Response.......................................................................23 6.1 AssessingCOUNTER DISASTER AND RECOVERY PLAN - UNIVERSITY RECORDS Records Management & Archives Murdoch

62

Calibration of a long counter for fast neutrons with energies from 2 to 14 MeV  

E-Print Network (OSTI)

To determine if a Hansen and McKibben type shielded long counter has a flat response from 2 MeV to 14 Mev detector efficiency was experimentally measured using a PuBe source. Calculations using the Monte Carlo program, MCNP, were performed to determine the efficiency of the detector for both PuBe and 14 MeV neutrons. The detector used a boron triflouride proportional counter as its counting device. Measurements were made using two 1 0 curie PuBe neutron sources (combined source strength of 4.02E+07 neutrons/second) to determine the detectors efficiency at the mean energy of the source, 4.3 MeV. The detector was found to have an efficiency of 0.85 counts-centimeter2/neutron at a source to detector distance of 1 meter. This compares favorably with previous measurements with long counters of similar configuration. The determination of the counter's effective center indicated that the effective center for the counter is 8.7 + 0.1 centimeters behind the front face of the detector. Attempts to use foil activation to determine the flux at the counter proved unsuccessful as the source strength was insufficient to activate the foils sufficiently. The Monte Carlo code, MCNP, was used to model a 150 KeV neutron generator source for 14 MeV neutrons, and the combined 1 0 Ci PuBe source experiment in order to determine the (n, a) reaction rate in the BF3 detector of the long counter, thereby simulating the long counter's response. For the PuBe source the efficiency of the long counter was computed to be 0.54 counts-centimeter2/particle at a source to detector distance of 60 centimeters. This is slightly less than the 0.6 counts-centimeter2/neutron achieved experimentally with the actual long counter, for a 20 Ci PuBe source prior to applying the correction for the detector's effective center, at the same distance. The MCNP model also was used to determined a long counter efficiency of 0.39 counts-centimeter2/particle for 14.74 MeV neutrons at a source to detector distance of 60 centimeters. This suggests that the long counter response is not flat over the 2 to 14 MeV energy range; however, tests indicated that the long counters efficiency on depends on the BF3 tube position in the long counter and that a flatter response over the energy range of interest may be obtained by adjusting the position of the BF3 tube.

Orr, Michael Lee

1993-01-01T23:59:59.000Z

63

From Hydrogen Fuel Stations to Bean Counters, NIST Weights ...  

Science Conference Proceedings (OSTI)

From Hydrogen Fuel Stations to Bean Counters, NIST Weights and Measures Works to Meet Market Needs. ...

2010-08-23T23:59:59.000Z

64

Dynamic Chirality in Nuclei  

SciTech Connect

The possible chiral interpretation of twin bands in odd-odd nuclei was investigated in the Interacting Boson Fermion-Fermion Model. The analysis of the wave functions has shown that the possibility for angular momenta of the valence proton, neutron and core to find themselves in the favorable, almost orthogonal geometry is present, but not dominant. Such behaviour is found to be similar in nuclei where both the level energies and the electromagnetic decay properties display the chiral pattern, as well as in those where only the energies of the corresponding levels in the twin bands are close together. The difference in the structure of the two types of chiral candidates nuclei can be attributed to different beta and gamma fluctuations, induced by the exchange boson-fermion interaction of the Interacting Boson Fermion-Fermion Model. In both cases the chirality is weak and dynamic. The existence of doublets of bands in {sup 134}Pr can be attributed to dynamic chirality dominated by shape fluctuations.

Tonev, D. [Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Angelis, G. de [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Brant, S. [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Petkov, P. [Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); Ventura, A. [ENEA, 40129 Bologna and INFN, Sezione di Bologna (Italy)

2009-08-26T23:59:59.000Z

65

The AMS-01 Aerogel Threshold ?Cerenkov counter.  

E-Print Network (OSTI)

The Alpha Magnetic Spectrometer in a precursor version (AMS-01), was flown in June 1998 on a 51.6 ? orbit and at altitudes ranging between 320 and 390 km, on board of the space shuttle Discovery (flight STS-91). AMS-01 included an Aerogel Threshold ? Cerenkov counter (ATC) to separate ¯p from e ? and e + from p, for momenta below 3.5 GeV/c. This paper presents a description of the ATC counter and reports on its performances during the flight STS-91.

D. Barancourt A; F. Barao B; G. Barbier A; G. Barreira C; M. Buénerd A; G. Castellini D; E. Choumilov E; J. Favier B; N. Fouque B; A. Gougas F; V. Hermel B; R. Kossakowski B; G. Laborie A; G. Laurenti G; S. -c. Lee F; F. Mayet A; B. Meillon A; Y. -t. Oyang F; V. Plyaskin E; V. Pojidaev E; C. Rossin A; D. Santos A; F. Vezzu A; J. P. Vialle B

2000-01-01T23:59:59.000Z

66

Ice Nuclei, Rainwater Chemical Composition, and Static Cloud Seeding Effects in Israel  

Science Conference Proceedings (OSTI)

This study analyzed the temporal and spatial variation of natural ice nuclei (IN), total suspended particles (TSP), and rainwater chemical composition (RCC) in Israel. This research is complementary to the statistical analyses of cloud seeding, ...

Yoav Levi; Daniel Rosenfeld

1996-09-01T23:59:59.000Z

67

A Four Channel 250 MHz Visual Counter  

Science Conference Proceedings (OSTI)

A visual counter rated at 250 mhz. with a pulse-pair resolution of 2.6 nanoseconds for nuclear instrument module (NIM) signals has been designed. Pulse widths for NIM signals must be equal to or greater than 2 ns. The counter has a separate input for transistor-transistor logic (TTL) signals and for this logic level it operates at rates equal to or less than 190 mhz. TTL pulses must be greater than 4 ns. The design was implemented on a printed circuit card. Four of these cards were packaged into a single unit resulting in a four channel device that can be mounted into a 19 inch rack. Seven units were built; they are presently used in the experimental area and in the Main Control Room of the Bevalac. The counter accepts well defined NIM or TTL signals internally terminated with 50 ohms. All the controls and the signal input connectors are located on the front panel. An Overflow output, Gate, and Reset inputs are located on the back panel. The counters have 8 Light Emitting Diode digit displays which are 20.3 mm high with a viewing distance rating of 10 meters. Light filters are used for the LED displays greatly enhancing their visibility.

Flores, I.; Blando, P.; Crawford, H.; Engelage, J.; Greiner, L.; Ko, S.; Krebs, G.; Visser, G.

1992-04-01T23:59:59.000Z

68

Clusters in Light Nuclei  

E-Print Network (OSTI)

A great deal of research work has been undertaken in the alpha-clustering study since the pioneering discovery, half a century ago, of 12C+12C molecular resonances. Our knowledge of the field of the physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. In this work, the occurence of "exotic" shapes in light N=Z alpha-like nuclei is investigated. Various approaches of superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Results on clustering aspects are also discussed for light neutron-rich Oxygen isotopes.

C. Beck; P. Papka; A. Sanchez i Zafra; S. Thummerer; F. Azaiez; P. Bednarczyk; S. Courtin; D. Curien; O. Dorvaux; A. Goasduff; D. Lebhertz; A. Nourreddine; M. Rousseau; M. -D. Salsac; W. von Oertzen; B. Gebauer; C. Wheldon; Tz. Kokalova; G. Efimov; V. Zherebchevsky; Ch. Schulz; H. G. Bohlen; D. Kamanin; G. de Angelis; A. Gadea; S. Lenzi; D. R. Napoli; S. Szilner; M. Milin; W. N. Catford; D. G. Jenkins; G. Royer

2010-11-15T23:59:59.000Z

69

///COUNTER : an artistic system for the transmission of cultural energy  

E-Print Network (OSTI)

My thesis introduces ///COUNTER as an artistic system for the transmission of cultural energy. The underlying concepts of ///COUNTER are derived directly from my work on energy access as developed through the eWheel and ...

Vincent de Paul, Jegan Joyston

2009-01-01T23:59:59.000Z

70

Why are the interband transitions among triaxially strongly deformed bands suppressed in even nuclei?  

Science Conference Proceedings (OSTI)

As top-on-top model has made a great success in explaining triaxially strongly deformed (TSD) bands in odd-A nuclei, we extend this model to even-A nuclei, i.e. two particles in different single-particle orbitals outside the triaxial rotor. In the lowest order approximation, the electromagnetic transitions between TSD bands in even-A case are reduced by a factor of 0.04 compared with odd-A case. It is one of the reasons why TSD bands are not yet explicitly observed in even-A nuclei.

Sugawara-Tanabe, Kazuko [Otsuma Women's University, Tama, Tokyo 206-8540 (Japan); Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Tanabe, Kosai [Department of Physics, Saitama University, Sakura-ku, Saitama 338-8570 (Japan); Theoretical Nuclear Physics Laboratory, RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)

2011-05-06T23:59:59.000Z

71

Real-Counter automata and their decision problems  

Science Conference Proceedings (OSTI)

We introduce real-counter automata, which are two-way finite automata augmented with counters that take real values. In contrast to traditional word automata that accept sequences of symbols, real-counter automata accept real words that are bounded and ...

Zhe Dang; Oscar H. Ibarra; Pierluigi San Pietro; Gaoyan Xie

2004-12-01T23:59:59.000Z

72

Shape coexistence in atomic nuclei  

Science Conference Proceedings (OSTI)

Shape coexistence in nuclei appears to be unique in the realm of finite many-body quantum systems. It differs from the various geometrical arrangements that sometimes occur in a molecule in that in a molecule the various arrangements are of the widely separated atomic nuclei. In nuclei the various ''arrangements'' of nucleons involve (sets of) energy eigenstates with different electric quadrupole properties such as moments and transition rates, and different distributions of proton pairs and neutron pairs with respect to their Fermi energies. Sometimes two such structures will ''invert'' as a function of the nucleon number, resulting in a sudden and dramatic change in ground-state properties in neighboring isotopes and isotones. In the first part of this review the theoretical status of coexistence in nuclei is summarized. Two approaches, namely, microscopic shell-model descriptions and mean-field descriptions, are emphasized. The second part of this review presents systematic data, for both even- and odd-mass nuclei, selected to illustrate the various ways in which coexistence is observed in nuclei. The last part of this review looks to future developments and the issue of the universality of coexistence in nuclei. Surprises continue to be discovered. With the major advances in reaching to extremes of proton-neutron number, and the anticipated new ''rare isotope beam'' facilities, guidelines for search and discovery are discussed.

Heyde, Kris; Wood, John L. [Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium); School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States)

2011-10-01T23:59:59.000Z

73

Reaction theories for exotic nuclei  

Science Conference Proceedings (OSTI)

This contribution discusses two important dynamical effects in the scattering of exotic beams. The first part deals proton breakup. The Coulomb interactions between the core and the target and the proton and the target are treated to all orders, including also the full multipole expansion of the Coulomb potential. The dynamics of proton Coulomb breakup is compared to that of an equivalent neutron of larger binding energy in order to elucidate the differences with the well understood neutron breakup mechanism. With respect to nuclear breakup it is found that a proton behaves exactly as a neutron of larger binding energy. The extra 'effective energy' is due to the combined core-target Coulomb barrier. In Coulomb breakup we distinguish the effect of the core-target Coulomb potential (called recoil effect), with respect to which the proton behaves again as a more bound neutron, from the direct proton-target Coulomb potential. The latter gives cross sections about an order of magnitude larger than the recoil term. The two effects give rise to complicated interferences in the parallel momentum distributions. They are instead easily separable in the proton angular distributions which are therefore suggested as a very useful observable for future experimental studies. The second part has to do with the dynamics of one-neutron and one-proton removal from unstable nuclei with large asymmetry {Delta}S S{sub n}-S{sub p} in the separation energies and incident energies below 80 MeV/nucleon. Strong non-sudden effects are observed in the case of deeply-bound-nucleon removal. The corresponding parallel momentum distributions exhibit an abrupt cutoff at high momentum that corresponds to an energy threshold occurring when the incident energy per particle is of comparable magnitude as the nucleon separation energy.

Bonaccorso, Angela [INFN, Sez. di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy)

2012-11-20T23:59:59.000Z

74

P-odd, P-even, and T-odd asymmetries in true quaternary fission of nuclei  

Science Conference Proceedings (OSTI)

The coefficients of P-odd, P-even, and T -odd asymmetries for a third and a fourth prescission particle emitted in the true quaternary fission of nuclei that was induced by polarized cold neutrons were studied on the basis of quantum-mechanical fission theory. By using non-evaporation (nonadiabatic) mechanisms of light-particle emission, these coefficients were compared with the analogous coefficients for prescission third particles emitted in the ternary fission of nuclei.

Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Titova, L. V. [Voronezh State University (Russian Federation)] [Voronezh State University (Russian Federation)

2013-04-15T23:59:59.000Z

75

Boron-10 Lined Proportional Counter Model Validation  

SciTech Connect

The Department of Energy Office of Nuclear Safeguards (NA-241) is supporting the project “Coincidence Counting With Boron-Based Alternative Neutron Detection Technology” at Pacific Northwest National Laboratory (PNNL) for the development of an alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a boron-lined proportional tube-based alternative system in the configuration of a coincidence counter. This report discusses the validation studies performed to establish the degree of accuracy of the computer modeling methods current used to simulate the response of boron-lined tubes. This is the precursor to developing models for the uranium neutron coincidence collar under Task 2 of this project.

Lintereur, Azaree T.; Siciliano, Edward R.; Kouzes, Richard T.

2012-06-30T23:59:59.000Z

76

ARM - Field Campaign - MASRAD: Cloud Condensate Nuclei Chemistry  

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

govCampaignsMASRAD: Cloud Condensate Nuclei Chemistry Measurements govCampaignsMASRAD: Cloud Condensate Nuclei Chemistry Measurements Campaign Links AMF Point Reyes Website Related Campaigns MArine Stratus Radiation Aerosol and Drizzle (MASRAD) IOP 2005.03.14, Miller, AMF Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : MASRAD: Cloud Condensate Nuclei Chemistry Measurements 2005.07.01 - 2005.07.30 Lead Scientist : Carl Berkowitz For data sets, see below. Description Principal Investigators: J. Ogren, C. Berkowitz, R. Halthore, A. Laskin, A. Strawa, J. Wang, A. Wexler As part of the ARM Mobile Facility (AMF) deployment to Point Reyes, CA in the spring and summer of 2005, a suite of instrumentation was installed to measure the chemical, physical and optical properties of aerosol particles

77

Hardware support for software controlled fast multiplexing of performance counters  

DOE Patents (OSTI)

Performance counters may be operable to collect one or more counts of one or more selected activities, and registers may be operable to store a set of performance counter configurations. A state machine may be operable to automatically select a register from the registers for reconfiguring the one or more performance counters in response to receiving a first signal. The state machine may be further operable to reconfigure the one or more performance counters based on a configuration specified in the selected register. The state machine yet further may be operable to copy data in selected one or more of the performance counters to a memory location, or to copy data from the memory location to the counters, in response to receiving a second signal. The state machine may be operable to store or restore the counter values and state machine configuration in response to a context switch event.

Salapura, Valentina; Wisniewski, Robert W.

2013-01-01T23:59:59.000Z

78

Deactivation of ice nuclei due to atmospherically relevant surface coatings  

SciTech Connect

The ice nucleation characteristics of Arizona Test Dust (ATD) and illite clay, surrogates for atmospheric ice nuclei, have been determined at the Aerosol Interactions and Dynamics in the Atmosphere (AIDA) chamber located at the Research Center Karlsruhe in Germany. The objective of this research was to determine the effect of sulphuric acid and ammonium sulphate coatings on the ability of these mineral dust surrogates to nucleate ice in an environment where particles realistically compete for water vapor. Coated ATD particles required higher saturations at all investigated temperatures, from -20 to -45º C, than did identical uncoated particles. Freezing of coated particles often required saturations approaching those for the homogeneous freezing of aqueous solutions of the coating material alone. Less pronounced effects were found for illite although the presence of a coating consistently increased the saturation or decreased the temperature required for ice formation. Analysis of ice residue at the single particle level suggests that the first coated particles to freeze had thinner or incomplete coatings when compared to particles that froze later in the expansion. This observation highlights a need to verify coating properties since an assumption of homogeneity of a group of coated aerosol may be incorrect. The increase in saturation ratio for freezing suggests that gas-phase uptake of sulphates, a large fraction of which are due to anthropogenic emissions, will reduce the ice and mixed-phase cloud formation potential of atmospheric ice nuclei.

Cziczo, Daniel J.; Froyd, Karl D.; Gallavardin, S. J.; Moehler, Ottmar; Benz, Stefan; Saathoff, Harald; Murphy, Daniel M.

2009-11-23T23:59:59.000Z

79

Systematic Study of Fission Barriers of Excited Superheavy Nuclei  

E-Print Network (OSTI)

A systematic study of fission-barrier dependence on excitation energy has been performed using the self-consistent finite-temperature Hartree-Fock+BCS (FT-HF+BCS) formalism with the SkM* Skyrme energy density functional. The calculations have been carried out for even-even superheavy nuclei with Z ranging between 110 and 124. For an accurate description of fission pathways, the effects of triaxial and reflection-asymmetric degrees of freedom have been fully incorporated. Our survey demonstrates that the dependence of isentropic fission barriers on excitation energy changes rapidly with particle number, pointing to the importance of shell effects even at large excitation energies characteristic of compound nuclei. The fastest decrease of fission barriers with excitation energy is predicted for deformed nuclei around N=164 and spherical nuclei around N=184 that are strongly stabilized by ground-state shell effects. For nuclei 240Pu and 256Fm, which exhibit asymmetric spontaneous fission, our calculations predict a transition to symmetric fission at high excitation energies due to the thermal quenching of static reflection asymmetric deformations.

J. A. Sheikh; W. Nazarewicz; J. C. Pei

2009-04-24T23:59:59.000Z

80

Self-regulating neutron coincidence counter  

DOE Patents (OSTI)

A device for accurately measuring the mass of /sup 240/Pu and /sup 239/Pu in a sample having arbitrary moderation and mixed with various contaminants. The device utilizes a thermal neutron well counter which has two concentric rings of neutron detectors separated by a moderating material surrounding the well. Neutron spectroscopic information derived by the two rings of detectors is used to measure the quantity of /sup 239/Pu and /sup 240/Pu in device which corrects for background radiation, deadtime losses of the detector and electronics and various other constants of the system.

Baron, N.

1980-06-16T23:59:59.000Z

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


81

Spontaneous fission half-lives of nuclei in a phenomenological model  

E-Print Network (OSTI)

A simple phenomenological model, based on the \\'Swi{\\c a}tecki idea for evaluation of the spontaneous fission half-lives is proposed. The model contains only one adjustable parameter fixed to the data for even-even nuclei and two additional hindrance factors to the life-times, which give the effect of odd particles. A good agreement with the experimental data for all fissioning nuclei is achieved.

A. Zdeb; M. Warda; K. Pomorski

2013-11-08T23:59:59.000Z

82

Proton Distribution in Heavy Nuclei  

DOE R&D Accomplishments (OSTI)

It is reasoned that, from considerations connected with beta-decay stability and Coulomb repulsion forces, a neutron excess is developed on the surface of heavy nuclei. Several consequences of this qualitative analysis in nucleon interactions are briefly noted. (K.S.)

Johnson, M. H; Teller, E.

1953-11-13T23:59:59.000Z

83

Urban Cloud Condensation Nuclei Spectral Flux  

Science Conference Proceedings (OSTI)

The cloud condensation nuclei (CCN) spectral flux and the condensation nuclei (CN) flux from an urban area are determined from in situ aircraft measurements at Denver, Colorado. The concentration differences between upwind and downwind cross ...

Paul R. Frisbie; James G. Hudson

1993-04-01T23:59:59.000Z

84

Some Basic Characteristics of Bacterial Freezing Nuclei  

Science Conference Proceedings (OSTI)

Freezing spectra of INA bacteria from different parts of the world were compared. A slight increase in efficiency of freezing nuclei produced by strains from warmer climates was observed. Whole cells of the most efficient strain produced nuclei ...

S. A. Yankofsky; Z. Levin; T. Bertold; N. Sandlerman

1981-09-01T23:59:59.000Z

85

Boundary geometric control of a counter-current heat exchanger  

E-Print Network (OSTI)

Boundary geometric control of a counter-current heat exchanger Ahmed MAIDIa , Moussa DIAFb , Jean control of a counter-current heat exchanger whose control is designed considering a model based on two. The objective consists in controlling the internal fluid temperature, at the heat exchanger outlet

86

AIR ALPHA PROPORTIONAL COUNTER INSENSITIVE TO ATMOSPHERIC HUMIDITY  

SciTech Connect

A conventional alpha proportional counter which uses air as the counter gas is sensitive to high relative humidity and generates spurious pulses that cannot be distinguished from actual alpha pulses. It was found possible to operate such a counter satisfactorily at high relative humidity by passing a small current ( approximates 15 ma) through the center wire. In this manner the center wire is heated and the relative humidity of the surrounding sheath of air is reduced sufficiently so that operation of the counter at high relative humidity is comparable to operation with dry air, Two different mechanisms are proposed for the formation of spurious pulses in such a counter at high relative humidity. (auth)

Ferrari, A.M.R.; Borkowski, C.J.

1962-10-01T23:59:59.000Z

87

An Improved Airborne Aitken Nucleus Counter  

Science Conference Proceedings (OSTI)

An instrument has been designed for measuring with high accuracy and resolution the size and concentration of atmospheric particles ?0.005 ?m. It is pressure compensated for aircraft use and can take five readings per second with a system ...

C. G. Michael

1986-06-01T23:59:59.000Z

88

Counter-Rotating Tandem Motor Drilling System  

SciTech Connect

Gas Technology Institute (GTI), in partnership with Dennis Tool Company (DTC), has worked to develop an advanced drill bit system to be used with microhole drilling assemblies. One of the main objectives of this project was to utilize new and existing coiled tubing and slimhole drilling technologies to develop Microhole Technology (MHT) so as to make significant reductions in the cost of E&P down to 5000 feet in wellbores as small as 3.5 inches in diameter. This new technology was developed to work toward the DOE's goal of enabling domestic shallow oil and gas wells to be drilled inexpensively compared to wells drilled utilizing conventional drilling practices. Overall drilling costs can be lowered by drilling a well as quickly as possible. For this reason, a high drilling rate of penetration is always desired. In general, high drilling rates of penetration (ROP) can be achieved by increasing the weight on bit and increasing the rotary speed of the bit. As the weight on bit is increased, the cutting inserts penetrate deeper into the rock, resulting in a deeper depth of cut. As the depth of cut increases, the amount of torque required to turn the bit also increases. The Counter-Rotating Tandem Motor Drilling System (CRTMDS) was planned to achieve high rate of penetration (ROP) resulting in the reduction of the drilling cost. The system includes two counter-rotating cutter systems to reduce or eliminate the reactive torque the drillpipe or coiled tubing must resist. This would allow the application of maximum weight-on-bit and rotational velocities that a coiled tubing drilling unit is capable of delivering. Several variations of the CRTDMS were designed, manufactured and tested. The original tests failed leading to design modifications. Two versions of the modified system were tested and showed that the concept is both positive and practical; however, the tests showed that for the system to be robust and durable, borehole diameter should be substantially larger than that of slim holes. As a result, the research team decided to complete the project, document the tested designs and seek further support for the concept outside of the DOE.

Kent Perry

2009-04-30T23:59:59.000Z

89

Present Status of the Theory of Fission of hot Nuclei  

E-Print Network (OSTI)

Recent progress in the theory of fission of hot nuclei is reported. We discuss in particular the properties of the friction form factor as function of the deformation (and possibly of the temperature) which are necessary to reproduce data concerning fission of hot nuclei and its accompanying light particle and ?-ray emission. Recent theoretical work gives support to a phenomenological friction form factor (proposed some time ago 1)), which is weak for compact shapes and increases on the way to scission. Fission is one of the main decay channels after fusion of two heavy ions. The following discussion is restricted mainly to systems for which Bohr’s hypothesis is valid, which states that the formation and decay of the compound nucleus are independent processes, i. e. fission starts only after a completely equilibrated compound

Peter Fröbrich

2004-01-01T23:59:59.000Z

90

Single-particle structure of neutron-rich nuclei  

Science Conference Proceedings (OSTI)

Neutron transfer (d,p) reactions have been measured with rare isotope beams of {sup 132}Sn, {sup 130}Sn and {sup 134}Te accelerated to {approx}4.5 MeV/u interacting with CD{sub 2} targets. Reaction protons were detected in an early implementation of the ORRUBA array of position-sensitive silicon strip detectors. Neutron excitations in the 2f{sub 7/2}, 3p{sub 3/2}, 3p{sub 1/2} and 2f{sub 5/2} orbitals were populated.

Cizewski, J. A. [Rutgers University; Jones, K. L. [University of Tennessee, Knoxville (UTK); Kozub, R. L. [Tennessee Technological University; Pain, S. D. [Rutgers University; Bardayan, Daniel W [ORNL; ORRUBA_Collaboration, The [ORRUBA

2010-01-01T23:59:59.000Z

91

Effects of Aerosol Particles on the Microphysics of Coastal Stratiform Clouds  

Science Conference Proceedings (OSTI)

Aerosol particles can act as cloud condensation nuclei and thereby influence the number and size of droplets in clouds. Consequently, anthropogenic particles have the potential to influence global climate by increasing cloud albedo and decreasing ...

Cynthia H. Twohy; Philip A. Durkee; Barry J. Huebert; Robert J. Charlson

1995-04-01T23:59:59.000Z

92

Aerodynamic performance measurements in a counter-rotating aspirated compressor.  

E-Print Network (OSTI)

??This thesis is an experimental investigation of the aerodynamic performances of a counter-rotating aspirated compressor. This compressor is implemented in a blow-down facility, which gives… (more)

Onnée, Jean-François

2005-01-01T23:59:59.000Z

93

Aerodynamic performance measurements in a counter-rotating aspirated compressor  

E-Print Network (OSTI)

This thesis is an experimental investigation of the aerodynamic performances of a counter-rotating aspirated compressor. This compressor is implemented in a blow-down facility, which gives rigorous simulation of the ...

Onnée, Jean-François

2005-01-01T23:59:59.000Z

94

Surface Mounted Under Counter Dimmable LED Strip-STR8  

Science Conference Proceedings (OSTI)

The product under assessment is an advanced lighting technologya controllable, surface mounted under-counter light emitting diode (LED) strip lighting system that is designed to provide various levels of direct and indirect white light.

2008-06-12T23:59:59.000Z

95

On fitting planetary systems in counter-revolving configurations  

E-Print Network (OSTI)

In Gayon & Bois (2008) and Gayon etal (2009), (i) we studied the theoretical feasibility and efficiency of retrograde mean motion resonances (i.e. two planets are both in orbital resonance and in counter-revolving configuration), (ii) we showed that retrograde resonances can generate interesting mechanisms of stability, and (iii) we obtained a dynamical fit involving a counter-revolving configuration that is consistent with the observations of the HD73526 planetary system. In the present paper, we present and analyze data reductions assuming counter-revolving configurations for eight compact multi-planetary systems detected through the radial velocity method. In each case, we select the best fit leading to a dynamically stable solution. The resulting data reductions obtained in rms and chi values for counter-revolving configurations are of the same order, and sometimes slightly better, than for prograde configurations. In the end, these fits tend to show that, over the eight studied multi-planetary system...

Gayon-Markt, Julie

2009-01-01T23:59:59.000Z

96

Multianode cylindrical proportional counter for high count rates  

DOE Patents (OSTI)

A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (<60 keV) at count rates of greater than 10.sup.5 counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Hanson, James A. (Madison, WI); Kopp, Manfred K. (Oak Ridge, TN)

1981-01-01T23:59:59.000Z

97

Multianode cylindrical proportional counter for high count rates  

DOE Patents (OSTI)

A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (< 60 keV) at count rates of greater than 10/sup 5/ counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Hanson, J.A.; Kopp, M.K.

1980-05-23T23:59:59.000Z

98

MHK Technologies/Sub Surface Counter Rotation Current Generator | Open  

Open Energy Info (EERE)

Sub Surface Counter Rotation Current Generator Sub Surface Counter Rotation Current Generator < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Sub Surface Counter Rotation Current Generator.jpg Technology Profile Primary Organization Cyclocean LLC Technology Type Click here Axial Flow Turbine Technology Readiness Level Click here TRL 7 8 Open Water System Testing Demonstration and Operation Technology Description Self regulated sub surface current generators that operate independently that tether freely anchored offshore in deep waters in the Gulf Stream Current producing continuos clean energy for the eastern seaboard Technology Dimensions Device Testing Date Submitted 20:10.1 << Return to the MHK database homepage Retrieved from "http://en.openei.org/w/index.php?title=MHK_Technologies/Sub_Surface_Counter_Rotation_Current_Generator&oldid=681657

99

Introduction to Neutron Coincidence Counter Design Based on Boron-10  

SciTech Connect

The Department of Energy Office of Nonproliferation Policy (NA-241) is supporting the project 'Coincidence Counting With Boron-Based Alternative Neutron Detection Technology' at Pacific Northwest National Laboratory (PNNL) for development of an alternative neutron coincidence counter. The goal of this project is ultimately to design, build and demonstrate a boron-lined proportional tube based alternative system in the configuration of a coincidence counter. This report, providing background information for this project, is the deliverable under Task 1 of the project.

Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Siciliano, Edward R.

2012-01-22T23:59:59.000Z

100

Using DMA for copying performance counter data to memory  

SciTech Connect

A device for copying performance counter data includes hardware path that connects a direct memory access (DMA) unit to a plurality of hardware performance counters and a memory device. Software prepares an injection packet for the DMA unit to perform copying, while the software can perform other tasks. In one aspect, the software that prepares the injection packet runs on a processing core other than the core that gathers the hardware performance data.

Gara, Alan; Salapura, Valentina; Wisniewski, Robert W

2013-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

Proton-induced fission of heavy nuclei at intermediate energies  

E-Print Network (OSTI)

The intermediate energy proton-induced fission of 241Am, 238$U and 237$Np is studied. The inelastic interactions of protons and heavy nuclei are described by a CRISP model, in which the reaction proceeds in two steps. The first one corresponds fast cascade, where a series of individual particle-particle collisions occurs within the nucleus. It leaves a highly excited cascade residual nucleus, assumed to be in thermal equilibrium. Subsequently, in the second step the excited nucleus releases its energy by evaporation of neutrons and light charged particles as well. Both the symmetric and asymmetric fission are regarded, and the fission probabilities are obtained from CRISP code calculations, by means of statistical weighting factors. The fission cross sections, the fissility of the fissioning nuclei, and the number of nucleons lost by the target - before and after fission - are calculated and compared to experiments for 660 MeV protons incident on 241Am, 238$U and 237$Np. Some of the model predictions are in full compliance to the experiments. We conclude that our two step model provides a reasonable description of the medium energy proton-induced fission.

A. Deppman; E. Andrade-II; V. Guimaraes; G. S. Karapetyan; A. R. Balabekyan; N. A. Demekhina

2013-02-09T23:59:59.000Z

102

The Accretion of Ice Particles by Rime during Dry Growth  

Science Conference Proceedings (OSTI)

Freezing nuclei were used as tracers in experiments to determine whether ice particles are accreted by rime during dry growth. Experiments were conducted in a wind tunnel and in natural clouds at a mountaintop observatory. The results in both ...

Terry Deshler

1985-01-01T23:59:59.000Z

103

Temperature-Dependent Fission Barriers of Superheavy Nuclei  

E-Print Network (OSTI)

The dependence of fission barriers on the excitation energy of the compound nucleus impacts the survival probability of superheavy nuclei synthesized in heavy-ion fusion reactions. We study the temperature-dependent fission barriers by means of the self-consistent nuclear density functional theory. The equivalence of isothermal and isentropic descriptions is demonstrated. The effect of the particle gas is found to be negligible in the range of temperatures studied. Calculations have been carried out for $^{264}$Fm, $^{272}$Ds, $^{278}$112, $^{292}$114, and $^{312}$124. For nuclei around $^{278}$112 produced in "cold fusion" reactions, we predict a more rapid decrease of fission barriers with temperature as compared to the nuclei around $^{292}$114 synthesized in "hot fusion" experiments. This is explained in terms of the difference between the ground-state and fission-barrier temperatures. Our calculations are consistent with the long survival probabilities of the superheavy elements produced in Dubna with th...

Pei, J C; Sheikh-Javid, A; Kerman, A K

2009-01-01T23:59:59.000Z

104

Microscopic description of isoscalar giant resonance excitations in ??Ca and ¹¹?SN nuclei  

E-Print Network (OSTI)

This thesis presents a microscopic description of isoscalar giant resonance excitations in ??Ca and ¹¹? Sn nuclei within the self-consistent Skyrme-Hartree-Fock-Random-Phase-Approximation (HF-RPA) theory. Such characteristic features of the Isoscalar Giant Resonance as strength function, transition density and cross-sections for ??Ca and ¹¹?Sn nuclei are obtained. In this analysis, the SL1 Skyrme interaction associated with 230 MeV for the value of nuclear matter incompressibility coefficient K is chosen. The selection of nuclei is based on the availability of recent experimental results from Texas A&M University. The coordinate space formulation of the RPA in terms of Green's function is employed to obtain isoscalar monopole and dipole transition strength distributions for ??Ca and ¹¹?Sn nuclei. Calculations are performed with the discretized single-particle continuum. Theoretical transition strength distributions are used to find quantities of interest such as energy positions of resonance states, sum rules and average resonance energies. The cross-section of 240 MeV ?-particle scattering on the above nuclei are analysed within the Distorted Wave Born Approximation (DWBA) using transition densities obtained from the HF-RPA calculations. From this analysis the cross-sections for ISGDR excitations are obtained and compared with the recent experimental data obtained at the Cyclotron Institute, Texas A&M University.

Karki, Bhishma

2000-01-01T23:59:59.000Z

105

Nuclei embedded in an electron gas  

E-Print Network (OSTI)

The properties of nuclei embedded in an electron gas are studied within the relativistic mean-field approach. These studies are relevant for nuclear properties in astrophysical environments such as neutron-star crusts and supernova explosions. The electron gas is treated as a constant background in the Wigner-Seitz cell approximation. We investigate the stability of nuclei with respect to alpha and beta decay. Furthermore, the influence of the electronic background on spontaneous fission of heavy and superheavy nuclei is analyzed. We find that the presence of the electrons leads to stabilizing effects for both $\\alpha$ decay and spontaneous fission for high electron densities. Furthermore, the screening effect shifts the proton dripline to more proton-rich nuclei, and the stability line with respect to beta decay is shifted to more neutron-rich nuclei. Implications for the creation and survival of very heavy nuclear systems are discussed.

Thomas J. Buervenich; Igor N. Mishustin; Walter Greiner

2007-06-11T23:59:59.000Z

106

Spectroscopy of Neutron-rich Pu Nuclei  

Science Conference Proceedings (OSTI)

Spectroscopic studies of nuclei in the A{approx}250, Z{approx}100 region provide critical input to theoretical models that attempt to describe the structure and stability of the heaviest elements. We report here on new spectroscopic studies in the N = 150,151 nuclei {sup 244,245}Pu. (Z = 94). Excitations in these nuclei on the neutron-rich side of the valley of stability, accessed via inelastic and transfer reactions, complement fusion-evaporation studies of Z{>=}100 nuclei. States in {sup 244,245}Pu were populated using {sup 47}Ti and {sup 208}Pb beams incident on a {sup 244}Pu target, with delayed and prompt gamma rays detected by the Gammasphere array. The new results are discussed in the context of emerging systematics of one- and two-quasiparticle excitations in N{>=}150 nuclei.

Chowdhury, P.; Hota, S.; Lakshmi, S.; Tandel, S. K.; Harrington, T.; Jackson, E.; Moran, K.; Shirwadkar, U. [Department of Physics, University of Massachusetts Lowell, Lowell MA 01854 (United States); Ahmad, I.; Carpenter, M. P.; Greene, J.; Hoffman, C. R.; Janssens, R. V. F.; Khoo, T. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; McCutchan, E. A.; Seweryniak, D.; Stefanescu, I. [Argonne National Laboratory, Argonne, IL 60439 (United States)

2011-10-28T23:59:59.000Z

107

Quasifree Kaon Photoproduction on Nuclei  

E-Print Network (OSTI)

Investigations of the quasifree reaction A$(\\gamma, K Y)$B are presented in the distorted wave impulse approximation (DWIA). For this purpose, we present a revised tree-level model of elementary kaon photoproduction that incorporates hadronic form factors consistent with gauge invariance, uses SU(3) values for the Born couplings and uses resonances consistent with multi-channel analyses. The potential of exclusive quasifree kaon photoproduction on nuclei to reveal details of the hyperon-nucleus interaction is examined. Detailed predictions for the coincidence cross section, the photon asymmetry, and the hyperon polarization and their sensitivities to the ingredients of the model are obtained for all six production channels. Under selected kinematics these observables are found to be sensitive to the hyperon-nucleus final state interaction. Some polarization observables are found to be insensitive to distortion effects, making them ideal tools to search for possible medium modifications of the elementary amplitude.

F. X. Lee; T. Mart; C. Bennhold; H. Haberzettl; L. E. Wright

1999-07-30T23:59:59.000Z

108

SEARCH FOR CHARGED PARTICLES WITH REST MASS BETWEEN THAT OF THE ELECTRON AND MU-MESON  

SciTech Connect

An attempt was made to produce charged particles with rest mass between that of the electron and mu meson (hereafter called submuons) by electromagnetic pair pronduction from C nuclei. The incident photon beam was obtained by bombarding a thick C block with an 800-Mev electron beam. The same block served as the target for the production process. Only one member of the produced pair was to be observed. The momentum of the secondary particles (300 Mev/c) was determined by a zero-dispersion, doublefocusing magnetic spectrometer. The particles traversing the spectrometer were detected by a 6-courter telescope, in which the counters were separated by various thicknesses of lead. The signals from the counters were put in coincidence in a 6-channel fast-resolution coincidence circuit. The telescope was sensitive to submuons with rest masses between 175 and 10 electron masses. The expected counting rates were calculated using the Bethe-Heitler and Pauli-Weisskopf formulas for spin 1/2 and spin 0 submuons, respectively. An integration over the variables of the unobserved member of the pair, and thus over the momentum transfer to the C nucleus was performed. The nucleus was treated by a sum rale calculation to take into account both the finite nuclear size and the elastic and inelastic contributions to the cross section. The resulting cross sections were multiplied by the total photon spectrum and the results integrated over the available photon energy. The total photon spectrum included both the real photon spectrum from electron bremsstrshlung in the C target and the virtual photon spectrum associated with the electrons themselves. The expected courting rates varied from 70 to 12,500 counts per l0t7 incident electrons for spin 1/2 submuons with rest masses between 175 and 25 electron masses and half lives in the microsecond region or longer. The similar rates for spin 0 submuons were 10 to 2870 counts. Since only 4.10 plus or minus 2.05 counts per 10/sup 17/ incident electrons were observed, it seems highly unlikely thai particles with rest mass between that of the electron and mu-meson exist. (M.P.G.)

Coward, D.H.

1963-01-01T23:59:59.000Z

109

NUCLEI: Nuclear Computational Low-Energy Initiative | Argonne...  

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

NUCLEI: Nuclear Computational Low-Energy Initiative NUCLEI: Nuclear Computational Low-Energy Initiative This project seeks to advance large-scale nuclear physics compoutations in...

110

Coupled-cluster computations of atomic nuclei  

E-Print Network (OSTI)

In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors.

G. Hagen; T. Papenbrock; M. Hjorth-Jensen; D. J. Dean

2013-12-30T23:59:59.000Z

111

A Combined Neutron and Gamma-Ray Multiplicity Counter Based on Liquid Scintillation Detectors  

Science Conference Proceedings (OSTI)

Multiplicity counters for neutron assay have been extensively used in materials control and accountability for nonproliferation and nuclear safeguards. Typically, neutron coincidence counters are utilized in these fields. In this work, we present a measurement system that makes use not only of neutron (n) multiplicity counting but also of gamma-ray (g) multiplicity counting and the combined higher-order multiples containing both neutrons and gamma rays. The benefit of this approach is in using both particle types available from the sample, leading to a reduction in measurement times needed when using more measurables. We present measurement results of n, g, nn, ng, gg, nnn, nng, ngg, and ggg multiples emitted by Mixed-Oxide (MOX) samples measured at Idaho National Laboratory (INL). The MOX measurement is compared to initial validation of the detection system done using a 252Cf source. The dual radiation measuring system proposed here uses extra measurables to improve the statistics when compared to a neutron-only system and allows for extended analysis and interpretation of sample parameters. New challenges such as the effect of very high intrinsic gamma-ray sources in the case of MOX samples is discussed. Successful measurements of multiples rates can be performed also when using high-Z shielding.

Andreas Enqvist; Marek Flaska; Jennifer Dolan; David L. Chichester; Sara A. Pozzi

2011-10-01T23:59:59.000Z

112

Water uptake of clay and desert dust aerosol particles at sub- and supersaturated water vapor conditions  

SciTech Connect

Airborne mineral dust particles serve as cloud condensation nuclei (CCN), thereby influencing the formation and properties of warm clouds. It is therefore of particular interest how dust aerosols with different mineralogy behave when exposed to high relative humidity (RH) or supersaturation with respect to liquid water similar to atmospheric conditions. In this study the sub-saturated hygroscopic growth and the supersaturated cloud condensation nucleus activity of pure clays and real desert dust aerosols was determined using a hygroscopicity tandem differential mobility analyzer (HTDMA) and a cloud condensation nuclei counter (CCNC), respectively. Five different illite, montmorillonite and kaolinite clay samples as well as three desert dust samples (Saharan dust (SD), Chinese dust (CD) and Arizona test dust (ATD)) were used. Aerosols were generated both with a wet and a dry disperser and the water uptake was parameterized via the hygroscopicity parameter, ?. The hygroscopicity of dry generated dust aerosols was found to be negligible when compared to processed atmospheric aerosols, with CCNC derived ? values between 0.00 and 0.02. The latter value can be idealized as a particle consisting of 96.7% (by volume) insoluble material and ~3.3% ammonium sulfate. Pure clay aerosols were found to be generally less hygroscopic than real desert dust particles. All illite and montmorillonite samples had ?~0.003, kaolinites were least hygroscopic and had ?=0.001. SD (?=0.023) was found to be the most hygroscopic dry-generated desert dust followed by CD (?=0.007) and ATD (?=0.003). Wet-generated dust showed an increased water uptake when compared to dry-generated samples. This is considered to be an artifact introduced by redistribution of soluble material between the particles while immersed in an aqueous medium during atomization, thus indicating that specification of the generation method is critically important when presenting such data. Any atmospheric processing of fresh mineral dust which leads to the addition of more than ~3% soluble material is expected to significantly enhance hygroscopicity and CCN activity.

Herich, Hanna; Tritscher, Torsten; Wiacek, Aldona; Gysel, Martin; Weingartner, E.; Lohmann, U.; Baltensperger, Urs; Cziczo, Daniel J.

2009-11-01T23:59:59.000Z

113

GAMMA PROPORTIONAL COUNTER CONTAINING HIGH Z GAS AND LOW Z MODERATOR  

DOE Patents (OSTI)

A gamma radiation counter employing a gas proportional counter is described. The radiation counter comprises a cylindrical gas proportional counter which contains a high atomic number gas and is surrounded by a low atomic number gamma radiation moderator material. At least one slit is provided in the moderator to allow accident gamma radiation to enter the moderator in the most favorable manner for moderation, and also to allow low energy gamma radiation to enter the counter without the necessity of passing through the moderator. This radiation counter is capable of detecting and measuring gamma radiation in the energy range of 0.5-5 Mev. (AEC)

Fox, R.

1963-07-23T23:59:59.000Z

114

Cooper pair transfer in nuclei  

E-Print Network (OSTI)

The second order DWBA implementation of two-particle transfer direct reactions which includes simultaneous and successive transfer, properly corrected by non-orthogonality effects is tested with the help of controlled nuclear structure and reaction inputs against data spanning the whole mass table, and showed to constitute a quantitative probe of nuclear pairing correlations.

G. Potel; A. Idini; F. Barranco; E. Vigezzi; R. A. Broglia

2013-04-09T23:59:59.000Z

115

Quasifree Eta Photoproduction from Nuclei  

E-Print Network (OSTI)

Quasifree $\\eta$ photoproduction from nuclei is studied in the Distorted Wave Impulse Approximation (DWIA). The elementary eta production operator contains Born terms, vector meson and nucleon resonance contributions and provides an excellent description of the recent low energy Mainz measurements on the nucleon. The resonance sector includes the $S_{11}(1535)$, $P_{11}(1440)$ and $D_{13}(1520)$ states whose couplings are fixed by independent electromagnetic and hadronic data. Different models for the $\\eta N$ t-matrix are used to construct a simple $\\eta A$ optical potential based on a $t \\rho$-approximation. We find that the exclusive $A(\\gamma,\\eta N)B$ process can be used to study medium modifications of the $N^*$ resonances, particularly if the photon asymmetry can be measured. The inclusive $A(\\gamma, \\eta)X$ reaction is compared to new data obtained on $^{12}C$, $^{40}Ca$, and is found to provide a clear distinction between different models for the $\\eta N$ t-matrix.

F. X Lee; L. E. Wright; C. Bennhold; L. Tiator

1996-01-03T23:59:59.000Z

116

Production-run software failure diagnosis via hardware performance counters  

Science Conference Proceedings (OSTI)

Sequential and concurrency bugs are widespread in deployed software. They cause severe failures and huge financial loss during production runs. Tools that diagnose production-run failures with low overhead are needed. The state-of-the-art diagnosis techniques ... Keywords: concurrency bugs, failure diagnosis, performance counters, production run

Joy Arulraj; Po-Chun Chang; Guoliang Jin; Shan Lu

2013-04-01T23:59:59.000Z

117

Countering DoS attacks with stateless multipath overlays  

Science Conference Proceedings (OSTI)

Indirection-based overlay networks (IONs) are a promising approach for countering distributed denial of service (DDoS) attacks. Such mechanisms are based on the assumption that attackers will attack a fixed and bounded set of overlay nodes causing service ... Keywords: key agreement, spread-spectrum communications

Angelos Stavrou; Angelos D. Keromytis

2005-11-01T23:59:59.000Z

118

Boron-Lined Multitube Neutron Proportional Counter Test  

Science Conference Proceedings (OSTI)

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride (BF3)-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated non-scintillating plastic fibers. In addition, a few other companies have detector technologies that might be competitive in the near term as an alternative technology. Reported here are the results of tests of a boron-lined, “multitube” proportional counter manufactured by Centronic Ltd. (Surry, U.K. and Houston, TX). This testing measured the required performance for neutron detection efficiency and gamma-ray rejection capabilities of the detector.

Woodring, Mitchell L.; Ely, James H.; Kouzes, Richard T.; Stromswold, David C.

2010-09-07T23:59:59.000Z

119

Fission Barriers of Compound Superheavy Nuclei  

E-Print Network (OSTI)

The dependence of fission barriers on the excitation energy of the compound nucleus impacts the survival probability of superheavy nuclei synthesized in heavy-ion fusion reactions. In this work, we investigate the isentropic ...

Sheikh, J. A.

120

Weighing exotic nuclei for nuclear astrophysics  

Science Conference Proceedings (OSTI)

We briefly discuss recent mass measurements of exotic nuclei performed with Penning trap and storage ring mass spectrometry. A special attention is given to results relevant for nuclear astrophysics.

Litvinov, Yuri A.; Blaum, Klaus [GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany) and Ruprecht-Karls-Universitaet Heidelberg, 69120 Heidelberg (Germany); Max Planck Institut fuer Kernphysik, 69117 Heidelberg (Germany) and Ruprecht-Karls-Universitaet Heidelberg, 69120 Heidelberg (Germany)

2012-11-12T23:59:59.000Z

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121

Heat capacity and pairing transition in nuclei  

E-Print Network (OSTI)

A simple model based on the canonical-ensemble theory is outlined for hot nuclei. The properties of the model are discussed with respect to the Fermi gas model and the breaking of Cooper pairs. The model describes well the experimental level density of deformed nuclei in various mass regions. The origin of the so-called S-shape of the heat capacity curve Cv(T) is discussed.

M. Guttormsen; M. Hjorth-Jensen; E. Melby; J. Rekstad; A. Schiller; S. Siem

2001-04-30T23:59:59.000Z

122

THE INFLUENCE OF INELASTIC NEUTRINO REACTIONS WITH LIGHT NUCLEI ON THE STANDING ACCRETION SHOCK INSTABILITY IN CORE-COLLAPSE SUPERNOVAE  

Science Conference Proceedings (OSTI)

We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability (SASI). The time evolution of shock waves is calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions, and alpha particles are taken into account in the hydrodynamical simulations. In addition, the effects of ordinary charged-current interactions with nucleons is addressed in the simulations. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as {approx}10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles are heated near the shock wave, which is important when the shock wave expands and the density and temperature of matter become low. It is also found that the models with heating by light nuclei evolve differently in the non-linear phase of SASI than do models that lack heating by light nuclei. This result is because matter in the gain region has a varying density and temperature and therefore sub-regions appear that are locally rich in deuterons and alpha particles. Although the light nuclei are never dominant heating sources and they work favorably for shock revival in some cases and unfavorably in other cases, they are non-negligible and warrant further investigation.

Furusawa, Shun; Nagakura, Hiroki; Yamada, Shoichi [Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Sumiyoshi, Kohsuke, E-mail: furusawa@heap.phys.waseda.ac.jp [Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan)

2013-09-01T23:59:59.000Z

123

Calibration of an ultra-low-background proportional counter for measuring 37 Ar  

Science Conference Proceedings (OSTI)

An ultra-low-background proportional counter design has been developed at Pacific Northwest National Laboratory (PNNL) using clean materials

2013-01-01T23:59:59.000Z

124

Particle injector for fluid systems  

DOE Patents (OSTI)

A particle injector device provides injection of particles into a liquid stream. The device includes a funnel portion comprising a conical member having side walls tapering from a top opening (which receives the particles) down to a relatively smaller exit opening. A funnel inlet receives a portion of the liquid stream and the latter is directed onto the side walls of the conical member so as to create a cushion of liquid against which the particles impact. A main section of the device includes an inlet port in communication with the exit opening of the funnel portion. A main liquid inlet receives the main portion of the liquid stream at high pressure and low velocity and a throat region located downstream of the main liquid inlet accelerates liquid received by this inlet from the low velocity to a higher velocity so as to create a low pressure area at the exit opening of the funnel portion. An outlet opening of the main section enables the particles and liquid stream to exit from the injector device. This invention is particularly concerned with particle injection in connection with the calibration of inline optical particle counters.

Ruch, J.F.

1996-12-31T23:59:59.000Z

125

Design and operation of a counter-rotating aspirated compressor blowdown test facility; Counter-rotating aspirated compressor blowdown test facility.  

E-Print Network (OSTI)

??A unique counter-rotating aspirated compressor was tested in a blowdown facility at the Gas Turbine Laboratory at MIT. The facility expanded on experience from previous… (more)

Parker, David V. (David Vickery)

2005-01-01T23:59:59.000Z

126

Stability and Production of Superheavy Nuclei  

E-Print Network (OSTI)

Beyond uranium heavy elements rapidly become increasingly unstable with respect to spontaneous fission as the proton number Z increases, because of the disruptive effect of the long-range Coulomb force. However, in the region just beyond Z = 100 magic proton and neutron numbers and the associated shell structure enhances nuclear stability sufficiently to allow observation of additional nuclei. Some thirty years ago it was speculated that an island of spherical, relatively stable superheavy nuclei would exist near the next doubly magic proton-neutron combination beyond 208:Pb, that is, at proton number Z = 114 and neutron number N = 184. Theory and experiment now show that there also exists a rock of stability in the vicinity of Z = 110 and N = 162 between the actinide region, which previously was the end of the peninsula of known elements, and the predicted island of spherical superheavy nuclei slightly southwest of the magic numbers Z = 114 and N = 184. We review here the stability properties of the heavy region of nuclei. Just as the decay properties of nuclei in the heavy region depend strongly on shell structure, this structure also dramatically affects the fusion entrance channel. The six most recently discovered new elements were all formed in cold-fusion reactions. We discuss here the effect of the doubly magic structure of the target in cold-fusion reactions on the fusion barrier and on dissipation.

Peter Moller; J. Rayford Nix

1997-09-08T23:59:59.000Z

127

QRPA Calculations for Spherical and Deformed Nuclei With the Gogny Force  

Science Conference Proceedings (OSTI)

Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed with the D1S Gogny force. Dipole responses have been calculated in Ne isotopes to study the existence of soft dipole modes in exotic nuclei. A comparison between QRPA and generator coordinate method with Gaussian overlap approximation results is done for low lying 2{sup +} states in N = 16 isotones and Ni isotopes.

Peru, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

2009-08-26T23:59:59.000Z

128

Particle separation  

DOE Patents (OSTI)

Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

Moosmuller, Hans (Reno, NV); Chakrabarty, Rajan K. (Reno, NV); Arnott, W. Patrick (Reno, NV)

2011-04-26T23:59:59.000Z

129

Chirality in odd-$A$ Rh isotopes within triaxial particle rotor model  

E-Print Network (OSTI)

Adopting the fully quantal triaxial particle rotor model, the candidate chiral doublet bands in odd-$A$ nuclei $^{103}$Rh and $^{105}$Rh with $\\pi g_{9/2}^{-1}\\otimes\

B. Qi; S. Q. Zhang; S. Y. Wang; J. Meng; T. Koike

2011-02-11T23:59:59.000Z

130

Probing the Structure of Halo Nuclei  

E-Print Network (OSTI)

Our understanding of halo nuclei has so far relied on high-energy scattering and reactions, but a number of uncertainties remain. I discuss in general terms the new range of observables which will be measured by experiments around the Coulomb barrier, and how some details of the reaction mechanisms still need to be clarified.

I. J. Thompson

1997-05-01T23:59:59.000Z

131

Coherent Dissociation of Relativistic $^{12}$N Nuclei  

E-Print Network (OSTI)

The dissociation of relativistic $^{12}$N nuclei having a momentum of 2 GeV/c per nucleon and undergoing the most peripheral interactions in a track emulsion is studied. The picture of charged topology of product ensembles of relativistic fragments and special features of their angular distributions are presented.

R. R. Kattabekov; K. Z. Mamatkulov; S. S. Alikulov; D. A. Artemenkov; R. N. Bekmirzaev; V. Bradnova; P. I. Zarubin; I. G. Zarubina; N. V. Kondratieva; N. K. Kornegrutsa; D. O. Krivenkov; A. I. Malakhov; K. Olimov; N. G. Peresadko; N. G. Polukhina; P. A. Rukoyatkin; V. V. Rusakova; R. Stanoeva; S. P. Kharlamov

2013-10-08T23:59:59.000Z

132

Thermodynamics of nuclei in thermal contact  

E-Print Network (OSTI)

The behaviour of a di-nuclear system in the regime of strong pairing correlations is studied with the methods of statistical mechanics. It is shown that the thermal averaging is strong enough to assure the application of thermodynamical methods to the energy exchange between the two nuclei in contact. In particular, thermal averaging justifies the definition of a nuclear temperature.

Karl-Heinz Schmidt; Beatriz Jurado

2010-10-05T23:59:59.000Z

133

Relationship Between Fog Condensation Nuclei and Fog Microstructure  

Science Conference Proceedings (OSTI)

Measurements of fog drop size distribution, cloud condensation nuclei and fog condensation nuclei were made at several locations along the U.S. Pacific Coast. Wide variations in fog microstructure were associated with and appeared to be mostly ...

James G. Hudson

1980-08-01T23:59:59.000Z

134

Design, construction and implementation of spherical tissue equivalent proportional counter  

E-Print Network (OSTI)

Tissue equivalent proportional counters (TEPC) are used for medical and space activities whenever a combination of high and low LET (lineal energy transfer) radiations are present. With the frequency and duration of space activities increasing, exposure to fast heavy ions from galactic cosmic radiation and solar events is a major concern. The optimum detector geometry is spherical; to obtain an isotropic response, but simple spherical detectors have the disadvantage of a non-uniform electric field. In order to achieve a uniform electric field along the detector axis, spherical tissue equivalent proportional counters have been designed with different structures to modify the electric field. Some detectors use a cylindrical coil that is coaxial with the anode, but they are not reliable because of their sensitivity to microphonic noise and insufficient mechanical strength. In this work a new spherical TEPC was developed. The approach used was to divide the cathode in several rings with different thicknesses, and adjust the potential difference between each ring and the anode to produce an electric field that is nearly constant along the length of the anode. A-150 tissue equivalent plastic is used for the detector walls, the insulator material between the cathode rings is low density polyethylene, and the gas inside the detector is propane. The detector, along with the charge sensitive preamplifier, is encased in a stainless steel vacuum chamber. The gas gain was found to be 497.5 at 782 volts and the response to neutrons as a function of angle was constant ±7%. This spherical tissue equivalent proportional counter detector system will improve the accuracy of dosimetry in space, and as a result improve radiation safety for astronauts.

Perez Nunez, Delia Josefina

2008-05-01T23:59:59.000Z

135

High-level neutron coincidence counter maintenance manual  

Science Conference Proceedings (OSTI)

High-level neutron coincidence counter operational (field) calibration and usage is well known. This manual makes explicit basic (shop) check-out, calibration, and testing of new units and is a guide for repair of failed in-service units. Operational criteria for the major electronic functions are detailed, as are adjustments and calibration procedures, and recurrent mechanical/electromechanical problems are addressed. Some system tests are included for quality assurance. Data on nonstandard large-scale integrated (circuit) components and a schematic set are also included.

Swansen, J.; Collinsworth, P.

1983-05-01T23:59:59.000Z

136

The influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability in core-collapse supernovae  

E-Print Network (OSTI)

We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability (SASI). The time evolution of shock waves is calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as 10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles are heated near the shock wave, which is important when the shock wave expands and the density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in the non-linear phase of SASI. This results is because matter in the gain region has a varying density and temperature and there appear sub-regions that are locally rich in deuterons and alpha particles. Although the light nuclei are never dominant heating sources and they work favorably for shock revival in some cases and unfavorably in other cases, they are non-negligible and warrant further investigation.

Shun Furusawa; Hiroki Nagakura; Kohsuke Sumiyoshi; Shoichi Yamada

2013-05-07T23:59:59.000Z

137

Photon parton distributions in nuclei and the EMC effect  

E-Print Network (OSTI)

Photons as well as quarks and gluons are constituents of the infinite momentum frame (IMF) wave function of an energetic particle. They are mostly equivalent photons whose amplitude follows from the Lorentz transformation of the particle rest frame Coulomb field into the IMF and from the conservation of the electromagnetic current. We evaluate in a model independent way the dominant photon contribution \\propto \\alpha_{em}(Z^2/A^{4/3})\\ln(1/R_{A}m_{N}x) to the nuclear structure functions as well as the term \\propto \\alpha_{em}Z/A. In addition we show that the definition of x consistent with the exact kinematics of eA scattering (with exact sum rules) works in the same direction as the nucleus field of equivalent photons. Combined, these effects account for the bulk of the EMC effect for x\\le 0.5 where Fermi motion effects are small. In particular for these x the hadronic mechanism contribution to the EMC effect does not exceed \\sim 3% for all nuclei. Also the A-dependence of the hadronic mechanism of the EMC effect for x > 0.5 is significantly modified.

Leonid Frankfurt; Mark Strikman

2010-09-24T23:59:59.000Z

138

Monolithic Active Pixel Matrix with Binary Counters (MAMBO) ASIC  

SciTech Connect

Monolithic Active Matrix with Binary Counters (MAMBO) is a counting ASIC designed for detecting and measuring low energy X-rays from 6-12 keV. Each pixel contains analogue functionality implemented with a charge preamplifier, CR-RC{sup 2} shaper and a baseline restorer. It also contains a window comparator which can be trimmed by 4 bit DACs to remove systematic offsets. The hits are registered by a 12 bit ripple counter which is reconfigured as a shift register to serially output the data from the entire ASIC. Each pixel can be tested individually. Two diverse approaches have been used to prevent coupling between the detector and electronics in MAMBO III and MAMBO IV. MAMBO III is a 3D ASIC, the bottom ASIC consists of diodes which are connected to the top ASIC using {mu}-bump bonds. The detector is decoupled from the electronics by physically separating them on two tiers and using several metal layers as a shield. MAMBO IV is a monolithic structure which uses a nested well approach to isolate the detector from the electronics. The ASICs are being fabricated using the SOI 0.2 {micro}m OKI process, MAMBO III is 3D bonded at T-Micro and MAMBO IV nested well structure was developed in collaboration between OKI and Fermilab.

Khalid, Farah F.; Deptuch, Grzegorz; Shenai, Alpana; Yarema, Raymond J.; /Fermilab

2010-11-01T23:59:59.000Z

139

Counter-Top Thermoacoustic Refrigerator- An Experimental Investigation  

SciTech Connect

Thermoacoustic phenomenon is a new alternative refrigeration technology. Though design and fabrication is complex for getting the desired effect, it is environmentally friendly and successful system showed that it is relatively easy to run compared to the traditional vapor compression refrigeration system. Currently, theories supporting the thermoacoustic refrigeration systems are yet to be comprehensive to make them commercially viable. Theoretical, experimental, and numerical studies are being done to address the thermodynamics-acoustics interactions. In this study, experimental investigations were completed to test the feasibility of the practical use of a thermoacoustic refrigerator in its counter-top form for future specific application. The system was designed and fabricated based on linear acoustic theory. Acoustic power was given by a loud speaker and thermoacoustic effects were measured in terms of the cooling effects produced at resonanance. Investigations showed that discrepancies between designed and working resonance frequency exist. Thermoacoutic cooling improved at a certain frequency, achieved when the working frequency was varied away from the design frequency. A cooling effect of 4.8 K below the ambient temperature of 23.3 deg. C was obtained from the counter-top thermoacoustic system. This system uses no refrigerants and no compressor to generate the cooling effect, a potential to be further investigated for a practical system.

Anwar, Mahmood; Ghazali, Normah Mohd [Department of Thermo-Fluids, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia Skudai 81310, Johor (Malaysia)

2010-06-28T23:59:59.000Z

140

Self-consistent Green's function method for nuclei and nuclear matter  

E-Print Network (OSTI)

Recent results obtained by applying the method of self-consistent Green's functions to nuclei and nuclear matter are reviewed. Particular attention is given to the description of experimental data obtained from the (e,e'p) and (e,e'2N) reactions that determine one and two-nucleon removal probabilities in nuclei since the corresponding amplitudes are directly related to the imaginary parts of the single-particle and two-particle propagators. For this reason and the fact that these amplitudes can now be calculated with the inclusion of all the relevant physical processes, it is useful to explore the efficacy of the method of self-consistent Green's functions in describing these experimental data. Results for both finite nuclei and nuclear matter are discussed with particular emphasis on clarifying the role of short-range correlations in determining various experimental quantities. The important role of long-range correlations in determining the structure of low-energy correlations is also documented. For a complete understanding of nuclear phenomena it is therefore essential to include both types of physical correlations. We demonstrate that recent experimental results for these reactions combined with the reported theoretical calculations yield a very clear understanding of the properties of {\\em all} protons in the nucleus. We propose that this knowledge of the properties of constituent fermions in a correlated many-body system is a unique feature of nuclear physics.

W. H. Dickhoff; C. Barbieri

2004-02-11T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

Proof Search and Counter-Model Construction for Bi-intuitionistic ...  

Science Conference Proceedings (OSTI)

directly support proof search. To describe a proof search procedure, we develop a more algorithmic version that also allows for counter-model extraction from a ...

142

Non-Newtonian gravity in finite nuclei  

E-Print Network (OSTI)

In this talk, we report our recent study of constraining the non-Newtonian gravity at femtometer scale. We incorporate the Yukawa-type non-Newtonian gravitational potential consistently to the Skyrme functional form using the exact treatment for the direct contribution and density-matrix expansion method for the exchange contribution. The effects from the non-Newtonian potential on finite nuclei properties are then studied together with a well-tested Skyrme force. Assuming that the framework without non-Newtonian gravity can explain the binding energies and charge radii of medium to heavy nuclei within 2% error, we set an upper limit for the strength of the non-Newtonian gravitational potential at femtometer scale.

Xu, Jun; Chen, Lie-Wen; Zheng, Hao

2012-01-01T23:59:59.000Z

143

AN ENGINE EXHAUST PARTICLE SIZERTM SPECTROMETER FOR TRANSIENT EMISSION PARTICLE MEASUREMENTS  

DOE Green Energy (OSTI)

There has been increased interest in obtaining size distribution data during transient engine operation where both particle size and total number concentrations can change dramatically. Traditionally, the measurement of particle emissions from vehicles has been a compromise based on choosing between the conflicting needs of high time resolution or high particle size resolution for a particular measurement. Currently the most common technique for measuring submicrometer particle sizes is the Scanning Mobility Particle Sizer (SMPSTM) system. The SMPS system gives high size resolution but requires an aerosol to be stable over a long time period to make a particle size distribution measurement. A Condensation Particle Counter (CPC) is commonly used for fast time response measurements but is limited to measuring total concentration only. This paper describes a new instrument, the Engine Exhaust Particle SizerTM (EEPSTM) spectrometer, which has high time resolution and a reasonable size resolution. The EEPS was designed specifically for measuring engine exhaust and, like the SMPS system, uses a measurement based on electrical mobility. Particles entering the instrument are charged to a predictable level, then passed through an annular space where they are repelled outward by the voltage from a central column. When the particles reach electrodes on the outer cylindrical (a column of rings), they create a current that is measured by an electrometer on one or more of the rings. The electrometer currents are measured multiple times per second to give high time resolution. A sophisticated realtime inversion algorithm converts the currents to particle size and concentration for immediate display.

Johnson, T; Caldow, R; Pucher, A; Mirme, A; Kittelson, D

2003-08-24T23:59:59.000Z

144

AN ENGINE EXHAUST PARTICLE SIZER{trademark} SPECTROMETER FOR TRANSIENT EMISSION PARTICLE MEASUREMENTS  

DOE Green Energy (OSTI)

There has been increased interest in obtaining size distribution data during transient engine operation where both particle size and total number concentrations can change dramatically. Traditionally, the measurement of particle emissions from vehicles has been a compromise based on choosing between the conflicting needs of high time resolution or high particle size resolution for a particular measurement. Currently the most common technique for measuring submicrometer particle sizes is the Scanning Mobility Particle Sizer (SMPSTM) system. The SMPS system gives high size resolution but requires an aerosol to be stable over a long time period to make a particle size distribution measurement. A Condensation Particle Counter (CPC) is commonly used for fast time response measurements but is limited to measuring total concentration only. This paper describes a new instrument, the Engine Exhaust Particle SizerTM (EEPSTM) spectrometer, which has high time resolution and a reasonable size resolution. The EEPS was designed specifically for measuring engine exhaust and, like the SMPS system, uses a measurement based on electrical mobility. Particles entering the instrument are charged to a predictable level, then passed through an annular space where they are repelled outward by the voltage from a central column. When the particles reach electrodes on the outer cylindrical (a column of rings), they create a current that is measured by an electrometer on one or more of the rings. The electrometer currents are measured multiple times per second to give high time resolution. A sophisticated realtime inversion algorithm converts the currents to particle size and concentration for immediate display.

Johnson, T: Caldow, R; Pucher, A Mirme, A Kittelson, D

2003-08-24T23:59:59.000Z

145

Light nuclei production in heavy ion collisions  

E-Print Network (OSTI)

Light nuclei production as a result of nuclear coalescence effect can give some signals on final state of Quark Gluon Plasma formation. We are studying the behavior of nuclear modification factor as a function of different variables using the simulated data coming from the FASTMC generator. This data is necessary to extract information on coalescence mechanism from experimental data on high energy nuclear-nuclear interactions.

K. H. Khan; M. K. Suleymanov; Z. Wazir; E. U. Khan; Mahnaz Q. Haseeb; M. Ajaz

2009-04-14T23:59:59.000Z

146

Particle Lifetimes  

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

Reviewing Particle Lifetimes Reviewing Particle Lifetimes The lifetimes of elementary particles are statistical in nature. In a given sample, one particle might decay immediately, another in 1 nanosecond, yet another after 10 milliseconds, and still another in 50 years. What we call the lifetime is the time it takes for a sample to decay so 1/e (~30%) of the sample is left; after 2 lifetimes, 1/e2 of the sample is left, and so on. Take, for example, a sample of cosmic ray muons produced in the upper atmosphere. These muons, when observed at (relative) rest in the laboratory, have a mean lifetime T. Now, since particle decay is statistical in nature, the number of undecayed particles after a given time is a negative exponential function: N(t) = No e-t/T where N(t) is the number of muons at time t, No is the initial number of

147

Interaction of eta mesons with nuclei  

E-Print Network (OSTI)

Back in the mid eighties, a new branch of investigation which was related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound by the strong interaction and later developed into an extensive experimental program to search for such unstable states as well as understand the underlying interaction via eta meson producing reactions. The vast literature of experimental as well as theoretical works which studied various aspects of eta producing reactions such as the $\\pi ^+$ $n$ $\\to \\eta p$, $p d \\to ^3$He $\\eta$, $p \\,^6$Li $\\to ^7$Be $\\eta$ and $\\gamma ^3$He $\\to \\eta$ X, to name a few, had but one objective in mind: to understand the eta - nucleon ($\\eta N$) and hence the $\\eta$-nucleus interaction which could explain the production data and confirm the existence of some $\\eta$-mesic nuclei. In spite of these efforts, there remain uncertainties in the knowledge of the $\\eta N$ and hence the $\\eta$-nucleus interaction. The present review is hence an attempt to bind together the findings in these works and draw some global and specific conclusions which can be useful for future explorations.

N. G. Kelkar; K. P. Khemchandani; N. J. Upadhyay; B. K. Jain

2013-06-12T23:59:59.000Z

148

Low-lying states of heavy nuclei within the nucleon pair approximation  

Science Conference Proceedings (OSTI)

In this article we perform systematic calculations on low-lying states of 33 nuclei with A=202-212, using the nucleon pair approximation of the shell model. We use a phenomenological shell-model Hamiltonian that includes single-particle energies, monopole and quadrupole pairing interactions, and quadrupole-quadrupole interactions. The building blocks of our model space include one J=4 valence neutron pair, and one J=4,6,8 valence proton pair, in addition to the usual S and D pairs. We calculate binding energies, excitation energies, electric quadrupole and magnetic dipole moments of low-lying states, and E2 transition rates between low-lying states. Our calculated results are reasonably consistent with available experimental data. The calculated quadrupole moments and magnetic moments, many of which have not yet been measured for these nuclei, are useful for future experimental measurements.

Xu, Z. Y.; Lei, Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhao, Y. M. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); CCAST, World Laboratory, P.O. Box 8730, Beijing 100080 (China); Xu, S. W.; Xie, Y. X. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Arima, A. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Science Museum, Japan Science Foundation, 2-1 Kitanomaru-koen, Chiyoda-ku, Tokyo 102-0091 (Japan)

2009-05-15T23:59:59.000Z

149

PARTICLE ACCELERATOR  

DOE Patents (OSTI)

A fixed-field alternating gradient accelerator for simultaneous acceleration of two particle beams in opposite directions is described. (T.R.H.)

Ohkawa, T.

1959-06-01T23:59:59.000Z

150

THE EFFECTS OF BETA-SPECTROMETER FOCUSING POWER ON THE END-WINDOW COUNTER EFFICIENCY  

SciTech Connect

The efficency dependence of end-window counters on specimen surface density at a relative solid angle 0.111 was determined with the aid of a 4 pi counter. The isotopes S/sup 35/, Cas/sup 45/, Co/sup 60/, Ce/sup 141/Tl/sup 204/ , and Y/sup 91/ were studied. (tr-auth)

Vasil' ev, I.A.; Petrazhak, K.A.

1959-01-01T23:59:59.000Z

151

Optimizing counter-terror operations: Should one fight fire with "fire" or "water"?  

Science Conference Proceedings (OSTI)

This paper deals dynamically with the question of how recruitment to terror organizations is influenced by counter-terror operations. This is done within an optimal control model, where the key state is the (relative) number of terrorists and the key ... Keywords: Counter-terror, Epidemic modeling, Optimal dynamic control, Terrorism

Jonathan P. Caulkins; Dieter Grass; Gustav Feichtinger; Gernot Tragler

2008-06-01T23:59:59.000Z

152

Single-ended counter-rotating radial turbine for space application  

DOE Patents (OSTI)

A single-ended turbine with counter-rotating blades operating with sodium as the working fluid. The single-ended, counter-rotating feature of the turbine results in zero torque application to a space platform. Thus, maneuvering of the platform is not adversely affected by the turbine. 4 figs.

Coomes, E.P.; Wilson, D.G.; Webb, B.J.; McCabe, S.J.

1987-05-13T23:59:59.000Z

153

Possibilistic clustering approach to trackless ring Pattern Recognition in RICH counters  

Science Conference Proceedings (OSTI)

The pattern recognition problem in Ring Imaging CHerenkov (RICH) counters concerns the identification of an unknown number of rings whose centers and radii are assumed to be unknown. In this paper we present an algorithm based on the possibilistic approach ... Keywords: 07.05.Mh, 29.40.Ka, 29.85.+c, Pattern recognition, Possibilistic clustering, RICH counters

A. M. Massone; L. Studer; F. Masulli

2006-02-01T23:59:59.000Z

154

Performance confirmation of the Belle II imaging Time Of Propogation (iTOP) prototype counter  

SciTech Connect

The Bell Detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider performed extremely well, logging an integrated luminosity an order of magnitude higher than the design baseline. With this inverse attobarn of integrated luminosity, time-dependent CP-violation inn the 3rd generation beauty quarks was firmly established, and is now a precision measurement. Going beyond this to explore if the Kobayashi-Maskawa mechanism is the only contributor to quark-mixing, and to interrogate the flavor sector for non-standard model enhancements, requires a detector and accelerator capable of topping this world-record luminosity by more than an order of magnitude. The Belle II detector at the upgraded Super-KEKB accelerator has been designed to meet this highly ambitious goal of operating at a luminosity approaching 10{sup 36} cm{sup -2} s{sup -1}. Such higher event rates and backgrounds require upgrade of essentially all detector subsystems, as well as their readout. Comparing the Belle composite (threshold Aerogel + Time of Flight) particle identification (PID) system with the DIRC employed by BaBar, quartz radiator internal Cherenkov photon detection proved to have higher kaon efficiency and lower pion fake rates. However, because the detector structure and CsI calorimeter will be retained, an improved barrel PID must fit within a very narrow envelope, as indicated in Figure 1. To effectively utilize this space, a more compact detector concept based on the same quartz radiators, but primarily using photon arrival time was proposed. This Time Of Propagation (TOP) counter was studied in a number of earlier prototype tests. Key to the necessary 10's of picosecond single-photon timing has been the development of the so-called SL-10 Micro-Channel Plate Photo-Multiplier Tube (MCP-PMT), which has demonstrated sub-40 ps single photon Transit Time Spread TTS. Further simulation study of this detector concept indicated that a focusing mirror in the forward direction, as well as a modest image expansion volume and more highly pixelated image plane improve the theoretical detector performance, since timing alone is limited by chromatic dispersion of the Cherenkov photons. This imaging-TOP (or iTOP) counter is the basis of Belle II barrel PID upgrade. However, a number of critical performance parameters must be demonstrated prior to releasing this prototype design for production manufacture.

Schwartz, Alan; Liu, Yang; Belhorn, Matt; /Cincinnati U.; Browder, Thomas; Varner, Gary; Andrew, Matt; Rosen, Marc; Barrett, Matthew; Nishimura, Kurtis; Anderson, Eric /Hawaii U.; Iijima, Toru; /Nagoya U. /PNL, Richland

2011-10-17T23:59:59.000Z

155

Alpha-Particle Condensation in Nuclear Systems  

E-Print Network (OSTI)

The onset of quartetting, i.e. alpha-particle condensation, in symmetric nuclear matter is studied with the help of an in-medium modified four nucleon equation. It is found that at very low density quartetting wins over pairing, because of the strong binding of the alpha-particles. The critical temperature can reach values up to around 6 MeV. Also the disappearance of alpha-particles with increasing density, i.e. the Mott transition, is investigated. In finite nuclei the Hoyle state, that is the 0_2^+ of 12C, is identified as an "alpha-particle condensate" state. It is conjectured that such states also exist in heavier n alpha-nuclei, like 16O, 20Ne, etc. For instance the 6-th 0^+ state of 16O at 15.1 MeV is identified from a theoretical analysis as being a strong candidate for an alpha condensate state. Exploratory calculations are performed for the density dependence of the alpha condensate fraction at zero temperature to address the suppression of the four-particle condensate below nuclear-matter density. Possible quartet condensation in other systems is discussed briefly

Y. Funaki; T. Yamada; H. Horiuchi; G. Röpke; P. Schuck; A. Tohsaki

2008-09-03T23:59:59.000Z

156

Short-Distance Structure of Nuclei  

Science Conference Proceedings (OSTI)

One of Jefferson Lab's original missions was to further our understanding of the short-distance structure of nuclei. In particular, to understand what happens when two or more nucleons within a nucleus have strongly overlapping wave-functions; a phenomena commonly referred to as short-range correlations. Herein, we review the results of the (e,e'), (e,e'p) and (e,e'pN) reactions that have been used at Jefferson Lab to probe this short-distance structure as well as provide an outlook for future experiments.

Douglas Higinbotham, Eliazer Piasetzky, Stephen Wood

2011-06-01T23:59:59.000Z

157

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

158

y-scaling in Quasielastic Electron Scattering from Nuclei  

E-Print Network (OSTI)

A relativistic single particle model is used to calculate the inclusive $(e,e')$ reaction from $A=$12, 40, 56, 197, and 208 nuclei in the quasielastic region. We have shown that this model provides a very good description of the available experimental cross sections when they are dominated by the quasielastic process. In this paper we use this model to investigate the dependence of $y$-scaling on electron kinematics, particularly the electron scattering angle, for a range of squared four momentum transfer $0.20-0.80$ (GeV/c)$^2$. In this kinematic domain, Coulomb distortion of the electron does not significantly affect scaling, but final state interactions of the knocked out nucleon do affect scaling particularly when the nucleons have lower energies. In general, we find that scaling works for this reaction, but at lower values of the four momentum transfer, the scaling function does have some dependence on the electron scattering angle. We also consider a modification of y-scaling to include small binding energy effects as a function of Z and A and show that there is some improvement in scaling.

K. S. Kim; L. E. Wright

2007-05-01T23:59:59.000Z

159

Compressed Baryonic Matter: from Nuclei to Pulsars  

E-Print Network (OSTI)

Our world is wonderful because of the negligible baryonic part although unknown dark matter and dark energy dominate the Universe. Those nuclei in the daily life are forbidden to fuse by compression due to the Coulomb repulse, nevertheless, it is usually unexpected in extraterrestrial extreme-environments: the gravity in a core of massive evolved star is so strong that all the other forces (including the Coulomb one) could be neglected. Compressed baryonic matter is then produced after supernova, manifesting itself as pulsar-like stars observed. The study of this compressed baryonic matter can not only be meaningful in fundamental physics (e.g., the elementary color interaction at low-energy scale, testing gravity theories, detecting nano-Hertz background gravitational waves), but has also profound implications in engineering applications (including time standard and navigation), and additionally, is focused by Chinese advanced telescopes, either terrestrial or in space. Historically, in 1930s, L. Landau speculated that dense matter at supra-nuclear density in stellar cores could be considered as gigantic nuclei (the prototype of standard model of neutron star), however, we address that the residual compact object of supernova could be of condensed matter of quark clusters. The idea that pulsars are quark-cluster stars was not ruled out during the last decade, and we are expecting to test further by future powerful facilities. (in Chinese)

Renxin Xu

2013-10-12T23:59:59.000Z

160

The Stellar Populations of Seyfert 2 Nuclei  

E-Print Network (OSTI)

We present a preliminary analysis of the stellar populations in the central parsecs of a sample of 22 Seyfert 2 galaxies, based on a careful separation of nebular emission and stellar light in high-spatial resolution HST-STIS spectra. 10% of the surveyed nuclei display stellar populations of intermediate age, 1-2 Gyr old, whereas the remaining targets appear to be evenly split between objects showing only very old stellar populations and nuclei requiring also an additional blue featureless component, which we characterise by means of very young, few-Myr-old stars. The small fraction of stellar population of intermediate age seems to argue against the presence of such a young component, however, since the short lifetime of O-stars would imply recurrent star-formation episodes and the build-up over the last 1-2 Gyr of a detectable intermediate-age population. Additionally, a correlation between the luminosity of such a blue component and the emission from highly-ionised species, together with the general absence of Wolf-Rayet features, further suggests that the featureless continuum arises from the central engine rather than from star-forming regions. We discuss our results in the framework of the unification paradigm and of models for star formation close to supermassive black holes.

Marc Sarzi; Joe Shields; Rick Pogge; Paul Martini

2007-03-30T23:59:59.000Z

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


161

Spin Modes in Nuclei and Nuclear Forces  

SciTech Connect

Spin modes in stable and unstable exotic nuclei are studied and important roles of tensor and three-body forces on nuclear structure are discussed. New shell model Hamiltonians, which have proper tensor components, are shown to explain shell evolutions toward drip-lines and spin properties of both stable and exotic nuclei, for example, Gamow-Teller transitions in {sup 12}C and {sup 14}C and an anomalous M1 transition in {sup 17}C. The importance and the necessity of the repulsive monopole corrections in isospin T = 1 channel to the microscopic two-body interactions are pointed out. The corrections are shown to lead to the proper shell evolutions in neutron-rich isotopes. The three-body force, in particular the Fujita-Miyazawa force induced by {Delta} excitations, is pointed out to be responsible for the repulsive corrections among the valence neutrons. The important roles of the three-body force on the energies and transitions in exotic oxygen and calcium isotopes are demonstrated.

Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan) and Center for Nuclear Study, University of Tokyo, Hirosawa, Wako-shi, Saitama, 351-0198 (Japan); Otsuka, Takaharu [Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-05-06T23:59:59.000Z

162

Resonant Tidal Disruption in Galactic Nuclei  

E-Print Network (OSTI)

It has recently been shown that the rate of angular momentum relaxation in nearly-Keplerian star clusters is greatly increased by a process termed resonant relaxation (Rauch & Tremaine 1996), who also argued that tidal disruption of stars in galactic nuclei containing massive black holes could be noticeably enhanced by this process. We describe here the results of numerical simulations of resonant tidal disruption which quantitatively test the predictions made by Rauch & Tremaine. The simulation method is based on an N-body routine incorporating cloning of stars near the loss cone and a semi-relativistic symplectic integration scheme. We also briefly describe the discovery of chaos in the Wisdom-Holman symplectic integrator applied to highly eccentric orbits and propose a modified integration scheme that remains robust under these conditions. We find that resonant disruption rates exceed their non-resonant counterparts by an amount consistent with the predictions; in particular, we estimate the net tidal disruption rate for a fully resonant cluster to be about twice that of its non-resonant counterpart. No significant enhancement in rates is observed outside the critical radius. Relativistic quenching of the effect is found to occur for hole masses M>8*10^7 solar masses. The numerical results combined with the observed properties of galactic nuclei indicate that for most galaxies the resonant enhancement to tidal disruption rates will be very small.

Kevin P. Rauch; Brian Ingalls

1997-10-24T23:59:59.000Z

163

Binding energy and fission of the heavy charged massive particle - nucleus bound state  

E-Print Network (OSTI)

We consider a possibility of capture of a heavy charged massive particle $\\chi^-$ by the nucleus leading to appearance of a bound state. A simple analytic formula allowing to calculate binding energies of the $N\\chi^-$ bound state for different nuclei is derived. If the binding energy is sufficiently large the particle $\\chi^-$ is stable inside the nucleus. The probabilities of the nuclear fissions for such states are calculated. It is shown that the bound states are more stable to a possible fission in comparison to the bare nucleus. This makes an observation of this hypothetical charged massive particle and the superheavy nuclei more probable.

V. V. Flambaum; G. McManus; S. G. Porsev

2010-08-20T23:59:59.000Z

164

The Particle Adventure | Particle decays and annihiliations ...  

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

virtual particles. Virtual particles do not violate the conservation of energy. The kinetic energy plus mass of the initial decaying particle and the final decay products is...

165

The Particle Adventure | Accelerators and Particle Detectors  

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

Waves and particles The world's meterstick Mass and energy Energy-mass conversion Accelerators How to obtain particles to accelerate Accelerating particles Accelerating...

166

Online Particle Physics Information - Particles & Properties...  

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

Particles & Properties Data Review of Particle Physics (RPP) A biennial comprehensive review summarizing much of the known data about the field of particle physics produced by the...

167

Review of Particle Physics  

E-Print Network (OSTI)

11. Particle Physics Education Sites . . . . . . . . .ONLINE PARTICLE PHYSICS INFORMATION 1.11. Particle Physics Education Sites . . . . . . . . . . 12.

Nakamura, Kenzo

2010-01-01T23:59:59.000Z

168

Real-time multi-mode neutron multiplicity counter  

DOE Patents (OSTI)

Embodiments are directed to a digital data acquisition method that collects data regarding nuclear fission at high rates and performs real-time preprocessing of large volumes of data into directly useable forms for use in a system that performs non-destructive assaying of nuclear material and assemblies for mass and multiplication of special nuclear material (SNM). Pulses from a multi-detector array are fed in parallel to individual inputs that are tied to individual bits in a digital word. Data is collected by loading a word at the individual bit level in parallel, to reduce the latency associated with current shift-register systems. The word is read at regular intervals, all bits simultaneously, with no manipulation. The word is passed to a number of storage locations for subsequent processing, thereby removing the front-end problem of pulse pileup. The word is used simultaneously in several internal processing schemes that assemble the data in a number of more directly useable forms. The detector includes a multi-mode counter that executes a number of different count algorithms in parallel to determine different attributes of the count data.

Rowland, Mark S; Alvarez, Raymond A

2013-02-26T23:59:59.000Z

169

Counter flow cooling drier with integrated heat recovery  

DOE Patents (OSTI)

A drier apparatus for removing water or other liquids from various materials includes a mixer, drying chamber, separator and regenerator and a method for use of the apparatus. The material to be dried is mixed with a heated media to form a mixture which then passes through the chamber. While passing through the chamber, a comparatively cool fluid is passed counter current through the mixture so that the mixture becomes cooler and drier and the fluid becomes hotter and more saturated with moisture. The mixture is then separated into drier material and media. The media is transferred to the regenerator and heated therein by the hot fluid from the chamber and supplemental heat is supplied to bring the media to a preselected temperature for mixing with the incoming material to be dried. In a closed loop embodiment of the apparatus, the fluid is also recycled from the regenerator to the chamber and a chiller is utilized to reduce the temperature of the fluid to a preselected temperature and dew point temperature.

Shivvers, Steve D. (Prole, IA)

2009-08-18T23:59:59.000Z

170

Esplorazione Della Terra Incognita Della Fisica Nucleare: Nuclei Con Alone, Nuclei "A Grappoli", Nuclei Borromeani e Altre Stranezze Esotiche!  

E-Print Network (OSTI)

English: If the current status of theoretical and experimental knowledge in Nuclear Physics could be reduced to a geographical chart or a planisphere, then our epoch would be in some respect comparable to the end of the Medieval age and in other to the beginning of the Reinassance: epochs in which, together with the consolidated knowledge of the Old World, there have been great and revolutionary expeditions as the discovery of America or the periplus of Cape of Good Hope, explorations aimed at reaching the limits that, along the centuries, have lead to more and more engaging scientific discoveries in more and more far away lands, ending only in the twentieth century with the complete mapping of all the continents. Nuclear Physics is living an analogous adventure on the plane of contrast... - Italian: Se lo stato attuale delle conoscenze teoriche e sperimentali della Fisica Nucleare si potesse ridurre a una carta geografica o un mappamondo, allora la nostra epoca si potrebbe paragonare per certi versi alla fine del Medioevo e per altri al Rinascimento: epoche in cui, accanto alla conoscenza consolidata del Vecchio mondo, ci furono grandi e rivoluzionarie spedizioni come la scoperta dell'America o il periplo del Capo di Buona Speranza, esplorazioni geografiche volte al raggiungimento dei limiti che, nel corso dei secoli, hanno portato a scoperte scientifiche sempre pi\\`u avvincenti in terre sempre pi\\`u lontane, culminate solo nel ventesimo secolo con la completa mappatura di tutte le terre emerse. La Fisica Nucleare sta vivendo un'avventura analoga sul piano della contrapposizione tra la conoscenza acquisita sui nuclei stabili e la scoperta delle sorprendenti propriet\\`a esotiche dei nuclei instabili, pi\\`u difficili da produrre, da studiare e da comprendere.

Lorenzo Fortunato

2011-04-04T23:59:59.000Z

171

Elementary Particles  

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

Elementary Particles Elementary Particles Elementary Particles Detectors Accelerators Visit World Labs For Children - for younger people Electric Forces & Fields For Children The Electric Force For Children Electric Force Fields For Children Charges and Fields For Children Vibrating Charges and Electromagnetic Waves Electrons For Older People The Discovery of the Electron Traveling Waves For Older People Waves and Wave-Like Motion For Children Catch the Wave For Children Vibrating Charges and Electromagnetic Waves For Children Electromagnetic Waves Standing Waves For Older People Physics 128 Lecture Standing Waves For Older People Resonance in Strings and Springs For Older People Standing Wave - 1st Harmonic For Older People Standing Wave - 2nd Harmonic Atom For Older People Bohr Atom

172

Trillion Particles,  

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

Trillion Trillion Particles, 120,000 cores, and 350 TBs: Lessons Learned from a Hero I/O Run on Hopper Surendra Byna ∗ , Andrew Uselton ∗ , Prabhat ∗ , David Knaak † , and Yun (Helen) He ∗ ∗ Lawrence Berkeley National Laboratory, USA. Email: {sbyna, acuselton, prabhat, yhe}@lbl.gov † Cray Inc., USA. Email: knaak@cray.com Abstract-Modern petascale applications can present a variety of configuration, runtime, and data management challenges when run at scale. In this paper, we describe our experiences in running VPIC, a large-scale plasma physics simulation, on the NERSC production Cray XE6 system Hopper. The simulation ran on 120,000 cores using ∼80% of computing resources, 90% of the available memory on each node and 50% of the Lustre scratch file system. Over two trillion particles were simulated for 23,000 timesteps, and 10 one-trillion particle dumps, each ranging between

173

Carbon particles  

DOE Patents (OSTI)

A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

Hunt, Arlon J. (Oakland, CA)

1984-01-01T23:59:59.000Z

174

Oriented collisions for cold synthesis of superheavy nuclei  

E-Print Network (OSTI)

The conditions of optimum orientations (lowest barrier and largest interaction radius) for deformed colliding nuclei are introduced in "cold" fusion of superheavy nuclei. Also, the role of (octupole and) hexadecupole deformations is studied. We have used the proximity potential and applied our method to Ca-induced reactions.

Raj K. Gupta; M. Balasubramaniam; Rajesh Kumar; Narinder Singh

2003-07-12T23:59:59.000Z

175

On single nucleon wave functions in nuclei  

Science Conference Proceedings (OSTI)

The strong and singular interaction between nucleons, makes the nuclear many body theory very complicated. Still, nuclei exhibit simple and regular features which are simply described by the shell model. Wave functions of individual nucleons may be considered just as model wave functions which bear little resemblance to the real ones. There is, however, experimental evidence for the reality of single nucleon wave functions. There is a simple method of constructing such wave functions for valence nucleons. It is shown that this method can be improved by considering the polarization of the core by the valence nucleon. This gives rise to some rearrangement energy which affects the single valence nucleon energy within the nucleus.

Talmi, Igal [Weizamnn Institute of Science, Rehovot 76100 (Israel)

2011-05-06T23:59:59.000Z

176

Subthreshold Photofission of Even-Even Nuclei  

Science Conference Proceedings (OSTI)

Within quantum-mechanical fission theory, the angular distributions of fragments originating from the subthreshold photofission of the even-even nuclei {sup 232}Th, {sup 234}U, {sup 236}U, {sup 238}U, {sup 238}Pu, {sup 240}Pu, and {sup 242}Pu are analyzed for photon energies below 7 MeV. Special features of various fission channels are assessed under the assumption that the fission barrier has a two-humped shape. It is shown that the maximum value of the relative orbital angular momentum L{sub m} of fission fragments can be found upon taking into account deviations from the predictions of A. Bohr's formula for the angular distributions of fission fragments. The result is L{sub m} {approx_equal} 30. The existence of an 'isomeric shelf' for the angular distributions of fragments from {sup 236}U and {sup 238}U photofission in the low-energy region is confirmed.

Kadmensky, S.G.; Rodionova, L.V. [Voronezh State University, Universitetskaya pl. 1, Voronezh, 394693 (Russian Federation)

2005-09-01T23:59:59.000Z

177

Cluster magnetic fields from active galactic nuclei  

E-Print Network (OSTI)

Active galactic nuclei (AGN) found at the centers of clusters of galaxies are a possible source for weak cluster-wide magnetic fields. To evaluate this scenario, we present 3D adaptive mesh refinement MHD simulations of a cool-core cluster that include injection of kinetic, thermal, and magnetic energy via an AGN-powered jet. Using the MHD solver in FLASH 2, we compare several sub-resolution approaches that link the estimated accretion rate as measured on the simulation mesh to the accretion rate onto the central black hole and the resulting feedback. We examine the effects of magnetized outflows on the accretion history of the black hole and discuss the ability of these models to magnetize the cluster medium.

Sutter, P M; Yang, H -Y

2009-01-01T23:59:59.000Z

178

Neutron-Antineutron Oscillations in Nuclei Revisited  

E-Print Network (OSTI)

An upper limit on $n-\\bar n$ oscillations can be obtained from the stability of matter. This relation has been worked out theoretically and together with data yields $\\tau_{n\\bar n} > (1 - 2)\\times 10^8 sec$. A recent publication claims a different relation and finds a nuclear suppression of the $n\\to\\bar n$ oscillations which is two orders of magnitude weaker than the previous evaluations. Using the same approach we find, nevertheless, that the earlier estimates are correct and conclude that future experiments with free neutrons from reactors are capable to put a stronger limit on the $n - \\bar n$ oscillation time than experiments with large amount of neutrons bound in nuclei.

Joerg Huefner; Boris Kopeliovich

1998-07-01T23:59:59.000Z

179

ARM - Data Announcements Article  

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

Surface Cloud Condensation Nuclei Average Evaluation Product Available Surface Cloud Condensation Nuclei Average Evaluation Product Available Bookmark and Share This plot shows the concentration of CCN measured by the cloud condensation particle counter versus the concentration measured by the condensation particle counter. This plot shows the concentration of CCN measured by the cloud condensation particle counter versus the concentration measured by the condensation particle counter. Aerosol observing systems (AOS) at ARM's sites measure cloud condensation nuclei (CCN) at several supersaturations using a single-column CCN counter. The Average of Cloud Condensation Nuclei from AOS (AOSCCNAVG) value-added product (VAP) was developed to consolidate the relevant CCN parameters into a single file and average data over the 5-minute integration time of each

180

PARTICLE ACCELERATOR  

DOE Patents (OSTI)

ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

Teng, L.C.

1960-01-19T23:59:59.000Z

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


181

Design and operation of a counter-rotating aspirated compressor blowdown test facility  

E-Print Network (OSTI)

A unique counter-rotating aspirated compressor was tested in a blowdown facility at the Gas Turbine Laboratory at MIT. The facility expanded on experience from previous blowdown turbine and blowdown compressor experiments. ...

Parker, David V. (David Vickery)

2005-01-01T23:59:59.000Z

182

Optimal design and observation of counter-current autothermal reactors for the production of hydrogen  

Science Conference Proceedings (OSTI)

Autothermal reactors, coupling endothermic and exothermic reactions in parallel channels, represent one of the most promising technologies for hydrogen production. Building our prior results, the present work focuses on hydrogen generation in counter-current ...

Michael Baldea; Monica Zanfir; Prodromos Daoutidis

2009-06-01T23:59:59.000Z

183

Testing a Cloud Condensation Nuclei Remote Sensing Method  

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

a Cloud Condensation Nuclei a Cloud Condensation Nuclei Remote Sensing Method S. J. Ghan Climate Physics Pacific Northwest National Laboratory Richland, Washington D. R. Collin Department of Atmospheric Sciences Texas A&M University College Station, Texas Introduction Under certain conditions vertical profiles of cloud condensation nuclei (CCN) spectra can be retrieved from ground-based measurements (Ghan and Collins 2003). Surface measurements of the CCN spectrum are scaled by the ratio of the 180 backscatter (or extinction) profile to the surface backscatter (or extinction). The backscatter (or extinction) profile is measured by Raman lidar (RL), and is corrected to dry conditions using the vertical profile of relative humidity (calculated from the absolute

184

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

185

Active galactic nuclei and massive galaxy cores  

E-Print Network (OSTI)

(Context) Central active galactic nuclei (AGN) are supposed to play a key role in the evolution of their host galaxies. In particular, the dynamical and physical properties of the gas core must be affected by the injected energy. (Aims) Our aim is to study the effects of an AGN on the dark matter profile and on the central stellar light distribution in massive early type galaxies. (Methods) By performing self-consistent N-body simulations, we assume in our analysis that periodic bipolar outbursts from a central AGN can induce harmonic oscillatory motions on both sides of the gas core. (Results) Using realistic AGN properties, we find that the motions of the gas core, driven by such feedback processes, can flatten the dark matter and/or stellar profiles after 4-5 Gyr. These results are consistent with recent observational studies that suggest that most giant elliptical galaxies have cores or are "missing light" in their inner part. Since stars behave as a "collisionless" fluid similar to dark matter, the density profile both of stars and dark matter should be affected in a similar way, leading to an effective reduction in the central brightness.

Sebastien Peirani; Scott Kay; Joe Silk

2006-12-16T23:59:59.000Z

186

Fission Properties for R-Process Nuclei  

Science Conference Proceedings (OSTI)

We present a systematics of fission barriers and fission lifetimes for the whole landscape of superheavy elements (SHE), i.e., nuclei with Z 100. The fission lifetimes are also compared with the -decay half-lives. The survey is based on a self-consistent description in terms of the Skyrme-Hartree-Fock (SHF) approach. Results for various different SHF parametrizations are compared to explore the robustness of the predictions. The fission path is computed by quadrupole constrained SHF. The computation of fission lifetimes takes care of the crucial ingredients of the large-amplitude collective dynamics along the fission path, as self-consistent collective mass and proper quantum corrections. We discuss the different topologies of fission landscapes which occur in the realm of SHE (symmetric versus asymmetric fission, regions of triaxial fission, bimodal fission, and the impact of asymmetric ground states). The explored region is extended deep into the regime of very neutron-rich isotopes as they are expected to be produced in the astrophysical r process.

Erler, J. [Inst. fur Theoretische Physik II, Univ. Erlangen-Numberg, Germany/UTK/ORNL; Langanke, K. [GSI-Darmstadt/Tech. Univ. Darmstadt, Inst. Phys./Frankfurt Inst. Advanced Studies, Germany; Loens, H. P. [GSI-Darmstadt/Tech. Univ. Darmstadt, Inst. Phys.; Martinez-Pinedo, G. [GSI-Darmstadt/Tech. Univ. Darmstadt, Inst. Phys.; Reinhard, P.-G. [Inst. fur Theoretische Physik II, Univ. Erlangen-Numberg, Germany

2012-01-01T23:59:59.000Z

187

Fission properties for r-process nuclei  

E-Print Network (OSTI)

We present a systematics of fission barriers and fission lifetimes for the whole landscape of super-heavy elements (SHE), i.e. nuclei with Z>100. The fission lifetimes are also compared with the alpha-decay half-lives. The survey is based on a self-consistent description in terms of the Skyrme-Hartree-Fock (SHF) approach. Results for various different SHF parameterizations are compared to explore the robustness of the predictions. The fission path is computed by quadrupole constrained SHF. The computation of fission lifetimes takes care of the crucial ingredients of the large-amplitude collective dynamics along the fission path, as self-consistent collective mass and proper quantum corrections. We discuss the different topologies of fission landscapes which occur in the realm of SHE (symmetric versus asymmetric fission, regions of triaxial fission, bi-modal fission, and the impact of asymmetric ground states). The explored region is extended deep into the regime of very neutron-rich isotopes as they are expected to be produced in the astrophysical r process.

J. Erler; K. Langanke; H. P. Loens; G. Martínez-Pinedo; P. -G. Reinhard

2011-12-05T23:59:59.000Z

188

Particle swarm optimization with opposite particles  

Science Conference Proceedings (OSTI)

The particle swarm optimization algorithm is a kind of intelligent optimization algorithm. This algorithm is prone to be fettered by the local optimization solution when the particle's velocity is small. This paper presents a novel particle swarm ...

Rujing Wang; Xiaoming Zhang

2005-11-01T23:59:59.000Z

189

Anomaly of the moment of inertia of shape transitional nuclei  

Science Conference Proceedings (OSTI)

The change in the structure of the collective levels with spin angular momentum in atomic nuclei is often expressed in terms of the classical concepts of the kinematic and the dynamic moments of inertia varying with spin. For the well deformed even-even nuclei the kinematic moment of inertia increases with spin up to 10%-20%, at say I{sup {pi}} = 12{sup +}. However, for the shape transitional nuclei, or almost spherical nuclei, it increases with spin much faster. The pitfalls of using the rotor model form of kinematic moment of inertia in such cases are pointed out here. Alternative methods of extracting the nuclear structure information are explored. The important role of the ground state deformation is illustrated. The use of the power index formula for evaluating the effective moment of inertia, free from the assumption of the rotor model, is described.

Gupta, J. B. [Ramjas College, University of Delhi, Delhi-110 007 (India); Hamilton, J. H. [Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States)

2011-06-15T23:59:59.000Z

190

Properties of heavy and superheavy nuclei in supernova environments  

SciTech Connect

The properties of nuclei embedded in an electron gas are studied within the relativistic mean-field approach. These studies are relevant for nuclear properties in astrophysical environments such as neutron-star crusts and supernova explosions. The electron gas is treated as a constant background in the Wigner-Seitz cell approximation. We investigate the stability of nuclei with respect to {alpha} and {beta} decay. We find that the presence of the electrons leads to stabilizing effects for {alpha} decay at high electron densities. Furthermore, the screening effect shifts the proton dripline to more proton-rich nuclei, and the stability line with respect to {beta}-decay is shifted to more neutron-rich nuclei. Implications for the creation and survival of very heavy nuclear systems are discussed.

Buervenich, T. J.; Mishustin, I. N.; Greiner, W. [Frankfurt Institute for Advanced Studies Johann Wolfgang Goethe University, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany)

2008-05-12T23:59:59.000Z

191

Influence of Cloud Condensation Nuclei on Orographic Snowfall  

Science Conference Proceedings (OSTI)

Pollution aerosols acting as cloud condensation nuclei (CCN) have the potential to alter warm rain clouds via the aerosol first and second indirect effects in which they modify the cloud droplet population, cloud lifetime and size, rainfall ...

Stephen M. Saleeby; William R. Cotton; Douglas Lowenthal; Randolph D. Borys; Melanie A. Wetzel

2009-05-01T23:59:59.000Z

192

The Particle Adventure | Glossary  

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

Stable Does not decay. A particle is stable if there exist no processes in which a particle disappears and in its place different particles appear...

193

The Particle Adventure | Glossary  

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

Event What occurs when two particles collide or a single particle decays. Particle theories predict the probabilities of various possible events occurring when many similar...

194

The Particle Adventure | Glossary  

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

Charge A quantum number carried by a particle. Determines whether the particle can participate in an interaction process. A particle with electric charge has electrical...

195

Electric Dipole Moments of Neutron-Odd Nuclei  

E-Print Network (OSTI)

The electric dipole moments (EDMs) of neutron-odd nuclei with even protons are systematically evaluated. We first derive the relation between the EDM and the magnetic moment operators by making use of the core polarization scheme. This relation enables us to calculate the EDM of neutron-odd nuclei without any free parameters. From this calculation, one may find the best atomic system suitable for future EDM experiments.

Takehisa Fujita; Sachiko Oshima

2011-02-15T23:59:59.000Z

196

Turbulent particle deposition in a rectangular chamber: Study of the effect of particle size and ventilation regimes  

SciTech Connect

The interaction of aerosol particles with wall surfaces is important in modeling their behavior. This interaction is usually represented in theoretical models as a loss term. The loss rate is the rate at which particles deposit or react with the surfaces. This loss term is important in many branches of aerosol science including human health and indoor air quality. Increased surface deposition usually means lower concentrations of airborne particles and hence, lower exposure to the inhabitants. If the efficiency of the particle deposition is influenced by factors other than the particle size, such as a natural convection of the air, this has to be taken into account to evaluate the results. In this research, test aerosol sized from 15 nm to 3 {micro}m are produced by several different aerosol generators; the gas burner, the Collison nebulizer, the condensation aerosol generator, the orifice atomizer and the Vibrating Orifice Aerosol Generator (VOAG). A rectangular chamber whose dimensions are 75 x 75 x 180 cm{sup 3} was used in this study. The particles were injected into the chamber, with a known ventilation and the concentration decay was monitored by the Ultrafine Condensation Particle Counter (UCPC) and Optical Particle Counter (OPC). During the measurement, the air inside the chamber is moved by natural convection and ventilation effect. The results shows that the particle loss rate under the higher air exchange rate is larger and this is not only due to air exchange itself but also the wall deposition. The theoretical model presented by Benes and Holub (1996) agree with the experimental data better than the Crump and Seinfield (1981) model with the hypothesis of Plandtl`s mixing length. 118 refs.

Nomura, Yoshio

1996-04-01T23:59:59.000Z

197

EMC effect for light nuclei: new results from Jefferson Lab  

Science Conference Proceedings (OSTI)

High energy lepton scattering has been the primary tool for mapping out the quark distributions of nucleons and nuclei. Measurements of deep inelastic scattering in nuclei show that the quark distributions in heavy nuclei are not simply the sum of the quark distributions of the constituent proton and neutron, as one might expect for a weakly bound system. This modification of the quark distributions in nuclei is known as the EMC effect. I will discuss the results from Jefferson Lab (JLab) experiment E03-103, a precise measurement of the EMC effect in few-body nuclei with emphasis on the large x region. Data from the light nuclei suggests that the nuclear dependence of the high x quark distribution may depend on the nucleon's local environment, rather than being a purely bulk effect. In addition, I will also discuss about a future experiment at the upgraded 12 GeV Jefferson Lab facility which will further investigate the role of the local nuclear environment and the influence of detailed nuclear structure to the modification of quark distributions.

Daniel, A. [Dept. of Physics and Astronomy, Ohio University, Athens OH 45701 (United States)

2011-10-24T23:59:59.000Z

198

the Fractional Flotation of Flotation Column Particles Opportunity  

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

Enhancing Selectivity and Recovery in Enhancing Selectivity and Recovery in the Fractional Flotation of Flotation Column Particles Opportunity Although research is currently inactive on the patented technology "Method for Enhancing Selectivity and Recovery in the Fractional Flotation of Flotation Column Particles," the technology is available for licensing from the U.S. Department of Energy's National Energy Technology Laboratory (NETL). Disclosed in this patent is a method of particle separation from a feed stream comprised of particles of varying hydrophobicity by injecting the feed stream directly into the froth zone of a vertical flotation column in the presence of a counter-current reflux stream. The current invention allows the height of the feed stream injection and the reflux ratio to be

199

Design and development of a 3He replacement safeguards neutron counter based on 10B-lined proportional detector technology  

SciTech Connect

This presentation represents an overview of the experimental evaluation of a boron-lined proportional technology performed within an NA-241 sponsored project on testing of boron-lined proportional counters for the purpose of replacement of {sup 3}He technologies. The presented boron-lined technology will be utilized in a design of a full scale safeguards neutron coincidence counter. The design considerations and the Monte Carlo performance predictions for the counter are also presented.

Henzlova, Daniela [Los Alamos National Laboratory; Evans, Louise [Los Alamos National Laboratory; Menlove, Howard O. [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory; Rael, Carlos D. [Los Alamos National Laboratory; Martinez, Isaac P. [Los Alamos National Laboratory; Marlow, Johnna B. [Los Alamos National Laboratory

2012-07-16T23:59:59.000Z

200

A TRANSISTORIZED ALPHA COUNTER FOR AN ALPHA GAUGE  

SciTech Connect

A transistorized instrument prototype was designed and constructed to replace a vacuum-tube instrument in an alpha gauge, which measures the thickness density of gases. The instrument amplifies, shapes, discriminates, and counts alpha pulses from a Au-Si surface-barrier detector exposed to an alpha source in a gas-filled chamber. The circuit consists of a charge-sensitive preamplifier, a main amplifier with pulse clipping, a Schmitt trigger, a diode pump, and a count rate meter. Preliminary tests gave results comparable to the vacuum-tube instrument. Accuracy of counting was within 10% for 0.5- to 10-Mev alpha particles emitted at a maximum rate of 10/sup 6 per sec. The instrument was stable at 25 to 55 deg C, is small and portable, and costs less than 0. An infinitely thick, alpha source that will give a high count rate is being constructed for final tests. (auth)

Kopp, M.C.

1962-08-23T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

Calibration of a Photometric Cloud Condensation Nucleus Counter Designed for Deployment on a Balloon Package  

Science Conference Proceedings (OSTI)

The importance of atmospheric aerosols in understanding global climate changes has renewed interest in measurements of cloud condensation nuclei (CCN). To obtain high-resolution (125 m) vertical profiles of CCN number concentration, a balloon-...

D. J. Delene; T. Deshler

2000-04-01T23:59:59.000Z

202

Mechanism of supporting sub-communicator collectives with O(64) counters as opposed to one counter for each sub-communicator  

DOE Patents (OSTI)

A system and method for enhancing barrier collective synchronization on a computer system comprises a computer system including a data storage device. The computer system includes a program stored in the data storage device and steps of the program being executed by a processor. The system includes providing a plurality of communicators for storing state information for a bather algorithm. Each communicator designates a master core in a multi-processor environment of the computer system. The system allocates or designates one counter for each of a plurality of threads. The system configures a table with a number of entries equal to the maximum number of threads. The system sets a table entry with an ID associated with a communicator when a process thread initiates a collective. The system determines an allocated or designated counter by searching entries in the table.

Kumar, Sameer; Mamidala, Amith R.; Ratterman, Joseph D.; Blocksome, Michael; Miller, Douglas

2013-09-03T23:59:59.000Z

203

U.S., China Partner to Counter Nuclear Smuggling | Department of Energy  

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

Partner to Counter Nuclear Smuggling Partner to Counter Nuclear Smuggling U.S., China Partner to Counter Nuclear Smuggling January 19, 2011 - 12:00am Addthis WASHINGTON D.C. - The Department of Energy's National Nuclear Security Administration (NNSA) today announced the signing of a memorandum of understanding (MOU) with China that paves the way for the establishment of a radiation detection training center in Qinhuangdao, China. Deputy Secretary of Energy Daniel Poneman and Vice Minister SUN Yibiao of the General Administration of China Customs signed the MOU in a ceremony at DOE headquarters in Washington. The signed comes as part of Chinese President Hu Jintao's state visit to Washington, DC. "This agreement represents the shared commitment of both the United States and China to enhance global peace and security by working to prevent

204

COO-3072-119 RESULTS ON THE PERFORMANCE OF A BROAD BAND FOCUSSING CHERENKOV COUNTER*  

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

3072-119 3072-119 ^ RESULTS ON THE PERFORMANCE OF A BROAD BAND FOCUSSING CHERENKOV COUNTER* Sherman,"'"'' R. C. W e b b , ' ' ' " ' ' " ' " M. ^.otov-~ S C i i v ^ ^ - - ^ - ^ Cester, V. L. Fitch, A. Montag, S. Sherman, R. C. Webb, M. S. Witherell Department of Physics, Princeton University, Princeton, N. J. 085A4 Abstract The field of ring imaging (broad band differential) Cherenkov detectors-^ has become a very active area of interest in detector development at several high energy physics laboratories. Our group has previously report- ed2 on a method of Cherenkov ring imaging for a counter with large momentum and angular acceptance using stan- dard photo multipliers. Recently, we have applied this technique to the design of a set of Cherenkov counters

205

Study of a Threshold Cherenkov Counter Based on Silica Aerogels with Low Refractive Indices ?  

E-Print Network (OSTI)

To identify ? ± and K ± in the region of 1.0 ? 2.5 GeV/c, a threshold Cherenkov counter equipped with silica aerogels has been investigated. Silica aerogels with a low refractive index of 1.013 have been successfully produced using a new technique. By making use of these aerogels as radiators, we have constructed a Cherenkov counter and have checked its properties in a test beam. The obtained results have demonstrated that our aerogel was transparent enough to make up for loss of the Cherenkov photon yield due to a low refractive index. Various configurations for the photon collection system and some types of photomultipliers, such as the fine-mesh type, for a read out were also tested. From these studies, our design of a Cherenkov counter dedicated to ?/K separation up to a few GeV/c with an efficiency greater than 90 % was considered. 1

I. Adachi; T. Sumiyoshi; K. Hayashi; N. Iida; R. Enomoto; K. Tsukada; R. Suda; S. Matsumoto; K. Natori; M. Yokoyama; H. Yokogawa

1994-01-01T23:59:59.000Z

206

D Note 3563 LED Pulser System for the D Muon Upgrade Scintillation Counters  

E-Print Network (OSTI)

We present the technical design for an LED based pulser system for the D Upgrade Muon Scintillation counters. For Run II, accurate timing information from the scintillation counters is imperative for the proper performance of the muon triggers. The LED Pulser System will serve in the commissioning of the counters and for the continuous monitoring of the PMTs ' performances and gains. A detailed description of the system is presented, as well as the results of tests on individual components and integrated system. Proceedures for production, assembly, quality control, installation, and commissioning are presented. Cost estimates and resource needs to complete the system are presented, as well as an estimated schedule. From the test results, the D LED Pulser System performs at a level exceeding speci cations for a fraction of the initial cost estimated for performing the required tasks.

Pierrick Hanlet Matthew Marcus; Al Ito; Bob Jones; Tom Regan; B. S. Acharya; Juan Pablo Negret; Manuel Zanabria

1999-01-01T23:59:59.000Z

207

Method for enhancing selectivity and recovery in the fractional flotation of particles in a flotation column  

DOE Patents (OSTI)

The method relates to particle separation from a feed stream. The feed stream is injected directly into the froth zone of a vertical flotation column in the presence of a counter-current reflux stream. A froth breaker generates a reflux stream and a concentrate stream, and the reflux stream is injected into the froth zone to mix with the interstitial liquid between bubbles in the froth zone. Counter-current flow between the plurality of bubbles and the interstitial liquid facilitates the attachment of higher hydrophobicity particles to bubble surfaces as lower hydrophobicity particles detach. The height of the feed stream injection and the reflux ratio may be varied in order to optimize the concentrate or tailing stream recoveries desired based on existing operating conditions.

Klunder, Edgar B. (Bethel Park, PA)

2011-08-09T23:59:59.000Z

208

Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations  

Science Conference Proceedings (OSTI)

The coordinate space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables self-consistent treatment of mean field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate 2D lattice Skyrme-HFB solver HFB-AX based on B-splines. Compared to previous implementations, we made a number of improvements aimed at boosting the solver's performance. These include: explicit imposition of axiality and space inversion, use of the modified Broyden's method to solve self-consistent equations, and a partial parallelization of the code. HFB-AX has been benchmarked against other HFB solvers, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multi-resolution wavelet method. Illustrative calculations are carried out for stable and weakly bound nuclei at spherical and very deformed shapes, including constrained fission pathways. In addition to providing new physics insights, HFB-AX can serve as a useful tool to assess the reliability and applicability of coordinate-space and configuration-space HFB solvers, both existing and in development.

Pei, Junchen [ORNL; Stoitsov, M. V. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Fann, G. I. [Oak Ridge National Laboratory (ORNL); Nazarewicz, W. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Schunck, N. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Xu, F. R. [Peking University

2008-01-01T23:59:59.000Z

209

Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations  

E-Print Network (OSTI)

The coordinate space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables self-consistent treatment of mean-field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate 2D lattice Skyrme-HFB solver {\\hfbax} based on B-splines. Compared to previous implementations, we made a number of improvements aimed at boosting the solver's performance. These include: explicit imposition of axiality and space inversion, use of the modified Broyden's method to solve self-consistent equations, and a partial parallelization of the code. {\\hfbax} has been benchmarked against other HFB solvers, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multiresolution wavelet method. Illustrative calculations are carried out for stable and weakly bound nuclei at spherical and very deformed shapes, including constrained fission pathways. In addition to providing new physics insights, {\\hfbax} can serve as a useful tool to assess the reliability and applicability of coordinate-space and configuration-space HFB solvers, both existing and in development.

J. C. Pei; M. V. Stoitsov; G. I. Fann; W. Nazarewicz; N. Schunck; F. R. Xu

2008-07-18T23:59:59.000Z

210

Nuclear diagnostic for fast alpha particles  

DOE Patents (OSTI)

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Grisham, Larry R. (Lawrence Township, Mercer County, NJ); Post, Jr., Douglass E. (Belle Mead, NJ); Dawson, John M. (Pacific Palisades, CA)

1986-01-01T23:59:59.000Z

211

Leading twist nuclear shadowing phenomena in hard processes with nuclei  

SciTech Connect

We present and discuss the theory and phenomenology of the leading twist theory of nuclear shadowing which is based on the combination of the generalization of Gribov-Glauber theory, QCD factorization theorems, and HERA QCD analysis of diffraction in lepton-proton deep inelastic scattering (DIS). We apply this technique for the analysis of a wide range of hard processes with nuclei-inclusive DIS on deuterons, medium-range and heavy nuclei, coherent and incoherent diffractive DIS with nuclei, and hard diffraction in proton-nucleus scattering - and make predictions for the effect of nuclear shadowing in the corresponding sea quark and gluon parton distributions. We also analyze the role of the leading twist nuclear shadowing in generalized parton distributions in nuclei and certain characteristics of final states in nuclear DIS. We discuss the limits of applicability of the leading twist approximation for small x scattering off nuclei and the onset of the black disk regime and methods of detecting it. It will be possible to check many of our predictions in the near future in the studies of the ultraperipheral collisions at the Large Hadron Collider (LHC). Further checks will be possible in pA collisions at the LHC and forward hadron production at Relativistic Heavy Ion Collider (RHIC). Detailed tests will be possible at an Electon-Ion Collider (EIC) in USA and at the Large Hadron-Electron Collider (LHeC) at CERN.

Leonid Frankfurt, Vadim Guzey, Mark Strikman

2012-03-01T23:59:59.000Z

212

Topology of "white" stars in relativistic fragmentation of light nuclei  

E-Print Network (OSTI)

In the present paper, experimental observations of the multifragmentation processes of light relativistic nuclei carried out by means of emulsions are reviewed. Events of the type of "white" stars in which the dissociation of relativistic nuclei is not accompanied by the production of mesons and the target-nucleus fragments are considered. A distinctive feature of the charge topology in the dissociation of the Ne, Mg, Si, and S nuclei is an almost total suppression of the binary splitting of nuclei to fragments with charges higher than 2. The growth of the nuclear fragmentation degree is revealed in an increase in the multiplicity of singly and doubly charged fragments with decreasing charge of the non-excited part of the fragmenting nucleus. The processes of dissociation of stable Li, Be, B, C, N, and O isotopes to charged fragments were used to study special features of the formation of systems consisting of the lightest $\\alpha$, d, and t nuclei. Clustering in form of the $^3$He nucleus can be detected in "white" stars via the dissociation of neutron-deficient Be, B, C, and N isotopes.

N. P. Andreeva; V. Bradnova; S. Vokal; A. Vokalova; A. Sh. Gaitinov; S. G. Gerasimov; L. A. Goncharova; V. A. Dronov; P. I. Zarubin; I. G. Zarubina; G. I. Orlova; A. D. Kovalenko; A. Kravchakova; V. G. Larionova; F. G. Lepekhin; O. V. Levitskaya; A. I. Malakhov; A. A. Moiseenko; G. I. Orlova; N. G. Peresadko; N. G. Polukhina; P. A. Rukoyatkin; V. V. Rusakova; N. A. Salmanova; V. R. Sarkisyan; B. B. Simonov; E. Stan; R. Stanoeva; M. M. Chernyavsky; M. Haiduc; S. P. Kharlamov; I. Tsakov; T. V. Shchedrina

2006-05-15T23:59:59.000Z

213

A Comparison of Lidar and Balloon-Borne Particle Counter Measurements of the Stratospheric Aerosol 1974–1980  

Science Conference Proceedings (OSTI)

We compare a series of 85 dustsonde measurements and 84 lidar measurements made in midlatitude North America during 1974–80. This period includes two major volcanic increases (Fuego in 1974 and St. Helens in 1980), as well as an unusually clean, ...

T. J. Swissler; P. Hamill; M. Osborn; P. B. Russell; M. P. McCormick

1982-04-01T23:59:59.000Z

214

Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations  

E-Print Network (OSTI)

The coordinate space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables self-consistent treatment of mean-field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate 2D lattice Skyrme-HFB solver {\\hfbax} based on B-splines. Compared to previous implementations, we made a number of improvements aimed at boosting the solver's performance. These include: explicit imposition of axiality and space inversion, use of the modified Broyden's method to solve self-consistent equations, and a partial parallelization of the code. {\\hfbax} has been benchmarked against other HFB solvers, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multiresolution wavelet method. Illustrative calculations are carried out for stable and ...

Pei, J C; Fann, G I; Nazarewicz, W; Schunck, N; Xu, F R

2008-01-01T23:59:59.000Z

215

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

216

Extraction of Structure Functions from Quasielastic Electron Scattering (e,e') from Medium and Heavy Nuclei  

E-Print Network (OSTI)

Using a relativistic mean-field single particle knock-out model for (e,e') reactions on nuclei, we investigate approximate treatments of Coulomb distortion effects and the extraction of longitudinal and transverse structure functions. We show that an effective momentum approximation (EMA) when coupled with a focusing factor provides a good description of the transverse contributions to the (e,e') cross sections for electron energies above 300 MeV on 208Pb. This approximation is not as good for the longitudinal contributions even for incident electron eneriges above 1 GeV and if one requires very precise extraction of longitudinal and transverse structure functions in the quasielastic region it is necessary to utilize distortion factors based on a nuclear model and a more accurate inclusion of Coulomb distortion effects.

K. S. Kim; L. E. Wright

2005-05-12T23:59:59.000Z

217

ON THE MICROSCOPIC AND MACROSCOPIC ASPECTS OF NUCLEAR STRUCTURE WITH APPLICATIONS TO SUPERHEAVY NUCLEI  

SciTech Connect

The thesis is concerned with the relation between a microscopic approach and a macroscopic approach to the study of the nuclear binding energy as a function of neutron number, proton number and nuclear deformations. First of all we give a general discussion of the potential energy of a system which can be divided into a bulk region and a thin skin layer. We find that this energy can be written down in the usual liquid drop type of expression, i.e., in terms of the volume, the surface area and other macroscopic properties of the system. The discussion is illustrated by a study of noninteracting particles in an orthorhombic potential well with zero potential inside and infinite potential outside. The total energy is calculated both exactly (a microscopic approach) and also from a liquid drop type of expression (a macroscopic approach). It turns out that the latter approach reproduces the smooth average of the exact results very well. We next make a digression to study the saddle point shapes of a charged conducting drop on a pure liquid drop model. We compare the properties of a conducting drop with those of a drop whose charges are distributed uniformly throughout its volume. The latter is the usual model employed in the study of nuclear fission. We also determined some of the more important symmetric saddle point shapes. In the last part of the thesis we generalize a method due to Strutinski to synthesize a microscopic approach (the Nilsson model) and a macroscopic approach (the liquid drop model). The results are applied to realistic nuclei. The possible occurrence of shape isomers comes as a natural consequence of the present calculation. Their trends as a function of neutron and proton members are discussed and the results are tabulated. We also work out the stabilities of the predicted superheavy nuclei with proton number around 114 and neutron number around 184 and 196. Some of these nuclei appear to have extremely long life times. The possible experimental production of these superheavy nuclei are also discussed.

Tsang, Chin-Fu.

1969-05-22T23:59:59.000Z

218

Structure of unstable nuclei around N = 28 described by a shell model with the monopole-based universal interaction  

SciTech Connect

The structure of exotic nuclei around N = 28 is investigated in the sd-pf shell-model space using a new effective interaction. The cross-shell part of the interaction is provided by the monopole-based universal interaction which has been successful in accounting for single-particle evolution in several mass regions. Focusing on the nuclear structure that is sensitive to the shell evolution, we show successful results for the proton-hole states in K isotopes and large deformation in {sup 42}Si. The results demonstrate that the present scheme may be a promising way for constructing an effective interaction for other mass regions.

Utsuno, Yutaka [Advanced Science Research Center, Japan Atomic Energy Agency (Japan); Otsuka, Takaharu [Department of Physics, University of Tokyo (Japan); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing MI 48824 (United States); Brown, B. Alex [Department of Physics and Astronomy, Michigan State University, East Lansing MI 48824 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing MI 48824 (United States); Honma, Michio [Center for Mathematical Sciences, University of Aizu, Ikki-machi, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); Mizusaki, Takahiro [Institute for National Sciences, Senshu University, Tokyo, 101-8425 (Japan)

2011-05-06T23:59:59.000Z

219

Elementary particle physics---Experimental  

SciTech Connect

We are continuing a research program in high energy experimental particle physics and particle astrophysics. Studies of high energy hadronic interactions were performed using several techniques, in addition, a high energy leptoproduction experiment was continued at the Fermi National Accelerator Laboratory. We are participants in a joint US/Japan program to study nuclear interactions at energies two orders of magnitude greater than those of existing accelerators. The data are being collected with ballon-borne emulsion chambers. The properties of nuclear interactions at these high energies will reveal whether new production mechanisms come into play due to the high nuclear densities and temperatures obtained. We carried out closely related studies of hadronic interactions in emulsions exposed to high energy accelerator beams. We are members of a large international collaboration which has exposed emulsion chamber detectors to beams of {sup 32}S and {sup 16}O with energy 60 and 200 GeV/n at CERN and 15 GeV/n at Brookhaven National Laboratory. The primary objectives of this program are to determine the existence and properties of the hypothesized quark-gluon phase of matter, and its possible relation to a variety of anomalous observations. Studies of leptoproduction processes at high energies involve two separate experiments, one using the Tevatron 500 GeV muon beam and the other exploring the >TeV regime. We are participants in Fermilab experiment E665 employing a comprehensive counter/streamer chamber detector system. During the past year we joined the DUMAND Collaboration, and have been assigned responsibility for development and construction of critical components for the deep undersea neutrino detector facility, to be deployed in 1991. In addition, we are making significant contributions to the design of the triggering system to be used.

Lord, J.J.; Burnett, T.H.; Wilkes, R.J.

1990-09-20T23:59:59.000Z

220

Application of the active well coincidence counter to the measurement of uranium  

Science Conference Proceedings (OSTI)

An Active Well Coincidence Counter has been developed to assay uranium fuel material in field inspection applications. The unit is used to measure bulk UO/sub 2/ samples, high enrichment uranium metals, LWR fuel pellets, and /sup 233/U-Th fuel materials which have very high gamma-ray backgrounds.

Menlove, H.O.; Foley, J.E.; Bosler, G.E.

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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.


221

A study of hardware performance monitoring counter selection in power modeling of computing systems  

Science Conference Proceedings (OSTI)

Power management and energy savings in high-performance computing has become an increasingly important design constraint. The foundation of many power/energy saving methods is based on power consumption models, which commonly rely on hardware performance ... Keywords: energy saving,performance monitoring counters,power modeling

Reza Zamani; Ahmad Afsahi

2012-06-01T23:59:59.000Z

222

Using behavioral measures to assess counter-terrorism training in the field  

Science Conference Proceedings (OSTI)

Development of behavioral pattern recognition and analysis skills is an essential element of counter-terrorism training, particularly in the field. Three classes of behavioral measures were collected in an assessment of skill acquisition during a US ... Keywords: behavioral observations, knowledge-skills-attitudes, profiling, scenarios, situational judgment tests, tracking

V. Alan Spiker; Joan H. Johnston

2011-07-01T23:59:59.000Z

223

Position-sensitive proportional counter with low-resistance metal-wire anode  

DOE Patents (OSTI)

A position-sensitive proportional counter circuit is provided which allows the use of a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counter. A pair of specially designed active-capacitance preamplifiers are used to terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, low-noise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at the anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates (>10.sup.6 counts/sec).

Kopp, Manfred K. (Oak Ridge, TN)

1980-01-01T23:59:59.000Z

224

Tag-only aging-counter localization for the R-LIM2 system  

Science Conference Proceedings (OSTI)

With the large number of items stored in present-day libraries, locating the exact position of an item is time-consuming. This is true not only for poorly managed libraries, but also for well maintained libraries. In the former case, the problem is rather ... Keywords: Aging counter, Book retrieval, Library, Localization, R-LIM2, RFID

Jung-Wook Choi; Dong-Ik Oh

2011-03-01T23:59:59.000Z

225

A Vindication of the Twomey-Type Cloud Condensation Nucleus Counter  

Science Conference Proceedings (OSTI)

The performance of the Twomey-type cloud condensation nucleus (CCN) counter is evaluated by a numerical simulation and found to be better than that predicted in an earlier study. Due to a lack of data on CCN spectra at low supersaturations, the ...

D. J. Alofs; Yue-Tung Tue

1986-09-01T23:59:59.000Z

226

A humidity temperature test on the HLNC (high-level neutron coincidence counter) instrument  

SciTech Connect

This paper presents the findings of a laboratory study made to determine the effects of unusual climatic conditions on high-level neutron coincidence counters (HLNCs). The capability of the instrument, when undesirable temperatures and/or humidities are present, the change in count rate as temperature and humidity increase, and the extent of humidity/temperature interaction are examined.

Goldman, A.; Augustson, R.; Karlin, E.W.

1987-07-01T23:59:59.000Z

227

SCALING OF COUNTER-CURRENT IMBIBITION PROCESSES IN LOW-PERMEABILITY  

E-Print Network (OSTI)

. Schematic of imbibition cell set up for counter current imbibition. 20 2. Porosity images of diatomite cores, initial heating of a cold reservoir is accompanied by condensation and flow of the resulting hot water tomography (CT) imbibition cell to quantify co-current imbibition rates and saturation profiles as well

228

Calibration of Knollenberg FSSP Light-Scattering Counters for Measurement of Cloud Droplets  

Science Conference Proceedings (OSTI)

Measurement of cloud drop size distributions with the Knollenberg model FSSP-100 light-scattering counter can lead to artificial bumps or knees in the distributions at 0.6 ?m and sometimes 2–4 ?m radius if the manufacturer-supplied calibration ...

R. G. Pinnick; D. M. Garvey; L. D. Duncan

1981-09-01T23:59:59.000Z

229

Description of Exotic Nuclei with the Interacting Boson Model  

Science Conference Proceedings (OSTI)

Even--even nuclei in the A{approx}100 mass region are investigated within the framework of the interacting boson model-1 (IBM-1). The study includes energy spectra and electric quadrupole transition properties of zirconium, molybdenum, ruthenium and palladium isotopes with neutron number N{>=}54. A global parametrization of the IBM-1 hamiltonian is found leading to a description of 301 collective levels in 30 nuclei with a root-mean-square deviation from the observed level energies of 119 keV. The geometric character of the nuclei can be visualized by plotting the potential energy surface V({beta},{gamma}) obtained from the IBM-1 hamiltonian in the classical limit. The parametrization established on the basis of known elements is then used to predict properties of the unknown, neutron-rich isotopes {sup 106}Zr, {sup 112}Mo, {sup 116}Ru and {sup 120}Pd.

Boeyuekata, M. [Grand Accelerateur National d'Ions Lourds, B.P. 55027, F-14076 Caen Cedex 5 (France); Physics Department, Faculty of Science and Arts, University of Kirikkale, 71100 Kirikkale (Turkey); Van Isacker, P. [Grand Accelerateur National d'Ions Lourds, B.P. 55027, F-14076 Caen Cedex 5 (France); Uluer, I. [Physics Department, Faculty of Science and Arts, University of Kirikkale, 71100 Kirikkale (Turkey)

2008-11-11T23:59:59.000Z

230

Testing a Cloud Condensation Nuclei Remote Sensing Method  

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

a Cloud Condensation Nuclei a Cloud Condensation Nuclei Remote Sensing Method S. J. Ghan Climate Dynamics Group Pacific Northwest National Laboratory Richland, Washington Introduction Under certain conditions vertical profiles of cloud condensation nuclei (CCN) spectra can be retrieved from ground-based measurements. Surface measurements of the CCN spectrum are scaled by the ratio of the backscatter (or extinction) profile to the surface backscatter (or extinction). The backscatter (or extinction) profile is measured by Raman lidar, and is corrected to dry conditions using the vertical profile of relative humidity (also measured by Raman Lidar) and surface measurements of the dependence of backscatter (or extinction) on relative humidity. This method should be accurate up to

231

Formation of superheavy nuclei in cold fusion reactions  

E-Print Network (OSTI)

Within the concept of the dinuclear system (DNS), a dynamical model is proposed for describing the formation of superheavy nuclei in complete fusion reactions by incorporating the coupling of the relative motion to the nucleon transfer process. The capture of two heavy colliding nuclei, the formation of the compound nucleus and the de-excitation process are calculated by using an empirical coupled channel model, solving a master equation numerically and applying statistical theory, respectively. Evaporation residue excitation functions in cold fusion reactions are investigated systematically and compared with available experimental data. Maximal production cross sections of superheavy nuclei in cold fusion reactions with stable neutron-rich projectiles are obtained. Isotopic trends in the production of the superheavy elements Z=110, 112, 114, 116, 118 and 120 are analyzed systematically. Optimal combinations and the corresponding excitation energies are proposed.

Feng, Zhao-Qing; Li, Jun-Qing; Scheid, Werner

2007-01-01T23:59:59.000Z

232

Formation of superheavy nuclei in cold fusion reactions  

E-Print Network (OSTI)

Within the concept of the dinuclear system (DNS), a dynamical model is proposed for describing the formation of superheavy nuclei in complete fusion reactions by incorporating the coupling of the relative motion to the nucleon transfer process. The capture of two heavy colliding nuclei, the formation of the compound nucleus and the de-excitation process are calculated by using an empirical coupled channel model, solving a master equation numerically and applying statistical theory, respectively. Evaporation residue excitation functions in cold fusion reactions are investigated systematically and compared with available experimental data. Maximal production cross sections of superheavy nuclei in cold fusion reactions with stable neutron-rich projectiles are obtained. Isotopic trends in the production of the superheavy elements Z=110, 112, 114, 116, 118 and 120 are analyzed systematically. Optimal combinations and the corresponding excitation energies are proposed.

Zhao-Qing Feng; Gen-Ming Jin; Jun-Qing Li; Werner Scheid

2007-07-17T23:59:59.000Z

233

Structure of even-even nuclei using a mapped collective Hamiltonian and the D1S Gogny interaction  

E-Print Network (OSTI)

A systematic study of low energy nuclear structure at normal deformation is carried out using the Hartree-Fock-Bogoliubov theory extended by the Generator Coordinate Method and mapped onto a 5-dimensional collective quadrupole Hamiltonian. Results obtained with the Gogny D1S interaction are presented from dripline to dripline for even-even nuclei with proton numbers Z=10 to Z=110 and neutron numbers N less than 200. The properties calculated for the ground states are their charge radii, 2-particle separation energies, correlation energies, and the intrinsic quadrupole shape parameters. For the excited spectroscopy, the observables calculated are the excitation energies and quadrupole as well as monopole transition matrix elements. We examine in this work the yrast levels up to J=6, the lowest excited 0^+ states, and the two next yrare 2^+ states. The theory is applicable to more than 90% of the nuclei which have tabulated measurements. The data set of the calculated properties of 1712 even-even nuclei, including spectroscopic properties for 1693 of them, are provided in CEA website and EPAPS repository with this article \\cite{epaps}.

J. P. Delaroche; M. Girod; J. Libert; H. Goutte; S. Hilaire; S. Peru; N. Pillet; G. F. Bertsch

2009-10-15T23:59:59.000Z

234

Nuclear Superfluidity in Exotic Nuclei and Neutron Stars  

E-Print Network (OSTI)

Nuclear superfludity in exotic nuclei close to the drip lines and in the inner crust matter of neutron stars have common features which can be treated with the same theoretical tools. In the first part of my lecture I discuss how two such tools, namely the HFB approach and the linear response theory can be used to describe the pairing correlations in weakly bound nuclei, in which the unbound part of the energy spectrum becomes important. Then, using the same models, I shall discuss how the nuclear superfluidity can affect the thermal properties of the inner crust of neutron stars.

Nicolae Sandulescu

2006-12-11T23:59:59.000Z

235

A BPS Skyrme model and phenomenology of nuclei  

Science Conference Proceedings (OSTI)

We define a BPS Skyrme model, which is integrable, solvable and with solitons saturating a topological bound. When applied to nuclear physics, the model cures several serious problems appearing in the standard Skyrme model as well as in its typical generalizations. At the classical level, it qualitatively reproduces the main features of the liquid drop model of nuclei, providing proper relations between masses and radii of nuclei and the baryon number. In spite of its rather unusual form, the model also allows for the semiclassical quantization.

Adam, Christoph; Sanchez-Guillen, Joaquin [Departamento de Fisica de Particulas, Universidad de Santiago, E-15782 Santiago de Compostela, Spain and Instituto Galego de Fisica de Altas Enerxias (IGFAE), E-15782 Santiago de Compostela (Spain); Wereszczynski, Andrzej [Physics Institute, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland)

2011-05-23T23:59:59.000Z

236

ENHANCED ACCRETION RATES OF STARS ON SUPERMASSIVE BLACK HOLES BY STAR-DISK INTERACTIONS IN GALACTIC NUCLEI  

Science Conference Proceedings (OSTI)

We investigate the dynamical interaction of a central star cluster surrounding a supermassive black hole (SMBH) and a central accretion disk (AD). The dissipative force acting on stars in the disk leads to an enhanced mass flow toward the SMBH and to an asymmetry in the phase space distribution due to the rotating AD. The AD is considered as a stationary Keplerian rotating disk, which is vertically extended in order to employ a fully self-consistent treatment of stellar dynamics including the dissipative force originating from star-gas ram pressure effects. The stellar system is treated with a direct high-accuracy N-body integration code. A star-by-star representation, desirable in N-body simulations, cannot be extended to real particle numbers yet. Hence, we carefully discuss the scaling behavior of our model with regard to particle number and tidal accretion radius. The main idea is to find a family of models for which the ratio of two-body relaxation time and dissipation time (for kinetic energy of stellar orbits) is constant, which then allows us to extrapolate our results to real parameters of galactic nuclei. Our model is derived from basic physical principles and as such it provides insight into the role of physical processes in galactic nuclei, but it should be regarded as a first step toward more realistic and more comprehensive simulations. Nevertheless, the following conclusions appear to be robust: the star accretion rate onto the AD and subsequently onto the SMBH is enhanced by a significant factor compared to purely stellar dynamical systems neglecting the disk. This process leads to enhanced fueling of central disks in active galactic nuclei (AGNs) and to an enhanced rate of tidal stellar disruptions. Such disruptions may produce electromagnetic counterparts in the form of observable X-ray flares. Our models improve predictions for their rates in quiescent galactic nuclei. We do not yet model direct stellar collisions in the gravitational potential well of the black hole, which could further enhance the growth rate of the black hole. Our models are relevant for quiescent galactic nuclei, because all our mass accretion rates would give rise to luminosities much smaller than the Eddington luminosity. To reach Eddington luminosities, outflows, and feedback as in the most active QSOs, other scenarios are needed, such as gas accretion after galaxy mergers. However, for AGNs close to the Eddington limit, this process may not serve as the dominant accretion process due to the long timescale.

Just, Andreas; Yurin, Denis; Makukov, Maxim; Berczik, Peter; Omarov, Chingis; Spurzem, Rainer [Astronomisches Rechen-Institut, Zentrum fuer Astronomie, Universitaet Heidelberg, Moenchhof-Strasse 12-14, D-69120 Heidelberg (Germany); Vilkoviskij, Emmanuil Y., E-mail: just@ari.uni-heidelberg.de [Fesenkov Astrophysical Institute, Observatory 23, 050020 Almaty (Kazakhstan)

2012-10-10T23:59:59.000Z

237

Gravitational Model of High Energy Particles in a Collimated Jet  

E-Print Network (OSTI)

Observations suggest that relativistic particles play a fundamental role in the dynamics of jets emerging from active galactic nuclei as well as in their interaction with the intracluster medium. However, no general consensus exists concerning the acceleration mechanism of those high energy particles. A gravitational acceleration mechanism is here proposed, in which particles leaving precise regions within the ergosphere of a rotating supermassive black hole produce a highly collimated flow. These particles follow unbound geodesics which are asymptotically parallel to the spin axis of the black hole and are characterized by the energy $E$, the Carter constant ${\\cal Q}$ and zero angular momentum of the component $L_z$. If environmental effects are neglected, the present model predicts at distances of about 140 kpc from the ergosphere the presence of electrons with energies around 9.4 GeV. The present mechanism can also accelerate protons up to the highest energies observed in cosmic rays by the present experiments.

J. A. de Freitas Pacheco; J. Gariel; G. Marcilhacy; N. O. Santos

2012-10-02T23:59:59.000Z

238

Reaction mechanisms for weakly-bound, stable nuclei and unstable, halo nuclei on medium-mass targets  

E-Print Network (OSTI)

An experimental overview of reactions induced by the stable, but weakly-bound nuclei 6Li, 7Li and 9Be, and by the exotic, halo nuclei 6He, 8B, 11Be and 17F on medium-mass targets, such as 58Ni, 59Co or 64Zn, is presented. Existing data on elastic scattering, total reaction cross sections, fusion processes, breakup and transfer channels are discussed in the framework of a CDCC approach taking into account the breakup degree of freedom.

Beck, C; Papka, P; Courtin, S; Souza, F A; Carlin, N; Neto, R Liguori; De Moura, M M; del Santo, M G; Suaide, A A I; Munhoz, M G; Szanto, E M; de Toledo, A Szanto; Keeley, N; Díaz-Torres, A; Hagino, K

2009-01-01T23:59:59.000Z

239

The Particle Adventure | Glossary  

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

Boson A particle that has integer intrinsic angular momentum (spin) measured in units of h-bar (spin 0, 1, 2, ...). All particles are either fermions or bosons. The particles...

240

The Particle Adventure | Glossary  

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

Rest Mass The rest mass (m) of a particle is the mass defined by the energy of the isolated (free) particle at rest, divided by the speed of light squared. When particle physicists...

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


241

The Particle Adventure | Glossary  

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

Decay A process in which a particle disappears and in its place different particles appear. The sum of the masses of the produced particles is always less than the mass of the...

242

The Particle Adventure  

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

Is this particle really the Higgs... Is this particle really the Higgs Boson? Does it swim and quack like a duck? While decays of this kind had been observed for the new particle...

243

Ground State Magnetic Moments of Mirror Nuclei Studied at NSCL  

E-Print Network (OSTI)

Progress in the measurement of the ground state magnetic moments of mirror nuclei at NSCL is presented. The systematic trend of the spin expectation value $$ and the linear behavior of $\\gamma_p$ versus $\\gamma_n$, both extracted from the magnetic moments of mirror partners, are updated to include all available data.

P. F. Mantica; K. Minamisono

2009-01-22T23:59:59.000Z

244

Pairing: from atomic nuclei to neutron-star crusts  

E-Print Network (OSTI)

Nuclear pairing is studied both in atomic nuclei and in neutron-star crusts in the unified framework of the energy-density functional theory using generalized Skyrme functionals complemented with a local pairing functional obtained from many-body calculations in homogeneous nuclear matter using realistic forces.

Chamel, N; Goriely, S

2013-01-01T23:59:59.000Z

245

Band structure of doubly-odd nuclei around mass 130  

Science Conference Proceedings (OSTI)

Nuclear structure of the doublet bands in the doubly-odd nuclei with mass A{approx}130 is studied in terms of a pair-truncated shell model. The model reproduces quite well the energy levels of the doublet bands and the electromagnetic transitions. The analysis of the electromagnetic transitions reveals new band structure of the doublet bands.

Higashiyama, Koji [Department of Physics, Chiba Institute of Technology, Narashino, Chiba 275-0023 (Japan); Yoshinaga, Naotaka [Department of Physics, Saitama University, Saitama City 338-8570 (Japan)

2011-05-06T23:59:59.000Z

246

An Indirect Effect of Ice Nuclei on Atmospheric Radiation  

Science Conference Proceedings (OSTI)

A three-dimensional cloud-resolving model (CRM) with observed large-scale forcing is used to study how ice nuclei (IN) affect the net radiative flux at the top of the atmosphere (TOA). In all the numerical experiments carried out, the cloud ice ...

Xiping Zeng; Wei-Kuo Tao; Minghua Zhang; Arthur Y. Hou; Shaocheng Xie; Stephen Lang; Xiaowen Li; David O’C. Starr; Xiaofan Li; Joanne Simpson

2009-01-01T23:59:59.000Z

247

Electroweak structure of light nuclei within chiral effective field theory  

E-Print Network (OSTI)

We review the results of the most recent calculations for the electromagnetic structure of light nuclei, the weak muon capture on deuteron and 3He and the weak proton-proton capture reaction at energies of astrophysical interest, performed within the chiral effective field theory framework.

L. E. Marcucci

2013-11-04T23:59:59.000Z

248

Cluster models for dripline halo nuclei: Achievements and puzzles  

Science Conference Proceedings (OSTI)

Modern Few-Body methods to investigate Borromean two-neutron halo nuclei discussed together with recent experiments. Progress in 6 He and 11 Li studies is analyzed. Some new problems created by large neutron excess and halo phenomenon are under consideration.

B. V. Danilin; I. J. Thompson; M. V. Zhukov; J. S. Vaagen; RNBT (Russian-Nordic-British Theory) Collaboration

2002-01-01T23:59:59.000Z

249

Electric dipole moments of light nuclei from {chi}EFT  

SciTech Connect

I present recent calculations of EDMs of light nuclei using chiral effective field theory techniques. At leading-order, we argue that they can be expressed in terms of six CP-violating low-energy constants. With our expressions, eventual non-zero measurements of EDMs of deuteron, helion, and triton can be combined to disentangle the different sources of CP-violation.

Higa, Renato [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05314-970, Sao Paulo, SP (Brazil)

2013-03-25T23:59:59.000Z

250

Nuclear & Particle Physics Directorate  

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

Nuclear & Particle Physics Directorate Nuclear and Particle Physics (NPP) at BNL comprises the Collider-Accelerator Department (including the NASA Space Radiation Laboratory,...

251

Glossary Term - Beta Particle  

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

Decay Previous Term (Beta Decay) Glossary Main Index Next Term (Bohr Radius) Bohr Radius Beta Particle Beta particles are either electrons or positrons ejected from the nucleus....

252

Glossary Term - Alpha Particle  

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

Decay Previous Term (Alpha Decay) Glossary Main Index Next Term (Atomic Number) Atomic Number Alpha Particle alphaparticle.gif Produced during alpha decay, an alpha particle is a...

253

The Particle Adventure | Glossary  

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

Virtual Particle A particle that exists only for an extremely brief instant in an intermediary process. Then the Heisenberg Uncertainty Principle allows an apparent violation of...

254

The Particle Adventure | Glossary  

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

Annihilation A process in which a particle meets its corresponding antiparticle and both disappear. The energy appears in some other form, perhaps as a different particle and its...

255

The Particle Adventure | Glossary  

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

Chamber The outer layers of a particle detector capable of registering tracks of charged particles. Except for the chargeless neutrinos, only muons reach this layer from the...

256

The Particle Adventure | Glossary  

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

Hadron A particle made of strongly-interacting constituents (quarks andor gluons). These include the meson and baryons. Such particles participate in residual strong interactions...

257

Particle Physics Booklet 2008  

E-Print Network (OSTI)

212 25. Accelerator physics of colliders ? 26. High-energythe full Review. PARTICLE PHYSICS BOOKLET TABLE OF CONTENTSrev. ) Summary Tables of Particle Physics Gauge and Higgs

et al., C. Amsler

2008-01-01T23:59:59.000Z

258

Small Particles, Big Impact  

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

Small Particles, Big Impact Small Particles, Big Impact Small-scale effects of Aerosols Add up Over Time August 24, 2011 | Tags: Climate Research, Earth Sciences, Environmental...

259

Subarctic atmospheric aerosol composition: 3. Measured and modeled properties of cloud condensation nuclei  

SciTech Connect

Predicting the ability of aerosol particles to act as cloud condensation nuclei (CCN) is still a challenge and not properly incorporated in current climate models. By using field data from measurements at the sub-arctic Stordalen site, approximately 200 km north of the Arctic Circle, a hygroscopicity closure study was performed. Measured CCN number concentrations were compared with predictions that involved size distribution data and hygroscopicity data measured by a HTDMA as a proxy for the chemical composition of the aerosol. The sensitivity of the predictions to simplifying assumptions re-garding mixing state of the particles and the temporal variability of the chemical composition were explored. It was found that involving the full growth factor probability density function (GF-PDF) or the averaged growth factor (GF) or a constant averaged ?-value resulted in reasonable agreement be-tween predicted and measured CCN number concentrations. Probability distribution histograms of the performances of the different closure approaches revealed that involving the full GF-PDF resulted in the narrowest and most symmetric distribution of the predicted-to-measured CCN number concentra-tion ratio around unity. While also involving the averaged GF showed a good agreement, the constant averaged ?-value-approach resulted in most of the cases in an overestimation of CCN number con-centrations by ~15 %. Approaches where a constant estimated hygroscopicity was involved predicted CCN number concentrations in some cases well but largely overestimated (assuming internally mixed ammonium sulphate particles) or underestimated (assuming internally mixed organic aerosol particles with ? = 0.1) CCN number concentrations. It is therefore recommended that at least an averaged measured proxy for the aerosol’s chemical composition be incorporated in future CCN predictions and climate models.

Kammermann, Lukas; Gysel, Martin; Weingartner, E.; Herich, Hanna; Holst, Thomas; Cziczo, Daniel J.; Svenningsson, Birgitta; Arneth, Almut; Baltensperger, Urs

2010-02-19T23:59:59.000Z

260

Energy Density Functional for Nuclei and Neutron Stars  

Science Conference Proceedings (OSTI)

Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [ Annu. Rev. Nucl. Part. Sci. 62 485 (2012)]. Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars. Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one. Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of 208Pb and the neutron star radius. Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but it also reproduces expected neutron star data within assumed error bands. This functional is expected to yield more reliable predictions in the region of very neutron rich heavy nuclei.

Erler, J. [UTK/ORNL/German Cancer Research Center-Heidelberg; Horowitz, C. J. [UTK/ORNL/Indiana University; Nazarewicz, Witold [UTK/ORNL/University of Warsaw; Rafalski, M. [UTK/ORNL; Reinhard, P.-G. [Universitat Erlangen, Germany

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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.


261

Physics Out Loud - Particle Resonance  

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

Particle Accelerator Previous Video (Particle Accelerator) Physics Out Loud Main Index Next Video (Photomultiplier Tube) Photomultiplier Tube Particle Resonance How is a particle...

262

Measurements of Cloud Nuclei in the Effluents from Launches of Liquid- and Solid-Fueled Rockets  

Science Conference Proceedings (OSTI)

Airborne measurements of cloud nuclei [cloud condensation nuclei (CCN) and ice nuclei (IN)] were made in the stabilized ground clouds resulting from the launches of a liquid-fueled ATLAS/Centaur rocket and a solid-fueled TITAN III rocket. ...

Edward E. Hindman; Lawrence F. Radke; Mark W. Eltgroth

1982-09-01T23:59:59.000Z

263

An evolutionary Michigan recurrent fuzzy system for nuclei classification in cytological images using nuclear chromatin distribution  

Science Conference Proceedings (OSTI)

Objective: The objective of this research is to carry out the classification of cellular nuclei in cytological pleural fluid images. The article focuses on the feature extraction and classification processes. The extracted feature is a spatial measurement ... Keywords: Cytological images, Genetic algorithm, Nuclei chromatin distribution, Nuclei classification, Pattern recognition, ROC analysis, Recurrent fuzzy system

S. Alayón; J. I. Estévez; J. Sigut; J. L. Sánchez; P. Toledo

2006-12-01T23:59:59.000Z

264

Beta Decay of the Proton-Rich Nuclei 102Sn and 104Sn  

Science Conference Proceedings (OSTI)

The {beta} decays of {sup 102}Sn and {sup 104}Sn were studied by using high-resolution germanium detectors as well as a Total Absorption Spectrometer (TAS). For {sup 104}Sn, with three new {beta}-delayed {gamma}-rays identified, the total Gamow-Teller strength (BGT) value of 2.7(3) was obtained. For {sup 102}Sn, the {gamma}-{gamma} coincidence data were collected for the first time, allowing us to considerably extend the decay scheme. This scheme was used to unfold the TAS data and to deduce a BGT value of 4.2(8) for this decay. This result is compared to shell model predictions, yielding a hindrance factor of 3.6(7) in agreement with those obtained previously for {sup 98}Cd and {sup 100}In. Together with the latter two, {sup 102}Sn completes the triplet of Z {le} 50, N {ge} 50 nuclei with two proton holes, one proton hole and one neutron particle, and two neutron particles with respect to the doubly magic {sup 100}Sn core.

Karny, M. [University of Warsaw; Batist, L. [St. Petersburg Nuclear Physics Institute; Banu, A. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Becker, F. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Blazhev, A. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Brown, B. A. [Michigan State University, East Lansing; Bruchle, W. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Doring, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Faestermann, T. [Technische Universitat Munchen; Gorska, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Grawe, H. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Janas, Z. [University of Warsaw; Jungclaus, A. [Universidad Autonoma de Madrid, Madrid; Kavatsyuk, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kavatsyuk, O. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kirchner, R. [Gesellschaft fur Schwerionenforschung (GSI), Germany; La Commara, M. [Universita Federico II and INFN Napoli; Mandal, S. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Mazzocchi, C. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Miernik, K. [University of Warsaw; Mukha, I. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Muralithar, S. [University of Warsaw; Plettner, C. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Plochocki, A. [University of Warsaw; Roeckl, E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Romoli, M. [Universita Federico II and INFN Napoli; Rykaczewski, Krzysztof Piotr [ORNL; Schadel, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schmidt, K. [University of Warsaw; Schwengner, R. [University of Warsaw; Zylicz, J. [University of Warsaw

2006-01-01T23:59:59.000Z

265

COUNTER PROPAGATION OF ELECTRON AND CO2 LASER BEAMS IN A PLASMA CHANNEL.  

SciTech Connect

A high-energy CO{sub 2} laser is channeled in a capillary discharge. Occurrence of guiding conditions at a relatively low plasma density (<10{sup 18} cm{sup -3}) is confirmed by MHD simulations. Divergence of relativistic electron beam changes depending on the plasma density. Counter-propagation of the electron and laser beams inside the plasma channel results in intense x-ray generation.

HIROSE,T.; POGORELSKY,I.V.; BEN ZVI,I.; YAKIMENKO,V.; KUSCHE,K.; SIDDONS,P.; KUMITA,T.; KAMIYA,Y.; ZIGLER,A.; GREENBERG,B.; ET AL

2002-11-12T23:59:59.000Z

266

Reporting Prescription Drugs, Over-the-Counter Medications, and Dietary Supplements (ORISE 08-NSEM-0227, 2008)  

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

Reporting Reporting Prescription Drugs, Over-the-Counter Medications, and Dietary Supplements Human Reliability Program U.S. Department of Energy Office of Health, Safety and Security Office of Departmental Personnel Security Contents of this brochure are based on 10 CFR Part 712, Human Reliability Program; however, the information presented herein in no way supersedes or has precedence over the provisions of that regulation as published or amended. Table of contents Introduction.......................................................................................................................................1 Prescription drugs .............................................................................................................................1

267

Solar neutrino physics: Sensitivity to light dark matter particles  

E-Print Network (OSTI)

Neutrinos are produced in several neutrino nuclear reactions of the proton-proton chain and carbon-nitrogen-oxygen cycle that take place at different radius of the Sun's core. Hence, measurements of solar neutrino fluxes provide a precise determination of the local temperature. The accumulation of non-annihilating light dark matter particles (with masses between 5 GeV and 16 GeV in the Sun produces a change in the local solar structure, namely, a decrease in the central temperature of a few percent. This variation depends on the properties of the dark matter particles, such as the mass of the particle and its spin-independent scattering cross-section on baryon-nuclei, specifically, the scattering with helium, oxygen, and nitrogen among other heavy elements. This temperature effect can be measured in almost all solar neutrino fluxes. In particular, by comparing the neutrino fluxes generated by stellar models with current observations, namely 8B neutrino fluxes, we find that non-annihilating dark matter particles with a mass smaller than 10 GeV and a spin-independent scattering cross-section with heavy baryon-nuclei larger than 3 x 10^{-37} cm^-2 produce a variation in the 8B neutrino fluxes that would be in conflict with current measurements.

Ilidio Lopes; Joseph Silk

2013-09-29T23:59:59.000Z

268

Study of a Threshold Cherenkov Counter Based on Silica Aerogels with Low Refractive Indices  

E-Print Network (OSTI)

To identify $\\pi^{\\pm}$ and $K^{\\pm}$ in the region of $1.0\\sim 2.5$ GeV/c, a threshold Cherenkov counter equipped with silica aerogels has been investigated. Silica aerogels with a low refractive index of 1.013 have been successfully produced using a new technique. By making use of these aerogels as radiators, we have constructed a Cherenkov counter and have checked its properties in a test beam. The obtained results have demonstrated that our aerogel was transparent enough to make up for loss of the Cherenkov photon yield due to a low refractive index. Various configurations for the photon collection system and some types of photomultipliers, such as the fine-mesh type, for a read out were also tested. From these studies, our design of a Cherenkov counter dedicated to $\\pi / K$ separation up to a few GeV/c %in the momentum range of $1.0 \\sim 2.5$ GeV/c with an efficiency greater than $90$ \\% was considered.

I. Adachi et al

1994-12-13T23:59:59.000Z

269

An array of low-background $^3$He proportional counters for the Sudbury Neutrino Observatory  

E-Print Network (OSTI)

An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active flux of solar neutrinos in the Sudbury Neutrino Observatory (SNO). Data in the third phase of the SNO experiment were collected between November 2004 and November 2006, after the NCD array was added to improve the neutral-current sensitivity of the SNO detector. This array consisted of 36 strings of proportional counters filled with a mixture of $^3$He and CF$_4$ gas capable of detecting the neutrons liberated by the neutrino-deuteron neutral current reaction in the D$_2$O, and four strings filled with a mixture of $^4$He and CF$_4$ gas for background measurements. The proportional counter diameter is 5 cm. The total deployed array length was 398 m. The SNO NCD array is the lowest-radioactivity large array of proportional counters ever produced. This article describes the design, construction, deployment, and characterization of the NCD array, discusses the electronics and data acquisition system, and considers event signatures and backgrounds.

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

2007-05-23T23:59:59.000Z

270

Side-by-Side Comparison of Particle Count and Mass Concentration  

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

Side-by-Side Comparison of Particle Count and Mass Concentration Side-by-Side Comparison of Particle Count and Mass Concentration Measurements in a Residence Title Side-by-Side Comparison of Particle Count and Mass Concentration Measurements in a Residence Publication Type Report Year of Publication 2011 Authors Chan, Wanyu R., and Federico Noris Publisher Lawrence Berkeley National Laboratory City Berkeley Keywords energy analysis and environmental impacts department Abstract Particulate matter (PM) is a contaminant of concern in many indoor environments, including residential and commercial buildings. Health guidelines for exposure to particles are in units of mass concentrations. Relative to time-integrated mass measurements collected on filters, real-time particle counters are less time-consuming to operate. Studies found reasonable correlation between these two measurement techniques, but agreement may vary in different sampling environments, and depends on the instruments used. We performed a side-by-side comparison of particle counts and mass concentrations estimated by three types of real-time instruments: MetOne BT-637 optical particle counter (OPC), TSI DustTrak aerosol monitor, and TSI aerodynamic particle sizer (APS) spectrometer. In addition to these real-time instruments, time-integrated particle mass was also collected using PM2.5 and PM10 Personal Environmental Monitors (PEMs) manufactured by SKC. Sampling was conducted for two consecutive days in an occupied single-family house in Berkeley, California. Concentration profiles had similar trends, with DustTraks reporting higher particle mass concentrations, partially explained by the density value assumed in the calibration. We made assumptions for particle size and density to calculate the PM2.5 and PM10 mass concentrations for the MetOne and APS, and compared with the filter-based measurements. Despite uncertainties and assumptions, there was generally good agreement for the different methods.

271

The Particle Adventure | Particle decays and annihiliations ...  

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

like everyday objects and have momentum, but they also have wave properties. Quantum mechanics, the mathematical basis for our theories about particles, explains the behavior of...

272

The Particle Adventure | Particle decays and annihiliations ...  

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

Particle decays and annihiliations - Electron positron annhiliation When an electron and positron (antielectron) collide at high energy, they can annihilate to produce charm...

273

Unsteady Analysis of a Counter-Rotating Aspirated Compressor Using Phase-Lag and Non-Linear Harmonic Methods.  

E-Print Network (OSTI)

??An analysis of the MIT counter-rotating aspirated compressor (CRAC) has been conducted using two different 3D viscid turbulent unsteady solvers. The Turbo phase-lag time accurate… (more)

Knapke, Robert D.

2011-01-01T23:59:59.000Z

274

The second skin approach : skin strain field analysis and mechanical counter pressure prototyping for advanced spacesuit design  

E-Print Network (OSTI)

The primary aim of this thesis is to advance the theory of advanced locomotion mechanical counter pressure (MCP) spacesuits by studying the changes in the human body shape during joint motion. Two experiments take advantage ...

Bethke, Kristen (Kristen Ann)

2005-01-01T23:59:59.000Z

275

Virtual Monotonic Counters and Count-Limited Objects using a TPM without a Trusted OS (Extended Version)  

E-Print Network (OSTI)

A trusted monotonic counter is a valuable primitive thatenables a wide variety of highly scalable offlineand decentralized applications that would otherwise be prone to replay attacks, including offline payment, e-wallets, ...

Sarmenta, Luis F. G.

2006-09-11T23:59:59.000Z

276

Improving single slope ADC and an example implemented in FPGA with 16.7 GHz equivalent counter clook frequency  

SciTech Connect

Single slope ADC is a common building block in many ASCI or FPGA based front-end systems due to its simplicity, small silicon footprint, low noise interference and low power consumption. In single slope ADC, using a Gray code counter is a popular scheme for time digitization, in which the comparator output drives the clock (CK) port of a register to latch the bits from the Gray code counter. Unfortunately, feeding the comparator output into the CK-port causes unnecessary complexities and artificial challenges. In this case, the propagation delays of all bits from the counter to the register inputs must be matched and the counter must be a Gray code one. A simple improvement on the circuit topology, i.e., feeding the comparator output into the D-port of a register, will avoid these unnecessary challenges, eliminating the requirement of the propagation delay match of the counter bits and allowing the use of regular binary counters. This scheme not only simplifies current designs for low speeds and resolutions, but also opens possibilities for applications requiring higher speeds and resolutions. A multi-channel single slope ADC based on a low-cost FPGA device has been implemented and tested. The timing measurement bin width in this work is 60 ps, which would need a 16.7 GHz counter clock had it implemented with the conventional Gray code counter scheme. A 12-bit performance is achieved using a fully differential circuit making comparison between the input and the ramping reference, both in differential format.

Wu, Jinyuan; /Fermilab; Odeghe, John; /South Carolina State U.; Stackley, Scott; /Boston U.; Zha, Charles; /Rice U.

2011-11-01T23:59:59.000Z

277

Interacting boson models for N{approx}Z nuclei  

Science Conference Proceedings (OSTI)

This contribution discusses the use of boson models in the description of N{approx}Z nuclei. A brief review is given of earlier attempts, initiated by Elliott and co-workers, to extend the interacting boson model of Arima and Iachello by the inclusion of neutron-proton s and d bosons with T = 1 (IBM-3) as well as T = 0 (IBM-4). It is argued that for the N{approx}Z nuclei that are currently studied experimentally, a different approach is needed which invokes aligned neutron-proton pairs with angular momentum J = 2j and isospin T = 0. This claim is supported by an analysis of shell-model wave functions in terms of pair states. Results of this alternative version of the interacting boson model are compared with shell-model calculations in the 1g{sub 9/2} shell.

Van Isacker, P. [Grand Accelerateur National d'Ions Lourds, CEA/DSM-CNRS/IN2P3 BP 55027, F-14076 Caen Cedex 5 (France)

2011-05-06T23:59:59.000Z

278

Exactly Solvable Model for the Decay of Superdeformed Nuclei  

E-Print Network (OSTI)

The history and importance of superdeformation in nuclei is briefly discussed. A simple two-level model is then employed to obtain an elegant expression for the branching ratio for the decay via the E1 process in the normal-deformed band of superdeformed nuclei. From this expression, the spreading width Gamma^downarrow for superdeformed decay is found to be determined completely by experimentally known quantities. The accuracy of the two-level approximation is verified by considering the effects of other normal-deformed states. Furthermore, by using a statistical model of the energy levels in the normal-deformed well, we can obtain a probabilistic expression for the tunneling matrix element V.

B. R. Barrett; D. M. Cardamone; C. A. Stafford

2005-08-19T23:59:59.000Z

279

Mixed-Spin Pairing Condensates in Heavy Nuclei  

Science Conference Proceedings (OSTI)

We show that the Bogoliubov-de Gennes equations for nuclear ground-state wave functions support solutions in which the condensate has a mixture of spin-singlet and spin-triplet pairing. We find that such mixed-spin condensates do not occur when there are equal numbers of neutrons and protons, but only when there is an isospin imbalance. Using a phenomenological Hamiltonian, we predict that such nuclei may occur in the physical region within the proton dripline. We also solve the Bogoliubov-de Gennes equations with variable constraints on the spin-singlet and spin-triplet pairing amplitudes. For nuclei that exhibit this new pairing behavior, the resulting energy surface can be rather soft, suggesting that there may be low-lying excitations associated with the spin mixing.

Gezerlis, Alexandros; Luo, Y. L. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Bertsch, G. F. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1560 (United States)

2011-06-24T23:59:59.000Z

280

Rescattering effects in proton interaction with light neutron rich nuclei  

E-Print Network (OSTI)

Within the framework of the Glauber diffraction theory, the differential cross sections of the elastic p6He, p8Li, and p9Li scattering were calculated at intermediate energies from 70 to 1000 MeV/nucleon. The use of realistic three-body wave functions alpha-n-n (6He), alpha-t-n (8Li) and alpha-t-2n (9Li), obtained in the framework of modern clear models, and the expansion of the Glauber operator into a series of multiple scatterings in a form that is well adapted to the three-body nuclei configuration, allows the calculation of the matrix elements, by taking into account the rescattering from all structure components of the designated nuclei.

E. T. Ibraeva; A. V. Dzhazairov-Kahramanov; O. Imambekov

2013-04-21T23:59:59.000Z

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


281

Do halos exist on the dripline of deformed nuclei?  

E-Print Network (OSTI)

A study of the effect of deformation and pairing on the development of halo nuclei is presented. Exploratory three-body $core+n+n$ calculations show that both the NN interaction and the deformation/excitation of the core hinder the formation of the halo. Preliminary self-consistent mean-field calculations are used to search for regions in the nuclear chart where halos could potentially develop. These are also briefly discussed.

Nunes, F M; Duguet, T

2005-01-01T23:59:59.000Z

282

Density dependence of symmetry free energy of hot nuclei  

E-Print Network (OSTI)

The density and excitation energy dependence of symmetry energy and symmetry free energy for finite nuclei are calculated microscopically in a microcanonical framework taking into account thermal and expansion effects. A finite-range momentum and density dependent two-body effective interaction is employed for this purpose. The role of mass, isospin and equation of state (EoS) on these quantities is also investigated; our calculated results are in consonance with the available experimental data.

S. K. Samaddar; J. N. De; X. Vinas; M. Centelles

2008-04-15T23:59:59.000Z

283

Nuclear forces and ab initio calculations of atomic nuclei  

E-Print Network (OSTI)

Nuclear forces and the nuclear many-body problem have been some of Gerry Brown's main topics in his so productive life as a theoretical physicist. In this talk, I outline how Gerry's work laid the foundations of the modern theory of nuclear forces and ab initio calculations of atomic nuclei. I also present some recent developments obtained in the framework of nuclear lattice simulations.

Meißner, Ulf-G

2014-01-01T23:59:59.000Z

284

Particle Physics Education Sites  

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

쭺-¶ 쭺-¶ Particle Physics Education Sites ¡]¥H¤U¬°¥~¤åºô¯¸¡^ quick reference Education and Information - National Laboratory Education Programs - Women and Minorities in Physics - Other Physics Sites - Physics Alliance - Accelerators at National Laboratories icon Particle Physics Education and Information sites: top Introduction: The Particle Adventure - an interactive tour of particle physics for everyone: the basics of theory and experiment. Virtual Visitor Center of the Stanford Linear Accelerator Center. Guided Tour of Fermilab, - overviews of several aspects of Particle Physics. Also check out Particle Physics concepts. Probing Particles - a comprehensive and straight-forward introduction to particle physics. Big Bang Science - approaches particle physics starting from the theoretical origin of the universe.

285

Laser particle sorter  

DOE Patents (OSTI)

Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

Martin, J.C.; Buican, T.N.

1987-11-30T23:59:59.000Z

286

Chiral Sigma Model with Pion Mean Field in Finite Nuclei  

E-Print Network (OSTI)

The properties of infinite matter and finite nuclei are studied by using the chiral sigma model in the framework of the relativistic mean field theory. We reconstruct an extended chiral sigma model in which the omega meson mass is generated dynamically by the sigma condensation in the vacuum in the same way as the nucleon mass. All the parameters of chiral sigma model are essentially fixed from the hadron properties in the free space. In nuclear matter, the saturation property comes out right, but the incompressibility is too large and the scalar and vector potentials are about a half of the phenomenological ones, respectively. This fact is reflected to the properties of finite nuclei. We calculate N = Z even-even mass nuclei between N = 16 and N = 34. The extended chiral sigma model without the pion mean field leads to the result that the magic number appears at N = 18 instead of N = 20 and the magic number does not appear at N = 28 due to the above mentioned nuclear matter properties. The latter problem, however, could be removed by the introduction of the finite pion mean field with the appearance of the magic number at N = 28. We find that the energy differences between the spin-orbit partners are reproduced by the finite pion mean field which is completely a different mechanism from the standard spin-orbit interaction.

Y. Ogawa; H. Toki; S. Tamenaga; H. Shen; A. Hosaka; S. Sugimoto; K. Ikeda

2003-12-13T23:59:59.000Z

287

Ab-initio self-consistent Gorkov-Green's function calculations of semi-magic nuclei - I. Formalism at second order with a two-nucleon interaction  

E-Print Network (OSTI)

An ab-initio calculation scheme for finite nuclei based on self-consistent Green's functions in the Gorkov formalism is developed. It aims at describing properties of doubly-magic and semi-magic nuclei employing state-of-the-art microscopic nuclear interactions and explicitly treating pairing correlations through the breaking of U(1) symmetry associated with particle number conservation. The present paper introduces the formalism, necessary to undertake applications at (self-consistent) second-order using two-nucleon interactions, in a detailed and self-contained fashion. First applications of such a scheme will be reported soon in a forthcoming publication. Future works will extend the present scheme to include three-nucleon interactions and implement more advanced truncation schemes.

V. Soma; T. Duguet; C. Barbieri

2011-09-28T23:59:59.000Z

288

New Insights into Particle Detection with Superheated Liquids  

E-Print Network (OSTI)

We report new results obtained in calibrations of superheated liquid droplet detectors used in dark matter searches with different radiation sources (n,$\\alpha$,$\\gamma$). In particular, detectors were spiked with alpha-emitters located inside and outside the droplets. It is shown that the responses are different, depending on whether alpha particles or recoil nuclei create the signals. The energy thresholds for $\\alpha$-emitters are compared with test beam measurements using mono-energetic neutrons, as well as with theoretical predictions. Finally a model is presented which describes how the observed intensities of particle induced acoustic signals can be related to the dynamics of bubble growth in superheated liquids. An improved understanding of the bubble dynamics is an important first step in obtaining better discrimination between particle types interacting in detectors of this kind.

S. Archambault; F. Aubin; M. Auger; M. Beleshi; E. Behnke; J. Behnke; B. Beltran; K. Clark; X. Dai; A. Davour; F. Debris. J. Farine; M. -H. Genest; G. Giroux; R. Gornea; R. Faust; H. Hinnefeld; A. Kamaha; C. B. Krauss; M. Lafrenière; M. Laurin; I. Lawson; C. Leroy; C. Lévy; L. Lessard; I. Levine; J. -P. Martin; S. Kumaratunga; R. MacDonald; R. Nadeau; A. Noble; M. -C. Piro; S. Pospisil; N. Starinski; I. Stekl; N. Vander Werf; U. Wichoski; V. Zacek

2010-11-20T23:59:59.000Z

289

Black carbon enrichment in atmospheric ice particle residuals observed in lower tropospheric mixed phase clouds  

SciTech Connect

The enrichment of black carbon (BC) in residuals of small ice crystals was investigated during intensive experiments in winter 2004 and 2005 at the high alpine research station Jungfraujoch (3580 m asl, Switzerland). Two inlets were used to sample the bulk aerosol (residuals of cloud droplets and ice crystals as well as non-activated aerosol particles) and the residual particles of small ice crystals (diameter 5 - 20 ?m). An enrichment of the BC mass fraction in the ice particle residuals was observed by investigating the measured BC mass concentration as a fraction of the bulk (submicrometer) aerosol mass concentration sampled by the two inlets. On average, the BC mass fraction was 5% for the bulk aerosol and 27% for the ice particle residuals. The observed enrichment of BC in ice particle residuals suggests that BC containing particles preferentially act as ice nuclei, with important implications for the indirect aerosol effect via glaciation of clouds.

Cozic, J.; Mertes, S.; Verheggen, B.; Cziczo, Daniel J.; Gallavardin, S. J.; Walter, S.; Baltensperger, Urs; Weingartner, E.

2008-08-15T23:59:59.000Z

290

Black carbon enrichment in atmospheric ice particle residuals observed in lower trophospheric mixed phase clouds  

SciTech Connect

The enrichment of black carbon (BC) in residuals of small ice particles was investigated during intensive experiments in winter 2004 and 2005 at the high alpine research station Jungfraujoch (3580 m asl, Switzerland). Two inlets were used to sample the bulk aerosol (residuals of cloud droplets and ice crystals as well as non-activated aerosol particles) and the residual particles of small ice crystals (diameter 5 - 20 m). An enrichment of the BC mass fraction in the ice particle residuals was observed by investigating the measured BC mass concentration as a fraction of the bulk (submicrometer) aerosol mass concentration sampled by the two inlets. On average, the BC mass fraction was 5% for the bulk aerosol and 14% for the ice particle residuals. The observed enrichment of BC in ice particle residuals suggests that BC may act as ice nuclei, with important implications for the indirect aerosol effect via glaciation of clouds.

Cozic, J.; Mertes, S.; Verheggen, B.; Cziczo, Dan; Gallavardin, S. J.; Walter, S.; Baltensperger, Urs; Weingartner, E.

2008-08-15T23:59:59.000Z

291

Alpha particle production by molecular single-particle effect in reactions of $^{9}$Be just above the Coulomb barrier  

E-Print Network (OSTI)

The $\\alpha $-particle production in the dissociation of $^{9}$Be on $^{209}$Bi and $^{64}$Zn at energies just above the Coulomb barrier is studied within the two-center shell model approach. The dissociation of $^{9}$Be on $^{209}$Bi is caused by a molecular single-particle effect (Landau-Zener mechanism) before the nuclei reach the Coulomb barrier. Molecular single-particle effects do not occur at that stage of the collision for $^{9}$Be+$^{64}$Zn, and this explains the absence of fusion suppression observed for this system. The polarisation of the energy level of the last neutron of $^{9}$Be and, therefore the existence of avoided crossings with that level, depends on the structure of the target.

A. Diaz-Torres; I. J. Thompson; W. Scheid

2004-08-12T23:59:59.000Z

292

The Particle Adventure | Glossary  

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

Fermion Any particle that has odd-half-integer (12, 32, ...) intrinsic angular momentum (spin), measured in units of h-bar. All particles are either fermions or bosons. Fermions...

293

The Particle Adventure | Glossary  

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

Interaction A process in which a particle decays or it responds to a force due to the presence of another particle (as in a collision). The four fundamental interactions are...

294

The Particle Adventure | Glossary  

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

Pauli Exclusion Principle The principle that no two particles in the same quantum state may exist in the same place at the same time. Particles that obey this principle are called...

295

The Particle Adventure | Glossary  

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

Particle A particle with no internal substructure. In the Standard Model the quarks, leptons, photons, gluons, W+ and W- bosons, and the Z bosons are fundamental. All other objects...

296

The Particle Adventure | Glossary  

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

Antiparticle For most particle types (and every fermion type) there is another particle type that has exactly the same mass but the opposite value of all other charges (quantum...

297

SMALL PARTICLE HEAT EXCHANGERS  

E-Print Network (OSTI)

ON ~m Small Particle Heat Exchangers Arion J. Hunt June 1978d. LBL 7841 Small Particle Heat Exchangers by Arlon J. Huntgenerally to non-solar heat exchangers. These may be of the

Hunt, A.J.

2011-01-01T23:59:59.000Z

298

The Particle Adventure  

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

Boson - 2 Finding the Mass of the Higgs Boson - Part 2 Adding up the masses of the particles from the Higgs decay doesn't work, because these particles have enormous kinetic energy...

299

Energy and Mass Dependences of the Parameters of the Semimicroscopic Folding Model for Alpha Particles at Low and Intermediate Energies  

SciTech Connect

The energy and mass dependences of the parameters of the semimicroscopic alpha-particle potential are investigated for the first time in the region of low and intermediate energies. Within the semimicroscopic folding model, both elastic and inelastic differential and total cross sections for reactions on various nuclei are well described by using global parameters obtained in this study.

Kuterbekov, K.A.; Zholdybayev, T.K. [Institute of Nuclear Physics, National Nuclear Center of the Republic of Kazakhstan, Almaty, 480082 (Kazakhstan); Kukhtina, I.N.; Penionzhkevich, Yu.E. [Joint Institute for Nuclear Research, Dubna, Moscow oblast, 141980 (Russian Federation)

2005-06-01T23:59:59.000Z

300

The Particle Adventure | Glossary  

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

Synchrotron A type of circular accelerator in which the particles travel in synchronized bunches at fixed radius...

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


301

The Particle Adventure | Glossary  

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

Fermilab Fermi National Accelerator Laboratory in Batavia, Illinois (near Chicago). Named for particle physics pioneer Enrico Fermi...

302

The Particle Adventure | Glossary  

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

CERN CERN (European Laboratory for Particle Physics) is the major European international accelerator laboratory located near Geneva, Switzerland...

303

The Particle Adventure | Glossary  

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

Tracking The reconstruction of a "track" left in a detector by the passage of a particle through the...

304

Validation of the MCNPX-PoliMi Code to Design a Fast-Neutron Multiplicity Counter  

Science Conference Proceedings (OSTI)

Many safeguards measurement systems used at nuclear facilities, both domestically and internationally, rely on He-3 detectors and well established mathematical equations to interpret coincidence and multiplicity-type measurements for verifying quantities of special nuclear material. Due to resource shortages alternatives to these existing He-3 based systems are being sought. Work is also underway to broaden the capabilities of these types of measurement systems in order to improve current multiplicity analysis techniques. As a part of a Material Protection, Accounting, and Control Technology (MPACT) project within the U.S. Department of Energy's Fuel Cycle Technology Program we are designing a fast-neutron multiplicity counter with organic liquid scintillators to quantify important quantities such as plutonium mass. We are also examining the potential benefits of using fast-neutron detectors for multiplicity analysis of advanced fuels in comparison with He-3 detectors and testing the performance of such designs. The designs are being developed and optimized using the MCNPX-PoliMi transport code to study detector response. In the full paper, we will discuss validation measurements used to justify the use of the MCNPX-PoliMi code paired with the MPPost multiplicity routine to design a fast neutron multiplicity counter with liquid scintillators. This multiplicity counter will be designed with the end goal of safeguarding advanced nuclear fuels. With improved timing qualities associated with liquid scintillation detectors, we can design a system that is less limited by nuclear materials of high activities. Initial testing of the designed system with nuclear fuels will take place at Idaho National Laboratory in a later stage of this collaboration.

J. L. Dolan; A. C. Kaplan; M. Flaska; S. A. Pozzi; D. L. Chichester

2012-07-01T23:59:59.000Z

305

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators and particle detectors - How do we experiment with tiny particles? - How to obtain particles to accelerate Electrons: Heating a metal causes electrons to be ejected. A...

306

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Detector shapes Physicists are curious about the events that occur during and after a particle's...

307

Exposure of Nuclear Track Emulsion to a Mixed Beam of Relativistic $^{12}$N, $^{10}$C, and $^7$Be Nuclei  

E-Print Network (OSTI)

A nuclear track emulsion was exposed to a mixed beam of relativistic $^{12}$N, $^{10}$C, and $^7$Be nuclei having a momentum of 2 GeV/$c$ per nucleon. The beam was formed upon charge exchange processes involving $^{12}$C primary nuclei and their fragmentation. An analysis indicates that $^{10}$C nuclei are dominant in the beam and that $^{12}$N nuclei are present in it. The charge topology of relativistic fragments in the coherent dissociation of these nuclei is presented.

R. R. Kattabekov; K. Z. Mamatkulov; D. A. Artemenkov; V. Bradnova; D. M. Zhomurodov; M. Haiduc; S. P. Kharlamov; V. N. Kondratieva; D. O. Krivenkov; A. I. Malakhov; G. I. Orlova; N. G. Peresadko; Z. A. Igamkulov; N. G. Polukhina; P. A. Rukoyatkin; V. V. Rusakova; R. Stanoeva; S. Vokal; P. I. Zarubin; I. G. Zarubina

2011-04-28T23:59:59.000Z

308

Experimental comparison of the active well coincidence counter with the random driver  

SciTech Connect

A direct comparison has been made between the IAEA Active Well Coincidence Counter (AWCC) and the CMB-8 Random Driver. The comparison included an experimental evaluation of precision, counting rate, accuracy, penetrability, stability, and the effect of sample inhomogeneity. Samples used in the evaluation included highly enriched U/sub 3/O/sub 8/, U/sub 3/O/sub 8/ mixed withe qgraphite, highly enriched uranium metal discs, and depleted uranium metal. These materials are typical of the samples of interest to the IAEA inspectors. It was concluded that the two instruments had very similar performance characteristics with the Random Driver giving better penetrability and the AWCC giving better stability.

Menlove, H.O.; Ensslin, N.; Sampson, T.E.

1979-06-01T23:59:59.000Z

309

Performance of Multi-Pixel Photon Counters for the T2K near detectors  

E-Print Network (OSTI)

We have developed a Multi-Pixel Photon Counter (MPPC) for the neutrino detectors of T2K experiment. About 64,000 MPPCs have been produced and tested in about a year. In order to characterize a large number of MPPCs, we have developed a system that simultaneously measures 64 MPPCs with various bias voltage and temperature. The performance of MPPCs are found to satisfy the requirement of T2K experiment. In this paper, we present the performance of 17,686 MPPCs measured at Kyoto University.

Yokoyama, M; Gomi, S; Ieki, K; Nagai, N; Nakaya, T; Nitta, K; Orme, D; Otani, M; Murakami, T; Nakadaira, T; Tanaka, M

2010-01-01T23:59:59.000Z

310

Excitation of Accelerating Plasma Waves by Counter-propagating Laser Beams  

SciTech Connect

Generation of accelerating plasma waves using two counter-propagating laser beams is considered. Colliding-beam accelerator requires two laser pulses: the long pump and the short timing beam. We emphasize the similarities and differences between the conventional laser wakefield accelerator and the colliding-beam accelerator (CBA). The highly nonlinear nature of the wake excitation is explained using both nonlinear optics and plasma physics concepts. Two regimes of CBA are considered: (i) the short-pulse regime, where the timing beam is shorter than the plasma period, and (ii) the parametric excitation regime, where the timing beam is longer than the plasma period. Possible future experiments are also outlined.

Gennady Shvets; Nathaniel J. Fisch; and Alexander Pukhov

2001-08-30T23:59:59.000Z

311

Performance of Multi-Pixel Photon Counters for the T2K near detectors  

E-Print Network (OSTI)

We have developed a Multi-Pixel Photon Counter (MPPC) for the neutrino detectors of T2K experiment. About 64,000 MPPCs have been produced and tested in about a year. In order to characterize a large number of MPPCs, we have developed a system that simultaneously measures 64 MPPCs with various bias voltage and temperature. The performance of MPPCs are found to satisfy the requirement of T2K experiment. In this paper, we present the performance of 17,686 MPPCs measured at Kyoto University.

M. Yokoyama; A. Minamino; S. Gomi; K. Ieki; N. Nagai; T. Nakaya; K. Nitta; D. Orme; M. Otani; T. Murakami; T. Nakadaira; M. Tanaka

2010-07-16T23:59:59.000Z

312

Development and commissioning of the Timing Counter for the MEG Experiment  

E-Print Network (OSTI)

The Timing Counter of the MEG (Mu to Electron Gamma) experiment is designed to deliver trigger information and to accurately measure the timing of the $e^+$ in searching for the decay $\\mu^+ \\rightarrow e^+\\gamma$. It is part of a magnetic spectrometer with the $\\mu^+$ decay target in the center. It consists of two sectors upstream and downstream the target, each one with two layers: the inner one made with scintillating fibers read out by APDs for trigger and track reconstruction, the outer one consisting in scintillating bars read out by PMTs for trigger and time measurement. The design criteria, the obtained performances and the commissioning of the detector are presented herein.

M. De Gerone; S. Dussoni; K. Fratini; F. Gatti; R. Valle; G. Boca; P. W. Cattaneo; R. Nardò; M. Rossella; L. Galli; M. Grassi; D. Nicolò; Y. Uchiyama; D. Zanello

2011-12-01T23:59:59.000Z

313

Calibration and performance testing of the IAEA Aquila Active Well Coincidence Counter (Unit 1)  

SciTech Connect

An Active Well Coincidence Counter (AWCC) and a portable shift register (PSR-B) produced by Aquila Technologies Group, Inc., have been tested and cross-calibrated with existing AWCCs used by the International Atomic Energy Agency (IAEA). This report summarizes the results of these tests and the cross-calibration of the detector. In addition, updated tables summarizing the cross-calibration of existing AWCCs and AmLi sources are also included. Using the Aquila PSR-B with existing IAEA software requires secondary software also supplied by Aquila to set up the PSR-B with the appropriate measurement parameters.

Menlove, H.O..; Siebelist, R.; Wenz, T.R.

1996-01-01T23:59:59.000Z

314

Riding Waves of Dissent: Counter-Imperial Impulses in the Age of Fuller and Melville  

E-Print Network (OSTI)

This dissertation examines the interplay between antebellum frontier literature and the counter-imperial impulses that impelled the era's political, cultural, and literary developments. Focusing on selected works by James Fenimore Cooper, Margaret Fuller, Francis Parkman, and Herman Melville, I use historicist methods to reveal how these authors drew upon and contributed to a strong and widespread, though ultimately unsuccessful, resistance to the discourse of Manifest Destiny that now identifies the age. For all their important differences, each of the frontier writings I examine reflects the presence of a culturally-pervasive anxiety over issues such as environmental depletion, slavery, Indian removal, and expansion's impact on the character of a nation ostensibly founded on republican, anti-imperialist principles. Moreover, the later works reflect an intensification of such anxiety as the United States entered into war with Mexico and the slavery debate came to increasingly dominate the political scene. Chapter I emphasizes the ideological contestations bred by the antebellum United States' westward march, and signals a departure from recent critical tendencies to omit those contestations in order to portray a more stable narrative of American imperialism. The chapter concludes by arguing that Cooper established an initial narrative formulation that sought to suppress counter-imperial impulses within a mainline triumphalist vision. Chapter II examines Fuller's first published book, Summer on the Lakes, in 1843, in the context of hotbutton controversies over expansion that informed the 1844 presidential contest; employing the metaphor of the dance as her governing trope for engaging unfamiliar landscapes, peoples, and even modes of community, Fuller placed persistently marginalized counter-imperial impulses at the center of her western travelogue. Chapter III discusses Parkman's sub-textual engagement with controversies surrounding the Mexican War; though thoroughly invested in conquest ideologies, Oregon Trail nevertheless resonates with the war's most popular negative associations. Chapter IV explores Melville's attunement to national ambivalences towards rhetorics of Manifest Destiny from the late 1840s through the early 1850s. During this stage of his career, Melville both payed tribute to the Anglo-American triumphalism freighting the antebellum era, and enacted a powerful articulation of the era's counter-imperial impulse.

Lawrence, Nicholas M.

2009-08-01T23:59:59.000Z

315

The Particle Adventure | Particle decays and annihiliations ...  

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

Particle decays and annihiliations - Half life A lump of uranium left to itself will gradually decay, one nucleus at a time. The rate of decay is measured by how long it would take...

316

The Particle Adventure | Particle decays and annihiliations ...  

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

mass in a radioactive decay go? Recall that we said that when uranium decays into thorium and an alpha particle, 0.0046 u of mass appears to have been lost. As Einstein said,...

317

Size and time-resolved growth rate measurements of 1 to 5 nm freshly formed atmospheric nuclei  

SciTech Connect

This study presents measurements of size and time-resolved particle diameter growth rates for freshly nucleated particles down to 1 nm geometric diameter. Novel data analysis methods were developed, de-coupling for the first time the size and time-dependence of particle growth rates by fitting the aerosol general dynamic equation to size distributions obtained at an instant in time. Size distributions of freshly nucleated total aerosol (neutral and charged) were measured during two intensive measurement campaigns in different environments (Atlanta, GA and Boulder, CO) using a recently developed electrical mobility spectrometer with a diethylene glycol-based ultrafine condensation particle counter as the particle detector. One new particle formation (NPF) event from each campaign was analyzed in detail. At a given instant in time during the NPF event, size-resolved growth rates were obtained directly from measured size distributions and were found to increase approximately linearly with particle size from {approx}1 to 3 nm geometric diameter, increasing from 5.5 {+-} 0.8 to 7.6 {+-} 0.6 nm h{sup -1} in Atlanta (13:00) and from 5.6 {+-} 2 to 27 {+-} 5 nm h{sup -1} in Boulder (13:00). The resulting growth rate enhancement {Lambda}, defined as the ratio of the observed growth rate to the growth rate due to the condensation of sulfuric acid only, was found to increase approximately linearly with size from {approx}1 to 3 nm geometric diameter. For the presented NPF events, values for {Lambda} had lower limits that approached {approx}1 at 1.2 nm geometric diameter in Atlanta and {approx}3 at 0.8 nm geometric diameter in Boulder, and had upper limits that reached 8.3 at 4.1 nm geometric diameter in Atlanta and 25 at 2.7 nm geometric diameter in Boulder. Nucleated particle survival probability calculations comparing the effects of constant and size-dependent growth indicate that neglecting the strong dependence of growth rate on size from 1 to 3 nm observed in this study could lead to a significant overestimation of CCN survival probability.

Kuang C.; Chen, M.; Zhao, J.; Smith, J.; McMurry, P. H.; Wang, J.

2012-04-12T23:59:59.000Z

318

Physics Out Loud - Particle Accelerator  

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

Nucleus Previous Video (Nucleus) Physics Out Loud Main Index Next Video (Particle Resonance) Particle Resonance Particle Accelerator Andrew Hutton, Director of Accelerators at...

319

SPARC: The Stored Particle Atomic Research Collaboration At FAIR  

Science Conference Proceedings (OSTI)

The future international accelerator Facility for Antiproton and Ion Research (FAIR) encompasses 4 scientific pillars containing at this time 14 approved technical proposals worked out by more than 2000 scientists from all over the world. They offer a wide range of new and challenging opportunities for atomic physics research in the realm of highly-charged heavy ions and exotic nuclei. As one of the backbones of the Atomic, Plasma Physics and Applications (APPA) pillar, the Stored Particle Atomic Physics Research Collaboration (SPARC) has organized tasks and activities in various working groups for which we will present a concise survey on their current status.

Stoehlker, Th. [Helmholtz-Zentrum fuer Schwerionenforschung GSI, Darmstadt (Germany); Helmholtz-Institut Jena, Jena (Germany); Physikalisches Institut, Ruprecht-Karls Universitaet Heidelberg (Germany); ExtreMe Matter Institute EMMI and Research Division, Helmholtz-Zentrum fuer Schwerionenforschung GSI, Darmstadt (Germany); Beyer, H. F.; Braeuning-Demian, A.; Brandau, C.; Herfurth, F.; Kozhuharov, Ch.; Kuehl, Th.; Liesen, D.; Litvinov, Yu.; Noertershaeuser, W.; Kester, O.; Quint, W.; Spillmann, U.; Winters, D. [Helmholtz-Zentrum fuer Schwerionenforschung GSI, Darmstadt (Germany); Gumberidze, A. [ExtreMe Matter Institute EMMI and Research Division, Helmholtz-Zentrum fuer Schwerionenforschung GSI, Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, Johann Wolfgang Goethe Universitaet Frankfurt (Germany); Grisenti, R. E.; Petridis, N. [Institut fuer Kernphysik, Johann Wolfgang Goethe Universitaet Frankfurt (Germany); Hagmann, S. [Helmholtz-Zentrum fuer Schwerionenforschung GSI, Darmstadt (Germany); Institut fuer Kernphysik, Johann Wolfgang Goethe Universitaet Frankfurt (Germany); Maertin, R. [Helmholtz-Zentrum fuer Schwerionenforschung GSI, Darmstadt (Germany); Physikalisches Institut, Ruprecht-Karls Universitaet Heidelberg (Germany); Schramm, U. [FZD Forschungszentrum Dresden- Rossendorf (Germany)

2011-06-01T23:59:59.000Z

320

Adhesive particle shielding  

DOE Patents (OSTI)

An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

Klebanoff, Leonard Elliott (Dublin, CA); Rader, Daniel John (Albuquerque, NM); Walton, Christopher (Berkeley, CA); Folta, James (Livermore, CA)

2009-01-06T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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321

Negative heat capacities and first order phase transitions in nuclei  

E-Print Network (OSTI)

Anomalous negative heat capacities have been claimed as indicators of first order phase transitions in finite systems in general, and fornuclear systems in particular. A thermodynamic approach allowing for all Q value terms is used to evaluate heat capacities in finitevan der Waals fluids and finite lattice systems in the coexistence region. Fictitious large effects and negative heat capacities are observed in lattice systems when periodic boundary conditions are introduced. Small anomalous effects are predicted for small drops and for finite lattice systems. A straightforward application of the analysis to nuclei shows that negative heat capacities cannot be observed for A>60.

L. G. Moretto; J. B. Elliott; L. Phair; G. J. Wozniak

2002-08-13T23:59:59.000Z

322

Semi-inclusive inelastic electron scattering from nuclei  

SciTech Connect

A survey is presented of the physics of the electroproduction of hadrons from nuclear targets, eA ..-->.. e'hX. Variables and structure functions are specified. The parton model description of electroproduction is summarized; fragmentation functions are defined and their properties are listed. Specific measurements are suggested. Predictions of the pion exchange model are presented for the nuclear dependence of eA ..-->.. e'hX, including a discussion of the special subprocess e..pi.. ..-->.. e'..pi.. in which scattering occurs from the pion constituents of nuclei.

Berger, E.L.

1987-04-30T23:59:59.000Z

323

Liquid-gas phase transition in finite nuclei  

E-Print Network (OSTI)

In a finite temperature Thomas-Fermi framework, we calculate density distributions of hot nuclei enclosed in a freeze-out volume of few times the normal nuclear volume and then construct the caloric curve, with and without inclusion of radial collective flow. In both cases, the calculated specific heats $C_v$ show a peaked structure signalling a liquid-gas phase transition. Without flow, the caloric curve indicates a continuous phase transition whereas with inclusion of flow, the transition is very sharp. In the latter case, the nucleus undergoes a shape change to a bubble from a diffuse sphere at the transition temperature.

J. N. De; S. K. Samaddar; S. Shlomo

1997-10-07T23:59:59.000Z

324

How to Measure the Spreading Width of Superdeformed Nuclei  

Science Conference Proceedings (OSTI)

A new expression for the branching ratio for the decay via the E1 process in the normal-deformed band of superdeformed nuclei is given within a simple two-level model. Using this expression, the spreading or tunneling width {gamma}{down_arrow} for superdeformed decay can be expressed entirely in terms of experimentally known quantities. We show how to determine the tunneling matrix element V from the measured value of {gamma}{down_arrow} and a statistical model of the energy levels.

Cardamone, D.M.; Stafford, C.A.; Barrett, B.R. [Department of Physics, University of Arizona, Tucson, AZ 85721 (United States)

2004-09-13T23:59:59.000Z

325

Excitation energy dependence of symmetry energy of finite nuclei  

E-Print Network (OSTI)

A finite range density and momentum dependent effective interaction is used to calculate the density and temperature dependence of the symmetry energy coefficient Csym(rho,T) of infinite nuclear matter. This symmetry energy is then used in the local density approximation to evaluate the excitation energy dependence of the symmetry energy coefficient of finite nuclei in a microcanonical formulation that accounts for thermal and expansion effects. The results are in good harmony with the recently reported experimental data from energetic nucleus-nucleus collisions.

S. K. Samaddar; J. N. De; X. Vinas; M. Centelles

2007-06-22T23:59:59.000Z

326

Thermalization in collisions of large nuclei at high energies  

E-Print Network (OSTI)

Hydrodynamical analysis of experimental data of ultrarelativistic heavy ion collisions seems to indicate that the hot QCD matter created in the collisions thermalizes very quickly. Theoretically, we have no idea why this should be true. In this proceeding, I will describe how the thermalization takes place in the most theoretically clean limit -- that of large nuclei at asymptotically high energy per nucleon, where the system is described by weak-coupling QCD. In this limit, plasma instabilities dominate the dynamics from immediately after the collision until well after the plasma becomes nearly in equilibrium at time t \\alpha^(-5/2)Q^(-1).

Kurkela, Aleksi

2013-01-01T23:59:59.000Z

327

Suppressed fusion cross section for neutron halo nuclei  

E-Print Network (OSTI)

Fusion reactions of neutron-halo nuclei are investigated theoretically with a three-body model. The time-dependent wave-packet method is used to solve the three-body Schrodinger equation. The halo neutron behaves as a spectator during the Coulomb dissociation process of the projectile. The fusion cross sections of 11Be-209Bi and 6He-238U are calculated and are compared with measurements. Our calculation indicates that the fusion cross section is slightly hindered by the presence of weakly bound neutrons.

Makoto Ito; Kazuhiro Yabana; Takashi Nakatsukasa; Manabu Ueda

2005-06-23T23:59:59.000Z

328

Risk assessment methodology applied to counter IED research & development portfolio prioritization  

SciTech Connect

In an effort to protect the United States from the ever increasing threat of domestic terrorism, the Department of Homeland Security, Science and Technology Directorate (DHS S&T), has significantly increased research activities to counter the terrorist use of explosives. More over, DHS S&T has established a robust Counter-Improvised Explosive Device (C-IED) Program to Deter, Predict, Detect, Defeat, and Mitigate this imminent threat to the Homeland. The DHS S&T portfolio is complicated and changing. In order to provide the ''best answer'' for the available resources, DHS S&T would like some ''risk based'' process for making funding decisions. There is a definite need for a methodology to compare very different types of technologies on a common basis. A methodology was developed that allows users to evaluate a new ''quad chart'' and rank it, compared to all other quad charts across S&T divisions. It couples a logic model with an evidential reasoning model using an Excel spreadsheet containing weights of the subjective merits of different technologies. The methodology produces an Excel spreadsheet containing the aggregate rankings of the different technologies. It uses Extensible Logic Modeling (ELM) for logic models combined with LANL software called INFTree for evidential reasoning.

Shevitz, Daniel W [Los Alamos National Laboratory; O' Brien, David A [Los Alamos National Laboratory; Zerkle, David K [Los Alamos National Laboratory; Key, Brian P [Los Alamos National Laboratory; Chavez, Gregory M [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

329

Nucleation and Growth of Atmospheric Particles  

SciTech Connect

New particle formation (NPF) in the atmospheric is a two-step process: Nucleation leads to the birth of stable nuclei that subsequently grow to sizes that can be detected and affect the atmosphere’s radiative properties. Our group is studying both of these processes. Our nucleation research is largely supported by NSF and involves measurements of neutral molecular clusters formed by nucleation with a new custom-designed mass spectrometer (the Cluster-CIMS) and measurements of nanoparticle size distributions as small as 1 nm with a new aerosol spectrometer (the DEG SMPS). These measurements are providing new insights into aspects of cluster behavior that affect nucleation rates. The U.S. DOE supports our research on nanoparticle growth rates. This research couples physical and chemical measurements of aerosol properties and behavior. The TDCIMS, which enables real-time measurements of composition for freshly nucleated particles as small as 8 nm and was developed with support from DOE, is the most important tool in this work. Our most important discoveries about processes that affect growth rates are summarized in a recent PNAS article (doi:10.1073/pnas.0912127107). In short, this work has shown that alkylammonium-carboxylate salts, formed, for example, by reactions between amines and carboxylic acids, account for 20–50% of the mass of freshly nucleated particles in locations that include Atlanta, Mexico City, Boulder, and Hyytiälä, while sulfates account for only about 10%. These newly discovered compounds help to explain the high growth rates of freshly nucleated particles that have been observed around the globe and help to explain why nucleation is an important atmospheric process, not just a scientific curiosity. Our poster will provide an overview of this work.

McMurry, P.; Kuang, C.; Barsanti, K.; Eisele, F.; Friedli, H.; Scheckman, J.; Titcombe, M.; Williams, B.; Zhao, J.; Smith, J.

2010-03-15T23:59:59.000Z

330

Fission decay of N = Z nuclei at high angular momentum: $^{60}$Zn  

E-Print Network (OSTI)

Using a unique two-arm detector system for heavy ions (the BRS, binary reaction spectrometer) coincident fission events have been measured from the decay of $^{60}$Zn compound nuclei formed at 88MeV excitation energy in the reactions with $^{36}$Ar beams on a $^{24}$Mg target at $E_{lab}(^{36}$Ar) = 195 MeV. The detectors consisted of two large area position sensitive (x,y) gas telescopes with Bragg-ionization chambers. From the binary coincidences in the two detectors inclusive and exclusive cross sections for fission channels with differing losses of charge were obtained. Narrow out-of-plane correlations corresponding to coplanar decay are observed for two fragments emitted in binary events, and in the data for ternary decay with missing charges from 4 up to 8. After subtraction of broad components these narrow correlations are interpreted as a ternary fission process at high angular momentum through an elongated shape. The lighter mass in the neck region consists dominantly of two or three-particles. Differential cross sections for the different mass splits for binary and ternary fission are presented. The relative yields of the binary and ternary events are explained using the statistical model based on the extended Hauser-Feshbach formalism for compound nucleus decay. The ternary fission process can be described by the decay of hyper-deformed states with angular momentum around 45-52 $hbar$.

W. Von Oertzen; V. Zherebchevsky; B. Gebauer; C. Schulz; S. Thummerer; D. Kamanin; G. Royer; T. Wilpert

2008-11-03T23:59:59.000Z

331

ON THE SIMULTANEOUS GENERATION OF HIGH-ENERGY EMISSION AND SUBMILLIMETER/INFRARED RADIATION FROM ACTIVE GALACTIC NUCLEI  

Science Conference Proceedings (OSTI)

For active galactic nuclei (AGNs), we study the role of the mechanism of quasi-linear diffusion (QLD) in producing the high-energy emission in the MeV-GeV domains strongly connected with the submillimeter/infrared radiation. Considering the kinetic equation governing the stationary regime of the QLD, we investigate the feedback of the diffusion on electrons. We show that this process leads to the distribution of particles by pitch angles, implying that the synchrotron mechanism is no longer prevented by energy losses. Examining a reasonable interval of physical parameters, we show that it is possible to produce MeV-GeV {gamma}-rays that are strongly correlated with submillimeter/infrared bands.

Osmanov, Z., E-mail: z.osmanov@iliauni.edu.g [Centre for Theoretical Astrophysics, ITP, Ilia State University, Kazbegi Str. 2a, 0160 Tbilisi (Georgia)

2010-09-20T23:59:59.000Z

332

Delayed-fission properties of neutron-deficient americium nuclei  

Science Conference Proceedings (OSTI)

Characteristics of the delayed-fission decay mode in light americium nuclei have been investigated. Measurements on the unknown isotopes {sup 230}Am and {sup 236}Am were attempted, and upper limits on the delayed-fission branches of these nuclei were determined. Evidence of the existence of {sup 236}Am was observed in radiochemical separations. Total kinetic energy and mass-yield distributions of the electron-capture delayed-fission mode were measured for {sup 232}Am (t{sub 1/2} = 1.31 {plus minus} 0.04 min) and for {sup 234}Am (t{sub 1/2} = 2.32 {plus minus} 0.08 min), and delayed-fission probabilities of 6.9 {times} 10{sup {minus}4} and 6.6 {times} 10{sup {minus}5}, respectively, were determined. The total kinetic energy and the asymmetric mass-yield distributions are typical of fission of mid-range actinides. No discernible influence of the anomalous triple-peaked mass division characteristic of the thorium-radium region was detected. Measurements of the time correlation between the electron-capture x-rays and the subsequent fission conform that the observed fissions arise from the electron-capture delayed-fission mechanism. Delayed fission has provided a unique opportunity to extend the range of low-energy fission studies to previously inaccessible regions. 71 refs., 44 figs., 13 tabs.

Hall, H.L. (California Univ., Berkeley, CA (USA). Dept. of Chemistry)

1989-10-23T23:59:59.000Z

333

Initial characterization of unequal-length, low-background proportional counters for absolute gas-counting applications  

Science Conference Proceedings (OSTI)

Characterization of two sets of custom unequal length proportional counters is underway at Pacific Northwest National Laboratory (PNNL). These detectors will be used in measurements to determine the absolute activity concentration of gaseous radionuclides (e.g. 37 Ar ). A set of three detectors has been fabricated based on previous PNNL ultra-low-background proportional counter designs and now operate in PNNL's shallow underground counting laboratory. A second set of four counters has also been fabricated using clean assembly of Oxygen-Free High-Conductivity copper components for use in a shielded above-ground counting laboratory. Characterization of both sets of detectors is underway with measurements of background rates

2013-01-01T23:59:59.000Z

334

Significant role of deformation in probing postsaddle nuclear dissipation with light particle emission  

Science Conference Proceedings (OSTI)

Using a one-dimensional Langevin model, we study the effects of deformation on the multiplicities of postsaddle neutrons, protons, alpha particles, and giant dipole resonance (GDR) gamma rays of a heavy fissioning system {sup 240}Cf as probes of postsaddle nuclear dissipation (beta). It is shown that postsaddle dissipation effects on these light particles have a significant deformation dependence. Furthermore, we find that the role of deformation depends on the type of the particle. It reduces the sensitive influence of beta on protons, alpha particles, and GDR gamma rays substantially, whereas it enhances the sensitivity of neutrons to beta. The results suggest that to accurately extract the postsaddle friction strength by comparing measured prescission particle multiplicities of heavy nuclei with calculations based on statistical models or stochastic equations like Langevin equations, it is important to take into account the deformation effects. The influence of model dimensionality is discussed.

Ye, W. [Department of Physics, Southeast University, Nanjing 210096, Jiangsu Province (China)

2010-05-15T23:59:59.000Z

335

P-odd and P-even correlations for third particles in ternary fission  

Science Conference Proceedings (OSTI)

Within quantum-mechanical fission theory, P-odd and P-even correlations in angular distributions of products of the ternary fission of nuclei that is induced by polarized cold and thermal neutrons are investigated on the basis of a nonevaporative mechanism of third-particle emission and under the assumption that a two-humped fission barrier exists. It is shown that these correlations for third particles are induced by the analogous correlations for ternary-fission fragments, the latter being transferred to the third particle because of the kinematical conditions of third-particle emission that are associated with the charge and mass asymmetry of fragments. Optimum methods for observing the above correlations for third particles are discussed. The possibility of discovering the emission of prescission neutrons in the fission process against the background of evaporated neutrons by means of studying P-odd and P-even correlations is explored.

Bunakov, V. E., E-mail: bunakov@vb13190.spbu.edu; Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Titova, L. V. [Russian Academy of Sciences, Petersburg Nuclear Physics Institute (Russian Federation)

2008-12-15T23:59:59.000Z

336

Surrogate protein particle standards  

Science Conference Proceedings (OSTI)

... The large particles may be useful as a standard for the counting of ... drugs require visual inspection, at present there are no standards available for ...

2013-09-10T23:59:59.000Z

337

Nuclear & Particle Physics Directorate  

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

at RHIC or the AGS should be submitted to the Associate Laboratory Director for Nuclear and Particle Physics, presently Steve Vigdor, Bldg. 510F, Brookhaven National...

338

Nuclear & Particle Physics Directorate  

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

Brookhaven National Laboratory Nuclear and Particle Physics Program Advisory Committee Meeting 12-14 September 2006 Tuesday, 12 September Room 2-160, Bldg. 510 (Physics) 0900...

339

Nuclear & Particle Physics Directorate  

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

Brookhaven National Laboratory Nuclear and Particle Physics Program Advisory Committee Meeting June 15-16, 2009 Agenda Reference Documents Letter to Barbara Jacak and Nu Xu (129...

340

Nuclear & Particle Physics Directorate  

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

Brookhaven National Laboratory Nuclear and Particle Physics Program Advisory Committee Meeting 7-8 June 2012 Agenda Related Documents: PHENIX Beam Use Proposal, STAR Beam Use...

Note: This page contains sample records for the topic "nuclei particle counter" 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

The Particle Adventure | Glossary  

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

Charge Conservation The observation that electric charge is conserved in any process of transformation of one group of particles into another...

342

The Particle Adventure | Glossary  

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

Standard Model Physicists have developed a theory of fundamental particles and interactions called the Standard Model. This site describes various aspects of this model...

343

The Particle Adventure | Glossary  

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

Weak Interaction The interaction responsible for all processes in which flavor changes, hence for the instability of heavy quarks and leptons, and particles that contain them. Weak...

344

The Particle Adventure | Glossary  

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

Antimatter Material made from antifermions. We define the fermions that are common in our universe as matter and their antiparticles as antimatter. In the particle theory there is...

345

The Particle Adventure | Glossary  

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

Z Boson A carrier particle of the weak interactions. It is involved in all weak processes that do not change flavor...

346

The Particle Adventure | Glossary  

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

W+, W- Boson A carrier particle of the weak interactions. It is involved in all electric-charge-changing weak processes...

347

The Particle Adventure | Glossary  

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

Accelerator A machine used to accelerate particles to high speeds, and thus high energy compared to their rest-mass energy...

348

The Particle Adventure | Glossary  

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

Conservation When a quantity is always the same before and after a particle reaction, it is said to be conserved. Such quantities include electric charge, energy, and momentum...

349

Particle Event Pictures  

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

- Identifying Particles - D0 Detector - CDF Detector - Links Project Contact: Thomas Jordan - jordant@fnal.gov Web Maintainer: qnet-webmaster@fnal.gov Last Update: April 13, 2001...

350

The Particle Adventure | Glossary  

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

Electron The least massive electrically-charged particle, hence absolutely stable. It is the most common lepton, with electric charge -1...

351

The Particle Adventure  

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

The discovery of the Higgs boson is an enormous clue about the mechanism for giving mass to fundamental particles, as conceived by Higgs, Brout, Englert, Guralnik, Hagen, and...

352

FPGA particle graphics hardware.  

E-Print Network (OSTI)

??Particle graphics simulations are well suited for modeling phenomena such as water, cloth, explosions, fire, smoke, and clouds. They are normally realized in software, as… (more)

Beeckler, John Sachs.

2006-01-01T23:59:59.000Z

353

Particle Data Group - Products  

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

Group HOME: pdgLive Summary Tables Reviews, Tables, Plots Particle Listings Europe, Africa, Middle East, India, Pakistan, Russia and all other countries For copies of: ...

354

Particle Physics Education Sites  

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

Particle Physics Education Sites quick reference Education and Information - National Laboratory Education Programs - Women and Minorities in Physics - Other Physics Sites -...

355

Hybrid simulation of energetic particle effects on tearing modes in tokamak plasmas  

SciTech Connect

The effects of energetic ions on stability of tearing mode are investigated by global kinetic/MHD hybrid simulations in a low beta tokamak plasma. The kinetic effects of counter circulating energetic ions from the non-adiabatic response are found to be strongly destabilizing while the effects from the adiabatic response are stabilizing. The net effect with both adiabatic and non-adiabatic contributions is destabilizing. On the other hand, the kinetic effects of co-circulating energetic ions from the non-adiabatic response are calculated to be weakly stabilizing while the corresponding adiabatic contribution is destabilizing for small energetic ion beta. The net effect is weakly stabilizing. The dependence of kinetic effects on energetic ion beta, gyroradius, and speed is studied systematically and the results agree in large part with the previous analytic results for the kinetic effects of circulating particles. For trapped energetic ions, their effects on tearing mode stability are dominated by the adiabatic response due to large banana orbit width and strong poloidal variation of particle pressure. The net effect of trapped energetic particles on tearing modes is much more destabilizing as compared to that of counter circulating particles at the same beta value.

Cai Huishan [CAS Key Laboratory of Geospace Environment, Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Fu Guoyong [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2012-07-15T23:59:59.000Z

356

Synthesis and textural evolution of alumina particles with mesoporous structures  

Science Conference Proceedings (OSTI)

Alumina particles with mesostructures were synthesized through a chemical precipitation method by using different inorganic aluminum salts followed by a heterogeneous azeotropic distillation and calcination process. The obtained mesoporous {gamma}-alumina particles were systematically characterized by the X-ray diffraction, transmission electron microscopy and nitrogen adsorption-desorption measurement. Effects of the aluminum salt counter anion, pH value and the azeotropic distillation process on the structural or textural evolution of alumina particles were investigated. It is found that Cl{sup -} in the reaction solution can restrain the textural evolution of the resultant precipitates into two-dimensional crystallized pseudoboehmite lamellae during the heterogeneous azeotropic distillation, and then transformed into {gamma}-Al{sub 2}O{sub 3} particles with mesostructures after further calcination at 1173 K, whereas coexisting SO{sub 4}{sup 2-} can promote above morphology evolution and then transformed into {gamma}-Al{sub 2}O{sub 3} nanofibers after calcination at 1173 K. Moreover nearly all materials retain relatively high specific surface areas larger than 100 m{sup 2} g{sup -1} even after calcinations at 1173 K. - Graphical abstract: Co-existing Cl{sup -} is beneficial for the formation of {gamma}-alumina nanoparticles with mesostructures during the precipitation process. Interparticle and intraparticle mesopores can be derived from acidic solution and near neutral solution, respectively.

Liu Xun [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Peng Tianyou, E-mail: typeng@whu.edu.c [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Yao Jinchun; Lv Hongjin; Huang Cheng [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China)

2010-06-15T23:59:59.000Z

357

Localized orientational order chaperons the nucleation of Rotator phases in hard polyhedral particles  

E-Print Network (OSTI)

The nucleation kinetics of the rotator phase in hard cuboctahedra, truncated octahedra, and rhombic dodecahedra is simulated via a combination of Forward Flux Sampling and Umbrella Sampling. For comparable degree of supersaturation, the polyhedra are found to have significantly lower free-energy barriers and faster nucleation rates than hard spheres. This difference primarily stems from localized orientational ordering, which steers polyhedral particles to pack more efficiently. Orientational order hence fosters here the growth of orientationally disordered nuclei.

Vikram Thapar; Fernando A. Escobedo

2013-11-11T23:59:59.000Z

358

The cloud condensation nuclei and ice nuclei effects on tropical anvil characteristics and water vapor of the tropical tropopause layer  

SciTech Connect

Cloud anvils from deep convective clouds are of great importance to the radiative energy budget and the aerosol impact on them is the least understood. Few studies examined the effects of both cloud condensation nuclei (CCN) and ice nuclei (IN) on anvil properties and water vapor content (WVC) in the Tropical Tropopause Layer (TTL). Using a 3-dimensional cloud-resolving model with size-resolved cloud microphysics, we focus on the CCN and IN effects on cloud anvil properties and WVC in the TTL. We find that cloud microphysical changes induced by CCN/IN play a very important role in determining cloud anvil area and WVC in the TTL, whether convection is enhanced or suppressed. Also, CCN effects on anvil microphysical properties, anvil size and lifetime are much more evident relative to IN. IN has little effect on convection, but can increase ice number and mass concentrations significantly under humid conditions. CCN in the PBL is found to have greater effects on convective strength and mid-tropospheric CCN has negligible effects on convection and cloud properties. Convective transport may only moisten the main convective outflow region but the cloud anvil size determines the WVC in the TTL domain. This study shows an important role of CCN in the lower-troposphere in modifying convection, the upper-level cloud properties. It also shows the effects of IN and the PBL CCN on the upper-level clouds depends on the humidity, resolving some contradictory results in past studies. 2

Fan, Jiwen; Comstock, Jennifer M.; Ovchinnikov, Mikhail

2010-11-10T23:59:59.000Z

359

Simultaneous multiparticle emissions in hot nuclei evaporation process  

SciTech Connect

This work presents a new mechanism for the evaporation with simultaneous particles emission mechanism in the evaporation chain as new channels opened to high excitation energy regime of the compound nucleus. The probability of multiple simultaneous emissions is determined based on phase space approach. A Monte Carlo simulation is employed to compute the final average yield of emitted particles after the decay chain. The neutron, proton, alpha and fission yields are obtained and compared to the conventional calculation with sequential simple particles emission and the relevance of the different channels in competition is also analyzed.

Santos, B. M. [Instituto de Fisica - Universidade Federal Fluminense Av. Gal. Milton Tavares de Souza, 24210-346 Niteroi. RJ (Brazil); De Assis, L. P.; Duarte, S. B. [Centro Brasileiro de Pesquisas Fisicas - CBPF Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro. RJ (Brazil)

2013-03-25T23:59:59.000Z

360

Experimental comparison of the active well coincidence counter with the random driver  

SciTech Connect

A direct comparison has been made between the IAEA Active Well Coincidence Counter (AWCC) and the LASL Random Driver at CMB-8. The comparison included an experimental evaluation of precision, counting rate, accuracy, penetrability, stability, and the effect of sample inhomogeneity. Samples used in the evaluation included highly enriched U/sub 3/O/sub 8/, U/sub 3/O/sub 8/ mixed with graphite, highly enriched uranium metal discs, and depleted uranium metal. These materials are typical of the samples of interest to the IAEA inspectors. It is concluded that the two instruments had very similar performance characteristics with the Random Driver giving better penetrability and the AWCC giving better stability.

Menlove, H.O.; Ensslin, N.; Sampson, T.E.

1979-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

Single-photon detection timing jitter in a visible light photon counter  

E-Print Network (OSTI)

Visible light photon counters (VLPCs) offer many attractive features as photon detectors, such as high quantum efficiency and photon number resolution. We report measurements of the single-photon timing jitter in a VLPC, a critical performance factor in a time-correlated single-photon counting measurement, in a fiber-coupled closed-cycle cryocooler. The measured timing jitter is 240 ps full-width-at-half-maximum at a wavelength of 550 nm, with a dark count rate of 25 000 counts per second. The timing jitter increases modestly at longer wavelengths to 300 ps at 1000 nm, and increases substantially at lower bias voltages as the quantum efficiency is reduced.

Burm Baek; Kyle S. McKay; Martin J. Stevens; Jungsang Kim; Henry H. Hogue; Sae Woo Nam

2009-11-30T23:59:59.000Z

362

Estimates of neutron reaction rates in three portable He-3 proportional counters  

SciTech Connect

The goal of this study is to obtain Monte Carlo estimates of neutron reaction rates for the {sup 3}He(n,p){sup 3}H reaction in two portable He-3 proportional counters in several configurations to quantify contributions from the environment, and optimize the tube characteristics. The smallest tube (0.5-inch diameter, 2-inch long, P = 10 atm) will not meet requirements. The largest tube (1-inch diameter, 4-inch long, P = 6 or 10 atm) will meet requirements and the tube length could be decreased to 2-inch at 6 atm and 1-inch at 10 atm. The 'medium' tube (3/4-inch diameter, 2-inch long, P = 10 atm) will meet requirements for the parallelepiped body, but will not for the cylindrical body.

Descalle, M; Labov, S

2007-03-01T23:59:59.000Z

363

Performance Considerations for Alternatives to 3He-Based Neutron Counters for Safeguards Applications  

Science Conference Proceedings (OSTI)

Worldwide, significant effort has been expended to develop replacement technologies for 3He-filled proportional counters used as neutron detectors and employed extensively in applications as diverse as Homeland Security portal monitoring to fundamental scientific research. Far less attention has been paid to the specific needs of safeguards measurement systems to meet mission objectives such as international obligations under the Nuclear Non-Proliferation Treaty. The measurement configuration, operational environments, and performance requirements for the typical safeguards assay system are sufficiently different from those of other applications that the new generation of neutron detectors is not generally suitable for use in demanding safeguards applications. To illustrate the performance needs for any viable replacement neutron detector technology, the operational constraints for several typical safeguards measurement systems are considered. Key attributes include achieving adequate efficiency per unit volume and minimal parasitic losses, along with gamma-ray immunity in a unit with high reliability and low maintenance.

McElroy, Robert Dennis [ORNL; Croft, Dr. Stephen [Los Alamos National Laboratory (LANL); Young, Brian M [Canberra Industries, Inc., Meriden, CT

2011-01-01T23:59:59.000Z

364

Shear flow driven drift waves and the counter-rotating vortices  

Science Conference Proceedings (OSTI)

It is shown that the drift waves can become unstable due to the shear flow produced by externally applied electric field. The modified Rayleigh instability condition is obtained which is applicable to both electron-ion and electron-positron-ion plasmas. It is proposed that the shear flow driven drift waves can be responsible for large amplitude electrostatic fluctuations in tokamak edges. In the nonlinear regime the stationary structures may appear in electron-positron-ion plasmas as well as electron-ion plasmas. A particular form of the shear flow can give rise to counter-rotating dipole vortices and vortex chains. The speed and amplitude of the structures are affected by the presence of positrons in the electron ion plasma. The relevance of this investigation to laboratory and astrophysical plasmas is pointed out.

Haque, Q.; Saleem, H.; Mirza, Arshad M. [Department of Physics, Commission on Science and Technology for Sustainable Development in the South (COMSATS) Institute of Information Technology, H-8 Islamabad, Pakistan and Pakistan Institute of Nuclear Science and Technology, PINSTECH (PRD), P.O. Nilore, Islamabad (Pakistan); Theoretical Plasma Physics Group, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

2005-10-01T23:59:59.000Z

365

Method and apparatus for removing coarse unentrained char particles from the second stage of a two-stage coal gasifier  

DOE Patents (OSTI)

A method and apparatus for removing oversized, unentrained char particles from a two-stage coal gasification process so as to prevent clogging or plugging of the communicating passage between the two gasification stages. In the first stage of the process, recycled process char passes upwardly while reacting with steam and oxygen to yield a first stage synthesis gas containing hydrogen and oxides of carbon. In the second stage, the synthesis gas passes upwardly with coal and steam which react to yield partially gasified char entrained in a second stage product gas containing methane, hydrogen, and oxides of carbon. Agglomerated char particles, which result from caking coal particles in the second stage and are too heavy to be entrained in the second stage product gas, are removed through an outlet in the bottom of the second stage, the particles being separated from smaller char particles by a counter-current of steam injected into the outlet.

Donath, Ernest E. (Christiansted, St. Croix, VI)

1976-01-01T23:59:59.000Z

366

Scintillation counter and wire chamber front end modules for high energy physics experiments  

SciTech Connect

This document describes two front-end modules developed for the proposed MIPP upgrade (P-960) experiment at Fermilab. The scintillation counter module was developed for the Plastic Ball detector time and charge measurements. The module has eight LEMO 00 input connectors terminated with 50 ohms and accepts negative photomultiplier signals in the range 0.25...1000 pC with the maximum input voltage of 4.0 V. Each input has a passive splitter with integration and differentiation times of {approx}20 ns. The integrated portion of the signal is digitized at 26.55 MHz by Analog Devices AD9229 12-bit pipelined 4-channel ADC. The differentiated signal is discriminated for time measurement and sent to one of the four TMC304 inputs. The 4-channel TMC304 chip allows high precision time measurement of rising and falling edges with {approx}100 ps resolution and has internal digital pipeline. The ADC data is also pipelined which allows deadtime-less operation with trigger decision times of {approx}4 {micro}s. The wire chamber module was developed for MIPP EMCal detector charge measurements. The 32-channel digitizer accepts differential analog signals from four 8-channel integrating wire amplifiers. The connection between wire amplifier and digitizer is provided via 26-wire twist-n-flat cable. The wire amplifier integrates input wire current and has sensitivity of 275 mV/pC and the noise level of {approx}0.013 pC. The digitizer uses the same 12-bit AD9229 ADC chip as the scintillator counter module. The wire amplifier has a built-in test pulser with a mask register to provide testing of the individual channels. Both modules are implemented as a 6Ux220 mm VME size board with 48-pin power connector. A custom europack (VME) 21-slot crate is developed for housing these front-end modules.

Baldin, Boris; DalMonte, Lou; /Fermilab

2011-01-01T23:59:59.000Z

367

Cluster aspects of p-shell and sd-shell nuclei  

SciTech Connect

We report some topics on cluster structures studied by using a theoretical method of antisymmetrized molecular dynamics(AMD). Cluster features of p-shell and sd-shell nuclei are discussed. In particular, three alpha cluster structures in the excited states of {sup 12}C and {sup 14}C are focused. Dineutron correlations in neutron-rich nuclei are also discussed.

Kanada-En'yo, Y.; Kobayashi, F.; Suhara, T. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Kimura, M. [Creative Research Initiative ''Sousei'', Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan); Taniguchi, Y. [RIKEN Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan)

2011-05-06T23:59:59.000Z

368

Role of BCS-type pairing in light deformed nuclei: A relativistic mean field approach  

E-Print Network (OSTI)

We calculate the binding energy and deformation parameter for light nuclei with and without pairing using a deformed relativistic mean field model. The role of BCS-type pairing effect is analyzed for Ne and F isotopes. The calculated odd-even staggering and the deformation parameters argue strongly against the role of pairing in the light nuclei.

P. Arumugam; T. K. Jha; S. K. Patra

2003-11-25T23:59:59.000Z

369

MOLECULAR GAS IN LUMINOUS GALACTIC NUCLEI N. Z. SCOVILLE AND A. J. BAKER  

E-Print Network (OSTI)

MOLECULAR GAS IN LUMINOUS GALACTIC NUCLEI N. Z. SCOVILLE AND A. J. BAKER California Institute­wave interferometry has clearly shown the existence of enormous masses (10 9 \\Gamma 10 10 M fi ) of molecular gas. In these systems, molecular gas is an obvious source of fuel for nuclear starbursts and active galactic nuclei (AGN

Baker, Andrew J.

370

Some Particle Properties  

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

Particle Properties Particle Properties An Article Written Originally for Midlevel Teachers Back A particle, increasing its speed because of some force acting on it, gains energy of motion. An electron (negatively charged) gains one electron volt (eV) of energy in accelerating through a vacuum from the negative end to the positive end of a one-volt battery. The one eV of energy is given up to other particles as the electron crashes into the positive end. A proton (positively charged) traveling from positive to negative pole through the vacuum would also gain one eV of energy and give it up in its collision with particles in the negative end. This proton collision is similar to the proton beam collision with a target at Fermilab, but at Fermilab the proton energy is much greater.

371

Imaging alpha particle detector  

DOE Patents (OSTI)

A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

Anderson, David F. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

372

HIGH ENERGY PARTICLE ACCELERATOR  

DOE Patents (OSTI)

An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.

Courant, E.D.; Livingston, M.S.; Snyder, H.S.

1959-04-14T23:59:59.000Z

373

Revisiting the symmetric reactions for synthesis of super heavy nuclei of $Z\\geq $120  

E-Print Network (OSTI)

Extensive efforts have been made experimentally to reach nuclei in the super heavy mass region of Z = 110 and above with suitable choices of projectile and target nuclei. The cross sections for production of these nuclei are seen to be in the range of a few picobarn or less, and pose great experimental challenges. Theoretically, there have been extensive calculations for highly asymmetric (hot-fusion) and moderately asymmetric (cold-fusion) collisions and only a few theoretical studies are available for near symmetric collisions to estimate the cross sections for production of super-heavy nuclei. In the present article, we revisit the symmetric heavy ion reactions with suitable combinations of projectile and target nuclei in the rare-earth region, that will lead to compound systems with very low excitation energy and with better neutron-to-proton ratio for higher stability.

R. K. Choudhury; Y. K. Gupta

2012-11-19T23:59:59.000Z

374

Are Globular Clusters the Remnant Nuclei of Progenitor Disk Galaxies?  

E-Print Network (OSTI)

The globular cluster system of a typical spheroidal galaxy makes up about 0.25% of the total galaxy mass (McLaughlin 1999). This is roughly the same mass fraction as contained in the nuclear star clus- ter (or stellar nucleus) present in most nearby low-mass galaxies. Motivated by this "coincidence", this Letter discusses a scenario in which globular clusters of present-day galaxies are the surviving nuclei of the dwarf galaxies that - according to the hierarchical merging paradigm of galaxy forma- tion - constitute the "building blocks" of present-day massive galaxies. This scenario, which was first suggested by Freeman (1993), has become more attractive recently in the light of studies that demonstrate a complex star formation history in a number of massive globular clusters.

Torsten Boeker

2007-11-28T23:59:59.000Z

375

Simple correlations between electric quadrupole moments of atomic nuclei  

SciTech Connect

Measurements of non-yrast electric quadrupole moments (i.e., diagonal E2 matrix elements) of atomic nuclei are becoming widely available from multiple-step Coulomb excitation. It is shown that, where quadrupole-moment data exist, $\\langle 2_1^+ ||E2|| 2_1^+ \\rangle+\\langle 2_2^+ ||E2|| 2_2^+ \\rangle\\approx 0$ is observed across a wide range of masses and deformations. In addition, $\\langle 4_1^+ ||E2|| 4_1^+ \\rangle+\\langle 4_2^+ ||E2|| 4_2^+ \\rangle+\\langle 4_3^+ ||E2|| 4_3^+ \\rangle\\approx 0$ is observed within two standard deviations for three of the four existing measurements. Rotor models appear to be sufficient in describing these trends.

Allmond, James M [ORNL] [ORNL

2013-01-01T23:59:59.000Z

376

Higher Nucleon Resonances in Exclusive $(?, ?N)$ Reactions on Nuclei  

E-Print Network (OSTI)

We report calculations for exclusive pion photoproduction on nuclei beyond the first resonance region in the distorted wave impulse approximation. The elementary operator contains contributions from the resonances $P_{33}(1232)$, $P_{11}(1440)$, $D_{13}(1520)$, $D_{33}(1740)$, $S_{11}(1535)$, $S_{11}(1650)$, and $F_{15}(1680)$, in addition to the usual Born plus vector meson contributions. It gives a good description of single pion photoproduction data up to about 1.1 GeV. Final state interactions are incorporated via optical potentials and are found to be substantial in the coincidence cross sections, but insensitive to the photon asymmetry. Clear signatures of possible medium modifications of the $D_{13}$ and $F_{15}$ resonances are predicted.

Frank X. Lee; C. Bennhold; S. S. Kamalov; L. E. Wright

1998-06-09T23:59:59.000Z

377

Atomic nuclei decay modes by spontaneous emission of heavy ions  

Science Conference Proceedings (OSTI)

The great majority of the known nuclides with Z>40, including the so-called stable nuclides, are metastable with respect to several modes of spontaneous superasymmetric splitting. A model extended from the fission theory of alpha decay allows one to estimate the lifetimes and the branching ratios relative to the alpha decay for these natural radioactivities. From a huge amount of systematic calculations it is concluded that the process should proceed with maximum intensity in the trans-lead nuclei, where the minimum lifetime is obtained from parent-emitted heavy ion combinations leading to a magic (/sup 208/Pb) or almost magic daughter nucleus. More than 140 nuclides with atomic number smaller than 25 are possible candidates to be emitted from heavy nuclei, with half-lives in the range of 10/sup 10/--10/sup 30/ s: /sup 5/He, /sup 8en-dash10/Be, /sup 11,12/B, /sup 12en-dash16/C, /sup 13en-dash17/N, /sup 15en-dash22/O, /sup 18en-dash23/F, /sup 20en-dash26/Ne, /sup 23en-dash28/Na, /sup 23en-dash30/Mg, /sup 27en-dash32/Al, /sup 28en-dash36/Si, /sup 31en-dash39/P, /sup 32en-dash42/S, /sup 35en-dash45/Cl, /sup 37en-dash47/Ar, /sup 40en-dash49/ K, . .Ca, /sup 44en-dash53/ Sc, /sup 46en-dash53/Ti, /sup 48en-dash54/V, and /sup 49en-dash55/ Cr. The shell structure and the pairing effects are clearly manifested in these new decay modes.

Poenaru, D.N.; Ivascu, M.; Sndulescu, A.; Greiner, W.

1985-08-01T23:59:59.000Z

378

From super-charged nuclei to massive nuclear density cores  

Science Conference Proceedings (OSTI)

Due to e{sup +}e{sup -}-pair production in the field of supercritical (Z>>Z{sub cr}{approx_equal}170) nucleus an electron shell, created out of the vacuum, is formed. The distribution of the vacuum charge in this shell has been determined for super-charged nuclei Z{sub e}{sup 3} > or approx. 1 within the framework of the Thomas-Fermi equation generalized to the relativistic case. For Z{sub e}{sup 3}>>1 the electron shell penetrates inside the nucleus and almost completely screens its charge. Inside such nucleus the potential takes a constant value equal to V{sub 0} = -(3{pi}{sup 2}n{sub p}){sup 1/3}approx-2m{sub {pi}}c{sup 2}, and super-charged nucleus represents an electrically neutral plasma consisting of e, p and n. Near the edge of the nucleus a transition layer exists with a width {lambda}{approx_equal}{alpha}{sup -1/2}h-bar/m{sub {pi}}c{approx}15 fm, which is independent of Z(h-bar/m{sub {pi}}celectric field and surface charge are concentrated in this layer. These results, obtained earlier for hypothetical superheavy nuclei with Z{approx}A/2 or approx. 0.04(Z/A){sup 1/2}(m{sub Planck}/m{sub n}){sup 3} the Coulomb repulsion of protons, screened by relativistic electrons, can be balanced by gravitational forces. The overcritical electric fields E{approx}m{sup 2}{sub {pi}}c{sup 3}/eh-bar are present in the narrow transition layer near the core surface.

Popov, Vladimir [Institute of Theoretical and Experimental Physics 117218 Moscow (Russian Federation)

2010-03-24T23:59:59.000Z

379

Measurement of highly enriched uranium metal buttons with the high-level neutron coincidence counter operating in the active mode  

SciTech Connect

The portable High-Level Neutron Coincidence Counter is used in the active mode with the addition of AmLi neutron sources to assay the /sup 235/U content of highly enriched metal pieces or buttons. It is concluded that the portable instrument is a practical instrument for assaying uranium metal buttons with masses in the range 1.5 to 4 kg.

Foley, J.E.

1980-10-01T23:59:59.000Z

380

Detecting Ice Nuclei with a Continuous—Flow Diffusion Chamber-Some Exploratory Tests of Instrument Response  

Science Conference Proceedings (OSTI)

A few basic experiments were performed with artificial cloud condensation nuclei and ice-nucleating aerosols in a continuous-flow thermal gradient diffusion chamber to investigate the instrument's response. Brief pulses of ice nuclei were input ...

David C. Rogers

1994-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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

Review of Particle Physics  

SciTech Connect

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, V{sub ud} and V{sub us}, V{sub cb} and V{sub ub}, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.

Particle Data Group; Nakamura, Kenzo; al., et

2010-06-30T23:59:59.000Z

382

Open Problems in $?$ Particle Condensation  

E-Print Network (OSTI)

$\\alpha$ particle condensation is a novel state in nuclear systems. We briefly review the present status on the study of $\\alpha$ particle condensation and address the open problems in this research field: $\\alpha$ particle condensation in heavier systems other than the Hoyle state, linear chain and $\\alpha$ particle rings, Hoyle-analogue states with extra neutrons, $\\alpha$ particle condensation related to astrophysics, etc.

Y. Funaki; M. Girod; H. Horiuchi; G. Roepke; P. Schuck; A. Tohsaki; T. Yamada

2010-03-05T23:59:59.000Z

383

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Fixed target experiments In a fixed-target experiment, a charged particle such as an electron or a...

384

The Particle Adventure | How do we experiment with tiny particles...  

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

experiment with tiny particles? - A linear or circular accelerator? All accelerators are either linear or circular, the difference being whether the particle is shot like a bullet...

385

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators and particle detectors - How do we experiment with tiny particles? - Major accelerators We invite you to explore the basic plans of the world's major accelerators so...

386

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerators Accelerators solve two problems for physicists. First, since all particles behave like waves, physicists use accelerators to increase a particle's momentum, thus...

387

The Particle Adventure  

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

Shortcomings Shortcomings of the first data Shortcomings of the first data The data were convincing but not perfect, and there were significant shortcomings. For one thing, by July 4, 2012, there weren't enough statistics to measure whether the rate at which this particle (the Higgs boson) decays to various collections of less massive particles (the "branching ratios") are those predicted by the Standard Model. A "branching ratio" is simply the probability that a particle will decay via a given decay channel. These ratios are predicted by the Standard Model, and measured by observing the same particle decay over and over again. The next plot shows the best measurements we can make of the branching ratios with the data available in 2013. Since these are the ratios to the

388

Heterogeneous particle swarm optimizers  

Science Conference Proceedings (OSTI)

Particle swarm optimization (PSO) is a swarm intelligence technique originally inspired by models of flocking and of social influence that assumed homogeneous individuals. During its evolution to become a practical optimization tool, some heterogeneous ...

Marco A. Montes De Oca; Jorge Peña; Thomas Stützle; Carlo Pinciroli; Marco Dorigo

2009-05-01T23:59:59.000Z

389

Particles and Prairies: Credits  

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

Particles and Prairies Video Sponsors: Funding for this program was provided in part by the U.S. Department of Energy Office of Energy Research, Illinois State Board of Education's...

390

Nuclear & Particle Physics Directorate  

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

Nuclear & Particle Physics Program Advisory Committee Meeting 21-22 June 2010 Agenda Submitted Proposals STAR Beam Use Proposal PHENIX Beam Use Proposal LoI: Feasibility Test of...

391

Nuclear & Particle Physics Directorate  

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

Draft Agenda Brookhaven Nuclear and Particle Physics Program Advisory Committee Meeting 6-8 June 2011 Reference Documents PAC Recommendations, 21-22 June 2010 Charge to PAC for...

392

The Particle Adventure | Glossary  

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

Collider A collider is an accelerator in which two beams traveling in opposite directions are steered together to provide high-energy collisions between the particles in one beam...

393

The Particle Adventure | Glossary  

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

Fixed-target Experiment An experiment in which the beam of particles from an accelerator is directed at a stationary (or nearly stationary) target. The target may be a solid, a...

394

The Particle Adventure  

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

How Do Fundamental Particles Get Mass? > How Does the Higgs Boson... How Does the Higgs Boson get its Mass? On the other hand, if a rumor crosses the room,... ...it creates the...

395

The Particle Adventure  

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

The Higgs Boson and Beyond > Is this Higgs Boson the Higgs Boson... Is this Higgs Boson the Higgs Boson of the Standard Model? We do know that the particle we discovered is a Higgs...

396

The Particle Adventure  

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

Boson Finding the Mass of the Higgs Boson How do you find the mass of the Higgs Boson when it decays into other particles before we detect it? If you were going to build a bicycle,...

397

Particle Data Group - Downloads  

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

2 web edition of RPP for different platforms 2012 book edition of RPP Particle Physics Booklet (rpp-2012-booklet.pdf file, 7 MBytes); Review of Partilce Physics 1526 pages, Phys....

398

Particle Data Group - Downloads  

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

1 web edition of RPP for different platforms 2010 book edition of RPP Particle Physics Booklet (rpp-2010-booklet.pdf file, 6 MBytes); rpp-2010-JPhys-G-37-075021.pdf file (40...

399

Particle Data Group  

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

2 book, booklet will be available in August. Web edition of the Review of Particle Physics is now available. Funded By: US DOE US NSF CERN MEXT (Japan) INFN (Italy) MEC (Spain)...

400

Particle Data Group - Downloads  

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

6 MBytes); rpp-2010-JPhys-G-37-075021.pdf file (40 MBytes) of the published RPP 2010 book; Figures from the reviews in RPP The PDG Monte Carlo particle numbering scheme The PDG...

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


401

Particle entrapping filamentry structures  

DOE Patents (OSTI)

Minute particulates are removed from a fluid flow by directing the fluid towards a particle entrapping element having a hair-like covering a flexible filaments. The filaments have fixed root ends and movable free ends that extend away from the roots and are shiftable in response to flow pressure and particle impacts. Particles lodge within the mass of filaments while the fluid component of the flow passes through particle entrapping element if the substrate is porous or is deflected away if the substrate is impervious. The structure does not necessarily cause a sizable pressure drop in the flow and can entrap large quantities of particulates. The invention has a variety of specific applications such as, for example, removal of smoke from the exhaust gases of vehicle engines or stationary fuel consuming installations. 11 figs.

Steele, W.A.; Leider, H.R.; Mohr, P.B.

1988-09-29T23:59:59.000Z

402

Particle Physics Experiment  

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

What Is A Particle Physics Experiment? The word "experiment" often makes people envision a scientist in white lab coat and goggles walking into the lab, pouring some test tubes...

403

Ice Nucleation and Droplet Formation by Bare and Coated Soot Particles  

Science Conference Proceedings (OSTI)

We have studied ice formation at temperatures relevant to homogeneous and heterogeneous ice nucleation, as well as droplet activation and hygroscopicity, of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span an atmospherically relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation, with a comparison to a mineral dust particle that acts as an efficient ice nucleus, and particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, only droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude that both uncoated and coated soot particles representative of those generated in our studies are unlikely to significantly contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

2011-09-13T23:59:59.000Z

404

Ice Nucleation and Droplet Formation by Bare and Coated Black Carbon Particles  

SciTech Connect

We have studied the ice formation at heterogeneous and homogeneous temperatures, as well as droplet activation and hygroscopicity of soot particles of variable size and composition. Coatings of adipic, malic, and oleic acid were applied to span a relevant range of solubility, and both uncoated and oleic acid coated soot particles were exposed to ozone to simulate atmospheric oxidation. The results are interpreted in terms of onset ice nucleation with a comparison to a well characterized mineral dust particle that acts as an efficient ice nucleus, as well as particle hygroscopicity. At 253K and 243K, we found no evidence of heterogeneous ice nucleation occurring above the level of detection for our experimental conditions. Above water saturation, droplet formation was observed. At 233K, we observe the occurrence of homogeneous ice nucleation for all particles studied. Coatings also did not significantly alter the ice nucleation behavior of soot particles, but aided in the uptake of water. Hygroscopicity studies confirmed that pure soot particles were hydrophobic, and coated soot particles activated as droplets at high water supersaturations. A small amount of heterogeneous ice nucleation either below the detection limit of our instrument or concurrent with droplet formation and/or homogeneous freezing cannot be precluded, but we are able to set limits for its frequency. We conclude from our studies that both uncoated and coated soot particles are unlikely to contribute to the global budget of heterogeneous ice nuclei at temperatures between 233K and 253K.

Friedman, Beth J.; Kulkarni, Gourihar R.; Beranek, Josef; Zelenyuk, Alla; Thornton, Joel A.; Cziczo, Daniel J.

2011-10-13T23:59:59.000Z

405

Future of superheavy element research: Which nuclei could be synthesized within the next few years?  

E-Print Network (OSTI)

Low values of the fusion cross sections and very short half-lives of nuclei with Z$>$120 put obstacles in synthesis of new elements. Different nuclear reactions (fusion of stable and radioactive nuclei, multi-nucleon transfers and neutron capture), which could be used for the production of new isotopes of superheavy (SH) elements, are discussed in the paper. The gap of unknown SH nuclei, located between the isotopes which were produced earlier in the cold and hot fusion reactions, can be filled in fusion reactions of $^{48}$Ca with available lighter isotopes of Pu, Am, and Cm. Cross sections for the production of these nuclei are predicted to be rather large, and the corresponding experiments can be easily performed at existing facilities. For the first time, a narrow pathway is found to the middle of the island of stability owing to possible $\\beta^+$-decay of SH isotopes which can be formed in ordinary fusion reactions of stable nuclei. Multi-nucleon transfer processes at near barrier collisions of heavy (and very heavy, U-like) ions are shown to be quite realistic reaction mechanism allowing us to produce new neutron enriched heavy nuclei located in the unexplored upper part of the nuclear map. Neutron capture reactions can be also used for the production of the long-living neutron rich SH nuclei. Strong neutron fluxes might be provided by pulsed nuclear reactors and by nuclear explosions in laboratory conditions and by supernova explosions in nature. All these possibilities are discussed in the paper.

Valeriy Zagrebaev; Alexander Karpov; Walter Greiner

2012-07-24T23:59:59.000Z

406

Mechanism of production of light complex particles in nucleon-induced reactions  

E-Print Network (OSTI)

The Improved Quantum Molecular Dynamics (ImQMD) model incorporated with the statistical decay model is successful in describing emission of nucleons in the intermediate energy spallation reactions, but not good enough in describing productions of light complex particles, i.e. $d$, $t$, $^3$He and $^4$He. To improve the description on emission of light complex particles, a phenomenological mechanism called surface coalescence and emission is introduced into ImQMD model: nucleon ready to escape from the compound nuclei can coalesce with the other nucleon(s) to form light complex particle and be emitted. With updated ImQMD model, the great improvements are achieved. The experimental data of light complex particles in nucleon-induced reactions with energies from 62 to 1200 MeV on various targets are reproduced quite well.

Dexian Wei; Ning Wang; Li Ou

2013-09-29T23:59:59.000Z

407

GPU COMPUTING FOR PARTICLE TRACKING  

E-Print Network (OSTI)

a simple GPU based particle tracking code, TracyGPU, isP U COMPUTING FOR PARTICLE TRACKING Hiroshi Nishimura, K a iCOMPUTING FOR PARTICLE TRACKING * Hiroshi Nishimura ', Kai

Nishimura, Hiroshi

2011-01-01T23:59:59.000Z

408

ENSEMBLE VARIABILITY OF NEAR-INFRARED-SELECTED ACTIVE GALACTIC NUCLEI  

Science Conference Proceedings (OSTI)

We present the properties of the ensemble variability V for nearly 5000 near-infrared active galactic nuclei (AGNs) selected from the catalog of Quasars and Active Galactic Nuclei (13th Edition) and the SDSS-DR7 quasar catalog. From three near-infrared point source catalogs, namely, Two Micron All Sky Survey (2MASS), Deep Near Infrared Survey (DENIS), and UKIDSS/LAS catalogs, we extract 2MASS-DENIS and 2MASS-UKIDSS counterparts for cataloged AGNs by cross-identification between catalogs. We further select variable AGNs based on an optimal criterion for selecting the variable sources. The sample objects are divided into subsets according to whether near-infrared light originates by optical emission or by near-infrared emission in the rest frame; and we examine the correlations of the ensemble variability with the rest-frame wavelength, redshift, luminosity, and rest-frame time lag. In addition, we also examine the correlations of variability amplitude with optical variability, radio intensity, and radio-to-optical flux ratio. The rest-frame optical variability of our samples shows negative correlations with luminosity and positive correlations with rest-frame time lag (i.e., the structure function, SF), and this result is consistent with previous analyses. However, no well-known negative correlation exists between the rest-frame wavelength and optical variability. This inconsistency might be due to a biased sampling of high-redshift AGNs. Near-infrared variability in the rest frame is anticorrelated with the rest-frame wavelength, which is consistent with previous suggestions. However, correlations of near-infrared variability with luminosity and rest-frame time lag are the opposite of these correlations of the optical variability; that is, the near-infrared variability is positively correlated with luminosity but negatively correlated with the rest-frame time lag. Because these trends are qualitatively consistent with the properties of radio-loud quasars reported by some previous studies, most of our sample objects are probably radio-loud quasars. Finally, we also discuss the negative correlations seen in the near-infrared SFs.

Kouzuma, S. [School of International Liberal Studies, Chukyo University, Toyota 470-0393 (Japan); Yamaoka, H., E-mail: skouzuma@lets.chukyo-u.ac.jp, E-mail: yamaoka@phys.kyushu-u.ac.jp [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)

2012-03-01T23:59:59.000Z

409

Equation of state for finite nuclei and liquid-gas phase transition  

E-Print Network (OSTI)

We construct the equation of state (EOS) of finite nuclei including surface and Coulomb effects in a Thomas-Fermi framework using a finite range, momentum and density dependent two-body interaction. We identify critical temperatures for nuclei below which the EOS so constructed shows clear signals for liquid-gas phase transition in these finite systems. Comparison with the EOS of infinite nuclear matter shows that the critical density and temperature of the phase transition in nuclei are influenced by the mentioned finite size effects.

J. N. De; B. K. Agrawal; S. K. Samaddar

1998-11-27T23:59:59.000Z

410

Competition between alpha-decay and beta-decay for Heavy and Superheavy Nuclei  

E-Print Network (OSTI)

In this work, the $\\beta$-stable region for Z $\\geq$ 90 is proposed. The calculated $\\beta$-stable nuclei in the $\\beta$-stable region are in good agreement with the ones obtained by M\\"{o}ller \\emph{et al}.. The half-lives of the nuclei close to the $\\beta$-stable region are calculated and the competition between $\\alpha$-decay and $\\beta$-decay is systematically investigated. The calculated half-lives and the suggested decay modes are well in line with the experimental results. The predictions for half-lives and decay modes of the nuclei with Z = 107$-$110 are presented.

Zongqiang Sheng; Liangping Shu; Ying Meng; Jigang Hu; Jianfa Qian

2014-01-16T23:59:59.000Z

411

Physics Out Loud - Elementary Particles  

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

Electrons Previous Video (Electrons) Physics Out Loud Main Index Next Video (Gluons) Gluons Elementary Particles Learn about elementary particles from Jo Dudek, a jointly appointed...

412

Online Particle Physics Information - Scope  

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

SLAC Online Particle Physics Information PDG Scope of this Guide While a substantial amount of particle physics information is Internet accessible, most listings do not provide...

413

System for forming janus particles  

DOE Patents (OSTI)

The invention is a method of forming Janus particles, that includes forming an emulsion that contains initial particles, a first liquid, and a second liquid; solidifying the first liquid to form a solid that contains at least a portion of the initial particles on a surface of the solid; and treating the exposed particle sides with a first surface modifying agent, to form the Janus particles. Each of the initial particles on the surface has an exposed particle side and a blocked particle side.

Hong, Liang (Midland, MI); Jiang, Shan (Champaign, IL); Granick, Steve (Champaign, IL)

2011-01-25T23:59:59.000Z

414

Marine Fog Droplets and Salt Nuclei -Part 11  

Science Conference Proceedings (OSTI)

In Past 1 of this fog study, the distribution of water with number and size of drops in some New England marine advection fogs was shown to be related to the distribution of number and size of salt particles found in marine air. It was indicated ...

Alfred H. Woodcock; Duncan C. Blanchard; James E. Jiusto

1981-01-01T23:59:59.000Z

415

Iterated and irreducible pion-photon exchange in nuclei  

E-Print Network (OSTI)

We calculate the contribution to the nuclear energy density functional which arises from iterated pion-photon exchange between nucleons. In heavy nuclei, this novel charge symmetry breaking interaction leads to an additional binding of each proton by about 0.2 MeV. Compared to that the analogous effect from irreducible pion-photon exchange is negligibly small. As a possible mechanism to resolve the Nolen-Schiffer anomaly we propose the iteration of one-photon exchange with an attractive short-range NN-interaction. The corresponding energy per proton reads: $\\bar E[\\rho_p]=(2\\alpha/15\\pi^2)(\\pi^2 -3+6 \\ln2) {\\cal A}_{pp} k_p^2$ with $\\rho_p =k_p^3/ 3\\pi^2$ the proton density and ${\\cal A}_{pp}\\approx 2 $fm an effective (in-medium) scattering length. Hints for such a value of ${\\cal A}_{pp}$ come from phenomenological Skyrme forces and from the neutron matter equation of state.

N. Kaiser

2003-12-16T23:59:59.000Z

416

Laser Probing of Neutron-Rich Nuclei in Light Atoms  

E-Print Network (OSTI)

The neutron-rich 6He and 8He isotopes exhibit an exotic nuclear structure that consists of a tightly bound 4He-like core with additional neutrons orbiting at a relatively large distance, forming a halo. Recent experimental efforts have succeeded in laser trapping and cooling these short-lived, rare helium atoms, and have measured the atomic isotope shifts along the 4He-6He-8He chain by performing laser spectroscopy on individual trapped atoms. Meanwhile, the few-electron atomic structure theory, including relativistic and QED corrections, has reached a comparable degree of accuracy in the calculation of the isotope shifts. In parallel efforts, also by measuring atomic isotope shifts, the nuclear charge radii of lithium and beryllium isotopes have been studied. The techniques employed were resonance ionization spectroscopy on neutral, thermal lithium atoms and collinear laser spectroscopy on beryllium ions. Combining advances in both atomic theory and laser spectroscopy, the charge radii of these light halo nuclei have now been determined for the first time independent of nuclear structure models. The results are compared with the values predicted by a number of nuclear structure calculations, and are used to guide our understanding of the nuclear forces in the extremely neutron-rich environment.

Z. -T. Lu; P. Mueller; G. W. F. Drake; W. Noertershaeuser; Steven C. Pieper; Z. -C. Yan

2013-07-10T23:59:59.000Z

417

The Coincidence of Nuclear Star Clusters and Active Galactic Nuclei  

E-Print Network (OSTI)

We study galaxies that host both nuclear star clusters and active galactic nuclei (AGN) implying the presence of a massive black hole. We select a sample of 176 galaxies with previously detected nuclear star clusters that range from ellipticals to late-type spirals. We search for AGN in this sample using optical spectroscopy and archival radio and X-ray data. We find galaxies of all Hubble types and with a wide range of masses (10^9-11 solar masses) hosting both AGN and nuclear star clusters. From the optical spectra, we classify 10% of the galaxies as AGN and an additional 15% as composite, indicating a mix of AGN and star-formation spectra. The fraction of nucleated galaxies with AGN increases strongly as a function of galaxy and nuclear star cluster mass. For galaxies with both a NC and a black hole, we find that the masses of these two objects are quite similar. However, non-detections of black holes in Local Group nuclear star clusters show that not all clusters host black holes of similar masses. We discuss the implications of our results for the formation of nuclear star clusters and massive black holes.

Anil Seth; Marcel Agueros; Duane Lee; Antara Basu-Zych

2008-01-02T23:59:59.000Z

418

Neutrino-induced pion production from nuclei at medium energies  

E-Print Network (OSTI)

We present a fully relativistic formalism for describing neutrino-induced $\\Delta$-mediated single-pion production from nuclei. We assess the ambiguities stemming from the $\\Delta$ interactions. Variations in the cross sections of over 10% are observed, depending on whether or not magnetic-dipole dominance is assumed to extract the vector form factors. These uncertainties have a direct impact on the accuracy with which the axial-vector form factors can be extracted. Different predictions for $C_5^A(Q^2)$ induce up to 40-50% effects on the $\\Delta$-production cross sections. To describe the nucleus, we turn to a relativistic plane-wave impulse approximation (RPWIA) using realistic bound-state wave functions derived in the Hartree approximation to the $\\sigma$-$\\omega$ Walecka model. For neutrino energies larger than 1 GeV, we show that a relativistic Fermi-gas model with appropriate binding-energy correction produces comparable results as the RPWIA which naturally includes Fermi motion, nuclear-binding effects and the Pauli exclusion principle. Including $\\Delta$ medium modifications yields a 20 to 25% reduction of the RPWIA cross section. The model presented in this work can be naturally extended to include the effect of final-state interactions in a relativistic and quantum-mechanical way. Guided by recent neutrino-oscillation experiments, such as MiniBooNE and K2K, and future efforts like MINER$\

C. Praet; O. Lalakulich; N. Jachowicz; J. Ryckebusch

2008-04-17T23:59:59.000Z

419

Time-of-Flight Mass Measurements of Exotic Nuclei  

Science Conference Proceedings (OSTI)

Atomic masses play an important role in nuclear physics and astrophysics. The need of experimental mass values for unstable nuclides has triggered the development of a wide range of mass measurement techniques, with devices installed at many laboratories around the world. We have implemented a time-of-flight magnetic-rigidity (TOF-B ) technique at the National Superconducting Cyclotron Laboratory (NSCL) that includes a position measurement for magnetic rigidity corrections and uses the A1900 separator and the S800 spectrograph. We performed a successful first experiment measuring masses of neutron-rich isotopes in the region of Z 20 30, important for calculations of processes occurring in the crust of accreting neutron stars. The masses of 16 nuclei were determined, for 61V, 63Cr, 66Mn, and 74Ni for the first time, with atomic mass excesses of 30.510(890) MeV, 35.280(650) MeV, 36.900(790) MeV, and 49.210(990) MeV, respectively. The mass resolution achieved was 1.8 10 4.

Matos, M. [Michigan State Univ./JINA/Louisiana State University; Estrade, A. [Michigan State Univ./JINA/LSU/Saint Mary's Univ./GSI Darmstadt, GE; Schatz, H. [Michigan State Univ./JINA; Bazin, D. [Michigan State University, East Lansing; Famiano, M. [Western Michigan University, Kalamazoo; Gade, A. [Michigan State University, East Lansing; George, S. [NSCL, Michigan State University, East Lansing; Lynch, W. G. [NSCL, Michigan State Univ./JINA; Meisel, Z. [NSCL, Michigan State Univ./JINA; Portillo, M. [NSCL, Michigan State University, East Lansing; Rogers, A. [NSCL, Michigan State Univ./JINA; Shapira, Dan [ORNL; Stolz, A. [Michigan State University, East Lansing; Wallace, M. [Los Alamos National Laboratory (LANL); Yurkon, J. [NSCL, Michigan State University, East Lansing

2012-01-01T23:59:59.000Z

420

Cloud Condensation Nuclei Profile Value-Added Product  

SciTech Connect

The cloud condensation nuclei (CCN) concentration at cloud base is the most relevant measure of the aerosol that influences droplet formation in clouds. Since the CCN concentration depends on supersaturation, a more general measure of the CCN concentration is the CCN spectrum (values at multiple supersaturations). The CCN spectrum is now measured at the surface at several fixed ARM sites and by the ARM Mobile Facility (AMF), but is not measured at the cloud base. Rather than rely on expensive aircraft measurements for all studies of aerosol effects on clouds, a way to project CCN measurements at the surface to cloud base is needed. Remote sensing of aerosol extinction provides information about the vertical profile of the aerosol, but cannot be directly related to the CCN concentration because the aerosol extinction is strongly influenced by humidification, particularly near cloud base. Ghan and Collins (2004) and Ghan et al. (2006) propose a method to remove the influence of humidification from the extinction profiles and tie the “dry extinction” retrieval to the surface CCN concentration, thus estimating the CCN profile. This methodology has been implemented as the CCN Profile (CCNPROF) value-added product (VAP).

McFarlane, S; Sivaraman, C; Ghan, S

2012-10-08T23:59:59.000Z

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


421

Quasifree Pion Electroproduction from Nuclei in the $?$ Region  

E-Print Network (OSTI)

We present calculations of the reaction $A(e,e^\\prime \\pi N)B$ in the distorted wave impulse approximation. The reaction allows for the study of the production process in the nuclear medium without being obscured by the details of nuclear transition densities. First, a pion electroproduction operator suitable for nuclear calculations is obtained by extending the Blomqvist-Laget photoproduction operator to the virtual photon case. The operator is gauge invariant, unitary, reference frame independent, and describes the existing data reasonably well. Then it is applied in nuclei to predict nuclear cross sections under a variety of kinematic arrangements. Issues such as the effects of gauge-fixing, the interference of the $\\Delta$ resonance with the background, sensitivities to the quadrupole component of the $\\Delta$ excitation and to the electromagnetic form factors, the role of final-state interactions, are studied in detail. Methods on how to experimentally separate the various pieces in the coincidence cross section are suggested. Finally, the model is compared to a recent SLAC experiment.

F. X. Lee; L. E. Wright; C. Bennhold

1995-10-27T23:59:59.000Z

422

Particles in the Lower Troposphere over the High Plains of the United States. Part III: Ice Nuclei  

Science Conference Proceedings (OSTI)

One hundred and fifty-five ice nucleus (IN) spectra were measured from an aircraft at various locations over the High Plains of the United States during the springs and summers of 1975 and 1976. Frequency distributions of the IN concentrations at ...

David A. Bowdle; Peter V. Hobbs; Lawrence F. Radke

1985-12-01T23:59:59.000Z

423

RESONATOR PARTICLE SEPARATOR  

DOE Patents (OSTI)

A wave guide resonator structure is described for use in separating particles of equal momentum but differing in mass and having energies exceeding one billion electron volts. The particles are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high-energy accelerator. In this wave guide construction, the particles undergo preferential deflection as a result of the presence of an electric field. The boundary conditions established in the resonator are such as to eliminate an interfering magnetic component, and to otherwise phase the electric field to obtain a traveling wave such as one which moves at the same speed as the unwanted particle. The latter undergoes continuous deflection over the whole length of the device and is, therefore, eliminated while the wanted particle is deflected in opposite directions over the length of the resonator and is thus able to enter an exit aperture. (AEC)

Blewett, J.P.

1962-01-01T23:59:59.000Z

424

Chemical Characterization of Individual Particles and Residuals of Cloud Droplets and Ice Crystals Collected On Board Research Aircraft in the ISDAC 2008 Study  

Science Conference Proceedings (OSTI)

Although it has been shown that size of atmospheric particles has a direct correlation with their ability to act as cloud droplet and ice nuclei, the influence of composition of freshly emitted and aged particles in nucleation processes is poorly understood. In this work we combine data from field measurements of ice nucleation with chemical imaging of the sampled particles to link aerosol composition with ice nucleation ability. Field measurements and sampling were conducted during the Indirect and Semidirect Aerosols Campaign (ISDAC) over Barrow, Alaska, in the springtime of 2008. In-situ ice nucleation measurements were conducted using a Continuous Flow Diffusion Chamber (CFDC). Measured number concentrations of ice nuclei (IN) varied from frequent values of 0.01 per liter to more than 10 per liter. Residuals of airborne droplets and ice crystals were collected through a counterflow virtual impactor (CVI). The compositions of individual atmospheric particles and the residuals were studied using Computer Controlled Scanning Electron Microscopy with Energy Dispersive X-ray analysis (CCSEM/EDX) and Scanning Transmission X-ray Microscopy coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (STXM/NEXAFS). Chemical analysis of cloud particle residuals collected during an episode of high ice nucleation suggests that both size and composition may influence aerosol's ability to act as IN. The STXM/NEXAFS chemical composition maps of individual residuals have characteristic structures of either inorganic or black carbon cores coated by organic materials. In a separate flight, particle samples from a biomass burning plume were collected. Although it has previously been suggested that episodes of biomass burning contribute to increased numbers of highly effective ice nuclei, in this episode we observed that only a small fraction were effective ice nuclei. Most of the particles from the biomass plume episode were smaller in size and were composed of homogeneous organic material without identifiable cores.

Hiranuma, Naruki; Brooks, Sarah D.; Moffet, Ryan C.; Glen, Andrew; Laskin, Alexander; Gilles, Marry K.; Liu, Peter; MacDonald, A. M.; Strapp, J. Walter; McFarquhar, Greg

2013-06-24T23:59:59.000Z

425

Structural Evolution in Atomic Nuclei: Residual Interactions, Quantum Phase Transitions and the Emergence of Collectivity  

Science Conference Proceedings (OSTI)

A synoptic view of the evolution of structure with Z and N in nuclei is beginning to emerge from the confiuence of new experimental results on phase transitional behavior, newly proposed many-body symmetries for critical point nuclei, a new generation of solvable collective models, powerful approaches to viewing the systematics of nuclear properties based on simple models of residual interactions, and advances in microscopic calculations of medium mass and heavy nuclei. A recent compilation of nuclear masses has contributed by permitting empirical extractions of new p-n interaction strengths of the last protons with the last neutrons in many nuclei across the nuclear chart. A number of these developments will be discussed with an eye to the opportunities and challenges they provide for the future, especially in the era of next-generation exotic beam facihties throughout the world.

Casten, R. F. [A.W. Wright Nuclear Structure Laboratory, Yale University, New Haven, CT (United States)

2007-10-26T23:59:59.000Z

426

Fission of actinides and superheavy nuclei: covariant density functional theory perspective  

E-Print Network (OSTI)

The current status of the application of covariant density functional theory to the description of fission barriers in actinides and superheavy nuclei is reviewed. The achievements and open problems are discussed.

A. V. Afanasjev

2013-03-05T23:59:59.000Z

427

Investigation of the Variability of Cloud Condensation Nuclei Concentrations at the Surface in Western North Dakota  

Science Conference Proceedings (OSTI)

Daily observations of cloud condensation nuclei (CCN) were made for three summer months in 2005 at a site in rural western North Dakota. The goal was to define the natural background CCN population characteristics and to lay the groundwork for ...

Andrew Detwiler; Darin Langerud; Tracy Depue

2010-01-01T23:59:59.000Z

428

Biogenic and Anthropogenic Sources of Ice-Forming Nuclei: A Review  

Science Conference Proceedings (OSTI)

To develop theories and numerical models of the formation and microstructure of clouds and precipitation, it is necessary to identify the potential sources of ice nuclei in the atmosphere. However, the subject remains an area of debate. According ...

Wanda Szyrmer; Isztar Zawadzki

1997-02-01T23:59:59.000Z

429

Fine Particles in Soils  

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

Fine Particles in Soils Fine Particles in Soils Nature Bulletin No. 582 November 28, 1959 Forest Preserve District of Cook County Daniel Ryan, President Roberts Mann, Conservation Editor David H. Thompson, Senior Naturalist FINE PARTICLES IN SOILS If a farmer, while plowing, is visited in the field by another farmer, invariably the visitor will pick up a handful of turned over earth and knead it with his fingers while they talk. The "feel" of it tells him a lot about the texture and structure of that soil. He knows that both are important factors in the growth of plants and determine the crops that may be obtained from the land. Soil is a combination of three different things About half of it is solid matter; the other half consists of air and water The solid portion is composed of organic and inorganic materials.

430

Carbon-particle generator  

DOE Patents (OSTI)

A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

Hunt, A.J.

1982-09-29T23:59:59.000Z

431

Charged particle accelerator grating  

DOE Patents (OSTI)

A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

Palmer, R.B.

1985-09-09T23:59:59.000Z

432

Precision wood particle feedstocks  

DOE Patents (OSTI)

Wood particles having fibers aligned in a grain, wherein: the wood particles are characterized by a length dimension (L) aligned substantially parallel to the grain, a width dimension (W) normal to L and aligned cross grain, and a height dimension (H) normal to W and L; the L.times.H dimensions define two side surfaces characterized by substantially intact longitudinally arrayed fibers; the W.times.H dimensions define two cross-grain end surfaces characterized individually as aligned either normal to the grain or oblique to the grain; the L.times.W dimensions define two substantially parallel top and bottom surfaces; and, a majority of the W.times.H surfaces in the mixture of wood particles have end checking.

Dooley, James H; Lanning, David N

2013-07-30T23:59:59.000Z

433

Manual for the Portable Handheld Neutron Counter (PHNC) for Neutron Survey and the Measurement of Plutonium Samples  

SciTech Connect

We have designed a portable neutron detector for passive neutron scanning measurement and coincidence counting of bulk samples of plutonium. The counter will be used for neutron survey applications as well as the measurement of plutonium samples for portable applications. The detector uses advanced design {sup 3}He tubes to increase the efficiency and battery operated shift register electronics. This report describes the hardware, performance, and calibration for the system.

H.O. Menlove

2005-11-01T23:59:59.000Z

434

Single Particle Laser Mass Spectrometry Applied to Differential Ice Nucleation Experiments at the AIDA Chamber  

SciTech Connect

Experiments conducted at the Aerosol Interactions and Dynamics in the Atmosphere (AIDA) chamber located in Karlsruhe, Germany permit investigation of particle properties that affect the nucleation of ice at temperature and water vapor conditions relevant to cloud microphysics and climate issues. Ice clouds were generated by heterogeneous nucleation of Arizona test dust (ATD), illite, and hematite and homogeneous nucleation of sulfuric acid. Ice crystals formed in the chamber were inertially separated from unactivated, or ‘interstitial’ aerosol particles with a pumped counterflow virtual impactor (PCVI), then evaporated. The ice residue (i.e., the aerosol which initiated ice nucleation plus any material which was scavenged from the gas- and/or particle-phase), was chemically characterized at the single particle level using a laser ionization mass spectrometer. In this manner the species that first nucleated ice could be identified out of a mixed aerosol population in the chamber. Bare mineral dust particles were more effective ice nuclei (IN) than similar particles with a coating. Metallic particles from contamination in the chamber initiated ice nucleation before other species but there were few enough that they did not compromise the experiments. Nitrate, sulfate, and organics were often detected on particles and ice residue, evidently from scavenging of trace gas-phase species in the chamber. Hematite was a more effective ice nucleus than illite. Ice residue was frequently larger than unactivated test aerosol due to the formation of aggregates due to scavenging, condensation of contaminant gases, and the predominance of larger aerosol in nucleation.

Gallavardin, S. J.; Froyd, Karl D.; Lohmann, U.; Moehler, Ottmar; Murphy, Daniel M.; Cziczo, Dan

2008-08-26T23:59:59.000Z

435

Synthesis of transactinide nuclei in cold fusion reactions using radioative beams  

E-Print Network (OSTI)

Chances of synthesis of transactinide nuclei in cold fusion reactions (one-neutron-out) reactions using radioactive beams are evaluated. Because intensities of radioactive beams are in most of the cases significantly lower than the ones of the stable beams, reactions with the highest radioactive beam intensities for the particular elements are considered. The results are compared with the recent ones obtained by Loveland who investigated the same nuclei.

Smolanczuk, Robert

2009-01-01T23:59:59.000Z

436

Synthesis of transactinide nuclei in cold fusion reactions using radioative beams  

E-Print Network (OSTI)

Chances of synthesis of transactinide nuclei in cold fusion reactions (one-neutron-out) reactions using radioactive beams are evaluated. Because intensities of radioactive beams are in most of the cases significantly lower than the ones of the stable beams, reactions with the highest radioactive beam intensities for the particular elements are considered. The results are compared with the recent ones obtained by Loveland who investigated the same nuclei.

Robert Smolanczuk

2009-12-04T23:59:59.000Z

437

Synthesis of transactinide nuclei in cold fusion reactions using radioactive beams  

SciTech Connect

Chances of synthesis of transactinide nuclei in cold fusion reactions (one-neutron-out reactions) using radioactive beams are evaluated. Because in most of the cases intensities of radioactive beams are significantly less than those of the stable beams, reactions with the greatest radioactive-beam intensities for the particular elements are considered. The results are compared with the recent ones obtained by Loveland [Phys. Rev. C 76, 014612 (2007)], who investigated the same nuclei.

Smolanczuk, Robert [Theoretical Physics Department, Soltan Institute for Nuclear Studies, Hoza 69, PL-00-681 Warszawa (Poland)

2010-06-15T23:59:59.000Z

438

Correlations between signals of the liquid-gas phase transition in nuclei  

E-Print Network (OSTI)

Finite systems such as atomic nuclei present at phase transition specific features different from those observed at the thermodynamic limit. Several characteristic signals were found in samples of events resulting from heavy ion collisions at and above the Fermi energy. The concomitant observation of different signatures of a liquid-gas phase transition in nuclei on a given sample strongly supports the occurrence of this transition.

Marie-France Rivet; N. Le Neindre; J. P. Wieleczko; B. Borderie; R. Bougault; A. Chbihi; J. D. Frankland; M. Parlog; M. Pichon; B. Tamain; the INDRA; ALADIN Collaboration

2004-12-06T23:59:59.000Z

439

Beyond the No Core Shell Model: Extending the NCSM to Heavier Nuclei  

Science Conference Proceedings (OSTI)

The No Core Shell Model (NCSM) is an ab initio method for calculating the properties of light nuclei, up to about A = 20, in which all A nucleons are treated as being active. It is difficult to go to larger A values due to the rapid grow of the basis spaces required in order to obtain converged results. In this presentation we briefly discuss three new techniques for extending the NCSM to heavier mass nuclei.

Barrett, Bruce R. [Department of Physics, P.O. Box 210081, University of Arizona, Tucson, AZ 85721-0081 (United States)

2011-05-06T23:59:59.000Z

440

HARD X-RAYEMITTING ACTIVE GALACTIC NUCLEI SELECTED BY THE CHANDRA MULTIWAVELENGTH PROJECT  

E-Print Network (OSTI)

HARD X-RAY­EMITTING ACTIVE GALACTIC NUCLEI SELECTED BY THE CHANDRA MULTIWAVELENGTH PROJECT J. D present X-ray and optical analysis of 188 active galactic nuclei (AGN) identified from 497 hard X-ray ( f2:0 8:0 keV > 2:7 ; 10�15 ergs cm�2 s�1 ) sources in 20 Chandra fields (1.5 deg2 ) forming part

Green, Paul

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


441

Fusion cross sections for superheavy nuclei in the dinuclear system concept  

E-Print Network (OSTI)

Using the dinuclear system concept we present calculations of production cross sections for the heaviest nuclei. The obtained results are in a good agreement with the experimental data. The experimentally observed rapid fall-off of the cross sections of the cold fusion with increasing charge number $Z$ of the compound nucleus is explained. Optimal experimental conditions for the synthesis of the superheavy nuclei are suggested.

G. G. Adamian; N. V. Antonenko; W. Scheid; V. V. Volkov

1997-10-18T23:59:59.000Z

442

A Stable Massive Charged Particle  

E-Print Network (OSTI)

We consider the possibility of the existence of a stable massive charged particle by a minimal extension of the standard model particle content. Absolute stability in the case of singly charged particle is not possible if the usual doublet Higgs exists, unless a discrete symmetry is imposed.But a doubly charged particle is absolutely stable.

G. Rajasekaran

2011-05-26T23:59:59.000Z

443

Evaluation of Counter-Based Dynamic Load Balancing Schemes for Massive Contingency Analysis on Over 10,000 Cores  

SciTech Connect

Contingency analysis studies are necessary to assess the impact of possible power system component failures. The results of the contingency analysis are used to ensure the grid reliability, and in power market operation for the feasibility test of market solutions. Currently, these studies are performed in real time based on the current operating conditions of the grid with a set of pre-selected contingency list, which might result in overlooking some critical contingencies caused by variable system status. To have a complete picture of a power grid, more contingencies need to be studied to improve grid reliability. High-performance computing techniques hold the promise of being able to perform the analysis for more contingency cases within a much shorter time frame. This paper evaluates the performance of counter-based dynamic load balancing schemes for a massive contingency analysis program on 10,000+ cores. One million N-2 contingency analysis cases with a Western Electricity Coordinating Council power grid model have been used to demonstrate the performance. The speedup of 3964 with 4096 cores and 7877 with 10240 cores are obtained. This paper reports the performance of the load balancing scheme with a single counter and two counters, describes disk I/O issues, and discusses other potential techniques for further improving the performance.

Chen, Yousu; Huang, Zhenyu; Rice, Mark J.

2012-12-27T23:59:59.000Z

444

Apparatus for measuring particle properties  

DOE Patents (OSTI)

An apparatus for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle's size can be determined from the intensity of the light scattered. The particle's velocity can be determined from the elapsed time between various intensities of the light scattered.

Rader, Daniel J. (Albuquerque, NM); Castaneda, Jaime N. (Albuquerque, NM); Grasser, Thomas W. (Albuquerque, NM); Brockmann, John E. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

445

Heterogeneous ice nucleation and water uptake by field-collected atmospheric particles below 273 K  

Science Conference Proceedings (OSTI)

Atmospheric ice formation induced by particles with complex chemical and physical properties through heterogeneous nucleation is not well understood. Heterogeneous ice nucleation and water uptake by ambient particles collected from urban environments in Los Angeles and Mexico City are presented. Using a vapour controlled cooling system equipped with an optical microscopy, the range of onset conditions for ice nucleation and water uptake by the collected particles was determined as a function of temperature (200{273 K) and relative humidity with respect to ice (RHice) up to water saturation. Three distinctly different types of authentic atmospheric particles were investigated including soot particles associated with organics/inorganics, inorganic particles of marine origin coated with organic material, and Pb/Zn containing inorganic particles apportioned to anthropogenic emissions relevant to waste incineration. Single particle characterization was provided by micro-spectroscopic analyses using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption ne structure spectroscopy (STXM/NEXAFS). Above 230 K, signicant differences in water uptake and immersion freezing effciencies of the different particle types were observed. Below 230 K, the particles exhibited high deposition ice nucleation effciencies and formed ice at RHice values well below homogeneous ice nucleation limits. The data show that the chemical composition of these eld{collected particles plays an important role in determining water uptake and immersion freezing. Heterogeneous ice nucleation rate coeffcients, cumulative ice nuclei (IN) spectrum, and IN activated fraction for deposition ice nucleation are derived. The presented ice nucleation data demonstrate that anthropogenic and marine particles comprising of various chemical and physical properties exhibit distinctly different ice nucleation effciencies and can serve as effcient IN at atmospheric conditions typical for cirrus and mixed phase clouds. This indicates a potential link between human activities and cloud formation, and thus climate.

Wang, Bingbing; Laskin, Alexander; Roedel, Tobias R.; Gilles, Marry K.; Moffet, Ryan C.; Tivanski, Alexei V.; Knopf, Daniel A.

2012-09-25T23:59:59.000Z

446

Macroscopic description of the interaction between two complex nuclei  

SciTech Connect

Assuming that the particle number is large, and using the leptodermous idealization that the ratio of the surface thickness to the cube root of nuclear volume is very small, an attempt is made to give an account of the time evolution of the shape of a nuclear system. It is suggested that a one-body, dissipation dominated approach to nuclear dynamics should be a reasonable starting point. (SDF)

Swiatecki, W.J.

1975-09-01T23:59:59.000Z

447

Simulation and Analysis of a Tissue Equivalent Proportional Counter Using the Monte Carlo Transport Code FLUKA  

E-Print Network (OSTI)

The purpose of this study was to determine how well the Monte Carlo transport code FLUKA can simulate a tissue-equivalent proportional counter (TEPC) and produce the expected delta ray events when exposed to high energy heavy ions (HZE) like in the galactic cosmic ray (GCR) environment. Accurate transport codes are desirable because of the high cost of beam time, the inability to measure the mixed field GCR on the ground and the flexibility they offer in the engineering and design process. A spherical TEPC simulating a 1 um site size was constructed in FLUKA and its response was compared to experimental data for an 56Fe beam at 360 MeV/nucleon. The response of several narrow beams at different impact parameters were used to explain the features of the response of the same detector exposed to a uniform field of radiation. Additionally, an investigation was made into the effect of the wall thickness on the response of the TEPC and the range of delta rays in the tissue-equivalent (TE) wall material. A full impact parameter test (from IP = 0 to IP = detector radius) was performed to show that FLUKA produces the expected wall effect. That is, energy deposition in the gas volume can occur even when the primary beam does not pass through the gas volume. A final comparison to experimental data was made for the simulated TEPC exposed to various broad beams in the energy range of 200 - 1000 MeV/nucleon. FLUKA overestimated energy deposition in the gas volume in all cases. The FLUKA results differed from the experimental data by an average of 25.2 % for yF and 12.4 % for yD. It is suggested that this difference can be reduced by adjusting the FLUKA default ionization potential and density correction factors.

Northum, Jeremy Dell

2010-05-01T23:59:59.000Z

448

Computer-optimized design of polyethylene-moderated {sup 3}He counters for fast neutrons  

Science Conference Proceedings (OSTI)

Because polyethylene-moderated {sup 3}He counters are rugged and reliable, they are generally the instruments of choice for field detection of fast neutrons in gamma-ray backgrounds. Their main drawback is the bulky, massive moderator needed to reduce the incident neutron energies to the sensitive range of the {sup 3}He+n capture reaction. This report discusses an optimization approach that provides a detector with uniform angular response and the maximum detection efficiency per unit mass. The key assumption is that each parameter has a geometrical interpretation and its effect on the response can be evaluated independently from that of the others. Specifically, the detection efficiency can be written as a product of separate functions for the moderator mass, gas pressure, tube position, etc., and the uniformity of the angular response is determined by the symmetry of the moderator dimensions. This analytical model was tested by compiling a comprehensive database of detector efficiencies as functions of the different parameters, including one- versus two-tube detectors, moderator masses from 1 to 6 kg, gas pressures from 1 to 20 atm, etc. In general, the model reproduced both the magnitude and angular dependence of the efficiency to within about 10%. To a high degree, the most important parameters are polyethylene mass and the quantity of {sup 3}He gas; because of neutron diffusion out of the moderator, the optimum tube positions are near the center of the detector. The highest value of the efficiency per unit mass occurs near 3 kg, a result that requires the most compact detectors to use more than a single {sup 3}He tube. In this case, the optimum detector has two tubes and a total mass of 3.0 kg. Although they could use 4-atm tubes with 2.54-cm diameters, increasing the gas volume could easily provide a 20% increase in efficiency with no changes in other parameters.

R. C. Byrd

2000-05-01T23:59:59.000Z

449

ADVANCES IN THE RXTE PROPORTIONAL COUNTER ARRAY CALIBRATION: NEARING THE STATISTICAL LIMIT  

SciTech Connect

During its 16 years of service, the Rossi X-Ray Timing Explorer (RXTE) mission has provided an extensive archive of data, which will serve as a primary source of high cadence observations of variable X-ray sources for fast timing studies. It is, therefore, very important to have the most reliable calibration of RXTE instruments. The Proportional Counter Array (PCA) is the primary instrument on board RXTE which provides data in 3-50 keV energy range with submillisecond time resolution in up to 256 energy channels. In 2009, the RXTE team revised the response residual minimization method used to derive the parameters of the PCA physical model. The procedure is based on the residual minimization between the model spectrum for Crab Nebula emission and a calibration data set consisting of a number of spectra from the Crab and the on-board Am{sub 241} calibration source, uniformly covering the whole RXTE mission operation period. The new method led to a much more effective model convergence and allowed for better understanding of the PCA energy-to-channel relationship. It greatly improved the response matrix performance. We describe the new version of the RXTE/PCA response generator PCARMF v11.7 (HEASOFT Release 6.7) along with the corresponding energy-to-channel conversion table (version e05v04) and their difference from the previous releases of PCA calibration. The new PCA response adequately represents the spectrum of the calibration sources and successfully predicts the energy of the narrow iron emission line in Cas-A throughout the RXTE mission.

Shaposhnikov, Nikolai [CRESST and Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Jahoda, Keith; Markwardt, Craig; Swank, Jean; Strohmayer, Tod, E-mail: nikolai.v.shaposhnikov@nasa.gov [Astrophysics Science Division, Goddard Space Flight Center, NASA, Greenbelt, MD 20771 (United States)

2012-10-01T23:59:59.000Z

450

The Particle Adventure | How do we experiment with tiny particles? |  

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

Accelerating particles Accelerating particles Accelerating particles It is fairly easy to obtain particles. Physicists get electrons by heating metals; they get protons by robbing hydrogen of its electron; etc. Accelerators speed up charged particles by creating large electric fields which attract or repel the particles. This field is then moved down the accelerator, "pushing" the particles along. In a linear accelerator the field is due to traveling electromagnetic (E-M) waves. When an E-M wave hits a bunch of particles, those in the back get the biggest boost, while those in the front get less of a boost. In this fashion, the particles "ride" the front of the E-M wave like a bunch of surfers. The next page shows this process in an easier to understand animation

451

Inclusive neutral particle production  

SciTech Connect

Results of recent inclusive neutral particle production experiments are compared to existing experimental results. These experiments range from 15 to 2000 GeV/c in laboratory beam momentum and use $pi$$sup -$, $pi$$sup +$, p and anti p beams. (auth)

Kahn, S.

1975-01-01T23:59:59.000Z

452

RESONATOR PARTICLE SEPARATOR  

DOE Patents (OSTI)

A wave-guide resonator structure is designed for use in separating particles of equal momentum but differing in mass, having energies exceeding one billion eiectron volts. The particles referred to are those of sub-atomic size and are generally produced as a result of the bombardment of a target by a beam such as protons produced in a high energy accelerator. In the resonator a travelling electric wave is produced which travels at the same rate of speed as the unwanted particle which is thus deflected continuously over the length of the resonator. The wanted particle is slightly out of phase with the travelling wave so that over the whole length of the resonator it has a net deflection of substantially zero. The travelling wave is established in a wave guide of rectangular cross section in which stubs are provided to store magnetic wave energy leaving the electric wave energy in the main structure to obtain the desired travelling wave and deflection. The stubs are of such shape and spacing to establish a critical mathemitical relationship. (AEC)

Blewett, J.P.; Kiesling, J.D.

1963-06-11T23:59:59.000Z

453

Matter: the fundamental particles  

E-Print Network (OSTI)

"The largest particle physics centre in the world is located in Europe. It straddles the Franco-Swiss border, near Geneva. At CERN - the European Organisation for Nuclear Research , which is focused on the science of nuclear matter rather than on the exploitation of atomic energy - there are over 6 500 scientists." (1 page)

Landua, Rolf

2007-01-01T23:59:59.000Z

454

Perturbative Study of Energetic Particle Redistribution by Alfven Eigenmodes in ITER  

SciTech Connect

The modification of particle distributions by magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles. Flattening of a distribution due to phase mixing in an island or due to portions of phase space becoming stochastic is a process extremely rapid on the time scale of an experiment. In this paper we examine the effect of toroidal Alfven eigenmodes (TAE) and reversed shear Alfven eigenmodes (RSAE) in ITER on alpha particle and injected beam distributions using theoretically predicted mode amplitudes. It is found that for the equilibrium of a hybrid scenario even at ten times the predicted saturation level the modes have negligible effect on these distributions. A strongly reversed shear (or advanced) scenario, having a spectrum of modes that are much more global, is somewhat more susceptible to induced loss due to mode resonance, with alpha particle losses of over one percent with predicted amplitudes and somewhat larger with the assistance of toroidal field ripple. The elevated q profile contributes to stronger TAE (RSAE) drive and more unstable modes. An analysis of the existing mode-particle resonances is carried out to determine which modes are responsible for the profile modification and induced loss. We find that losses are entirely due to resonance with the counter-moving and trapped particle populations, with co-moving passing particles participating in resonances only deep within the plasma and not leading to loss.

N.N. Gorelenkov and R.B. White

2012-10-29T23:59:59.000Z

455

STRATIGRAPHY OF COUNTER-POINT-BAR AND EDDY-ACCRETION DEPOSITS IN LOW-ENERGY MEANDER BELTS OF THE PEACE-ATHABASCA  

E-Print Network (OSTI)

STRATIGRAPHY OF COUNTER-POINT-BAR AND EDDY-ACCRETION DEPOSITS IN LOW-ENERGY MEANDER BELTS-7th Ave. SW, Nexen Inc., Calgary, AB, T2P 3P7, Canada ABSTRACT: Previously termed concave bank

456

Role of particle conservation in self-propelled particle systems  

E-Print Network (OSTI)

Actively propelled particles undergoing dissipative collisions are known to develop a state of spatially distributed coherently moving clusters. For densities larger than a characteristic value clusters grow in time and form a stationary well-ordered state of coherent macroscopic motion. In this work we address two questions: (i) What is the role of the particles' aspect ratio in the context of cluster formation, and does the particle shape affect the system's behavior on hydrodynamic scales? (ii) To what extent does particle conservation influence pattern formation? To answer these questions we suggest a simple kinetic model permitting to depict some of the interaction properties between freely moving particles and particles integrated in clusters. To this end, we introduce two particle species: single and cluster particles. Specifically, we account for coalescence of clusters from single particles, assembly of single particles on existing clusters, collisions between clusters, and cluster disassembly. Coarse-graining our kinetic model, (i) we demonstrate that particle shape (i.e. aspect ratio) shifts the scale of the transition density, but does not impact the instabilities at the ordering threshold. (ii) We show that the validity of particle conservation determines the existence of a longitudinal instability, which tends to amplify density heterogeneities locally, and in turn triggers a wave pattern with wave vectors parallel to the axis of macroscopic order. If the system is in contact with a particle reservoir this instability vanishes due to a compensation of density heterogeneities.

Christoph A. Weber; Florian Thüroff; Erwin Frey

2013-01-31T23:59:59.000Z

457

Integral charged particle nuclear date bibliography. Editon 1, Supplement 2  

Science Conference Proceedings (OSTI)

This bibliography is divided into three sections, ''References'', ''Target Index'', and ''Residual Index.'' The ''References'' section contains all references satisfying the following criteria: excitation functions, thick targets, or product yield leading to the formation of a ground or metastable state; the atomic mass and charge of the incident particle must be greater than or equal to 1; the atomic mass of the target must be greater than or equal to 1; and the atomic masses of the outgoing and residual nuclei must be greater than or equal to 1 with the exception of processes which do not lead to a definite residual nucleus and of gamma-ray production cross sections. The ''Target Index'' section contains the incident particle energy and the abbreviated reference lines for all the entries, which contain information on a definite target nucleus and reaction. These reference lines contain the Journal name, followed by the volume and page number. The ''Residual Index'' section also contains the incident particle energy and the abbreviated reference lines for all the entries, which contain information on a definite residual nucleus and a definite target-reaction.

Holden, N.E.; Ramavataram, S.; Dunford, C.L.

1986-04-01T23:59:59.000Z

458

Particle measurement systems and methods  

SciTech Connect

A system according to one embodiment includes a light source for generating light fringes; a sampling mechanism for directing a particle through the light fringes; and at least one light detector for detecting light scattered by the particle as the particle passes through the light fringes. A method according to one embodiment includes generating light fringes using a light source; directing a particle through the light fringes; and detecting light scattered by the particle as the particle passes through the light fringes using at least one light detector.

Steele, Paul T. (Livermore, CA)

2011-10-04T23:59:59.000Z

459

Bar-driven fueling of galactic nuclei: a 2D view  

E-Print Network (OSTI)

I discuss evidences for bar-driven gas fueling in the central regions of galaxies, focusing on scales down to about 10 pc. I thus mention the building of inner disks, and the link with resonances, as well as the corresponding kinematic signatures such as sigma-drops and counter-rotating nuclear disks as probed via integral-field spectroscopy.

Emsellem, E

2004-01-01T23:59:59.000Z

460

THE SURVIVAL OF NUCLEI IN JETS ASSOCIATED WITH CORE-COLLAPSE SUPERNOVAE AND GAMMA-RAY BURSTS  

SciTech Connect

Heavy nuclei such as nickel-56 are synthesized in a wide range of core-collapse supernovae (CCSN), including energetic supernovae associated with gamma-ray bursts (GRBs). Recent studies suggest that jet-like outflows are a common feature of CCSN. These outflows may entrain synthesized nuclei at launch or during propagation, and provide interesting multi-messenger signals including heavy ultra-high-energy cosmic rays. Here, we investigate the destruction processes of nuclei during crossing from the stellar material into the jet material via a cocoon, and during propagation after being successfully loaded into the jet. We find that nuclei can survive for a range of jet parameters because collisional cooling is faster than spallation. While canonical high-luminosity GRB jets may contain nuclei, magnetic-dominated models or low-luminosity jets with small bulk Lorentz factors are more favorable for having a significant heavy nuclei component.

Horiuchi, Shunsaku; Murase, Kohta [Center for Cosmology and Astro-Particle Physics, Ohio State University, 191 West Woodruff Avenue, Columbus, OH 43210 (United States); Ioka, Kunihito [KEK Theory Center and Graduate University for Advanced Studies (Sokendai), Tsukuba 305-0801 (Japan); Meszaros, Peter [Department of Astronomy and Astrophysics, Department of Physics and Center for Particle Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States)

2012-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "nuclei particle counter" 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.


461

A Distribution of Large Particles in the Coma of Comet 103P/Hartley 2  

E-Print Network (OSTI)

The coma of comet 103P/Hartley 2 has a significant population of large particles observed as point sources in images taken by the Deep Impact spacecraft. We measure their spatial and flux distributions, and attempt to constrain their composition. The flux distribution of these particles implies a very steep size distribution with power-law slopes ranging from -6.6 to -4.7. The radii of the particles extend up to 20 cm, and perhaps up to 2 m, but their exact sizes depend on their unknown light scattering properties. We consider two cases: bright icy material, and dark dusty material. The icy case better describes the particles if water sublimation from the particles causes a significant rocket force, which we propose as the best method to account for the observed spatial distribution. Solar radiation is a plausible alternative, but only if the particles are very low density aggregates. If we treat the particles as mini-nuclei, we estimate they account for <16-80% of the comet's total water production rate (...

Kelley, Michael S; Bodewits, Dennis; A'Hearn, Michael F; Lisse, Carey M; Kolokolova, Ludmilla; Kissel, Jochen; Hermalyn, Brendan; 10.1016/j.icarus.2012.09.037

2013-01-01T23:59:59.000Z

462

Small Particles in Cirrus  

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

Particles in Cirrus Particles in Cirrus Because the reflective properties of ice crystals in cirrus clouds can greatly influence the amount of solar energy that reaches the Earth, scientists use information about the shape and size of ice crystals as input to climate models. These data are obtained by satellite instruments, ground-based sensors, and research aircraft equipped with probes. However, notable discrepancies among these measurements have led to considerable uncertainty in how to represent these properties in climate models. From December 2009 through April 2010, the Atmospheric Radiation Measurement (ARM) Climate Research Facility will sponsor the use of an instrumented aircraft to obtain the most comprehensive set of measurements of ice crystals in cirrus clouds yet obtained. In conjunction with

463

Particle Data Group  

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

About PDG About PDG About the PDG PDG authors Order PDG products PDG citation Encoder tools Job at LBNL Contact Us Downloads Resources Errata Archives Atomic Nuclear Properties Online HEP Info Non-PDG Databases Durham-RAL databases Current experiments Guide to Data Partial-wave analyses Contact Us News The "Reviews, Tables, Plots" section has been updated. The next book edition is due in early summer 2014, and the booklet in late summer 2014. Funded By: US DOE US NSF CERN MEXT (Japan) INFN (Italy) MEC (Spain) IHEP & RFBR (Russia) Mirrors: USA (LBNL) Brazil CERN Indonesia Italy Japan (KEK) Russia (Novosibirsk) Russia (Protvino) UK (Durham) The Review of Particle Physics J. Beringer et al. (Particle Data Group), Phys. Rev. D86, 010001 (2012) and 2013 partial update for the 2014 edition.

464

Particle Data Group - Authors  

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

6 Edition and 2007 Web Update 6 Edition and 2007 Web Update (Click on Author Name to get Email address, phone numbers, etc.) RPP authors New authors of 2007 Web Update M. Antonelli, 102 H. Baer, 64 G. Bernardi, 103 M. Carena, 51 M.-C. Chen, 11 B. Dobrescu, 51 J.-F. Grivaz, 104 T. Gutsche, 105 J. Huston, 45 T. Junk, 51 C.-J. Lin, 1 H. Mahlke, 106 P. Mohr, 107 P. Nevski, 75 S. Rolli, 108 A. Romaniouk, 109 B. Seligman, 110 M. Shaevitz, 111 B. Taylor, 107 M. Titov, 56,112 G. Weiglein, 78 A. Wheeler, 69 Authors of the 2006 Review of Particle Physics W.-M. Yao et al. (Particle Data Group), J. Phys. G 33, 1 (2006) (bibtex format) Also see: PS format or PDF format. AUTHORS OF LISTINGS AND REVIEWS: (Click on Author Name to get Email address, phone numbers, etc.) RPP authors (RPP 2006)

465

Particle detector spatial resolution  

DOE Patents (OSTI)

Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

Perez-Mendez, V.

1992-12-15T23:59:59.000Z

466

The Particle Adventure | How do we experiment with tiny particles...  

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

Accelerating particles: Animation The above is an animation of the following concept: This is a test search string for google...

467

``Hot particle`` intercomparison dosimetry  

SciTech Connect

Dosimetry measurements of four ``hot particles`` were made at different density thickness values using five different methods. The hot particles had maximum dimensions of 650 {mu}m and maximum beta energies of 0.97, 046, 0.36 and 0.32 MeV. Absorbers were used to obtain the dose at different depths for each dosimeter. Measurements were made using exoelectron dosimeters, an extrapolation chamber, NE extremity tape dosimeters, Eberline RO-2 and RO-2A survey meters, and two sets of GafChromic dye film with each set read out at a different institution. From these results the dose was calculated averaged over 1 cm{sup 2} of tissue at 18, 70, 125, and 400 {mu}m depth. Comparisons of tissue-dose averaged over 1 cm{sup 2} for 18, 70 and 125 {mu}m depth based on interpolated measured values, were within 30% for the GafChromic dye film, extrapolation chamber, NE Extremity Tape dosimeters, and Eberline RO-2 and 2A survey meters except for the hot particle with 0.46 MeV maximum beta energy. The results for this source showed differences of up to 60%. The extrapolation chamber and NE Extremity Tape dosimeters under-responded for measurements at 400 {mu}m by about a factor of 2 compared with the Gaf Chromic dye films for two hot particles with maximum beta energy of 0.32 and 0.36 MeV which each emitted two 100% 1 MeV photons per disintegration. Tissue doses determined using exoelectron dosimeters were a factor of 2 to 5 less than those determined using other dosimeters, possibly due to failures of the equipment.

Kaurin, D.G.L.; Baum, J.W. [Brookhaven National Lab., Upton, NY (United States); Charles, M.W.; Darley, D.P.J. [Birmingham Univ. (United Kingdom); Durham, J.S. [Pacific Northwest Lab., Richland, WA (United States); Scannell, M.J. [Yankee Atomic Electric Co., Bolton, MA (United States); Soares, C.G. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1996-06-01T23:59:59.000Z

468

Radiation in Particle Simulations  

SciTech Connect

Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of megabars to thousands of gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present four methods that attempt a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The first method applies the Lienard-Weichert solution of Maxwell's equations for a classical particle whose motion is assumed to be known. The second method expands the electromagnetic field in normal modes (planewaves in a box with periodic boundary-conditions) and solves the equation for wave amplitudes coupled to the particle motion. The third method is a hybrid molecular dynamics/Monte Carlo (MD/MC) method which calculates radiation emitted or absorbed by electron-ion pairs during close collisions. The fourth method is a generalization of the third method to include small clusters of particles emitting radiation during close encounters: one electron simultaneously hitting two ions, two electrons simultaneously hitting one ion, etc. This approach is inspired by the virial expansion method of equilibrium statistical mechanics. Using a combination of these methods we believe it is possible to do atomic-scale particle simulations of fusion ignition plasmas including the important effects of radiation emission and absorption.

More, R; Graziani, F; Glosli, J; Surh, M

2010-11-19T23:59:59.000Z

469

Particle production at HERA  

E-Print Network (OSTI)

H1 has measured a number of different known particles and compared their production to QCD models and to other reactions such