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Note: This page contains sample records for the topic "gamma radiation levels" 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.


1

Gamma radiation field intensity meter  

DOE Patents [OSTI]

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

Thacker, L.H.

1995-10-17T23:59:59.000Z

2

Gamma radiation field intensity meter  

DOE Patents [OSTI]

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

Thacker, L.H.

1994-08-16T23:59:59.000Z

3

Gamma radiation field intensity meter  

DOE Patents [OSTI]

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

Thacker, Louis H. (Knoxville, TN)

1995-01-01T23:59:59.000Z

4

Gamma radiation field intensity meter  

DOE Patents [OSTI]

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

Thacker, Louis H. (Knoxville, TN)

1994-01-01T23:59:59.000Z

5

Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture  

SciTech Connect (OSTI)

The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

Scott Wilde, Raymond Keegan

2008-07-01T23:59:59.000Z

6

Apparatus and method for detecting gamma radiation  

DOE Patents [OSTI]

A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

Sigg, Raymond A. (Martinez, GA)

1994-01-01T23:59:59.000Z

7

Apparatus and method for detecting gamma radiation  

DOE Patents [OSTI]

A high efficiency radiation detector is disclosed for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data. 4 figures.

Sigg, R.A.

1994-12-13T23:59:59.000Z

8

Composition and apparatus for detecting gamma radiation  

DOE Patents [OSTI]

A gamma radiation detector and a radioluminescent composition for use therein. The detector includes a radioluminescent composition that emits light in a characteristic wavelength region when exposed to gamma radiation, and means for detecting said radiation. The composition contains a scintillant such as anglesite (PbSO[sub 4]) or cerussite (PbCO[sub 3]) incorporated into an inert, porous glass matrix via a sol-gel process. Particles of radiation-sensitive scintillant are added to, a sol solution. The mixture is polymerized to form a gel, then dried under conditions that preserve the structural integrity and radiation sensitivity of the scintillant. The final product is a composition containing the uniformly-dispersed scintillant in an inert, optically transparent and highly porous matrix. The composition is chemically inert and substantially impervious to environmental conditions including changes in temperature, air pressure, and so forth. It can be fabricated in cylinders, blocks with holes therethrough for flow of fluid, sheets, surface coatings, pellets or other convenient shapes. 3 figs.

Hofstetter, K.J.

1994-08-09T23:59:59.000Z

9

A Device for Search of Gamma-Radiation Intensive Sources at the Radiation Accident Condition  

SciTech Connect (OSTI)

The procedure designed for measuring angular distributions of gamma radiation and for search of gamma radiation intensive sources is described. It is based on application of the original multidetector device ShD-1, for measuring an angular distribution in a complete solid angle (4 pi). The calibration results and data on the angular distributions of intensity of gamma radiation at the roof of Chornobyl NPP ''Shelter'' are presented.

Batiy, Valeriy; Klyuchnykov, A; Kochnev, N; Rudko, Vladimir; shcherbin, vladimir; Yegorov, V; Schmieman, Eric A.

2005-08-08T23:59:59.000Z

10

LATTICE DYNAMICS NUCLEAR RESONANCE ABSORPTION OF GAMMA-RADIATION  

E-Print Network [OSTI]

crystalline domains are taken. Absorption studies of the dynamics of atomic motions in condensed matterLATTICE DYNAMICS NUCLEAR RESONANCE ABSORPTION OF GAMMA-RADIATION AND COHERENT DECAY MODES Institut Max von Laue-Paul Langevin, Grenoble, France R6sumb. -La section efficace pour l'absorption nucleaire

Paris-Sud XI, Université de

11

E-Print Network 3.0 - acute gamma radiation Sample Search Results  

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

expressions for the spectral evolution of the early afterglow radiation from gamma-ray bursts... this transition, the radiative efficiency will steadily decrease as ffl ...

12

E-Print Network 3.0 - aux radiations gamma Sample Search Results  

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

expressions for the spectral evolution of the early afterglow radiation from gamma-ray bursts... this transition, the radiative efficiency will steadily decrease as ffl ...

13

PCB Radiation Mechanisms: Using Component-Level Measurements to  

E-Print Network [OSTI]

1 PCB Radiation Mechanisms: Using Component-Level Measurements to PCB Radiation Mechanisms: Using Component-Level Measurements to Determine System-Level Radiated EmissionsDetermine System-Level Radiated Radiation Directly from PCB StructuresRadiation Directly from PCB Structures Signal or component voltage

Stuart, Steven J.

14

Gamma Radiation & X-Rays  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun with Big Sky Learning Fun with Big SkyDIII-DRMRGamma Radiation and X-Rays 1.

15

Health effects of low-level radiation in shipyard workers. Final report: [Draft  

SciTech Connect (OSTI)

The Nuclear Shipyard Workers Study (NSWS) was designed to determine whether there is an excess risk of leukemia or other cancers associated with exposure to low levels of gamma radiation. The study compares the mortality experience of shipyard workers who qualified to work in radiation areas to the mortality of similar workers who hold the same types of jobs but who are not authorized to work in radiation areas. The population consists of workers from six government and two private shipyards.

Matanoski, G.M.

1991-06-01T23:59:59.000Z

16

HEALTH EFFECTS OF LOW-LEVEL IONIZING RADIATION  

E-Print Network [OSTI]

LO~Z-lEVEL IONIZIN(l RADIATION Jacob I . Fabti kant April ··OF LOW~LEVEL IONIZING RADIATION BEFORE THE SUBCOMMITTEE ONwill low~level ionizing radiation. restricted primarily to

Fabrikant, Jacob I.

2012-01-01T23:59:59.000Z

17

Current Trends in Gamma Radiation Detection for Radiological Emergency Response  

SciTech Connect (OSTI)

Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of interdisciplinary research and development has taken place–techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation–the so-called second line of defense.

Mukhopadhyay, S., Guss, P., Maurer, R.

2011-09-01T23:59:59.000Z

18

Gamma thermometer based reactor core liquid level detector  

DOE Patents [OSTI]

A system is provided which employs a modified gamma thermometer for determining the liquid coolant level within a nuclear reactor core. The gamma thermometer which normally is employed to monitor local core heat generation rate (reactor power), is modified by thermocouple junctions and leads to obtain an unambiguous indication of the presence or absence of coolant liquid at the gamma thermometer location. A signal processor generates a signal based on the thermometer surface heat transfer coefficient by comparing the signals from the thermocouples at the thermometer location. The generated signal is a direct indication of loss of coolant due to the change in surface heat transfer when coolant liquid drops below the thermometer location. The loss of coolant indication is independent of reactor power at the thermometer location. Further, the same thermometer may still be used for the normal power monitoring function.

Burns, Thomas J. (Knoxville, TN)

1983-01-01T23:59:59.000Z

19

E-Print Network 3.0 - attenuates gamma radiation Sample Search...  

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

Astrophysics Research Group Collection: Physics 60 MilagroA TeV Observatory for Gamma Ray Bursts Summary: to gamma rays is likely to complement synchrotron radiation and produce...

20

EFFECTS OF GAMMA RADIATION ON ELECTROCHEMICAL PROPERTIES OF IONIC LIQUIDS  

SciTech Connect (OSTI)

The electrochemical properties of ionic liquids (ILs) make them attractive for possible replacement of inorganic salts in high temperature molten salt electrochemical processing of nuclear fuel. To be a feasible replacement solvent, ILs need to be stable in moderate and high doses of radiation without adverse chemical and physical effects. Here, we exposed seven different ILs to a 1.2 MGy dose of gamma radiation to investigate their physical and chemical properties as they related to radiological stability. The azolium-based ILs experienced the greatest change in appearance, but these ILs were chemically more stable to gamma radiation than some of the other classes of ILs tested, due to the presence of aromatic electrons in the azolium ring. All the ILs exhibited a decrease in their conductivity and electrochemical window (at least 1.1 V), both of which could affect the utility of ILs in electrochemical processing. The concentration of the irradiation decomposition products was less than 3 mole %, with no impurities detectable using NMR techniques.

Visser, A; Nicholas Bridges, N; Thad Adams, T; John Mickalonis, J; Mark02 Williamson, M

2009-04-21T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Gravitational radiation from long gamma-ray bursts  

E-Print Network [OSTI]

Long gamma-ray bursts (GRBs) are probably powered by high-angular momentum black hole-torus systems in suspended accretion. The torus will radiate gravitational waves as non-axisymmetric instabilities develop. The luminosity in gravitational-wave emissions is expected to compare favorably with the observed isotropic equivalent luminosity in GRB-afterglow emissions. This predicts that long GRBs are potentially the most powerful LIGO/VIRGO burst-sources in the Universe. Their frequency-dynamics is characterized by a horizontal branch in the $\\dot{f}(f)-$diagram.

Maurice H. P. M. van Putten

2001-02-11T23:59:59.000Z

22

Determining the Impact of Concrete Roadways on Gamma Ray Background Readings for Radiation Portal Monitoring Systems  

E-Print Network [OSTI]

country of origin. To combat the threat of nuclear trafficking, radiation portal monitors (RPMs) are deployed around the world to intercept illicit material while in transit by passively detecting gamma and neutron radiation. Portal monitors in some...

Ryan, Christopher Michael

2012-07-16T23:59:59.000Z

23

Effects of gamma radiation on Serratia marcescens; a comparison of effects of two different exposure rates  

E-Print Network [OSTI]

'Donovan, Effect of gamma radiation on Serratia marcescens: Comparison of the radiosensi- tivity of pigmented and nonpigmented cells. Radiation Res, 48, 40-52 (1971). 18. Alison P. Casarett, Radiation ~Biolo . p. 159. Prentice-Hall, Inc. , Englewood Cliffs... EFFECTS OF GAMMA RADIATION ON SL'RNATIA MARCESCENS A COMPARISON OF EFFECTS OF TWO DIFFERENT EXPOSURE RATES A Thesis by CHRISTY ANNETTE MOORE Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements...

Moore, Christy Annette

1972-01-01T23:59:59.000Z

24

Neutron and gamma radiation shielding material, structure, and process of making structure  

DOE Patents [OSTI]

The present invention is directed to a novel neutron and gamma radiation elding material consisting of 95 to 97 percent by weight SiO.sub.2 and 5 to 3 percent by weight sodium silicate. In addition, the method of using this composition to provide a continuous neutron and gamma radiation shielding structure is disclosed.

Hondorp, Hugh L. (Princeton Junction, NJ)

1984-01-01T23:59:59.000Z

25

Radiation-Induced Carcinogenesis: Mechanistically Based Differences between Gamma-Rays and Neutrons, and  

E-Print Network [OSTI]

Radiation-Induced Carcinogenesis: Mechanistically Based Differences between Gamma-Rays and Neutrons of Radiation Oncology, The University of Texas Medical Branch, Galveston, Texas, United States of America Abstract Different types of ionizing radiation produce different dependences of cancer risk on radiation

Brenner, David Jonathan

26

ON THE KINETIC ENERGY AND RADIATIVE EFFICIENCY OF GAMMA-RAY BURSTS Nicole M. Lloyd-Ronning1  

E-Print Network [OSTI]

ON THE KINETIC ENERGY AND RADIATIVE EFFICIENCY OF GAMMA-RAY BURSTS Nicole M. Lloyd-Ronning1 of 17 gamma-ray bursts (GRBs) during the afterglow phase and ac- counting for radiative losses, we the implications of these results for the GRB radiation and jet models. Subject headinggs: gamma rays: bursts

Zhang, Bing

27

Studies in feed spoilage: prevention of spoilage in ground corn by gamma radiation  

E-Print Network [OSTI]

of gam- 6 ma radiation. If gamma rays can be used to preserve foods, it seems pos- sible that they may be used also to prevent losses in grains, feed ingred- ients, and mixed feeds. It is anticipated that the dose high enough to destroy insects... not been studied extensively. Investigations on the use of gamma radiation for the preservation of various feed ingredients need to be carried out to determine: (I) the effect of gamma radiation on the growth of molds im feeds irradiated at different...

Webb, Billy Dean

1959-01-01T23:59:59.000Z

28

Virtuality Distributions in application to gamma gamma* to pi^0 Transition Form Factor at Handbag Level  

SciTech Connect (OSTI)

We outline basics of a new approach to transverse momentum dependence in hard processes. As an illustration, we consider hard exclusive transition process gamma*gamma -> to pi^0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O(0,z)) describing a hadron with momentum p. Treated as functions of (pz) and z^2, they are parametrized through a virtuality distribution amplitude (VDA) Phi (x, sigma), with x being Fourier-conjugate to (pz) and sigma Laplace-conjugate to z^2. For intervals with z^+=0, we introduce transverse momentum distribution amplitude (TMDA) Psi (x, k_\\perp), and write it in terms of VDA Phi (x, \\sigma). The results of covariant calculations, written in terms of Phi (x sigma) are converted into expressions involving Psi (x, k_\\perp. Starting with scalar toy models, we extend the analysis onto the case of spin-1/2 quarks and QCD. We propose simple models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data on the pion transition form factor. We also discuss how one can generate high-k_\\perp tails from primordial soft distributions.

Radyushkin, Anatoly V. [ODU, JLAB

2014-07-01T23:59:59.000Z

29

A ground level gamma-ray burst observed in association with rocket-triggered lightning  

E-Print Network [OSTI]

A ground level gamma-ray burst observed in association with rocket-triggered lightning J. R. Dwyer 2004; published 13 March 2004. [1] We report the observation of an intense gamma-ray burst observed lightning channel with gamma-ray energies extending up to more than 10 MeV. The burst consisted of 227

Florida, University of

30

Effects of High Dietary Iron and Gamma Radiation on Oxidative Stress and Bone  

E-Print Network [OSTI]

(induced by feeding a high iron diet) and gamma radiation exposure would independently increase markers of oxidative stress and markers of oxidative damage and result in loss of bone mass, with the combined treatment having additive or synergistic effects...

Yuen, Evelyn P

2013-04-19T23:59:59.000Z

31

Detection system for high-resolution gamma radiation spectroscopy with neutron time-of-flight filtering  

DOE Patents [OSTI]

A .gamma.-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive .alpha.-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a .gamma.-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the .gamma.-radiation. Subsequently, it is determined whether a coincidence exists between the .alpha.-particles and .gamma.-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the .alpha.-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.

Dioszegi, Istvan; Salwen, Cynthia; Vanier, Peter

2014-12-30T23:59:59.000Z

32

E-Print Network 3.0 - activity gamma radiation Sample Search...  

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

no. (will be inserted by hand later) Summary: as a function of time. Key words: Gamma ray : bursts -- Shock waves -- ISM : jets and outflous -- Radiation... .10.1; 02.18.5...

33

Effect of gamma radiation on selected functional and physical properties of liquid egg white  

E-Print Network [OSTI]

had larger air cells with thicker cell walls. The cakes were also tougher and had more resistance to compression. CHAPTER I II EFFECT OF GAMMA RADIATION ON SELECTED PHYSICAL PROPERTIES OF LIqUID EGG WHITE Intr oduct ion As indi. cated in Chapter... EFFECT OF GAMMA RADIATION ON SELECTED FUNCTIONAL AND PHYSICAL PROPERTIES OF LIQUID EGG WHITE A Thesis By Hershell Ray Ball, Jr. Approved as to style and content by) (Chairman of Committee) ead of Department) (Me mba (Member) ( ber) ~Ja...

Ball, Hershell Ray

1966-01-01T23:59:59.000Z

34

Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses  

SciTech Connect (OSTI)

Gamma radiation induces changes in physical, optical, and structural properties in chalcogenide glasses., Previous research has focused on As{sub 2}S{sub 3} and families of glasses containing Ge. For the first time, we present composition and dose dependent data on the As-S binary glass series. Binary As{sub x}S{sub 100-x} (x = 30, 33, 36, 40, and 42) glasses were irradiated with gamma radiation using a {sup 60}Co source at 2.8 Gy/s to accumulated doses of 1, 2, 3, and 4 MGy. The irradiated samples were characterized at each dose level for density, refractive index, x-ray diffraction, and Raman spectrum. These results are compared to those of as-made and 1 year aged samples. We report an initial increase in density followed by a decrease as a function of dose that contradicts the expected compositional dependence of molar volume of these glasses. This unusual behavior is explained based on microvoid formation and nanoscale phase-separation induced by the irradiation in these glasses. XRD, Raman, and EPR data provide supporting evidence, underscoring the importance of optimally- or overly-constrained structures for stability under aging or irradiation.

Sundaram, S. K.; McCloy, John S.; Riley, Brian J.; Murphy, Mark K.; Qiao, Hong (Amy) [Amy; Windisch, Charles F.; Walter, Eric D.; Crum, Jarrod V.; Golovchak, Roman; Shpotyuk, O.

2012-03-01T23:59:59.000Z

35

Relativistic Winds from Compact Gamma-Ray Sources: II. Pair Loading and Radiative Acceleration in Gamma-ray Bursts  

E-Print Network [OSTI]

We consider the effects of rapid pair creation by an intense pulse of gamma-rays propagating ahead of a relativistic shock. Side-scattered photons colliding with the main gamma-ray beam amplify the density of scattering charges. The acceleration rate of the pair-loaded medium is calculated, and its limiting bulk Lorentz factor related to the spectrum and compactness of the photon source. One obtains, as a result, a definite prediction for the relative inertia in baryons and pairs. The deceleration of a relativistic shock in the moving medium, and the resulting synchrotron emissivity, are compared with existing calculations for a static medium. The radiative efficiency is increased dramatically by pair loading. When the initial ambient density exceeds a critical value, the scattering depth traversed by the main gamma-ray pulse rises above unity, and the pulse is broadened. These considerations place significant constraints on burst progenitors: a pre-burst mass loss rate exceeding 10^{-5} M_\\odot per year is difficult to reconcile with individual pulses narrower than 10 s, unless the radiative efficiency is low. An anisotropic gamma-ray flux (on an angular scale \\Gamma^{-1} or larger) drives a large velocity shear that greatly increases the energy in the seed magnetic field forward of the propagating shock.

Christopher Thompson; Piero Madau

2000-02-21T23:59:59.000Z

36

Influence of Spinning Electric Fields on Natural Background Gamma-Radiation  

E-Print Network [OSTI]

This paper considers influence of spinning electric field on statistics of natural background gamma-radiation. The spinning electric field, shown as a virtual gyroscope, has quantum mechanics characteristics. Interaction of the virtual fermion-like gyroscope with bosons (gamma-quanta) results in lowering intensity of the gamma-radiation and altering Poisson distribution. The statistic of the observed phenomenon depends on the direction of rotation of the virtual gyroscope. The results are discussed in a shade of spin-spin interaction having regard to realizing thermodynamically profitable conditions. Similarity of observed reduction of gamma-radiation in spinning electric fields and that for mechanical rotation stresses a special role of rotation itself, disregarding the matter of its carrier.

Mark Krinker; Felix Kitaichik

2010-04-28T23:59:59.000Z

37

GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION  

SciTech Connect (OSTI)

The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

Turick, C.; Ekechukwu, A.; Milliken, C.

2011-05-17T23:59:59.000Z

38

Low Level Gamma Spectroscopy Measurements of Radium and Cesium in Lucerne (Medicago Sativa)  

SciTech Connect (OSTI)

Nineteen years after Chernobyl nuclear accident, activity concentration of 137Cs still could be detected in food and soil samples in Central and Eastern Europe. In this paper radiation levels of radium and cesium in Lucerne will be presented. It is a perennial plant with a deep root system and it is widely grown throughout the world as forage for cattle. The samples of Lucerne were taken from twelve different locations in Vojvodina in the summer period July-September 2004. The samples were specially dried on the air and after that ground, powdered and mineralized by method of dry burning on the temperature of 450 deg. C. Gamma spectrometry measurements of the ash were performed by means of actively shielded germanium detector with maximal background reduction. For cesium 137Cs 10 mBq/kg order of magnitude detection limits were achieved.

Fokapic, S.; Bikit, I.; Mrda, D.; Veskovic, M.; Slivka, J. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 4, 21 000 Novi Sad (Serbia); Mihaljev, Z. [Scientific Veterinary Institute, Rumenacki put 20, 21 000 Novi Sad (Serbia); Cupic, Z. [Research Institute for Reproduction, A.I. and Embryo Transfer Temerin, 21235 Temerin, Industrijska zona bb. (Serbia)

2007-04-23T23:59:59.000Z

39

Reflectivity of linear and nonlinear gamma radiated apodized chirped Bragg grating under ocean  

SciTech Connect (OSTI)

In this paper, the effect Co{sup 60} gamma radiation is investigated on the effective refractive index of apodized chirped Bragg grating. Nine apodization profiles are considered. Comparison between the reflectivity of the gamma radiated and non radiated fiber Bragg grating has been carried out. The electric field of signals propagating through the apodized chirped fiber Bragg grating (ACFBG) is first calculated from which, new values for the refractive index are determined. The nonlinear effects appear on the ACFBG reflectivity. The effect of nonlinearity and undersea temperature and pressure on the grating is also studied.

Hamdalla, Taymour A. [Faculty of Science, Alexandria University, Alexandria (Egypt); Faculty of Science, Tabuk University, Tabuk (Saudi Arabia)

2012-09-06T23:59:59.000Z

40

Indoor and Outdoor in Situ High-Resolution Gamma Radiation Measurements in Urban Areas of Cyprus  

E-Print Network [OSTI]

In situ, high-resolution, gamma-ray spectrometry of a total number of 70 outdoor and 20 indoor representative measurements were performed in preselected, common locations of the main urban areas of Cyprus. Specific activities and gamma absorbed dose rates in air due to the naturally occurring radionuclides of Th-232 and U-238 series, and K-40 are determined and discussed. Effective dose rate to the Cyprus population due to terrestrial gamma radiation is derived directly from this work. The results obtained outdoors match very well with those derived previously by high-resolution gamma spectrometry of soil samples, which were collected from the main island bedrock surface. This implies that the construction and building materials in urban areas do not affect the external gamma dose rate; thus they are mostly of local origin. Finally, the indoor/outdoor gamma dose ratio was found to be 1.4 +- 0.5.

Svoukis, E

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Indoor and Outdoor in Situ High-Resolution Gamma Radiation Measurements in Urban Areas of Cyprus  

E-Print Network [OSTI]

In situ, high-resolution, gamma-ray spectrometry of a total number of 70 outdoor and 20 indoor representative measurements were performed in preselected, common locations of the main urban areas of Cyprus. Specific activities and gamma absorbed dose rates in air due to the naturally occurring radionuclides of Th-232 and U-238 series, and K-40 are determined and discussed. Effective dose rate to the Cyprus population due to terrestrial gamma radiation is derived directly from this work. The results obtained outdoors match very well with those derived previously by high-resolution gamma spectrometry of soil samples, which were collected from the main island bedrock surface. This implies that the construction and building materials in urban areas do not affect the external gamma dose rate; thus they are mostly of local origin. Finally, the indoor/outdoor gamma dose ratio was found to be 1.4 +- 0.5.

E. Svoukis; H. Tsertos

2006-10-02T23:59:59.000Z

42

Automotive Component Measurements forAutomotive Component Measurements for Determining VehicleDetermining Vehicle--Level RadiatedLevel Radiated  

E-Print Network [OSTI]

1 Automotive Component Measurements forAutomotive Component Measurements for Determining VehicleDetermining Vehicle--Level RadiatedLevel Radiated Automotive Component Measurements forAutomotive Component automotiveWe need to characterize automotive components the way we characterize circuitcomponents the way we

Stuart, Steven J.

43

What is the radiative process of the prompt phase of Gamma Ray Bursts?  

SciTech Connect (OSTI)

Despite the dramatic improvement of our knowledge of the phenomenology of Gamma Ray Bursts, we still do not know several fundamental aspects of their physics. One of the puzzles concerns the nature of the radiative process originating the prompt phase radiation. Although the synchrotron process qualifies itself as a natural candidate, it faces severe problems, and many efforts have been done looking for alternatives. These, however, suffer from other problems, and there is no general consensus yet on a specific radiation mechanism.

Ghisellini, G. [INAF-Osservatorio Astronomico di Brera, Via Bianchi 46 I-23807 Merate (Italy)

2010-07-15T23:59:59.000Z

44

Influence of relaxation transitions on radiation-initiated cationic graft polymerization. [Gamma radiation  

SciTech Connect (OSTI)

Radiation grafting of vinyl n-butyl ether (VBE) to polyvinyl chloride (PVC) over a broad temperature range was investigated. The relaxation transitions in the PVC/VBE system were also determined. Grafting of vinyl alkyl ethers proceeds entirely by a cationic mechanism in a reaction medium that has been dried to a water concentration no greater than 0.1-1.0 ppm. In this connection, the diffusion properties of water in the temperature region were studied. Commercial films of unplasticized PVC (thickness 200 M); were subjected to swelling in two systems: in a 50% solution of VBE in benzene at 25/sup 0/C, and in the pure monomer at 40/sup 0/C. The reaction mixtures were first dried over metallic sodium in a deaerated atmosphere. The specimens were irradiated in a Co gamma-radiation unit to a dose of 10 kGy at a dose rate of 3 Gy/sec. The first reaction mixture was investigated over a range of temperatures from -60/sup 0/ to +70/sup 0/C, and the second from -15/sup 0/ to +50/sup 0/C. The degree of grafting was determined from the increase in weight of the original ungrafted film. The temperature was held to within +/-1/sup 0/C. The relaxation transitions in the swollen polymer systems were determined by two methods, thermostimulated current (TSC) and thermomechanics (TM). It was found that in the region of the glass transition of a swollen PVC-VBE system, radiation-initiated cationic graft polymerization proceeds at a maximal rate, and there are changes in state of the water molecules (the agents of breaking the ion reaction chain) and in their diffusion properties within the matrix.

Kudryavtsev, V.N.; Kabanov, V.Ya.; Chalykh, A.E.; Spitsyn, V.I.

1982-05-01T23:59:59.000Z

45

Radiation levels on empty cylinders containing heel material  

SciTech Connect (OSTI)

Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

Shockley, C.W. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31T23:59:59.000Z

46

Estimating GroundEstimating Ground--Level Solar RadiationLevel Solar Radiation and Evapotranspiration In Puerto Ricoand Evapotranspiration In Puerto Rico  

E-Print Network [OSTI]

Estimating GroundEstimating Ground--Level Solar RadiationLevel Solar Radiation radiation, therefore, solar radiation measurements throughout the island are essential. #12;Currently, including solar radiation ·In PR, solar radiation is only available at selected locations. · The majority

Gilbes, Fernando

47

Radiation from Small-Scale Magnetic Field Turbulence: Implications for Gamma-Ray Bursts and Laboratory Astrophysical Plasmas  

E-Print Network [OSTI]

a region of current filamentation, and show that the jitter radiation may be used as a radiative diagnostic to determine features of the magnetic field distribution within this region. For gamma-ray bursts, this instability may play a significant...

Reynolds, Sarah J

2012-05-31T23:59:59.000Z

48

Operating Experience Level 3, DOE Occupational Radiation Exposures for 2013  

Broader source: Energy.gov [DOE]

This Operating Experience Level 3 (OE-3) document provides an overview summary of radiation doses from occupational exposures at the Department of Energy (DOE), including the National Nuclear Security Administration for the year 2013.

49

Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system  

DOE Patents [OSTI]

A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

2013-02-12T23:59:59.000Z

50

Effective gamma-ray doses due to natural radiation from soils of southeastern Brazil  

SciTech Connect (OSTI)

We have used gamma-ray spectrometry to study the distribution of natural radiation from soils of southeastern Brazil: Billings reservoir, Sao Bernardo do Campo Parks, Diadema Parks, Interlagos region, Sao Paulo, and soil from Sao Paulo and Rio de Janeiro beaches. In most of the regions studied we have found that the dose due the external exposure to gamma-rays, proceeding from natural terrestrial elements, are between the values 0.3 and 0.6 mSv/year, established by the United Nations Scientific Committee on the Effects of Atomic Radiation.

Silveira, M. A. G.; Moreira, R. H.; Bellini, B. S. [Centro Universitario da FEI, Sao Bernardo do Campo, Sao Paulo (Brazil); Medina, N. H.; Aguiar, V. A. P. [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

2010-08-04T23:59:59.000Z

51

Network-level fallout radiation effects assessment. Final report  

SciTech Connect (OSTI)

National Security calls for the ability to maintain communication capabilities in times of national disaster, which could include a nuclear attack. Nuclear detonation has two basic by-products for which telecommunication equipments are susceptible to damage. These are electromagnetic pulse (EMP) and fallout radiation. The purposes of the EMP Mitigation Program are to analyze and to lessen the effects of EMP and fallout radiation on national telecommunications resources. Fallout radiation occurs after the initial intense high-frequency EMP, and is the subject of this analysis. Fallout radiation is the residual radiation that remains in the atmosphere after a nuclear blast, and which can be carried by weather conditions to locations far from the detonation point. This analysis focuses on the effects of fallout radiation on the telecommunications network of the American Telephone and Telegraph Co. (AT and T). This assessment of AT and T-network's communications-capabilities uses a network-level approach to assess fallout-radiation effects on the network's performance. The approach used was developed for assessing network-level EMP effects on Public Switched Network communication capabilities. Details are given on how EMP assessments utilize this method. Equipment-level fallout-radiation survivability data is also required.

Not Available

1991-05-01T23:59:59.000Z

52

Radiation detection system for portable gamma-ray spectroscopy  

DOE Patents [OSTI]

A portable gamma ray detection apparatus having a gamma ray detector encapsulated by a compact isolation structure having at least two volumetrically-nested enclosures where at least one is a thermal shield. The enclosures are suspension-mounted to each other to successively encapsulate the detector without structural penetrations through the thermal shields. A low power cooler is also provided capable of cooling the detector to cryogenic temperatures without consuming cryogens, due to the heat load reduction by the isolation structure and the reduction in the power requirements of the cooler. The apparatus also includes a lightweight portable power source for supplying power to the apparatus, including to the cooler and the processing means, and reducing the weight of the apparatus to enable handheld operation or toting on a user's person.

Rowland, Mark S. (Alamo, CA); Howard, Douglas E. (Livermore, CA); Wong, James L. (Dublin, CA); Jessup, James L. (Tracy, CA); Bianchini, Greg M. (Livermore, CA); Miller, Wayne O. (Livermore, CA)

2006-06-20T23:59:59.000Z

53

Microbiological, chemical, and sensory quality changes in Pico de gallo as affected by gamma radiation  

E-Print Network [OSTI]

This study was undertaken to gain a greater understanding of the effects of gamma radiation and storage at 2'C on the microbiological, sensorial and chemical quality of pico de gallo. Samples of pico de gallo were exposed to cobalt'o at a dose of I...

Miller, Gerald Howard

1994-01-01T23:59:59.000Z

54

THE PHOTOSPHERIC RADIATION MODEL FOR THE PROMPT EMISSION OF GAMMA-RAY BURSTS: INTERPRETING FOUR OBSERVED CORRELATIONS  

SciTech Connect (OSTI)

We show that the empirical E{sub p}-L, {Gamma}-L, E{sub p}-{Gamma}, and {eta}-bar{sub {gamma}}-E{sub p} correlations (where L is the time-averaged luminosity of the prompt emission, E{sub p} is the spectral peak energy, {Gamma} is the bulk Lorentz factor, and {eta}-bar{sub {gamma}} is the emission efficiency of gamma-ray bursts, GRBs) are well consistent with the relations between the analogous parameters predicted in the photospheric radiation model of the prompt emission of GRBs. The time-resolved thermal radiation of GRB 090902B does follow the E{sub p}-L and {Gamma}-L correlations. A reliable interpretation of the four correlations in alternative models is still lacking. These may point toward a photospheric origin of prompt emission of some GRBs.

Fan Yizhong; Wei Daming; Zhang Fuwen [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang Binbin, E-mail: yzfan@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn, E-mail: fwzhang@pmo.ac.cn, E-mail: bbzhang@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

2012-08-10T23:59:59.000Z

55

Observation of the radiative decay D*+-> D+gamma  

E-Print Network [OSTI]

, Livermore, CA 94551. ? Permanent address: BINP, RU-630090 Novosibirsk, Russia. 107 Permanent address: Yonsei University, Seoul 120-749, Korea. [1] See, for example, A.N. Kamal and Q.P. Xu, Phys. Lett. B 284, 421 (1992); P.J. O?Donnell and Q.P. Xu, Phys. Lett...VOLUME 80, NUMBER 18 PHYSICAL REVIEW LETTERS 4MAY 1998 Observation of the Radiative Decay D p1 !D 1 g J. Bartelt, 1 S.E. Csorna, 1 V. Jain, 1, * K.W. McLean, 1 S. Marka, 1 R. Godang, 2 K. Kinoshita, 2 I.C. Lai, 2 P. Pomianowski, 2 S. Schrenk, 21 G...

Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Darling, C.; Davis, Robin E. P.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan; Zhou, L.

1998-05-01T23:59:59.000Z

56

Gamma Radiation Effects on Physical, Optical, and Structural Properties of  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun with Big Sky Learning Fun with Big SkyDIII-DRMRGamma Radiation and X-Rays

57

High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation  

DOE Patents [OSTI]

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

1987-02-27T23:59:59.000Z

58

Beta decay radiation signature from neutron-rich gamma-ray bursts?  

E-Print Network [OSTI]

Core collapse of massive stars and binary neutron stars or black hole-neutron star binary mergers are likely progenitors of long and short duration gamma-ray bursts respectively. Neutronized material in the former and neutron star material in the latter are ejected by the central engine implying a neutron-rich jet outflow. A free neutron, however, beta decays to a proton, an electron (beta) and an anti-neutrino in about fifteen minutes in its rest frame. Sudden creation of a relativistic electron is accompanied by radiation with unique temporal and spectral signature. We calculate here this radiation signature collectively emitted by all beta decay electrons from neutron-rich outflow. Detection of this signature may thus provide strong evidence for not only neutron but also for proton content in the relativistic gamma-ray burst jets.

Soebur Razzaque; Peter Meszaros

2006-06-09T23:59:59.000Z

59

PHOTOSPHERIC EMISSION AS THE DOMINANT RADIATION MECHANISM IN LONG-DURATION GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

We present the results of a set of numerical simulations of long-duration gamma-ray burst jets associated with massive, compact stellar progenitors. The simulations extend to large radii and allow us to locate the region in which the peak frequency of the advected radiation is set before the radiation is released at the photosphere. Light curves and spectra are calculated for different viewing angles as well as different progenitor structures and jet properties. We find that the radiation released at the photosphere of matter-dominated jets is able to reproduce the observed Amati and energy-Lorentz factor correlations. Our simulations also predict a correlation between the burst energy and the radiative efficiency of the prompt phase, consistent with observations.

Lazzati, Davide [Department of Physics, NC State University, 2401 Stinson Drive, Raleigh, NC 27695-8202 (United States); Morsony, Brian J. [Department of Astronomy, University of Wisconsin-Madison, 3321 Sterling Hall, 475 N. Charter Street, Madison WI 53706-1582 (United States); Margutti, Raffaella [Harvard-Smithsonian Center for Astrophysics, ITC, 60 Garden Street, Cambridge, MA 02138 (United States); Begelman, Mitchell C. [JILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309-0440 (United States)

2013-03-10T23:59:59.000Z

60

Equipment level fallout radiation-effects approach. Final report  

SciTech Connect (OSTI)

National Security Decision Directive (NSDD) 97 and Executive Order (EO) 12472 call for the ability to maintain National Security Emergency Preparedness (NSEP) communication capabilities in times of national disaster, which includes a nuclear attack. The Office of the Manager, National Communications System (OMNCS) sponsors the Electromagnetic Pulse (EMP) Mitigation Program to evaluate and, where possible, mitigate the effects of the nuclear attack. Fallout radiation has been identified as an environment that may effect the performance of the regional and national telecommunication system. This report presents the investigations in the network-level fallout radiation methodology used to determine the effects of this environment. Alternative techniques are presented to improve the methodology.

Not Available

1989-02-10T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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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61

Method for detecting water equivalent of snow using secondary cosmic gamma radiation  

DOE Patents [OSTI]

Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attentuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power.

Condreva, Kenneth J. (1420 Fifth St., Livermore, Alameda County, CA 94550)

1997-01-01T23:59:59.000Z

62

Method for detecting water equivalent of snow using secondary cosmic gamma radiation  

DOE Patents [OSTI]

Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attenuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power. 4 figs.

Condreva, K.J.

1997-01-14T23:59:59.000Z

63

Gamma ray bursts may be blueshifted bundles of the relic radiation  

E-Print Network [OSTI]

A hypothesis is proposed that the gamma-ray bursts (GRBs) may arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The blueshift mechanism is provided by such a Lema\\^{\\i}tre -- Tolman (L--T) model, in which the bang-time function $t_B(r)$ is not everywhere constant. Blueshift arises on \\textit{radial} rays that are emitted over regions where $\\dril{t_B} r \

Krasi?ski, Andrzej

2015-01-01T23:59:59.000Z

64

Gamma ray bursts may be blueshifted bundles of the relic radiation  

E-Print Network [OSTI]

A hypothesis is proposed that the gamma-ray bursts (GRBs) may arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The blueshift mechanism is provided by such a Lema\\^{\\i}tre -- Tolman (L--T) model, in which the bang-time function $t_B(r)$ is not everywhere constant. Blueshift arises on \\textit{radial} rays that are emitted over regions where $\\dril{t_B} r \

Andrzej Krasi?ski

2015-02-02T23:59:59.000Z

65

Methyl viologen radical reactions with several oxidizing agents. [Gamma Radiation  

SciTech Connect (OSTI)

The rates of oxidation of the methyl viologen radical by peroxodisulfate and hydrogen peroxide has been investigated. The methyl viologen free radical was produced by pulse radiolysis. The reaction of the peroxodisulfate radical with the methyl viologen radical was first order in both species, and the reaction rate constant is reported. A el-radiation study revealed a chain decomposition of the peroxodisulfate radical involving the methyl viologen radical when methanol, ethanol, or 2-propanol was present. Loss of the methyl viologen radical was then no longer observed to be a simple first-order reaction. The reaction of hydrogen peroxide with the methyl viologen radical was very slow in the presence of 1 M methanol. A much faster reaction in the absence of methanol was interpreted to be a reaction of the methyl viologen radical with the peroxy radicals. Hydrogen peroxide, in contrast to the chain decomposition of peroxodisulfate radicals, does not participate in a chain reaction involving the methyl viologen radical and methanol. Rate constants for the reaction of methyl viologen radical with dichromate radical, iodate radical, and ferricyanide radical are reported.

Levey, G.; Ebbesen, T.W.

1983-01-01T23:59:59.000Z

66

Reduction of Quark Mass Scheme Dependence in B bar -> Xs gamma at the NNLL Level  

SciTech Connect (OSTI)

The uncertainty of the theoretical prediction of the B {yields} X{sub s}{gamma} branching ratio at NLL level is dominated by the charm mass renormalization scheme ambiguity. In this paper we calculate those NNLL terms which are related to the renormalization of m{sub c}, in order to get an estimate of the corresponding uncertainty at the NNLL level. We find that these terms significantly reduce (by typically a factor of two) the error on BR(B {yields} X{sub s}{gamma}) induced by the definition of m{sub c}. Taking into account the experimental accuracy of around 10% and the future prospects of the B factories, we conclude that a NNLL calculation would increase the sensitivity of the observable B {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM significantly.

Asatrian, H.M.; /Yerevan Phys. Inst.; Greub, C.; /Bern U.; Hovhannisyan, A.; /Yerevan Phys. Inst.; Hurth, T.; /CERN /SLAC; Poghosyan, V.; /Yerevan Phys. Inst.

2005-06-20T23:59:59.000Z

67

Gamma-thermometer-based reactor-core liquid-level detector. [PWR  

SciTech Connect (OSTI)

A system is provided which employs a modified gamma thermometer for determining the liquid coolant level within a nuclear reactor core. The gamma thermometer which normally is employed to monitor local core heat generation rate (reactor power), is modified by thermocouple junctions and leads to obtain an unambiguous indication of the presence or absence of coolant liquid at the gamma thermometer location. A signal processor generates a signal based on the thermometer surface heat transfer coefficient by comparing the signals from the thermocouples at the thermometer location. The generated signal is a direct indication of loss of coolant due to the change in surface heat transfer when coolant liquid drops below the thermometer location. The loss of coolant indication is independent of reactor power at the thermometer location. Further, the same thermometer may still be used for the normal power monitoring function.

Burns, T.J.

1981-06-16T23:59:59.000Z

68

Determination of the Dark Matter profile from the EGRET excess of diffuse Galactic gamma radiation  

E-Print Network [OSTI]

The excess above 1 GeV in the energy spectrum of the diffuse Galactic gamma radiation, measured with the EGRET experiment, can be interpreted as the annihilation of Dark Matter (DM) particles. The DM is distributed in a halo around the Milky Way. Considering the directionality of the gamma ray flux it is possible to determine the halo profile. The DM within the halo has a smooth and a clumpy component.These components can have different profiles as suggested by N-body simulations and the data is indeed compatible with a NFW profile for the diffuse component and a cored profile for the clumpy component.These DM clumps can be partly destroyed by tidal forces from interactions with stars and the gravitational potential of the Galactic disc.This effect mainly decreases the annihilation signal from the Galactic centre (GC). In this paper constraints on the different profiles and the survival probability of the clumps are discussed.

Markus Weber

2007-10-26T23:59:59.000Z

69

Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector  

E-Print Network [OSTI]

Spectroscopic measurements are presented using the PID350 pixelated gamma radiation detectors. A high-speed data acquisition system has been developed in order to reduce the data loss during the data reading in case of a high flux of photons. A data analysis framework has been developed in order to improve the resolution of the acquired energy spectra, using specific calibration parameters for each PID350's pixel. Three PID350 detectors have been used to construct a stacked prototype system and spectroscopic measurements have been performed in order to test the ability of the prototype to localize radioactive sources.

Karafasoulis, K; Seferlis, S; Papadakis, I; Loukas, D; Lambropoulos, C; Potiriadis, C

2010-01-01T23:59:59.000Z

70

Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector  

E-Print Network [OSTI]

Spectroscopic measurements are presented using the PID350 pixelated gamma radiation detectors. A high-speed data acquisition system has been developed in order to reduce the data loss during the data reading in case of a high flux of photons. A data analysis framework has been developed in order to improve the resolution of the acquired energy spectra, using specific calibration parameters for each PID350's pixel. Three PID350 detectors have been used to construct a stacked prototype system and spectroscopic measurements have been performed in order to test the ability of the prototype to localize radioactive sources.

K. Karafasoulis; K. Zachariadou; S. Seferlis; I. Papadakis; D. Loukas; C. Lambropoulos; C. Potiriadis

2010-11-15T23:59:59.000Z

71

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

SciTech Connect (OSTI)

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

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

1981-11-01T23:59:59.000Z

72

Gamma watermarking  

DOE Patents [OSTI]

A covert, gamma-ray "signature" is used as a "watermark" for property identification. This new watermarking technology is based on a unique steganographic or "hidden writing" digital signature, implemented in tiny quantities of gamma-ray-emitting radioisotopic material combinations, generally covertly emplaced on or within an object. This digital signature may be readily recovered at distant future times, by placing a sensitive, high energy-resolution gamma-ray detecting instrument reasonably precisely over the location of the watermark, which location may be known only to the object's owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background (including the gamma radiation naturally emanating from the object itself, from cosmic radiation and material surroundings, from human bodies, etc.). The "watermark" is used in object-tagging for establishing object identity, history or ownership. It thus may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft thereof. Highly effective, potentially very low cost identification-on demand of items of most all types is thus made possible.

Ishikawa, Muriel Y.; Wood, Lowell L.; Lougheed, Ronald W.; Moody, Kenton J.; Wang, Tzu-Fang

2004-05-25T23:59:59.000Z

73

Cold neutron prompt gamma activation analysis, a non-destructive technique for hydrogen level assessment in zirconium alloys  

E-Print Network [OSTI]

embrittlement by decreasing overall corrosion and/or by decreasing the amount of hydrogen ingress for a givenCold neutron prompt gamma activation analysis, a non-destructive technique for hydrogen level to quantitatively assess hydrogen concentration in zirconium alloys. The technique, called Cold Neutron Prompt Gamma

Motta, Arthur T.

74

Relativistic Winds from Compact Gamma-ray Sources: I. Radiative Acceleration in the Klein-Nishina Regime  

E-Print Network [OSTI]

We consider the radiative acceleration to relativistic bulk velocities of a cold, optically thin plasma which is exposed to an external source of gamma-rays. The flow is driven by radiative momentum input to the gas, the accelerating force being due to Compton scattering in the relativistic Klein-Nishina limit. The bulk Lorentz factor of the plasma, Gamma, derived as a function of distance from the radiating source, is compared with the corresponding result in the Thomson limit. Depending on the geometry and spectrum of the radiation field, we find that particles are accelerated to the asymptotic Lorentz factor at infinity much more rapidly in the relativistic regime; and the radiation drag is reduced as blueshifted, aberrated photons experience a decreased relativistic cross section and scatter preferentially in the forward direction. The random energy imparted to the plasma by gamma-rays can be converted into bulk motion if the hot particles execute many Larmor orbits before cooling. This `Compton afterburn' may be a supplementary source of momentum if energetic leptons are injected by pair creation, but can be neglected in the case of pure Klein-Nishina scattering. Compton drag by side-scattered radiation is shown to be more important in limiting the bulk Lorentz factor than the finite inertia of the accelerating medium. The processes discussed here may be relevant to a variety of astrophysical situations where luminous compact sources of hard X- and gamma-ray photons are observed, including active galactic nuclei, galactic black hole candidates, and gamma-ray bursts.

Piero Madau; Christopher Thompson

1999-11-30T23:59:59.000Z

75

Gamma radiation-induced refractive index change in Ge- and N-doped silica  

SciTech Connect (OSTI)

We measured the change of the refractive index over a wide wavelength range in Ge- and N-doped high purity (fiber optics grade) silica glasses subjected to gamma irradiation. The radiation-induced change of the refractive index tends to be greater in the infrared part of the spectrum compare to the values measured in the UV-visible part of the spectrum. By means of the Kramers-Kronig relations, we estimate that a weak broadening of the optical vibration band of the silica network adds to this effect. The paper also discusses the difference observed in the spectral behavior of the induced refractive index change for both types of doped glass.

Brichard, Benoit [SCK-CEN-Belgian Nuclear Research Center, Boeretang 200, 2400 Mol (Belgium); Butov, Oleg V.; Golant, Konstantin M. [Fiber Optics Research Center, Russian Academy of Sciences, Vavilov Street 38, 119991 Moscow (Russian Federation); Fernandez Fernandez, Alberto [Masterminds Ltd., rue du Temple 40, CH-2800 Delemont (Switzerland)

2008-03-01T23:59:59.000Z

76

FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)  

SciTech Connect (OSTI)

We describe progress in the development of new materials for portable, room-temperature, gamma-radiation detection at Pacific Northwest National Laboratory at the Hanford Site in Washington State. High Z, high resistivity, amorphous semiconductors are being designed for use as solid-state detectors at near ambient temperatures; principles of operation are analogous to single-crystal semiconducting detectors. Amorphous semiconductors have both advantages and disadvantages compared to single crystals, and this project is developing methods to mitigate technical problems and design optimized material for gamma detection. Several issues involved in the fabrication of amorphous semiconductors are described, including reaction thermodynamics and kinetics, the development of pyrolytic coating, and the synthesis of ingots. The characterization of amorphous semiconductors is described, including sectioning and polishing protocols, optical microscopy, X-ray diffraction, scanning electron microscopy, optical spectroscopy, particle-induced X-ram emission, Rutherford backscattering, and electrical testing. Then collaboration with the University of Illinois at Urbana-Champaign is discussed in the areas of Hall-effect measurements and current voltage data. Finally, we discuss the strategy for continuing the program.

Johnson, Bradley R.; Riley, Brian J.; Crum, Jarrod V.; Sundaram, S. K.; Henager, Charles H.; Zhang, Yanwen; Shutthanandan, V.

2007-01-01T23:59:59.000Z

77

Very High Energy Gamma Rays from Supernova Remnants and Constraints on the Galactic Interstellar Radiation Field  

SciTech Connect (OSTI)

The large-scale Galactic interstellar radiation field (ISRF) is the result of stellar emission and dust re-processing of starlight. Where the energy density of the ISRF is high (e.g., the Galactic Centre), the dominant {gamma}-ray emission in individual supernova remnants (SNRs), such as G0.9+0.1, may come from inverse Compton (IC) scattering of the ISRF. Several models of the ISRF exist. The most recent one, which has been calculated by us, predicts a significantly higher ISRF than the well used model of Mathis, Mezger, and Panagia [1]. However, comparison with data is limited to local observations. Based on our current estimate of the ISRF we predict the gamma-ray emission in the SNRs G0.9+0.1 and RXJ1713, and pair-production absorption features above 20 TeV in the spectra of G0.9+0.1, J1713-381, and J1634-472. We discuss how GLAST, along with current and future very high energy instruments, may be able to provide upper bounds on the large-scale ISRF.

Porter, T.A.; Moskalenko, I.V.; Strong, A.W.

2007-04-30T23:59:59.000Z

78

Very High Energy Gamma Rays from Supernova Remnants and Constraints on the Galactic Interstellar Radiation Field  

E-Print Network [OSTI]

The large-scale Galactic interstellar radiation field (ISRF) is the result of stellar emission and dust re-processing of starlight. Where the energy density of the ISRF is high (e.g., the Galactic Centre), the dominant gamma-ray emission in individual supernova remnants (SNRs), such as G0.9+0.1, may come from inverse Compton (IC) scattering of the ISRF. Several models of the ISRF exist. The most recent one, which has been calculated by us, predicts a significantly higher ISRF than the well-used model of Mathis, Mezger, and Panagia. However,comparison with data is limited to local observations. Based on our current estimate of the ISRF we predict the gamma-ray emission in the SNRs G0.9+0.1 and RXJ1713, and pair-production absorption features above 20 TeV in the spectra of G0.9+0.1, J1713-381, and J1634-472. We discuss how GLAST, along with current and future very high energy instruments, may be able to provide upper bounds on the large-scale ISRF.

Porter, T A; Strong, A W

2007-01-01T23:59:59.000Z

79

Very High Energy Gamma Rays from Supernova Remnants and Constraints on the Galactic Interstellar Radiation Field  

E-Print Network [OSTI]

The large-scale Galactic interstellar radiation field (ISRF) is the result of stellar emission and dust re-processing of starlight. Where the energy density of the ISRF is high (e.g., the Galactic Centre), the dominant gamma-ray emission in individual supernova remnants (SNRs), such as G0.9+0.1, may come from inverse Compton (IC) scattering of the ISRF. Several models of the ISRF exist. The most recent one, which has been calculated by us, predicts a significantly higher ISRF than the well-used model of Mathis, Mezger, and Panagia. However,comparison with data is limited to local observations. Based on our current estimate of the ISRF we predict the gamma-ray emission in the SNRs G0.9+0.1 and RXJ1713, and pair-production absorption features above 20 TeV in the spectra of G0.9+0.1, J1713-381, and J1634-472. We discuss how GLAST, along with current and future very high energy instruments, may be able to provide upper bounds on the large-scale ISRF.

T. A. Porter; I. V. Moskalenko; A. W. Strong

2007-04-13T23:59:59.000Z

80

Gamma bursts  

SciTech Connect (OSTI)

The origin of cosmic gamma bursts is discussed. Radiation thermalization in magnetic fields, spectral mechanisms, and charge separation and photon heating are discussed. (GHT)

Colgate, S.A.; Petschek, A.G.

1982-12-09T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Analysis of Gamma Radiation from a Radon Source: Indications of a Solar Influence  

E-Print Network [OSTI]

This article presents an analysis of about 29,000 measurements of gamma radiation associated with the decay of radon in a sealed container at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between 28 January 2007 and 10 May 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis reveals a number of periodicities, including two at approximately 11.2 year$^{-1}$ and 12.5 year$^{-1}$. We have previously found these oscillations in nuclear-decay data acquired at the Brookhaven National Laboratory (BNL) and at the Physikalisch-Technische Bundesanstalt (PTB), and we have suggested that these oscillations are attributable to some form of solar radiation that has its origin in the deep solar interior. A curious property of the GSI data is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. This may be a systematic effect but, if it is not, this property should help narrow the theoretical options for the mechanism responsible for decay-rate variability.

Peter A. Sturrock; Gideon Steinitz; Ephraim Fischbach; Daniel Javorsek, II; Jere H. Jenkins

2012-05-01T23:59:59.000Z

82

GRABGAM: A Gamma Analysis Code for Ultra-Low-Level HPGe SPECTRA  

SciTech Connect (OSTI)

The GRABGAM code has been developed for analysis of ultra-low-level HPGe gamma spectra. The code employs three different size filters for the peak search, where the largest filter provides best sensitivity for identifying low-level peaks and the smallest filter has the best resolution for distinguishing peaks within a multiplet. GRABGAM basically generates an integral probability F-function for each singlet or multiplet peak analysis, bypassing the usual peak fitting analysis for a differential f-function probability model. Because F is defined by the peak data, statistical limitations for peak fitting are avoided; however, the F-function does provide generic values for peak centroid, full width at half maximum, and tail that are consistent with a Gaussian formalism. GRABGAM has successfully analyzed over 10,000 customer samples, and it interfaces with a variety of supplementary codes for deriving detector efficiencies, backgrounds, and quality checks.

Winn, W.G.

1999-07-28T23:59:59.000Z

83

The influence of {gamma}-ray radiation on electrical properties of CuGaSe{sub 2}  

SciTech Connect (OSTI)

The effect of {gamma}-ray radiation on the conductivity of low-resistivity (10{sup 2}2-10{sup 4} {Omega} cm) and high-resistivity (10{sup 5}-10{sup 7} {Omega} cm) CuGaSe{sub 2} single crystals has been studied in the temperature range 77-330 K. It is found that the resistivity of low-resistivity samples increases as the dose of {gamma}-ray radiation is increased, while the resistivity of high-resistivity samples is practically independent of the radiation dose. It is assumed that a decrease in the conductivity of the low-resistivity samples occurs owing to scattering of free charge carriers at defects (charged centers) formed as a result of irradiation with {gamma}-ray photons. It is found that the dose of the {gamma}-ray irradiation does not affect the temperature dependence of resistivity in the low- and high-resistivity samples in the temperature range 77-300 K.

Kasumoglu, I.; Kerimova, T. G., E-mail: ktaira@physics.ab.az; Mamedova, I. A. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)

2011-01-15T23:59:59.000Z

84

Detection of embedded radiation sources using temporal variation of gamma spectral data.  

SciTech Connect (OSTI)

Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the isotopes present in a measurement. For low energy resolution detectors, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the isotopes present in the measurement. When many isotopes are present it is difficult to make the correct identification and this process often requires many trial solutions by highly skilled spectroscopists. This report investigates the potential of a new analysis method which uses spatial/temporal information from multiple low energy resolution measurements to test the hypothesis of the presence of a target spectrum of interest in these measurements without the need to identify all the other isotopes present. This method is referred to as targeted principal component analysis (TPCA). For radiation portal monitor applications, multiple measurements of gamma spectra are taken at equally spaced time increments as a vehicle passes through the portal and the TPCA method is directly applicable to this type of measurement. In this report we describe the method and investigate its application to the problem of detection of a radioactive localized source that is embedded in a distributed source in the presence of an ambient background. Examples using simulated spectral measurements indicate that this method works very well and has the potential for automated analysis for RPM applications. This method is also expected to work well for isotopic detection in the presence of spectrally and spatially varying backgrounds as a result of vehicle-induced background suppression. Further work is needed to include effects of shielding, to understand detection limits, setting of thresholds, and to estimate false positive probability.

Shokair, Isaac R.

2011-09-01T23:59:59.000Z

85

E-Print Network 3.0 - area gamma radiation Sample Search Results  

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

POWER LAW SPECTRA OF GAMMARAY BURSTS Summary: SMOOTHLY BROKEN POWER LAW SPECTRA OF GAMMA-RAY BURSTS F. Ryde Stockholm Observatory, SE-133 36... . It is used to fit Gamma-Ray Burst...

86

High performance gamma measurements of equipment retrieved from Hanford high-level nuclear waste tanks  

SciTech Connect (OSTI)

The cleanup of high level defense nuclear waste at the Hanford site presents several progressive challenges. Among these is the removal and disposal of various components from buried active waste tanks to allow new equipment insertion or hazards mitigation. A unique automated retrieval system at the tank provides for retrieval, high pressure washing, inventory measurement, and containment for disposal. Key to the inventory measurement is a three detector HPGe high performance gamma spectroscopy system capable of recovering data at up to 90% saturation (200,000 counts per second). Data recovery is based on a unique embedded electronic pulser and specialized software to report the inventory. Each of the detectors have different shielding specified through Monte Carlo simulation with the MCNP program. This shielding provides performance over a dynamic range of eight orders of magnitude. System description, calibration issues and operational experiences are discussed.

Troyer, G.L.

1997-03-17T23:59:59.000Z

87

ME 361F Radiation and Radiation Protection Laboratory ABET EC2000 syllabus  

E-Print Network [OSTI]

-Ray Spectrometry 5. Gamma Ray Shielding/Low Level Counting 6. Neutron Activation Analysis 7. Sodium Iodide Detector-Ray Attenuation · Low-Level Gamma Ray Spectrometry · Reactor Health Physics · Neutron Shielding · Sodium Iodide and laboratory topics include personnel monitoring, radiation detection systems, gamma-ray spectroscopy

Ben-Yakar, Adela

88

Energy resolution in semiconductor gamma radiation detectors using heterojunctions and methods of use and preparation thereof  

DOE Patents [OSTI]

In one embodiment, a system comprises a semiconductor gamma detector material and a hole blocking layer adjacent the gamma detector material, the hole blocking layer resisting passage of holes therethrough. In another embodiment, a system comprises a semiconductor gamma detector material, and an electron blocking layer adjacent the gamma detector material, the electron blocking layer resisting passage of electrons therethrough, wherein the electron blocking layer comprises undoped HgCdTe. In another embodiment, a method comprises forming a hole blocking layer adjacent a semiconductor gamma detector material, the hole blocking layer resisting passage of holes therethrough. Additional systems and methods are also presented.

Nikolic, Rebecca J.; Conway, Adam M.; Nelson, Art J.; Payne, Stephen A.

2012-09-04T23:59:59.000Z

89

Abstract--We have recently completed a large-area, coded-aperture, gamma-ray imager for use in searching for radiation  

E-Print Network [OSTI]

Abstract-- We have recently completed a large-area, coded- aperture, gamma-ray imager for use. The in- strument uses a rank-19, one-dimensional coded aperture to cast shadow patterns onto a 0.57 m2 Na sufficient radiation can reach a large gamma-ray detec- tor from a small source to make detection possible

Horn, Berthold K.P.

90

Tritium: a model for low level long-term ionizing radiation exposure  

SciTech Connect (OSTI)

The somatic, cytogenetic and genetic effects of single and chronic tritiated water (HTO) ingestion in mice was investigated. This study serves not only as an evaluation of tritium toxicity (TRITOX) but due to its design involving long-term low concentration ingestion of HTO may serve as a model for low level long-term ionizing radiation exposure in general. Long-term studies involved animals maintained on HTO at concentrations of 0.3 ..mu..Ci/ml, 1.0 ..mu..Ci/ml, 3.0 ..mu..Ci/ml or depth dose equivalent chronic external exposures to /sup 137/Cs gamma rays. Maintenance on 3.0 ..mu..Ci/ml resulted in no effect on growth, life-time shortening or bone marrow cellularity, but did result in a reduction of bone marrow stem cells, an increase in DLM's in second generation animals maintained on this regimen and cytogenetic effects as indicated by increased sister chromatid exchanges (SCE's) in bone marrow cells, increased chromosome aberrations in the regenerating liver and an increase in micronuclei in red blood cells. Biochemical and microdosimetry studies showed that animals placed on the HTO regimen reached tritium equilibrium in the body water in approximately 17 to 21 days with a more gradual increase in bound tritium. When animals maintained for 180 days on 3.0 ..mu..Ci/ml HTO were placed on a tap water regimen, the tritium level in tissue dropped from the equilibrium value of 2.02 ..mu..Ci/ml before withdrawal to 0.001 ..mu..Ci/ml at 28 days. 18 references.

Carsten, A.L.

1984-01-01T23:59:59.000Z

91

Solid low-level radioactive waste radiation stability studies  

E-Print Network [OSTI]

properties and condition; on the other, on the specific features of thermal and radiation influences on it (Spitsyn et al. 1983). For the average composition of the fission products going to wastes repositories, the mean energy of irradiation may vary from... to the container determines, in part, the life of the container. Cormsion studies of containers by solidified wastes has indicated no problem areas in limited measurements to date; however very long-term effects have not been evaluated. The useful life...

Williams, Arnold Andre?

1989-01-01T23:59:59.000Z

92

Gamma-Ray Signatures for State-Of-Health Analysis and Monitoring of Widely-Arrayed Radiation Portal Monitor Systems  

SciTech Connect (OSTI)

Pacific Northwest National Laboratory (PNNL) has deployed a large array of radiation portal monitors for the Department of Homeland Security U.S. Customs and Border Protection. These portal monitors scan incoming vehicles crossing the U.S. border and shipping containers leaving international ports for radioactive material via gamma-ray and neutron detection. Data produced and captured by these systems are recorded for every vehicle related to radiation signature, sensor/system status, and local background, as well as a host of other variables. Within the Radiation Portal Monitor Project at PNNL, state-of-health observation and analysis for the whole RPM system using these data to determine functionality and performance is being developed. (PIET-43741-TM-492)

Woodring, Mitchell L.; Ely, James H.; Angel, Linda K.; Wright, Ingrid H.; Eslinger, Melany A.; Pospical, A. Jill; Ellis, John E.

2008-05-15T23:59:59.000Z

93

The Observation of the Weak Radiative Hyperon Decay XI0 ---> Lambda0 pi0 gamma at KTeV/E799, Fermilab  

SciTech Connect (OSTI)

The large sample of {Xi}{sup 0} hyperons available at KTeV 799 provides an opportunity to search for the Weak Radiative Hyperon Decay {Xi}{sup 0} {yields} {Lambda}{sup 0}{pi}{sup 0}{gamma}. They present a branching fraction measurement of {Xi}{sup 0} {yields} {Lambda}{sup 0}{pi}{sup 0}{gamma} based on the E799-II experiment data-taking in 1999 at KTeV, Fermilab. They used the principal decay of {Xi}{sup 0} {yields} {Lambda}{sup 0}{pi}{sup 0} where {Lambda} decays to a proton and a {pi}{sup -} as the flux normalization mode. This is the first observation of this interesting decay mode. 4 candidate events are found in the data. The branching ratio at 90% confidence level has been measured to be (1.67{sub -0.80}{sup +1.45}(stat.) {+-} 0.50(syst.)) x 10{sup -5} or (1.67{sub -0.69}{sup +1.16}(stat.) {+-} 0.50(syst.)) x 10{sup -5} at 68.27% confidence level.

Ping, Huican

2005-01-01T23:59:59.000Z

94

Network-level fallout radiation-effects assessment. Final report  

SciTech Connect (OSTI)

The EMP Mitigation Program analyzes, and where feasible, lessens the degradation effects of EMP on national telecommunication resources. The program focuses on the resources of the public switched network (PSN) because the PSN comprises the largest, most diverse set of telecommunication assets in the United States and is the focus of National Security Emergency Preparedness (NSEP) telecommunication enhancement activities. Additionally, the majority of various organizations rely on the PSN to conduct their NSEP telecommunications responsibilities. Telecommunication equipment is most susceptible to high altitude EMP (HEMP) which occurs when a nuclear weapon is detonated at an altitude greater that 50 km above the earth's surface. In addition to studying the effects of EMP, the program has expanded to address the effects of fallout radiation and serve traffic congestion on the PSN.

Not Available

1989-05-12T23:59:59.000Z

95

Near-Core and In-Core Neutron Radiation Monitors for Real Time Neutron Flux Monitoring and Reactor Power Level Measurements  

SciTech Connect (OSTI)

MPFDs are a new class of detectors that utilize properties from existing radiation detector designs. A majority of these characteristics come from fission chamber designs. These include radiation hardness, gamma-ray background insensitivity, and large signal output.

Douglas S. McGregor; Marvin L. Adams; Igor Carron; Paul Nelson

2006-06-12T23:59:59.000Z

96

Projection of needs for gamma radiation sources and other radioisotopes and assessment of alternatives for providing radiation sources  

SciTech Connect (OSTI)

Pacific Northwest Laboratory reviewed the projected uses and demands for a variety of nuclear byproducts. Because the major large-scale near-term demand is for gamma irradiation sources, this report concentrates on the needs for gamma sources and evaluates the options for providing the needed material. Projections of possible growth in the irradiation treatment industry indicate that there will be a need for 180 to 320 MCi of /sup 60/Co (including /sup 137/Cs equivalent) in service in the year 2000. The largest current and projected use of gamma irradiation is for the sterilization of medical devices and disposable medical supplies. Currently, 40% of US disposable medical products are treated by irradiation, and within 10 years it is expected that 90% will be treated in this manner. Irradiation treatment of food for destruction of pathogens or parasites, disinfestation, or extension of allowable storage periods is estimated to require an active inventory of 75 MCi of /sup 60/Co-equivalent gamma source in about a decade. 90 refs., 7 figs., 25 tabs.

Ross, W.A.; Jensen, G.A.; Clark, L.L.; Eakin, D.E.; Jarrett, J.H.; Katayama, Y.B.; McKee, R.W.; Morgan, L.G.; Nealey, S.M.; Platt, A.M.; Tingey, G.L.

1989-06-01T23:59:59.000Z

97

Study of the radiative decay J/psi. -->. gamma. eta. pi. /sup +/. pi. /sup -/  

SciTech Connect (OSTI)

The Mark III collaboration has performed a high statistics study of the reaction J/psi ..-->.. ..gamma..eta..pi../sup +/..pi../sup -/, with two different final states of the eta, eta ..-->.. ..gamma gamma.. and eta ..-->.. ..pi../sup 0/..pi../sup +/..pi../sup -/. Both modes have a broad structure from 1.2 to 1.9 GeV/c/sup 2/ and two structures, which decay via delta/sup + -/..pi../sup - +/, delta/sup + -/ ..-->.. eta..pi../sup + -/, are identified at 1.28 and 1.39 GeV/c/sup 2/. No signal is observed in the iota(1440) signal region.

Becker, J.J.; Blaylock, G.T.; Bolton, T.; Brown, J.S.; Bunnell, K.O.; Burnett, T.H.; Cassell, R.E.; Coffman, D.; Cook, V.; Coward, D.H.

1987-02-01T23:59:59.000Z

98

E-Print Network 3.0 - accompanying gamma radiation Sample Search...  

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

in which they deliver... emission. This is often, but not always, accompanied by gamma ray emission. There are a few excited states... -9117 (734) 763-4540 fax kearfott@umich.edu...

99

On the conversion of blast wave energy into radiation in active galactic nuclei and gamma-ray bursts  

E-Print Network [OSTI]

It has been suggested that relativistic blast waves may power the jets of AGN and gamma-ray bursts (GRB). We address the important issue how the kinetic energy of collimated blast waves is converted into radiation. It is shown that swept-up ambient matter is quickly isotropised in the blast wave frame by a relativistic two-stream instability, which provides relativistic particles in the jet without invoking any acceleration process. The fate of the blast wave and the spectral evolution of the emission of the energetic particles is therefore solely determined by the initial conditions. We compare our model with existing multiwavelength data of AGN and find remarkable agreement.

Martin Pohl; Reinhard Schlickeiser

1999-11-24T23:59:59.000Z

100

Extending the response of the sum coincidence spectrometer to multiple gamma radiation cascades  

E-Print Network [OSTI]

). crystal of sodium iodide with the sample placed inside of it is used. For larger crystals there is less probability of part of the gamma-ray energy escaping. This method gives a high detection efficiency; however, the resolution of large crystals can... be limited by light collection problems. For precision gamma-ray spectroscopy, high resolution out-weighs the disadvantage of low detection efficiency. The three-crystal scintillation spectrometer, developed by Maieschein' and Bair5, gives higher counting...

Helton, Victor Dean

1964-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Observation of contemporaneous optical radiation from a gamma-ray burst  

E-Print Network [OSTI]

The origin of gamma-ray bursts (GRBs) has been enigmatic since their discovery. The situation improved dramatically in 1997, when the rapid availability of precise coordinates for the bursts allowed the detection of faint optical and radio afterglows - optical spectra thus obtained have demonstrated conclusively that the bursts occur at cosmological distances. But, despite efforts by several groups, optical detection has not hitherto been achieved during the brief duration of a burst. Here we report the detection of bright optical emission from GRB990123 while the burst was still in progress. Our observations begin 22 seconds after the onset of the burst and show an increase in brightness by a factor of 14 during the first 25 seconds; the brightness then declines by a factor of 100, at which point (700 seconds after the burst onset) it falls below our detection threshold. The redshift of this burst, approximately 1.6, implies a peak optical luminosity of 5 times 10^{49} erg per second. Optical emission from gamma-ray bursts has been generally thought to take place at the shock fronts generated by interaction of the primary energy source with the surrounding medium, where the gamma-rays might also be produced. The lack of a significant change in the gamma-ray light curve when the optical emission develops suggests that the gamma-rays are not produced at the shock front, but closer to the site of the original explosion.

C. Akerlof; R. Balsano; S. Barthelmy; J. Bloch; P. Butterworth; D. Casperson; T. Cline; S. Fletcher; F. Frontera; G. Gisler; J. Heise; J. Hills; R. Kehoe; B. Lee; S. Marshall; T. McKay; R. Miller; L. Piro; W. Priedhorsky; J. Szymanski; J. Wren

1999-03-17T23:59:59.000Z

102

FY08 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)  

SciTech Connect (OSTI)

This is the annual report for an old project funded by NA22. The purpose of the project was to develop amorphous semiconductors for use as radiation detectors. The annual report contains information about the progress made in synthesizing, characterizing, and radiation response testing of these new materials.

Johnson, Bradley R.; Riley, Brian J.; Crum, Jarrod V.; Ryan, Joseph V.; Sundaram, S. K.; McCloy, John S.; Rockett, Angus

2009-02-01T23:59:59.000Z

103

Conversion of recoilless gamma-radiation into a periodic sequence of ultrashort pulses in a set of dispersive and absorptive resonant media  

E-Print Network [OSTI]

An efficient technique to produce a periodic sequence of ultrashort pulses of recoilless gamma-radiation via its transmission through the optically thick vibrating resonant absorber was demonstrated recently [Nature, 508, 80 (2014)]. In this work we extend the theoretical analysis to the case of a set of multiple absorbers. We consider an analytical model describing the control of spectral content of a frequency modulated gamma-radiation by selective correction of amplitudes and initial phases of some spectral components, using, respectively, the resonant absorption or dispersion of nuclei. On the basis of the analytical solutions we determine the ultimate possibilities of the proposed technique.

Radeonychev, Y V; Vagizov, F G; Shakhmuratov, R N; Kocharovskaya, Olga

2015-01-01T23:59:59.000Z

104

Conversion of recoilless gamma-radiation into a periodic sequence of ultrashort pulses in a set of dispersive and absorptive resonant media  

E-Print Network [OSTI]

An efficient technique to produce a periodic sequence of ultrashort pulses of recoilless gamma-radiation via its transmission through the optically thick vibrating resonant absorber was demonstrated recently [Nature, 508, 80 (2014)]. In this work we extend the theoretical analysis to the case of a set of multiple absorbers. We consider an analytical model describing the control of spectral content of a frequency modulated gamma-radiation by selective correction of amplitudes and initial phases of some spectral components, using, respectively, the resonant absorption or dispersion of nuclei. On the basis of the analytical solutions we determine the ultimate possibilities of the proposed technique.

Y. V. Radeonychev; V. A. Antonov; F. G. Vagizov; R. N. Shakhmuratov; Olga Kocharovskaya

2015-01-02T23:59:59.000Z

105

Red shift in spectra of galaxies as a consequence of gravitational radiation of the same level as electromagnetic  

E-Print Network [OSTI]

In elaboration of the results presented earlier the red shift is also regarded in this investigation as a widening of electromagnetic radiation spectra, determined by the existence of gravitational radiation of a banded spectrum of the same level as electromagnetic.

S. I. Fisenko; I. S. Fisenko

2010-01-07T23:59:59.000Z

106

OBSERVATIONAL SIGNATURES OF SUB-PHOTOSPHERIC RADIATION-MEDIATED SHOCKS IN THE PROMPT PHASE OF GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

A shock that forms below the photosphere of a gamma-ray burst (GRB) outflow is mediated by Compton scattering of radiation advected into the shock by the upstream fluid. The characteristic scale of such a shock, a few Thomson depths, is larger than any kinetic scale involved by several orders of magnitude. Hence, unlike collisionless shocks, radiation-mediated shocks cannot accelerate particles to nonthermal energies. The spectrum emitted by a shock that emerges from the photosphere of a GRB jet reflects the temperature profile downstream of the shock, with a possible contribution at the highest energies from the shock transition layer itself. We study the properties of radiation-mediated shocks that form during the prompt phase of GRBs and compute the time-integrated spectrum emitted by the shocked fluid following shock breakout. We show that the time-integrated emission from a single shock exhibits a prominent thermal peak, with the location of the peak depending on the shock velocity profile. We also point out that multiple shock emission can produce a spectrum that mimics a Band spectrum.

Levinson, Amir, E-mail: Levinson@wise.tau.ac.il [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309-0440 (United States)

2012-09-10T23:59:59.000Z

107

Handheld CZT radiation detector  

DOE Patents [OSTI]

A handheld CZT radiation detector having a CZT gamma-ray sensor, a multichannel analyzer, a fuzzy-logic component, and a display component is disclosed. The CZT gamma-ray sensor may be a coplanar grid CZT gamma-ray sensor, which provides high-quality gamma-ray analysis at a wide range of operating temperatures. The multichannel analyzer categorizes pulses produce by the CZT gamma-ray sensor into channels (discrete energy levels), resulting in pulse height data. The fuzzy-logic component analyzes the pulse height data and produces a ranked listing of radioisotopes. The fuzzy-logic component is flexible and well-suited to in-field analysis of radioisotopes. The display component may be a personal data assistant, which provides a user-friendly method of interacting with the detector. In addition, the radiation detector may be equipped with a neutron sensor to provide an enhanced mechanism of sensing radioactive materials.

Murray, William S.; Butterfield, Kenneth B.; Baird, William

2004-08-24T23:59:59.000Z

108

Modeling of the $\\gamma$-ray pulsed spectra of Geminga, Crab, and Vela with synchro-curvature radiation  

E-Print Network [OSTI]

$\\gamma$-ray spectra of pulsars have been mostly studied in a phenomenological way, by fitting them to a cut-off power-law function. Here, we analyze a model where pulsed emission comes from synchro-curvature processes in a gap. We calculate the variation of kinetic energy of magnetospheric particles along the gap and the associated radiated spectra, considering an effective particle distribution. We fit the phase-averaged and phase-resolved {\\em Fermi}-LAT spectra of the three brightest $\\gamma$-ray pulsars: Geminga, Crab, and Vela, and constrain the three free parameters we leave free in the model. Our best-fit models well reproduce the observed data, apart from residuals above a few GeV in some cases, range for which the inverse Compton scattering likely becomes the dominant mechanism. In any case, the flat slope at low-energy ($\\lesssim$ GeV) seen by {\\it Fermi}-LAT both in the phase-averaged and phase-resolved spectra of most pulsars, including the ones we studied, requires that most of the detected radi...

Viganò, Daniele

2015-01-01T23:59:59.000Z

109

Combination of /sup 60/Co. gamma. -radiation, misonidazole, and maltose tetrapalmitate in the treatment of Dunning prostatic tumor in the rat  

SciTech Connect (OSTI)

Maltose tetrapalmitate (MTP), a synthetic nontoxic immunoadjuvant, the radiosensitizer misonidazole (MISO), and /sup 60/Co ..gamma..-radiation, alone or in combination, were used in the management of Dunning prostatic tumor in the rat. Nine groups of 10 rats each were used to assess the efficacy of various therapeutic modalities. Tumor growth rates and animal survival times were determined for each group. Radiation was more effective when combined with MTP, but the adjuvant must be present when radiation is given for synergism to occur. MISO was as effective as MTP when used with radiation, but combining them cancels out their individual effects. In a clinical situation it would be advantageous to use separately the synergisms existing between MISO and radiation on the one hand and MTP and radiation on the other hand.

Pageau, R.; Nigam, V.N.; Fisher, G.J.; Brailovsky, C.A.; Fathi, M.A.; Corcos, J.; Tahan, T.W.; Elhilali, M.M.

1985-08-01T23:59:59.000Z

110

CONTRIBUTION OF GAMMA-RAY-LOUD RADIO GALAXIES' CORE EMISSIONS TO THE COSMIC MeV AND GeV GAMMA-RAY BACKGROUND RADIATION  

SciTech Connect (OSTI)

The Fermi gamma-ray satellite has recently detected gamma-ray emissions from radio galaxy cores. From these samples, we first examine the correlation between the luminosities at 5 GHz, L{sub 5GHz}, and at 0.1-10 GeV, L{sub {gamma}}, of gamma-ray-loud radio galaxies. We find that the correlation is significant with L{sub {gamma}}{proportional_to}L{sup 1.16}{sub 5GHz} based on a partial correlation analysis. Using this correlation and the radio luminosity function (RLF) of radio galaxies, we explore the contribution of gamma-ray-loud radio galaxies to the unresolved extragalactic gamma-ray background (EGRB). The gamma-ray luminosity function is obtained by normalizing the RLF to reproduce the source-count distribution of the Fermi gamma-ray-loud radio galaxies. We find that gamma-ray-loud radio galaxies can explain {approx}25% of the unresolved Fermi EGRB flux above 100 MeV and will also make a significant contribution to the EGRB in the 1-30 MeV energy band. Since blazars explain 22% of the EGRB above 100 MeV, radio-loud active galactic nucleus populations explain {approx}47% of the unresolved EGRB. We further make an interpretation on the origin of the EGRB. The observed EGRB spectrum at 0.2-100 GeV does not show an absorption signature by the extragalactic background light. Thus, the dominant population of the origin of EGRB at very high energy (>30 GeV) might be either nearby gamma-ray-emitting sources or sources with very hard gamma-ray spectra.

Inoue, Yoshiyuki, E-mail: yinoue@kusastro.kyoto-u.ac.jp [Department of Astronomy, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

2011-05-20T23:59:59.000Z

111

Radiative heating of the ISCCP upper level cloud regimes and its impact on the large-scale tropical circulation  

E-Print Network [OSTI]

Radiative heating of the ISCCP upper level cloud regimes and its impact on the large-scale tropical 2012; accepted 14 December 2012; published 31 January 2013. [1] Radiative heating profiles. The resulting radiative heating profiles have maxima of approximately 1 K/day near 12 km, with equal heating

112

Luffa fibers and gamma radiation as improvement tools of polymer Gonzalo Martnez-Barrera a,  

E-Print Network [OSTI]

, 4200-465 Porto, Portugal c Institute of Mechanical Engineering and Industrial Management (INEGI. The highest bending deformation is obtained with 0.9 wt% of fibers and 100 kGy of radiation dose. Ã? 2013, silica fume, silica sand; the last one the most used due to size distribution, ranging from 0.6 to 4.0 mm

North Texas, University of

113

LOW TEMPERATURE PHYSICS The effect of neutron and gamma radiation on  

E-Print Network [OSTI]

PHYSICS Outlook · Radiation environment in a fission reactor ­ Neutron and - spectrum · Damage production, iterlaminar shear strength, fatigue behavior ­ Gas evolution · Conclusions #12;LOW TEMPERATURE PHYSICS Fission to displace one atom: (epithermal and fast neutrons) Bp EE > ~4 eV C-H ~few eV in metals ~5-40 eV in ionic

McDonald, Kirk

114

Gamma-ray waveguides  

SciTech Connect (OSTI)

We have developed an approach for gamma-ray optics using layered structures acting as planar waveguides. Experiments demonstrating channeling of 122 keV gamma rays in two prototype waveguides validate the feasibility of this technology. Gamma-ray waveguides allow one to control the direction of radiation up to a few MeV. The waveguides are conceptually similar to polycapillary optics, but can function at higher gamma-ray energies. Optics comprised of these waveguides will be able to collect radiation from small solid angles or concentrate radiation into small area detectors. Gamma-ray waveguides may find applications in medical imaging and treatment, astrophysics, and homeland security.

Tournear, D. M.; Hoffbauer, M. A.; Akhadov, E. A.; Chen, A. T.; Pendleton, S. J.; Williamson, T. L.; Cha, K. C.; Epstein, R. I. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2008-04-14T23:59:59.000Z

115

Experimental and Simulation of Gamma Radiation Dose Rate for High Exposure Building Material  

E-Print Network [OSTI]

Natural radioactivity concentrations in high exposure building materials are commonly used in Iran, which is measured a direct exposure by using {\\gamma}-ray spectrometry. The values for 226Ra, 232Th and 40K were in the ranges 3.8 - 94.2, 6.5 - 172.2 and 556.9 - 1539.2 Bqkg-1, respectively. The absorbed dose rates in the standard dwelling room due to 238U, 232Th series and 40K were calculated with MCNPX code. The simulation and experimental results were between 7.95 - 41.74 and 8.36 - 39.99 nGy h-1, respectively. These results were compared with experimental outing and there was overlap closely. The simulation results are able to develop for any kind of dwelling places.

Abbasi, Akbar

2015-01-01T23:59:59.000Z

116

Experimental and Simulation of Gamma Radiation Dose Rate for High Exposure Building Material  

E-Print Network [OSTI]

Natural radioactivity concentrations in high exposure building materials are commonly used in Iran, which is measured a direct exposure by using {\\gamma}-ray spectrometry. The values for 226Ra, 232Th and 40K were in the ranges 3.8 - 94.2, 6.5 - 172.2 and 556.9 - 1539.2 Bqkg-1, respectively. The absorbed dose rates in the standard dwelling room due to 238U, 232Th series and 40K were calculated with MCNPX code. The simulation and experimental results were between 7.95 - 41.74 and 8.36 - 39.99 nGy h-1, respectively. These results were compared with experimental outing and there was overlap closely. The simulation results are able to develop for any kind of dwelling places.

Akbar Abbasi; Mustfa Hassanzadeh

2014-10-27T23:59:59.000Z

117

Energy levels and radiative transition rates for Ge XXXI, As XXXII, and Se XXXIII  

SciTech Connect (OSTI)

Fine-structure energies of the 67 levels belonging to the 1s{sup 2}, 1s 2l, 1s3l, 1s4l, 1s5l, and 1s6l configurations of Ge XXXI, As XXXII, and Se XXXIII have been calculated using the General-Purpose Relativistic Atomic Structure Package. In addition, radiative rates, oscillator strengths, transition wavelengths, and line strengths have been calculated for all electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions among these levels. Lifetimes are also presented for all excited levels of these three ions. We have compared our results with the results available in the literature and the accuracy of the data is assessed. We predict new energy levels, oscillator strengths, and transition probabilities where no other theoretical or experimental results are available, which will form the basis for future experimental work.

Aggarwal, Sunny, E-mail: sunny.du87@gmail.com; Singh, J.; Jha, A.K.S.; Mohan, Man

2014-07-15T23:59:59.000Z

118

Effect of {gamma}-ray radiation on electrical properties of heat-treated Tb{sub x}Sn{sub 1-x}Se single crystals  

SciTech Connect (OSTI)

The effect of {gamma}-ray radiation on the electrical properties of heat-treated Tb{sub 0.01}Sn{sub 0.99}Se (sample 1) and Tb{sub 0.05}Sn{sub 0.95}Se (sample 2) samples is studied. It is found that, as a result of irradiation with {gamma}-ray 1.25-MeV photons, the charge-carrier concentration decreases in the temperature range T = 77-200 K by 17 and 6.3% for samples 1 and 2, respectively. It is assumed that, in the course of irradiation with {gamma}-ray photons, terbium impurity atoms are located between sites of the crystal lattice; in addition, Frenkel defects are formed.

Huseynov, J. I., E-mail: cih_58@mail.ru; Jafarov, T. A. [Azerbaijan State Pedagogical University (Azerbaijan)

2012-04-15T23:59:59.000Z

119

Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures  

SciTech Connect (OSTI)

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2013-11-01T23:59:59.000Z

120

Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level  

E-Print Network [OSTI]

. Hassanein Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University of protons (about 87 percent) [1]. After impacting the upper atmosphere, high-energy protons interact in the Earth's atmosphere, at sea level, and underground [3]. Many of the studies have been focused on nuclear

Harilal, S. S.

Note: This page contains sample records for the topic "gamma radiation levels" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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121

Hubble diagrams of soft and hard radiation sources in the graviton background: to an apparent contradiction between supernova 1a and gamma-ray burst observations  

E-Print Network [OSTI]

In the sea of super-strong interacting gravitons, non-forehead collisions with gravitons deflect photons, and this deflection may differ for soft and hard radiations. As a result, the Hubble diagram would not be a universal function and it will have a different view for such sources as supernovae in visible light and gamma-ray bursts. Observations of these two kinds are compared here with the limit cases of the Hubble diagram.

Michael A. Ivanov

2007-01-10T23:59:59.000Z

122

Low Dose Radiation Response Curves, Networks and Pathways in Human Lymphoblastoid Cells Exposed from 1 to 10 cGy of Acute Gamma Radiation  

E-Print Network [OSTI]

R.B. Mikkelsen, Ionizing radiation-induced, mitochondria-W.K. Rorrer, P.B. Chen, Radiation-induced proliferation ofresponse genes to ionizing radiation in human lymphoblastoid

Wyrobek, A. J.

2011-01-01T23:59:59.000Z

123

Directional gamma detector  

DOE Patents [OSTI]

An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

LeVert, Francis E. (Downers Grove, Knoxville, TN); Cox, Samson A. (Downers Grove, IL)

1981-01-01T23:59:59.000Z

124

Higgs boson decay to mu mubar gamma  

E-Print Network [OSTI]

The Higgs boson decay, H -> mu mubar gamma, is studied in the Standard Model at the tree and one-loop levels. It is shown that for Higgs boson masses above 110 GeV, the contribution to the radiative width from the one-loop level exceeds the contribution from the tree level, and for Higgs boson masses above 140 GeV, it even exceeds the contribution from the tree level decay H -> mu mubar. We also show that the contributions to the radiative decay width from the interference terms between the tree and one-loop diagrams are negligible.

Ali Abbasabadi; Wayne W. Repko

2000-04-17T23:59:59.000Z

125

Report to the DOE nuclear data committee. [EV RANGE 10-100; CROSS SECTIONS; PHOTONEUTRONS; NEUTRONS; GAMMA RADIATION; COUPLED CHANNEL THEORY; DIFFERENTIAL CROSS SECTIONS; MEV RANGE 01-10; ; CAPTURE; GAMMA SPECTRA; THERMAL NEUTRONS; COMPUTER CALCULATIONS; DECAY; FISSION PRODUCTS; FISSION YIELD; SHELL MODELS; NUCLEAR DATA COLLECTIONS  

SciTech Connect (OSTI)

Topics covered include: studies of (n, charged particle) reactions with 14 to 15 MeV neutrons; photoneutron cross sections for /sup 15/N; neutron radiative capture; Lane-model analysis of (p,p) and (n,n) scattering on the even tin isotopes; neutron scattering cross sections for /sup 181/Ta, /sup 197/Au, /sup 209/Bi, /sup 232/Th, and /sup 238/U inferred from proton scattering and charge exchange cross sections; neutron-induced fission cross sections of /sup 245/Cm and /sup 242/Am; fission neutron multiplicities for /sup 245/Cm and /sup 242/Am; the transport of 14 MeV neutrons through heavy materials 150 < A < 208; /sup 249/Cm energy levels from measurement of thermal neutron capture gamma rays; /sup 231/Th energy levels from neutron capture gamma ray and conversion electron spectroscopy; new measurements of conversion electron binding energies in berkelium and californium; nuclear level densities; relative importance of statistical vs. valence neutron capture in the mass-90 region; determination of properties of short-lived fission products; fission yield of /sup 87/Br and /sup 137/I from 15 nuclei ranging from /sup 232/Th to /sup 249/Cf; evaluation of charged particle data for the ECPL library; evaluation of secondary charged-particle energy and angular distributions for ENDL; and evaluated nuclear structure libraries derived from the table of isotopes. (GHT)

Struble, G.L.; Haight, R.C.

1981-03-01T23:59:59.000Z

126

Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels  

SciTech Connect (OSTI)

A fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-05 straight section is currently used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With the maximum magnetic field of 72.5 Gauss, it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-06 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using three horizontal kickers in the Long-12 section. STRUCT calculations show that using horizontal notchers, one can remove up to 96% of the 3-bunch intensity at 400-700 MeV, directing 95% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.

Rakhno, I.L.; Drozhdin, A.I.; Mokhov, N.V.; Sidorov, V.I.; Tropin, I.S.; /Fermilab

2012-05-14T23:59:59.000Z

127

Energy levels, radiative rates and electron impact excitation rates for transitions in C III  

E-Print Network [OSTI]

We report energy levels, radiative rates (A-values) and lifetimes for the astrophysically-important Be-like ion C III. For the calculations, 166 levels belonging to the $n \\le$ 5 configurations are considered and the {\\sc grasp} (General-purpose Relativistic Atomic Structure Package) is adopted. Einstein A-coefficients are provided for all E1, E2, M1 and M2 transitions, while lifetimes are compared with available measurements as well as theoretical results, and no large discrepancies noted. Our energy levels are assessed to be accurate to better than 1\\% for a majority of levels, and A-values to better than 20\\% for most transitions. Collision strengths are also calculated, for which the Dirac Atomic R-matrix Code ({\\sc darc}) is used. A wide energy range, up to 21 Ryd, is considered and resonances resolved in a fine energy mesh in the thresholds region. The collision strengths are subsequently averaged over a Maxwellian velocity distribution to determine effective collision strengths up to a temperature of 8...

Aggarwal, K M

2015-01-01T23:59:59.000Z

128

Testing and Performance Validation of a Sensitive Gamma Ray Camera Designed for Radiation Detection and Decommissioning Measurements in Nuclear Facilities-13044  

SciTech Connect (OSTI)

This paper describes the measurements, testing and performance validation of a sensitive gamma ray camera designed for radiation detection and quantification in the environment and decommissioning and hold-up measurements in nuclear facilities. The instrument, which is known as RadSearch, combines a sensitive and highly collimated LaBr{sub 3} scintillation detector with an optical (video) camera with controllable zoom and focus and a laser range finder in one detector head. The LaBr{sub 3} detector has a typical energy resolution of between 2.5% and 3% at the 662 keV energy of Cs-137 compared to that of NaI detectors with a resolution of typically 7% to 8% at the same energy. At this energy the tungsten shielding of the detector provides a shielding ratio of greater than 900:1 in the forward direction and 100:1 on the sides and from the rear. The detector head is mounted on a pan/tile mechanism with a range of motion of ±180 degrees (pan) and ±90 degrees (tilt) equivalent to 4 ? steradians. The detector head with pan/tilt is normally mounted on a tripod or wheeled cart. It can also be mounted on vehicles or a mobile robot for access to high dose-rate areas and areas with high levels of contamination. Ethernet connects RadSearch to a ruggedized notebook computer from which it is operated and controlled. Power can be supplied either as 24-volts DC from a battery or as 50 volts DC supplied by a small mains (110 or 230 VAC) power supply unit that is co-located with the controlling notebook computer. In this latter case both power and Ethernet are supplied through a single cable that can be up to 80 metres in length. If a local battery supplies power, the unit can be controlled through wireless Ethernet. Both manual operation and automatic scanning of surfaces and objects is available through the software interface on the notebook computer. For each scan element making up a part of an overall scanned area, the unit measures a gamma ray spectrum. Multiple radionuclides may be selected by the operator and will be identified if present. In scanning operation the unit scans a designated region and superimposes over a video image the distribution of measured radioactivity. For the total scanned area or object RadSearch determines the total activity of operator selected radionuclides present and the gamma dose-rate measured at the detector head. Results of hold-up measurements made in a nuclear facility are presented, as are test measurements of point sources distributed arbitrarily on surfaces. These latter results are compared with the results of benchmarked MCNP Monte Carlo calculations. The use of the device for hold-up and decommissioning measurements is validated. (authors)

Mason, John A.; Looman, Marc R.; Poundall, Adam J.; Towner, Antony C.N. [ANTECH, A. N. Technology Ltd., Unit 6, Thames Park, Wallingford, Oxfordshire, OX10 9TA (United Kingdom)] [ANTECH, A. N. Technology Ltd., Unit 6, Thames Park, Wallingford, Oxfordshire, OX10 9TA (United Kingdom); Creed, Richard; Pancake, Daniel [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)] [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)

2013-07-01T23:59:59.000Z

129

Radiative Heating of the ISCCP Upper Level Cloud Regimes and its Impact on the Large-scale Tropical Circulation  

SciTech Connect (OSTI)

Radiative heating profiles of the International Satellite Cloud Climatology Project (ISCCP) cloud regimes (or weather states) were estimated by matching ISCCP observations with radiative properties derived from cloud radar and lidar measurements from the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) sites at Manus, Papua New Guinea, and Darwin, Australia. Focus was placed on the ISCCP cloud regimes containing the majority of upper level clouds in the tropics, i.e., mesoscale convective systems (MCSs), deep cumulonimbus with cirrus, mixed shallow and deep convection, and thin cirrus. At upper levels, these regimes have average maximum cloud occurrences ranging from 30% to 55% near 12 km with variations depending on the location and cloud regime. The resulting radiative heating profiles have maxima of approximately 1 K/day near 12 km, with equal heating contributions from the longwave and shortwave components. Upper level minima occur near 15 km, with the MCS regime showing the strongest cooling of 0.2 K/day and the thin cirrus showing no cooling. The gradient of upper level heating ranges from 0.2 to 0.4 K/(day?km), with the most convectively active regimes (i.e., MCSs and deep cumulonimbus with cirrus) having the largest gradient. When the above heating profiles were applied to the 25-year ISCCP data set, the tropics-wide average profile has a radiative heating maximum of 0.45Kday-1 near 250 hPa. Column-integrated radiative heating of upper level cloud accounts for about 20% of the latent heating estimated by the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). The ISCCP radiative heating of tropical upper level cloud only slightly modifies the response of an idealized primitive equation model forced with the tropics-wide TRMM PR latent heating, which suggests that the impact of upper level cloud is more important to large-scale tropical circulation variations because of convective feedbacks rather than direct forcing by the cloud radiative heating profiles. However, the height of the radiative heating maxima and gradient of the heating profiles are important to determine the sign and patterns of the horizontal circulation anomaly driven by radiative heating at upper levels.

Li, Wei; Schumacher, Courtney; McFarlane, Sally A.

2013-01-31T23:59:59.000Z

130

Essay on the gamma ray laser  

E-Print Network [OSTI]

This work discusses the possibility of inducing the emission of gamma radiation from nuclear isomers by two-photon transitions, in the more general context of the problem of the amplification of gamma radiation.

Silviu Olariu

1999-07-18T23:59:59.000Z

131

Miniaturized radiation chirper  

DOE Patents [OSTI]

The disclosure relates to a miniaturized radiation chirper for use with a small battery supplying on the order of 5 volts. A poor quality CdTe crystal which is not necessarily suitable for high resolution gamma ray spectroscopy is incorporated with appropriate electronics so that the chirper emits an audible noise at a rate that is proportional to radiation exposure level. The chirper is intended to serve as a personnel radiation warning device that utilizes new and novel electronics with a novel detector, a CdTe crystal. The resultant device is much smaller and has much longer battery life than existing chirpers.

Umbarger, C. John (Los Alamos, NM); Wolf, Michael A. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

132

Tests of the radiation hardness of VLSI Integrated Circuits and Silicon Strip Detectors for the SSC (Superconducting Super Collider) under neutron, proton, and gamma irradiation  

SciTech Connect (OSTI)

As part of a program to develop a silicon strip central tracking detector system for the Superconducting Super Collider (SSC) we are studying the effects of radiation damage in silicon detectors and their associated front-end readout electronics. We report on the results of neutron and proton irradiations at the Los Alamos National Laboratory (LANL) and {gamma}-ray irradiations at UC Santa Cruz (UCSC). Individual components on single-sided AC-coupled silicon strip detectors and on test structures were tested. Circuits fabricated in a radiation hard CMOS process and individual transistors fabricated using dielectric isolation bipolar technology were also studied. Results indicate that a silicon strip tracking detector system should have a lifetime of at least one decade at the SSC. 17 refs., 17 figs.

Ziock, H.J.; Milner, C.; Sommer, W.F. (Los Alamos National Lab., NM (USA)); Carteglia, N.; DeWitt, J.; Dorfan, D.; Hubbard, B.; Leslie, J.; O'Shaughnessy, K.F.; Pitzl, D.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E. (California Univ., Santa Cruz, CA (USA). Inst. for Particle Physics); Ellison, J.A. (California Univ., Riverside, CA (USA)); Ferguson, P. (Missouri Univ., Rolla, MO (USA)); Giubellino

1990-01-01T23:59:59.000Z

133

Measurement of the W Gamma --> mu nu gamma Cross-Section, Limits on Anomalous Trilinear Vector Boson Couplings, and the Radiation Amplitude Zero in p anti-p Collisions at s**(1/2) = 1.96 TeV  

SciTech Connect (OSTI)

This thesis details the measurement of the p{bar p} {yields} W{gamma} + X {yields} {mu}{nu}{gamma} + X cross section at {radical}s = 1.96 TeV using the D0 detector at Fermilab, in 134.5 pb{sup -1} of integrated luminosity. From the photon E{sub T} spectrum limits on anomalous couplings of the photon to the W are obtained. At 95% confidence level, limits of -1.05 < {Delta}{kappa} < 1.04 for {lambda} = 0 and -0.28 < {lambda} < 0.27 for {Delta}{kappa} = 0 are obtained on the anomalous coupling parameters. The charge signed rapidity difference from the data is displayed, and its significance discussed.

Askew, Andrew Warren

2004-11-01T23:59:59.000Z

134

Gamma decay of unbound states following neutron capture  

SciTech Connect (OSTI)

Neutron capture ..gamma..-ray spectroscopy is a powerful technique to study the ..gamma..-decay of unbound levels just above the neutron separation energy. It is generally believed that the (n,..gamma..) reaction proceeds by way of a compound nucleus reaction of great complexity; and, therefore, the capture ..gamma..-ray spectrum should be describable in terms of statistical laws. However, measurements have shown that effects are present due to single-particle motions and due to giant resonances. The study of (n,..gamma..) spectra averaged over as many resonances as possible provides one of the best experimental means of directly obtaining reliable values for radiative transition probabilities from highly excited nuclear states. In very select cases, unbound levels which are populated in allowed ..beta.. decay can also be observed as neutron resonances. These ideas are illustrated with examples of recent data.

Raman, S.

1982-01-01T23:59:59.000Z

135

RADIATION MECHANISM AND JET COMPOSITION OF GAMMA-RAY BURSTS AND GeV-TeV-SELECTED RADIO-LOUD ACTIVE GALACTIC NUCLEI  

SciTech Connect (OSTI)

Gamma-ray bursts (GRBs) and GeV-TeV-selected radio-loud active galactic nuclei (AGNs) are compared based on our systematic modeling of the observed spectral energy distributions of a sample of AGNs with a single-zone leptonic model. We show that the correlation between the jet power (P{sub jet}) and the prompt gamma-ray luminosity (L{sub jet}) of GRBs is consistent, within the uncertainties, with the correlation between jet power and the synchrotron peak luminosity (L{sub s,jet}) of flat spectrum radio quasars (FSRQs). Their radiation efficiencies ({epsilon}) are also comparable (>10% for most sources), which increase with the bolometric jet luminosity (L{sub bol,jet}) for FSRQs and with the L{sub jet} for GRBs with similar power-law indices. BL Lac objects (BL Lacs) do not follow the P{sub jet}-L{sub s,jet} relation of FSRQs. They have lower {epsilon} and L{sub bol,jet} values than FSRQs, and a tentative L{sub bol,jet}-{epsilon} relation is also found, with a power-law index different from that of the FSRQs. The magnetization parameters ({sigma}) of FSRQs are on average larger than that of BL Lacs. They are anti-correlated with {epsilon} for the FSRQs, but positively correlated with {epsilon} for the BL Lacs. GeV narrow-line Seyfert 1 galaxies potentially share similar properties with FSRQs. Based on the analogy between GRBs and FSRQs, we suggest that the prompt gamma-ray emission of GRBs is likely produced by the synchrotron process in a magnetized jet with high radiation efficiency, similar to FSRQs. The jets of BL Lacs, on the other hand, are less efficient and are likely more matter-dominated.

Zhang Jin; Lu Ye; Zhang Shuangnan [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Liang Enwei; Sun Xiaona [Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Zhang Bing, E-mail: lew@gxu.edu.cn [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

2013-09-01T23:59:59.000Z

136

Design and Operation of a tunable MeV-level Compton-scattering-based (gamma-ray) source  

SciTech Connect (OSTI)

A mono-energetic gamma-ray (MEGa-ray) source based on Compton-scattering, targeting nuclear physics applications such as nuclear resonance fluorescence, has been constructed and commissioned at Lawrence Livermore National Laboratory. In this paper, the overall architecture of the system, as well as some of the critical design decisions made in the development of the source, are discussed. The performances of the two laser systems (one for electron production, one for scattering), the electron photoinjector, and the linear accelerator are also detailed, and initial {gamma}-ray results are presented.

Gibson, D J; Albert, F; Anderson, S G; Betts, S M; Messerly, M J; Phan, H H; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P; Barty, C P

2009-07-07T23:59:59.000Z

137

Blazar Duty-Cycle at gamma-ray Frequecies: Constraints from Extragalactic Background Radiation and Prospects for AGILE and GLAST  

E-Print Network [OSTI]

We take into account the constraints from the observed extragalactic gamma-ray background to estimate the maximum duty cycle allowed for a selected sample of WMAP Blazars, in order to be detectable by AGILE and GLAST gamma-ray experiments. For the nominal sensitivity values of both instruments, we identify a subset of sources which can in principle be detectable also in a steady state without over-predicting the extragalactic background. This work is based on the results of a recently derived Blazar radio LogN-LogS obtained by combining several multi-frequency surveys.

Pittori, Carlotta; Colafrancesco, Sergio; Giommi, Paolo

2007-01-01T23:59:59.000Z

138

Blazar Duty-Cycle at gamma-ray Frequecies: Constraints from Extragalactic Background Radiation and Prospects for AGILE and GLAST  

E-Print Network [OSTI]

We take into account the constraints from the observed extragalactic gamma-ray background to estimate the maximum duty cycle allowed for a selected sample of WMAP Blazars, in order to be detectable by AGILE and GLAST gamma-ray experiments. For the nominal sensitivity values of both instruments, we identify a subset of sources which can in principle be detectable also in a steady state without over-predicting the extragalactic background. This work is based on the results of a recently derived Blazar radio LogN-LogS obtained by combining several multi-frequency surveys.

Carlotta Pittori; Elisabetta Cavazzuti; Sergio Colafrancesco; Paolo Giommi

2007-05-04T23:59:59.000Z

139

Gamma-Gamma Colliders  

E-Print Network [OSTI]

a gamma collider, we need to discuss the laser optics in thegamma collider will be given later, coupled with some discussions of the requisite opticsoptics and an adequate laser for Compton conversion. With this approach, the luminosity for the gamma-

Kim, K.-J.

2008-01-01T23:59:59.000Z

140

Semiquantitative Analysis Using Thallium-201 SPECT for Differential Diagnosis Between Tumor Recurrence and Radiation Necrosis After Gamma Knife Surgery for Malignant Brain Tumors  

SciTech Connect (OSTI)

Purpose: Semiquantitative analysis of thallium-201 chloride single photon emission computed tomography ({sup 201}Tl SPECT) was evaluated for the discrimination between recurrent brain tumor and delayed radiation necrosis after gamma knife surgery (GKS) for metastatic brain tumors and high-grade gliomas. Methods and Materials: The medical records were reviewed of 75 patients, including 48 patients with metastatic brain tumor and 27 patients with high-grade glioma who underwent GKS in our institution, and had suspected tumor recurrence or radiation necrosis on follow-up neuroimaging and deteriorating clinical status after GKS. Analysis of {sup 201}Tl SPECT data used the early ratio (ER) and the delayed ratio (DR) calculated as tumor/normal average counts on the early and delayed images, and the retention index (RI) as the ratio of DR to ER. Results: A total of 107 tumors were analyzed with {sup 201}Tl SPECT. Nineteen lesions were removed surgically and histological diagnoses established, and the other lesions were evaluated with follow-up clinical and neuroimaging examinations after GKS. The final diagnosis was considered to be recurrent tumor in 65 lesions and radiation necrosis in 42 lesions. Semiquantitative analysis demonstrated significant differences in DR (P=.002) and RI (P<.0001), but not in ER (P=.372), between the tumor recurrence and radiation necrosis groups, and no significant differences between metastatic brain tumors and high-grade gliomas in all indices (P=.926 for ER, P=.263 for DR, and P=.826 for RI). Receiver operating characteristics analysis indicated that RI was the most informative index with the optimum threshold of 0.775, which provided 82.8% sensitivity, 83.7% specificity, and 82.8% accuracy. Conclusions: Semiquantitative analysis of {sup 201}Tl SPECT provides useful information for the differentiation between tumor recurrence and radiation necrosis in metastatic brain tumors and high-grade gliomas after GKS, and the RI may be the most valuable index for this purpose.

Matsunaga, Shigeo, E-mail: shigeo-m@mui.biglobe.ne.jp [Department of Neurosurgery, Yokohama Rosai Hospital, Yokohama, Kanagawa (Japan)] [Department of Neurosurgery, Yokohama Rosai Hospital, Yokohama, Kanagawa (Japan); Shuto, Takashi; Takase, Hajime; Ohtake, Makoto; Tomura, Nagatsuki; Tanaka, Takahiro; Sonoda, Masaki [Department of Neurosurgery, Yokohama Rosai Hospital, Yokohama, Kanagawa (Japan)] [Department of Neurosurgery, Yokohama Rosai Hospital, Yokohama, Kanagawa (Japan)

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Report on policy and activities concerning public awareness of health effects of low-level radiation  

SciTech Connect (OSTI)

In the summer of 1986, the Executive Committee authorized a study limited to determining policy and practices relevant to dissemination of information to the public on radiation health effects in three federal agencies. This report summarizes findings on two broad questions related to the communication issue: What, if any, are the policies under which federal agencies operate in disseminating information on health effects of radiation and what are the current programs and activities designed to provide the public information on health effects of radiation.

NONE

1986-11-01T23:59:59.000Z

142

High-energy radiation visualizer (HERV): A new system for imaging in x-ray and gamma-ray emission regions  

SciTech Connect (OSTI)

The authors present a description and results of the operation for {gamma}-ray and X-ray objects for the compact visualization system high-energy radiation visualizer (HERV). The imaging in this system is based on use of a conical collimator, scintillator plate, and image intensifier as a detector and CCD matrix as a readout device. The use of HERV as a two-dimensional X-ray image visualizer for the Compton scatter inspection system was considered and first results are discussed. The possibility of using different hexagonal-coded apertures imaging for HERV is discussed and results of Monte Carlo simulation and experiments with optical analog of coded aperture are presented.

Sudarkin, A.N.; Ivanov, O.P.; Stepanov, V.E.; Volkovich, A.G.; Turin, A.S.; Danilovich, A.S.; Rybakov, D.D.; Urutskoev, L.I. [RECOM Ltd., Moscow (Russian Federation)] [RECOM Ltd., Moscow (Russian Federation)

1996-08-01T23:59:59.000Z

143

Energy levels, radiative rates, and electron impact excitation rates for transitions in Li-like ions with 21?Z?28  

SciTech Connect (OSTI)

We report calculations of energy levels, radiative rates, and electron impact excitation rates for transitions in Li-like ions with 21?Z?28. The General-Purpose Relativistic Atomic Structure Package is adopted for calculating energy levels and radiative rates, while for determining the collision strengths and subsequently the excitation rates, the Dirac Atomic R-matrix Code is used. Oscillator strengths, radiative rates, and line strengths are listed for all E1, E2, M1, and M2 transitions among the lowest 24 levels of the Li-like ions considered. Collision strengths have been averaged over a Maxwellian velocity distribution, and the effective collision strengths obtained are given over a wide temperature range up to 10{sup 7.8} K. Additionally, lifetimes are listed for all calculated levels of these ions. Finally, extensive comparisons are made with results available in the literature, as well as with our analogous calculations for all parameters with the Flexible Atomic Code, in order to assess the accuracy of the results.

Aggarwal, Kanti M., E-mail: K.Aggarwal@qub.ac.uk; Keenan, Francis P.

2012-11-15T23:59:59.000Z

144

Energy levels, radiative rates, and electron impact excitation rates for transitions in Li-like ions with 12?Z?20  

SciTech Connect (OSTI)

We report calculations of energy levels, radiative rates, and electron impact excitation rates for transitions in Li-like ions with 12?Z?20. The GRASP (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates, while for determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code is used. Oscillator strengths, radiative rates, and line strengths are reported for all E1, E2, M1, and M2 transitions among the lowest 24 levels of the Li-like ions considered. Collision strengths have been averaged over a Maxwellian velocity distribution, and the effective collision strengths obtained are reported over a wide temperature range up to 10{sup 7.4} K. Additionally, lifetimes are also listed for all calculated levels of the ions. Finally, extensive comparisons are made with results available in the literature, as well as with our parallel calculations for all parameters with the Flexible Atomic Code, in order to assess the accuracy of the reported results.

Aggarwal, Kanti M., E-mail: K.Aggarwal@qub.ac.uk; Keenan, Francis P.

2013-03-15T23:59:59.000Z

145

Low Dose Radiation Response Curves, Networks and Pathways in Human Lymphoblastoid Cells Exposed from 1 to 10 cGy of Acute Gamma Radiation  

SciTech Connect (OSTI)

We investigated the low dose dependency of the transcriptional response of human cells to characterize the shape and biological functions associated with the dose response curve and to identify common and conserved functions of low dose expressed genes across cells and tissues. Human lymphoblastoid (HL) cells from two unrelated individuals were exposed to graded doses of radiation spanning the range of 1-10 cGy were analyzed by transcriptome profiling, qPCR and bioinformatics, in comparison to sham irradiated samples. A set of {approx}80 genes showed consistent responses in both cell lines; these genes were associated with homeostasis mechanisms (e.g., membrane signaling, molecule transport), subcellular locations (e.g., Golgi, and endoplasmic reticulum), and involved diverse signal transduction pathways. The majority of radiation-modulated genes had plateau-like responses across 1-10 cGy, some with suggestive evidence that transcription was modulated at doses below 1 cGy. MYC, FOS and TP53 were the major network nodes of the low-dose response in HL cells. Comparison our low dose expression findings in HL cells with those of prior studies in mouse brain after whole body exposure, in human keratinocyte cultures, and in endothelial cells cultures, indicates that certain components of the low dose radiation response are broadly conserved across cell types and tissues, independent of proliferation status.

Wyrobek, A. J.; Manohar, C. F.; Nelson, D. O.; Furtado, M. R.; Bhattacharya, M. S.; Marchetti, F.; Coleman, M.A.

2011-04-18T23:59:59.000Z

146

Radiation dose assessments to support evaluations of radiological control levels for recycling or reuse of materials and equipment  

SciTech Connect (OSTI)

Pacific Northwest Laboratory is providing Environmental Protection Support and Assistance to the USDOE, Office of Environmental Guidance. Air, Water, and Radiation Division. As part of this effort, PNL is collecting data and conducting technical evaluations to support DOE analyses of the feasibility of developing radiological control levels for recycling or reuse of metals, concrete, or equipment containing residual radioactive contamination from DOE operations. The radiological control levels will be risk-based, as developed through a radiation exposure scenario and pathway analysis. The analysis will include evaluation of relevant radionuclides, potential mechanisms of exposure, and both health and non-health-related impacts. The main objective of this report is to develop a methodology for establishing radiological control levels for recycle or reuse. This report provides the results of the radiation exposure scenario and pathway analyses for 42 key radionuclides generated during DOE operations that may be contained in metals or equipment considered for either recycling or reuse. The scenarios and information developed by the IAEA. Application of Exemption Principles to the Recycle and Reuse of Materials from Nuclear Facilities, are used as the initial basis for this study. The analyses were performed for both selected worker populations at metal smelters and for the public downwind of a smelter facility. Doses to the public downwind were estimated using the US (EPA) CAP88-PC computer code with generic data on atmospheric dispersion and population density. Potential non-health-related effects of residual activity on electronics and on film were also analyzed.

Hill, R.L.; Aaberg, R.L.; Baker, D.A.; Kennedy, W.E. Jr.

1995-07-01T23:59:59.000Z

147

System level latchup mitigation for single event and transient radiation effects on electronics  

DOE Patents [OSTI]

A ``blink`` technique, analogous to a person blinking at a flash of bright light, is provided for mitigating the effects of single event current latchup and prompt pulse destructive radiation on a micro-electronic circuit. The system includes event detection circuitry, power dump logic circuitry, and energy limiting measures with autonomous recovery. The event detection circuitry includes ionizing radiation pulse detection means for detecting a pulse of ionizing radiation and for providing at an output terminal thereof a detection signal indicative of the detection of a pulse of ionizing radiation. The current sensing circuitry is coupled to the power bus for determining an occurrence of excess current through the power bus caused by ionizing radiation or by ion-induced destructive latchup of a semiconductor device. The power dump circuitry includes power dump logic circuitry having a first input terminal connected to the output terminal of the ionizing radiation pulse detection circuitry and having a second input terminal connected to the output terminal of the current sensing circuitry. The power dump logic circuitry provides an output signal to the input terminal of the circuitry for opening the power bus and the circuitry for shorting the power bus to a ground potential to remove power from the power bus. The energy limiting circuitry with autonomous recovery includes circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential. The circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential includes a series FET and a shunt FET. The invention provides for self-contained sensing for latchup, first removal of power to protect latched components, and autonomous recovery to enable transparent operation of other system elements. 18 figs.

Kimbrough, J.R.; Colella, N.J.

1997-09-30T23:59:59.000Z

148

System level latchup mitigation for single event and transient radiation effects on electronics  

DOE Patents [OSTI]

A "blink" technique, analogous to a person blinking at a flash of bright light, is provided for mitigating the effects of single event current latchup and prompt pulse destructive radiation on a micro-electronic circuit. The system includes event detection circuitry, power dump logic circuitry, and energy limiting measures with autonomous recovery. The event detection circuitry includes ionizing radiation pulse detection means for detecting a pulse of ionizing radiation and for providing at an output terminal thereof a detection signal indicative of the detection of a pulse of ionizing radiation. The current sensing circuitry is coupled to the power bus for determining an occurrence of excess current through the power bus caused by ionizing radiation or by ion-induced destructive latchup of a semiconductor device. The power dump circuitry includes power dump logic circuitry having a first input terminal connected to the output terminal of the ionizing radiation pulse detection circuitry and having a second input terminal connected to the output terminal of the current sensing circuitry. The power dump logic circuitry provides an output signal to the input terminal of the circuitry for opening the power bus and the circuitry for shorting the power bus to a ground potential to remove power from the power bus. The energy limiting circuitry with autonomous recovery includes circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential. The circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential includes a series FET and a shunt FET. The invention provides for self-contained sensing for latchup, first removal of power to protect latched components, and autonomous recovery to enable transparent operation of other system elements.

Kimbrough, Joseph Robert (Pleasanton, CA); Colella, Nicholas John (Livermore, CA)

1997-01-01T23:59:59.000Z

149

Effects of an acute dose of gamma radiation exposure on stem diameter growth, carbon gain, and biomass partitioning in Helianthus annuus  

SciTech Connect (OSTI)

Nineteen-day-old dwarf sunflower plants (Helianthus annuus, variety NK894) received a variable dose (0-40 Gy) from a cobalt-60 gamma source. A very sensitive stem monitoring device, developed at Battelle's Pacific Northwest Laboratories, Richland, Washington was used to measure real-time changes in stem diameter. Exposure of plants caused a significant reduction in stem growth and root biomass. Doses as low as 5 Gy resulted in a significant increase in leaf density, suggesting that nonreversible morphological growth changes could be induced by very low doses of radiation. Carbohydrate analysis of 40-Gy irradiated plants demonstrated significantly more starch content in leaves and significantly less starch content in stems 18 days after exposure than did control plants. In contrast, the carbohydrate content in roots of 40-Gy irradiated plants were not significantly different from unirradiated plants 18 days after exposure. These results indicate that radiation either decreased phloem transport or reduced the availability of sugar reducing enzymes in irradiated plants. 44 refs., 12 figs.

Thiede, M.E.

1988-05-25T23:59:59.000Z

150

Gamma ray bursts ROBERT S MACKAY  

E-Print Network [OSTI]

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

Rourke, Colin

151

ESTIMATING GROUND-LEVEL SOLAR RADIATION AND EVAPOTRANSPIRATION IN PUERTO RICO  

E-Print Network [OSTI]

REMOTE SENSING Eric. W. Harmsen1 , John Mecikalski2 , Vanessa Acaron3 and Jayson Maldonado3 1 Department insolation, other meteorological variables (e.g., net radiation, soil heat flux, air temperature dew point remote sensing product. As a practical example of the use of the methodology, the Hargraeves-Samani ETo

Gilbes, Fernando

152

Simultaneous beta and gamma spectroscopy  

DOE Patents [OSTI]

A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

Farsoni, Abdollah T. (Corvallis, OR); Hamby, David M. (Corvallis, OR)

2010-03-23T23:59:59.000Z

153

Astrophysical S factor for the radiative-capture reaction p{sup 6}Li {yields} {sup 7}Be{gamma}  

SciTech Connect (OSTI)

A new measurement of differential cross sections for elastic p{sup 6}Li scattering in the energy range 0.35-1.2 MeV was performed. A partial-wave analysis of the data obtained in this way was carried out, and potentials simulating the p{sup 6}Li interaction were constructed. Various experiments devoted to studying elastic p{sup 6}Li scattering over the broad energy range of 0.5-50 MeV were analyzed on the basis of the optical model. By using the potentials obtained from the partial-wave analysis, the possibility of describing the astrophysical S factor for radiative proton capture on {sup 6}Li at low energies was considered within the potential cluster model involving forbidden states.

Dubovichenko, S. B., E-mail: sergey@dubovichenko.ru [National Space Agency of the Republic of Kazakhstan, Fessenkov Astrophysical Institute, National Center of Space Research and Technology (Kazakhstan); Burtebaev, N., E-mail: burteb@inp.kz; Zazulin, D. M.; Kerimkulov, Zh. K. [National Nuclear Center of Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Amar, A. S. A. [Al-Farabi Kazakh National University (Kazakhstan)

2011-07-15T23:59:59.000Z

154

Gamma ray burst outflows and afterglows.  

E-Print Network [OSTI]

?? We carry out a theoretical investigation of jet propagation in Gamma Ray Bursts and examine the jitter radiation mechanism as a means of producing… (more)

Morsony, Brian J.

2009-01-01T23:59:59.000Z

155

Health physics manual of good practices for reducing radiation exposure to levels that are as low as reasonably achievable (ALARA)  

SciTech Connect (OSTI)

A primary objective of the US Department of Energy (DOE) health physics and radiation protection program has been to limit radiation exposures to those levels that are as low as reasonably achievable (ALARA). As a result, the ALARA concept developed into a program and a set of operational principles to ensure that the objective was consistently met. Implementation of these principles required that a guide be produced. The original ALARA guide was issued by DOE in 1980 to promote improved understanding of ALARA concepts within the DOE community and to assist those responsible for operational ALARA activities in attaining their goals. Since 1980, additional guidance has been published by national and international organizations to provide further definition and clarification to ALARA concepts. As basic ALARA experience increased, the value and role of the original guide prompted the DOE Office of Nuclear Safety (ONS) to support a current revision. The revised manual of good practices includes six sections: 1.0 Introduction, 2.0 Administration, 3.0 Optimization, 4.0 Setting and Evaluating ALARA Goals, 5.0 Radiological Design, and 6.0 Conduct of Operations. The manual is directed primarily to contractor and DOE staff who are responsible for conduct and overview of radiation protection and ALARA programs at DOE facilities. The intent is to provide sufficient guidance such that the manual, if followed, will ensure that radiation exposures are maintained as low as reasonably achievable and will establish the basis for a formally structured and auditable program. 118 refs., 16 figs., 3 tabs.

Herrington, W.N.; Higby, D.P.; Kathren,., R.L.; Merwin, S.E.; Stoetzel, G.A.

1988-06-01T23:59:59.000Z

156

The Association between Cancers and Low Level Radiation: an evaluation of the epidemiological evidence at the Hanford Nuclear Weapons Facility  

E-Print Network [OSTI]

indiv. indiv. Gilbertetal. (Hanford & Combined) Gilbertetal.on both radiation and the Hanford facility. The data used toG. Radiation exposures of Hanford workers dying from cancer

Britton, Julie

2010-01-01T23:59:59.000Z

157

Nuclear radiation-warning detector that measures impedance  

DOE Patents [OSTI]

This invention is a nuclear radiation-warning detector that measures impedance of silver-silver halide on an interdigitated electrode to detect light or radiation comprised of alpha particles, beta particles, gamma rays, X rays, and/or neutrons. The detector is comprised of an interdigitated electrode covered by a layer of silver halide. After exposure to alpha particles, beta particles, X rays, gamma rays, neutron radiation, or light, the silver halide is reduced to silver in the presence of a reducing solution. The change from the high electrical resistance (impedance) of silver halide to the low resistance of silver provides the radiation warning that detected radiation levels exceed a predetermined radiation dose threshold.

Savignac, Noel Felix; Gomez, Leo S; Yelton, William Graham; Robinson, Alex; Limmer, Steven

2013-06-04T23:59:59.000Z

158

Fully automated radiochemical preparation system for gamma-spectroscopy on fission products and the study of the intruder and vibrational levels in /sup 83/Se  

SciTech Connect (OSTI)

AUTOBATCH was developed to provide a usable source of short-lived neutron-rich nuclides through chemical preparation of the sample from fission products for detailed gamma-ray spectroscopy, which would complement the output of on-line isotope separators. With AUTOBATCH the gamma rays following the ..beta../sup -/ decay of /sup 83/As were studied to determine the ground state spin and parity of /sup 83/As to be 5/2/sup -/; the absolute intensity of the ..beta../sup -/ branch from /sup 83/As to /sup 83/Se/sup m/ to be 0.3%; the absolute intensity of the ground state ..beta../sup -/ branch from /sup 83/Se/sup m/ to /sup 83/Br to be 39%; the halflife of the 5/2/sub 1//sup +/ level to be 3.2 ns; and the structure of /sup 83/Se/sub 49/. Results are used to show that the intruder structure which had been previously observed in the odd mass /sub 49/In isotopes could be observed in the N = 49 isotones. The observed structure is discussed in terms of the unified model calculations of Heyde which has been used to describe the intruder structure in the indium nuclei. The intruder structure is most strongly developed, not at core mid-shell, /sup 89/Zr/sub 49/, but rather at core mid-sub-shell /sup 83/Se. This difference is qualitatively understood to be due to the blocking of collectivity by the Z = 40 subshell closure which prevents the intruder structure from occurring in /sup 87/Sr/sub 49/ and /sup 89/Zr/sub 49/.

Lien, O.G. III

1983-10-01T23:59:59.000Z

159

Radiation: Facts, Risks and Realities  

E-Print Network [OSTI]

of Radiation 3 Understanding Radiation Risks 6 Naturally Occurring (Background) Radiation 7 Man-Made Radiation, beta particles and gamma rays. Other types, such as x-rays, can occur naturally or be machine-produced. Scientists have also learned that radiation sources are naturally all around us. Radiation can come from

160

RADIATION SENSITIVITY & PROCESSING OF DNA DAMAGE FOLLOWING LOW DOSES OF GAMMA-RAY ALPHA PARTICLES & HZE IRRADIATION OF NORMAL DSB REPAIR DEFICIENT CELLS  

SciTech Connect (OSTI)

Non-homologous end joining (NHEJ) predominates in the repair of DNA double strand breaks (DSB) over homologous recombination (HR). NHEJ occurs throughout the cell cycle whereas HR occurs in late S/G2 due to the requirement of a sister chromatid (Rothkamm et al, Mol Cell Biol 23 5706-15 [2003]). To date evidence obtained with DSB repair deficient cells using pulsed-field gel electrophoresis has revealed the major pathway throughout all phases of the cell cycle for processing high dose induced DSBs is NHEJ (Wang et al, Oncogene 20 2212-24 (2001); Pluth et al, Cancer Res. 61 2649-55 [2001]). These findings however were obtained at high doses when on average >> 20-30 DSBs are formed per cell. The contribution of the repair pathways (NHEJ and HR) induced in response to DNA damage during the various phases of the cell cycle may depend upon the dose (the level of initial DSBs) especially since low levels of DSBs are induced at low dose. To date, low dose studies using NHEJ and HR deficient mutants have not been carried out to address this important question with radiations of different quality. The work presented here leads us to suggest that HR plays a relatively minor role in the repair of radiation-induced prompt DSBs. SSBs lead to the induction of DSBs which are associated specifically with S-phase cells consistent with the idea that they are formed at stalled replication forks in which HR plays a major role in repair. That DNA-PKcs is in some way involved in the repair of the precursors to replication-induced DSB remains an open question. Persistent non-DSB oxidative damage also leads to an increase in RAD51 positive DSBs. Both simple and complex non-DSB DNA damage may therefore contribute to indirect DSBs induced by ionising radiation at replication forks.

O'Neil, Peter

2009-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Gamma ray camera  

DOE Patents [OSTI]

A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array.

Perez-Mendez, Victor (Berkeley, CA)

1997-01-01T23:59:59.000Z

162

Gamma ray camera  

DOE Patents [OSTI]

A gamma ray camera is disclosed for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array. 6 figs.

Perez-Mendez, V.

1997-01-21T23:59:59.000Z

163

Gamma radiological surveys of the Oak Ridge Reservation, Paducah Gaseous Diffusion Plant, and Portsmouth Gaseous Diffusion Plant, 1990-1993, and overview of data processing and analysis by the Environmental Restoration Remote Sensing Program, Fiscal Year 1995  

SciTech Connect (OSTI)

Three gamma radiological surveys have been conducted under auspices of the ER Remote Sensing Program: (1) Oak Ridge Reservation (ORR) (1992), (2) Clinch River (1992), and (3) Portsmouth Gaseous Diffusion Plant (PORTS) (1993). In addition, the Remote Sensing Program has acquired the results of earlier surveys at Paducah Gaseous Diffusion Plant (PGDP) (1990) and PORTS (1990). These radiological surveys provide data for characterization and long-term monitoring of U.S. Department of Energy (DOE) contamination areas since many of the radioactive materials processed or handled on the ORR, PGDP, and PORTS are direct gamma radiation emitters or have gamma emitting daughter radionuclides. High resolution airborne gamma radiation surveys require a helicopter outfitted with one or two detector pods, a computer-based data acquisition system, and an accurate navigational positioning system for relating collected data to ground location. Sensors measure the ground-level gamma energy spectrum in the 38 to 3,026 KeV range. Analysis can provide gamma emission strength in counts per second for either gross or total man-made gamma emissions. Gross count gamma radiation includes natural background radiation from terrestrial sources (radionuclides present in small amounts in the earth`s soil and bedrock), from radon gas, and from cosmic rays from outer space as well as radiation from man-made radionuclides. Man-made count gamma data include only the portion of the gross count that can be directly attributed to gamma rays from man-made radionuclides. Interpretation of the gamma energy spectra can make possible the determination of which specific radioisotopes contribute to the observed man-made gamma radiation, either as direct or as indirect (i.e., daughter) gamma energy from specific radionuclides (e.g., cesium-137, cobalt-60, uranium-238).

Smyre, J.L.; Moll, B.W.; King, A.L.

1996-06-01T23:59:59.000Z

164

Three-year increase of Gamma-Glutamyl Transferase level and development of type 2 diabetes, in middle-aged men and women: the D.E.S.I.R. cohort.  

E-Print Network [OSTI]

1/13 Three-year increase of Gamma-Glutamyl Transferase level and development of type 2 diabetes and development of Type 2 Diabetes P. André, B. Balkau, C. Born, M. A. Charles, E. Eschwège and the D) is the main predictor for the development of type 2 diabetes, but there is no data on GGT change and type 2

Paris-Sud XI, Université de

165

A new measurement of the rare decay eta -> pi^0 gamma gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron  

SciTech Connect (OSTI)

A new measurement of the rare, doubly radiative decay eta->pi^0 gamma gamma was conducted with the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. New data on the dependence of the partial decay width, Gamma(eta->pi^0 gamma gamma), on the two-photon invariant mass squared, m^2(gamma gamma), as well as a new, more precise value for the decay width, Gamma(eta->pi^0 gamma gamma) = (0.33+/-0.03_tot) eV, are based on analysis of 1.2 x 10^3 eta->pi^0 gamma gamma decays from a total of 6 x 10^7 eta mesons produced in the gamma p -> eta p reaction. The present results for dGamma(eta->pi^0 gamma gamma)/dm^2(gamma gamma) are in good agreement with previous measurements and recent theoretical calculations for this dependence.

Nefkens, B. M.; Prakhov, S.; Aguar-Bartolom??, P.; Annand, J. R.; Arends, H. J.; Bantawa, K.; Beck, R.; Bekrenev, V.; Bergh??user, H.; Braghieri, A.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Codling, R. F.; Collicott, C.; Costanza, S.; Danilkin, I. V.; Denig, A.; Demissie, B.; Dieterle, M.; Downie, E. J.; Drexler, P.; Fil'kov, L. V.; Fix, A.; Garni, S.; Glazier, D. I.; Gregor, R.; Hamilton, D.; Heid, E.; Hornidge, D.; Howdle, D.; Jahn, O.; Jude, T. C.; Kashevarov, V. L.; K??ser, A.; Keshelashvili, I.; Kondratiev, R.; Korolija, M.; Kotulla, M.; Koulbardis, A.; Kruglov, S.; Krusche, B.; Lisin, V.; Livingston, K.; MacGregor, I. J.; Maghrbi, Y.; Mancel, J.; Manley, D. M.; McNicoll, E. F.; Mekterovic, D.; Metag, V.; Mushkarenkov, A.; Nikolaev, A.; Novotny, R.; Oberle, M.; Ortega, H.; Ostrick, M.; Ott, P.; Otte, P. B.; Oussena, B.; Pedroni, P.; Polonski, A.; Robinson, J.; Rosner, G.; Rostomyan, T.; Schumann, S.; Sikora, M. H.; Starostin, A.; Strakovsky, I. I.; Strub, T.; Suarez, I. M.; Supek, I.; Tarbert, C. M.; Thiel, M.; Thomas, A.; Unverzagt, M.; Watts, D. P.; Werthmueller, D; Witthauer, L.

2014-08-01T23:59:59.000Z

166

Impact of Ultrahigh Baseline PSA Levels on Biochemical and Clinical Outcomes in Two Radiation Therapy Oncology Group Prostate Clinical Trials  

SciTech Connect (OSTI)

Purpose: To assess ultrahigh (UH; prostate-specific antigen [PSA]levels {>=}50 ng/ml) patient outcomes by comparison to other high-risk patient outcomes and to identify outcome predictors. Methods and Materials: Prostate cancer patients (PCP) from two Phase III Radiation Therapy Oncology Group clinical trials (studies 9202 and 9413) were divided into two groups: high-risk patients with and without UH baseline PSA levels. Predictive variables included age, Gleason score, clinical T stage, Karnofsky performance score, and treatment arm. Outcomes included overall survival (OS), distant metastasis (DM), and biochemical failure (BF). Unadjusted and adjusted hazard ratios (HRs) were calculated using either the Cox or Fine and Gray's regression model with associated 95% confidence intervals (CI) and p values. Results: There were 401 patients in the UH PSA group and 1,792 patients in the non-UH PSA PCP group of a total of 2,193 high-risk PCP. PCP with UH PSA were found to have inferior OS (HR, 1.19; 95% CI, 1.02-1.39, p = 0.02), DM (HR, 1.51; 95% CI, 1.19-1.92; p = 0.0006), and BF (HR, 1.50; 95% CI, 1.29-1.73; p < 0.0001) compared to other high-risk PCP. In the UH cohort, PSA level was found to be a significant factor for the risk of DM (HR, 1.01; 95% CI, 1.001-1.02) but not OS and BF. Gleason grades of 8 to 10 were found to consistently predict for poor OS, DM, and BF outcomes (with HR estimates ranging from 1.41-2.36) in both the high-risk cohort and the UH cohort multivariable analyses. Conclusions: UH PSA levels at diagnosis are related to detrimental changes in OS, DM, and BF. All three outcomes can be modeled by various combinations of all predictive variables tested.

Rodrigues, George, E-mail: george.rodrigues@lhsc.on.c [Department of Oncology, University of Western Ontario, London, Ontario (Canada); Bae, Kyounghwa [Department of Statistics, Radiation Therapy Oncology Group, Philadelphia, Pennsylvania (United States); Roach, Mack [Department of Radiation Oncology, University of California San Francisco, San Francisco, California (United States); Lawton, Colleen [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Donnelly, Bryan [Department of Surgical Oncology, University of Calgary, Calgary, Alberta (Canada); Grignon, David [Department of Pathology, Indiana Pathology Institute, Indianapolis, Indiana (United States); Hanks, Gerald [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Porter, Arthur [Department of Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Lepor, Herbert [Department of Urology, NY University Langone Medical Center, New York, New York (United States); Sandler, Howard [Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California (United States)

2011-06-01T23:59:59.000Z

167

The frequency of tropopause-level thick and thin cirrus clouds as observed by CALIPSO and the relationship to relative humidity and outgoing longwave radiation  

E-Print Network [OSTI]

schematic of the location of the SPCZ and the ITCZ in the Pacific Ocean................................................... 40 3 Three month average of outgoing longwave radiation (OLR) for DJF provided by the NOAA/OAR/ESRL PSD... THE FREQUENCY OF TROPOPAUSE-LEVEL THICK AND THIN CIRRUS CLOUDS AS OBSERVED BY CALIPSO AND THE RELATIONSHIP TO RELATIVE HUMIDITY AND OUTGOING LONGWAVE RADIATION A Thesis by ALLISON L. CARDONA Submitted to the Office of Graduate...

Cardona, Allison Leanne

2008-10-10T23:59:59.000Z

168

Plutonium radiation surrogate  

DOE Patents [OSTI]

A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little .alpha.-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.

Frank, Michael I. (Dublin, CA)

2010-02-02T23:59:59.000Z

169

Cros S., Wald L., 2003. Survey of the main databases providing solar radiation data at ground level. In Proceedings of the 23rd EARSeL Annual Symposium "Remote Sensing in Transition", 2-4 June 2003, Ghent,  

E-Print Network [OSTI]

Cros S., Wald L., 2003. Survey of the main databases providing solar radiation data at ground level providing solar radiation data at the ground level S. Cros & L. Wald Remote Sensing and Modeling Group, Ecole des Mines de Paris, France Keywords: solar radiation, database, information system, climatology

Paris-Sud XI, Université de

170

Real-Time Optical Flux Limits From Gamma-Ray Bursts Measured By The GROCSE Experiment  

E-Print Network [OSTI]

The Gamma-Ray Optical Counterpart Search Experiment (GROCSE) presents new experimental upper limits on the optical flux from gamma-ray bursts (GRBs). Our experiment consisted of a fully-automated very wide-field opto-electronic detection system that imaged locations of GRBs within a few seconds of receiving trigger signals provided by BATSE's real-time burst coordinate distribution network (BACODINE). The experiment acquired ~3800 observing hours, recording 22 gamma-ray burst triggers within $\\sim$30 s of the start of the burst event. Some of these bursts were imaged while gamma-ray radiation was being detected by BATSE. We identified no optical counterparts associated with gamma-ray bursts amongst these events at the m$_V$ $\\sim$ 7.0 to 8.5 sensitivity level. We find the ratio of the upper limit to the V-band optical flux, F$_\

H. S. Park; E. Ables; D. L. Band; S. D. Barthelmy; R. M. Bionta; P. S. Butterworth; T. L. Cline; D. H. Ferguson; G. J. Fishman; N. Gehrels; K. Hurley; C. Kouveliotou; B. C. Lee; C. A. Meegan; L. L. Ott; E. L. Parker

1997-02-28T23:59:59.000Z

171

Statistical correlation between hourly and daily values of solar radiation on horizontal surface at sea level in the Italian climate  

E-Print Network [OSTI]

219- Statistical correlation between hourly and daily values of solar radiation on horizontal- nalières du rayonnement solaire. Abstract. 2014 The knowledge of hourly data of solar radiation is required data measured in Italian stations and propose a method to estimate hourly solar radiation

Boyer, Edmond

172

Radiative Decays of the B Meson  

SciTech Connect (OSTI)

The radiative decays of the B meson to the final states K *(892){gamma} and {rho}(770){gamma} proceed through virtual effective flavor-changing neutral current processes which are sensitive to contributions from high mass scales from within the Standard Model of particle interactions and from possible new physics. In the context of the Standard Model, these transitions are of interest in probing the weak interaction behavior of the top quark. In particular, the ratio of branching fractions for the two processes can be used to extract the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |V{sub td}/V{sub ts}|. Potential new physics contributions in these virtual transitions may induce new sources of direct CP violation and enhancement or suppression of the rate of these processes. The B {yields} K*{gamma} is a manifestation of the b {yields} s{gamma} radiative transition. This process has been previously observed by the CLEO collaboration and its branching fraction measured. While the theoretical prediction for the inclusive rate of b {yields} s{gamma} transitions is more robust than that of the exclusive B {yields} K*{gamma}, the prospects for precise measurements of {Beta}[B {yields} K*{gamma}] and direct CP violation in this channel has attracted considerable attention. The analysis described here represents an improved measurement of the B {yields} K*{gamma} branching factions and a more sensitive search for direct CP violation. In 22.7 x 10{sup 6} B{bar B} events collected by the BABAR detector in 1999-2000, we measure: {Beta}[B{sup 0} {yields} K*{sup 0}{gamma}] = 4.23 {+-} 0.40(stat.) {+-} 0.22(syst.) x 10{sup -5} and {Beta}[B{sup +} {yields} K*{sup +}{gamma}] = 3.83 {+-} 0.62(stat.) {+-} 0.22(syst.) x 10{sup -5}. We find no evidence for direct CP violation in the decays and constrain -0.170 < A{sub CP} < 0.082 at 90% Confidence Level. The B {yields} {rho}{gamma} proceeds through the analogous b {yields} d{gamma} radiative transition. As such, its rate is suppressed by a factor of |V{sub td}/V{sub ts}|{sup 2} {approx} {Omicron}(50) relative to B {yields} K*{gamma} and remains unobserved. Current limits on the branching fractions of B {yields} {rho}{gamma} are still an order of magnitude above the theoretical predictions. While the uncertainty in the theoretical predictions for the branching fraction of this mode are large, it may be possible to reduce these uncertainties by considering the ratio of the branching fractions for B {yields} {rho}{gamma} and B {yields} K*{gamma} which would lead to a measurement of |V{sub td}/V{sub ts}|. The analysis presented here represents a search with nearly an order of magnitude more data and new analysis techniques. In a sample of 61 .7 x 10{sup 6} B{bar B} events, we find no significant evidence for the decay B {yields} {rho}{gamma} is and establish the following 90% Confidence Level upper limits on the branching fraction: {Beta}[B{sup 0} {yields} {rho}{sup 0}{gamma}] < 1.5 x 10{sup -6} and {Beta}[B{sup +} {yields} {rho}{sup +}{gamma}] < 2.8 x 10{sup -6}.

Tanaka, Hirohisa A

2003-09-23T23:59:59.000Z

173

Radiation and Background Levels in a CLIC Detector due to Beam-Beam Effects Optimisation of Detector Geometries and Technologies  

E-Print Network [OSTI]

The high charge density---due to small beam sizes---and the high energy of the proposed CLIC concept for a linear electron--positron collider with a centre-of-mass energy of up to 3~TeV lead to the production of a large number of particles through beam-beam interactions at the interaction point during every bunch crossing (BX). A large fraction of these particles safely leaves the detector. A still significant amount of energy will be deposited in the forward region nonetheless, which will produce secondary particles able to cause background in the detector. Furthermore, some particles will be created with large polar angles and directly cause background in the tracking detectors and calorimeters. The main sources of background in the detector, either directly or indirectly, are the incoherent $mathrm{e}^{+}mathrm{e}^{-}$ pairs and the particles from $gammagamma ightarrow$ hadron events. The background and radiation levels in the detector have to be estimated, to study if a detector is feasible, that can han...

Sailer, André; Lohse, Thomas

2013-01-10T23:59:59.000Z

174

Observations of Gamma-Ray Burst Afterglows with the AEOS Burst Camera.  

E-Print Network [OSTI]

??Gamma-ray bursts (GRBs), are variable bursts of gamma-ray radiation, that lasts from milliseconds to hundreds of seconds. These bursts of gamma rays are detected in… (more)

Flewelling, Heather Anne

2009-01-01T23:59:59.000Z

175

Radiation Processing -an overview  

E-Print Network [OSTI]

of radiation · Facilities ­ Gamma ­ electrons ­ X-ray ­ Safety · Sterilisation of medical devices · Food irradiation · Material modification #12;3 Content ­ Part 2 · Environmental applications · Other applications Radiation · Energy in the form of waves or moving subatomic particles Irradiation · Exposure to radiation

176

Composition for radiation shielding  

DOE Patents [OSTI]

A composition for use as a radiation shield. The shield has a depleted urum core for absorbing gamma rays and a bismuth coating for preventing chemical corrosion and absorbing gamma rays. Alternatively, a sheet of gadolinium may be positioned between the uranium core and the bismuth coating for absorbing neutrons. The composition is preferably in the form of a container for storing materials that emit radiation such as gamma rays and neutrons. The container is preferably formed by casting bismuth around a pre-formed uranium container having a gadolinium sheeting, and allowing the bismuth to cool. The resulting container is a structurally sound, corrosion-resistant, radiation-absorbing container.

Kronberg, James W. (Aiken, SC)

1994-01-01T23:59:59.000Z

177

The neutron-gamma Feynman variance to mean approach: gamma detection and total neutron-gamma detection (theory and practice)  

E-Print Network [OSTI]

Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have a particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron-gamma detector at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with inclusion of general reactions and passage intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source enclosed in a steel container. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma, are evaluated experimentally for a weak 252Cf neutron-gamma source in a steel container, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-Y formulas.

Dina Chernikova; Kåre Axell; Senada Avdic; Imre Pázsit; Anders Nordlund

2015-01-23T23:59:59.000Z

178

Environmental radiation data report 73, January-March 1993. Quarterly report  

SciTech Connect (OSTI)

Environmental Radiation Data (ERD) contains data from the Environmental Radiation Ambients Monitoring System (ERAMS). The ERAMS is comprised of nationwide sampling stations that provide air, surface and drinking water and milk samples from which environmental radiation levels are derived. Sampling locations are selected to provide optimal population coverage while functioning to monitor fallout from nuclear devices and other forms of radioactive contamination of the environment. The radiation analyses performed on these samples include gross alpha and gross beta levels, gamma analyses for fission products, and specific analyses for uranium, plutonium, strontium, iodine, radium, krypton, and tritium.

Not Available

1993-10-01T23:59:59.000Z

179

Lefvre M., Cros S., Albuisson M., Wald L., 2003. Developing a database using Meteosat data for the de-livery of solar radiation assessments at ground level. In Proceedings of the 23rd EARSeL Annual Symposium  

E-Print Network [OSTI]

for the de- livery of solar radiation assessments at ground level. In Proceedings of the 23rd EARSeL Annual, Meteosat, solar radiation, climatology, database, information system ABSTRACT: An information system, called HelioClim, is offered for answering the needs for long-term time-series of solar radiation data

Paris-Sud XI, Université de

180

Radiation detector  

DOE Patents [OSTI]

Apparatus is provided for detecting radiation such as gamma rays and X-rays generated in backscatter Mossbauer effect spectroscopy and X-ray spectrometry, which has a large "window" for detecting radiation emanating over a wide solid angle from a specimen and which generates substantially the same output pulse height for monoenergetic radiation that passes through any portion of the detection chamber. The apparatus includes a substantially toroidal chamber with conductive walls forming a cathode, and a wire anode extending in a circle within the chamber with the anode lying closer to the inner side of the toroid which has the least diameter than to the outer side. The placement of the anode produces an electric field, in a region close to the anode, which has substantially the same gradient in all directions extending radially from the anode, so that the number of avalanche electrons generated by ionizing radiation is independent of the path of the radiation through the chamber.

Fultz, Brent T. (Berkeley, CA)

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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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181

Radiation detector  

DOE Patents [OSTI]

Apparatus is provided for detecting radiation such as gamma rays and x-rays generated in backscatter Moessbauer effect spectroscopy and x-ray spectrometry, which has a large window for detecting radiation emanating over a wide solid angle from a specimen and which generates substantially the same output pulse height for monoenergetic radiation that passes through any portion of the detection chamber. The apparatus includes a substantially toroidal chamber with conductive walls forming a cathode, and a wire anode extending in a circle within the chamber with the anode lying closer to the inner side of the toroid which has the least diameter than to the outer side. The placement of the anode produces an electric field, in a region close to the anode, which has substantially the same gradient in all directions extending radially from the anode, so that the number of avalanche electrons generated by ionizing radiation is independent of the path of the radiation through the chamber.

Fultz, B.T.

1980-12-05T23:59:59.000Z

182

Radiation Transport Simulation Studies Using MCNP for a Cow Phantom to Determine an Optimal Detector Configuration for a New Livestock Portal  

E-Print Network [OSTI]

scalable gamma radiation portal monitor (RPM) which can be used to assess the level of contamination on large animals like cattle. This work employed a Monte Carlo N-Particle (MCNP) radiation transport code for the purpose. A virtual system of cow...

Joe Justina, -

2012-10-19T23:59:59.000Z

183

X-RAYRICH GAMMA-RAY BURSTS, PHOTOSPHERES, AND VARIABILITY P. Meszaros,1,2  

E-Print Network [OSTI]

X-RAY­RICH GAMMA-RAY BURSTS, PHOTOSPHERES, AND VARIABILITY P. Me´sza´ros,1,2 E. Ramirez-Ruiz,3 M. J of the observational gamma-ray variability-luminosity relation. Subject headings: gamma rays: bursts -- radiation mechanisms: nonthermal 1. INTRODUCTION Gamma-ray burst (GRB) light curves at gamma-ray ener- gies are often

Zhang, Bing

184

Estimating the risks of cancer mortality and genetic defects resulting from exposures to low levels of ionizing radiation  

SciTech Connect (OSTI)

Estimators for calculating the risk of cancer and genetic disorders induced by exposure to ionizing radiation have been recommended by the US National Academy of Sciences Committee on the Biological Effects of Ionizing Radiations, the UN Scientific Committee on the Effects of Atomic Radiation, and the International Committee on Radiological Protection. These groups have also considered the risks of somatic effects other than cancer. The US National Council on Radiation Protection and Measurements has discussed risk estimate procedures for radiation-induced health effects. The recommendations of these national and international advisory committees are summarized and compared in this report. Based on this review, two procedures for risk estimation are presented for use in radiological assessments performed by the US Department of Energy under the National Environmental Policy Act of 1969 (NEPA). In the first procedure, age- and sex-averaged risk estimators calculated with US average demographic statistics would be used with estimates of radiation dose to calculate the projected risk of cancer and genetic disorders that would result from the operation being reviewed under NEPA. If more site-specific risk estimators are needed, and the demographic information is available, a second procedure is described that would involve direct calculation of the risk estimators using recommended risk-rate factors. The computer program REPCAL has been written to perform this calculation and is described in this report. 25 references, 16 tables.

Buhl, T.E.; Hansen, W.R.

1984-05-01T23:59:59.000Z

185

Cellular and molecular research to reduce uncertainties in estimates of health effects from low-level radiation  

SciTech Connect (OSTI)

A study was undertaken by five radiation scientists to examine the feasibility of reducing the uncertainties in the estimation of risk due to protracted low doses of ionizing radiation. In addressing the question of feasibility, a review was made by the study group: of the cellular, molecular, and mammalian radiation data that are available; of the way in which altered oncogene properties could be involved in the loss of growth control that culminates in tumorigenesis; and of the progress that had been made in the genetic characterizations of several human and animal neoplasms. On the basis of this analysis, the study group concluded that, at the present time, it is feasible to mount a program of radiation research directed at the mechanism(s) of radiation-induced cancer with special reference to risk of neoplasia due to protracted, low doses of sparsely ionizing radiation. To implement a program of research, a review was made of the methods, techniques, and instruments that would be needed. This review was followed by a survey of the laboratories and institutions where scientific personnel and facilities are known to be available. A research agenda of the principal and broad objectives of the program is also discussed. 489 refs., 21 figs., 14 tabs.

Elkind, M.M.; Bedford, J.; Benjamin, S.A.; Waldren, C.A. (Colorado State Univ., Fort Collins, CO (USA)); Gotchy, R.L. (Science Applications International Corp., McLean, VA (USA))

1990-10-01T23:59:59.000Z

186

Patient radiation doses in interventional cardiology in the U.S.: Advisory data sets and possible initial values for U.S. reference levels  

SciTech Connect (OSTI)

Purpose: To determine patient radiation doses from interventional cardiology procedures in the U.S and to suggest possible initial values for U.S. benchmarks for patient radiation dose from selected interventional cardiology procedures [fluoroscopically guided diagnostic cardiac catheterization and percutaneous coronary intervention (PCI)]. Methods: Patient radiation dose metrics were derived from analysis of data from the 2008 to 2009 Nationwide Evaluation of X-ray Trends (NEXT) survey of cardiac catheterization. This analysis used deidentified data and did not require review by an IRB. Data from 171 facilities in 30 states were analyzed. The distributions (percentiles) of radiation dose metrics were determined for diagnostic cardiac catheterizations, PCI, and combined diagnostic and PCI procedures. Confidence intervals for these dose distributions were determined using bootstrap resampling. Results: Percentile distributions (advisory data sets) and possible preliminary U.S. reference levels (based on the 75th percentile of the dose distributions) are provided for cumulative air kerma at the reference point (K{sub a,r}), cumulative air kerma-area product (P{sub KA}), fluoroscopy time, and number of cine runs. Dose distributions are sufficiently detailed to permit dose audits as described in National Council on Radiation Protection and Measurements Report No. 168. Fluoroscopy times are consistent with those observed in European studies, but P{sub KA} is higher in the U.S. Conclusions: Sufficient data exist to suggest possible initial benchmarks for patient radiation dose for certain interventional cardiology procedures in the U.S. Our data suggest that patient radiation dose in these procedures is not optimized in U.S. practice.

Miller, Donald L.; Hilohi, C. Michael; Spelic, David C. [Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States)

2012-10-15T23:59:59.000Z

187

CRYOPUMP BEHAVIOR IN THE PRESENCE OF BEAM OR NUCLEAR RADIATION  

E-Print Network [OSTI]

Reactor Experiment In order to ascertain the effect of fast neutrons and gamma radiation on the absorbed deuterium gas

Law, P.K.

2011-01-01T23:59:59.000Z

188

Gamma ray optics  

SciTech Connect (OSTI)

Via refractive or diffractive scattering one can shape {gamma} ray beams in terms of beam divergence, spot size and monochromaticity. These concepts might be particular important in combination with future highly brilliant gamma ray sources and might push the sensibility of planned experiments by several orders of magnitude. We will demonstrate the experimental feasibility of gamma ray monochromatization on a ppm level and the creation of a gamma ray beam with nanoradian divergence. The results are obtained using the inpile target position of the High Flux Reactor of the ILL Grenoble and the crystal spectrometer GAMS. Since the refractive index is believed to vanish to zero with 1/E{sup 2}, the concept of refractive optics has never been considered for gamma rays. The combination of refractive optics with monochromator crystals is proposed to be a promising design. Using the crystal spectrometer GAMS, we have measured for the first time the refractive index at energies in the energy range of 180 - 2000 keV. The results indicate a deviation from simple 1/E{sup 2} extrapolation of X-ray results towards higher energies. A first interpretation of these new results will be presented. We will discuss the consequences of these results on the construction of refractive optics such as lenses or refracting prisms for gamma rays and their combination with single crystal monochromators.

Jentschel, M.; Guenther, M. M.; Habs, D.; Thirolf, P. G. [Institut Laue-Langevin, F38042 Grenoble (France); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching, Germany and Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany)

2012-07-09T23:59:59.000Z

189

Common Origin of 3.55 keV X-Ray Line and Galactic Center Gamma Ray Excess in a Radiative Neutrino Mass Model  

E-Print Network [OSTI]

We attempt to simultaneously explain the recently observed 3.55 keV X-ray line in the analysis of XMM-Newton telescope data and the galactic center gamma ray excess observed by the Fermi gamma ray space telescope within an abelian gauge extension of standard model. We consider a two component dark matter scenario with a mass difference 3.55 keV such that the heavier one can decay into the lighter one and a photon with energy 3.55 keV. The lighter dark matter candidate is protected from decaying into the standard model particles by a remnant $Z_2$ symmetry into which the abelian gauge symmetry gets spontaneously broken. If the mass of the dark matter particle is chosen to be within $31-40$ GeV, then this model can also explain the galactic center gamma ray excess if the dark matter annihilation into $b\\bar{b}$ pairs has a cross section of $\\langle \\sigma v \\rangle \\simeq (1.4-2.0) \\times 10^{-26} \\; \\text{cm}^3/\\text{s}$. We constrain the model from the requirement of producing correct dark matter relic densit...

Borah, Debasish; Adhikari, Rathin

2015-01-01T23:59:59.000Z

190

Curcumin Regulates Low-Linear Energy Transfer {gamma}-Radiation-Induced NF{kappa}B-Dependent Telomerase Activity in Human Neuroblastoma Cells  

SciTech Connect (OSTI)

Purpose: We recently reported that curcumin attenuates ionizing radiation (IR)-induced survival signaling and proliferation in human neuroblastoma cells. Also, in the endothelial system, we have demonstrated that NF{kappa}B regulates IR-induced telomerase activity (TA). Accordingly, we investigated the effect of curcumin in inhibiting IR-induced NF{kappa}B-dependent hTERT transcription, TA, and cell survival in neuroblastoma cells. Methods and Materials: SK-N-MC or SH-SY5Y cells exposed to IR and treated with curcumin (10-100 nM) with or without IR were harvested after 1 h through 24 h. NF{kappa}B-dependent regulation was investigated either by luciferase reporter assays using pNF{kappa}B-, pGL3-354-, pGL3-347-, or pUSE-I{kappa}B{alpha}-Luc, p50/p65, or RelA siRNA-transfected cells. NF{kappa}B activity was analyzed using an electrophoretic mobility shift assay and hTERT expression using the quantitative polymerase chain reaction. TA was determined using the telomerase repeat amplification protocol assay and cell survival using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltertrazolium bromide and clonogenic assay. Results: Curcumin profoundly inhibited IR-induced NF{kappa}B. Consequently, curcumin significantly inhibited IR-induced TA and hTERT mRNA at all points investigated. Furthermore, IR-induced TA is regulated at the transcriptional level by triggering telomerase reverse transcriptase (TERT) promoter activation. Moreover, NF{kappa}B becomes functionally activated after IR and mediates TA upregulation by binding to the {kappa}B-binding region in the promoter region of the TERT gene. Consistently, elimination of the NF{kappa}B-recognition site on the telomerase promoter or inhibition of NF{kappa}B by the I{kappa}B{alpha} mutant compromises IR-induced telomerase promoter activation. Significantly, curcumin inhibited IR-induced TERT transcription. Consequently, curcumin inhibited hTERT mRNA and TA in NF{kappa}B overexpressed cells. Furthermore, curcumin enhanced the IR-induced inhibition of cell survival. Conclusions: These results strongly suggest that curcumin inhibits IR-induced TA in an NF{kappa}B dependent manner in human neuroblastoma cells.

Aravindan, Natarajan, E-mail: naravind@ouhsc.ed [Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Veeraraghavan, Jamunarani; Madhusoodhanan, Rakhesh; Herman, Terence S. [Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Natarajan, Mohan [Department of Otolaryngology, Head and Neck Surgery, University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States)

2011-03-15T23:59:59.000Z

191

Astrophysical S factor for the radiative capture (12)N(p,gamma)(13)O determined from the (14)N((12)N,(13)O)(13)C proton transfer reaction  

E-Print Network [OSTI]

The cross section of the radiative proton capture reaction on the drip line nucleus (12)N was investigated using the asymptotic normalization coefficient (ANC) method. We have used the (14)N((12)N,(13)O)(13)C proton transfer reaction at 12 Me...

Banu, A.; Al-Abdullah, T.; Fu, C.; Gagliardi, Carl A.; McCleskey, M.; Mukhamedzhanov, A. M.; Tabacaru, G.; Trache, L.; Tribble, Robert E.; Zhai, Y.; Carstoiu, F.; Burjan, V.; Kroha, V.

2009-01-01T23:59:59.000Z

192

Environmental radiation data report 80, October-December 1994. Final report  

SciTech Connect (OSTI)

Environmental Radiation Data (ERD) contains data from the Environmental Radiation Ambient Monitoring System (ERAMS). Sampling locations are selected to provide optimal population coverage while functioning to monitor fallout from nuclear devices and other forms of radioactive contamination of the environment. The radiation analyses performed on these samples include gross alpha and gross beta levels, gamma analyses for fission products, and specific analyses for uranium, plutonium, stronthium, iodine, radium, and tritium. This monitoring effort also provides ancillary information on natural background levels and on routine and accidental releases into the environment from stationary sources.

NONE

1997-02-01T23:59:59.000Z

193

Environmental radiation data report 79, July-September 1994. Final report  

SciTech Connect (OSTI)

Environmental Radiation Data (ERD) contains data from the Environmental Radiation Ambient Monitoring System (ERAMS). Sampling locations are selected to provide optimal population coverage while functioning to monitor fallout from nuclear devices and other forms of radioactive contamination of the environment. The radiation analyses performed on these samples include gross alpha and gross beta levels, gamma analyses for fission products, and specific analyses for uranium, plutonium, stronthium, iodine, radium, and tritium. This monitoring effort also provides ancillary information on natural background levels and on routine and accidental releases into the environment from stationary sources.

NONE

1997-02-01T23:59:59.000Z

194

Environmental radiation data report 81, January-March 1995. Final report  

SciTech Connect (OSTI)

Environmental Radiation Data (ERD) contains data from the Environmental Radiation Ambient Monitoring System (ERAMS). Sampling locations are selected to provide optimal population coverage while functioning to monitor fallout from nuclear devices and other forms of radioactive contamination of the environment. The radiation analyses performed on these samples include gross alpha and gross beta levels, gamma analyses for fission products, and specific analyses for uranium, plutonium, stronthium, iodine, radium, and tritium. This monitoring effort also provides ancillary information on natural background levels and on routine and accidental releases into the environment from stationary sources.

NONE

1997-02-01T23:59:59.000Z

195

Environmental radiation data report 82, April-June 1995. Final report  

SciTech Connect (OSTI)

Environmental Radiation Data (ERD) contains data from the Environmental Radiation Ambient Monitoring System (ERAMS). Sampling locations are selected to provide optimal population coverage while functioning to monitor fallout from nuclear devices and other forms of radioactive contamination of the environment. The radiation analyses performed on these samples include gross alpha and gross beta levels, gamma analyses for fission products, and specific analyses for uranium, plutonium, stronthium, iodine, radium, and tritium. This monitoring effort also provides ancillary information on natural background levels and on routine and accidental releases into the environment from stationary sources.

NONE

1997-02-01T23:59:59.000Z

196

High resistivity aluminum antimonide radiation detector  

DOE Patents [OSTI]

Bulk Aluminum Antimonide (AlSb)-based single crystal materials have been prepared for use as ambient (room) temperature X-ray and Gamma-ray radiation detection.

Sherohman, John W. (Livermore, CA); Coombs, III, Arthur W. (Patterson, CA); Yee, Jick H. (Livermore, CA)

2007-12-18T23:59:59.000Z

197

Radiation site cleanup regulations: Technical support document for the development of radionuclide cleanup levels for soil. Review draft  

SciTech Connect (OSTI)

This report presents EPA`s approach to assessing some of the beneficial and adverse radiation health effects associated with various possible values for an annual dose limit. In particular, it discusses the method developed to determine how the choice of cleanup criterion affects (1) the time-integrated numbers of non-fatal and fatal radiogenic cancers averted among future populations, (2) the occurrence of radiogenic cancers among remediation workers and the public caused by the cleanup process itself, and (3) the volume of contaminated soil that may require remediation.

Wolbarst, A.B.; Mauro, J.; Anigstein, R.; Back, D.; Bartlett, J.W.

1994-09-24T23:59:59.000Z

198

Disturbance of DKK1 level is partly involved in survival of lung cancer cells via regulation of ROMO1 and ?-radiation sensitivity  

SciTech Connect (OSTI)

Highlights: •DKK1 was expressed differently among non-small-cell lung cancer cell lines. •DKK1 negatively regulated ROMO1 gene expression. •Disturbance of DKK1 level induced the imbalance of cellular ROS. •DKK1/ROMO1-induced ROS imbalance is involved in cell survival in NSCLC. -- Abstract: Dickkopf1 (DKK1), a secreted protein involved in embryonic development, is a potent inhibitor of the Wnt signaling pathway and has been postulated to be a tumor suppressor or tumor promoter depending on the tumor type. In this study, we showed that DKK1 was expressed differently among non-small-cell lung cancer cell lines. The DKK1 expression level was much higher in A549 cells than in H460 cells. We revealed that blockage of DKK1 expression by silencing RNA in A549 cells caused up-regulation of intracellular reactive oxygen species (ROS) modulator (ROMO1) protein, followed by partial cell death, cell growth inhibition, and loss of epithelial–mesenchymal transition property caused by ROS, and it also increased ?-radiation sensitivity. DKK1 overexpression in H460 significantly inhibited cell survival with the decrease of ROMO1 level, which induced the decrease of cellular ROS. Thereafter, exogenous N-acetylcysteine, an antioxidant, or hydrogen peroxide, a pro-oxidant, partially rescued cells from death and growth inhibition. In each cell line, both overexpression and blockage of DKK1 not only elevated p-RB activation, which led to cell growth arrest, but also inactivated AKT/NF-kB, which increased radiation sensitivity and inhibited cell growth. This study is the first to demonstrate that strict modulation of DKK1 expression in different cell types partially maintains cell survival via tight regulation of the ROS-producing ROMO1 and radiation resistance.

Kim, In Gyu, E-mail: igkim@kaeri.re.kr [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of); Department of Radiation Biotechnology and Applied Radioisotope, University of Science and Technology (UST), 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Seo Yoen [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of) [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of); Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806 (Korea, Republic of); Kim, Hyun A; Kim, Jeong Yul [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of)] [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of); Lee, Jae Ha; Choi, Soo Im [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of) [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of); Department of Radiation Biotechnology and Applied Radioisotope, University of Science and Technology (UST), 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Han, Jeong Ran; Kim, Kug Chan [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of)] [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon 305-600 (Korea, Republic of); Cho, Eun Wie [Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806 (Korea, Republic of)] [Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806 (Korea, Republic of)

2014-01-03T23:59:59.000Z

199

Gamma radiolysis of chlorinated hydrocarbons  

SciTech Connect (OSTI)

This program is the Idaho National Engineering Laboratory (INEL) component of a joint collarborative effort with Lawrence Livermore National Laboratory (LLNL). The purpose of this effort is to demonstrate a viable process for breaking down hazardous halogenated organic wastes to simpler, non-hazardous waste using high energy ionizing radiation. The INEL effort focuses on the use of spent reactor fuel gamma radiation sources to decompose complex wastes such as PCBs. At LLNL, halogenated solvents such as carbon tetrachloride and trichloroethylene are being studied using accelerator radiation sources. The INEL irradiation experiments concentrated on a single PCB congener so that a limited set of decomposition reactions could be studied. The congener 2,2{prime}, 3,3{prime},4,5{prime},6,6{prime} - octachlorobiphenyl was examined following exposure to various gamma doses at the Advanced Test Reactor (AIR) spent fuel pool. The decomposition rates and products in several solvents are discussed. 3 refs.

Arbon, R.E.; Mincher, B.J.; Meikrantz, D.H.

1992-01-01T23:59:59.000Z

200

Gamma radiolysis of chlorinated hydrocarbons  

SciTech Connect (OSTI)

This program is the Idaho National Engineering Laboratory (INEL) component of a joint collarborative effort with Lawrence Livermore National Laboratory (LLNL). The purpose of this effort is to demonstrate a viable process for breaking down hazardous halogenated organic wastes to simpler, non-hazardous waste using high energy ionizing radiation. The INEL effort focuses on the use of spent reactor fuel gamma radiation sources to decompose complex wastes such as PCBs. At LLNL, halogenated solvents such as carbon tetrachloride and trichloroethylene are being studied using accelerator radiation sources. The INEL irradiation experiments concentrated on a single PCB congener so that a limited set of decomposition reactions could be studied. The congener 2,2{prime}, 3,3{prime},4,5{prime},6,6{prime} - octachlorobiphenyl was examined following exposure to various gamma doses at the Advanced Test Reactor (AIR) spent fuel pool. The decomposition rates and products in several solvents are discussed. 3 refs.

Arbon, R.E.; Mincher, B.J.; Meikrantz, D.H.

1992-08-01T23:59:59.000Z

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


201

Quality assurance for gamma knives  

SciTech Connect (OSTI)

This report describes and summarizes the results of a quality assurance (QA) study of the Gamma Knife, a nuclear medical device used for the gamma irradiation of intracranial lesions. Focus was on the physical aspects of QA and did not address issues that are essentially medical, such as patient selection or prescription of dose. A risk-based QA assessment approach was used. Sample programs for quality control and assurance are included. The use of the Gamma Knife was found to conform to existing standards and guidelines concerning radiation safety and quality control of external beam therapies (shielding, safety reviews, radiation surveys, interlock systems, exposure monitoring, good medical physics practices, etc.) and to be compliant with NRC teletherapy regulations. There are, however, current practices for the Gamma Knife not covered by existing, formalized regulations, standards, or guidelines. These practices have been adopted by Gamma Knife users and continue to be developed with further experience. Some of these have appeared in publications or presentations and are slowly finding their way into recommendations of professional organizations.

Jones, E.D.; Banks, W.W.; Fischer, L.E. [Lawrence Livermore National Lab., CA (United States)

1995-09-01T23:59:59.000Z

202

INSTALLATION OF A POST-ACCIDENT CONFINEMENT HIGH-LEVEL RADIATION MONITORING SYSTEM IN THE KOLA NUCLEAR POWER STATION (UNIT 2) IN RUSSIA  

SciTech Connect (OSTI)

This is the final report on the INSP project entitled, ``Post-Accident Confinement High-Level Radiation Monitoring System'' conducted by BNL under the authorization of Project Work Plan WBS 1.2.2.6 (Attachment 1). This project was initiated in February 1993 to assist the Russians in reducing risks associated with the continued operation of older Soviet-designed nuclear power plants, specifically the Kola VVER-440/230 Unit 2, through improved accident detection capability, specifically by the installation of a dual train high-level radiation detection system in the confinement of Unit 2 of the Kola NPP. The major technical objective of this project was to provide, install and make operational the necessary hardware inside the confinement of the Kola NPP Unit 2 to provide early and reliable warning of the release of radionuclides from the reactor into the confinement air space as an indication of the occurrence of a severe accident at the plant. In addition, it was intended to provide hands-on experience and training to the Russian plant workers in the installation, operation, calibration and maintenance of the equipment in order that they may use the equipment without continued US assistance as an effective measure to improve reactor safety at the plant.

GREENE,G.A.; GUPPY,J.G.

1998-09-01T23:59:59.000Z

203

Solar irradiance changes and photobiological effects at Earth's surface following astrophysical ionizing radiation events  

E-Print Network [OSTI]

Astrophysical ionizing radiation events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in surface-level solar ultraviolet radiation. Simulations of the atmospheric effects of a variety of events (such as supernovae, gamma-ray bursts, and solar proton events) have been previously published, along with estimates of biological damage at Earth's surface. In this work, we employed the TUV radiative transfer model to expand and improve calculations of surface-level irradiance and biological impacts following an ionizing radiation event. We considered changes in surface-level UVB, UVA, and photosynthetically active radiation (visible light) for clear-sky conditions and fixed aerosol parameter values. We also considered a wide range of biological effects on organisms ranging from humans to phytoplankton. We found that past work overestimated UVB irradiance, but that relative estimates for increase in exposure to DNA damaging radi...

Thomas, Brian C; Snyder, Brock R

2015-01-01T23:59:59.000Z

204

Energy levels, oscillator strengths, and radiative rates for Si-like Zn XVII, Ga XVIII, Ge XIX, and As XX  

SciTech Connect (OSTI)

The energy levels, oscillator strengths, line strengths, and transition probabilities for transitions among the terms belonging to the 3s{sup 2}3p{sup 2}, 3s3p{sup 3}, 3s{sup 2}3p3d, 3s{sup 2}3p4s, 3s{sup 2}3p4p and 3s{sup 2}3p4d configurations of silicon-like ions (Zn XVII, Ga XVIII, Ge XIX, and As XX) have been calculated using the configuration-interaction code CIV3. The calculations have been carried out in the intermediate coupling scheme using the Breit–Pauli Hamiltonian. The present calculations have been compared with the available experimental data and other theoretical calculations. Most of our calculations of energy levels and oscillator strengths (in length form) show good agreement with both experimental and theoretical data. Lifetimes of the excited levels have also been calculated. -- Highlights: •We have calculated the fine-structure energy levels of Si-like Zn, Ga, Ge and As. •The calculations are performed using the configuration interaction method (CIV3). •We have calculated the oscillator strengths, line strengths and transition rates. •The wavelengths of the transitions are listed in this article. •We also have made comparisons between our data and other calculations.

Abou El-Maaref, A., E-mail: aahmh@hotmail.com [Physics Department, Faculty of Science, Al-Azhar University, Assuit (Egypt); Allam, S.H.; El-Sherbini, Th.M. [Laboratory of Lasers and New Materials, Physics Department, Faculty of Science, Cairo University, Giza (Egypt)] [Laboratory of Lasers and New Materials, Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

2014-01-15T23:59:59.000Z

205

Persistence of gamma-H2AX and 53BP1 foci in proliferating and nonproliferating human mammary epithelial cells after exposure to gamma-rays or iron ions  

SciTech Connect (OSTI)

To investigate {gamma}-H2AX (phosphorylated histone H2AX) and 53BP1 (tumour protein 53 binding protein No. 1) foci formation and removal in proliferating and non-proliferating human mammary epithelial cells (HMEC) after exposure to sparsely and densely ionizing radiation under different cell culture conditions. HMEC cells were grown either as monolayers (2D) or in extracellular matrix to allow the formation of acinar structures in vitro (3D). Foci numbers were quantified by image analysis at various time points after exposure. Our results reveal that in non-proliferating cells under 2D and 3D cell culture conditions, iron-ion induced {gamma}-H2AX foci were still present at 72 h after exposure, although 53BP1 foci returned to control levels at 48 h. In contrast in proliferating HMEC, both {gamma}-H2AX and 53BP1 foci decreased to control levels during the 24-48 h time interval after irradiation under 2D conditions. Foci numbers decreased faster after {gamma}-ray irradiation and returned to control levels by 12 h regardless of marker, cell proliferation status, and cell culture condition. Conclusions: The disappearance of radiation induced {gamma}-H2AX and 53BP1 foci in HMEC have different dynamics that depend on radiation quality and proliferation status. Notably, the general patterns do not depend on the cell culture condition (2D versus 3D). We speculate that the persistent {gamma}-H2AX foci in iron-ion irradiated non-proliferating cells could be due to limited availability of double strand break (DSB) repair pathways in G0/G1-phase, or that repair of complex DSB requires replication or chromatin remodeling.

Groesser, Torsten; Chang, Hang; Fontenay, Gerald; Chen, James; Costes, Sylvain V.; Barcellos-Hoff, Mary Helen; Parvin, Bahram; Rydberg, Bjorn

2010-12-22T23:59:59.000Z

206

Astrophysical S-factor for the radiative-capture reaction p{sup 13}C {yields} {sup 14}N{gamma}  

SciTech Connect (OSTI)

The possibility of describing experimental data on the astrophysical S factor for radiative proton capture on a {sup 13}C nucleus at energies in the range 0.03-0.8 MeV is considered within the potential cluster model involving forbidden states. It is shown that the energy dependence of this astrophysical S factor can be reasonably explained on the basis of the E1 transition to the {sup 3}P{sub 1}-wave bound state of the {sup 14}N nucleus in the p{sup 13}C channel from the {sup 3}S{sub 1} wave of p{sup 13}C scattering in the resonance energy region around 0.55 MeV in the laboratory frame.

Dubovichenko, S. B., E-mail: sergey@dubovichenko.ru [V.G. Fessenkov Astrophysical Institute (Kazakhstan)

2012-02-15T23:59:59.000Z

207

Radiation shielding composition  

DOE Patents [OSTI]

A composition for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm.sup.3 and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile.

Quapp, William J. (Idaho Falls, ID); Lessing, Paul A. (Idaho Falls, ID)

2000-12-26T23:59:59.000Z

208

Radiation shielding composition  

DOE Patents [OSTI]

A composition for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm.sup.3 and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile.

Quapp, William J. (Idaho Falls, ID); Lessing, Paul A. (Idaho Falls, ID)

1998-01-01T23:59:59.000Z

209

Radiation shielding composition  

DOE Patents [OSTI]

A composition is disclosed for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm{sup 3} and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile. 5 figs.

Quapp, W.J.; Lessing, P.A.

1998-07-28T23:59:59.000Z

210

Radiation Exposure in Biliary Procedures Performed to Manage Anastomotic Strictures in Pediatric Liver Transplant Recipients: Comparison Between Radiation Exposure Levels Using an Image Intensifier and a Flat-Panel Detector-Based System  

SciTech Connect (OSTI)

Purpose: The aim of this study was to estimate radiation exposure in pediatric liver transplants recipients who underwent biliary interventional procedures and to compare radiation exposure levels between biliary interventional procedures performed using an image intensifier-based angiographic system (IIDS) and a flat panel detector-based interventional system (FPDS). Materials and Methods: We enrolled 34 consecutive pediatric liver transplant recipients with biliary strictures between January 2008 and March 2013 with a total of 170 image-guided procedures. The dose-area product (DAP) and fluoroscopy time was recorded for each procedure. The mean age was 61 months (range 4-192), and mean weight was 17 kg (range 4-41). The procedures were classified into three categories: percutaneous transhepatic cholangiography and biliary catheter placement (n = 40); cholangiography and balloon dilatation (n = 55); and cholangiography and biliary catheter change or removal (n = 75). Ninety-two procedures were performed using an IIDS. Seventy-eight procedures performed after July 2010 were performed using an FPDS. The difference in DAP between the two angiographic systems was compared using Wilcoxon rank-sum test and a multiple linear regression model. Results: Mean DAP in the three categories was significantly greater in the group of procedures performed using the IIDS compared with those performed using the FPDS. Statistical analysis showed a p value = 0.001 for the PTBD group, p = 0.0002 for the cholangiogram and balloon dilatation group, and p = 0.00001 for the group with cholangiogram and biliary catheter change or removal. Conclusion: In our selected cohort of patients, the use of an FPDS decreases radiation exposure.

Miraglia, Roberto, E-mail: rmiraglia@ismett.edu; Maruzzelli, Luigi [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Department of Diagnostic and Interventional Radiology (Italy)] [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Department of Diagnostic and Interventional Radiology (Italy); Tuzzolino, Fabio [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Department of Information Technology (Italy)] [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Department of Information Technology (Italy); Indovina, Pietro Luigi [Medical Physic ISMETT Consultant, Fismeco (Italy)] [Medical Physic ISMETT Consultant, Fismeco (Italy); Luca, Angelo [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Department of Diagnostic and Interventional Radiology (Italy)] [Mediterranean Institute for Transplantation and Advanced Specialized Therapies (ISMETT), Department of Diagnostic and Interventional Radiology (Italy)

2013-12-15T23:59:59.000Z

211

GammaCam Technology Demonstration at ORNL Buildings 3026C and 3026D  

Broader source: Energy.gov [DOE]

The GammaCam system is an effective tool for remotely identifying high gamma radiation in radioactive environments.  Its versatility allows the user to perform preliminary characterization of an...

212

Alpha Radiation  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout theOFFICE OF RESEARCHThermal SolarAllocatioBasics of Radiation Gamma

213

Composition for radiation shielding  

DOE Patents [OSTI]

A composition for use as a radiation shield is disclosed. The shield has a depleted uranium core for absorbing gamma rays and a bismuth coating for preventing chemical corrosion and absorbing gamma rays. Alternatively, a sheet of gadolinium may be positioned between the uranium core and the bismuth coating for absorbing neutrons. The composition is preferably in the form of a container for storing materials that emit radiation such as gamma rays and neutrons. The container is preferably formed by casting bismuth around a pre-formed uranium container having a gadolinium sheeting, and allowing the bismuth to cool. The resulting container is a structurally sound, corrosion-resistant, radiation-absorbing container. 2 figs.

Kronberg, J.W.

1994-08-02T23:59:59.000Z

214

Energy levels, oscillator strengths, radiative decay rates, and fine-structure collision strengths for the Zn-like ions Nb XII and Mo XIII  

SciTech Connect (OSTI)

Energy levels, line strengths, oscillator strengths, radiative decay rates, and fine-structure collision strengths are presented for the Zn-like ions Nb XII and Mo XIII. The atomic data are calculated with the AUTOSTRUCTURE code, where relativistic corrections are introduced according to the Breit–Pauli distorted wave approach. We present the calculations of atomic data for 110 fine-structure levels generated from fifteen configurations (1s{sup 2}2s{sup 2}2p{sup 6}3s{sup 2}3p{sup 6}3d{sup 10})4s{sup 2}, 4s4p, 4p{sup 2}, 4s4d, 4s4f, 4s5s, 4p4d, 4s5p, 4s5d, 4p4f, 4p5s, 4d{sup 2}, 4d4f, 4f{sup 2}, and 3d{sup 9}4s{sup 2}4p. Fine-structure collision strengths for transitions from the ground and the first four excited levels are presented at six electron energies (20, 50, 80, 110, 150, and 180 Ryd). Our atomic structure data are compared with the available experimental and theoretical results.

Liang, Liang, E-mail: liangll501@163.com; Liu, Xu-yang; Zhou, Chao

2014-07-15T23:59:59.000Z

215

Proposal for a Nuclear Gamma-Ray Laser of Optical Range  

E-Print Network [OSTI]

A possibility of amplification of the 7.6 eV $\\gamma$-radiation by the stimulated $\\gamma$-emission of the ensemble of the $^{229m}$Th isomeric nuclei in a host dielectric crystal is proved theoretically. This amplification is a result of: 1) the excitation of a large number of the $^{229m}$Th isomers by laser radiation; 2) the creation of the inverse population of nuclear levels in a cooled sample owing to the interaction of thorium nuclei with the crystal electric field or with an external magnetic field; 3) the emissions/absorption of the optical photons by thorium nuclei in the crystal without recoil; 4) the nuclear spin relaxation through the conduction electrons of the metallic covering.

E. V. Tkalya

2011-04-23T23:59:59.000Z

216

Proposal for a Nuclear Gamma-Ray Laser of Optical Range  

SciTech Connect (OSTI)

A possibility of the amplification of the 7.6 eV {gamma} radiation by the stimulated {gamma} emission of the ensemble of the {sup 229m}Th isomeric nuclei in a host dielectric crystal is proved theoretically. This amplification is a result of (1) the excitation of a large number of {sup 229m}Th isomers by laser radiation, (2) the creation of the inverse population of nuclear levels in a cooled sample owing to the interaction of thorium nuclei with the crystal electric field or with an external magnetic field, (3) the emission or absorption of the optical photons by thorium nuclei in the crystal without recoil, and (4) the nuclear spin relaxation through the conduction electrons of the metallic covering.

Tkalya, E. V. [Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation)

2011-04-22T23:59:59.000Z

217

Gamma-ray observations of the Crab Region using a coded-aperture telescope  

SciTech Connect (OSTI)

The region of the Galactic anticenter, including the Crab Nebula, was observed during a balloon flight of the University of New Hampshire Directional Gamma-Ray Telescope employing the coded-aperture imaging technique to image celestial gamma-radiation between 160 keV and 9.3 MeV. The background systematics are treated with a simple and relatively straightforward correction procedure. The results demonstrate that the coded-aperture procedure is a viable approach for imaging not only point sources of radiation, but also extended sources of emission. The results for the Crab's photon spectrum are consistent with a power-law spectrum. Upper limits on the flux levels of line emission at 405 keV and 1050 keV and on the flux from the X-ray binary source A0535 + 26 and diffuse Galactic emission from the anticenter region are derived. 35 references.

Mcconnell, M.L.; Dunphy, P.P.; Forrest, D.J.; Chupp, E.L.; Owens, A.

1987-10-01T23:59:59.000Z

218

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

E-Print Network [OSTI]

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

Tomonori Totani

1999-04-13T23:59:59.000Z

219

Gamma Ray Burst and Soft Gamma Repeaters. Spinning, Precessing Gamma Jets  

E-Print Network [OSTI]

Gamma Ray Bursts as recent GRB990123 and GRB990510 are observed to occur in cosmic volumes with a corresponding output reaching, for isotropic explosions, energies as large as two solar masses annihilation. These energies are underestimated because of the neglected role of comparable ejected neutrinos bursts. These extreme power cannot be explained with any standard spherically symmetric Fireball model. A too heavy black hole or Star would be unable to coexist with the shortest millisecond time structure of Gamma ray Burst. Beaming of the gamma radiation may overcome the energy puzzle. However any mild explosive beam $(\\Omega > 10^{-2})$ should not solve the jet containment at those disruptive energies. Only extreme beaming $(\\Omega < 10^{-8})$, by a slow decaying, but long-lived precessing jet, it may coexist with characteristic Supernova energies, apparent GRBs output, statistics as well as their connection with older and nearer SGRs relics.

Daniele Fargion

1999-06-28T23:59:59.000Z

220

Determination of the properties of nuclear energy levels of La¹³? and Pr¹?¹ by the resonance fluorescence of neutron capture gamma rays  

E-Print Network [OSTI]

. It is interesting to note that 100 Kw. power level of the reactor used furnished a neutron flux of approximately 5 X 10 nv . at the polyvinyl 11 chloride source in the tangential beam tube. Accum- ulation times were as low as 100 min. for the Nal(T1) detector... Geometry of Self' Absorption Experiment 34 Geometry of Low Temperature Experiment 35 Expected Pesults of Absolute Scattering, Self Absorption, and Low Temperature Experimer ts 36 Experiment, al Arrangement of Detector, Scatterer, and Source 37...

Wilson, William Bradley

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Radiation Impact of Very Low Level Radioactive Steel Reused in Building Industry with Emphasis on External Exposure Pathway - 12569  

SciTech Connect (OSTI)

Considerable quantities of various materials are accumulated during the decommissioning process of nuclear installations. Some of arising materials are activated or contaminated. However, many of them continue to have an economic value and exist in a form that can be recycled or reused for special purposes. Furthermore much of the material generated during decommissioning process will contain only small amounts of radionuclides. For these materials there exist environmental and economic incentives to maximize the use of the concept of clearance from further regulatory control. This impact analysis is devoted to mentioned incentives. The aim is to conditionally clear maximum amount of the scrap steel and consequently recycle and reuse it in form of reinforcing components in tunnel and bridge building scenarios. Recent calculations relevant for external exposure pathway indicate that concept of conditional clearance represent a feasible option for the management of radioactive materials. Even in chosen specific industrial applications it is possible to justify new, approximately one order of magnitude higher, clearance levels. However analysis of other possible exposure pathways relevant for particular scenario of reuse of conditionally cleared materials has to be performed in order to confirm indications from partially obtained results. Basically, the concept of conditional clearance can bring two basic benefits. Firstly it is saving of considerable funds, which would be otherwise used for treatment, conditioning and disposal of materials at appropriate radioactive waste repository. Moreover materials with intrinsic value (particularly metals) can be recycled and reused in industrial applications instead of investing resources on mining and production process in order to obtain new, 'fresh' materials. (authors)

Panik, Michal; Hrncir, Tomas; Necas, Vladimir [Slovak University of Technology in Bratislava, Bratislava (Slovakia)

2012-07-01T23:59:59.000Z

222

The Northern Marshall Islands radiological survey: A quality control program for radiochemical and gamma spectroscopy analysis  

SciTech Connect (OSTI)

From 1979 to 1989, approximately 25,000 Post Northern Marshall Islands Radiological Survey (PNMIRS) samples were collected, and over 71,400 radiochemical and gamma spectroscopy analyses were performed to establish the concentration of {sup 90}Sr, {sup 137}Cs, {sup 241}Am, and plutonium isotopes in soil, vegetation, fish, and animals in the Northern Marshall Islands. While the Low Level Gamma Counting Facility (B379) in the Health and Ecological Assessment (HEA) division accounted for over 80% of all gamma spectroscopy analyses, approximately 4889 radiochemical and 5437 gamma spectroscopy analyses were performed on 4784 samples of soil, vegetation, terrestrial animal, and marine organisms by outside laboratories. Four laboratories were used by Lawrence Livermore National Laboratory (LLNL) to perform the radiochemical analyses: Thermo Analytical Norcal, Richmond, California (TMA); Nuclear Energy Services, North Carolina State University (NCSU); Laboratory of Radiation Ecology, University of Washington (LRE); and Health and Ecological Assessment (HEA) division, LLNL, Livermore, California. Additionally, LRE and NCSU were used to perform gamma spectroscopy analyses. The analytical precision and accuracy were monitored by including blind duplicates and natural matrix standards in each group of samples analyzed. On the basis of reported analytical values for duplicates and standards, 88% of the gamma and 87% of the radiochemical analyses in this survey were accepted. By laboratory, 93% of the radiochemical analyses by TMA; 88% of the gamma-ray spectrometry and 100% of the radiochemistry analyses by NCSU; 89% of the gamma spectroscopy and 87% of the radiochemistry analyses by LRE; and 90% of the radiochemistry analyses performed by HEA`s radiochemistry department were accepted.

Kehl, S.R.; Mount, M.E.; Robison, W.L.

1995-09-01T23:59:59.000Z

223

Gamma Ray Bursts  

E-Print Network [OSTI]

Olson. “Observations of gamma-ray bursts of cosmic origin. ”E. Lingenfelter. “Gamma-ray bursts. ” Annual Review of652-654. Waxman, Eli. “Gamma-ray-burst afterglow: supporting

Stahl, Bennett

2014-01-01T23:59:59.000Z

224

Search for $\\alpha$ decay of $^{151}$Eu to the first excited level of $^{147}$Pm using underground $\\gamma$-ray spectrometry  

E-Print Network [OSTI]

The alpha decay of $^{151}$Eu to the first excited level of $^{147}$Pm ($J^\\pi = 5/2^+$, $E_{exc}=91.1$ keV) was searched for at the HADES underground laboratory ($\\approx 500$ m w.e.). A sample of high purity europium oxide with mass of 303 g and a natural isotopic composition has been measured over 2232.8 h with a high energy resolution ultra-low background n-type semi-planar HPGe detector (40 cm$^3$) with sub-micron deadlayer. The new improved half-life limit has been set as $T_{1/2} \\geq 3.7\\times 10^{18}$ yr at 68% C.L. Possibilities to improve the sensitivity of the experiment, which is already near the theoretical predictions, are discussed. New half-life limit for $\\alpha$ decay of $^{153}$Eu is also set as $T_{1/2} \\geq 5.5\\times 10^{17}$ yr.

Danevich, F A; Hult, M; Marissens, G; Tretyak, V I; Yuksel, A; 10.1140/epja/i2012-12157-7

2013-01-01T23:59:59.000Z

225

A Model-Independent Search for the decay B->l nu gamma  

SciTech Connect (OSTI)

The authors present a search for the radiative leptonic decay B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}, where {ell} = e, {mu}, using a data sample of 465 million B{bar B} pairs collected by the BABAR experiment. In this analysis, they fully reconstruct the hadronic decay of one of the B mesons in {Upsilon}(4S) {yields} B{sup +}B{sup -} decays, then search for evidence of B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma} in the rest of the event. They observe no significant evidence of signal decays and report model-independent branching fraction upper limits of {Beta}(B{sup +} {yields} e{sup +}{nu}{sub e}{gamma}) < 17 x 10{sup -6}, {Beta}(B{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{gamma}) < 24 x 10{sup -6}, and {Beta}(B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}}{gamma}) < 15.6 x 10{sup -6} ({ell} = e or {mu}), all at the 90% confidence level.

Aubert, Bernard; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, David Nathan; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS; /more authors..

2012-10-09T23:59:59.000Z

226

Time encoded radiation imaging  

DOE Patents [OSTI]

The various technologies presented herein relate to detecting nuclear material at a large stand-off distance. An imaging system is presented which can detect nuclear material by utilizing time encoded imaging relating to maximum and minimum radiation particle counts rates. The imaging system is integrated with a data acquisition system that can utilize variations in photon pulse shape to discriminate between neutron and gamma-ray interactions. Modulation in the detected neutron count rates as a function of the angular orientation of the detector due to attenuation of neighboring detectors is utilized to reconstruct the neutron source distribution over 360 degrees around the imaging system. Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon scintillation material in the imager, the photons generated by the scintillation material are converted to electrical energy from which the respective neutrons/gamma rays can be determined and, accordingly, a direction to, and the location of, a radiation source identified.

Marleau, Peter; Brubaker, Erik; Kiff, Scott

2014-10-21T23:59:59.000Z

227

apm background radiation: Topics by E-print Network  

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

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

228

About radiative kaon decay \\k+ \\to ?+\\pi0?  

E-Print Network [OSTI]

With usage of the Low theorem the general expression for amplitude of radiative kaon decay \\k+ \\to \\pi+\\pi0\\gamma is determined.

V. P. Efrosinin

2006-06-20T23:59:59.000Z

229

accelerated radiative transfer: Topics by E-print Network  

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

Dominated Outflows Astrophysics (arXiv) Summary: Plasma outflows from gamma-ray bursts (GRB), pulsar winds, relativistic jets, and ultra-intense laser targets radiate...

230

Process for gamma ray induced degradation of polychlorinated biphenyls  

DOE Patents [OSTI]

The invention is a process for the in-situ destruction of polychlorinated biphenyl (PCB) compounds in transformer oils and transformers. These compounds are broken down selectively by irradiation of the object or mixture using spent nuclear fuel or any isotopic source of high energy gamma radiation. For example, the level of applied dose required to decompose 400 ppm of polychlorinated biphenyl in transformer oil to less than 50 ppm is 500 kilograms. Destruction of polychlorinated biphenyls to levels of less than 50 ppm renders the transformer oil or transformer non-PCB contaminated under current regulations. Therefore, this process can be used to treat PCB contaminated oil and equipment to minimize or eliminate the generation of PCB hazardous waste. 5 figs.

Meikrantz, D.H.; Mincher, B.J.; Arbon, R.E.

1998-08-25T23:59:59.000Z

231

Process for gamma ray induced degradation of polychlorinated biphenyls  

DOE Patents [OSTI]

The invention is a process for the in-situ destruction of polychlorinated biphenyl (PCB) compounds in transformer oils and transformers. These compounds are broken down selectively by irradiation of the object or mixture using spent nuclear fuel or any isotopic source of high energy gamma radiation. For example, the level of applied dose required to decompose 400 ppm of polychlorinated biphenyl in transformer oil to less than 50 ppm is 500 kilogray. Destruction of polychlorinated biphenyls to levels of less than 50 ppm renders the transformer oil or transformer non-PCB contaminated under current regulations. Therefore, this process can be used to treat PCB contaminated oil and equipment to minimize or eliminate the generation of PCB hazardous waste.

Meikrantz, David H. (Idaho Falls, ID); Mincher, Bruce J. (Shelley, ID); Arbon, Rodney E. (Blackfoot, ID)

1998-01-01T23:59:59.000Z

232

Current Trends in Gamma Ray Detection for Radiological Emergency Response  

SciTech Connect (OSTI)

Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies.

Mukhopadhyay, S., Guss, P., Maurer, R.

2011-08-18T23:59:59.000Z

233

Actively driven thermal radiation shield  

DOE Patents [OSTI]

A thermal radiation shield for cooled portable gamma-ray spectrometers. The thermal radiation shield is located intermediate the vacuum enclosure and detector enclosure, is actively driven, and is useful in reducing the heat load to mechanical cooler and additionally extends the lifetime of the mechanical cooler. The thermal shield is electrically-powered and is particularly useful for portable solid-state gamma-ray detectors or spectrometers that dramatically reduces the cooling power requirements. For example, the operating shield at 260K (40K below room temperature) will decrease the thermal radiation load to the detector by 50%, which makes possible portable battery operation for a mechanically cooled Ge spectrometer.

Madden, Norman W. (Livermore, CA); Cork, Christopher P. (Pleasant Hill, CA); Becker, John A. (Alameda, CA); Knapp, David A. (Livermore, CA)

2002-01-01T23:59:59.000Z

234

Gamma ray generator  

DOE Patents [OSTI]

An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

Firestone, Richard B; Reijonen, Jani

2014-05-27T23:59:59.000Z

235

Radiation Detection Computational Benchmark Scenarios  

SciTech Connect (OSTI)

Modeling forms an important component of radiation detection development, allowing for testing of new detector designs, evaluation of existing equipment against a wide variety of potential threat sources, and assessing operation performance of radiation detection systems. This can, however, result in large and complex scenarios which are time consuming to model. A variety of approaches to radiation transport modeling exist with complementary strengths and weaknesses for different problems. This variety of approaches, and the development of promising new tools (such as ORNL’s ADVANTG) which combine benefits of multiple approaches, illustrates the need for a means of evaluating or comparing different techniques for radiation detection problems. This report presents a set of 9 benchmark problems for comparing different types of radiation transport calculations, identifying appropriate tools for classes of problems, and testing and guiding the development of new methods. The benchmarks were drawn primarily from existing or previous calculations with a preference for scenarios which include experimental data, or otherwise have results with a high level of confidence, are non-sensitive, and represent problem sets of interest to NA-22. From a technical perspective, the benchmarks were chosen to span a range of difficulty and to include gamma transport, neutron transport, or both and represent different important physical processes and a range of sensitivity to angular or energy fidelity. Following benchmark identification, existing information about geometry, measurements, and previous calculations were assembled. Monte Carlo results (MCNP decks) were reviewed or created and re-run in order to attain accurate computational times and to verify agreement with experimental data, when present. Benchmark information was then conveyed to ORNL in order to guide testing and development of hybrid calculations. The results of those ADVANTG calculations were then sent to PNNL for compilation. This is a report describing the details of the selected Benchmarks and results from various transport codes.

Shaver, Mark W.; Casella, Andrew M.; Wittman, Richard S.; McDonald, Ben S.

2013-09-24T23:59:59.000Z

236

Afterglows as Diagnostics of Gamma Ray Burst Beaming  

E-Print Network [OSTI]

If gamma ray bursts are highly collimated, radiating into only a small fraction of the sky, the energy requirements of each event may be reduced by several (up to 4 - 6) orders of magnitude, and the event rate increased correspondingly. The large Lorentz factors (Gamma > 100) inferred from GRB spectra imply relativistic beaming of the gamma rays into an angle 1/Gamma. We are at present ignorant of whether there are ejecta outside this narrow cone. Afterglows allow empirical tests of whether GRBs are well-collimated jets or spherical fireballs. The bulk Lorentz factor decreases and radiation is beamed into an ever increasing solid angle as the burst remnant expands. It follows that if gamma ray bursts are highly collimated, many more optical and radio transients should be observed without associated gamma rays than with them. In addition, a burst whose ejecta are beamed into angle zeta undergoes a qualitative change in evolution when Gamma < 1/zeta: Before this, Gamma ~ r^{-3/2}, while afterwards, Gamma decays exponentially with r. This change results in a potentially observable break in the afterglow light curve. Successful application of either test would eliminate the largest remaining uncertainty in the energy requirements and space density of gamma ray bursters.

James E. Rhoads

1997-12-03T23:59:59.000Z

237

UTILIZATION OF PHOSWICH DETECTORS FOR SIMULTANEOUS, MULTIPLE RADIATION DETECTION  

SciTech Connect (OSTI)

A phoswich radiation detector is comprised of a phosphor sandwich in which several different phosphors are viewed by a common photomultiplier. By selecting the appropriate phosphors, this system can be used to simultaneously measure multiple radiation types (alpha, beta, gamma and/or neutron) with a single detector. Differentiation between the signals from the different phosphors is accomplished using digital pulse shape discrimination techniques. This method has been shown to result in accurate discrimination with highly reliable and versatile digital systems. This system also requires minimal component count (i.e. only the detector and a computer for signal processing). A variety of detectors of this type have been built and tested including: (1) a triple phoswich system for alpha/beta/gamma swipe counting, (2) two well-type detectors for measuring low levels of low energy photons in the presence of a high energy background, (3) a large area detector for measuring beta contamination in the presence of a photon background, (4) another large area detector for measuring low energy photons from radioactive elements such as uranium in the presence of a photon background. An annular geometry, triple phoswich system optimized for measuring alpha/beta/gamma radiation in liquid waste processing streams is currently being designed.

William H. Miller; Manuel Diaz de Leon

2003-04-15T23:59:59.000Z

238

Gamma Ray Imaging for Environmental Remediation  

SciTech Connect (OSTI)

This program is the development of germanium strip detectors for environmental remediation. It is a collaboration between the Naval Research Laboratory and Lawrence Berkeley National Lab. The goal is to develop detectors that are simultaneously capable of excellent spectroscopy and imaging of gamma radiation.

B.F. Philips; R.A. Kroeger: J.D. Kurfess: W.N. Johnson; E.A. Wulf; E. I. Novikova

2004-11-12T23:59:59.000Z

239

Atomic Radiation (Illinois)  

Broader source: Energy.gov [DOE]

This article states permissible levels of radiation in unrestricted areas, environmental standards for uranium fuel cycle and information about notification of incidents.

240

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

E-Print Network [OSTI]

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

Pijushpani Bhattacharjee; Nayantara Gupta

2003-05-12T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Did a gamma-ray burst initiate the late Ordovician mass extinction?  

E-Print Network [OSTI]

Did a gamma-ray burst initiate the late Ordovician mass extinction? A.L. Melott1 , B.S. Lieberman2 Abstract: Gamma-ray bursts (GRBs) produce a flux of radiation detectable across the observable Universe words: Population and evolution, mass extinction, gamma-ray burst, Ordovician, ultraviolet ozone

Jackman, Charles H.

242

Fiber fed x-ray/gamma ray imaging apparatus  

DOE Patents [OSTI]

X-ray/gamma ray imaging apparatus is disclosed for detecting the position, energy, and intensity of x-ray/gamma ray radiation comprising scintillation means disposed in the path of such radiation and capable of generating photons in response to such radiation; first photodetection means optically bonded to the scintillation means and capable of generating an electrical signal indicative of the intensity, and energy of the radiation detected by the scintillation means; second photodetection means capable of generating an electrical signal indicative of the position of the radiation in the radiation pattern; and means for optically coupling the scintillation means to the second photodetection means. The photodetection means are electrically connected to control and storage means which may also be used to screen out noise by rejecting a signal from one photodetection means not synchronized to a signal from the other photodetection means; and also to screen out signals from scattered radiation. 6 figs.

Hailey, C.J.; Ziock, K.P.

1992-06-02T23:59:59.000Z

243

Fiber fed x-ray/gamma ray imaging apparatus  

DOE Patents [OSTI]

X-ray/gamma ray imaging apparatus is disclosed for detecting the position, energy, and intensity of x-ray/gamma ray radiation comprising scintillation means disposed in the path of such radiation and capable of generating photons in response to such radiation; first photodetection means optically bonded to the scintillation means and capable of generating an electrical signal indicative of the intensity, and energy of the radiation detected by the scintillation means; second photodetection means capable of generating an electrical signal indicative of the position of the radiation in the radiation pattern; and means for optically coupling the scintillation means to the second photodetection means. The photodetection means are electrically connected to control and storage means which may also be used to screen out noise by rejecting a signal from one photodetection means not synchronized to a signal from the other photodetection means; and also to screen out signals from scattered radiation.

Hailey, Charles J. (San Francisco, CA); Ziock, Klaus-Peter (Livermore, CA)

1992-01-01T23:59:59.000Z

244

Remote Gamma Scanning System for Characterization of BWR and PWR Fuel Rod Sections  

SciTech Connect (OSTI)

Sometimes challenges with the design and deployment of automated equipment in remote environments deals more with the constraints imposed by the remote environment than it does with the details of the automation. This paper discusses the development of a scanning system used to provide gamma radiation profiles of irradiated fuel rod segments. The system needed the capability to provide axial scans of cut segments of BWR and PWR fuel rods. The scanning location is A-Cell at the Radiochemical Processing Laboratory (RPL) at the Hanford site in Washington State. The criteria for the scanning equipment included axial scanning increments of a tenth of an inch or less, ability to scan fuel rods with diameters ranging from 3/8 inch to 5/8 inch in diameter, and fuel rod segments up to seven feet in length. Constraints imposed by the environment included having the gamma detector and operator controls on the outside of the hot cell and the scanning hardware on the inside of the hot cell. This entailed getting a narrow, collimated beam of radiation from the fuel rod to the detector on the outside of the hot cell while minimizing the radiation exposure caused by openings for the wires and cables traversing the hot cell walls. Setup and operation of all of the in-cell hardware needed to accommodate limited access ports and use of hot cell manipulators. The radiation levels inside the cell also imposed constraints on the materials used.

Crowell, Shannon L.; Alzheimer, James M.

2011-08-08T23:59:59.000Z

245

Angular and Energy Characteristics of Gamma Field at the New Safe Confinement Construction Sit  

SciTech Connect (OSTI)

To results of measurements of angular y and energy distribution of gamma-radiation at the cites of New Safe Confinement erection. The data analysis permitted to identify the main sources of gamma-radiation and to systematize the obtained results.

Batiy, Valeriy; Glebkin, S; Pavlovskiy, L; Pravdyvyi, O; Rudko, Vladimir; Shcherbin, Vladimir; Stojanov, O; Schmieman, Eric A.

2005-08-08T23:59:59.000Z

246

A Search for the Rare Decay $B\\rightarrow\\gamma\\gamma$  

SciTech Connect (OSTI)

We report the result of a search for the rare decay B{sup 0} {yields} {gamma}{gamma} in 426 fb{sup -1} of data, corresponding to 226 million B{sup 0}{bar B}{sup 0} pairs, collected on the {Upsilon}(4S) resonance at the PEP-II asymmetric-energy e{sup +}e{sup -} collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21{sub -12}{sup +13} signal events with a statistical signficance of 1.9 {sigma}. This corresponds to a branching fraction {Beta}(B{sup 0} {yields} {gamma}{gamma}) = (1.7 {+-} 1.1(stat.) {+-} 0.2(syst.)) x 10{sup -7}. Based on this result, we set a 90% confidence level upper limit of {Beta}(B{sup 0} {yields} {gamma}{gamma}) < 3.2 x 10{sup -7}.

del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

2011-06-02T23:59:59.000Z

247

Gamma ray detector shield  

DOE Patents [OSTI]

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

Ohlinger, R.D.; Humphrey, H.W.

1985-08-26T23:59:59.000Z

248

Search for charmonium and charmoniumlike states in {Upsilon}(2S) radiative decays  

SciTech Connect (OSTI)

Using a sample of 158x10{sup 6} {Upsilon}(2S) events collected with the Belle detector, charmonium and charmoniumlike states with even charge parity are searched for in {Upsilon}(2S) radiative decays. No significant {chi}{sub cJ} or {eta}{sub c} signal is observed, and the following upper limits at 90% confidence level (C. L.) are obtained: B({Upsilon}(2S){yields}{gamma}{chi}{sub c0})<1.0x10{sup -4}, B({Upsilon}(2S){yields}{gamma}{chi}{sub c1})<3.6x10{sup -6}, B({Upsilon}(2S){yields}{gamma}{chi}{sub c2})<1.5x10{sup -5}, and B({Upsilon}(2S){yields}{gamma}{eta}{sub c})<2.7x10{sup -5}. No significant signal of any charmoniumlike state is observed, and we obtain the limits B({Upsilon}(2S){yields}{gamma}X(3872))xB(X(3872){yields}{pi}{sup +}{pi}{sup -}J/{psi})<0.8x10{sup -6}, B({Upsilon}(2S){yields}{gamma}X(3872))x B(X(3872){yields}{pi}{sup +}{pi}{sup -}{pi}{sup 0}J/{psi})<2.4x10{sup -6}, B({Upsilon}(2S){yields}{gamma}X(3915))xB(X(3915){yields}{omega}J/{psi})<2.8x10{sup -6}, B({Upsilon}(2S){yields}{gamma}Y(4140))xB(Y(4140){yields}{phi}J/{psi}))<1.2x10{sup -6}, and B({Upsilon}(2S){yields}{gamma}X(4350))xB(X(4350){yields}{phi}J/{psi}))<1.3x10{sup -6} at 90% C. L.

Wang, X. L.; Yuan, C. Z.; Wang, P. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Shen, C. P.; Hayasaka, K.; Iijima, T.; Miyazaki, Y.; Ohshima, T.; Senyo, K.; Seon, O. [Nagoya University, Nagoya (Japan); Adachi, I.; Haba, J.; Itoh, R.; Iwasaki, Y.; Katayama, N.; Kichimi, H.; Nakao, M.; Nishida, S.; Sakai, Y.; Trabelsi, K. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)

2011-10-01T23:59:59.000Z

249

An investigation of the use of semiconductors as detectors of nuclear radiation  

E-Print Network [OSTI]

Counter Both semiconductors and G-M tubes using this multiplication effect produce pulses which are independent of the type or energy of the incident radiation. Therefore, the pulses produced by this process can not be used to measure particle energy... of Energy Figure 9 Energy Level Across Junction A particle of energy due to some type of radiation such as photons, alpha, beta, and gamma rays penetrating in the vicinity of the junction can collide with an electron in the valence band with sufficient...

Ivy, Edward Weber

1960-01-01T23:59:59.000Z

250

Gamma-ray burst data from DMSP satellites  

SciTech Connect (OSTI)

A number of gamma-ray bursts have been detected by means of gamma-ray detectors aboard three Air Force Defense Meteorological Satellite Program (DMSP) satellites, in polar orbits at 800 km altitude. The gamma-ray data have a 2-second resolving time, and are usually telemetered in 5 energy bins in the range 50--1000 keV. Although it is not possible to detect gamma-ray bursts when the DMSP satellites are passing through the radiation belt or the South Atlantic Anomaly, or when the source is obscured by the Earth, a number of gamma-ray bursts have been detected by two or even three of the satellites. The DMSP data may be of considerable, assistance in evaluating time histories, locations, and spectra of gamma-ray bursts.

Terrell, J.; Klebesadel, R.W.; Lee, P. (Los Alamos National Lab., NM (United States)); Griffee, J.W. (Sandia National Labs., Albuquerque, NM (United States))

1991-01-01T23:59:59.000Z

251

Gamma-ray burst data from DMSP satellites  

SciTech Connect (OSTI)

A number of gamma-ray bursts have been detected by means of gamma-ray detectors aboard three Air Force Defense Meteorological Satellite Program (DMSP) satellites, in polar orbits at 800 km altitude. The gamma-ray data have a 2-second resolving time, and are usually telemetered in 5 energy bins in the range 50--1000 keV. Although it is not possible to detect gamma-ray bursts when the DMSP satellites are passing through the radiation belt or the South Atlantic Anomaly, or when the source is obscured by the Earth, a number of gamma-ray bursts have been detected by two or even three of the satellites. The DMSP data may be of considerable, assistance in evaluating time histories, locations, and spectra of gamma-ray bursts.

Terrell, J.; Klebesadel, R.W.; Lee, P. [Los Alamos National Lab., NM (United States); Griffee, J.W. [Sandia National Labs., Albuquerque, NM (United States)

1991-12-31T23:59:59.000Z

252

Gamma-ray burst interaction with dense interstellar medium  

E-Print Network [OSTI]

Interaction of cosmological gamma ray burst radiation with the dense interstellar medium of host galaxy is considered. Gas dynamical motion of interstellar medium driven by gamma ray burst is investigated in 2D approximation for different initial density distributions of host galaxy matter and different total energy of gamma ray burst. The maximum velocity of motion of interstellar medium is $1.8\\cdot10^4$ km/s. Light curves of gamma ray burst afterglow are calculated for set of non homogeneous density, distribution gamma ray burst total energy, and different viewing angles. Spectra of gamma ray burst afterglow are modeled taking into account conversion of hard photons (soft X-ray, hard UV) to soft UV and optics photons.

Maxim Barkov; Gennady Bisnovatyi-Kogan

2004-10-07T23:59:59.000Z

253

Energetics of Gamma Ray Bursts  

E-Print Network [OSTI]

We determine the distribution of total energy emitted by gamma-ray bursts for bursts with fluences and distance information. Our core sample consists of eight bursts with BATSE spectra and spectroscopic redshifts. We extend this sample by adding four bursts with BATSE spectra and host galaxy R magnitudes. From these R magnitudes we calculate a redshift probability distribution; this method requires a model of the host galaxy population. From a sample of ten bursts with both spectroscopic redshifts and host galaxy R magnitudes (some do not have BATSE spectra) we find that the burst rate is proportional to the galaxy luminosity at the epoch of the burst. Assuming that the total energy emitted has a log-normal distribution, we find that the average emitted energy (assumed to be radiated isotropically) is $gamma iso} > = 1.3^{+1.2}_{-1.0} \\times 10^{53}$ ergs (for H$_0$ = 65 km s$^{-1}$ Mpc$^{-1}$, $\\Omega_m=0.3$ and $\\Omega_\\Lambda=0.7$); the distribution has a logarithmic width of $\\sigma_\\gamma=1.7^{+0.7}_{-0.3}$. The corresponding distribution of X-ray afterglow energy (for seven bursts) has $ = 4.0^{+1.6}_{-1.8} \\times 10^{51}$ergs and $\\sigma_X = 1.3^{+0.4}_{-0.3}$. For completeness, we also provide spectral fits for all bursts with BATSE spectra for which there were afterglow searches.

Raul Jimenez; David Band; Tsvi Piran

2001-03-16T23:59:59.000Z

254

Gamma-Ray Bursts: Jets and Energetics  

E-Print Network [OSTI]

The relativistic outflows from gamma-ray bursts are now thought to be narrowly collimated into jets. After correcting for this jet geometry there is a remarkable constancy of both the energy radiated by the burst and the kinetic energy carried by the outflow. Gamma-ray bursts are still the most luminous explosions in the Universe, but they release energies that are comparable to supernovae. The diversity of cosmic explosions appears to be governed by the fraction of energy that is coupled to ultra-relativistic ejecta.

D. A. Frail

2003-11-12T23:59:59.000Z

255

Radiation effects on reactor pressure vessel supports  

SciTech Connect (OSTI)

The purpose of this report is to present the findings from the work done in accordance with the Task Action Plan developed to resolve the Nuclear Regulatory Commission (NRC) Generic Safety Issue No. 15, (GSI-15). GSI-15 was established to evaluate the potential for low-temperature, low-flux-level neutron irradiation to embrittle reactor pressure vessel (RPV) supports to the point of compromising plant safety. An evaluation of surveillance samples from the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) had suggested that some materials used for RPV supports in pressurized-water reactors could exhibit higher than expected embrittlement rates. However, further tests designed to evaluate the applicability of the HFIR data to reactor RPV supports under operating conditions led to the conclusion that RPV supports could be evaluated using traditional method. It was found that the unique HFIR radiation environment allowed the gamma radiation to contribute significantly to the embrittlement. The shielding provided by the thick steel RPV shell ensures that degradation of RPV supports from gamma irradiation is improbable or minimal. The findings reported herein were used, in part, as the basis for technical resolution of the issue.

Johnson, R.E. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering Technology; Lipinski, R.E. [Idaho National Engineering Lab., Rockville, MD (United States)

1996-05-01T23:59:59.000Z

256

Standards for Protection Against Radiation (Michigan)  

Broader source: Energy.gov [DOE]

This rule establishes standards for protection against radiation hazards. In addition to complying with requirements set forth, every reasonable effort should be made to maintain radiation levels...

257

Amorphous silicon radiation detectors  

DOE Patents [OSTI]

Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

Street, Robert A. (Palo Alto, CA); Perez-Mendez, Victor (Berkeley, CA); Kaplan, Selig N. (El Cerrito, CA)

1992-01-01T23:59:59.000Z

258

Amorphous silicon radiation detectors  

DOE Patents [OSTI]

Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification. 13 figs.

Street, R.A.; Perez-Mendez, V.; Kaplan, S.N.

1992-11-17T23:59:59.000Z

259

Effect of surface treatments on radiation buildup in steam generators  

SciTech Connect (OSTI)

Test coupons of typical PWR materials of construction were prepared using a number of pretreatments to minimize radiation buildup. The coupons were then exposed to primary coolant at the Doel-2 PWR in Belgium. The exposure periods for the coupons ranged from one to three fuel cycles. After removal from the primary system, doserate and gamma spectroscopy measurements were made to determine the radioactivity levels on the coupons. Varying levels of success were achieved for the preconditioning techniques tested. Electropolishing alone provided some degree of resistance to radiation buildup on the treated surface and electropolishing plus passivation was shown to be even better. Radiation buildup resistance of the palladium-coated coupons was poor; radiation levels on these coupons were even higher than on the untreated reference coupons. The poor performance of the palladium-coated coupons was possibly due to the method used to apply the coating. In contrast to palladium coating, very encouraging results were achieved with chromium plating plus passivation. Preliminary results show that this technique can inhibit activity deposition by as much as a factor of ten. 4 refs., 64 figs., 26 tabs.

Asay, R.H. (Radiological and Chemical Technology, Inc., Santa Clara, CA (United States)); Pick, M.E. (Nuclear Electric plc, Berkeley (United Kingdom). Berkeley Nuclear Labs.); Roofthooft, R. (Laboratoire Belge de l'Industrie Electrique (LABORELEC), Linkebeek (Belgium)); van Melsen, C. (Energy Invest, Beersel (Belgium))

1991-11-01T23:59:59.000Z

260

Environmental measurement-while-drilling-gamma ray spectrometer (EMWD-GRS) system technology demonstration plan for use at the Savannah River Site F-Area Retention Basin  

SciTech Connect (OSTI)

The Environmental Measurement-While-Drilling-Gamma Ray Spectrometer (EMWD-GRS) system represents an innovative blend of new and existing technology that provides the capability of producing real-time environmental and drillbit data during drilling operations. This demonstration plan presents information on the EMWD-GRS technology, demonstration design, Cs-137 contamination at the Savannah River Site F-Area Retention Basin, responsibilities of demonstration participants, and the policies and procedures for the demonstration to be conducted at the Savannah River Site F-Area Retention Basin. The EMWD-GRS technology demonstration will consist of continuously monitoring for gamma-radiation contamination while drilling two horizontal boreholes below the backfilled retention basin. These boreholes will pass near previously sampled vertical borehole locations where concentrations of contaminant levels are known. Contaminant levels continuously recorded by the EMWD-GRS system during drilling will be compared to contaminant levels previously determined through quantitative laboratory analysis of soil samples.

Williams, C.V.; Lockwood, G.J.; Normann, R.A. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); Gruebel, R.D. [Tech Reps, Inc., Albuquerque, NM (United States)] [Tech Reps, Inc., Albuquerque, NM (United States)

1996-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Gamma Ray Bursts Sudden, intense flashes of gamma rays  

E-Print Network [OSTI]

Gamma Ray Bursts #12;The Case Sudden, intense flashes of gamma rays come from nowhere and disappear with out a trace. Incredibly powerful: A single gamma ray burst is hundreds of times brighter a supernova #12;Who Vela (1960's) Looking for arms testing, found gamma ray bursts Compton Gamma Ray Observatory

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

262

Effects of p60 sCo gamma radiation on Sarcina lutea: A comparison of effects at two different exposure rates and a study of the radiosensitizing properties of prodigiosin.  

E-Print Network [OSTI]

of pigmented and nonpigmented cells. Radiation Res. 48, 40-52 (1971). 8. R. P. Williams, Biosynthesis of Prodigiosin, a Secondary Metabolite of Serratia marcescens, ~A 1. Microbiol. 25, 396-402 (1973). 9. M. M. Matthews, and N. I. Krinsky, The relatioship... Radiation on Sarcina ]utes: A Comparison of Effects at Two Different Exposure Rates and A Study of the Radiosensitizing Properties of. Prodigiosin (August 1973) George W. Blair, Jr. , B. S, , University of Chattanooga Directed by: Dr. R. D. Neff...

Blair, George Washington

1973-01-01T23:59:59.000Z

263

E-Print Network 3.0 - analog-digital radiation hard Sample Search...  

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

ASIC appears to have 100% yield (no bad... just want the result 12;Synchrotron Radiation: the Photon Superprobe Covers Infrared to Gamma... different instrumentation and...

264

E-Print Network 3.0 - annihilation radiation telescope Sample...  

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

Collection: Physics 3 MPI Kernphysik, Heidelberg Humboldt Univ. Berlin Summary: Gamma ray bursts Cosmology Diffuse extragalactic radiation fields via cutoff in AGN spectra and...

265

A Plasma Instability Theory of Gamma-Ray Burst Emission  

E-Print Network [OSTI]

A new theory for gamma-ray burst radiation is presented. In this theory, magnetic fields and relativistic electrons are created through plasma processes arising as a relativistic shell passes through the interstellar medium. The gamma-rays are produced through synchrotron self-Compton emission. It is found that shocks do not arise in this theory, and that efficient gamma-ray emission only occurs for a high Lorentz factor and a high-density interstellar medium. The former explains the absence of gamma-ray bursts with thermal spectra. The latter provides the Compton attenuation theory with an explanation of why the interstellar medium density is always high. The theory predicts the existence of a class of extragalactic optical transient that emit no gamma-rays.

J. J. Brainerd

1999-04-02T23:59:59.000Z

266

Gamma-ray Astronomy: Implications for Fundamental Physics  

E-Print Network [OSTI]

Gamma-ray Astronomy studies cosmic accelerators through their electromagnetic radiation in the energy range between ~100 MeV and ~100 TeV. The present most sensitive observations in this energy band are performed, from space, by the Large Area Telescope onboard the Fermi satellite and, from Earth, by the Imaging Air Cherenkov Telescopes MAGIC, H.E.S.S. and VERITAS. These instruments have revolutionized the field of Gamma-ray Astronomy, discovering different populations of gamma-ray emitters and studying in detail the non-thermal astrophysical processes producing this high-energy radiation. The scientific objectives of these observatories include also questions of fundamental physics. With gamma-ray instruments we study the origin of Galactic cosmic rays, testing the hypothesis or whether they are mainly produced in supernova explosions. Also, we obtain the most sensitive measurement of the cosmic electron-positron spectrum between 20 GeV and 5 TeV. By observing the gamma-ray emission from sources at cosmological distances, we learn about the intensity and evolution of the extragalactic background light, and perform tests of Lorentz Invariance. Moreover, we can search for dark matter by looking for gamma-ray signals produced by its annihilation or decay in over-density sites. In this paper, we review the most recent results produced with the current generation of gamma-ray instruments in these fields of research.

Javier Rico

2011-11-28T23:59:59.000Z

267

Radiation-resistant microorganism  

DOE Patents [OSTI]

An isolated and purified bacterium is provided which was isolated from a high-level radioactive waste site of mixed waste. The isolate has the ability to degrade a wide variety of organic contaminants while demonstrating high tolerance to ionizing radiation. The organism is uniquely suited to bioremediation of a variety or organic contaminants while in the presence of ionizing radiation.

Fliermans, Carl B.

2010-06-15T23:59:59.000Z

268

Optical gamma thermometer  

DOE Patents [OSTI]

An optical gamma thermometer includes a metal mass having a temperature proportional to a gamma flux within a core of a nuclear reactor, and an optical fiber cable for measuring the temperature of the heated metal mass. The temperature of the heated mass may be measured by using one or more fiber grating structures and/or by using scattering techniques, such as Raman, Brillouin, and the like. The optical gamma thermometer may be used in conjunction with a conventional reactor heat balance to calibrate the local power range monitors over their useful in-service life. The optical gamma thermometer occupies much less space within the in-core instrument tube and costs much less than the conventional gamma thermometer.

Koster, Glen Peter; Xia, Hua; Lee, Boon Kwee

2013-08-06T23:59:59.000Z

269

Offsite environmental monitoring report: Radiation monitoring around United States nuclear test areas, calendar year 1997  

SciTech Connect (OSTI)

This report describes the Offsite Radiological Environmental Monitoring Program (OREMP) conducted during 1997 by the US Environmental Protection Agency`s (EPAs), Radiation and Indoor Environments National Laboratory, Las Vegas, Nevada. This laboratory operated an environmental radiation monitoring program in the region surrounding the Nevada Test Site (NTS) and at former test sites in Alaska, Colorado, Mississippi, Nevada, and New Mexico. The surveillance program is designed to measure levels and trends of radioactivity, if present, in the environment surrounding testing areas to ascertain whether current radiation levels and associated doses to the general public are in compliance with existing radiation protection standards. The surveillance program additionally has the responsibility to take action to protect the health and well being of the public in the event of any accidental release of radioactive contaminants. Offsite levels of radiation and radioactivity are assessed by sampling and analyzing milk, water, and air; by deploying and reading thermoluminescent dosimeters (TLDs); and using pressurized ionization chambers (PICs) to measure ambient gamma exposure rates with a sensitivity capable of detecting low level exposures not detected by other monitoring methods.

Davis, M.G.; Flotard, R.D.; Fontana, C.A.; Hennessey, P.A.; Maunu, H.K.; Mouck, T.L.; Mullen, A.A.; Sells, M.D.

1999-01-01T23:59:59.000Z

270

Point-like gamma ray sources as signatures of distant accelerators of ultra high energy cosmic rays  

E-Print Network [OSTI]

We discuss the possibility of observing distant accelerators of ultra high energy cosmic rays in synchrotron gamma rays. Protons propagating away from their acceleration sites produce extremely energetic electrons during photo-pion interactions with cosmic microwave background photons. If the accelerator is embedded in a magnetized region, these electrons will emit high energy synchrotron radiation. The resulting synchrotron source is expected to be point-like and detectable in the GeV-TeV energy range if the magnetic field is at the nanoGauss level.

S. Gabici; F. A. Aharonian

2005-05-22T23:59:59.000Z

271

Radiation: Radiation Control (Indiana)  

Broader source: Energy.gov [DOE]

It is the policy of the state to encourage the constructive uses of radiation and to control its harmful effects. This section contains regulations pertaining to the manufacture, use,...

272

Radiation analysis devices, radiation analysis methods, and articles of manufacture  

DOE Patents [OSTI]

Radiation analysis devices include circuitry configured to determine respective radiation count data for a plurality of sections of an area of interest and combine the radiation count data of individual of sections to determine whether a selected radioactive material is present in the area of interest. An amount of the radiation count data for an individual section is insufficient to determine whether the selected radioactive material is present in the individual section. An article of manufacture includes media comprising programming configured to cause processing circuitry to perform processing comprising determining one or more correction factors based on a calibration of a radiation analysis device, measuring radiation received by the radiation analysis device using the one or more correction factors, and presenting information relating to an amount of radiation measured by the radiation analysis device having one of a plurality of specified radiation energy levels of a range of interest.

Roybal, Lyle Gene

2010-06-08T23:59:59.000Z

273

Neutron counting and gamma spectroscopy with PVT detectors.  

SciTech Connect (OSTI)

Radiation portals normally incorporate a dedicated neutron counter and a gamma-ray detector with at least some spectroscopic capability. This paper describes the design and presents characterization data for a detection system called PVT-NG, which uses large polyvinyl toluene (PVT) detectors to monitor both types of radiation. The detector material is surrounded by polyvinyl chloride (PVC), which emits high-energy gamma rays following neutron capture reactions. Assessments based on high-energy gamma rays are well suited for the detection of neutron sources, particularly in border security applications, because few isotopes in the normal stream of commerce have significant gamma ray yields above 3 MeV. Therefore, an increased count rate for high-energy gamma rays is a strong indicator for the presence of a neutron source. The sensitivity of the PVT-NG sensor to bare {sup 252}Cf is 1.9 counts per second per nanogram (cps/ng) and the sensitivity for {sup 252}Cf surrounded by 2.5 cm of polyethylene is 2.3 cps/ng. The PVT-NG sensor is a proof-of-principal sensor that was not fully optimized. The neutron detector sensitivity could be improved, for instance, by using additional moderator. The PVT-NG detectors and associated electronics are designed to provide improved resolution, gain stability, and performance at high-count rates relative to PVT detectors in typical radiation portals. As well as addressing the needs for neutron detection, these characteristics are also desirable for analysis of the gamma-ray spectra. Accurate isotope identification results were obtained despite the common impression that the absence of photopeaks makes data collected by PVT detectors unsuitable for spectroscopic analysis. The PVT detectors in the PVT-NG unit are used for both gamma-ray and neutron detection, so the sensitive volume exceeds the volume of the detection elements in portals that use dedicated components to detect each type of radiation.

Mitchell, Dean James; Brusseau, Charles A.

2011-06-01T23:59:59.000Z

274

Influence of Extraterrestrial Radiation on Radiation Portal Monitors  

SciTech Connect (OSTI)

Cosmic radiation and solar flares can be a major source of background radiation at the Earth’s surface. This paper examines the relationship between extraterrestrial radiation and the detectable background in radiation portal monitors used for homeland security applications. Background radiation data from 13 radiation portal monitor facilities are examined and compared against external sources of data related to extraterrestrial radiation, including measurements at neutron monitors located at 53 cosmic-ray observatories around the Earth, four polar orbiting satellites, three geostationary satellites, ground-based geomagnetic field data from observatories around the Earth, a solar magnetic index, solar radio flux data, and sunspot activity data. Four-years (January 2003 through December 2006) of data are used in this study, which include the latter part of Solar Cycle 23 as solar activity was on the decline. The analysis shows a significant relationship between some extraterrestrial radiation and the background detected in the radiation portal monitors. A demonstrable decline is shown in the average gamma ray and neutron background at the radiation portal monitors as solar activity declined over the period of the study.

Keller, Paul E.; Kouzes, Richard T.

2009-06-01T23:59:59.000Z

275

Gamma-ray Astronomy  

E-Print Network [OSTI]

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

Jim Hinton

2007-12-20T23:59:59.000Z

276

Did a gamma-ray burst initiate the late Ordovician mass extinction?  

E-Print Network [OSTI]

Gamma-ray bursts (GRBs) produce a flux of radiation detectable across the observable Universe. A GRB within our own galaxy could do considerable damage to the Earth's biosphere; rate estimates suggest that a dangerously near GRB should occur...

Melott, Adrian L.; Lieberman, Bruce S.; Laird, C. M.; Martin, Larry D.; Medvedev, Mikhail V.; Thomas, B. C.; Cannizzo, J. K.; Gehrels, N.; Jackman, C. H.

2004-01-01T23:59:59.000Z

277

RADIATION MONITORING  

E-Print Network [OSTI]

of Monitoring for Radiation Protection of Workers" in ICRPNo. 9, in "Advances in Radiation Protection and Dosimetry inDosimetry f o r Stray Radiation Monitoring on the CERN S i t

Thomas, R.H.

2010-01-01T23:59:59.000Z

278

Daily and Long Term Variations of Out-Door Gamma Dose Rate in Khorasan Province, Iran  

SciTech Connect (OSTI)

In Iran before 1996, only a few hot spots had been identified, no systematic study had been envisaged. Since then preparation of out-door environmental gamma radiation map of Iran was defined as a long term goal in our center, at the same time simultaneous monitoring of outdoor gamma level in Khorasan was also proposed. A Rados area monitoring system (AAM-90) including 10 intelligent RD-02 detector and all associated components were purchased. From 2003 gradually seven stations have been setup in Khorasan. For all seven stations monthly average and one hour daily average on four time intervals have been computed. Statistically no significant differences have been observed. This is also true for monthly averages. The overall average dose rate for present seven stations varies from 0.11 {mu}Sv{center_dot}h{sup -1} for Ferdows, to 0.04 {mu}Sv{center_dot}h{sup -1} for Dargaz. Based on our data, 50 minutes sample in any time interval is an accurate sample size to estimate out door Gamma dose rate.

Toossi, M. T. Bahreyni; Bayani, SH. [Environmental dosimetery laboratory, Medical Physics Research Center, Mashad University of Medical Sciences, Mashad (Iran, Islamic Republic of)

2008-08-07T23:59:59.000Z

279

Angular Signatures of Dark Matter in the Diffuse Gamma Ray Spectrum  

SciTech Connect (OSTI)

Dark matter annihilating in our Galaxy's halo and elsewhere in the universe is expected to generate a diffuse flux of gamma rays, potentially observable with next generation satellite-based experiments, such as GLAST. In this article, we study the signatures of dark matter in the angular distribution of this radiation. Pertaining to the extragalactic contribution, we discuss the effect of the motion of the solar system with respect to the cosmological rest frame, and anisotropies due to the structure of our local universe. For the gamma ray flux from dark matter in our own Galactic halo, we discuss the effects of the offset position of the solar system, the Compton-Getting effect, the asphericity of the Milky Way halo, and the signatures of nearby substructure. We explore the prospects for the detection of these features by the GLAST satellite and find that, if {approx} 10% or more of the diffuse gamma ray background observed by EGRET is the result of dark matter annihilations, then GLAST should be sensitive to anisotropies down to the 0.1% level. Such precision would be sufficient to detect many, if not all, of the signatures discussed in this paper.

Hooper, Dan; Serpico, Pasquale D.; /Fermilab

2007-02-01T23:59:59.000Z

280

Gamma-Ray Bursts  

E-Print Network [OSTI]

Gamma-ray bursts are the most luminous explosions in the Universe, and their origin and mechanism are the focus of intense research and debate. More than three decades after their discovery, and after pioneering breakthroughs from space and ground experiments, their study is entering a new phase with the recently launched Swift satellite. The interplay between these observations and theoretical models of the prompt gamma ray burst and its afterglow is reviewed.

P. Meszaros

2006-05-30T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

A supersymmetric model of gamma ray bursts  

E-Print Network [OSTI]

We propose a model for gamma ray bursts in which a star subject to a high level of fermion degeneracy undergoes a phase transition to a supersymmetric state. The burst is initiated by the transition of fermion pairs to sfermion pairs which, uninhibited by the Pauli exclusion principle, can drop to the ground state of minimum momentum through photon emission. The jet structure is attributed to the Bose statistics of sfermions whereby subsequent sfermion pairs are preferentially emitted into the same state (sfermion amplification by stimulated emission). Bremsstrahlung gamma rays tend to preserve the directional information of the sfermion momenta and are themselves enhanced by stimulated emission.

L. Clavelli; G. Karatheodoris

2005-08-08T23:59:59.000Z

282

First observations of Y(1S)->gamma pi(+)pi(-) and Y(1S)->gamma pi(0)pi(0)  

E-Print Network [OSTI]

We report on a study of exclusive radiative decays of the Y(1S) resonance collected with the CLEO II detector operating at the Cornell Electron Storage Ring. We present the first observation of the radiative decays Y(1S) --> gamma pi(+)pi(-) and Y(1...

Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Darling, C.; Davis, Robin E. P.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan; Zhou, L.

1999-01-01T23:59:59.000Z

283

Proposed Lymph Node Staging System Using the International Consensus Guidelines for Lymph Node Levels Is Predictive for Nasopharyngeal Carcinoma Patients From Endemic Areas Treated With Intensity Modulated Radiation Therapy  

SciTech Connect (OSTI)

Purpose: To propose a lymph node (N) staging system for nasopharyngeal carcinoma (NPC) based on the International Consensus Guidelines for lymph node (LN) levels and MRI-determined nodal variables. Methods and Materials: The MRI scans and medical records of 749 NPC patients receiving intensity modulated radiation therapy with or without chemotherapy were retrospectively reviewed. The prognostic significance of nodal level, laterality, maximal axial diameter, extracapsular spread, necrosis, and Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) size criteria were analyzed. Results: Nodal level and laterality were the only independent prognostic factors for distant failure and disease failure in multivariate analysis. Compared with unilateral levels Ib, II, III, and/or Va involvement (hazard ratio [HR] 1), retropharyngeal lymph node involvement alone had a similar prognostic value (HR 0.71; 95% confidence interval [CI] 0.43-1.17; P=.17), whereas bilateral levels Ib, II, III, and/or Va involvement (HR 1.65; 95% CI 1.06-2.58; P=.03) and levels IV, Vb, and/or supraclavicular fossa involvement (HR 3.47; 95% CI 1.92-6.29; P<.01) both significantly increased the HR for distant failure. Thus we propose that the N category criteria could be revised as follows: N0, no regional LN metastasis; N1, retropharyngeal lymph node involvement, and/or unilateral levels Ib, II, III, and/or Va involvement; N2, bilateral levels Ib, II, III, and/or Va involvement; N3, levels IV, Vb, and/or supraclavicular fossa involvement. Compared with the 7th edition of the UICC/AJCC criteria, the proposed N staging system provides a more satisfactory distinction between the HRs for regional failure, distant failure, and disease failure in each N category. Conclusions: The proposed N staging system defined by the International Consensus Guidelines and laterality is predictive and practical. However, because of no measurements of the maximal nodal diameter on MRI slices, the prognostic significance of LN size needs further evaluation.

Li, Wen-Fei; Sun, Ying; Mao, Yan-Ping; Chen, Lei; Chen, Yuan-Yuan; Chen, Mo [Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China)] [Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China); Liu, Li-Zhi [Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China)] [Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China); Lin, Ai-Hua [Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou (China)] [Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou (China); Li, Li [Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China)] [Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China); Ma, Jun, E-mail: majun2@mail.sysu.edu.cn [Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China)] [Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou (China)

2013-06-01T23:59:59.000Z

284

A comparison of the alpha and gamma radiolysis of CMPO  

SciTech Connect (OSTI)

The radiation chemistry of CMPO has been investigated using a combination of irradiation and analytical techniques. The {alpha}-, and {gamma}-irradiation of CMPO resulted in identical degradation rates (G-value, in {mu}mol Gy{sup -1}) for both radiation types, despite the difference in their linear energy transfer (LET). Similarly, variations in {gamma}-ray dose rates did not affect the degradation rate of CMPO. The solvent extraction behavior was different for the two radiation types, however. Gamma-irradiation resulted in steadily increasing distribution ratios for both forward and stripping extractions, with respect to increasing absorbed radiation dose. This was true for samples irradiated as a neat organic solution, or irradiated in contact with the acidic aqueous phase. In contrast, {alpha}-irradiated samples showed a rapid drop in distribution ratios for forward and stripping extractions, followed by essentially constant distribution ratios at higher absorbed doses. These differences in extraction behavior are reconciled by mass spectrometric examination of CMPO decomposition products under the different irradiation sources. Irradiation by {gamma}-rays resulted in the rupture of phosphoryl-methylene bonds with the production of phosphinic acid products. These species are expected to be complexing agents for americium that would result in higher distribution ratios. Irradiation by {alpha}-sources appeared to favor rupture of carbamoyl-methylene bonds with the production of less deleterious acetamide products.

Bruce J. Mincher; Stephen P. Mezyk; Gary Groenewold; Gracy Elias

2011-06-01T23:59:59.000Z

285

Courses on Synchrotron Radiation  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phases on &gamma;-Al2O3. |ID#:Synchrotron Radiation The following is

286

Neutron-driven gamma-ray laser  

DOE Patents [OSTI]

A lasing cylinder emits laser radiation at a gamma-ray wavelength of 0.87 .ANG. when subjected to an intense neutron flux of about 400 eV neutrons. A 250 .ANG. thick layer of Be is provided between two layers of 100 .ANG. thick layer of .sup.57 Co and these layers are supported on a foil substrate. The coated foil is coiled to form the lasing cylinder. Under the neutron flux .sup.57 Co becomes .sup.58 Co by neutron absorption. The .sup.58 Co then decays to .sup.57 Fe by 1.6 MeV proton emission. .sup.57 Fe then transitions by mesne decay to a population inversion for lasing action at 14.4 keV. Recoil from the proton emission separates the .sup.57 Fe from the .sup.57 Co and into the Be, where Mossbauer emission occurs at a gamma-ray wavelength.

Bowman, Charles D. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

287

Factorization in B to V gamma Decays  

SciTech Connect (OSTI)

The factorization properties of the radiative decays B {yields} V{gamma} are analyzed at leading order in 1/mb using the soft-collinear effective theory. It is shown that the decay amplitudes can be expressed in terms of a B {yields} V form factor evaluated at q{sup 2} = 0, light-cone distribution amplitudes of the B and V mesons, and calculable hard-scattering kernels. The renormalization-group equations in the effective theory are solved to resume perturbative logarithms of the different scales in the decay process. Phenomenological implications for the B {yields} K*{gamma} branching ratio, isospin asymmetry, and CP asymmetries are discussed, with particular emphasis on possible effects from physics beyond the Standard Model.

Becher, T

2005-03-28T23:59:59.000Z

288

Radiative Exchange Between Square Parallel Channels in a Concentric Monolith Structure  

E-Print Network [OSTI]

Mean gas heat capacity (J mol \\Gamma1 K \\Gamma1 ) E Radiation view factor (multichannel model) F; d combustor for a gas turbine engine, where temperatures may be as high as 1550 K [3] and radiative exchange an important role. Initially, this paper derives the system of integral equations that is used to model radia

Bath, University of

289

Optomechanical design of a prompt gamma reaction history diagnostic  

SciTech Connect (OSTI)

The National Ignition Facility and the Omega Laser Facility both have a need for measuring prompt gamma radiation as part of a nuclear diagnostic program. A new gamma-detection diagnostic using off-axis-parabolic mirrors has been built. Some new techniques were used in the design, construction, and tolerancing of this gamma ray diagnostic. Because of the wavelength requirement (250 to 700 nm), the optical element surface finishes were a key design consideration. The optical enclosure had to satisfy pressure safety concerns and shielding against electromagnetic interference induced by gammas and neutrons. Structural finite element analysis was needed to meet rigorous optical and safety requirements. The optomechanical design is presented. Alignment issues are also discussed.

Kaufman, Morris I; Frogget, Brent C; Tunnel, Thomas W; Cox, Brian; Frayer, Daniel K; Ali, Zaheer; Herrmann, Hans

2009-09-10T23:59:59.000Z

290

Optomechanical design of a prompt gamma reaction history diagnostic  

SciTech Connect (OSTI)

The National Ignition Facility and the Omega Laser Facility both have a need for measuring prompt gamma radiation as part of a nuclear diagnostic program. A new gamma-detection diagnostic using off-axis-parabolic mirrors has been built. Some new techniques were used in the design, construction, and tolerancing of this gamma ray diagnostic. Because of the wavelength requirement (250-700 nm), the optical element surface finishes were a key design consideration. The optical enclosure had to satisfy pressure safety concerns and shielding against electromagnetic interference induced by gammas and neutrons. Structural finite element analysis was needed to meet rigorous optical and safety requirements. The optomechanical design is presented. Alignment issues are also discussed.

Hermann, Hans W [Los Alamos National Laboratory; Kaufman, Morris I [Los Alamos National Laboratory; Malone, Robert M [NSTEC; Frogget, Brent C [NSTEC; Tunnell, Thomas W [NSTEC; Cox, Brian [NSTEC; Frayer, Daniel K [NSTEC; Ali, Zaheer [NSTEC; Stoeffl, Wolfgang [LLNL

2009-01-01T23:59:59.000Z

291

Neutron and gamma irradiation damage to organic materials.  

SciTech Connect (OSTI)

This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at < 200 C. In short, there are no gamma and neutron irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

White, Gregory Von, II; Bernstein, Robert

2012-04-01T23:59:59.000Z

292

High spins in gamma-soft nuclei  

SciTech Connect (OSTI)

Nuclei which are soft with respect to the ..gamma.. shape degree of freedom are expected to have many different structures coexisting in the near-yrast regime. In particular, the lowest rotational quasi-particle in a high-j shell exerts a strong polarizing effect on ..gamma... The ..gamma.. to which it drives is found to vary smoothly over a 180/sup 0/ range as the position of the Fermi level varies. This simple rule is seen to have a direct connection with the energy staggering of alternate spin states in rotational bands. A diagram is presented which provides a general theoretical reference for experimental tests of the relation between ..gamma.., spin staggering, configuration, and nucleon number. In a quasicontinuum spectrum, the coexistence of different structures are expected to make several unrelated features appear within any one slice of sum energy and multiplicity. However, it is also seen that the in-band moment of inertia may be similar for many bands of different ..gamma...

Leander, G.A.; Frauendorf, S.; May, F.R.

1982-01-01T23:59:59.000Z

293

Possibility to Determine the Astrophysical S-Factor for the Be-7(p,gamma)b-8 Radiative-Capture from Analysis of the Be-7(he-3,d)b-8 Reaction  

E-Print Network [OSTI]

PHYSICAL REVIEW C VOLUME 51, NUMBER 6 JUNE 1995 Possibility to determine the astrophysical S factor for the Be(p, p)sB radiative capture from analysis of the Be(sHe, d)sB reaction A. M. Mukhamedzhanov and R. E. Tribble Cyclotron Institute, Texas...) of the internal bound-state wave functions of B and Be, IsB'rB, (r) = ($?~~PsB), where r is the relative coordinate between the proton and the center of mass of Be, is approximated by S,&,B &P?, ?(r) . Here S887B is the spectroscopic factor of the configura...

Mukhamedzhanov, AM; Tribble, Robert E.; imofeyuk, N. K.

1995-01-01T23:59:59.000Z

294

Position-sensitive radiation monitoring (surface contamination monitor). Innovative technology summary report  

SciTech Connect (OSTI)

The Shonka Research Associates, Inc. Position-Sensitive Radiation Monitor both detects surface radiation and prepares electronic survey map/survey report of surveyed area automatically. The electronically recorded map can be downloaded to a personal computer for review and a map/report can be generated for inclusion in work packages. Switching from beta-gamma detection to alpha detection is relatively simple and entails moving a switch position to alpha and adjusting the voltage level to an alpha detection level. No field calibration is required when switching from beta-gamma to alpha detection. The system can be used for free-release surveys because it meets the federal detection level sensitivity limits requires for surface survey instrumentation. This technology is superior to traditionally-used floor contamination monitor (FCM) and hand-held survey instrumentation because it can precisely register locations of radioactivity and accurately correlate contamination levels to specific locations. Additionally, it can collect and store continuous radiological data in database format, which can be used to produce real-time imagery as well as automated graphics of survey data. Its flexible design can accommodate a variety of detectors. The cost of the innovative technology is 13% to 57% lower than traditional methods. This technology is suited for radiological surveys of flat surfaces at US Department of Energy (DOE) nuclear facility decontamination and decommissioning (D and D) sites or similar public or commercial sites.

Not Available

1999-06-01T23:59:59.000Z

295

An investigation of the electronic wave functions in solids by the Compton scattering of gamma rays  

E-Print Network [OSTI]

APPARATUS The instrument, which was successfully used to study the behavior of the broadening of the Compton-scattered radiation, produces monochromatic gamma rays continuously variable in energy by selective Compton scattering of gamma photons emitted... was calculated. The system was adjusted to span the energy of- interest, then a count was taken 137 by using the Cs source. The channel corresponding to the peak 137 of Cs radiation was recorded, thon the pulser setting correspond)+8 to 662 1'eV (gamma ray...

Nha, Sang Kyun

1968-01-01T23:59:59.000Z

296

Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride  

SciTech Connect (OSTI)

For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for nondestructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminumnitride-based transducer operating in a nuclear reactor are also presented. We demonstrate the tolerance of single-crystal piezoelectric aluminum nitride after fast and thermal neutron fluences of 1.85 × 1018 neutron/cm2 and 5.8 × 1018 neutron/cm2, respectively, and a gamma dose of 26.8 MGy. The radiation hardness of AlN is most evident from the unaltered piezoelectric coefficient d33, which measured 5.5 pC/N after a fast and thermal neutron exposure in a nuclear reactor core for over 120 MWh, in agreement with the published literature value. The results offer potential for improving reactor safety and furthering the understanding of radiation effects on materials by enabling structural health monitoring and NDE in spite of the high levels of radiation and high temperatures, which are known to destroy typical commercial ultrasonic transducers.

David A. Parks; Bernhard R. Tittmann

2014-07-01T23:59:59.000Z

297

Gamma ray bursts in their historic context  

E-Print Network [OSTI]

Gamma Ray Bursts In Their Historic Context Virginia TrimbleMD 20742 USA Abstract. Gamma ray bursts remained essentiallyalso applies to the gamma ray bursts. First, an observation

Trimble, V

2004-01-01T23:59:59.000Z

298

SAPPHiRE: a Small Gamma-Gamma Higgs Factory  

E-Print Network [OSTI]

A new particle with mass ~ 125 GeV that resembles the Higgs boson has recently been discovered by ATLAS and CMS. We propose a low-energy gamma-gamma collider as a cost- and time-efficient option for a Higgs factory capable of studying this particle in detail. In the past, this option has been suggested as a possible application of the CLIC two-beam accelerator technology (the CLIC Higgs Experiment, CLICHE) or as an option for the ILC. Here we propose a design based on a pair of \\sim 10 GeV recirculating Linacs (Small Accelerator for Photon-Photon Higgs production using Recirculating Electrons, SAPPHiRE) similar in design to those proposed for the LHeC. We present parameters for the e- beams and sketch a laser backscattering system capable of producing a gamma-gamma peak luminosity of 0.36 \\times 10^34/cm2/s with E_CM (gamma-gamma) \\sim 125 GeV. A gamma-gamma collider with such a luminosity could be used to measure accurately the mass, bbar, WW\\ast, and gamma-gamma decays of the Higgs boson. We also comment on possible synergies with other projects such as LHeC, the ILC or CLIC, and on other physics prospects in gamma-gamma and e-gamma collisions.

S. A. Bogacz; J. Ellis; L. Lusito; D. Schulte; T. Takahashi; M. Velasco; M. Zanetti; F. Zimmermann

2012-08-14T23:59:59.000Z

299

Defense-in-Depth, How Department of Energy Implements Radiation...  

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

Defense-in-Depth, How Department of Energy Implements Radiation Protection in Low Level Waste Disposal Defense-in-Depth, How Department of Energy Implements Radiation Protection in...

300

Results of mobile gamma scanning activities in St. Louis, Missouri  

SciTech Connect (OSTI)

From 1942 through approximately 1966, the Mallinckrodt Chemical Works operated four plants in St. Louis, Missouri, for the Manhattan Engineer District and the Atomic Energy Commission. A variety of production processes using uranium- and radium-bearing ore materials were performed at the plants. It is the policy of the DOE to verify that radiological conditions at such sites or facilities comply with current DOE guidelines. Guidelines for release and use of such sites have become more stringent as research has provided more information since previous cleanups. The Formerly Utilized Sites Remedial Action Program (FUSRAP) was established as part of that effort to confirm the closeout status of facilities under contract to agencies preceding DOE during early nuclear energy development. Under the FUSRAP program, the Mallinckrodt properties have been previously investigated to determine the extent of on-site radiological contamination. At the request of DOE, Oak Ridge National Laboratory (ORNL) conducted a survey in May 1990, of public roadways and suspected haul routes between the Mallinckrodt plant and storage sites in St. Louis to ensure that no residual radioactive materials were conveyed off-site. A mobile gamma scanning van with an on-board computer system was used to identify possible anomalies. Suspect areas are those displaying measurements deviating from gamma exposure rates identified as typical for radiologically unenhanced areas in the vicinity of the areas of interest. The instrumentation highlighted three anomaly locations each of which measured less than 1m{sup 2} in size. None of the slightly elevated radiation levels originated from material associated with former AEC-related processing operations in the area. The anomalies resulted from elevated concentrations of radionuclides present in phosphate fertilizers, increased thorium in road-base gravel, and emanations from the radioactive storage site near the Latty Avenue airport. 9 refs., 3 figs.

Rodriguez, R E; Witt, D A; Cottrell, W D; Carrier, R F

1991-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Cascade population of levels and probable phase transition in vicinity of the excitation energy ~0.5Bn of heavy nucleus  

E-Print Network [OSTI]

From the comparison of absolute intensities of the two-step gamma-cascades and known intensities of their primary and secondary transitions, the cascade and total population of about ~100 levels of 181Hf and 184,185,187W excited in thermal neutron capture was determined. These experimental results and intensities of two-step cascades to the low-lying levels of mentioned nuclei were reproduced in calculation using level densities with clearly expressed step-like structure. Radiative strength functions of the primary transitions following gamma-decay of these compound nuclei to the levels in the region of pointed structure are considerably enhanced. Moreover, population of levels below 3 MeV can be reproduced only with accounting for local and rather considerable increase in radiative strength functions of the secondary transitions to the levels in vicinities of break points in energy dependence of level density and significant decrease of that to lower-lying states. Simultaneous change in both level density and strength functions in the same excitation region of a nucleus corresponds to the definition of the second-order phase transition.

V. A. Bondarenko; J. Honzatko; V. A. Khitrov; Li Chol; Yu. E. Loginov; S. Eh. Malyutenkova; A. M. Sukhovoj; I. Tomandl

2004-06-28T23:59:59.000Z

302

Polarization mesurements of gamma ray bursts and axion like particles  

E-Print Network [OSTI]

A polarized gamma ray emission spread over a sufficiently wide energy band from a strongly magnetized astrophysical object like gamma ray bursts (GRBs) offers an opportunity to test the hypothesis of axion like particles (ALPs). Based on evidences of polarized gamma ray emission detected in several gamma ray bursts we estimated the level of ALPs induced dichroism, which could take place in the magnetized fireball environment of a GRB. This allows to estimate the sensitivity of polarization measurements of GRBs to the ALP-photon coupling. This sensitivity $\\gag\\le 2.2\\cdot 10^{-11} {\\rm GeV^{-1}}$ calculated for the ALP mass $m_a=10^{-3}~{\\rm eV}$ and MeV energy spread of gamma ray emission is competitive with the sensitivity of CAST and becomes even stronger for lower ALPs masses.

Andre Rubbia; Alexander Sakharov

2008-09-03T23:59:59.000Z

303

Hybrid model of GeV-TeV gamma ray emission from Galactic Center  

E-Print Network [OSTI]

The observations of high energy $\\gamma$-ray emission from the Galactic center (GC) by HESS, and recently by Fermi, suggest the cosmic ray acceleration in the GC and possibly around the supermassive black hole. In this work we propose a lepton-hadron hybrid model to explain simultaneously the GeV-TeV $\\gamma$-ray emission. Both electrons and hadronic cosmic rays were accelerated during the past activity of the GC. Then these particles would diffuse outwards and interact with the interstellar gas and background radiation field. The collisions between hadronic cosmic rays with gas is responsible to the TeV $\\gamma$-ray emission detected by HESS. With fast cooling in the strong radiation field, the electrons would cool down and radiate GeV photons through inverse Compton scattering off the soft background photons. This scenario provides a natural explanation of the observed GeV-TeV spectral shape of $\\gamma$-rays.

Yi-Qing Guo; Qiang Yuan; Cheng Liu; Ai-Feng Li

2014-09-14T23:59:59.000Z

304

Integrating fiber optic radiation dosimeter  

SciTech Connect (OSTI)

The purpose of this research effort was to determine the feasibility of forming a radiation sensor coupled to an optical fiber capable of measuring gamma photon, x-ray, and beta particle dose rates and integrated dose, and to construct a prototype dosimeter read-out system utilizing the fiber optic sensor. The key component of the prototype dosimeter system is a newly developed radiation sensitive storage phosphor. When this phosphor is excited by energetic radiation, a proportionate population of electron-hole pairs are created which become trapped at specific impurities within the phosphor. Trapped electrons can subsequently be stimulated optically with near-infrared at approximately 1 micrometer wavelength; the electrons can recombine with holes at luminescent centers to produce a luminescence which is directly proportional to the trapped electron population, and thus to the radiation exposure. By attaching the phosphor to the end of an optical fiber, it is possible to transmit both the IR optical stimulation and the characteristic phosphor luminescence through the fiber to and from the read-out instrument, which can be located far (e.g., kilometers) from the radiation field. This document reports on the specific design of the prototype system and its operating characteristics, including its sensitivity to various radiation dose rates and energies, its dynamic range, signal-to-noise ratio at various radiation intensities, and other system characteristics. Additionally, the radiation hardness of the phosphor and fiber are evaluated. 17 refs., 29 figs., 5 tabs.

Soltani, P.K.; Wrigley, C.Y.; Storti, G.M.; Creager, R.E.

1989-03-01T23:59:59.000Z

305

Determination of thermal neutron capture gamma yields  

E-Print Network [OSTI]

A method of analysing Ge(Li) thermal neutron capture gamma spectra to obtain total gamma yields has been developed. Tie method determines both the yields from the well resolved gamma peaks in a spectrum as well as the gamma ...

Harper, Thomas Lawrence

1969-01-01T23:59:59.000Z

306

Determination of thermal neutron capture gamma yields.  

E-Print Network [OSTI]

A method of analysing Ge(Li) thermal neutron capture gamma spectra to obtain total gamma yields has been developed. Tie method determines both the yields from the well resolved gamma peaks in a spectrum as well as the gamma ...

Harper, Thomas Lawrence

1969-01-01T23:59:59.000Z

307

Danger radiations  

ScienceCinema (OSTI)

Le conférencier Mons.Hofert parle des dangers et risques des radiations, le contrôle des zones et les précautions à prendre ( p.ex. film badge), comment mesurer les radiations etc.

None

2011-04-25T23:59:59.000Z

308

Gamma Ray Bursts  

E-Print Network [OSTI]

Gamma-ray bursts have been detected at photon energies up to tens of GeV. We review some recent developments in the X-ray to GeV photon phenomenology in the light of Swift and Fermi observations, and some of the theoretical models developed to explain them, with a view towards implications for C.T.A.

Peter Mészáros

2012-04-12T23:59:59.000Z

309

A Plasma Instability Theory of Gamma-Ray Burst Emission  

E-Print Network [OSTI]

A plasma instability theory is presented for the prompt radiation from gamma-ray bursts. In the theory, a highly relativistic shell interacts with the interstellar medium through the filamentation and the two-stream instabilities to convert bulk kinetic energy into electron thermal energy and magnetic field energy. The processes are not efficient enough to satisfy the Rankine-Hugoniot conditions, so a shock cannot form through this mechanism. Instead, the interstellar medium passes through the shell, with the electrons radiating during this passage. Gamma-rays are produced by synchrotron self-Compton emission. Prompt optical emission is also produced through this mechanism, while prompt radio emission is produced through synchrotron emission. The model timescales are consistent with the shortest burst timescales. To emit gamma-rays, the shell's bulk Lorentz factor must be greater than approximately 1000. For the radiative processes to be efficient, the interstellar medium density must satisfy a lower limit that is a function of the bulk Lorentz factor. Because the limits operate as selection effects, bursts that violate them constitute new classes. In particular, a class of optical and ultraviolet bursts with no gamma-ray emission should exist. The lower limit on the density of the interstellar medium is consistent with the requirements of the Compton attenuation theory, providing an explanation for why all burst spectra appear to be attenuated. Several tests of the theory are discussed, as are the next theoretical investigations that should be conducted.

J. J. Brainerd

1999-04-02T23:59:59.000Z

310

A Search for Gamma-Ray Bursts and Pulsars, and the Application of Kalman Filters to Gamma-Ray Reconstruction  

E-Print Network [OSTI]

Part I describes the analysis of periodic and transient signals in EGRET data. A method to search for the transient flux from gamma-ray bursts independent of triggers from other gamma-ray instruments is developed. Several known gamma-ray bursts were independently detected, and there is evidence for a previously unknown gamma-ray burst candidate. Statistical methods using maximum likelihood and Bayesian inference are developed and implemented to extract periodic signals from gamma-ray sources in the presence of significant astrophysical background radiation. The analysis was performed on six pulsars and three pulsar candidates. The three brightest pulsars, Crab, Vela, and Geminga, were readily identified, and would have been detected independently in the EGRET data without knowledge of the pulse period. No significant pulsation was detected in the three pulsar candidates. Eighteen X-ray binaries were examined. None showed any evidence of periodicity. In addition, methods for calculating the detection threshold of periodic flux modulation were developed. The future hopes of gamma-ray astronomy lie in the development of the Gamma-ray Large Area Space Telescope, or GLAST. Part II describes the development and results of the particle track reconstruction software for a GLAST science prototype instrument beam test. The Kalman filtering method of track reconstruction is introduced and implemented. Monte Carlo simulations, very similar to those used for the full GLAST instrument, were performed to predict the instrumental response of the prototype. The prototype was tested in a gamma-ray beam at SLAC. The reconstruction software was used to determine the incident gamma-ray direction. It was found that the simulations did an excellent job of representing the actual instrument response.

B. B. Jones

2002-02-04T23:59:59.000Z

311

Searches for Lepton Flavor Violation in the Decays tau+- ---> e+- gamma and tau+- ---> mu+- gamma  

SciTech Connect (OSTI)

Searches for lepton-flavor-violating decays of a {tau} lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 {+-} 7) x 10{sup 6} {tau} decays collected by the BABAR detector near the {Upsilon}(4S), {Upsilon}(3S) and {Upsilon}(2S) resonances. The searches yield no evidence of signals and they set upper limits on the branching fractions of {Beta}({tau}{sup {+-}} {yields} e{sup {+-}}{gamma}) < 3.3 x 10{sup -8} and {Beta}({tau}{sup {+-}} {yields} {mu}{sup {+-}}{gamma}) < 4.4 x 10{sup -8} at 90% confidence level.

Aubert, Bernard; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, David Nathan; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS; /more authors.; ,

2010-06-11T23:59:59.000Z

312

Instructions for calibrating gamma detectors using the Canberra-Nuclear Data Genie Gamma Spectroscopy System  

SciTech Connect (OSTI)

A straight forward protocol provides a way to guide the calibration of a gamma detector for a particular geometry and material. Several programs have used the Low Level Gamma Counting Facility of the Health and Ecological Assessment Division of the Lawrence Livermore National Laboratory to count a variety of large environmental samples contained in several unique geometries. The equipment and calibration requirements needed to analyze these types of samples are explained. This document describes the calibration protocol that has been developed and describes how it is used to calibrate the detectors.

Brunk, J.L.

1995-09-01T23:59:59.000Z

313

Developing a Methodology for Characterizing the Effects of Building Materials’ Natural Radiation Background on a Radiation Portal Monitoring System  

E-Print Network [OSTI]

, weather, and time of day. 6 Gamma rays are electromagnetic radiation emitted by excited nuclei in order for them to reach the ground state after decaying. Once emitted, these particles mainly interact with matter in three ways: photoelectric effect... and measured density were then used to define the MCNP material card for concrete. Pulse height tallies were used to determine the total gamma ray count rate in each of the four gamma detectors in the RPM. 5 CHAPTER II BACKGROUND II.A. Radiation...

Fitzmaurice, Matthew Blake 1988-

2012-11-06T23:59:59.000Z

314

Radiation absorption properties of different plaster samples  

SciTech Connect (OSTI)

Although the plaster is one of the oldest known synthetic building materials, nowadays, it is used as interior coating of walls and ceilings of buildings. Thus measuring its radiation shielding properties is vital. For this purpose, radiation absorption properties of different plaster samples in this study. The measurements have been performed using gamma spectrometer system which connected to 3'' Multiplication-Sign 3''NaI (TI) detector.

Akkurt, Iskender; Guenoglu, Kadir; Mavi, Betuel; K Latin-Small-Letter-Dotless-I l Latin-Small-Letter-Dotless-I ncarslan, Semsettin; Seven, Aysun [Suleyman Demirel University, Faculty of Arts and Sciences, Department of Physics, Isparta (Turkey); Amasya University, Faculty of Arts and Sciences, Department of Physics, Amasya (Turkey); Suleyman Demirel University, Faculty of Technical Education, Department of Construction Education, Isparta (Turkey)

2012-09-06T23:59:59.000Z

315

Constraints on GRB TeV Emission from the GeV Extragalactic Diffuse Gamma-Ray Flux  

E-Print Network [OSTI]

TeV gamma rays emitted by GRBs are converted into electron-positron pairs via interactions with the extragalactic infrared radiation fields. In turn the pairs produced, whose trajectories are randomized by magnetic fields, will inverse Compton scatter off the cosmic microwave background photons. The beamed TeV gamma ray flux from GRBs is thus transformed into a GeV isotropic gamma ray flux, which contributes to the total extragalactic gamma-ray background emission. Assuming a model for the extragalactic radiation fields, for the GRB redshift distribution and for the GRB luminosity function, we use the measured GeV extragalactic gamma-ray flux to set upper limits on the GRB emission in TeV gamma rays that is predicted in several models.

Casanova, S; Zhang, B; Zhang, Bing

2006-01-01T23:59:59.000Z

316

Design/installation and structural integrity assessment under the Federal Facility Agreement for Bethel Valley Low-Level Waste Collection and Transfer System upgrade for Building 2026 (High Radiation Level Analytical Laboratory) and Building 2099 (Monitoring and Control Station) at Oak Ridge National Laboratory  

SciTech Connect (OSTI)

This document presents a Design/Installation and Structural Integrity Assessment for a replacement tank system for portions of the Bethel Valley Low Level Waste (LLW) System, located at the Oak Ridge Reservation, Oak Ridge, Tennessee. This issue of the assessment covers the design aspects of the replacement tank system, and certifies that the design has sufficient structural integrity and is acceptable for the storing or treating of hazardous and/or radioactive substances. The present issue identifies specific activities that must be completed during the fabrication, installation, and testing of the replacement tank system in order to provide assurance that the final installation complies with governing requirements. Portions of the LLW system are several decades old, or older, and do not comply with current environmental protection regulations. Several subsystems of the LLW system have been designated to receive a state-of-the-art replacement and refurbishment. One such subsystem serves Building 2026, the High Radiation Level Analytical Laboratory. This assessment focuses on the scope of work for the Building 2026 replacement LLW Collection and Transfer System, including the provision of a new Monitoring and Control Station (Building 2099) to receive, store, and treat (adjust pH) low level radioactive waste.

Not Available

1994-10-01T23:59:59.000Z

317

Integrated nuclear radiation detector and monitor  

SciTech Connect (OSTI)

A battery powered device which can continuously monitor and detect nuclear radiation utilizing fully integrated circuitry and which is provided with an alarm which alerts persons when the radiation level exceeds a predetermined threshold.

Biehl, B.L.; Lieberman, S.I.

1982-06-22T23:59:59.000Z

318

Solution To The Gamma Ray Burst Mystery?  

E-Print Network [OSTI]

Photoexcitation and ionization of partially ionized heavy atoms in highly relativistic flows by interstellar photons, followed by their reemission in radiative recombination and decay, boost star-light into beamed $\\gamma$ rays along the flow direction. Repeated excitation/decay of highly relativistic baryonic ejecta from merger or accretion induced collapse of neutron stars in dense stellar regions (DSRs), like galactic cores, globular clusters and super star-clusters, can convert enough kinetic energy in such events in distant galaxies into cosmological gamma ray bursts (GRBs). The model predicts remarkably well all the main observed temporal and spectral properties of GRBs. Its success strongly suggests that GRBs are $\\gamma$ ray tomography pictures of DSRs in galaxies at cosmological distances with unprecedented resolution: A time resolution of $dt\\sim 1~ms$ in a GRB can resolve stars at a Hubble distance which are separated by only $D\\sim 10^{10}cm$. This is equivalent to the resolving power of an optical telescope with a diameter larger than one Astronomical Unit!

Nir J. Shaviv; Arnon Dar

1996-08-21T23:59:59.000Z

319

The Galactic gamma-ray club  

E-Print Network [OSTI]

The exclusive Galactic gamma-ray club has opened up to new members. Supernova remnants, pulsar wind nebulae, and massive binary systems hosting a compact object have recently joined the young pulsars as firmly established sources of gamma rays in the Milky Way. Massive young stellar clusters are on the waiting list to join the club. Only the fine imaging recently obtained at TeV energies could resolve specific sources. The samples are sparse, but raise exciting questions. The jet or pulsar-wind origin of the emission in binaries has been hotly debated, but it seems that both types of systems have been recently detected. The nature of the radiation in shock accelerators is still questioned: do nuclei contribute a lot, a little, or not to the gamma rays and what energy do they carry away from the shock budget? The acceleration process and the structural evolution of the pulsar winds are still uncertain. The magnetic field distribution in all these systems is a key, but poorly constrained, ingredient to model the multi-wavelength data, particle transport and electron ageing. It must, however, be determined in order to efficiently probe particle distributions and the acceleration mechanisms. The source samples soon to be expected from GLAST and the Cherenkov telescopes should bring new valuable test cases and they will, for the first time, shed statistical light on the collective behaviour of these different types of accelerators.

Isabelle A. Grenier

2008-04-02T23:59:59.000Z

320

SWEPP Gamma-Ray Spectrometer System software design description  

SciTech Connect (OSTI)

To assist in the characterization of the radiological contents of contract-handled waste containers at the Stored Waste Examination Pilot Plant (SWEPP), the SWEPP Gamma-Ray Spectrometer (SGRS) System has been developed by the Radiation Measurements and Development Unit of the Idaho National Engineering Laboratory. The SGRS system software controls turntable and detector system activities. In addition to determining the concentrations of gamma-ray-emitting radionuclides, this software also calculates attenuation-corrected isotopic mass ratios of-specific interest. This document describes the software design for the data acquisition and analysis software associated with the SGRS system.

Femec, D.A.; Killian, E.W.

1994-08-01T23:59:59.000Z

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


321

Radiation Damping of Shallow Foundations on Nonlinear Soil Medium  

E-Print Network [OSTI]

to the reduction of radiation damping due to soil yielding.since the reduced radiation damping at foundation level will2007 Paper No. 1150 RADIATION DAMPING OF SHALLOW FOUNDATIONS

Zhang, Jian; Tang, Yuchuan

2007-01-01T23:59:59.000Z

322

Delayed Gamma-Ray Spectroscopy for Spent Nuclear Fuel Assay  

SciTech Connect (OSTI)

High-energy, beta-delayed gamma-ray spectroscopy is investigated as a non-destructive assay technique for the determination of plutonium mass in spent nuclear fuel. This approach exploits the unique isotope-specific signatures contained in the delayed gamma-ray emission spectra detected following active interrogation with an external neutron source. A high fidelity modeling approach is described that couples radiation transport, analytical decay/depletion, and a newly developed gamma-ray emission source reconstruction code. Initially simulated and analyzed was a “one-pass” delayed gamma-ray assay that focused on the long-lived signatures. Also presented are the results of an independent study that investigated “pulsed mode” measurements, to capture the more isotope-specific, short-lived signatures. Initial modeling results outlined in this paper suggest that delayed gamma-ray assay of spent nuclear fuel assemblies can be accomplished with a neutron generator of sufficient strength and currently available gamma-ray detectors.

Campbell, Luke W.; Hunt, Alan W.; Ludewigt, Bernhard A.; Mozin, Vladimir V.

2012-04-01T23:59:59.000Z

323

Gamma doses from phospho-gypsum plaster-board  

SciTech Connect (OSTI)

The use of phospho-gypsum plaster-board and plaster cement in buildings as a substitute for natural gypsum may constitute an additional source of radiation exposure to both workers and members of the public, both from inhalation of radon progeny produced from radon which is exhaled from the plaster-board and from beta and gamma radiation produced by radioactive decay in the plaster-board. The calculations presented in this paper indicate that if phospho-gypsum sheets 1 cm thick containing a {sup 226}Ra concentration of 400 Bq kg{sup -1} are used to line the walls and ceiling of a room of dimensions up to 5 m {times} 5 m {times} 3 m, the annual effective dose from gamma radiation for a person continually occupying the room should not exceed approximately 0.13 mSv. This compares with a measured annual average effective dose from gamma radiation in Australian homes of 0.9 mSv. The annual effective dose from such thin sheets is directly proportional to the {sup 226}Ra concentration in the plaster-board. 13 refs., 6 figs.

O`Brien, R.S. [Australian Radiation Lab., Victoria (Australia)

1997-01-01T23:59:59.000Z

324

E-Print Network 3.0 - annihilation gamma rays Sample Search Results  

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

32 3 grid 74 94 3.05 ora SPEC ray tracing 650 array elements... .0 0.5 1.0 1.5 2.0 GammaGammaGammaGammaGammaGamma GammaGammaGammaGammaGammaGamma GammaGammaGamma...

325

E-Print Network 3.0 - atmospheric gamma rays Sample Search Results  

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

32 3 grid 74 94 3.05 ora SPEC ray tracing 650 array elements... .0 0.5 1.0 1.5 2.0 GammaGammaGammaGammaGammaGamma GammaGammaGammaGammaGammaGamma GammaGammaGamma...

326

Unidentified Gamma-Ray Sources: Hunting Gamma-Ray Blazars  

SciTech Connect (OSTI)

One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of the unidentified {gamma}-ray sources (UGSs). Despite the large improvements of Fermi in the localization of {gamma}-ray sources with respect to the past {gamma}-ray missions, about one third of the Fermi-detected objects are still not associated to low energy counterparts. Recently, using the Wide-field Infrared Survey Explorer (WISE) survey, we discovered that blazars, the rarest class of Active Galactic Nuclei and the largest population of {gamma}-ray sources, can be recognized and separated from other extragalactic sources on the basis of their infrared (IR) colors. Based on this result, we designed an association method for the {gamma}-ray sources to recognize if there is a blazar candidate within the positional uncertainty region of a generic {gamma}-ray source. With this new IR diagnostic tool, we searched for {gamma}-ray blazar candidates associated to the UGS sample of the second Fermi {gamma}-ray catalog (2FGL). We found that our method associates at least one {gamma}-ray blazar candidate as a counterpart each of 156 out of 313 UGSs analyzed. These new low-energy candidates have the same IR properties as the blazars associated to {gamma}-ray sources in the 2FGL catalog.

Massaro, F.; D'Abrusco, R.; Tosti, G.; Ajello, M.; Gasparrini, A.Paggi.D.

2012-04-02T23:59:59.000Z

327

Testing the millisecond pulsar scenario of the Galactic center gamma-ray excess with very high energy gamma-rays  

E-Print Network [OSTI]

The recent analyses of the Fermi Large Area Telescope data show an extended GeV $\\gamma$-ray excess on top of the expected diffuse background in the Galactic center region, which can be explained with annihilating dark matter or a population of millisecond pulsars (MSPs). We propose to observe the very high energy $\\gamma$-rays for distinguishing the MSP scenario from the dark matter scenario. The GeV $\\gamma$-ray MSPs should release most energy to the relativistic $e^{\\pm}$ wind, which will diffuse in the Galaxy and radiate TeV $\\gamma$-rays through inverse Compton scattering and bremsstrahlung processes. By calculating the spectrum and spatial distribution, we show that such emission is detectable with the next generation very high energy $\\gamma$-ray observatory, the Cherenkov Telescope Array (CTA), under reasonable model parameters. It is essential to search for the multi-wavelength counterparts to the GeV $\\gamma$-ray excess for solving this mystery in the high energy universe.

Qiang Yuan; Kunihito Ioka

2015-02-09T23:59:59.000Z

328

Remote radiation dosimetry  

DOE Patents [OSTI]

Disclosed are methods and apparatus for remotely measuring radiation levels. Such are particularly useful for measuring relatively high levels or dosages of radiation being administered in radiation therapy. They are also useful for more general radiation level measurements where remote sensing from the remaining portions of the apparatus is desirable. The apparatus uses a beam generator, such as a laser beam, to provide a stimulating beam. The stimulating beam is preferably of wavelengths shorter than 6 microns, or more advantageously less than 2 microns. The stimulating beam is used to stimulate a remote luminescent sensor mounted in a probe which emits stored luminescent energy resulting from exposure of the sensor to ionizing radiation. The stimulating beam is communicated to the remote luminescent sensor via a transmissive fiber which also preferably serves to return the emission from the luminescent sensor. The stimulating beam is advantageously split by a beam splitter to create a detector beam which is measured for power during a reading period during which the luminescent phosphor is read. The detected power is preferably used to control the beam generator to thus produce desired beam power during the reading period. The luminescent emission from the remote sensor is communicated to a suitable emission detector, preferably after filtering or other selective treatment to better isolate the luminescent emission. 8 figures.

Braunlich, P.F.; Tetzlaff, W.; Hegland, J.E.; Jones, S.C.

1991-03-12T23:59:59.000Z

329

Ionizing radiation detector  

DOE Patents [OSTI]

An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

Thacker, Louis H. (Knoxville, TN)

1990-01-01T23:59:59.000Z

330

Radiation measurements of uranium ingots from the electrometallurgical treatment of spent fuel.  

SciTech Connect (OSTI)

Radiation measurements and gamma spectroscopy analyses were made on numerous uranium ingots produced during the treatment of Experimental Breeder Reactor-II (EBR-II) spent nuclear fuel. The objective of these measurements was to provide background data for shielding concerns and potential process optimization. The uranium ingots resulted from the processing of both driver and blanket fuel by the electrometallurgical treatment process. The observed variation in the measurements was traced to the levels of certain fission product residues that remained in the uranium ingots produced during spent fuel treatment. A minor process change to hold the material at an elevated temperature for a specified length of time was found to significantly reduce concentrations of high-activity fission products and, thus the radiation field.

Westphal, B. R.; Liaw, J. R.; Krsul, J. R.; Maddison, D. W.; Jensen, B. A.

2003-03-24T23:59:59.000Z

331

How to Tell a Jet from a Balloon: A Proposed Test for Beaming in Gamma Ray Bursts  

E-Print Network [OSTI]

If gamma ray bursts are highly collimated, the energy requirements of each event may be reduced by several (~ 4-6) orders of magnitude, and the event rate increased correspondingly. Extreme conditions in gamma ray bursters lead to highly relativistic motions (bulk Lorentz factors Gamma > 100). This results in strong forward beaming of the emitted radiation in the observer's rest frame. Thus, all information on gamma ray bursts comes from those ejecta emitted in a narrow cone (opening angle 1/Gamma) pointing towards the observer. We are at present ignorant of whether there are ejecta outside that cone or not. The recent detection of longer wavelength transients following gamma ray bursts allows an empirical test of whether gamma ray bursts are collimated jets or spherical fireballs. The bulk Lorentz factor of the burst ejecta will decrease with time after the event, as the ejecta sweep up the surrounding medium. Thus, radiation from the ejecta is beamed into an ever increasing solid angle as the burst remnant evolves. It follows that if gamma ray bursts are highly collimated, many more optical and radio transients should be observed without associated gamma rays than with them. Published supernova searches may contain enough data to test the most extreme models of gamma ray beaming. We close with a brief discussion of other possible consequences of beaming, including its effect on the evolution of burst remnants.

James E. Rhoads

1997-09-15T23:59:59.000Z

332

Pulsed Photofission Delayed Gamma Ray Detection for Nuclear Material Identification  

SciTech Connect (OSTI)

Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. High-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. After photofission reactions, delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the fission signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. Isotopic composition measurement methods based on delayed gamma ray spectroscopy will be the primary focus of this work.

John Kavouras; Xianfei Wen; Daren R. Norman; Dante R. Nakazawa; Haori Yang

2012-11-01T23:59:59.000Z

333

Fermi GBM Observations of Terrestrial Gamma-ray Flashes  

SciTech Connect (OSTI)

Terrestrial Gamma-ray Flashes are short pulses of energetic radiation associated with thunderstorms and lightning. While the Gamma-ray Burst Monitor (GBM) on Fermi was designed to observe gamma-ray bursts, its large BGO detectors are excellent for observing TGFs. Using GBM, TGF pulses are seen to either be symmetrical or have faster rise time than fall times. Some TGFs are resolved into double, partially overlapping pulses. Using ground-based radio observations of lightning from the World Wide Lightning Location Network (WWLLN), TGFs and their associated lightning are found to be simultaneous to {approx_equal}40 {mu} s. The lightning locations are typically within 300 km of the sub-spacecraft point.

Briggs, Michael S. [CSPAR, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States)

2011-09-21T23:59:59.000Z

334

LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS  

E-Print Network [OSTI]

LASER-PLASMA-ACCELERATOR-BASED ?? COLLIDERS ? C. B.linear col- lider based on laser-plasma-accelerators arediscussed, and a laser-plasma-accelerator-based gamma-

Schroeder, C. B.

2010-01-01T23:59:59.000Z

335

Measurement of Radiation Damage on Silica Aerogel \\v Cerenkov Radiator  

E-Print Network [OSTI]

We measured the radiation damage on silica aerogel \\v Cerenkov radiators originally developed for the $B$-factory experiment at KEK. Refractive index of the aerogel samples ranged from 1.012 to 1.028. The samples were irradiated up to 9.8~MRad of equivalent dose. Measurements of transmittance and refractive index were carried out and these samples were found to be radiation hard. Deteriorations in transparency and changes of refractive index were observed to be less than 1.3\\% and 0.001 at 90\\% confidence level, respectively. Prospects of using aerogels under high-radiation environment are discussed.

S. K. Sahu et al

1996-04-11T23:59:59.000Z

336

Mon. Not. R. Astron. Soc. 401, 14651474 (2010) doi:10.1111/j.1365-2966.2009.15760.x Towards the properties of long gamma-ray burst progenitors  

E-Print Network [OSTI]

the properties of long gamma-ray burst progenitors with Swift data Xiao-Hong Cui,1 En-Wei Liang,2 Hou-Jun Lv,2 investigate the properties of both the prompt and X-ray afterglows of gamma-ray bursts (GRBs) in the burst . Key words: radiation mechanisms: non-thermal ­ gamma-rays: bursts. 1 INTRODUCTION One

Xu, Ren-Xin

337

The GAMMA-400 Space Mission  

E-Print Network [OSTI]

GAMMA-400 is a new space mission which will be installed on board the Russian space platform Navigator. It is scheduled to be launched at the beginning of the next decade. GAMMA-400 is designed to study simultaneously gamma rays (up to 3 TeV) and cosmic rays (electrons and positrons from 1 GeV to 20 TeV, nuclei up to 10$^{15}$-10$^{16}$ eV). Being a dual-purpose mission, GAMMA-400 will be able to address some of the most impelling science topics, such as search for signatures of dark matter, cosmic-rays origin and propagation, and the nature of transients. GAMMA-400 will try to solve the unanswered questions on these topics by high-precision measurements of the Galactic and extragalactic gamma-ray sources, Galactic and extragalactic diffuse emission and the spectra of cosmic-ray electrons + positrons and nuclei, thanks to excellent energy and angular resolutions.

Cumani, P; Bonvicini, V; Topchiev, N P; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, S; Bongi, M; Bottai, S; Castellini, G; Cattaneo, P W; Dedenko, G L; De Donato, C; Dogiel, V A; Gorbunov, M S; Gusakov, Yu V; Hnatyk, B I; Kadilin, V V; Kaplin, V A; Kaplun, A A; Kheymits, M D; Korepanov, V E; Larsson, J; Leonov, A A; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Menshenin, A L; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Popov, A V; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Taraskin, A A; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

2015-01-01T23:59:59.000Z

338

MODULAR CAUSTIC SIDE SOLVENT EXTRACTION UNIT (MCU) GAMMA MONITORS SYSTEM FINAL REPORT  

SciTech Connect (OSTI)

The Department of Energy (DOE) selected Caustic-Side Solvent Extraction (CSSX) as the preferred technology for the removal of radioactive cesium from High-Level Waste (HLW) at the Savannah River Site (SRS). Before the full-scale Salt Waste Processing Facility (SWPF) becomes operational, the Closure Business Unit (CBU) plans to process a portion of dissolved saltcake waste through a Modular CSSX Unit (MCU). This work was derived from Technical Task Request SP-TTR-2004-00013, ''Gamma Monitor for MCU''. The deliverables for this task are the hardware and software for the gamma monitors and a report summarizing the testing and acceptance of this equipment for use in the MCU. Gamma-ray monitors are required to: (1) Measure the Cs-137 concentration in the decontaminated salt solution before entering the DSS (Decontaminated Salt Solution) Hold Tank, (2) Measure the Cs-137 concentration in the strip effluent before entering the Strip Effluent Hold Tank, (3) Verify proper operation of the solvent extraction system by verifying material balance within the process (The DSS Hold Tank Cs-137 concentration will be very low and the Cs-137 concentration in the Strip Effluent Hold Tank will be fifteen times higher than the Cs-137 concentration in the Feed Tank.) Sodium iodide monitors are used to measure the Cs-137 concentration in the piping before the DSS Hold tank, while GM monitors are used for Cs-137 measurements before the Strip Effluent Hold Tank. Tungsten shields were designed using Monte Carlo calculations and fabricated to reduce the process background radiation at the detector positions. These monitors were calibrated with NIST traceable standards that were specially made to be the same as the piping being monitored. Since this gamma ray monitoring system is unique, specially designed software was written and acceptance tested by Savannah River National Laboratory personnel. The software is a LabView-based application that serves as a unified interface for controlling the monitor hardware and communicating with the host Distributed Control System (DCS). In order to provide user friendly software for the process personnel, the software was broken down into just a few software modules. These software modules are the Application Window, Detector Selection, Detector Configuration Settings, Background Counting, and Routine Data Acquisition. Instructions for using the software have been included in a user's manual that is appended to this report. The work presented in this report meets all of the requirements set forth in the project task plan to design and implement gamma ray monitors for the MCU. Additional setup and testing of the system will be required when it implemented in the process.

Casella, V

2005-12-15T23:59:59.000Z

339

Measurements of {psi}(2S) decays into {gamma}KK{pi} and {gamma}{eta}{pi}{sup +}{pi}{sup -}  

SciTech Connect (OSTI)

Radiative decays of the {psi}(2S) into {gamma}KK{pi} and {gamma}{eta}{pi}{sup +}{pi}{sup -} final states are studied using 14x10{sup 6} {psi}(2S) events collected with the BESII detector. Branching fractions or upper limits on the branching fractions of {psi}(2S) and {chi}{sub cJ} decays are reported. No significant signal for {eta}(1405)/{eta}(1475) is observed in the KK{pi} or {eta}{pi}{sup +}{pi}{sup -} mass spectra, and upper limits on the branching fractions of {psi}(2S){yields}{gamma}{eta}(1405)/{eta}(1475), {eta}(1405)/{eta}(1475){yields}KK{pi}, and {eta}{pi}{sup +}{pi}{sup -} are determined.

Ablikim, M.; Bai, J. Z.; Bian, J. G.; Cai, X.; Chen, H. S.; Chen, H. X.; Chen, J. C.; Chen, Jin; Chen, Y. B.; Chu, Y. P.; Cui, X. Z.; Deng, Z. Y.; Du, S. X.; Fang, J.; Fu, C. D.; Gao, C. S.; Gu, S. D.; Guo, Y. N.; Guo, Y. Q.; He, K. L. [Institute of High Energy Physics, Beijing 100049 (China)] (and others)

2006-10-01T23:59:59.000Z

340

RIS-M-2483 A PILOT INVESTIGATION OP NATORAL RADIATION IN DANISH HOUSES  

E-Print Network [OSTI]

EQUIVALENTS; DOSB RATES; DOSBMBTBRS; BTCHING; EXPERIMEN- TAL DATA; GAMMA RADIATION; HOUSES; NATURALRISø-M-2483 A PILOT INVESTIGATION OP NATORAL RADIATION IN DANISH HOUSES A. Sørensen, L. Bøtter radiation in Denmark. A passive cup dosemeter was designed containing CR39 track detectors and TLD

Note: This page contains sample records for the topic "gamma radiation levels" 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

GeV Emission from Collisional Magnetized Gamma Ray Bursts  

E-Print Network [OSTI]

Magnetic fields may play a dominant role in gamma-ray bursts, and recent observations by the Fermi satellite indicate that GeV radiation, when detected, arrives delayed by seconds from the onset of the MeV component. Motivated by this, we discuss a magnetically dominated jet model where both magnetic dissipation and nuclear collisions are important. We show that, for parameters typical of the observed bursts, such a model involving a realistic jet structure can reproduce the general features of the MeV and a separate GeV radiation component, including the time delay between the two. The model also predicts a multi-GeV neutrino component.

P. Mészáros; M. J. Rees

2011-04-26T23:59:59.000Z

342

ANALOGIES BETWEEN NEUTRON AND GAMMA-RAY IMAGING.  

SciTech Connect (OSTI)

Although the physics describing the interactions of neutrons with matter is quite different from that appropriate for hard x-rays and gamma rays, there are a number of similarities that allow analogous instruments to be developed for both types of ionizing radiation. A pinhole camera, for example, requires that the radiation obeys some form of geometrical optics, that a material can be found to absorb some of the radiation, and that a suitable position-sensitive detector can be built to record the spatial distribution of the incident radiation. Such conditions are met for photons and neutrons, even though the materials used are quite different. Neutron analogues of the coded-aperture gamma camera and the Compton camera have been demonstrated. Even though the Compton effect applies only to photons, neutrons undergo proton-recoil scattering that can provide similar directional information. There is also an analogy in the existence of an energy spectrum for the radiation used to produce the images, and which may allow different types of sources to be distinguished from each other and from background.

VANIER, P.E.

2006-08-13T23:59:59.000Z

343

Gamma Ray Burst Afterglow Observations.  

E-Print Network [OSTI]

??Gamma ray bursts (GRBs) are among the most luminous explosions in the universe. We present an overview of the observational history of GRBs and the… (more)

Updike, Adria

2007-01-01T23:59:59.000Z

344

Gamma-ray burst populations.  

E-Print Network [OSTI]

??Over the last fifty years the field of gamma-ray bursts has shown incredible growth, but the amassing of data has also left observers and theorists… (more)

Virgili, Francisco J.

2011-01-01T23:59:59.000Z

345

Strongly Polarized Optical Afterglows of Gamma-Ray Bursts  

E-Print Network [OSTI]

The optical afterglows of the gamma ray bursts can be strongly polarized, in principle up to tens of percents, if: (i) the afterglow is synchrotron radiation from an ultra-relativistic blast, (ii) the blast is beamed during the afterglow phase, i.e. the shock propagates within a narrow jet, (iii) we observe at the right time from the right viewing angle, (iv) magnetic fields parallel and perpendicular to the jet have different proper strengths.

Andrei Gruzinov

1999-05-21T23:59:59.000Z

346

Reversal of Hugoniot locus for strong shocks due to radiation  

SciTech Connect (OSTI)

Shock Hugoniot can be used to express the response of a material to shocks, and the compression ratio of the shock can be determined by the Hugoiot locus. When the shock is strong, it will become radiating, and the radiation will affect the Hugoniot. The role of radiation on the Hugoniot condition is studied in the paper. For the radiative flux-dominated shocks, the radiative flux if large enough may render the structure of the shock Hugoniot locus totally different with the case for the pure hydrodynamic shock: the two branches with one in quadrant I and the other in quadrant III are reversed into two in quadrants IV and II, respectively, correspondingly the compression ratio may be larger than the limiting value ({gamma}+1)/({gamma}-1) for ideal gases with index {gamma}. For the radiative shock in which the radiative heat wave propagates supersonically, a threshold value for the net radiative flux to the preshock is also defined which determines whether the Hugoniot locus is reversed and the compression ratio exceeds the limiting value. Numerical results also verify the reversal of the Hugoniot locus of the shocks if the net radiative flux to the preshock exceeds the threshold value.

Li Jiwei; Li Jinghong; Meng Guangwei [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

2011-04-15T23:59:59.000Z

347

Enhanced radiation resistant fiber optics  

DOE Patents [OSTI]

A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

Lyons, P.B.; Looney, L.D.

1993-11-30T23:59:59.000Z

348

Polarimetric performance of a Laue lens gamma-ray CdZnTe focal plane prototype  

SciTech Connect (OSTI)

A gamma-ray telescope mission concept [gamma ray imager (GRI)] based on Laue focusing techniques has been proposed in reply to the European Space Agency call for mission ideas within the framework of the next decade planning (Cosmic Vision 2015-2025). In order to optimize the design of a focal plane for this satellite mission, a CdZnTe detector prototype has been tested at the European Synchrotron Radiation Facility under an {approx}100% polarized gamma-ray beam. The spectroscopic, imaging, and timing performances were studied and in particular its potential as a polarimeter was evaluated. Polarization has been recognized as being a very important observational parameter in high energy astrophysics (>100 keV) and therefore this capability has been specifically included as part of the GRI mission proposal. The prototype detector tested was a 5 mm thick CdZnTe array with an 11x11 active pixel matrix (pixel area of 2.5x2.5 mm{sup 2}). The detector was irradiated by a monochromatic linearly polarized beam with a spot diameter of about 0.5 mm over the energy range between 150 and 750 keV. Polarimetric Q factors of 0.35 and double event relative detection efficiency of 20% were obtained. Further measurements were performed with a copper Laue monochromator crystal placed between the beam and the detector prototype. In this configuration we have demonstrated that a polarized beam does not change its polarization level and direction after undergoing a small angle (<1 deg.) Laue diffraction inside a crystal.

Curado da Silva, R. M. [Departmento de Fisica, Universidade de Coimbra, P-3000 Coimbra (Portugal); Center for Space Radiations, Univesite Catholique de Louvain (Belgium); Caroli, E.; Stephen, J. B.; Schiavone, F.; Donati, A.; Ventura, G. [Istituto di Astrofisica Spaziale e Fisica Cosmica-Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Pisa, A.; Auricchio, N.; Frontera, F. [Dipartimento di Fisica, Universita di Ferrara, Ferrara (Italy); Del Sordo, S. [Istituto di Astrofisica Spaziale e Fisica Cosmica-Palermo, Via Ugo La Malfa 153, 90146 Palermo (Italy); Honkimaeki, V. [European Synchrotron Radiation Facility, Grenoble (France); Trindade, A. M. F. [Departmento de Fisica, Universidade de Coimbra, P-3000 Coimbra (Portugal)

2008-10-15T23:59:59.000Z

349

Cooling of Accelerated Nucleons and Neutrino Emission in Gamma-Ray Bursts  

E-Print Network [OSTI]

Using Monte Carlo simulations, we demonstrate photopion production from Fermi-accelerated protons and the resulting neutrino production in gamma-ray bursts. Unless internal shocks occur at quite large distance from the center, ultra high-energy protons are depleted by photopion production and synchrotron radiation. Internal shocks at fiducial distance cause neutrino bursts, which accompany gamma-ray bursts originating from electromagnetic cascades.

Katsuaki Asano

2005-03-11T23:59:59.000Z

350

Blueshift Without Blueshift: Red Hole Gamma-Ray Burst Models Explain the Peak energy Distribution  

E-Print Network [OSTI]

Gamma-ray bursts are still a puzzle. In particular, the central engine, the total energy and the very narrow distribution of peak energies challenge model builders. We consider here an extreme model of gamma-ray bursts based on highly red- and blue-shifted positron annihilation radiation. The burst emerges from inside the red hole created by the complete gravitational collapse of the GRB progenitor.

James S. Graber

1999-12-15T23:59:59.000Z

351

Measurement of the p - anti-p ---> W gamma + X cross section at s**(1/2) = 1.96-TeV and WW gamma anomalous coupling limits  

SciTech Connect (OSTI)

The WW{gamma} triple gauge boson coupling parameters are studied using p{bar p} {yields} {ell}{nu}{gamma} + X({ell} = e, {mu}) events at {radical}s = 1.96 TeV. The data were collected with the D0 detector from an integrated luminosity of 162 pb{sup -1} delivered by the Fermilab Tevatron Collider. The cross section times branching fraction for p{bar p} {yields} W({gamma}) + X {yields} {ell}{nu}{gamma} + X with E{sub T}{sup {gamma}} > 8 GeV and {Delta}R{sub {ell}{gamma}} > 0.7 is 14.8 {+-} 1.6(stat) {+-} 1.0(syst) {+-} 1.0(lum) pb. The one-dimensional 95% confidence level limits on anomalous couplings are -0.88 < {Delta}{kappa}{sub {gamma}} < 0.96 and -0.20 < {lambda}{sub {gamma}} < 0.20.

Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, S.; Andrieu, B.; Arnoud, Y.; Askew, A.; /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao

2005-03-01T23:59:59.000Z

352

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

E-Print Network [OSTI]

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

Soebur Razzaque; Olga Mena; Charles D. Dermer

2008-11-24T23:59:59.000Z

353

Laser-driven hole boring and gamma-ray emission in high-density plasmas  

E-Print Network [OSTI]

Ion acceleration in laser-produced dense plasmas is a key topic of many recent investigations thanks to its potential applications. Besides, at forthcoming laser intensities ($I \\gtrsim 10^{23} \\text{W}\\,\\text{cm}^{-2}$) interaction of laser pulses with plasmas can be accompanied by copious gamma-ray emission. Here we demonstrate the mutual influence of gamma-ray emission and ion acceleration during relativistic hole boring in high-density plasmas with ultra-intense laser pulses. If gamma-ray emission is abundant, laser pulse reflection and hole-boring velocity are lower and gamma-ray radiation pattern is narrower than in the case of low emission. Conservation of energy and momentum allows one to elucidate the effects of gamma-ray emission which are more pronounced at higher hole-boring velocities.

Nerush, Evgeny

2014-01-01T23:59:59.000Z

354

Real time method and computer system for identifying radioactive materials from HPGe gamma-ray spectroscopy  

DOE Patents [OSTI]

A real-time method and computer system for identifying radioactive materials which collects gamma count rates from a HPGe gamma-radiation detector to produce a high-resolution gamma-ray energy spectrum. A library of nuclear material definitions ("library definitions") is provided, with each uniquely associated with a nuclide or isotope material and each comprising at least one logic condition associated with a spectral parameter of a gamma-ray energy spectrum. The method determines whether the spectral parameters of said high-resolution gamma-ray energy spectrum satisfy all the logic conditions of any one of the library definitions, and subsequently uniquely identifies the material type as that nuclide or isotope material associated with the satisfied library definition. The method is iteratively repeated to update the spectrum and identification in real time.

Rowland, Mark S. (Alamo, CA); Howard, Douglas E. (Livermore, CA); Wong, James L. (Dublin, CA); Jessup, James L. (Tracy, CA); Bianchini, Greg M. (Livermore, CA); Miller, Wayne O. (Livermore, CA)

2007-10-23T23:59:59.000Z

355

Measurement of the $\\Xi^0 \\rightarrow \\Lambda\\gamma$ Decay Asymmetry and Branching Fraction  

E-Print Network [OSTI]

In data taken with the NA48 experiment at the CERN SPS in 1999, 730 candidates of the weak radiative hyperon decay Xi0 -> Lambda gamma have been found with an estimated background of 58 +- 8 events. From these events the Xi0 -> Lambda gamma decay asymmetry has been determined to alpha(Xi0 -> Lambda gamma) = -0.78 +- 0.18_stat +- 0.06_syst, which is the first evidence of a decay asymmetry in Xi0 -> Lambda gamma. The branching fraction of the decay has been measured to be Br(Xi0 -> Lambda gamma) = (1.16 +- 0.05_stat +- 0.06_syst) x 10^-3.

Lai, A; Bevan, A; Dosanjh, R S; Gershon, T J; Hay, B; Kalmus, George Ernest; Lazzeroni, C; Munday, D J; Olaiya, E; Parker, M A; White, T O; Wotton, S A; Barr, G; Bocquet, G; Ceccucci, Augusto; Çuhadar-Dönszelmann, T; Cundy, Donald C; D'Agostini, Giulio; Doble, Niels T; Falaleev, V P; Gatignon, L; Gonidec, A; Gorini, B; Govi, G; Grafström, P; Kubischta, Werner; Lacourt, A; Norton, A; Palestini, S; Panzer-Steindel, B; Taureg, Hans; Velasco, M; Wahl, H; Cheshkov, C; Gaponenko, A N; Khristov, P Z; Kekelidze, V D; Madigozhin, D T; Molokanova, N A; Potrebenikov, Yu K; Tatishvili, G T; Tkachev, A L; Zinchenko, A I; Knowles, I; Martin, V; Sacco, R; Walker, A; Contalbrigo, M; Dalpiaz, Pietro; Duclos, J; Frabetti, P L; Gianoli, A; Martini, M; Petrucci, F; Savrié, M; Bizzeti, A; Calvetti, M; Collazuol, G; Graziani, G; Iacopini, E; Lenti, M; Martelli, F; Veltri, M; Becker, H G; Eppard, K; Eppard, M; Fox, H; Kalter, A; Kleinknecht, K; Koch, U; Köpke, L; Lopes da Silva, P; Marouelli, P; Pellmann, I A; Peters, A; Renk, B; Schmidt, S A; Schönharting, V; Schué, Yu; Wanke, R; Winhart, A; Wittgen, M; Chollet, J C; Fayard, L; Iconomidou-Fayard, L; Ocariz, J; Unal, G; Wingerter-Seez, I; Anzivino, Giuseppina; Cenci, P; Imbergamo, E; Lubrano, P; Mestvirishvili, A; Nappi, A; Pepé, M; Piccini, M; Bertanza, L; Carosi, R; Casali, R; Cerri, C; Cirilli, M; Costantini, F; Fantechi, R; Giudici, Sergio; Mannelli, I; Pierazzini, G M; Sozzi, M; Chèze, J B; Cogan, J; De Beer, M; Debu, P; Formica, A; Granier de Cassagnac, R; Mazzucato, E; Peyaud, B; Turlay, René; Vallage, B; Holder, M; Maier, A; Ziolkowski, M; Arcidiacono, R; Biino, C; Cartiglia, N; Guida, R; Marchetto, F; Menichetti, E; Pastrone, N; Nassalski, J P; Rondio, Ewa; Szleper, M; Wislicki, W; Wronka, S; Dibon, Heinz; Fischer, G; Jeitler, Manfred; Markytan, Manfred; Mikulec, I; Neuhofer, Günther; Pernicka, Manfred; Taurok, Anton; Widhalm, L

2004-01-01T23:59:59.000Z

356

High Energy Gamma-Ray Emission from Gamma-Ray Bursts - Before GLAST  

SciTech Connect (OSTI)

Gamma-ray bursts (GRBs) are short and intense emission of soft {gamma}-rays, which have fascinated astronomers and astrophysicists since their unexpected discovery in 1960s. The X-ray/optical/radio afterglow observations confirm the cosmological origin of GRBs, support the fireball model, and imply a long-activity of the central engine. The high-energy {gamma}-ray emission (> 20 MeV) from GRBs is particularly important because they shed some lights on the radiation mechanisms and can help us to constrain the physical processes giving rise to the early afterglows. In this work, we review observational and theoretical studies of the high-energy emission from GRBs. Special attention is given to the expected high-energy emission signatures accompanying the canonical early-time X-ray afterglow that was observed by the Swift X-ray Telescope. We also discuss the detection prospect of the upcoming GLAST satellite and the current ground-based Cerenkov detectors.

Fan, Yi-Zhong; Piran, Tsvi

2011-11-29T23:59:59.000Z

357

Sensitivity of the FERMI Detectors to Gamma-Ray Bursts from Evaporating Primordial Black Holes (PBHs)  

E-Print Network [OSTI]

Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. The Fermi Gamma-ray Space Telescope observatory offers increased sensitivity to the gamma-ray bursts produced by PBHs with an initial mass of $\\sim 5\\times 10^{14}$ g expiring today. PBHs are candidate progenitors of unidentified Gamma-Ray Bursts (GRBs) that lack X-ray afterglow. We propose spectral lag, which is the temporal delay between the high and low energy pulses, as an efficient method to identify PBH evaporation events with the Fermi Large Area Telescope (LAT).

T. N. Ukwatta; Jane H. MacGibbon; W. C. Parke; K. S. Dhuga; S. Rhodes; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris

2010-03-23T23:59:59.000Z

358

Discovery of TeV Gamma-Ray Emission from the Cygnus Region  

SciTech Connect (OSTI)

The diffuse gamma radiation arising from the interaction of cosmic ray particles with matter and radiation in the Galaxy is one of the few probes available to study the origin of the cosmic rays. Milagro is a water Cherenkov detector that continuously views the entire overhead sky. The large field-of-view combined with the long observation time makes Milagro the most sensitive instrument available for the study of large, low surface brightness sources such as the diffuse gamma radiation arising from interactions of cosmic radiation with interstellar matter. In this paper we present spatial and flux measurements of TeV gamma-ray emission from the Cygnus Region. The TeV image shows at least one new source MGRO J2019+37 as well as correlations with the matter density in the region as would be expected from cosmic-ray proton interactions. However, the TeV gamma-ray flux as measured at {approx}12 TeV from the Cygnus region (after excluding MGRO J2019+37) exceeds that predicted from a conventional model of cosmic ray production and propagation. This observation indicates the existence of either hard-spectrum cosmic-ray sources and/or other sources of TeV gamma rays in the region.

Abdo, A.A.; Allen, B.; Berley, D.; Blaufuss, E.; Casanova, S.; Chen, C.; Coyne, D.G.; Delay, R.S.; Dingus, B.L.; Ellsworth, R.W.; Fleysher, L.; Fleysher, R.; Gonzalez,; Goodman, J.A.; Hays, E.; Hoffman, C.M.; Kolterman, B.E.; Kelley, L.A.; Lansdell, C.P.; Linnemann, J.T.; McEnery, J.E.

2006-11-28T23:59:59.000Z

359

Discovery of TeV Gamma-Ray Emission from the Cygnus Region of the Galaxy  

E-Print Network [OSTI]

The diffuse gamma radiation arising from the interaction of cosmic ray particles with matter and radiation in the Galaxy is one of the few probes available to study the origin of the cosmic rays. Milagro is a water Cherenkov detector that continuously views the entire overhead sky. The large field-of-view combined with the long observation time makes Milagro the most sensitive instrument available for the study of large, low surface brightness sources such as the diffuse gamma radiation arising from interactions of cosmic radiation with interstellar matter. In this paper we present spatial and flux measurements of TeV gamma-ray emission from the Cygnus Region. The TeV image shows at least one new source MGRO J2019+37 as well as correlations with the matter density in the region as would be expected from cosmic-ray proton interactions. However, the TeV gamma-ray flux as measured at ~12 TeV from the Cygnus region (after excluding MGRO J2019+37) exceeds that predicted from a conventional model of cosmic ray production and propagation. This observation indicates the existence of either hard-spectrum cosmic-ray sources and/or other sources of TeV gamma rays in the region.

A. A. Abdo; B. Allen; D. Berley; E. Blaufuss; S. Casanova; C. Chen; D. G. Coyne; R. S. Delay; B. L. Dingus; R. W. Ellsworth; L. Fleysher; R. Fleysher; M. M. Gonzalez; J. A. Goodman; E. Hays; C. M. Hoffman; B. E. Kolterman; L. A. Kelley; C. P. Lansdell; J. T. Linnemann; J. E. McEnery; A. I. Mincer; I. V. Moskalenko; P. Nemethy; D. Noyes; J. M. Ryan; F. W. Samuelson; P. M. Saz Parkinson; M. Schneider; A. Shoup; G. Sinnis; A. J. Smith; A. W. Strong; G. W. Sullivan; V. Vasileiou; G. P. Walker; D. A. Williams; X. W. Xu; G. B. Yodh

2006-11-21T23:59:59.000Z

360

Comparison of 2D and 3D gamma analyses  

SciTech Connect (OSTI)

Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance, it must be noted that these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, in part because of the different search space available. In the present investigation, the authors compared the results of 2D and 3D gamma analysis (where both datasets were generated in the same manner) for clinical treatment plans. Methods: Fifty IMRT plans were selected from the authors’ clinical database, and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated dose distributions”) and Monte Carlo-recalculated (“reference dose distributions”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma, lower 95th percentile gamma value, and percentage of pixels passing gamma. Results: The average gamma, lower 95th percentile gamma value, and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. The average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a difference between the mean 2D and 3D results, ranging from 0.8% to 1.5%. The authors observed no appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs 3D). Conclusions: The authors found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. It must be noted that clinical 2D versus 3D datasets may have additional differences—for example, if 2D measurements are made with a different dosimeter than 3D measurements. Factors such as inherent dosimeter differences may be an important additional consideration to the extra dimension of available data that was evaluated in this study.

Pulliam, Kiley B.; Huang, Jessie Y.; Howell, Rebecca M.; Followill, David; Kry, Stephen F., E-mail: sfkry@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); Bosca, Ryan [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States)] [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States); O’Daniel, Jennifer [Department of Radiation Oncology, Duke University, Durham, North Carolina 27705 (United States)] [Department of Radiation Oncology, Duke University, Durham, North Carolina 27705 (United States)

2014-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Radiation dosimeter  

DOE Patents [OSTI]

A radiation detector readout circuit is provided which produces a radiation dose-rate readout from a detector even though the detector output may be highly energy dependent. A linear charge amplifier including an output charge pump circuit amplifies the charge signal pulses from the detector and pumps the charge into a charge storage capacitor. The discharge rate of the capacitor through a resistor is controlled to provide a time-dependent voltage which when integrated provides an output proportional to the dose-rate of radiation detected by the detector. This output may be converted to digital form for readout on a digital display.

Fox, Richard J. (Oak Ridge, TN)

1983-01-01T23:59:59.000Z

362

Radiation dosimeter  

DOE Patents [OSTI]

A radiation detector readout circuit is provided which produces a radiation dose-rate readout from a detector even through the detector output may be highly energy dependent. A linear charge amplifier including an output charge pump circuit amplifies the charge signal pulses from the detector and pumps the charge into a charge storage capacitor. The discharge rate of the capacitor through a resistor is controlled to provide a time-dependent voltage which when integrated provides an output proportional to the dose-rate of radiation detected by the detector. This output may be converted to digital form for readout on a digital display.

Fox, R.J.

1981-09-01T23:59:59.000Z

363

Radiative acceleration and transient, radiation-induced electric fields  

E-Print Network [OSTI]

The radiative acceleration of particles and the electrostatic potential fields that arise in low density plasmas hit by radiation produced by a transient, compact source are investigated. We calculate the dynamical evolution and asymptotic energy of the charged particles accelerated by the photons and the radiation-induced electric double layer in the full relativistic, Klein-Nishina regime. For fluxes in excess of $10^{27}$ ${\\rm erg} {\\rm cm}^{-2} {\\rm s}^{-1}$, the radiative force on a diluted plasma ($n\\la 10^{11}$ cm$^{-3}$) is so strong that electrons are accelerated rapidly to relativistic speeds while ions lag behind owing to their larger inertia. The ions are later effectively accelerated by the strong radiation-induced double layer electric field up to Lorentz factors $\\approx 100$, attainable in the case of negligible Compton drag. The asymptotic energies achieved by both ions and electrons are larger by a factor 2--4 with respect to what one could naively expect assuming that the electron-ion assembly is a rigidly coupled system. The regime we investigate may be relevant within the framework of giant flares from soft gamma-repeaters.

L. Zampieri; R. Turolla; L. Foschini; A. Treves

2003-04-14T23:59:59.000Z

364

Evidence for penguin-diagram decays: First observation of B -> K*(892)gamma  

E-Print Network [OSTI]

We have observed the decays B0 --> K*(892)0gamma and B- --> K*(892)-gamma, which are evidence for the quark-level process b --> sgamma. The average branching fraction is (4.5 +/- 1.5 +/- 0.9) x 10(-5). This value is ...

Ammar, Raymond G.; Ball, S.; Baringer, Philip S.; Coppage, Don; Copty, N.; Davis, Robin E. P.; Hancock, N.; Kelly, M.; Kwak, Nowhan; Lam, H.

1993-08-01T23:59:59.000Z

365

A Comparison of Simple Algorithms for Gamma-ray Spectrometers in Radioactive Source Search Applications  

SciTech Connect (OSTI)

Large variation in time-dependent ambient gamma-ray radiation challenges the search for radiation sources. A common strategy to reduce the effects of background variation is to raise detection thresholds, but at the price of reduced detection sensitivity. We present simple algorithms that both reduce background variation and maintain trip-wire detection sensitivity with gamma-ray spectrometry. The best-performing algorithms focus on the spectral shape over several energy bins using Spectral Comparison Ratios and dynamically predict background with the Kalman Filter.

Jarman, Kenneth D.; Runkle, Robert C.; Anderson, Kevin K.; Pfund, David M.

2008-03-01T23:59:59.000Z

366

High resolution x-ray and gamma ray imaging using diffraction lenses with mechanically bent crystals  

DOE Patents [OSTI]

A method for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation is provided. High quality mechanically bent diffracting crystals of 0.1 mm radial width are used for focusing the radiation and directing the radiation to an array of detectors which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for the use of a multi-component high resolution detector array and for narrow source and detector apertures.

Smither, Robert K. (Hinsdale, IL)

2008-12-23T23:59:59.000Z

367

Gamma neutron assay method and apparatus  

DOE Patents [OSTI]

The gamma neutron assay technique is an alternative method to standard safeguards techniques for the identification and assaying of special nuclear materials in a field or laboratory environment, as a tool for dismantlement and destruction of nuclear weapons, and to determine the isotopic ratios for a blend-down program on uranium. It is capable of determining the isotopic ratios of fissionable material from the spontaneous or induced fission of a sample to within approximately 0.5%. This is based upon the prompt coincidence relationships that occur in the fission process and the proton conservation and quasi-conservation of nuclear mass (A) that exists between the two fission fragments. The system is used in both passive (without an external neutron source and active (with an external neutron source) mode. The apparatus consists of an array of neutron and gamma-ray detectors electronically connected to determine coincident events. The method can also be used to assay radioactive waste which contains fissile material, even in the presence of a high background radiation field.

Cole, Jerald D. (Idaho Falls, ID); Aryaeinejad, Rahmat (Idaho Falls, ID); Greenwood, Reginald C. (Idaho Falls, ID)

1995-01-01T23:59:59.000Z

368

Gamma neutron assay method and apparatus  

DOE Patents [OSTI]

The gamma neutron assay technique is an alternative method to standard safeguards techniques for the identification and assaying of special nuclear materials in a field or laboratory environment, as a tool for dismantlement and destruction of nuclear weapons, and to determine the isotopic ratios for a blend-down program on uranium. It is capable of determining the isotopic ratios of fissionable material from the spontaneous or induced fission of a sample to within approximately 0.5%. This is based upon the prompt coincidence relationships that occur in the fission process and the proton conservation and quasi-conservation of nuclear mass (A) that exists between the two fission fragments. The system is used in both passive (without an external neutron source) and active (with an external neutron source) mode. The apparatus consists of an array of neutron and gamma-ray detectors electronically connected to determine coincident events. The method can also be used to assay radioactive waste which contains fissile material, even in the presence of a high background radiation field. 7 figures.

Cole, J.D.; Aryaeinejad, R.; Greenwood, R.C.

1995-01-03T23:59:59.000Z

369

Gamma-ray Laser and Radiation from Collimated Particles  

E-Print Network [OSTI]

The motion of channeled particles is accompanied by the photon emission. This feature can be used for the stimulated generation of high energy photons, but the required density of channeled particles must be very high.

Kovalev, Gennady V

2014-01-01T23:59:59.000Z

370

RADIATION SAFETY TRAINING MANUAL Radiation Safety Office  

E-Print Network [OSTI]

RADIATION SAFETY TRAINING MANUAL Radiation Safety Office 130 DeSoto Street G-7 Parran with sources of ionizing radiation are required to be instructed in the basic principles of radiation protection and the potential risks of ionizing radiation. Radiation Safety Office personnel provide

Sibille, Etienne

371

Appendix G. Radiation Appendix G. Radiation  

E-Print Network [OSTI]

-made sources. People are exposed to naturally occurring radiation constantly. For example, cosmic radiation of radiation and its effects on the environment and biological systems. Radiation comes from natural and humanAppendix G. Radiation #12;#12;Appendix G. Radiation This appendix presents basic facts about

Pennycook, Steve

372

Assessing exposure to radiation  

SciTech Connect (OSTI)

Since the founding of Lawrence Livermore National Laboratory, we have been world leaders in evaluating the risks associated with radiation. Ultrasensitive tools allow us not only to measure radionuclides present in the body but also to reconstruct the radiation dose from past nuclear events and to project the levels of radiation that will still be present in the body for 50 years after the initial intake. A variety of laboratory procedures, including some developed here, give us detailed information on the effects of radiation at the cellular level. Even today, we are re-evaluating the neutron dose resulting from the bombing at Hiroshima. Our dose reconstruction and projection capabilities have also been applied to studies of Nagasaki, Chernobyl, the Mayak industrial complex in the former Soviet Union, the Nevada Test Site, Bikini Atoll, and other sites. We are evaluating the information being collected on individuals currently working with radioactive material at Livermore and elsewhere as well as previously collected data on workers that extends back to the Manhattan Project.

Walter, K.

1997-01-01T23:59:59.000Z

373

NEW FERMI-LAT EVENT RECONSTRUCTION REVEALS MORE HIGH-ENERGY GAMMA RAYS FROM GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

Based on the experience gained during the four and a half years of the mission, the Fermi-LAT Collaboration has undertaken a comprehensive revision of the event-level analysis going under the name of Pass 8. Although it is not yet finalized, we can test the improvements in the new event reconstruction with the special case of the prompt phase of bright gamma-ray bursts (GRBs), where the signal-to-noise ratio is large enough that loose selection cuts are sufficient to identify gamma rays associated with the source. Using the new event reconstruction, we have re-analyzed 10 GRBs previously detected by the Large Area Telescope (LAT) for which an X-ray/optical follow-up was possible and found four new gamma rays with energies greater than 10 GeV in addition to the seven previously known. Among these four is a 27.4 GeV gamma ray from GRB 080916C, which has a redshift of 4.35, thus making it the gamma ray with the highest intrinsic energy ({approx}147 GeV) detected from a GRB. We present here the salient aspects of the new event reconstruction and discuss the scientific implications of these new high-energy gamma rays, such as constraining extragalactic background light models, Lorentz invariance violation tests, the prompt emission mechanism, and the bulk Lorentz factor of the emitting region.

Atwood, W. B. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Baldini, L. [Universita di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bregeon, J.; Pesce-Rollins, M.; Sgro, C.; Tinivella, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France); Chekhtman, A. [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); Cohen-Tanugi, J. [Laboratoire Univers et Particules de Montpellier, Universite Montpellier 2, CNRS/IN2P3, F-34095 Montpellier (France); Drlica-Wagner, A.; Omodei, N.; Rochester, L. S.; Usher, T. L. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Ra'anana 43537 (Israel); Longo, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Razzaque, S. [Department of Physics, University of Johannesburg, Auckland Park 2006 (South Africa); Zimmer, S., E-mail: melissa.pesce.rollins@pi.infn.it, E-mail: nicola.omodei@stanford.edu, E-mail: granot@openu.ac.il [Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden)

2013-09-01T23:59:59.000Z

374

The HAWC Gamma-Ray Observatory: Design, Calibration, and Operation  

E-Print Network [OSTI]

The High-Altitude Water Cherenkov Gamma Ray Observatory (HAWC) is under construction 4100 meters above sea level at Sierra Negra, Mexico. We describe the design and cabling of the detector, the characterization of the photomultipliers, and the timing calibration system. We also outline a next-generation detector based on the water Cherenkov technique.

Abeysekara, A U; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Díaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fernandez, A; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, L X; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-GarcIa, R; Marinelli, A; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nava, J; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivière, C; Rosa-González, D; Salazar, H; Salesa, F; Sanchez, F E; Sandoval, A; Santos, E; Schneider, M; Silich, S; Sinnis, G; Smith, A J; Sparks, K; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Villaseñor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H

2013-01-01T23:59:59.000Z

375

Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes  

SciTech Connect (OSTI)

The diffuse galactic {gamma}-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess {gamma}-ray emission {ge}1 GeV relative to diffuse galactic {gamma}-ray emission models consistent with directly measured CR spectra (the so-called 'EGRET GeV excess'). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse {gamma}-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10{sup o} {le} |b| {le} 20{sup o}. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic {gamma}-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

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

2012-04-11T23:59:59.000Z

376

Gamma and neutron detection modeling in the nuclear detection figure of merit (NDFOM) portal  

SciTech Connect (OSTI)

The Nuclear Detection Figure Of Merit (NDFOM) portal is a database of objects and algorithms for evaluating the performance of radiation detectors to detect nuclear material. This paper describes the algorithms used to model the physics and mathematics of radiation detection. As a first-principles end-to-end analysis system, it starts with the representation of the gamma and neutron spectral fluxes, which are computed with the particle and radiation transport code MCNPX. The gamma spectra emitted by uranium, plutonium, and several other materials of interest are described. The impact of shielding and other intervening material is computed by the method of build-up factors. The interaction of radiation with the detector material is computed by a detector response function approach. The construction of detector response function matrices based on MCNPX simulation runs is described in detail. Neutron fluxes are represented in a three group formulation to treat differences in detector sensitivities to thermal, epithermal, and fast neutrons.

Stroud, Phillip D [Los Alamos National Laboratory; Saeger, Kevin J [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

377

End-to-end calculation of the radiation characteristics of VVER-1000 spent fuel assemblies  

SciTech Connect (OSTI)

The results of end-to-end calculation of the radiation characteristics of VVER-1000 spent nuclear fuel are presented. Details of formation of neutron and gamma-radiation sources are analyzed. Distributed sources of different types of radiation are considered. A comparative analysis of calculated radiation characteristics is performed with the use of nuclear data from different ENDF/B and EAF files and ANSI/ANS and ICRP standards.

Linge, I. I.; Mitenkova, E. F., E-mail: mit@ibrae.ac.ru; Novikov, N. V. [Russian Academy of Sciences, Nuclear Safety Institute (Russian Federation)

2012-12-15T23:59:59.000Z

378

The beta decay of cesium 138 to levels in barium 138  

E-Print Network [OSTI]

. Coincidence electronics. 32 7. Gamma spectrum in coincidence with 409 ? 463 keV gate. 37 8. Gamma spectrum in coincidence with the 1436 keV gate. 39 9. Gamma spectrum in coincidence with the 2218 keV gate. 41 10. Gamma spectrum in coincidence... included 91 gamma rays and 18 levels and is shown in Fig, 1. MGMK found that their decay scheme confirmed that of BDMS with only minor changes in the energies of the levels. They also reported a state of 2880. 7 keV thought to be the 3 collective 6...

Fuller, Douglas Feril

1970-01-01T23:59:59.000Z

379

30TH INTERNATIONAL COSMIC RAY CONFERENCE Measuring TeV Gamma-Ray Diffuse Emission from the Galactic Plane with Milagro  

E-Print Network [OSTI]

mechanisms such as the annihilation of dark matter particles [5]. At TeV energies, Milagro has previously@lanl.gov Abstract: Diffuse gamma radiation produced in the interaction of cosmic-ray particles with matter and long observation time the Milagro Gamma-Ray Observatory ­ a water Cherenkov detector in New Mexico, USA

Moskalenko, Igor V.

380

Magnetic Structures in Gamma-Ray Burst Jets Probed by Gamma-Ray Polarization  

E-Print Network [OSTI]

We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB 110301A and GRB 110721A, observed with the Gamma-ray burst polarimeter (GAP) aboard IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of $\\Pi = 70 \\pm 22$% with statistical significance of $3.7 \\sigma$ for GRB 110301A, and $\\Pi = 84^{+16}_{-28}$% with $3.3 \\sigma$ confidence level for GRB 110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB 100826A, which showed a significant change of polarization angle, as reported in Yonetoku et al. (2011). Synchrotron emission model can be consistent with all the data of the three GRBs, while photospheric quasi-thermal emission model is not favorable. We suggest that magnetic field structures in the emission region are globally-ordered fields advected from the central engine.

Daisuke Yonetoku; Toshio Murakami; Shuichi Gunji; Tatehiro Mihara; Kenji Toma; Yoshiyuki Morihara; Takuya Takahashi; Yudai Wakashima; Hajime Yonemochi; Tomonori Sakashita; Noriyuki Toukairin; Hirofumi Fujimoto; Yoshiki Kodama

2012-08-27T23:59:59.000Z

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381

MAGNETIC STRUCTURES IN GAMMA-RAY BURST JETS PROBED BY GAMMA-RAY POLARIZATION  

SciTech Connect (OSTI)

We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB 110301A and GRB 110721A, observed with the gamma-ray burst polarimeter (GAP) on borad the IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of {Pi} = 70 {+-} 22% with statistical significance of 3.7{sigma} for GRB 110301A, and {Pi} = 84{sup +16}{sub -28}% with 3.3{sigma} confidence level for GRB 110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB 100826A, which showed a significant change of polarization angle, as reported in Yonetoku et al. Synchrotron emission model can be consistent with the data of the three GRBs, while the photospheric quasi-thermal emission model is not favored. We suggest that magnetic field structures in the emission region are globally ordered fields advected from the central engine.

Yonetoku, Daisuke; Murakami, Toshio; Morihara, Yoshiyuki; Takahashi, Takuya; Wakashima, Yudai; Yonemochi, Hajime; Sakashita, Tomonori; Fujimoto, Hirofumi; Kodama, Yoshiki [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan); Gunji, Shuichi; Toukairin, Noriyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12, Koshirakawa, Yamagata, Yamagata 990-8560 (Japan); Mihara, Tatehiro [Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198 (Japan); Toma, Kenji, E-mail: yonetoku@astro.s.kanazawa-u.ac.jp [Department of Earth and Space Science, Osaka University, Toyonaka 560-0043 (Japan)

2012-10-10T23:59:59.000Z

382

COMPACT CdZnTe-BASED GAMMA CAMERA FOR PROSTATE CANCER IMAGING  

SciTech Connect (OSTI)

In this paper, we discuss the design of a compact gamma camera for high-resolution prostate cancer imaging using Cadmium Zinc Telluride (CdZnTe or CZT) radiation detectors. Prostate cancer is a common disease in men. Nowadays, a blood test measuring the level of prostate specific antigen (PSA) is widely used for screening for the disease in males over 50, followed by (ultrasound) imaging-guided biopsy. However, PSA tests have a high false-positive rate and ultrasound-guided biopsy has a high likelihood of missing small cancerous tissues. Commercial methods of nuclear medical imaging, e.g. PET and SPECT, can functionally image the organs, and potentially find cancer tissues at early stages, but their applications in diagnosing prostate cancer has been limited by the smallness of the prostate gland and the long working distance between the organ and the detectors comprising these imaging systems. CZT is a semiconductor material with wide band-gap and relatively high electron mobility, and thus can operate at room temperature without additional cooling. CZT detectors are photon-electron direct-conversion devices, thus offering high energy-resolution in detecting gamma rays, enabling energy-resolved imaging, and reducing the background of Compton-scattering events. In addition, CZT material has high stopping power for gamma rays; for medical imaging, a few-mm-thick CZT material provides adequate detection efficiency for many SPECT radiotracers. Because of these advantages, CZT detectors are becoming popular for several SPECT medical-imaging applications. Most recently, we designed a compact gamma camera using CZT detectors coupled to an application-specific-integrated-circuit (ASIC). This camera functions as a trans-rectal probe to image the prostate gland from a distance of only 1-5 cm, thus offering higher detection efficiency and higher spatial resolution. Hence, it potentially can detect prostate cancers at their early stages. The performance tests of this camera have been completed. The results show better than 6-mm resolution at a distance of 1 cm. Details of the test results are discussed in this paper.

CUI, Y.; LALL, T.; TSUI, B.; YU, J.; MAHLER, G.; BOLOTNIKOV, A.; VASKA, P.; DeGERONIMO, G.; O'CONNOR, P.; MEINKEN, G.; JOYAL, J.; BARRETT, J.; CAMARDA, G.; HOSSAIN, A.; KIM, K.H.; YANG, G.; POMPER, M.; CHO, S.; WEISMAN, K.; SEO, Y.; BABICH, J.; LaFRANCE, N.; AND JAMES, R.B.

2011-10-23T23:59:59.000Z

383

Study Z gamma events and limits on anomalous ZZ gamma and Z gamma gamma couplings in pp(-) collisions at root s=1.96 Tev  

E-Print Network [OSTI]

We present a measurement of the Z gamma production cross section and limits on anomalous ZZ gamma and Z gamma gamma couplings for form-factor scales of Lambda=750 and 1000 GeV. The measurement is based on 138 (152) candidates ...

Baringer, Philip S.; Bean, Alice; Christofek, L.; Coppage, Don; Gardner, J.; Hensel, Carsten; Jabeen, S.; Wilson, Graham Wallace

2005-07-01T23:59:59.000Z

384

Ionizing Radiation Promotes Migration and Invasion of Cancer Cells Through Transforming Growth Factor-Beta-Mediated Epithelial-Mesenchymal Transition  

SciTech Connect (OSTI)

Purpose: To examine whether ionizing radiation enhances the migratory and invasive abilities of cancer cells through transforming growth factor (TGF-{beta})-mediated epithelial-mesenchymal transition (EMT). Methods and Materials: Six cancer cell lines originating from different human organs were irradiated by {sup 60}Co {gamma}-ray at a total dose of 2 Gy, and the changes associated with EMT, including morphology, EMT markers, migration and invasion, were observed by microscope, Western blot, immunofluorescence, scratch assay, and transwell chamber assay, respectively. Then the protein levels of TGF-{beta} in these cancer cells were detected by enzyme-linked immunosorbent assay, and the role of TGF-{beta} signaling pathway in the effect of ionizing radiation on EMT was investigate by using the specific inhibitor SB431542. Results: After irradiation with {gamma}-ray at a total dose of 2 Gy, cancer cells presented the mesenchymal phenotype, and compared with the sham-irradiation group the expression of epithelial markers was decreased and of mesenchymal markers was increased, the migratory and invasive capabilities were strengthened, and the protein levels of TGF-{beta} were enhanced. Furthermore, events associated with EMT induced by IR in A549 could be reversed through inhibition of TGF-{beta} signaling. Conclusions: These results suggest that EMT mediated by TGF-{beta} plays a critical role in IR-induced enhancing of migratory and invasive capabilities in cancer cells.

Zhou Yongchun [Department of Radiation Oncology, Xijing Hospital Fourth Military Medical University, Xi'an (China); Department of Radiation Medicine, College of Preventive Medicine, Xijing Hospital Fourth Military Medical University, Xi'an (China); Liu Junye; Li Jing; Zhang Jie [Department of Radiation Medicine, College of Preventive Medicine, Xijing Hospital Fourth Military Medical University, Xi'an (China); Xu Yuqiao [Department of Pathology, Xijing Hospital Fourth Military Medical University, Xi'an (China); Zhang Huawei; Qiu Lianbo; Ding Guirong [Department of Radiation Medicine, College of Preventive Medicine, Xijing Hospital Fourth Military Medical University, Xi'an (China); Su Xiaoming [Department of Radiation Oncology, 306th Hospital of PLA, Beijing (China); Mei Shi [Department of Radiation Oncology, Xijing Hospital Fourth Military Medical University, Xi'an (China); Guo Guozhen, E-mail: guozhenguo@hotmail.com [Department of Radiation Medicine, College of Preventive Medicine, Xijing Hospital Fourth Military Medical University, Xi'an (China)

2011-12-01T23:59:59.000Z

385

Radiation receiver  

DOE Patents [OSTI]

The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles. 5 figs.

Hunt, A.J.

1983-09-13T23:59:59.000Z

386

Radiation receiver  

DOE Patents [OSTI]

The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles.

Hunt, Arlon J. (Oakland, CA)

1983-01-01T23:59:59.000Z

387

Modeling gamma-ray bursts.  

E-Print Network [OSTI]

??Discovered serendipitously in the late 1960s, gamma-ray bursts (GRBs) are huge explosions of energy that happen at cosmological distances. They provide a grand physical playground… (more)

Maxham, Amanda

2011-01-01T23:59:59.000Z

388

Gamma-Ray Burst Lines  

E-Print Network [OSTI]

The evidence for spectral features in gamma-ray bursts is summarized. As a guide for evaluating the evidence, the properties of gamma-ray detectors and the methods of analyzing gamma-ray spectra are reviewed. In the 1980's, observations indicated that absorption features below 100 keV were present in a large fraction of bright gamma-ray bursts. There were also reports of emission features around 400 keV. During the 1990's the situation has become much less clear. A small fraction of bursts observed with BATSE have statistically significant low-energy features, but the reality of the features is suspect because in several cases the data of the BATSE detectors appear to be inconsistent. Furthermore, most of the possible features appear in emission rather than the expected absorption. Analysis of data from other instruments has either not been finalized or has not detected lines.

Michael S. Briggs

1999-10-20T23:59:59.000Z

389

Gamma-RayGamma-Ray Bursts: from SwiftBursts: from Swift  

E-Print Network [OSTI]

Gamma-RayGamma-Ray Bursts: from SwiftBursts: from Swift to GLASTto GLAST Bing ZhangBing ZhangGehrels, et al), et al) #12;Gamma-ray bursts: the mostGamma-ray bursts: the most violent explosions fireball central photosphere internal external shocks engine (shocks) (reverse) (forward) gamma-ray UV

California at Santa Cruz, University of

390

Gamma Ray Bursts and CETI  

E-Print Network [OSTI]

Gamma ray burst sources are isotropically distributed. They could be located at distances $\\sim 1000$ AU. (Katz \\cite{JK92}) GRB signals have many narrow peaks that are unresolved at the millisecond time resolution of existing observations. \\cite{JK87} CETI could use stars as gravitational lenses for interstellar gamma ray laser beam communication. Much better time resolution of GRB signals could rule out (or confirm?) the speculative hypothesis that GRB = CETI.

Frank D. Smith Jr

1993-02-10T23:59:59.000Z

391

Gamma-ray probes of dark matter substructure  

SciTech Connect (OSTI)

The substructure content of dark matter halos is interesting because it can be affected by complex galaxy physics and dark matter particle physics. However, observing the small scale structure of dark matter is a challenge. The subhalo abundance (mass function, minimum mass) and morphology (density profile, subhalo shape, subsubstructure) contain information about complex astrophysics (halo formation processes) and new exotic fundamental physics (dark matter interactions). Indirect detection of dark matter annihilation radiation (DMAR) in gamma rays may be the most direct method for observing small scale structure. I outline the ways in which gamma rays may probe halo substructure. If substructure is bountiful, it may be responsible for the eventual discovery of DMAR, for instance in galaxy clusters or the diffuse gamma-ray background. Otherwise, the observation of DMAR in places without much substructure, such as the Galactic center, would lead to strict limits on the properties of small scale structure. Properties of the gamma-ray angular power spectrum will also provide information or constraints on Milky Way halo substructure.

Campbell, Sheldon [Department of Physics and Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, 191 W. Woodruff Ave., Columbus, OH 43210 (United States)

2014-06-24T23:59:59.000Z

392

Frequency ratio method for seismic modeling of Gamma Doradus stars  

E-Print Network [OSTI]

A method for obtaining asteroseismological information of a Gamma Doradus oscillating star showing at least three pulsation frequencies is presented. This method is based on a first-order asymptotic g-mode expression, in agreement with the internal structure of Gamma Doradus stars. The information obtained is twofold: 1) a possible identification of the radial order n and degree l of observed frequencies (assuming that these have the same l), and 2) an estimate of the integral of the buoyancy frequency (Brunt-Vaisala) weighted over the stellar radius along the radiative zone. The accuracy of the method as well as its theoretical consistency are also discussed for a typical Gamma Doradus stellar model. Finally, the frequency ratios method has been tested with observed frequencies of the Gamma Doradus star HD 12901. The number of representative models verifying the complete set of constraints (the location in the HR diagram, the Brunt-Vaisala frequency integral, the observed metallicity and frequencies and a re...

Moya, A; Amado, P J; Martin-Ruiz, S; Garrido, R

2004-01-01T23:59:59.000Z

393

Contribution of GRB Emission to the GeV Extragalactic Diffuse Gamma-Ray Flux  

E-Print Network [OSTI]

TeV gamma rays emitted by GRBs are converted into electron-positron pairs via interactions with the extragalactic infrared radiation fields. In turn the pairs produced, whose trajectories are randomized by magnetic fields, will inverse Compton scatter off the cosmic microwave background photons. The beamed TeV gamma ray flux from GRBs is thus transformed into a GeV isotropic gamma ray flux, which contributes to the total extragalactic gamma-ray background emission. Assuming a model for the extragalactic radiation fields, for the GRB redshift distribution and for the GRB luminosity function, we evaluate the contribution of the GRB prompt and scattered emissions to the measured extragalactic gamma-ray flux. To estimate this contribution we optimistically require that the energy flux at TeV energies is about 10 times stronger than the energy flux at MeV energies. The resulting gamma-ray diffuse background is only a small fraction of what is observed, allowing blazars and other sources to give the dominant contribution.

S. Casanova; B. L. Dingus; Bing Zhang

2006-11-03T23:59:59.000Z

394

A Case Study Correlating Innovative Gamma Ray Scanning Detection Systems Data to Surface Soil Gamma Spectrometry Results - 13580  

SciTech Connect (OSTI)

HydroGeoLogic (HGL), Inc. completed a United States Environmental Protection Agency (USEPA) study to characterize radiological contamination at a site near Canoga Park, California. The characterized area contained 470 acres including the site of a prototype commercial nuclear reactor and other nuclear design, testing, and support operations from the 1950's until 1988 [1]. The site history included radiological releases during operation followed by D and D activities. The characterization was conducted under an accelerated schedule and the results will support the project remediation. The project has a rigorous cleanup to background agenda and does not allow for comparison to risk-based guidelines. To target soil sample locations, multiple lines of evidence were evaluated including a gamma radiation survey, geophysical surveys, historical site assessment, aerial photographs, and former worker interviews. Due to the time since production and decay, the primary gamma emitting radionuclide remaining is cesium-137 (Cs-137). The gamma ray survey covered diverse, rugged terrain using custom designed sodium iodide thallium-activated (NaI(Tl)) scintillation detection systems. The survey goals included attaining 100% ground surface coverage and detecting gamma radiation as sensitively as possible. The effectiveness of innovative gamma ray detection systems was tested by correlating field Cs-137 static count ratios to Cs-137 laboratory gamma spectrometry results. As a case study, the area encompassing the former location of the first nuclear power station in the U. S. was scanned, and second by second global positioning system (GPS)-linked gamma spectral data were evaluated by examining total count rate and nuclide-specific regions of interest. To compensate for Compton scattering from higher energy naturally occurring radionuclides (U-238, Th-232 and their progeny, and K-40), count rate ratios of anthropogenic nuclide-specific regions of interest to the total count rate were calculated. From the scanning data, locations with observed Cs-137 ratios exceeding six standard deviations above the mean ratio were mapped in high resolution [2]. Field teams returned to those locations to collect static count measurements using the same detection systems. Soil surface samples were collected at 30 locations and analyzed for Cs-137. An exponential correlation was identified between Cs-137 concentrations in surface soil and field-scanned Cs-137 ratios. The data indicate field minimum detectable concentration (MDC) of Cs-137 at 0.02 Bq/g (0.5 pCi/g) or lower depending on contaminant distribution in soil. (authors)

Thompson, Shannon; Rodriguez, Rene; Billock, Paul [HydroGeoLogic, Inc., 11107 Sunset Hills Road, Suite 400, Reston, VA 20190 (United States)] [HydroGeoLogic, Inc., 11107 Sunset Hills Road, Suite 400, Reston, VA 20190 (United States); Lit, Peter [Nomad Science Group, 7738 Nautilus Shell Street, Las Vegas, NV 89139 (United States)] [Nomad Science Group, 7738 Nautilus Shell Street, Las Vegas, NV 89139 (United States)

2013-07-01T23:59:59.000Z

395

Directional correlation measurements for gamma transitions in /sup 127/Te  

SciTech Connect (OSTI)

The directional correlation of coincident ..gamma.. transitions in /sup 127/Te has been measured following the ..beta../sup -/ decay of /sup 127/Sb (T/sub 1/2/ = 3.9 d) using Ge(Li)-Ge(Li) and Ge(Li)-NaI(T1) gamma spectrometers. Measurements have been carried out for 14 gamma cascades resulting in the determination of multipole mixing ratios delta(E2/M1) for 15 ..gamma.. transitions. The present results permitted a definite spin assignment of (7/2) for the 785 keV level and confirmation of several previous assignments to other levels in /sup 127/Te. The g factor of the 340 keV ((9/2)/sup -/) level has also been measured using the integral perturbed angular correlation method in the hyperfine magnetic field of a Te in Ni matrix. The results of the g factor as well as the mixing ratio for the 252 keV ((9/2)/sup -/..-->..(11/2)/sup -/) transition support the earlier interpretation of this state as an anomalous coupling state.

de Souza, M.O.M.D.; Saxena, R.N.

1985-02-01T23:59:59.000Z

396

Measurements of B to V(Gamma) Decays  

SciTech Connect (OSTI)

The standard model has been highly successful at describing current experimental data. However, extensions of the standard model predict particles that have masses at energy scales that are above the electroweak scale. The flavor-changing neutral current processes of the B meson are sensitive to the influences of these new physics contributions. These processes proceed through loop diagrams, thus allowing new physics to enter at the same order as the standard model. New physics may contribute to the enhancement or suppression of rate asymmetries or the decay rates of these processes. The transition B {yields} V{gamma} (V = K*(892), {rho}(770), {omega}(782), {phi}(1020)) represents radiative decays of the B meson that proceed through penguin processes. Hadronic uncertainties limit the theoretical accuracy of the prediction of the branching fractions. However, uncertainties, both theoretical and experimental, are much reduced when considering quantities involving ratios of branching fractions, such as CP or isospin asymmetries. The most dominant exclusive radiative b {yields} s transition is B {yields} K*{gamma}. We present the best measurements of the branching fractions, direct CP, and isospin asymmetries of B {yields} K*{gamma}. The analogous b {yields} d transitions are B {yields} {rho}{gamma} and B {yields} {omega}{gamma}, which are suppressed by a factor of |V{sub td}/V{sub ts}|{sup 2} {approx} 0.04 relative to B {yields} K*{gamma}. A measurement of the branching fractions and isospin asymmetry of B{sup +} {yields} {rho}{sup +}{gamma} and B{sup 0} {yields} {rho}{sup 0}{gamma}, as well as a search for B {yields} {omega}{gamma}, are also given. These measurements are combined to calculate the ratio of CKM matrix elements |V{sub td}/V{sub ts}|, which corresponds to the length of one side of the unitary triangle. Finally, we present a search for the penguin annihilation process B {yields}{phi}{gamma}. We use a sample of 383 million B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy B factory for the analysis of B {yields} K*{gamma}. We measure the branching fractions {Beta}(B{sup 0} {yields} K*{sup 0}{gamma}) = (4.47 {+-} 0.10 {+-} 0.16) x 10{sup -5} and {Beta}(B{sup +} {yields} K*{sup +}{gamma}) = (4.22 {+-} 0.14 {+-} 0.16) x 10{sup -5}. We measure the direct CP asymmetry to be -0.033 < {Alpha}{sub CP} (B {yields} K*{gamma}) < 0.028 and the isospin asymmetry to be 0.017 < {Delta}{sub 0-} < 0.116, where the limits are determined at the 90% C.L. and include both the statistical and systematic uncertainties. Using a sample of 347 million B{bar B} events, we measure the branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) = (1.10{sub -0.33}{sup +0.37} {+-} 0.09) x 10{sup -6} and {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) = (0.79{sub -0.20}{sup +0.22} {+-} 0.06) x 10{sup -6}, the isospin asymmetry {Delta} = -0.35 {+-} 0.27, and set a 90% C.L. upper limit {Beta}(B {yields} {omega}{gamma}) < 0.78 x 10{sup -6}. We also measure the isospin-averaged branching fraction {Beta}(B {yields} ({rho}/{omega}){gamma}) = (1.25{sub -0.24}{sup +0.25} {+-} 0.09) x 10{sup -6}, from which we determine |V{sub td}/V{sub ts}|= 0.200{sub -0.020}{sup +0.021} {+-} 0.015, where the first uncertainty is experimental and the second theoretical. Finally, a sample of 124 million B{bar B} events is used to set an upper limit of {Beta}(B {yields} {phi}{gamma}) < 8.5 x 10{sup -7} at the 90% C.L.

Yarritu, Aaron K.; /Stanford U., Phys. Dept.; ,

2010-09-02T23:59:59.000Z

397

NEW SOURCES OF RADIATION  

E-Print Network [OSTI]

Stanford Synchrotron Radiation Project Report No. 75/07.IBL 79M0733 Fig. 20. Radiation emission pattern by electronsWinick, Stanford Synchrotron Radiation Laboratory. Fig. 21.

Schimmerling, W.

2010-01-01T23:59:59.000Z

398

Radiation-induced angiosarcoma  

E-Print Network [OSTI]

1a Figure 1b Figure 1. Radiation-induced angiosarcoma in afollowing completion of radiation therapy. Figure 2a Figurecell histiocytosis after radiation for breast carcinoma: can

Anzalone, C Lane; Cohen, Philip R; Diwan, Abdul H; Prieto, Victor G

2013-01-01T23:59:59.000Z

399

Radiation Protection Act (Pennsylvania)  

Broader source: Energy.gov [DOE]

This Act combines the radiation safety provisions of The Atomic Energy Development and Radiation Control Act and the Environmental Radiation Protection Act, and empowers the Department of...

400

The emission of Gamma Ray Bursts as a test-bed for modified gravity  

E-Print Network [OSTI]

The extreme physical conditions of Gamma Ray Bursts can constitute a useful observational laboratory to test theories of gravity where very high curvature regimes are involved. Here we propose a sort of curvature engine capable, in principle, of explaining the huge energy emission of Gamma Ray Bursts. Specifically, we investigate the emission of radiation by charged particles non-minimally coupled to the gravitational background where higher order curvature invariants are present. The coupling gives rise to an additional force inducing a non-geodesics motion of particles. This fact allows a strong emission of radiation by gravitationally accelerated particles. As we will show with some specific model, the energy emission is of the same order of magnitude of that characterizing the Gamma Ray Burst physics. Alternatively, strong curvature regimes can be considered as a natural mechanism for the generation of highly energetic astrophysical events.

Capozziello, Salvatore

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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401

The emission of Gamma Ray Bursts as a test-bed for modified gravity  

E-Print Network [OSTI]

The extreme physical conditions of Gamma Ray Bursts can constitute a useful observational laboratory to test theories of gravity where very high curvature regimes are involved. Here we propose a sort of curvature engine capable, in principle, of explaining the huge energy emission of Gamma Ray Bursts. Specifically, we investigate the emission of radiation by charged particles non-minimally coupled to the gravitational background where higher order curvature invariants are present. The coupling gives rise to an additional force inducing a non-geodesics motion of particles. This fact allows a strong emission of radiation by gravitationally accelerated particles. As we will show with some specific model, the energy emission is of the same order of magnitude of that characterizing the Gamma Ray Burst physics. Alternatively, strong curvature regimes can be considered as a natural mechanism for the generation of highly energetic astrophysical events.

Salvatore Capozziello; Gaetano Lambiase

2015-04-15T23:59:59.000Z

402

Discovery of TeV Gamma-Ray Emission from the Cygnus Region of the Galaxy  

E-Print Network [OSTI]

The diffuse gamma radiation arising from the interaction of cosmic ray particles with matter and radiation in the Galaxy is one of the few probes available to study the origin of the cosmic rays. Milagro is a water Cherenkov detector that continuously views the entire overhead sky. The large field-of-view combined with the long observation time makes Milagro the most sensitive instrument available for the study of large, low surface brightness sources such as the diffuse gamma radiation arising from interactions of cosmic radiation with interstellar matter. In this paper we present spatial and flux measurements of TeV gamma-ray emission from the Cygnus Region. The TeV image shows at least one new source MGRO J2019+37 as well as correlations with the matter density in the region as would be expected from cosmic-ray proton interactions. However, the TeV gamma-ray flux as measured at ~12 TeV from the Cygnus region (after excluding MGRO J2019+37) exceeds that predicted from a conventional model of cosmic ray prod...

Abdo, A A; Berley, D; Blaufuss, E; Casanova, S; Chen, C; Coyne, D G; Delay, R S; Dingus, B L; Ellsworth, R W; Fleysher, L; Fleysher, R; González, M M; Goodman, J A; Hays, E; Hoffman, C M; Kolterman, B E; Kelley, L A; Lansdell, C P; Linnemann, J T; McEnery, J E; Mincer, A I; Moskalenko, I V; Némethy, P; Noyes, D; Ryan, J M; Samuelson, F W; Parkinson, P M S; Schneider, M; Shoup, A; Sinnis, G; Smith, A J; Strong, A W; Sullivan, G W; Vasileiou, V; Walker, G P; Williams, D A; Xu, X W; Yodh, G B

2006-01-01T23:59:59.000Z

403

High spatial resolution X-ray and gamma ray imaging system using diffraction crystals  

DOE Patents [OSTI]

A method and a device for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation are provided. The device comprises a plurality of arrays, with each array comprising a plurality of elements comprising a first collimator, a diffracting crystal, a second collimator, and a detector.

Smither, Robert K. (Hinsdale, IL)

2011-05-17T23:59:59.000Z

404

Gamma ray spectroscopic analysis of building materials used in Tiruvannamalai, Tamilnadu, India  

SciTech Connect (OSTI)

Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials in Tiruvannamalai, city, have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. All samples under investigation are within the recommended safety limit when used as building construction.

Ravisankar, R.; Vanasundari, K.; Suganya, M.; Chandrasekaran, A.; Raghu, Y.; Sivakumar, S.; Vijayagopal, P.; Meenakshisundaram, V. [Post Graduate and Research Department of Physics, Government Arts College, Tiruvannamalai-606603 (India); Department of Physics, Global Institute of Engineering and Technology, Vellore-632509, Tamilnadu (India); Department of Physics, Aarupadai Veedu Institute of Technology, Paiyanoor-603 104.Tamilnadu (India); Department of Physics, Arunai Engineering College, Tiruvannamalai-606603, Tamilnadu (India); Radiological Safety Division. Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2012-06-05T23:59:59.000Z

405

Matter Wave Radiation Leading to Matter Teleportation  

E-Print Network [OSTI]

The concept of matter wave radiation is put forward, and its equation is established for the first time. The formalism solution shows that the probability density is a function of displacement and time. A free particle and a two-level system are reinvestigated considering the effect of matter wave radiation. Three feasible experimental designs, especially a modified Stern-Gerlach setup, are proposed to verify the existence of matter wave radiation. Matter wave radiation effect in relativity has been formulated in only a raw formulae, which offers another explanation of Lamb shift. A possible mechanics of matter teleportation is predicted due to the effect of matter wave radiation.

Yong-Yi Huang

2015-02-12T23:59:59.000Z

406

Radiative Leptonic B Decays  

SciTech Connect (OSTI)

We present the results of a search for B{sup +} meson decays into {gamma}{ell}{sup +}{nu}{sub {ell}}, where {ell} = e,{mu}. We use a sample of 232 million B{bar B} meson pairs recorded at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II B factory. We measure a partial branching fraction {Delta}{beta} in a restricted region of phase space that reduces the effect of theoretical uncertainties, requiring the lepton energy to be in the range 1.875 and 2.850 GeV, the photon energy to be in the range 0.45 and 2.35 GeV, and the cosine of the angle between the lepton and photon momenta to be less than -0.36, with all quantities computed in the {Upsilon}(4S) center-of-mass frame. We find {Delta}{Beta}(B{sup +} {yields} {gamma}{ell}{sup +}{nu}{sub {ell}}) = (-0.3{sub 1.5}{sup +1.3}(statistical){sub -0.6}{sup +0.6}(systematic) {+-} 0.1(theoretical)) x 10{sup -6}, under the assumption of lepton universality. Interpreted as a 90% confidence-level Bayesian upper limit, the result corresponds to 1.7 x 10{sup -6} for a prior at in amplitude, and 2.3 x 10{sup -6} for a prior at in branching fraction.

Chen, Edward Tann; /Caltech; ,

2008-10-06T23:59:59.000Z

407

Neutron and Gamma Probe Application to Hanford Tank 241-SY-101  

SciTech Connect (OSTI)

A neutron (moisture-sensitive) and gamma (in-situ radiation) probe technique has been utilized at a number of Hanford radioactive waste tanks for many years. This technology has been adapted for use in tank 241-SY-101's two Multifunction Instrument Trees (MITs) which have a hollow dry-well center opening two inches (51 cm) in diameter. These probes provide scans starting within a few inches of the tank bottom and traversing up through the top of the tank revealing a variety of waste features as a function of tank elevation. These features have been correlated with void fraction data obtained independently from two other devices, the Retained Gas Sampler (RGS) and the Void Fraction Instrument (VFI). The MIT probes offer the advantage of nearly continuous count-rate versus elevation scans and they can be operated significantly more often and at lower cost than temperature probes or the RGS or VFI devices while providing better depth resolution. The waste level in tank 241-SY-101 had been rising at higher rates than expected during 1998 and early 1999 indicating an increasing amount of trapped gas in the waste. The use of the MIT probes has assisted in evaluating changes in crust thickness and level and also in estimating relative changes in gas stored in the crust. This information is important in assuring that the tank remains in a safe configuration and will support safe waste transfer when those operations take place.

CANNON, N.S.

2000-02-01T23:59:59.000Z

408

Gamma-ray bursts, axion emission and string theory dilaton  

E-Print Network [OSTI]

The emission of axions from supernovae is an interesting possibility to account for the Gamma-Ray Bursts provided their energy can be effectively converted into electromagnetic energy elsewhere. The connection between supernova and gamma-ray bursts has been recently confirmed by the observed correlation between the burst of April 25, 1998 and the supernova SN1998bw. We argue that the axion convertion into photons can be more efficient if one considers the coupling between an intermediate scale axion and the string theory dilaton along with the inclusion of string loops. We also discuss the way dilaton dynamics may allow for a more effective energy exchange with electromagnetic radiation in the expansion process of fireballs.

O. Bertolami

1999-01-14T23:59:59.000Z

409

Gamma Ray Mirrors for Direct Measurement of Spent Nuclear Fuel  

SciTech Connect (OSTI)

Direct measurement of the amount of Pu and U in spent nuclear fuel represents a challenge for the safeguards community. Ideally, the characteristic gamma-ray emission lines from different isotopes provide an observable suitable for this task. However, these lines are generally lost in the fierce flux of radiation emitted by the fuel. The rates are so high that detector dead times limit measurements to only very small solid angles of the fuel. Only through the use of carefully designed view ports and long dwell times are such measurements possible. Recent advances in multilayer grazing-incidence gamma-ray optics provide one possible means of overcoming this difficulty. With a proper optical and coating design, such optics can serve as a notch filter, passing only narrow regions of the overall spectrum to a fully shielded detector that does not view the spent fuel directly. We report on the design of a mirror system and a number of experimental measurements.

Pivovaroff, Dr. Michael J. [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Ziock, Klaus-Peter [ORNL] [ORNL; Harrison, Mark J [ORNL] [ORNL; Soufli, Regina [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL)

2014-01-01T23:59:59.000Z

410

Overview of the gamma reaction history diagnostic for the national ignition facility (NIF)  

SciTech Connect (OSTI)

The National Ignition Facility (NIF) has a need for measuring gamma radiation as part of a nuclear diagnostic program. A new gamma-detection diagnostic uses 900 off-axis parabolic mirrors to rel ay Cherenkov light from a volume of pressurized gas. This non imaging optical system has the high-speed detector placed at a stop position with the Cherenkov light delayed until after the prompt gammas have passed through the detector. Because of the wavelength range (250 to 700 nm), the optical element surface finish was a key design constraint. A cluster of four channels (each set to a different gas pressure) will collect the time histories for different energy ranges of gammas.

Kim, Yong Ho [Los Alamos National Laboratory; Evans, Scott C [Los Alamos National Laboratory; Herrmann, Hans W [Los Alamos National Laboratory; Mack, Joseph M [Los Alamos National Laboratory; Young, Carl S [Los Alamos National Laboratory; Malone, Robert M [Los Alamos National Laboratory; Cox, Brian C [Los Alamos National Laboratory; Frogget, Brent C [Los Alamos National Laboratory; Kaufman, Morris I [Los Alamos National Laboratory; Tunnell, Thomas W [Los Alamos National Laboratory; Tibbitts, Aric [Los Alamos National Laboratory; Palagi, Martin J [NST/LAS VEGAS; Stoeffl, Wolfgang [LLNL

2010-01-01T23:59:59.000Z

411

Digital discrimination of neutrons and gamma-rays in organic scintillation detectors using moment analysis  

SciTech Connect (OSTI)

Digital discrimination of neutron and gamma-ray events in an organic scintillator has been investigated by moment analysis. Signals induced by an americium-beryllium (Am/Be) isotropic neutron source in a stilbene crystal detector have been sampled with a flash analogue-to-digital converter (ADC) of 1 GSamples/s sampling rate and 10-bit vertical resolution. Neutrons and gamma-rays have been successfully discriminated with a threshold corresponding to gamma-ray energy about 217 keV. Moment analysis has also been verified against the results assessed by a time-of-flight (TOF) measurement. It is shown that the classification of neutrons and gamma-rays afforded by moment analysis is consistent with that achieved by digital TOF measurement. This method has been applied to analyze the data acquired from the stilbene crystal detector in mixed radiation field of the HL-2A tokamak deuterium plasma discharges and the results are described.

Xie Xufei; Zhang Xing; Yuan Xi; Chen Jinxiang; Li Xiangqing; Zhang Guohui; Fan Tieshuan [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing (China); Yuan Guoliang; Yang Jinwei; Yang Qingwei [Southwestern Institute of Physics, Chengdu (China)

2012-09-15T23:59:59.000Z

412

Atomistic simulations of radiation damage in amorphous metal alloys  

E-Print Network [OSTI]

While numerous fundamental studies have characterized the atomic-level radiation response mechanisms in irradiated crystalline alloys, comparatively little is known regarding the mechanisms of radiation damage in amorphous ...

Baumer, Richard E. (Richard Edward)

2013-01-01T23:59:59.000Z

413

ON THE RECENTLY DISCOVERED CORRELATIONS BETWEEN GAMMA-RAY AND X-RAY PROPERTIES OF GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

Recently, many correlations between the prompt {gamma}-ray emission properties and the X-ray afterglow properties of gamma-ray bursts (GRBs) have been inferred from a comprehensive analysis of the X-ray light curves of more than 650 GRBs measured with the Swift X-Ray Telescope (Swift/XRT) during the years 2004-2010. We show that these correlations are predicted by the cannonball (CB) model of GRBs. They result from the dependence of GRB observables on the bulk motion Lorentz factor and viewing angle of the jet of highly relativistic plasmoids (CBs) that produces the observed radiations by interaction with the medium through which it propagates. Moreover, despite their different physical origins, long GRBs (LGRBs) and short-hard bursts (SHBs) in the CB model share similar kinematic correlations, which can be combined into triple correlations satisfied by both LGRBs and SHBs.

Dado, Shlomo; Dar, Arnon [Physics Department, Technion, Haifa 32000 (Israel)

2013-09-20T23:59:59.000Z

414

Exclusive search for Higgs boson to gamma-gamma decay via vector boson fusion production mechanism .  

E-Print Network [OSTI]

??We perform an exclusive search for the Higgs boson to gamma-gamma decay via vector boson fusion. We utilize the characteristic features of vector boson fusion,… (more)

Rankin, Dylan Sheldon

2012-01-01T23:59:59.000Z

415

Radiation exposure in X-ray-based imaging techniques used in osteoporosis  

E-Print Network [OSTI]

to low levels of ionizing radiation: BEIR VII Phase 2. TheBlake G, Genant HK (1999) Radiation exposure in bone mineralGuglielmi Thomas M. Link Radiation exposure in X-ray-based

Damilakis, John; Adams, Judith E.; Guglielmi, Giuseppe; Link, Thomas M.

2010-01-01T23:59:59.000Z

416

FY2008 Report on GADRAS Radiation Transport Methods.  

SciTech Connect (OSTI)

The primary function of the Gamma Detector Response and Analysis Software (GADRAS) is the solution of inverse radiation transport problems, by which the con-figuration of an unknown radiation source is inferred from one or more measured radia-tion signatures. GADRAS was originally developed for the analysis of gamma spec-trometry measurements. During fiscal years 2007 and 2008, GADRAS was augmented to implement the simultaneous analysis of neutron multiplicity measurements. This report describes the radiation transport methods developed to implement this new capability. This work was performed at the direction of the National Nuclear Security Administration's Office of Nonproliferation Research and Development. It was executed as an element of the Proliferation Detection Program's Simulation, Algorithm, and Modeling element. Acronyms BNL Brookhaven National Laboratory CSD Continuous Slowing-Down DU depleted uranium ENSDF Evaluated Nuclear Structure Data Files GADRAS Gamma Detector Response and Analysis Software HEU highly enriched uranium LANL Los Alamos National Laboratory LLNL Lawrence Livermore National Laboratory NA-22 Office of Nonproliferation Research and Development NNDC National Nuclear Data Center NNSA National Nuclear Security Administration ODE ordinary differential equation ONEDANT One-dimensional diffusion accelerated neutral particle transport ORNL Oak Ridge National Laboratory PARTISN Parallel time-dependent SN PDP Proliferation Detection Program RADSAT Radiation Scenario Analysis Toolkit RSICC Radiation Safety Information Computational Center SAM Simulation, Algorithms, and Modeling SNL Sandia National Laboratories SNM special nuclear material ToRI Table of Radioactive Isotopes URI uniform resource identifier XML Extensible Markup Language

Mattingly, John K.; Mitchell, Dean James; Harding, Lee; Varley, Eric S.; Hilton, Nathan R. [Sandia National Laboratories, Livermore, CA

2008-10-01T23:59:59.000Z

417

A Topological Structure in the Set of Classical Free Radiation Electromagnetic Fields  

E-Print Network [OSTI]

The aim of this work is to proceed with the development of a model of topological electromagnetism in empty space, proposed by one of us some time ago and based on the existence of a topological structure associated with the radiation fields in standard Maxwell's theory. This structure consists in pairs of complex scalar fields, say $\\phi$ and $\\theta$, that can be interpreted as maps $\\phi,\\theta: S^3\\mapsto S^2$, the level lines of which are orthogonal to one another, where $S^3$ is the compactified physical 3-space $R^3$, with only one point at infinity, and $S^2$ is the 2-sphere identified with the complete complex plane. These maps were discovered and studied in 1931 by the German mathematician H. Hopf, who showed that the set of all of them can be ordered in homotopy classes, labeled by the so called Hopf index, equal to $\\gamma=\\pm 1,\\,\\pm 2,\\,\\cdots ,\\, \\pm k,...$ but without $\\gamma=0$. In the model presented here and at the level of the scalars $\\phi$ and $\\theta$, the equations of motion are highly nonlinear; however there is a transformation of variables that converts exactly these equations (not by truncation!) into the linear Maxwell's ones for the magnetic and electric fields $\\B$ and $\\E$.

A. F. Ranada; A. Tiemblo

2014-07-29T23:59:59.000Z

418

Graphite Gamma Scan Results  

SciTech Connect (OSTI)

This report documents the measurement and data analysis of the radio isotopic content for a series of graphite specimens irradiated in the first Advanced Graphite Creep (AGC) experiment, AGC-1. This is the first of a series of six capsules planned as part of the AGC experiment to fully characterize the neutron irradiation effects and radiation creep behavior of current nuclear graphites. The AGC-1 capsule was irradiated in the Advanced Test Reactor (ATR) at INL at approximately 700 degrees C and to a peak dose of 7 dpa (displacements per atom). Details of the irradiation conditions and other characterization measurements performed on specimens in the AGC-1 capsule can be found in “AGC-1 Specimen Post Irradiation Data Report” ORNL/TM 2013/242. Two specimens from six different graphite types are analyzed here. Each specimen is 12.7 mm in diameter by 25.4 mm long. The isotope with the highest activity was 60Co. Graphite type NBG-18 had the highest content of 60Co with an activity of 142.89 µCi at a measurement distance of 47 cm.

Mark W. Drigert

2014-04-01T23:59:59.000Z

419

GAMMA DETECTOR RESPONSE/SOIL CONCENTRATION CORRELATION STUDY AT THE AAR MANUFACTURING, INC. SITE, LIVONIA, MICHIGAN  

SciTech Connect (OSTI)

At the NRC?s request, ORAU conducted surveys of the AAR Manufacturing site during the period of September 25 through September 27, 2012. The survey activities included walkover surveys and sampling activities. Once the survey team was onsite, the NRC personnel decided to forgo survey activities in the ?New Addition? and the pickling area. Areas of the planned study boundary were inaccessible due to overgrowth/large pieces of concrete covering the soil surface; therefore, the study boundary was redefined. Gamma walkover scans of the site boundary and ?front yard? identified multiple areas of elevated gamma radiation. As a result, two judgmental samples were collected. Sample results were above thorium background levels The answer to the PSQ relating to the relationship between thorium concentration in soil and NaI instrument response is ?Yes.? NaI instrument response can be used as a predictor of Th-232 concentration in the 0 to 1 m layer. An R2 value of 0.79 was determined for the surface soil relationship, thus satisfying the DQOs. Moreover, the regression was cross-checked by comparing the predicted Th-232 soil core concentration to the average Th-232 concentration (Section 5.3.2). Based on the cross-check, the regression equation provides a reasonable estimate for the Th-232 concentration at the judgmental locations. Consideration must be given when applying this equation to other soil areas of the site. If the contamination was heterogeneously distributed, and not distributed in a discrete layer as it was in the study area, then using the regression equation to predict Th-232 concentration would not be applicable.

ALTIC, NICK A

2013-03-22T23:59:59.000Z

420

Gamma-ray bursts and terrestrial planetary atmospheres  

E-Print Network [OSTI]

We describe results of modeling the effects of gamma-ray bursts (GRBs) within a few kiloparsecs of an Earth-like planet. A primary effect is generation of nitrogen oxide compounds which deplete ozone. Ozone depletion leads to an increase in solar UVB radiation at the surface, enhancing DNA damage, particularly in marine microorganisms such as phytoplankton. In addition, we expect increased atmospheric opacity due to buildup of nitrogen dioxide produced by the burst and enhanced precipitation of nitric acid. We review here previous work on this subject and discuss recent developments.

Thomas, B C; Thomas, Brian C.; Melott, Adrian L.

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

Gamma-ray free-electron lasers: Quantum fluid model  

E-Print Network [OSTI]

A quantum fluid model is used to describe the interacion of a nondegenerate cold relativistic electron beam with an intense optical wiggler taking into account the beam space-charge potential and photon recoil effect. A nonlinear set of coupled equations are obtained and solved numerically. The numerical results shows that in the limit of plasma wave-breaking an ultra-high power radiation pulse are emitted at the$\\gamma$-ray wavelength range which can reach an output intensity near the Schwinger limit depending of the values of the FEL parameters such as detuning and input signal initial phase at the entrance of the interaction region.

Silva, H M

2014-01-01T23:59:59.000Z

422

Tritium monitor with improved gamma-ray discrimination  

DOE Patents [OSTI]

Apparatus and method are presented for selective measurement of tritium oxide in an environment which may include other radioactive components and gamma radiation, the measurement including the selective separation of tritium oxide from a sample gas through a membrane into a counting gas, the generation of electrical pulses individually representative by rise times of tritium oxide and other radioactivity in the counting gas, separation of the pulses by rise times, and counting of those pulses representative of tritium oxide. The invention further includes the separate measurement of any tritium in the sample gas by oxidizing the tritium to tritium oxide and carrying out a second separation and analysis procedure as described above.

Cox, S.A.; Bennett, E.F.; Yule, T.J.

1982-10-21T23:59:59.000Z

423

Tritium monitor with improved gamma-ray discrimination  

DOE Patents [OSTI]

Apparatus and method for selective measurement of tritium oxide in an environment which may include other radioactive components and gamma radiation, the measurement including the selective separation of tritium oxide from a sample gas through a membrane into a counting gas, the generation of electrical pulses individually representative by rise times of tritium oxide and other radioactivity in the counting gas, separation of the pulses by rise times, and counting of those pulses representative of tritium oxide. The invention further includes the separate measurement of any tritium in the sample gas by oxidizing the tritium to tritium oxide and carrying out a second separation and analysis procedure as described above.

Cox, Samson A. (Downers Grove, IL); Bennett, Edgar F. (Downers Grove, IL); Yule, Thomas J. (West Chicago, IL)

1985-01-01T23:59:59.000Z

424

Gamma-Ray Bursts and Dark Energy - Dark Matter interaction  

E-Print Network [OSTI]

In this work Gamma Ray Burst (GRB) data is used to place constraints on a putative coupling between dark energy and dark matter. Type Ia supernovae (SNe Ia) constraints from the Sloan Digital Sky Survey II (SDSS-II) first-year results, the cosmic microwave background radiation (CMBR) shift parameter from WMAP seven year results and the baryon acoustic oscillation (BAO) peak from the Sloan Digital Sky Survey (SDSS) are also discussed. The prospects for the field are assessed, as more GRB events become available.

T. Barreiro; O. Bertolami; P. Torres

2010-12-14T23:59:59.000Z

425

Day-Scale Variability of 3C 279 and Searches for Correlations in Gamma-Ray, X-Ray, and Optical Bands  

E-Print Network [OSTI]

Light curves of 3C 279 are presented in optical (R-band), X-rays (RXTE/PCA), and gamma rays (CGRO/EGRET) for 1999 Jan-Feb and 2000 Jan-Mar. During both of those epochs the gamma-ray levels were high, and all three observed bands demonstrated substantial variation, on time scales as short as one day. Correlation analyses provided no consistent pattern, although a rather significant optical/gamma-ray correlation was seen in 1999, with a gamma-ray lag of ~2.5 days, and there are other suggestions of correlations in the light curves. For comparison, correlation analysis is also presented for the gamma-ray and X-ray light curves during the large gamma ray flare in 1996 Feb and the two gamma-bright weeks leading up to it; the correlation at that time was strong, with a gamma-ray/X-ray offset of no more than 1 day.

R. C. Hartman; M. Villata; T. J. Balonek; D. L. Bertsch; H. Bock; M. Boettcher; M. T. Carini; W. Collmar; G. De Francesco; E. C. Ferrara; J. Heidt; G. Kanbach; S. Katajainen; M. Koskimies; O. M. Kurtanidze; L. Lanteri; A. Lawson; Y. C. Lin; A. P. Marscher; J. P. McFarland; I. M. McHardy; H. R. Miller; M. Nikolashvili; K. Nilsson; J. C. Noble; G. Nucciarelli; L. Ostorero; T. Pursimo; C. M. Raiteri; R. Rekola; T. Savolainen; A. Sillanpaa; A. Smale; G. Sobrito; L. O. Takalo; D. J. Thompson; G. Tosti; S. J. Wagner; J. W. Wilson

2001-05-15T23:59:59.000Z

426

A Study of Radiative Bottomonium Transitions using Converted Photons  

SciTech Connect (OSTI)

The authors use (111 {+-} 1) million {Upsilon}(3S) and (89 {+-} 1) million {Upsilon}(2S) events recorded by the BABAR detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions betwen bottomonium states using photons that have been converted to e{sup +}e{sup -} pairs by the detector material. They observe {Upsilon}(3S) {yields} {gamma}{chi}{sub b0,2}(1P) decay, make precise measurements of the branching fractions for {chi}{sub b1,2}(1P, 2P) {yields} {gamma}{Upsilon}(1S) and {chi}{sub b1,2}(2P) {yields} {gamma}{Upsilon}(2S) decays, and search for radiative decay to the {eta}{sub b}(1S) and {eta}{sub b}(2S) states.

Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; /INFN, Bari /Bari U.; Milanes, D.A.; /INFN, Bari; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /UC, Berkeley; Koch, H.; Schroeder, T.; /Ruhr U., Bochum; Asgeirsson, D.J.; Hearty, C.; /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Paris U., VI-VII /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

2011-08-15T23:59:59.000Z

427

Neutrinos from Gamma Ray Bursts  

E-Print Network [OSTI]

We show that the detection of neutrinos from a typical gamma ray burst requires a kilometer-scale detector. We argue that large bursts should be visible with the neutrino telescopes under construction. We emphasize the 3 techniques by which neutrino telescopes can perform this search: by triggering on i) bursts of muons from muon neutrinos, ii) muons from air cascades initiated by high energy gamma rays and iii) showers made by relatively low energy ($\\simeq 100\\,\\mev$) electron neutrinos. Timing of neutrino-photon coincidences may yield a measurement of the neutrino mass to order $10^{-5}$~eV, an interesting range in light of the solar neutrino anomaly.

F. Halzen; G. Jaczko

1996-02-07T23:59:59.000Z

428

Gamma source for active interrogation  

DOE Patents [OSTI]

A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

Leung, Ka-Ngo; Lou, Tak Pui; Barletta, William A.

2012-10-02T23:59:59.000Z

429

sin 2 beta + gamma Measurements  

SciTech Connect (OSTI)

I report on the most recent measurements done to constrain sin(2{beta}+{gamma}) with neutral B mesons. Direct measurements of 2{beta} + {gamma} will provide a precise test of the standard model predictions with higher statistics. Present constraints come from studies of B {yields} D{sup (*){+-}}{pi}{sup {-+}}/{rho}{sup {-+}} decays done by BABAR and Belle collaborations with full and inclusive techniques to reconstruct B mesons. B {yields} D{sup 0(*)}K{sup 0} decays are also very promising but statistics are too low to give any constraint at the moment.

Therin, G; /Paris U., VI-VII

2005-06-24T23:59:59.000Z

430

Gamma-ray Imaging Methods  

SciTech Connect (OSTI)

In this document we discuss specific implementations for gamma-ray imaging instruments including the principle of operation and describe systems which have been built and demonstrated as well as systems currently under development. There are several fundamentally different technologies each with specific operational requirements and performance trade offs. We provide an overview of the different gamma-ray imaging techniques and briefly discuss challenges and limitations associated with each modality (in the appendix we give detailed descriptions of specific implementations for many of these technologies). In Section 3 we summarize the performance and operational aspects in tabular form as an aid for comparing technologies and mapping technologies to potential applications.

Vetter, K; Mihailescu, L; Nelson, K; Valentine, J; Wright, D

2006-10-05T23:59:59.000Z

431

High energy Gamma-Ray Bursts as a result of the collapse and total annihilation of neutralino clumps  

E-Print Network [OSTI]

Rare astrophysical events - cosmological gamma-ray bursts with energies over GeV - are considered as an origin of information about some SUSY parameters. The model of generation of the powerful gamma-ray bursts is proposed. According to this model the gamma-ray burst represents as a result of the collapse and the total annihilation of the neutralino clump. About 80 % of the clump mass radiates during about 100 second at the final stage of annihilation. The annihilation spectrum and its characteristic energies are calculated in the framework of Split Higgsino model.

R. S. Pasechnik; V. A. Beylin; V. I. Kuksa; G. M. Vereshkov

2006-02-20T23:59:59.000Z

432

Higgs boson decays into {\\gamma}{\\gamma} and Z{\\gamma} in the MSSM and BLSSM  

E-Print Network [OSTI]

We calculate Higgs decay rates into {\\gamma}{\\gamma} and Z{\\gamma} in the Minimal Supersymmetric Standard Model (MSSM) and (B-L) Supersymmetric Standard Model (BLSSM) by allowing for contributions from light staus and charginos. We show that sizable departures are possible from the SM predictions for the 125 GeV state and that they are testable during run 2 at the Large Hadron Collider. Furthermore, we illustrate how a second light scalar Higgs signal in either or both these decay modes can be accessed at the CERN machine rather promptly within the BLSSM, a possibility instead precluded to the MSSM owing to the much larger mass of its heavy scalar state.

Hammad, A; Moretti, S

2015-01-01T23:59:59.000Z

433

PUBLISHED VERSION Gamma ray spectrometer for ITER  

E-Print Network [OSTI]

Ray Scintillation Spectrometer Rev. Sci. Instrum. 24, 1096 (1953); 10.1063/1.1770609 An Automatic Recording Gamma for the spectrometer is presented. Keywords: tokamak, DT plasma, alpha- particles, diagnostics, gamma- spectrometry

434

The Diverse Environments of Gamma-Ray Bursts  

E-Print Network [OSTI]

Galaxies of Dark Gamma-Ray Bursts: Observational Constraintsof a Very Bright Gamma- Ray Burst in a Galactic Halo 3.11.3 Gamma-Ray Burst Classi?cation . . . . . . 1.4 Gamma-Ray

Perley, Daniel Alan

2011-01-01T23:59:59.000Z

435

Beta-delayed gamma spectroscopy of neutron rich 27,28,29Na  

SciTech Connect (OSTI)

The low-energy level structure of the exotic Na isotopes {sup 27,28,29}Na has been investigated through {beta}-delayed {gamma} spectroscopy. Detailed level structure of {sup 28,29}Na has been obtained through {beta}{gamma} and {beta}{gamma}{gamma} coincidence measurements. The low-lying levels populated in {sup 27}Na by {beta} decay were found to corroborate well with the in-beam data from the literature. Half-lives of the parent nuclides, {sup 27,28,29}Ne, were measured using {beta} fragment as well as fragment {beta}{gamma} coincidences and compared to previous measurements. The {beta}-delayed one- and two-neutron emission branching probabilities have been obtained from the {gamma} activities of the grand daughter nuclei. A comparison of the level schemes and the {beta}-decay branching ratios is made with shell-model predictions, both with and without intruder configurations, to understand the transition from normal-dominant to intruder-dominant excitations in these neutron-rich nuclei approaching the island of inversion.

Tripathi, V.; Tabor, S.L.; Hoffman, C.R.; Wiedeking, M.; Volya,A.; Mantica, P.F.; Davies, A.D.; Liddick, S.N.; Mueller, W.F.; Stolz, A.; Tomlin, B.E.

2006-05-04T23:59:59.000Z

436

{beta}-delayed {gamma} spectroscopy of neutron rich {sup 27,28,29}Na  

SciTech Connect (OSTI)

The low-energy level structure of the exotic Na isotopes {sup 27,28,29}Na has been investigated through {beta}-delayed {gamma} spectroscopy. Detailed level structure of {sup 28,29}Na has been obtained through {beta}{gamma} and {beta}{gamma}{gamma} coincidence measurements. The low-lying levels populated in {sup 27}Na by {beta} decay were found to corroborate well with the in-beam data from the literature. Half-lives of the parent nuclides, {sup 27,28,29}Ne, were measured using {beta} fragment as well as fragment {beta}{gamma} coincidences and compared to previous measurements. The {beta}-delayed one- and two-neutron emission branching probabilities have been obtained from the {gamma} activities of the grand daughter nuclei. A comparison of the level schemes and the {beta}-decay branching ratios is made with shell-model predictions, both with and without intruder configurations, to understand the transition from normal-dominant to intruder-dominant excitations in these neutron-rich nuclei approaching the island of inversion.

Tripathi, Vandana; Tabor, S.L.; Hoffman, C.R.; Wiedeking, M.; Volya, A.; Otsuka, T.; Utsuno, Y. [Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Tokyo 113-0033 (Japan) and RIKEN, Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Advanced Science Research Centre, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Mantica, P.F.; Liddick, S.N.; Tomlin, B.E. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 (United States); Davies, A.D. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Mueller, W.F.; Stolz, A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

2006-05-15T23:59:59.000Z

437

New Remote Method for Estimation of Contamination Levels of Reactor Equipment - 13175  

SciTech Connect (OSTI)

Projects for decommissioning of shutdown reactors and reactor facilities carried out in several countries, including Russia. In the National Research Centre 'Kurchatov Institute' decontamination and decommissioning of the research reactor MR (Material Testing Reactor) has been initiated. The research reactor MR has a long history and consists of nine loop facilities for experiments with different kinds of fuel. During the operation of main and auxiliary equipment of reactors it was subjected to strong radioactive contamination. The character of this contamination requires individual strategies for the decontamination work. This requires information about the character of the distribution of radioactive contamination of equipment in the premises. A detailed radiation survey of these premises using standard dosimetric equipment is almost impossible because of high levels of radiation and high-density of the equipment that does not allow identifying the most active fragments using standard tools of measurement. The problem can be solved using the method of remote measurements of distribution of radioactivity with help of the collimated gamma-ray detectors. For radiation surveys of the premises of loop installations remotely operated spectrometric collimated system was used [1, 2, 3]. As a result of the work, maps of the distribution of activity and dose rate for surveyed premises were plotted and superimposed on its photo. The new results of measurements in different areas of the reactor and at its loop installations, with emphasis on the radioactive survey of highly-contaminated samples, are presented. (authors)

Danilovich, Alexey; Ivanov, Oleg; Potapov, Victor; Semenov, Sergey; Semin, Ilya; Smirnov, Sergey; Stepanov, Vyacheslav; Volkovich, Anatoly [National Research Centre 'Kurchatov Institute', Moscow (Russian Federation)] [National Research Centre 'Kurchatov Institute', Moscow (Russian Federation)

2013-07-01T23:59:59.000Z

438

Light Curves of Swift Gamma Ray Bursts  

E-Print Network [OSTI]

Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short - long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars.

Paolo Cea

2006-09-22T23:59:59.000Z

439

Pulsed Gamma-Ray-Burst Afterglows  

E-Print Network [OSTI]

provides a candidate for the central engine of the gamma-ray burst (GRB) mechanism, both long and short

J. Middleditch

2009-01-01T23:59:59.000Z

440

Capture Gamma-Ray Libraries for Nuclear Applications  

SciTech Connect (OSTI)

The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. This can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research Project. EGAF has been used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90percent of all the decay energy an is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. We use CASINO, a version of DICEBOX that is modified for this purpose. This can be used to simulate the neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modelling of unknown assemblies.

Sleaford, B.W.; Firestone, Richard B.; Summers, N.; Escher, J.; Hurst, A.; Krticka, M.; Basunia, S.; Molnar, G.; Belgya, T.; Revay, Z.; Choi, H.D.

2010-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma radiation levels" 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

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

E-Print Network [OSTI]

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

Tomonori Totani

1998-11-25T23:59:59.000Z

442

E-Print Network 3.0 - angular gamma-gamma perturbada Sample Search...  

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

Page: << < 1 2 3 4 5 > >> 1 Interesting Interesting Summary: 5 10 15 20 25 (4S) Dataset: ffl 3.3 M B B ffl 4.8 M c c ffl 3.9 M + Gamma Gamma GammaGamma... (...

443

Error Rate Performance of Coded Free-Space Optical Links over Gamma-Gamma Turbulence Channels  

E-Print Network [OSTI]

Error Rate Performance of Coded Free-Space Optical Links over Gamma-Gamma Turbulence Channels Murat be used over free-space optical (FSO) links to mitigate turbulence-induced fading. In this paper, we channels, considering the recently introduced gamma-gamma turbulence model. We derive a pairwise error

Li, Tiffany Jing

444

The Universe Viewed in Gamma-Rays 1 Properties of Gamma-ray Bursts Localized by  

E-Print Network [OSTI]

The Universe Viewed in Gamma-Rays 1 Properties of Gamma-ray Bursts Localized by the HETE-2 and localize Gamma-ray bursts (GRBs) in wide field of view. HETE-2 have been localized about 20 GRBs per year hours after the burst. 1. The High Energy Transient Explorer 2 Gamma-ray burst (GRB) is the most

Enomoto, Ryoji

445

Very High Energy gamma-ray observations of Mrk 501 using TACTIC imaging gamma-ray telescope during 2005-06  

E-Print Network [OSTI]

In this paper we report on the Markarian 501 results obtained during our TeV $\\gamma$-ray observations from March 11 to May 12, 2005 and February 28 to May 7, 2006 for 112.5 hours with the TACTIC $\\gamma$-ray telescope. During 2005 observations for 45.7 hours, the source was found to be in a low state and we have placed an upper limit of 4.62 $\\times$ 10$^{-12}$ photons cm$^{-2}$ s$^{-1}$ at 3$\\sigma$ level on the integrated TeV $\\gamma$-ray flux above 1 TeV from the source direction. However, during the 2006 observations for 66.8h, detailed data analysis revealed the presence of a TeV $\\gamma$-ray signal from the source with a statistical significance of 7.5$\\sigma$ above $E_{\\gamma}\\geq$ 1 TeV. The time averaged differential energy spectrum of the source in the energy range 1-11 TeV is found to match well with the power law function of the form ($d\\Phi/dE=f_0 E^{-\\Gamma}$) with $f_0=(1.66\\pm0.52)\\times 10^{-11}cm^{-2}s^{-1}TeV^{-1}$ and $\\Gamma=2.80\\pm0.27$.

Godambe, S V; Chandra, P; Yadav, K K; Tickoo, A K; Venugopal, K; Bhatt, N; Bhattacharya, S; Chanchalani, K; Dhar, V K; Goyal, H C; Kaul, R K; Kothari, M; Kotwal, S; Koul, M K; Koul, R; Sahaynathan, B S; Sharma, M; Thoudam, S

2008-01-01T23:59:59.000Z

446

Adaptable radiation monitoring system and method  

DOE Patents [OSTI]

A portable radioactive-material detection system capable of detecting radioactive sources moving at high speeds. The system has at least one radiation detector capable of detecting gamma-radiation and coupled to an MCA capable of collecting spectral data in very small time bins of less than about 150 msec. A computer processor is connected to the MCA for determining from the spectral data if a triggering event has occurred. Spectral data is stored on a data storage device, and a power source supplies power to the detection system. Various configurations of the detection system may be adaptably arranged for various radiation detection scenarios. In a preferred embodiment, the computer processor operates as a server which receives spectral data from other networked detection systems, and communicates the collected data to a central data reporting system.

Archer, Daniel E. (Livermore, CA); Beauchamp, Brock R. (San Ramon, CA); Mauger, G. Joseph (Livermore, CA); Nelson, Karl E. (Livermore, CA); Mercer, Michael B. (Manteca, CA); Pletcher, David C. (Sacramento, CA); Riot, Vincent J. (Berkeley, CA); Schek, James L. (Tracy, CA); Knapp, David A. (Livermore, CA)

2006-06-20T23:59:59.000Z

447

Multifrequency Observations of Gamma-Ray Burst  

E-Print Network [OSTI]

Neither a flaring nor a quiescent counterpart to a gamma-ray burst has yet been convincingly identified at any wavelength region. The present status of the search for counterparts of classical gamma-ray bursts is given. Particular emphasis is put on the search for flaring counterparts, i.e. emission during or shortly after the gamma-ray emission.

J. Greiner

1995-10-04T23:59:59.000Z

448

High-Energy Cosmology: gamma rays and neutrinos from beyond the galaxy  

E-Print Network [OSTI]

Our knowledge of the high-energy universe is undergoing a period of rapid change as new astronomical detectors of high-energy radiation start to operate at their design sensitivities. Now is a boomtime for high-energy astrophysics, with new discoveries from Swift and HESS, results from MAGIC and VERITAS starting to be reported, the upcoming launches of the gamma-ray space telescopes GLAST and AGILE, and anticipated data releases from IceCube and Auger. A formalism for calculating statistical properties of cosmological gamma-ray sources is presented. Application is made to model calculations of the statistical distributions of gamma-ray and neutrino emission from (i) beamed sources, specifically, long-duration GRBs, blazars, and extagalactic microquasars, and (ii) unbeamed sources, including normal galaxies, starburst galaxies and clusters. Expressions for the integrated intensities of faint beamed and unbeamed high-energy radiation sources are also derived. A toy model for the background intensity of radiation from dark-matter annihilation taking place in the early universe is constructed. Estimates for the gamma-ray fluxes of local group galaxies, starburst, and infrared luminous galaxies are briefly reviewed. Because the brightest extragalactic gamma-ray sources are flaring sourc