WorldWideScience

Sample records for bremsstrahlung probing nuclear

  1. Thermal Bremsstrahlung probing nuclear multifragmentation in nucleus-nucleus collisions around the Fermi energy

    International Nuclear Information System (INIS)

    D'Enterria, D.G.

    2000-05-01

    The thermodynamical properties of nuclear matter at moderate temperatures and densities, in the vicinity of the predicted nuclear liquid-gas phase transition, are studied using as experimental probe the hard-photons (E γ > 30 MeV) emitted in nucleus-nucleus collisions. Photon and charged-particle production in four different heavy-ion reactions (Ar 36 + Au 197 , Ag 107 , Ni 58 , C 12 at 60 A*MeV) is measured exclusively and inclusively coupling the TAPS photon spectrometer with two charged-particle and intermediate-mass-fragment detectors covering nearly 4π. We confirm that Bremsstrahlung emission in first-chance (off-equilibrium) proton-neutron collisions (pnγ) is the dominant origin of hard photons. We also firmly establish the existence of a thermal radiation component emitted in second-chance proton-neutron collisions. This thermal Bremsstrahlung emission takes place in semi-central and central nucleus-nucleus reactions involving heavy targets. We exploit this observation i) to demonstrate that thermal equilibrium is reached during the reaction, ii) to establish a new thermometer of nuclear matter based on Bremsstrahlung photons, iii) to derive the thermodynamical properties of the excited nuclear sources and, in particular, to establish a 'caloric curve' (temperature versus excitation energy), and iv) to assess the time-scales of the nuclear break-up process. (author)

  2. Thermal Bremsstrahlung probing nuclear multifragmentation in nucleus-nucleus collisions around the Fermi energy; Bremsstrahlung thermique comme sonde de la multifragmentation nucleaire dans les collisions noyau-noyau aux energies de Fermi

    Energy Technology Data Exchange (ETDEWEB)

    D' Enterria, D.G

    2000-05-15

    The thermodynamical properties of nuclear matter at moderate temperatures and densities, in the vicinity of the predicted nuclear liquid-gas phase transition, are studied using as experimental probe the hard-photons (E{sub {gamma}} > 30 MeV) emitted in nucleus-nucleus collisions. Photon and charged-particle production in four different heavy-ion reactions (Ar{sup 36} + Au{sup 197}, Ag{sup 107}, Ni{sup 58}, C{sup 12} at 60 A*MeV) is measured exclusively and inclusively coupling the TAPS photon spectrometer with two charged-particle and intermediate-mass-fragment detectors covering nearly 4{pi}. We confirm that Bremsstrahlung emission in first-chance (off-equilibrium) proton-neutron collisions (pn{gamma}) is the dominant origin of hard photons. We also firmly establish the existence of a thermal radiation component emitted in second-chance proton-neutron collisions. This thermal Bremsstrahlung emission takes place in semi-central and central nucleus-nucleus reactions involving heavy targets. We exploit this observation i) to demonstrate that thermal equilibrium is reached during the reaction, ii) to establish a new thermometer of nuclear matter based on Bremsstrahlung photons, iii) to derive the thermodynamical properties of the excited nuclear sources and, in particular, to establish a 'caloric curve' (temperature versus excitation energy), and iv) to assess the time-scales of the nuclear break-up process. (author)

  3. Density oscillations of nuclear matter probed via Bremsstrahlung photons

    International Nuclear Information System (INIS)

    Marques, F.M.; Ostendorf, R.W.

    1996-01-01

    From the extended experimental data on hard-photon production at intermediate energies the dominant source of hard-photons has been attributed to the Bremsstrahlung radiation emitted in first-chance proton-neutron (pn) collisions. Aside of the dominant source which produces direct hard-photons, at intermediate energies BUU calculations predict the existence of a second source of pn Bremsstrahlung photons occurring at a later stage of the heavy-ion collision when the system is almost fully thermalized, thermal hard-photons. The existence of this second photon source is searched for by analysing the energy spectra of inclusive and exclusive hard-photons and the photon-photon correlation function for three different systems. (K.A.)

  4. Nuclear bremsstrahlung in proton induced reactions at 190 MeV (first experiments at AGOR)

    NARCIS (Netherlands)

    Wilschut, HW

    1998-01-01

    An overview is given of the first experiments with the new KVI cyclotron AGOR. First experiments have focused on nuclear bremsstrahlung in few-and many-body reactions. A classical introduction to nuclear bremsstrahlung is given. First results on coherent bremsstrahlung are discussed.

  5. Bremsstrahlung-induced highly penetrating probes for nondestructive assay and defect analysis

    CERN Document Server

    Selim, F A; Harmon, J F; Kwofie, J; Spaulding, R; Erickson, G; Roney, T

    2002-01-01

    Nondestructive assay and defect analysis probes based on bremsstrahlung-induced processes have been developed to identify elements and probe defects in large volume samples. Bremsstrahlung beams from (electron accelerators) with end-point energies both above and below neutron emission threshold have been used. Below neutron emission threshold these beams (from 6 MeV small pulsed linacs), which exhibit high penetration, create positrons via pair production inside the material and produce X-ray fluorescence (XRF) radiation. Chemical assays of heavy elements in thick samples up to 10 g/cm sup 2 thick are provided by energy dispersive XRF measurements. The pair-produced positrons annihilate within the material, thereby emitting 511 keV gamma radiation. Doppler broadening spectroscopy of the 511 keV radiation can be performed to characterize the material and measure defects in samples of any desired thickness. This technique has successfully measured induced strain due to tensile stress in steel samples of 0.64 cm...

  6. Neutron-proton bremsstrahlung from intermediate energy heavy-ion reactions as a probe of the nuclear symmetry energy?

    International Nuclear Information System (INIS)

    Yong, G.-C.; Li Baoan; Chen Liewen

    2008-01-01

    Hard photons from neutron-proton bremsstrahlung in intermediate energy heavy-ion reactions are examined as a potential probe of the nuclear symmetry energy within a transport model. Effects of the symmetry energy on the yields and spectra of hard photons are found to be generally smaller than those due to the currently existing uncertainties of both the in-medium nucleon-nucleon cross sections and the photon production probability in the elementary process pn→pnγ. Very interestingly, nevertheless, the ratio of hard photon spectra R 1/2 (γ) from two reactions using isotopes of the same element is not only approximately independent of these uncertainties but also quite sensitive to the symmetry energy. For the head-on reactions of 132 Sn + 124 Sn and 112 Sn + 112 Sn at E beam /A=50 MeV, for example, the R 1/2 (γ) displays a rise up to 15% when the symmetry energy is reduced by about 20% at ρ=1.3ρ 0 which is the maximum density reached in these reactions

  7. Nuclear effects on bremsstrahlung neutrino rates of astrophysical interest

    International Nuclear Information System (INIS)

    Stoica, Sabin; Horvath, J.E.

    2002-01-01

    We calculate in this work the rates for the neutrino pair production by nucleon-nucleon bremsstrahlung taking into account the full contribution from a nuclear one-pion-exchange potential. It is shown that if the temperatures are low enough (T≤20 MeV), the integration over the nuclear part can be done for the general case, ranging from the completely degenerate (D) to the nondegenerate (ND) regime. We find that the inclusion of the full nuclear contribution enhances the neutrino pair production by nn and pp bremsstrahlung by a factor of about 2 in both the D and ND limits when compared with previous calculations. This result may be relevant for the physical conditions of interest in the semitransparent regions near the neutrinosphere in type II supernovae, cooling of neutron stars, and other astrophysical situations

  8. Beta Bremsstrahlung dose in concrete shielding

    Energy Technology Data Exchange (ETDEWEB)

    Manjunatha, H.C., E-mail: manjunatha@rediffmail.com [Department of Physics, Government college for women, Kolar 563101, Karnataka (India); Chandrika, B.M. [Shravana, 592, Ist Cross, Behind St.Anne s School, PC Extension, Kolar 563101, Karnataka (India); Rudraswamy, B. [Department of Physics, Bangalore University, Bangalore 560056, Karnataka (India); Sankarshan, B.M. [Shravana, 592, Ist Cross, Behind St.Anne s School, PC Extension, Kolar 563101, Karnataka (India)

    2012-05-11

    In a nuclear reactor, beta nuclides are released during nuclear reactions. These betas interact with shielding concrete and produces external Bremsstrahlung (EB) radiation. To estimate Bremsstrahlung dose and shield efficiency in concrete, it is essential to know Bremsstrahlung distribution or spectra. The present work formulated a new method to evaluate the EB spectrum and hence Bremsstrahlung dose of beta nuclides ({sup 32}P, {sup 89}Sr, {sup 90}Sr-{sup 90}Y, {sup 90}Y, {sup 91}Y, {sup 208}Tl, {sup 210}Bi, {sup 234}Pa and {sup 40}K) in concrete. The Bremsstrahlung yield of these beta nuclides in concrete is also estimated. The Bremsstrahlung yield in concrete due to {sup 90}Sr-{sup 90}Y is higher than those of other given nuclides. This estimated spectrum is accurate because it is based on more accurate modified atomic number (Z{sub mod}) and Seltzer's data, where an electron-electron interaction is also included. Presented data in concrete provide a quick and convenient reference for radiation protection. The present methodology can be used to calculate the Bremsstrahlung dose in nuclear shielding materials. It can be quickly employed to give a first pass dose estimate prior to a more detailed experimental study. - Highlights: Black-Right-Pointing-Pointer Betas released in a nuclear reactor interact with shielding concrete and produces Bremsstrahlung. Black-Right-Pointing-Pointer The present work formulated a new method to evaluate the Bremsstrahlung spectrum and dose in concrete. Black-Right-Pointing-Pointer Presented data in concrete provide a quick and convenient reference for radiation protection.

  9. Neutron-proton bremsstrahlung experiments

    Energy Technology Data Exchange (ETDEWEB)

    Koster, J.E. (Los Alamos National Lab., NM (United States)); Nelson, R.O. (Los Alamos National Lab., NM (United States)); Schillaci, M.E. (Los Alamos National Lab., NM (United States)); Wender, S.A. (Los Alamos National Lab., NM (United States)); Mayo, D. (Univ. of California at Davis, CA (United States)); Brady, F.P. (Univ. of California at Davis, CA (United States)); Romero, J. (Univ. of California at Davis, CA (United States)); Krofcheck, D. (Lawrence Livermore National Lab., CA (United States)); Blann, M. (Lawrence Livermore National Lab., CA (United States)); Anthony, P. (Lawrence Livermore National Lab., CA (United States)); Brown, V.R. (Lawrence Livermore National Lab., CA (United States)); Hansen, L. (Lawrence Livermore National Lab., CA (United States)); Pohl, B. (Lawrence Livermore National Lab., CA (United States)); Sangster, T.C. (Lawrence Livermore National Lab., CA (United States)); Nifenecker, H. (Inst. des Sciences Nucleaires, Grenoble (France)); Pinston,

    1993-06-01

    It is well known that charged particles emit bremsstrahlung radiation when they are accelerated. Classical electron bremsstrahlung occurs when a proton is emitted by an electron accelerated in the field of a nucleus. The bremsstrahlung process also occurs in the scattering of nucleons, for which it is the lowest energy inelastic process that can occur. Like electron bremsstrahlung, nucleon-nucleon bremsstrahlung also requires the exchange of a virtual particle to conserve energy and momentum. In electron bremsstrahlung a virtual photon is exchanged but with two nucleons a meson can be exchanged. Unlike electron bremsstrahlung, in nucleon-nucleon bremsstrahlung the photon can originate from the exchanged meson. This exchange contribution has been shown in calculations to be a significant fraction of bremsstrahlung events. Thus bremsstrahlung serves as a probe of exchange currents in the nucleon-nucleon interaction. Because of a lack of a free neutron target or an intense neutron beam, few measurements of neutron-proton bremsstrahlung exist, each having poor statistical accuracy and poor energy resolution. The white neutron source at the Weapons Neutron Research (WNR) target area at the Los Alamos Meson Physics Facility (LAMPF) produces neutrons with energies from below 50 to above 400 MeV. Using time-of-flight techniques and a liquid hydrogen target, we are measuring the outgoing photons of energies up to 250 MeV at gamma ray angles of around 90 relative to the incident beam. Protons scattered at very forward angles are also detected in coincidence with the gamma rays. (orig.)

  10. Evaluation of electon and nuclear bremsstrahlung in heavy ion collisions

    International Nuclear Information System (INIS)

    Gippner, P.

    1975-01-01

    The detection of quasimolecular X-ray continua provides the possibility of investigating the electron shells of quasimolecules transiently formed during adiabatic heavy ion-atomic collision. The contribution of the electron and nuclear bremsstrahlung to quasimolecular X-ray continua observed in bombarding various targets with 65 and 96 MeV Nb ions were estimated

  11. Probing few-body systems with bremsstrahlung

    NARCIS (Netherlands)

    Kalantar-Nayestanaki, N; Krivec, R; Golli, B; Rosina, M; Sirca, S

    2003-01-01

    A series of bremsstrahlung measurements have been performed with the superconducting cyclotron, AGOR, at KVI. These measurements, on the proton-proton and proton-deuteron systems, aim to investigate the nucleon-nucleon interaction far away from elastic channel. Cross sections and analyzing powers

  12. Probing few-body systems with bremsstrahlung

    NARCIS (Netherlands)

    Kalantar-Nayestanaki, N; Kruppa, AT; Lovas, RG

    2002-01-01

    A series of bremsstrahlung measurements have been performed with the superconducting cyclotron, AGOR, at KVI. These measurements, on the proton-proton and proton-deuteron systems, aim to investigate the nucleon-nucleon interaction as the nucleons go off their mass shell. Cross sections and analyzing

  13. Probing few-body systems with bremsstrahlung

    NARCIS (Netherlands)

    Kalantar-Nayestanaki, N; Oryu, S; Kamimura, M; Ishikawa, S

    2000-01-01

    A series of bremsstrahlung measurements have been performed with the superconducting cyclotron, AGOR, at KVI. These measurements, on the proton-proton and proton-deuteron systems, aim to investigate the nucleon-nucleon interaction as the nucleons go off their mass shelf. Cross sections and analyzing

  14. Comparison of different Bremsstrahlung converters and collimators for Nuclear Resonance Fluorescence setup at IFUSP

    International Nuclear Information System (INIS)

    Lopez, P.N; Corrales, Y.; Manso Guevara, M.V; Martins, M.N.

    2007-01-01

    Nuclear Resonance Fluorescence (NRF) setup will install in the new electron accelerator, which is in final stage of installation at the Physics Institute of Sao Paulo University (IFUSP). The Bremsstrahlung facility and the setup for photon scattering should be designed such that the background radiation caused by scattering photons and the production of neutrons is minimized. In this order the Monte Carlo simulation studies show the best options for the different elements of the NRF setup, and how to link these elements to the particularities of the irradiation room. In the present stage the simulations has been included the studies of different Bremsstrahlung converters and collimators. Several materials (Ta, W, Au, Nb, Cu) for Bremsstrahlung converters were studied. Detailed analyses of intensity as well as the opening angles of Bremsstrahlung radiation were carried out, for different converter thickness. For the collimator two materials (Cu and Pb) were studied in the simulations. Several opening angles and thickness (40 - 100 cm) were studied. The Bremsstrahlung beam collimation for different energy bins, and the photon scattering from the collimator ,were used as quality parameters of the collimators. (Author)

  15. Suppression of soft nuclear bremsstrahlung in proton-nucleus collisions

    International Nuclear Information System (INIS)

    Goethem, M.J. van; Bacelar, J.C.S.; Hoefman, M.; Huisman, H.; Kalantar-Nayestanaki, N.; Loehner, H.; Messchendorp, J.G.; Ostendorf, R.W.; Schadmand, S.; Siemssen, R.H.; Turrisi, R.; Volkerts, M.; Wilschut, H.W.; Aphecetche, L.; Delagrange, H.; D'Enterria, D.; Martinez, G.; Schutz, Y.; Diaz, J.; Holzmann, R.

    2002-01-01

    Photon energy spectra up to the kinematic limit have been measured in 190 MeV proton reactions with light and heavy nuclei to investigate the influence of the multiple-scattering process on the photon production. Relative to the predictions of models based on a quasifree production mechanism, a strong suppression of bremsstrahlung is observed in the low-energy region of the photon spectrum. We attribute this effect to the interference of photon amplitudes due to multiple scattering of nucleons in the nuclear medium

  16. Polarizational radiation or 'atomic' bremsstrahlung

    International Nuclear Information System (INIS)

    Ya Amusia, M.

    1992-01-01

    It is demonstrated that a new kind of continuum spectrum radiation exists, where the mechanism of formation is quite different from that of ordinary bremsstrahlung. The latter originates due to slowing down of the charged projectile in the target field, while the former, called polarization radiation or 'atomic' bremsstrahlung, is a result of radiation either of the target or the projectile particles dipolarly polarized during the collision process. Not only general formulae, but also results of concrete calculations are presented. These demonstrate, that for electron-atom collisions the atomic contribution to the total bremsstrahlung spectrum becomes dominant for photon energies near and above the atomic ionization potential. As to atom-atom or ion-atom collisions, the bremsstrahlung spectrum is completely determined by the atomic contribution. The specific features of the case when the incoming particles are relativistic are discussed at length. A number of examples of colliding pairs are considered, for which the atomic bremsstrahlung process is quite essential: A bare nucleus and an atom, pair of atoms, at least one of which is excited, electron, or atom interacting with a molecule. The same mechanism is essential also in formation of radiation in nuclear and elementary particle collisions. (orig.)

  17. Bremsstrahlung from relativistic heavy ions in matter

    DEFF Research Database (Denmark)

    Sørensen, Allan Hvidkjær

    2010-01-01

    The emission of electromagnetic radiation by relativistic bare heavy ions penetrating ordinary matter is investigated. Our main aim is to determine the bremsstrahlung which we define as the radiation emitted when the projectile does not break up. It pertains to collisions without nuclear contact....... As a result of its relative softness, bremsstrahlung never dominates the energy-loss process for heavy ions. As to the emission of electromagnetic radiation in collisions with nuclear break-up, it appears modest when pertaining to incoherent action of the projectile nucleons in noncontact collisions...

  18. A novel nuclear pyrometry for the characterization of high-energy bremsstrahlung and electrons produced in relativistic laser-plasma interactions

    International Nuclear Information System (INIS)

    Guenther, M. M.; Sonnabend, K.; Harres, K.; Roth, M.; Brambrink, E.; Vogt, K.; Bagnoud, V.

    2011-01-01

    We present a novel nuclear activation-based method for the investigation of high-energy bremsstrahlung produced by electrons above 7 MeV generated by a high-power laser. The main component is a novel high-density activation target that is a pseudo alloy of several selected isotopes with different photo-disintegration reaction thresholds. The gamma spectrum emitted by the activated targets is used for the reconstruction of the bremsstrahlung spectrum using an analysis method based on Penfold and Leiss. This nuclear activation-based technique allows for the determination of the number of bremsstrahlung photons per energy bin in a wide range energy without any anticipated fit procedures. Furthermore, the analysis method also allows for the determination of the absolute yield, the energy distribution, and the temperature of high-energy electrons at the relativistic laser-plasma interaction region. The pyrometry is sensitive to energies above 7 MeV only, i.e., this diagnostic is insensitive to any low-energy processes.

  19. A novel nuclear pyrometry for the characterization of high-energy bremsstrahlung and electrons produced in relativistic laser-plasma interactions

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, M. M.; Sonnabend, K.; Harres, K.; Roth, M. [Institut fuer Kernphysik, Schlossgartenstr. 9, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Brambrink, E. [Laboratoire pour l' Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-Ecole Polytechnique-Universite Paris VI, F-91128 Palaiseau (France); Vogt, K.; Bagnoud, V. [GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, D-64291 Darmstadt (Germany)

    2011-08-15

    We present a novel nuclear activation-based method for the investigation of high-energy bremsstrahlung produced by electrons above 7 MeV generated by a high-power laser. The main component is a novel high-density activation target that is a pseudo alloy of several selected isotopes with different photo-disintegration reaction thresholds. The gamma spectrum emitted by the activated targets is used for the reconstruction of the bremsstrahlung spectrum using an analysis method based on Penfold and Leiss. This nuclear activation-based technique allows for the determination of the number of bremsstrahlung photons per energy bin in a wide range energy without any anticipated fit procedures. Furthermore, the analysis method also allows for the determination of the absolute yield, the energy distribution, and the temperature of high-energy electrons at the relativistic laser-plasma interaction region. The pyrometry is sensitive to energies above 7 MeV only, i.e., this diagnostic is insensitive to any low-energy processes.

  20. Probing Sub-GeV Dark Matter with Conventional Detectors

    DEFF Research Database (Denmark)

    Kouvaris, Chris; Pradler, Josef

    2017-01-01

    The direct detection of dark matter particles with mass below the GeV scale is hampered by soft nuclear recoil energies and finite detector thresholds. For a given maximum relative velocity, the kinematics of elastic dark matter nucleus scattering sets a principal limit on detectability. Here, we...... propose to bypass the kinematic limitations by considering the inelastic channel of photon emission from bremsstrahlung in the nuclear recoil. Our proposed method allows us to set the first limits on dark matter below 500 MeV in the plane of dark matter mass and cross section with nucleons. In situations...... where a dark-matter-electron coupling is suppressed, bremsstrahlung may constitute the only path to probe low-mass dark matter awaiting new detector technologies with lowered recoil energy thresholds....

  1. Probing Sub-GeV Dark Matter with Conventional Detectors.

    Science.gov (United States)

    Kouvaris, Chris; Pradler, Josef

    2017-01-20

    The direct detection of dark matter particles with mass below the GeV scale is hampered by soft nuclear recoil energies and finite detector thresholds. For a given maximum relative velocity, the kinematics of elastic dark matter nucleus scattering sets a principal limit on detectability. Here, we propose to bypass the kinematic limitations by considering the inelastic channel of photon emission from bremsstrahlung in the nuclear recoil. Our proposed method allows us to set the first limits on dark matter below 500 MeV in the plane of dark matter mass and cross section with nucleons. In situations where a dark-matter-electron coupling is suppressed, bremsstrahlung may constitute the only path to probe low-mass dark matter awaiting new detector technologies with lowered recoil energy thresholds.

  2. Proton-proton bremsstrahlung

    International Nuclear Information System (INIS)

    Fearing, H.W.

    1990-01-01

    We summarize some of the information about the nucleon-nucleon force which has been obtained by comparing recent calculations of proton-proton bremsstrahlung with cross section and analyzing power data from the new TRIUMF bremsstrahlung experiment. Some comments are made as to how these results can be extended to neutron-proton bremsstrahlung. (Author) 17 refs., 6 figs

  3. The TAC Radiation Source for Bremsstrahlung Application

    International Nuclear Information System (INIS)

    Demir, N.

    2008-01-01

    The TAC is a project for the first Turkish radiation source and currently design study is produced with funding from the DPT (State Planning Unity). Two main part of the project will be IR-FEL and Bremsstrahlung facility. Each LINAC will provide max. electron energy of 20 MeV. The Bremsstrahlung facility at TAC will consist two of the LINAC module and will be obtained 35 MeV photon energy. This would provide a chance to investigate nuclear structure at this energy range and also some application of photonuclear physics. In this work the main parameter and plans for those of facility will be detailed

  4. Pion-proton bremsstrahlung

    International Nuclear Information System (INIS)

    Liou, M.K.; Nutt, W.T.

    1978-01-01

    A method for applying the soft-photon theorem to bremsstrahlung is described and a detailed derivation of the formulae for π + -p bremsstrahlung is presented. The consistent treatment of the expansion of the bremsstrahlung cross-section around k=0 results in excellent fits to the experimental data. The data are consistent with small off-shell effects and no radiation from the Δ(1236) resonance

  5. Virtual-bremsstrahlung production in proton-proton scattering and proton-deuteron capture

    NARCIS (Netherlands)

    Messchendorp, Johannes Gerhardus

    1999-01-01

    The well-known coupling of the photon with the nucleon together with the fact that photons (or any electromagnetic (e.m.) probe) interact only relatively weakly with nucleons, make bremsstrahlung production an ideal tool to study details of the nucleon-nucleon interaction. In this thesis dilepton

  6. Electron - atom bremsstrahlung

    International Nuclear Information System (INIS)

    Kim, L.

    1986-01-01

    Features of bremsstrahlung radiation from neutral atoms and atoms in hot dense plasmas are studied. Predictions for the distributions of electron-atom bremsstrahlung radiation for both the point-Coulomb potential and screened potentials are obtained using a classical numerical method. Results agree with exact quantum-mechanical partial-wave results for low incident electron energies in both the point-Coulomb and screened potentials. In the screened potential, the asymmetry parameter of a spectrum is reduced from the Coulomb values. The difference increases with decreasing energy and begins to oscillate at very low energies. The scaling properties of bremsstrahlung spectra and energy losses were also studied. It was found that the ratio of the radiative energy loss for positrons to that for electrons obeys a simple scaling law, being expressible fairly accurately as a function only of the quantity T 1 /Z 2 . This scaling is exact in the case of the point-Coulomb potential, both for classical bremsstrahlung and for the nonrelativistic dipole Sommerfeld formula. Bremsstrahlung from atoms in hot dense plasmas were also studied describing the atomic potentials by the temperature-and-density dependent Thomas-Fermi mode. Gaunt factors were obtained with the relativistic partial-wave method for atoms in plasmas of various densities and temperatures

  7. The elementary process of Bremsstrahlung

    CERN Document Server

    Haug, Eberhard

    2004-01-01

    This book deals with the theory and experiment of the elementary process of bremsstrahlung, where photons are detected in coincidence with decelerated outgoing electrons. Such experiments allow for a more stringent check of the theoretical work. The main emphasis is laid on electron-atom bremsstrahlung and electron-electron bremsstrahlung, but further bremsstrahlung processes are also dealt with. In the theoretical parts, triply differential cross sections are derived in various approximations, including electron spin and photon-polarization. In the experimental sections, electron-photon coinc

  8. Bremsstrahlung in atom-atom collisions

    International Nuclear Information System (INIS)

    Amus'ya, M.Y.; Kuchiev, M.Y.; Solov'ev, A.V.

    1985-01-01

    It is shown that in the collision of a fast atom with a target atom when the frequencies are on the order of the potentials or higher, there arises bremsstrahlung comparable in intensity with the bremsstrahlung emitted by an electron with the same velocity in the field of the target atom. The mechanism by which bremsstrahlung is produced in atom-atom collisions is elucidated. Results of specific calculations of the bremsstrahlung spectra are given for α particles and helium atoms colliding with xenon

  9. Bremsstrahlung Based Positron Annihilation Spectroscopy for Material Defect Analysis

    International Nuclear Information System (INIS)

    Selim, F.A.; Wells, D.P.; Harmon, F.; Kwofie, J.; Lancaster, G.; Jones, J.L.

    2003-01-01

    The Idaho Accelerator Center (IAC) has developed new techniques for Positron Annihilation Spectroscopy (PAS) using highly penetrating γ-rays to create positrons inside the material via pair production. γ-Ray induced positron annihilation spectroscopy can provide highly penetrating probes for material characterization and defect analysis. Bremsstrahlung beams from small, pulsed electron Linacs (6 MeV) have been used to bombard the materials to generate positrons, which annihilate with the material electrons emitting 511 keV radiation. We have also synchronized bremsstrahlung pulses with laser irradiation pulses to study dynamic structural changes in material. In addition, we have developed another method using (p,γ) reactions from a 2 MeV proton beam, which induce coincident γ-rays to perform positron life-time spectroscopy. We have showed the feasibility of extending PAS into thick samples and a wide variety of materials and industrial applications

  10. Dose Measurements of Bremsstrahlung-Produced Neutrons at the Advanced Photon Source

    International Nuclear Information System (INIS)

    Job, P.K.; Pisharody, M.; Semones, E.

    1998-01-01

    Bremsstrahlung is generated in the storage rings of the synchrotron radiation facilities by the radiative interaction of the circulating particle beam with both the residual gas molecules and storage ring components. These bremsstrahlung photons, having an energy range of zero to the maximum energy of the particle beam, interact with beamline components like beam stops and collimators generating photoneutrons of varying energies. There are three main processes by which photoneutrons may be produced by the high energy bremsstrahlung photons: giant nuclear dipole resonance and decay (10 MeV γ γ γ > 140 MeV). The giant resonance neutrons are emitted almost isotropically and have an average energy of about 2 MeV. High energy neutrons (E > 10 MeV) emitted from the quasi-deuteron decay and intranuclear cascade are peaked in the forward direction. At the Advanced Photon Source (APS), where bremsstrahlung energy can be as high as 7 GeV, production of photoneutrons in varying yields is possible from all of the above three processes. The bremsstrahlung produced along a typical 15.38-m straight path of the insertion device (ID) beamline of the APS has been measured and analyzed in previous studies. High-Z materials constituting the beamline components, such as collimators and beam stops, can produce photoneutrons upon interaction with these bremsstrahlung photons. The 1/E nature of the bremsstrahlung spectrum and the fact that the photoneutron production cross section is comparatively larger in the energy region 10 MeV γ 3 detector, as well as a very sensitive pressurized 3 He detector, is used for neutron dose measurements. The dose equivalent rates, normalized to bremsstrahlung power, beam current, and storage ring vacuum, are measured for various targets. This report details the experimental setup,

  11. Polarization bremsstrahlung in α decay

    International Nuclear Information System (INIS)

    Amusia, M. Ya.; Zon, B. A.; Kretinin, I. Yu.

    2007-01-01

    A mechanism of formation of electromagnetic radiation that accompanies α decay and is associated with the emission of photons by electrons of atomic shells due to the scattering of α particles by these atoms (polarization bremsstrahlung) is proposed. It is shown that, when the photon energy is no higher than the energy of K electrons of an atom, polarization bremsstrahlung makes a significant contribution to the bremsstrahlung in α decay

  12. Study of nuclear bremsstrahlung in the model independent approach

    International Nuclear Information System (INIS)

    Liu, C.K.

    1980-01-01

    The bremsstrahlung cross section for the scattering of protons by 12 C near the 1.7-MeV resonance has been measured by the Bologna group and the Brooklyn group. In this study, we have included in our calculations the correction terms in the Feshbach-Yennie approximation and have extracted the time delay in the P- 12 C reaction from the data of the Brooklyn group. The + p process near the (1236) has been systematically studied by an experimental group at UCLA. Recently, Liou and Nutt reported a calculation using the soft-photon approximation and their results agree very well with experiment for coplanar events. We have extended their calculation to noncoplanar cases and have found that the soft-photon approximation of Liou and Nutt can describe the experimental data very well not only for coplanar cases but also for noncoplanar cases for most photon angles. In addition, we have also used the Feshbach-Yennie approximation to calculate the + p cross sections. This approximation always predicts a bump in the bremsstrahlung spectrum, although the bump may be small for some photon angles. In most cases, the predicted cross sections are in good agreement with the UCLA data. However, the data for some angles can only be described by the Feshbach-Yennie approximation, and the peak cross section is too large at some angles. We have applied the soft-photon approximation of Liou and Nutt to calculate the proton-proton bremsstrahlung (pp) cross section and have compared our results with the experimental data at 730, 157, 48 and 42 MeV. We have found that we can use the soft-photon approximation to calculate the R-type cross section without any difficulty, but we cannot use the same approximation to predict the H-type cross section without some ambiguity. We have also applied the Feshbach-Yennie approximation to the pp process at 730-MeV taking into account the principal and correction terms

  13. Beta Emission and Bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-13

    Bremsstrahlung is continuous radiation produced by beta particles decelerating in matter; different beta emitters have different endpoint energies; high-energy betas interacting with high-Z materials will more likely produce bremsstrahlung; depending on the data, sometimes all you can say is that a beta emitter is present.

  14. International Conference on Spin Observables of Nuclear Probes

    CERN Document Server

    Goodman, Charles; Walker, George; Spin Observables of Nuclear Probes

    1988-01-01

    The proceedings of the "International Conference on Spin Observables of Nuclear Probes" are presented in this volume. This conference was held in Telluride, Colorado, March 14 -17, 1988, and was the fourth in the Telluride series of nuclear physics conferences. A continuing theme in the Telluride conference series has been the complementarity of various intermediate-energy projectiles for elucidating the nucleon-nucleon interaction and nuclear structure. Earlier conferences have contributed significantly to an understanding of spin currents in nuclei, in particular the distribution of Gamow-Teller strength using charge-exchange reactions. The previous conference on "Antinucleon and Nucleon Nucleus Interactions" compared nuclear information from tra­ tional probes to recent results from antinucleon reactions. The 1988 conference on Spin Observables of Nuclear Probes, put special emphasis on spin observables and brought together experts using spin information to probe nuclear structure. Spin observabl...

  15. Bremsstrahlung and neutral currents

    International Nuclear Information System (INIS)

    Ellis, R.G.; McKellar, B.H.J.

    1979-01-01

    The utility of the bremsstrahlung process in detecting parity violations from V-A weak neutral current interference is analysed in two ways. Firstly, bremsstrahlung from polarized lepton-nucleus scattering has an asymmetry with respect to the polarization of the incident leptons, and secondly, bremsstrahlung from unpolarized lepton nucleus scattering has a small circular polarization. The magnitude of each effect is calculated. The ratio of the parity violating contribution and the parity conserving contribution to the cross section is shown to be a misleading measure of the utility of these experiments. A parameter, the figure of merit, is introduced and used to discuss the feasibility of possible experiments

  16. Probing nuclear matter with dileptons

    International Nuclear Information System (INIS)

    Schroeder, L.S.

    1986-06-01

    Dileptons are shown to be of interest in helping probe extreme conditions of temperature and density in nuclear matter. The current state of experimental knowledge about dileptons is briefly described, and their use in upcoming experiments with light ions at CERN SPS are reviewed, including possible signatures of quark matter formation. Use of dileptons in an upcoming experiment with a new spectrometer at Berkeley is also discussed. This experiment will probe the nuclear matter equation of state at high temperature and density. 16 refs., 8 figs

  17. Bremsstrahlung from Relativistic Heavy Ions in a Fixed Target Experiment at the LHC

    International Nuclear Information System (INIS)

    Mikkelsen, Rune E.; Uggerhøj, Ulrik I.; Sørensen, Allan H.

    2015-01-01

    We calculate the emission of bremsstrahlung from lead and argon ions in ultraperipheral collisions in a fixed target experiment (AFTER) that uses the LHC beams. With nuclear charges of Ze equal to 82e and 18e, respectively, these ions are accelerated to energies of 7 Tev × Z. The bremsstrahlung peaks around ≈100 GeV and the spectrum exposes the nuclear structure of the incoming ion. The peak structure is significantly different from the flat power spectrum pertaining to a point charge. Photons are predominantly emitted within an angle of 1/γ to the direction of ion propagation. Our calculations are based on the Weizsäcker-Williams method of virtual quanta with application of existing experimental data on photonuclear interactions.

  18. Comparison of Classical and Quantum Bremsstrahlung

    International Nuclear Information System (INIS)

    Pratt, R.H.; Uskov, D.B.; Korol, A.V.; Obolensky, O.I.

    2003-01-01

    Classical features persist in bremsstrahlung at surprisingly high energies, while quantum features are present at low energies. For Coulomb bremsstrahlung this is related to the similar properties of Coulomb scattering. For bremsstrahlung in a screened potential, the low energy spectrum and angular distribution exhibit structures. In quantum mechanics these structures are associated with zeroes of particular angular-momentum transfer matrix elements at particular energies, a continuation of the Cooper minima in atomic photoeffect. They lead to transparency windows in free-free absorption. The trajectories of these zeroes in the plane of initial and final transition energies (bound and continuum) has been explored. Corresponding features have now been seen in classical bremsstrahlung, resulting from reduced contributions from particular impact parameters at particular energies. This has suggested the possibility of a more unified treatment of classical and quantum bremsstrahlung, based on the singularities of the scattering amplitude in angular momentum

  19. Calculation of Bremsstrahlung yield for thin target

    International Nuclear Information System (INIS)

    Demir, N.; Akkurt, I.; Tekin, H. O.; Cakirli, R. B.; Akkus, B.; Kupa, I.

    2010-01-01

    The Bremsstrahlung photon is created by de-accelerating electron beam in an electric field which is usually a thin material so-called radiator. The obtained Bremsstrahlung yield depends on some parameter such as incoming electron beam energy, the thickness and also Z number of the radiator. The main aim of this work is to obtain optimum radiator to be used at Bremsstrahlung photon beam facility at TAC. For this purposes the Bremsstrahlung photon yield has been obtained using FLUKA code for different types materials.

  20. Beta induced Bremsstrahlung dose rate in concrete shielding

    International Nuclear Information System (INIS)

    Manjunatha, H.C.

    2013-01-01

    Dosimetric study of beta-induced Bremsstrahlung in concrete is importance in the field of radiation protection. The efficiency, intensity and dose rate of beta induced Bremsstrahlung by 113 pure beta nuclides in concrete shielding is computed. The Bremsstrahlung dosimetric parameters such as the efficiency (yield), Intensity and dose rate of Bremsstrahlung are low for 199 Au and high for 104 Tc in concrete. The efficiency, Intensity and dose rate of Bremsstrahlung increases with maximum energy of beta nuclide (Emax) and modified atomic number (Zmod) of the target. The estimated Bremsstrahlung efficiency, Intensity and dose rate are useful in the calculations photon track-length distributions. These parameters are useful to determine the quality and quantity of the radiation (known as the source term). Precise estimation of this source term is very important in planning of radiation shielding. (author)

  1. Limits for an inverse bremsstrahlung origin of the diffuse Galactic soft gamma-ray emission

    DEFF Research Database (Denmark)

    Pohl, M.

    1998-01-01

    origin of the soft Galactic gamma-ray continuum through inverse bremsstrahlung. A flux of low-energy cosmic rays strong enough to produce the observed spectrum of gamma-rays implies substantial gamma-ray emission at a few MeV through nuclear de-excitation. It is shown that the existing limits on excess 3......-7 MeV emission from the Galactic plane, in concert with the constraints from pi(0)-decay gamma-ray emission at higher energies, are in serious conflict with an inverse bremsstrahlung origin of the Galactic soft gamma-ray emission for any physically plausible low-energy cosmic ray spectrum. While...

  2. Nuclear physics with electroweak probes

    International Nuclear Information System (INIS)

    Benhar, Omar

    2009-01-01

    In recent years, the italian theoretical Nuclear Physics community has played a leading role in the development of a unified approach, allowing for a consistent and fully quantitative description of the nuclear response to electromagnetic and weak probes. In this paper I review the main achievements in both fields, point out some of the open problems, and outline the most promising prospects

  3. High energy bremsstrahlung in an intense laser field

    International Nuclear Information System (INIS)

    Schlessinger, L.; Wright, J.A.

    1980-02-01

    The cross section for bremsstrahlung emission and absorption by electrons in an intense laser field has been calculated in the Born approximation for the electron-ion potential. Typical numerical results are presented as a function of the ratio of the electron guiver energy to its energy and the ratio of the bremsstrahlung energy to the electron energy. The intense field correction factor for the rate of bremsstrahlung emission and absorption for electrons with a Boltzmann distribution of energies has been calculated. Numerical results for the correction factor are presented for the Boltzmann case as a function of the ratio of the electron quiver energy to its thermal energy and the ratio of the bremsstrahlung energy to the thermal energy. For typical laser fusion parameters, this correction factor which is the ratio of the thermal bremsstrahlung emission rate in the intense laser field to the rate at zero field can be quite significant. For a laser of wavelength 1.06 μm at an intensity of 3 x 10 15 w/cm 2 and an electron temperature of 1 keV, the correction factor varies from 0.98 at a bremsstrahlung energy of 100 V to greater than 5 at a bremsstrahlung energy of 10 keV

  4. Collimator and energy window optimization for 90Y bremsstrahlung SPECT imaging: A SIMIND Monte Carlo study

    International Nuclear Information System (INIS)

    Roshan, Hoda Rezaei; Mahmoudian, Babak; Gharepapagh, Esmaeil; Azarm, Ahmadreza; Pirayesh Islamian, Jalil

    2016-01-01

    Treatment efficacy of radioembolization using Yttrium-90 ( 90 Y) microspheres is assessed by the 90 Y bremsstrahlung single photon emission computed tomography (SPECT) imaging following radioembolization. The radioisotopic image has the potential of providing reliable activity map of 90 Y microspheres distribution. One of the main reasons of the poor image quality in 90 Y bremsstrahlung SPECT imaging is the continuous and broad energy spectrum of the related bremsstrahlung photons. Furthermore, collimator geometry plays an impressive role in the spatial resolution, sensitivity and image contrast. Due to the relatively poor quality of the 90 Y bremsstrahlung SPECT images, we intend to optimize the medium-energy (ME) parallel-hole collimator and energy window. The Siemens e.cam gamma camera equipped with a ME collimator and a voxelized phantom was simulated by the SImulating Medical Imaging Nuclear Detectors (SIMIND) program. We used the SIMIND Monte Carlo program to generate the 90 Y bremsstrahlung SPECT projection of the digital Jaszczak phantom. The phantom consist of the six hot spheres ranging from 9.5 to 31.8 mm in diameter, which are used to evaluate the image contrast. In order to assess the effect of the energy window on the image contrast, three energy windows ranging from 60 to 160 KeV, 160 to 400 KeV, and 60 to 400 KeV were set on a 90 Y bremsstrahlung spectrum. As well, the effect of the hole diameter of a ME collimator on the image contrast and bremsstrahlung spectrum were investigated. For the fixed collimator and septa thickness values (3.28 cm and 1.14 mm, respectively), a hole diameter range (2.35–3.3 mm) was chosen based on the appropriate balance between the spatial resolution and sensitivity. The optimal energy window for 90 Y bremsstrahlung SPECT imaging was extended energy window from 60 to 400 KeV. Besides, The optimal value of the hole diameter of ME collimator was obtained 3.3 mm. Geometry of the ME parallel-hole collimator and energy

  5. Bremsstrahlung: an experimentalists personal perspective on the post modern era

    International Nuclear Information System (INIS)

    Quarles, C.A.

    2000-01-01

    In this brief review I will discuss the recent experimental work on the doubly differential cross section, i.e. the photon energy and angular distribution, for electron Bremsstrahlung from thin solid film and gas targets. Since the beginning of the modern era in the study of Bremsstrahlung with the publication of the 1971 paper by Ts eng and Pratt, Professor Pratt has been the dominant influence in Bremsstrahlung research. Most, if not all, experimental research during the modern era has been motivated by the interest in comparing data with the theory of Pratt and his coworkers. As Bremsstrahlung research has moved into its post modern era, new experiments with increasing precision are concentrating on determining under what conditions ordinary Bremsstrahlung theory needs to be supplemented by a contribution from polarization Bremsstrahlung. Efforts to improve the comparison of thin-target experiment with theory have also led to new experimental and modeling work on Bremsstrahlung from thick solid targets. Thick-target Bremsstrahlung is interesting in its own right, but we also want to understand it better since it is the ever-present background in the thin-target experiments and the limiting factor in the effort to distinguish the polarization contribution to the total Bremsstrahlung spectrum. Professor Pratt ushered in the modern era in Bremsstrahlung research and has recently guided the transition into the post modern era. It can be expected that he will continue to have a formative influence on the developments of Bremsstrahlung research into the foreseeable future.

  6. Internal bremsstrahlung signatures in light of direct dark matter searches

    International Nuclear Information System (INIS)

    Garny, Mathias; Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan

    2013-07-01

    Although proposed long ago, the search for internal bremsstrahlung signatures has only recently been made possible by the excellent energy resolution of ground-based and satellite-borne gamma-ray instruments. Here, we investigate thoroughly the current status of internal bremsstrahlung searches in light of the results of direct dark matter searches and in the framework of minimal mass-degenerate scenarios. The constraints set by Fermi-LAT and H.E.S.S. extend uninterrupted from tens of GeV up to tens of TeV and are rather insensitive to the mass degeneracy in the particle physics model. In contrast, direct searches are best in the moderate to low mass splitting regime, where XENON100 limits overshadow Fermi-LAT and H.E.S.S. up to TeV masses if dark matter couples to (light) quarks. We examine carefully the prospects for GAMMA-400, CTA and XENON1T, all planned to come online in the near future, and find that: (a) CTA and XENON1T are fully complementary, with CTA most sensitive to multi-TeV masses and mass splittings around 10%, and XENON1T probing best small mass splittings up to TeV masses; and (b) current constraints from XENON100 already preclude the observation of any spectral feature with GAMMA-400 in spite of its impressive energy resolution, unless dark matter does not couple to light quarks. Finally, we point out that, unlike for direct searches, the possibility of detecting thermal relics in upcoming internal bremsstrahlung searches requires boost factors larger than ∝10.

  7. Internal bremsstrahlung signatures in light of direct dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Garny, Mathias [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan [Technische Univ. Muenchen, Garching (Germany). Physik Dept. T30d

    2013-06-15

    Although proposed long ago, the search for internal bremsstrahlung signatures has only recently been made possible by the excellent energy resolution of ground-based and satellite-borne gamma-ray instruments. Here, we investigate thoroughly the current status of internal bremsstrahlung searches in light of the results of direct dark matter searches and in the framework of minimal mass-degenerate scenarios. The constraints set by Fermi-LAT and H.E.S.S. extend uninterrupted from tens of GeV up to tens of TeV and are rather insensitive to the mass degeneracy in the particle physics model. In contrast, direct searches are best in the moderate to low mass splitting regime, where XENON100 limits overshadow Fermi-LAT and H.E.S.S. up to TeV masses if dark matter couples to (light) quarks. We examine carefully the prospects for GAMMA-400, CTA and XENON1T, all planned to come online in the near future, and find that: (a) CTA and XENON1T are fully complementary, with CTA most sensitive to multi-TeV masses and mass splittings around 10%, and XENON1T probing best small mass splittings up to TeV masses; and (b) current constraints from XENON100 already preclude the observation of any spectral feature with GAMMA-400 in spite of its impressive energy resolution, unless dark matter does not couple to light quarks. Finally, we point out that, unlike for direct searches, the possibility of detecting thermal relics in upcoming internal bremsstrahlung searches requires boost factors larger than {proportional_to}10.

  8. Polarizational bremsstrahlung in non-relativistic collisions

    International Nuclear Information System (INIS)

    Korol, A.V.; Solov'yov, A.V.

    2006-01-01

    We review the developments made during the last decade in the theory of polarization bremsstrahlung in the non-relativistic domain. A literature survey covering the latest history of the phenomenon is given. The main features which distinguish the polarization bremsstrahlung from other mechanisms of radiation are discussed and illustrated by the results of numerical calculations

  9. Lepton probes in nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Arvieux, J. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1994-12-31

    Facilities are overviewed which use the lepton probe to learn about nuclear physics. The lepton accelerating methods out some existing facilities are considered. The ELFE project is discussed in detail. (K.A.). 43 refs., 15 figs., 4 tabs.

  10. Lepton probes in nuclear physics

    International Nuclear Information System (INIS)

    Arvieux, J.

    1994-01-01

    Facilities are overviewed which use the lepton probe to learn about nuclear physics. The lepton accelerating methods out some existing facilities are considered. The ELFE project is discussed in detail. (K.A.). 43 refs., 15 figs., 4 tabs

  11. Shielding calculation for bremsstrahlung from β-emitters

    International Nuclear Information System (INIS)

    Ichimiya, Tsutomu

    1990-01-01

    Accompanying the revision of radiation injury prevention law, the shielding calculation method for photon corresponding to the dose equivalent was shown. However, regarding the electron from β decay nuclide and bremsstrahlung caused by shielding material, the shielding calculation method corresponding to the 1 cm dose equivalent has not been reported, hence, in this report, the spectrum of β-ray is calculated and the 1 cm dose equivalent transmission rate of the bremsstrahlung was calculated for three kinds of shielding materials (iron, lead, concrete). As the result of consideration, it is sufficient to think about the bremsstrahlung due to negative electron emission accompanying β-decay. In β-decay, electrons which constitute the continuous spectrum with maximum energy are emitted. The shape of the spectrum differs with nuclides. The maximum energy of β-ray of generally used nuclides is mostly below 3MeV and, besides, the electron ray itself is easily shielded, while the strength of bremsstrahlung depends on the atomic number of shielding materials and its generating mechanism is complicated. In this report, the actual shielding calculation method for bremsstrahlung is shown with regard to the most frequently used β-decay nuclides. (M.T.)

  12. Dynamic bremsstrahlung from relativistic particles scattered by atom

    International Nuclear Information System (INIS)

    Astapenko, V.A.; Bujmistrov, V.M.; Krotov, Yu.A.; Mikhajlov, L.K.; Trakhtenberg, L.I.

    1985-01-01

    The bremsstrahlung cross section for a relativistic particle scattered by an atom is calculated. In contrast to the screening approximation usually employed, the influence of the atomic electron on the bremsstrahlung is taken into account exactly, viz., the atomic electron is considered as a moving particle interacting with the electromagnetic field and not only as the source of a static external field. Consequently, along with the static term which leads to the Bethe-Heitw,ler formula, a ne dynamic, term appears in the transition amplitude. The corresponding cross section, the dynamic bremsstrahlung cross section, in certain frequensy ranges and certain ranges of the directions of photon emission exceeds considerably the static bremsstrahlung cross section

  13. The resonance Bremsstrahlung of a fast charged particle in a medium

    International Nuclear Information System (INIS)

    Beshtoev, Kh.M.

    1998-01-01

    The Bremsstrahlung of the fast charged particle in the medium with dielectric permittivity ε at velocities υ ≥ c/n (n 2 =Reε) is considered. The Bremsstrahlung has singularity at β = 1/ncosθ (β = υ/c, θ is an angle of the Bremsstrahlung). This Bremsstrahlung is interpreted as resonance Bremsstrahlung with the width characterized by Imε=ε 2 , and the less ε 2 is, the higher the peak of this resonance rises. The angular distribution of the Bremsstrahlung is determined by cos θ=1/nβ and this angle coincides with the angle of the Cherenkov radiation. At β=1/n this resonance Bremsstrahlung goes in the forward direction and depends on frequency ω (ε=ε (ω))

  14. High-power, photofission-inducing bremsstrahlung source for intense pulsed active detection of fissile material

    Directory of Open Access Journals (Sweden)

    J. C. Zier

    2014-06-01

    Full Text Available Intense pulsed active detection (IPAD is a promising technique for detecting fissile material to prevent the proliferation of special nuclear materials. With IPAD, fissions are induced in a brief, intense radiation burst and the resulting gamma ray or neutron signals are acquired during a short period of elevated signal-to-noise ratio. The 8 MV, 200 kA Mercury pulsed-power generator at the Naval Research Laboratory coupled to a high-power vacuum diode produces an intense 30 ns bremsstrahlung beam to study this approach. The work presented here reports on Mercury experiments designed to maximize the photofission yield in a depleted-uranium (DU object in the bremsstrahlung far field by varying the anode-cathode (AK diode gap spacing and by adding an inner-diameter-reducing insert in the outer conductor wall. An extensive suite of diagnostics was fielded to measure the bremsstrahlung beam and DU fission yield as functions of diode geometry. Delayed fission neutrons from the DU proved to be a valuable diagnostic for measuring bremsstrahlung photons above 5 MeV. The measurements are in broad agreement with particle-in-cell and Monte Carlo simulations of electron dynamics and radiation transport. These show that with increasing AK gap, electron losses to the insert and outer conductor wall increase and that the electron angles impacting the bremsstrahlung converter approach normal incidence. The diode conditions for maximum fission yield occur when the gap is large enough to produce electron angles close to normal, yet small enough to limit electron losses.

  15. High-power, photofission-inducing bremsstrahlung source for intense pulsed active detection of fissile material

    Science.gov (United States)

    Zier, J. C.; Mosher, D.; Allen, R. J.; Commisso, R. J.; Cooperstein, G.; Hinshelwood, D. D.; Jackson, S. L.; Murphy, D. P.; Ottinger, P. F.; Richardson, A. S.; Schumer, J. W.; Swanekamp, S. B.; Weber, B. V.

    2014-06-01

    Intense pulsed active detection (IPAD) is a promising technique for detecting fissile material to prevent the proliferation of special nuclear materials. With IPAD, fissions are induced in a brief, intense radiation burst and the resulting gamma ray or neutron signals are acquired during a short period of elevated signal-to-noise ratio. The 8 MV, 200 kA Mercury pulsed-power generator at the Naval Research Laboratory coupled to a high-power vacuum diode produces an intense 30 ns bremsstrahlung beam to study this approach. The work presented here reports on Mercury experiments designed to maximize the photofission yield in a depleted-uranium (DU) object in the bremsstrahlung far field by varying the anode-cathode (AK) diode gap spacing and by adding an inner-diameter-reducing insert in the outer conductor wall. An extensive suite of diagnostics was fielded to measure the bremsstrahlung beam and DU fission yield as functions of diode geometry. Delayed fission neutrons from the DU proved to be a valuable diagnostic for measuring bremsstrahlung photons above 5 MeV. The measurements are in broad agreement with particle-in-cell and Monte Carlo simulations of electron dynamics and radiation transport. These show that with increasing AK gap, electron losses to the insert and outer conductor wall increase and that the electron angles impacting the bremsstrahlung converter approach normal incidence. The diode conditions for maximum fission yield occur when the gap is large enough to produce electron angles close to normal, yet small enough to limit electron losses.

  16. Nonexistence of two forms of turbulent bremsstrahlung

    International Nuclear Information System (INIS)

    Kuijpers, J.; Melrose, D.B.

    1985-01-01

    It is shown that the forms of turbulent bremsstrahlung proposed by Tsytovich, Stenflo, and Wilhelmsson and by Nambu do not exist. The proposed mechanisms involve upconversion of ion sound turbulence into Langmuir turbulence, with the ion sound waves being emitted and absorbed resonantly and the Langmuir waves being emitted and absorbed nonresonantly. It is pointed out that a symmetry implicit in a standard QED treatment implies that there is another contribution to turbulent bremsstrahlung in addition to that calculated by Tsytovich, Stenflo, and Wilhelmsson and that the two contributions cancel exactly, leading to the null result. (Our arguments on this point have proved controversial.) Nambu made an approximation inconsistently, and when this approximation is not made, two terms in his analytic treatment cancel exactly. We argue that turbulent bremsstrahlung is related to a radiative correction in which the resonant emission of ion sound turbulence is modified by the nonresonant emission and absorption of Langmuir waves. Physically we interpret the nonexistence of turbulent bremsstrahlung as being due to each emission of a Langmuir quantum being associated with an absorption of an identical Langmuir quantum so that the Langmuir turbulence is unchanged. Proposed astrophysical applications of turbulent bremsstrahlung need to be reconsidered

  17. Resonance double magnetic bremsstrahlung in a strong magnetic field

    International Nuclear Information System (INIS)

    Fomin, P.I.; Kholodov, R.I.

    2003-01-01

    The possibility of resonance double magnetic bremsstrahlung in the approximation of weakly excited electron states in a strong external magnetic field is analyzed. The differential probability of this process in the Breit-Wigner form is obtained. The probability of double magnetic bremsstrahlung (second-order process of perturbation theory) is compared with the probability of magnetic bremsstrahlung (first-order process of perturbation theory)

  18. Neutron-proton bremsstrahlung studies using the white neutron source at the LAMPF/WNR

    International Nuclear Information System (INIS)

    Wender, S.A.; Nelson, R.O.; Schillaci, M.E.; Blann, M.

    1990-01-01

    Nucleon-nucleon bremsstrahlung is a few-body radiative process that provides insight into several areas of nuclear physics. It is one of the simplest systems for studying the off-shell behavior of the nucleon-nucleon potential. The physics involved in neutron-proton bremsstrahlung (NPB) is significantly different from that of proton-proton bremsstrahlung (PPB). In particular, NPB cross sections are much larger than PPB cross sections because NPB allows E1 radiation, and the contribution to the cross section from the meson exchange currents has been calculated to be as large as the contributions from external radiation. To date there have been essentially four NPB experiments. These measurements have covered only a small part of the available phase space. A major experimental problem in performing these measurements has been the lack of a suitable intense, high-energy neutron beam. We are planning a measurement of the NPB cross section using the white neutron source at the WNR target area at the LAMPF accelerator. We plant to implement the experiment in three phases. In this first state, we shall measure inclusive hard-photon production using a multi-element gamma-ray telescope that is insensitive to neutrons. In the second phase, we shall measure the bremsstrahlung gamma-rays in coincidence with recoil protons. In the last phase, we shall detect the scattered neutrons in coincidence with the recoil protons and gamma rays. 8 refs., 6 figs

  19. Polarization of Bremsstrahlung

    International Nuclear Information System (INIS)

    Miller, J.

    1957-01-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [fr

  20. Nuclear critical opalescence and electromagnetic probes

    International Nuclear Information System (INIS)

    Delorme, J.

    1980-01-01

    A description of nuclear critical opalescence is presented with emphasis on the information which can be gained from electromagnetic probes. The connection with standard nuclear physics treatments is given. Experimental possibilities are reviewed. Present information from electron scattering is shown to be unconclusive. The maximum sensitivity to critical phenomena would be attained by measurements of longitudinal spin form factors. Photopion reactions are analyzed in this spirit and found to be promising

  1. Nuclear critical opalescence and electromagnetic probes

    International Nuclear Information System (INIS)

    Delorme, J.

    1981-01-01

    A description of nuclear critical opalescence is presented with emphasis on the information which can be gained from electromagnetic probes. The connection with standard nuclear physics treatments is given. Experimental possibilities are reviewed. Present information from electron scattering is shown to be unconclusive. The maximum sensitivity to critical phenomena would be attained by measurements of longitudinal spin form factors. Photopion reactions are analyzed in this spirit and found to be promising. (orig.)

  2. Bremsstrahlung doses from natural uranium ingots

    International Nuclear Information System (INIS)

    Anderson, J. L.; Hertel, N. E.

    2005-01-01

    In the past, some privately owned commercial facilities in the United States were involved in producing or processing radioactive materials used in the production of atomic weapons. Seven different geometrical objects, representative of the configurations of natural uranium metal potentially encountered by workers at these facilities, are modelled to determine gamma ray and Bremsstrahlung dose rates. The dose rates are calculated using the MCNP5 code and also by using the MICROSHIELD point-kernel code. Both gamma ray and Bremsstrahlung dose rates are calculated and combined to obtain a total dose rate. The two methods were found to be in good agreement despite differences in modelling assumptions and method differences. Computed total dose rates on the surface of these objects ranged from ∼51-84 μSv h -1 and 17-95 μSv h -1 using the MCNP5 and the MICROSHIELD modeling, respectively. The partitioning of the computed dose rates between gamma rays and Bremsstrahlung were the same order of magnitude for each object. (authors)

  3. Bremsstrahlung doses from natural uranium ingots.

    Science.gov (United States)

    Anderson, Jeri L; Hertel, Nolan E

    2005-01-01

    In the past, some privately owned commercial facilities in the United States were involved in producing or processing radioactive materials used in the production of atomic weapons. Seven different geometrical objects, representative of the configurations of natural uranium metal potentially encountered by workers at these facilities, are modelled to determine gamma ray and bremsstrahlung dose rates. The dose rates are calculated using the MCNP5 code and also by using the MICROSHIELD point-kernel code. Both gamma ray and bremsstrahlung dose rates are calculated and combined to obtain a total dose rate. The two methods were found to be in good agreement despite differences in modelling assumptions and method differences. Computed total dose rates on the surface of these objects ranged from approximately 51-84 microSv h(-1) and 17-95 microSv h(-1) using the MCNP5 and the MICROSHIELD modeling, respectively. The partitioning of the computed dose rates between gamma rays and bremsstrahlung were the same order of magnitude for each object.

  4. Nonlinear effects on bremsstrahlung emission in dusty plasmas

    International Nuclear Information System (INIS)

    Kim, Young-Woo; Jung, Young-Dae

    2004-01-01

    Nonlinear effects on the bremsstrahlung process due to ion-dust grain collisions are investigated in dusty plasmas. The nonlinear screened interaction potential is applied to obtain the Fourier coefficients of the force acting on the dust grain. The classical trajectory analysis is applied to obtain the differential bremsstrahlung radiation cross section as a function of the scaled impact parameter, projectile energy, photon energy, and Debye length. The result shows that the nonlinear effects suppress the bremsstrahlung radiation cross section due to collisions of ions with positively charged dust grains. These nonlinear effects decrease with increasing Debye length and temperature, and increase with increasing radiation photon energy

  5. Nuclear reactions as structure probes

    International Nuclear Information System (INIS)

    Fernandez, Bernard; Cugnon, Joseph; Roussel-Chomaz, Patricia; Sparenberg, Jean-Marc; Oliveira Santos, Francois de; Bauge, Eric; Poves, Alfredo; Keeley, Nicholas; Simenel, Cedric; Avez, Benoit; Lacroix, Denis; Baye, Daniel; Cortina-Gil, Dolores; Pons, Alexandre

    2007-09-01

    This publication gathers courses which aim at giving a view on new experiments which are performed by using radioactive beams, notably low intensity beams, in different accelerators, and allow the structure of very exotic nuclei to be characterized. Experimental as well as theoretical aspects are thus addressed. The contributions propose: a brief history of nuclear reactions and of instruments used to study them from the discovery of nucleus to the DWBA (Distorted Wave Born Approximation); an overview of nuclear reactions; experimental techniques; the theory of collisions at low energy; resonant elastic scattering, inelastic scattering and astrophysical reactions; to probe nuclear structure with nucleons; shell model and spectroscopic factors; analysis of transfer reactions and determination of spectroscopic factors; microscopic approaches of nuclear dynamics; theoretical aspects of dissociation reactions; experimental aspects of knockout reactions; research in oenology with the chemical characterisation of defective ageing of dry white wines

  6. Electron-electron collision effects on the bremsstrahlung emission in Lorentzian plasmas

    International Nuclear Information System (INIS)

    Jung, Young-Dae; Kato, Daiji

    2009-01-01

    Electron-electron collision effects on the electron-ion bremsstrahlung process are investigated in Lorentzian plasmas. The effective electron-ion interaction potential is obtained by including the far-field terms caused by electron-electron collisions with an effective Debye length in Lorentzian plasmas. The bremsstrahlung radiation cross section is obtained as a function of the electron energy, photon energy, collision frequency, spectral index and Debye length using the Born approximation for the initial and final states of the projectile electron. It is shown that the non-Maxwellian character suppresses the bremsstrahlung radiation cross section. It is also shown that the electron-electron collision effect enhances the bremsstrahlung emission spectrum. In addition, the bremsstrahlung radiation cross section decreases with an increase in the plasma temperature.

  7. Study of bremsstrahlung photons in bulk target using MCNP code

    Directory of Open Access Journals (Sweden)

    S. Sangaroon

    2017-11-01

    Full Text Available The aim of this research was to study the feasibility of bremsstrahlung photon production in target bombarded by 1 GeV electrons. The calculations were performed by the Monte Carlo code MCNP. Six target materials with densities between 2 and 20 g/cm3 were studied. The bremsstrahlung photon flux is high for the target density above 8 g/cm3. Copper is the best target for 1 GeV electron beam due to high bremsstrahlung photon production, low scattering and low transmission electron flux. The copper target was altered to have different thicknesses between 0.01 and 2.5 cm. The results showed that the bremsstrahlung photon flux significantly increased when the target thickness increased from 0.01 to 1.5 cm. The angular distribution of the bremsstrahlung photons with angles between 0 and 120 degrees was determined for copper target. The maximum angle of the photon scattering was about 20 degree.

  8. The Cherenkov Bremsstrahlung

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.

    1995-01-01

    The vanishing of the 'retardation factor' leads to a significant growth of the intensity of the electromagnetic field 'velocity part' of the moving charge. The Cherenkov radiation is its physical consequence. The same reason also conditions the growth of another term: the 'acceleration part' of the field which gives rise to the 'Cherenkov Bremsstrahlung'. 4 refs

  9. Nuclear probes in physical and geochemical studies of natural diamonds

    International Nuclear Information System (INIS)

    Sellschop, J.P.F.

    In this review the emphasis is directed to the use of nuclear particles for the analysis of impurities in diamond from an interest in both the observed physical properties and genesis of diamond and the inter-relation between these two aspects. However (nuclear) radiation can be used more specifically: from the inter-relation of elemental impurities chemical and geochemical information can be deduced, from energy variation depth distributions of selected impurities can be determined, the prospect of lattice location of impurities exists from the use of extremely finely collimated beams of nuclear particles, which are used also for probing the inter-atomic fields, and finally all nuclear probes excite luminescence in diamonds

  10. Gluon Bremsstrahlung in Weakly-Coupled Plasmas

    International Nuclear Information System (INIS)

    Arnold, Peter

    2009-01-01

    I report on some theoretical progress concerning the calculation of gluon bremsstrahlung for very high energy particles crossing a weakly-coupled quark-gluon plasma. (i) I advertise that two of the several formalisms used to study this problem, the BDMPS-Zakharov formalism and the AMY formalism (the latter used only for infinite, uniform media), can be made equivalent when appropriately formulated. (ii) A standard technique to simplify calculations is to expand in inverse powers of logarithms ln(E/T). I give an example where such expansions are found to work well for ω/T≥10 where ω is the bremsstrahlung gluon energy. (iii) Finally, I report on perturbative calculations of q.

  11. Bremsstrahlung from relativistic bare heavy ions: Nuclear and electronic contributions in amorphous and crystalline materials

    DEFF Research Database (Denmark)

    Jensen, Tue Vissing; Sørensen, Allan Hvidkjær

    2013-01-01

    A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... in a pronounced directional dependence of the energy loss of bare heavy ions at extreme relativistic energies....

  12. Electron and bremsstrahlung penetration and dose calculation

    Science.gov (United States)

    Watts, J. W., Jr.; Burrell, M. O.

    1972-01-01

    Various techniques for the calculation of electron and bremsstrahlung dose deposition are described. Energy deposition, transmission, and reflection coefficients for electrons incident on plane slabs are presented, and methods for their use in electron dose calculations were developed. A method using the straight-ahead approximation was also developed, and the various methods were compared and found to be in good agreement. Both accurate and approximate methods of calculating bremsstrahlung dose were derived and compared. Approximation is found to give a good estimate of dose where the electron spectrum falls off exponentially with energy.

  13. Probing the density content of the nuclear symmetry energy

    Indian Academy of Sciences (India)

    Abstract. The nature of equation of state for the neutron star matter is crucially governed by the density dependence of the nuclear symmetry energy. We attempt to probe the behaviour of the nuclear symmetry energy around the saturation density by exploiting the empirical values for volume and surface symmetry energy ...

  14. Photopion reactions, a probe for nuclear critical opalescence

    International Nuclear Information System (INIS)

    Delorme, J.

    1980-07-01

    It is shown that photopion reactions are a good probe of the nuclear pion field for momenta characteristic of pion condensation. They are thus a direct detector of critical opalescence. Best conditions for experimental detection are discussed

  15. The (n,p) reaction as a probe of nuclear structure

    International Nuclear Information System (INIS)

    Jackson, K.P.; Celler, A.

    1988-08-01

    An account is given of some results of studies of the (n,p) reaction on nuclear targets at TRIUMF. The (n,p) reaction, inducing spin flip transitions in isospin space, appears to exhibit a unique sensitivity to certain aspects of nuclear structure. The TRIUMF facility is the first to exploit the (n,p) reaction as a detailed probe of nuclear structure at energies above 65 MeV. In the (n,p) reaction Fermi transitions are absent, but there is a dramatic impact on Gamow-Teller and other collective transactions. Some nuclear transition matrix elements can be estimated on the basis of (n,p) measurements. Experiments have been carried out at TRIUMF on Li 6 , Fe 5 4, and Zr 9 0 targets. The calibration of the (n,p) reaction as a probe of the Gamow-Teller strength B + GT has been achieved for three targets. (L.L.) (45 refs., 10 figs.)

  16. Quantum-mechanical suppression of bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Becker-Szendy, R.; Keller, L.; Niemi, G.; Perl, M.; Rochester, L. [Stanford Univ., CA (United States); Anthony, P. [Stanford Univ., CA (United States)]|[Lawrence Livermore National Lab., CA (United States); Bosted, P. [American Univ., Washington, DC (United States); Cavalli-Sforza, M.; Kelley, L.; Klein, S. [Univ. of California, Santa Cruz, CA (United States)] [and others

    1994-12-01

    The authors have studied quantum-mechanical suppression of bremsstrahlung of low-energy 1-500 MeV photons from high-energy 25 GeV electrons. They have measured the LPM effect, where multiple scattering of the radiating electron destroys coherence required for the emission of low-energy photons, and the dielectric effect, where the emitted photon traveling in the radiator medium interferes with itself. For the experiment, the collaboration developed a novel method of extracting a parasitic low-intensity high-energy electron beam into the fixed target area during normal SLC operation of the accelerator. The results agree quantitatively with Migdal`s calculation of the LPM effect. Surface effects, for which there is no satisfactory theoretical prediction, are visible at low photon energies. For very thin targets, the suppression disappears, as expected. Preliminary results on dielectric suppression of bremsstrahlung are in qualitative agreement with the expectation.

  17. Detection of tricuspid insufficiency by portable nuclear probe monitoring over the liver

    International Nuclear Information System (INIS)

    Dey, H.M.; Schulman, P.; Smith, V.E.; Karimeddini, M.K.; Spencer, R.P.

    1983-01-01

    A case is presented in which a portable nuclear scintillation probe was used to detect tricuspid regurgitation. An electrocardiographically-gated scintigraphic collection obtained over the liver was correlated with findings from contrast echocardiography and jugular venous pulse tracings. The nuclear probe may provide a simple means for the detection of tricuspid insufficiency. It remains to be determined if quantification of severity will be possible

  18. Diffractive corrections to the muon Bremsstrahlung

    International Nuclear Information System (INIS)

    Kel'ner, S.R.; Fedotov, A.M.

    1999-01-01

    The corrections to the muon Bremsstrahlung cross section due to diffraction of hard photons on nuclei are obtained. In this process the momentum is transmitted to a nucleus not by a charged particle but by the photon the interaction of which with the nucleus can be considered as diffraction on weakly absorbing ball. The amplitude of the process interferes with the usual Bremsstrahlung amplitude, therefore in the cross section together with the diffraction correction the interference term also appears, possessing different sings for μ + and μ - . The photon emission cross section also depends on the sing of muon charge and for muon energy about 10 TeV the difference between the cross section may reach 10%. The corrections to the radiation energy loss are also calculated [ru

  19. Differential bremsstrahlung and pair production cross sections at high energies

    International Nuclear Information System (INIS)

    Olsen, Haakon A.

    2003-01-01

    Detailed differential cross sections for high energy bremsstrahlung and pair production are derived with specific attention to the differences between the two processes, which are considerable. For the integrated cross sections, which are the only cross sections specifically known until now, the final state integration theorem guarantees that the exact cross section formulas can be exchanged between bremsstrahlung and pair production by the same substitution rules as for the Born-approximation Bethe-Heitler cross sections, for any amount of atomic screening. In fact the theorem states that the Coulomb corrections to the integrated bremsstrahlung and pair production cross sections are identical for any amount of screening. The analysis of the basic differential cross sections leads to fundamental physical differences between bremsstrahlung and pair production. Coulomb corrections occur for pair production in the strong electric field of the atom for 'large' momentum transfer of the order of mc. For bremsstrahlung, on the other hand, the Coulomb corrections take place at a 'large' distance from the atom of the order of ((ℎ/2π)/mc)ε, with a 'small' momentum transfer mc/ε, where ε is the initial electron energy in units of mc 2 . And the Coulomb corrections can be large, of the order of larger than (Z/137) 2 , which is considerably larger than the integrated cross section corrections

  20. Ab initio simulation of stimulated bremsstrahlung in an intense laser field

    International Nuclear Information System (INIS)

    Volkova, E.A.; Popov, A.M.; Popovicheva, O.B.

    1992-01-01

    Numerical solution of the time-dependent Schroedinger equation for a quantum system in the field of an electromagnetic wave is used to study a one-dimensional model of stimulated bremsstrahlung (absorption or emission of photons by a field in connection with Coulomb scattering of an electron). The time dependence of the stimulated bremsstrahlung effect is analyzed for various laser radiation intensities. The process of stimulated photorecombination is examined. The results of the calculation are compared with the analytical theory of the stimulated bremsstrahlung effect. 14 refs., 6 figs

  1. Investigation of the influence of nuclear charge on the internal Bremsstrahlung accompanying the β-decay of 45Ca and 141Ce

    International Nuclear Information System (INIS)

    Khalil, E.I.; Basha, A.M.

    1995-01-01

    The internal Bremsstrahlung (IB) spectrum accompanying the allowed β-decay of 141 Ce was measured using NaI (TI) scintillation spectrometer. The corrected IB distribution was compared with the theories for allowed β-transition of Knipp and Uhlenbeck as well as of Bloch (KUB), Lewis and Ford and Nilsson. Further, for 141 Ce isotope the corrected IB distribution was compared with the Ford and Martin theory (for detour β-transition) and modified KUB theory (where the shape correction factor suggested by Konopinski and Uhlenbeck on the Fermi β-decay theory was applied to the calculated IB based on Nilsson theory). This comparison between experiment and theory, and between the measurements of the two isotopes reflects the role played by the nuclear charge and the degree of forbiddenness on the IB spectrum. (author). 26 refs., 5 figs., 1 tab

  2. Measurements of Bremsstrahlung radiation and X-ray heat load to cryostat on SECRAL

    International Nuclear Information System (INIS)

    Zhao, H.Y.; Cao, Y.; Lu, W.; Zhang, W.H.; Zhao, H.W.; Zhang, X.Z.; Zhu, Y.H.; Li, X.X.; Xie, D.Z.

    2012-01-01

    The measurement of Bremsstrahlung radiation from ECR (Electron Cyclotron Resonance) plasma can yield certain information about the ECR heating process and the plasma confinement, and more important it can give a plausible estimate of the X-ray heat load to the cryostat of a superconducting ECR source. To better understand the additional heat load to the cryostat due to Bremsstrahlung radiation, the axial Bremsstrahlung measurements have been conducted on SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) with different source parameters. In addition, the heat load induced by intense X-ray or even γ-ray was estimated in terms of liquid helium consumption. The relationship between these two parameters is presented here. Thick-target Bremsstrahlung, induced by the collision of hot electrons with the wall or the source electrode, is much more intensive compared with the radiation produced in the plasma and, consequently, much more difficult to shield off. In this paper the presence of the thick-target Bremsstrahlung is correlated with the magnetic confinement configuration, specifically, the ratio of B(last) to B(ext). And possible solutions to reduce the X-ray heat load induced by Bremsstrahlung radiation are proposed and discussed. It appears that by choosing an appropriate ratio of B(last) to B(ext) the thick-target Bremsstrahlung radiation can be avoided effectively. The paper is followed by the associated poster

  3. 200-MeV bremsstrahlung tagged photon beams at Sendai

    International Nuclear Information System (INIS)

    Hirose, K.; Chiba, M.; Inoue, M.; Kanda, H.; Kimura, R.; Kino, K.; Kobayashi, Y.; Konno, O.; Maeda, K.; Miyase, H.; Miyamoto, A.; Ohtsuki, T.; Saito, A.; Suda, T.; Takahashi, K.; Tamae, T.; Terasaki, Y.; Terasawa, T.; Tsubota, H.; Tsuruta, T.; Utoyama, M.; Yuuki, H.; Yamaguchi, Y.; Yamazaki, H.

    2006-01-01

    A new beam line for photonuclear reaction experiments using tagged photons has been constructed to take advantage of the completion of the 1.2-GeV STretcher Booster (STB) ring at the Laboratory of Nuclear Science (LNS), Tohoku University. A photon tagging system was installed at the end of the new beam line. It provides bremsstrahlung tagged photon beams in an energy range from 0.2E 0 to 0.8E 0 MeV at the incident electron energy E 0 with an energy resolution of ΔE/E∼10 -2 . The tagged photon intensity I= 6 photons/s is available for typical photonuclear reaction experiments. We introduce the basic parameters of the tagged photons by showing the commissioning data

  4. Bremsstrahlung emission probability in the α decay of 210Po

    International Nuclear Information System (INIS)

    Boie, Hans-Hermann

    2009-01-01

    A high-statistics measurement of bremsstrahlung emitted in the α decay of 210 Po has been performed. The measured differential emission probabilities, which could be followed up to γ-energies of ∝ 500 keV, allow for the first time for a serious test of various model calculations of the bremsstrahlung accompanied α decay. It is shown that corrections to the α-γ angular correlation due to the interference between the electric dipole and quadrupole amplitudes and due to the relativistic character of the process have to be taken into account. With the experimentally derived angular correlation the measured energydifferential bremsstrahlung emission probabilities show excellent agreement with the fully quantum mechanical calculation. (orig.)

  5. Probing nuclear structure with nucleons

    International Nuclear Information System (INIS)

    Bauge, E.

    2007-01-01

    The goal of this lecture is to show how nucleon scattering can be used to probe the structure of target nuclei, and how nucleon scattering observables can be interpreted in terms of nuclear structure using microscopic optical potentials. After a brief overview of the specificities of nucleon-nucleus scattering, and a quick reminder on scattering theory, the main part of this lecture is devoted to the construction of optical potentials in which the target nuclei structure information is folded with an effective interaction. Several examples of such microscopic optical model potentials are given. (author)

  6. Bremsstrahlung in electron-positronium scattering

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Korol, A.V.; Solovyov, A.V.

    1986-01-01

    The spectrum of radiation formed in the fast nonrelativistic electron scattering on positronium is calculated. It is shown that all the radiation proceeds via virtual positronium deformations during the collision. An essential difference of bremsstrahlung spectra in electron on positronium and electron on hydrogen scattering is demonstrated. (orig.)

  7. Cooling effect in emissions of 103mRh excited by bremsstrahlung

    International Nuclear Information System (INIS)

    Cheng, Y; Xia, B; Chen, C P

    2009-01-01

    Nonlinear characteristic emissions of Kα, Kβ and γ with a significant triplet splitting at room temperature are observed from the long-lived nuclear state of 103m Rh excited by bremsstrahlung irradiation. A pronounced phase-transition-like narrowing of the emission profiles occurs immediately after the sample is cooled down to 77 K. The room temperature profiles reappear again abruptly and almost reversibly as the temperature drifts freely back to approximately the ice point after the filling with liquid nitrogen is stopped. These emission properties at 300 K and at low temperature may indicate that the 103m Rh nuclei are in collective states.

  8. Hard photons a probe of the heavy ion collision dynamics

    International Nuclear Information System (INIS)

    Schutz, Y.

    1994-01-01

    Heavy-ion collisions have proven to be a unique tool to study the nucleus in extreme states, with values of energy, spin and isospin far away from those encountered in the nucleus in its ground state. Heavy-ion collisions provide also the only mean to form and study in the laboratory nuclear matter under conditions of density and temperature which could otherwise only be found in stellar objects like neutron stars and super-novae. the goal of such studies is to establish the equation of state of nuclear matter and the method consist in searching the collective behaviour in which heavy-ion collisions differ from a superposition of many nucleon-nucleon collisions. Among the various probes of collective effects, like flow, multifragmentation, or subthreshold particles, we have selected hard photons because they provide, together with dileptons, the only unperturbed probe of a phase of the collision well localized in space and time. The origin of hard photons, defined as the photons building up the spectrum beyond the energy of the giant dipole resonance (E γ > 30∼MeV), is attributed predominantly to the bremsstrahlung radiation emitted incoherently in individual neutron-proton collisions. Their energy reflects the combination of the beam momentum and the momenta induced by the Fermi motion of the nucleons within the collision zone. Therefore, at intermediate energies, hard photons probe the dynamical phase space distribution of participant nucleons and they convey information on the densities reached in heavy-ion collisions, the size and life time of the dense photon source and the compressibility of nuclear matter. The techniques we have developed include intensity interferometry and exclusive measurements scanning with high resolution the whole range of impact parameters. The interpretation of our data is guided by dynamical phase space calculations of the BUU type

  9. Electron collision effects on the bremsstrahlung emission in Lorentzian plasmas

    International Nuclear Information System (INIS)

    Jung, Young-Dae; Kato, Daiji

    2009-06-01

    The electron-electron collision effects on the electron-ion bemsstranhlung process are investigated in warm Lorentzian plasmas. The effective electron-ion interaction potential is obtained by including the far-field terms caused by the electron-electron collisions with the effective Debye length in Lorentzian plasmas. The bremsstranhlung radiation cross section is obtained as a function of the electron energy, photon energy, collision frequency, spectral index, and Debye length using the Born approximation for the initial and final states of the projectile electron. It is shown that the non-Maxwellian character suppresses the bremsstrahlung radiation cross section. It is also shown that the electron-electron collision effect enhances the bremsstrahlung emission spectrum. In addition, the bremsstrahlung radiation cross section decreases with an increase of the plasma temperature. (author)

  10. Dosimetry and microdosimetry using LET spectrometer based on the track-etch detector: radiotherapy bremsstrahlung beam, onboard aircraft radiation field

    Czech Academy of Sciences Publication Activity Database

    Jadrníčková, Iva; Spurný, František

    2006-01-01

    Roč. 41, č. 4 (2006), s. 421-429 ISSN 0033-8451 R&D Projects: GA ČR GA202/04/0795; GA ČR(CZ) GD202/05/H031 Institutional research plan: CEZ:AV0Z10480505 Keywords : linear energy transfer * bremsstrahlung beam * onboard aircraft Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  11. Precision gamma-ray polarimetry applied to studies of bremsstrahlung produced by polarized electrons

    Energy Technology Data Exchange (ETDEWEB)

    Kovtun, Oleksiy

    2015-12-16

    The thesis reports on the measurement of bremsstrahlung linear polarization produced in collisions of longitudinally and transversely polarized electrons with gold atoms. The experiment was performed at the Mainzer Microtron MAMI in the Institut fuer Kernphysik of Johannes Gutenberg-Universitaet Mainz, Germany. Spin-oriented electrons with 2.15 MeV kinetic energy collided with a thin golden target and produced bremsstrahlung. Linear polarization of the emitted photons was measured by means of Compton polarimetry applied to a segmented high-purity germanium detector. Experimental results reveal a strong correlation between the electron spin orientation and bremsstrahlung linear polarization. This indicates a dominant role of the electron spin in atomic-field bremsstrahlung and Coulomb scattering.

  12. Suppression of bremsstrahlung and pair production due to environmental factors

    International Nuclear Information System (INIS)

    Klein, Spencer

    1999-01-01

    The environment in which bremsstrahlung and pair creation occurs can strongly affect cross sections for these processes. Because ultrarelativistic electromagnetic interactions involve very small longitudinal momentum transfers, the reactions occur gradually, spread over long distances. During this time, even relatively weak factors can accumulate enough to disrupt the interaction. In the Landau-Pomeranchuk-Migdal effect, multiple scattering reduces the bremsstrahlung and pair production cross section. This review will discuss this and a variety of other factors that can suppress bremsstrahlung and pair production, as well as related effects involving beamstrahlung and QCD processes. After surveying different theoretical approaches, experimental measurements will be covered. Recent accurate measurements by the SLAC E-146 Collaboration will be highlighted, along with several recent theoretical works relating to the experiment. (c) 1999 The American Physical Society

  13. Comparison of positron emission tomography/CT and bremsstrahlung imaging following Y-90 radiation synovectomy

    International Nuclear Information System (INIS)

    Barber, Thomas W.; Yap, Kenneth S.K.; Cherk, Martin H.; Kalff, Victor; Powell, Anne

    2013-01-01

    The aim of this study is to compare the results of positron emission tomography (PET)/CT with bremsstrahlung imaging following Y-90 radiation synovectomy. All patients referred to our institution for Y-90 radiation synovectomy between July 2011 and February 2012 underwent both PET/CT and bremsstrahlung planar (±single photon emission computed tomography (SPECT) or SPECT/CT) imaging at 4 or 24 h following administration of Y-90 silicate colloid. PET image acquisition was performed for between 15 and 20min. In patients who underwent SPECT, side-by-side comparison with PET was performed and image quality/resolution scored using a five-point scale. The distribution pattern of Y-90 on PET and bremsstrahlung imaging was compared with the intra- or extra-articular location of Y-90 activity on fused PET/CT. Thirteen joints (11 knees and two ankles) were imaged with both PET/CT and planar bremsstrahlung imaging with 12 joints also imaged with bremsstrahlung SPECT. Of the 12 joints imaged with SPECT, PET image quality/resolution was superior in 11 and inferior in one. PET demonstrated a concordant distribution pattern compared with bremsstrahlung imaging in all scans, with the pattern classified as diffuse in 12 and predominantly focal in one. In all 12 diffuse scans, PET/CT confirmed the Y-90 activity to be located intra-articularly. In the one predominantly focal scan, the fused PET/CT images localised the Y-90 activity to mostly lie in the extra-articular space of the knee. PET/CT can provide superior image quality compared with bremsstrahlung imaging and may enable reliable detection of extra-articular Y-90 activity when there are focal patterns on planar bremsstrahlung imaging.

  14. Bremsstrahlung emission probability in the {alpha} decay of {sup 210}Po

    Energy Technology Data Exchange (ETDEWEB)

    Boie, Hans-Hermann

    2009-06-03

    A high-statistics measurement of bremsstrahlung emitted in the {alpha} decay of {sup 210}Po has been performed. The measured differential emission probabilities, which could be followed up to {gamma}-energies of {proportional_to} 500 keV, allow for the first time for a serious test of various model calculations of the bremsstrahlung accompanied {alpha} decay. It is shown that corrections to the {alpha}-{gamma} angular correlation due to the interference between the electric dipole and quadrupole amplitudes and due to the relativistic character of the process have to be taken into account. With the experimentally derived angular correlation the measured energydifferential bremsstrahlung emission probabilities show excellent agreement with the fully quantum mechanical calculation. (orig.)

  15. Multiphoton polarization Bremsstrahlung effect

    International Nuclear Information System (INIS)

    Golovinskij, P.A.

    2001-01-01

    A general approach to induced polarization effects was formulated on the basis of theory of many particles in a strong periodic field. Correlation with the perturbation theory is shown and the types of effective polarization potentials both for isolated atoms and ions, and for ions in plasma, are provided. State of art in the theory of forced polarization Bremsstrahlung effect is analyzed and some outlooks for further experimental and theoretical studies are outlined [ru

  16. Analytical expression for the phantom generated bremsstrahlung background in high energy electron beams

    International Nuclear Information System (INIS)

    Sorcini, B.B.; Hyoedynmaa, S; Brahme, A.

    1995-01-01

    Qualification of the bremsstrahlung photon background generated by an electron beam in a phantom is important for accurate high energy electron beam dosimetry in radiation therapy. An analytical expression has been derived for the background of phantom generated bremsstrahlung photons in plane parallel electron beams normally incident on phantoms of any atomic number between 4 and 92 (Be, C, H 2 O, Al, Cu, Ag, Pb and U). The expression can be used with fairly good accuracy in the energy range between 1 and 50 MeV. The expression is globally based on known scattering power and radiation and collision stopping power data for the phantom material at the mean energy of the incident electrons. The depth dose distribution due to the bremsstrahlung generated in the phantom is derived by folding the bremsstrahlung energy fluence with a simple analytical one-dimensional photon energy deposition kernel. The energy loss of the primary electrons and the generation, attenuation and absorption of bremsstrahlung photons are taken into account in the analytical formula. The photon energy deposition kernel is used to account for the bremsstrahlung produced at one depth that will contribute to the down stream dose. A simple analytical expression for photon energy deposition kernel is consistent with the classical analytical relation describing the photon depth dose distribution. From the surface to the practical range the photon dose increases almost linearly due to accumulation and buildup of the photon produced at different phantom layers. At depths beyond the practical range a simple exponential function can be use to describe the bremsstrahlung attenuation in the phantom. For comparison Monte Carlo calculated distributions using ITS3 Monte Carlo Code were used. Good agreement is found between the analytical expression and Monte Carlo calculation. Deviations of 5% from Monte Carlo calculated bremmstrahlung background are observed for high atomic number materials. The method can

  17. Scintillating fiber array for tagging post-bremsstrahlung electrons

    Science.gov (United States)

    Cole, Philip; Alef, Stefan; Reitz, Björn-Eric; Schmieden, Hartmut; Hannappel, Jürgen; Jude, Thomas; Sandri, Paolo Levi; BGO-OD Collaboration

    2016-03-01

    We seek to extract the kinematic fingerprints of baryon resonances by making use of a high-quality beam of linearly polarized photons at the BGO-OD experiment at ELSA (Bonn, German). We constructed a unique device for precisely determining the degree of polarization in the coherent bremsstrahlung peak. Deflection of post-bremsstrahlung electrons in the magnetic field of the photon tagger provides precise information on the energy and polarization of the bremsstrahlung photons. And thereby will constrain the overall kinematics of the final-state particles in all decay channels of the photoproduced baryon resonances. We designed, prototyped, built, calibrated, and have been operating a three-layered, multi-stranded, scintillating-fiber detector for ensuring the quality of the linearly polarization of the photon beam. The overlapping 2.00-mm scintillating fibers form an array giving ARGUS over 500 channels. The very befitting name harkens to the mythological all-seeing creature Argus Panoptes, the multi-eyed giant. Our work was supported through a Fulbright Scholarship Award and by the Deutsche Forschungsgemeinschaft through the Collaborative Research Center (Sonderforschungsbereich SFB/TR-16) of the universities in Bonn, Giessen and Bochum, Germany. NSF-PHY-1307340.

  18. The role of phantom and treatment head generated bremsstrahlung in high-energy electron beam dosimetry

    International Nuclear Information System (INIS)

    Sorcini, B.B.; Hyoedynmaa, S.; Brahme, A.

    1996-01-01

    An analytical expression has been derived for the phantom generated bremsstrahlung photons in plane-parallel monoenergetic electron beams normally incident on material of any atomic number (Be, H 2 O, Al, Cu and U). The expression is suitable for the energy range from 1 to 50 MeV and it is solely based on known scattering power and radiative and collision stopping power data for the material at the incident electron energy. The depth dose distribution due to the bremsstrahlung generated by the electrons in the phantom is derived by convolving the bremsstrahlung energy fluence produced in the phantom with a simple analytical energy deposition kernel. The kernel accounts for both electrons and photons set in motion by the bremsstrahlung photons. The energy loss by the primary electrons, the build-up of the electron fluence and the generation, attenuation and absorption of bremsstrahlung photons are all taken into account in the analytical formula. The longitudinal energy deposition kernel is derived analytically and it is consistent with both the classical biexponential relation describing the photon depth dose distribution and the exponential attenuation of the primary photons. For comparison Monte Carlo calculated energy deposition distributions using ITS3 code were used. Good agreement was found between the results with the analytical expression and the Monte Carlo calculation. For tissue equivalent materials, the maximum total energy deposition differs by less than 0.2% from Monte Carlo calculated dose distributions. The result can be used to estimate the depth dependence of phantom generated bremsstrahlung in different materials in therapeutic electron beams and the bremsstrahlung production in different electron absorbers such as scattering foils, transmission monitors and photon and electron collimators. By subtracting the phantom generated bremsstrahlung from the total bremsstrahlung background the photon contamination generated in the treatment head can be

  19. CERN: Antiprotons probe the nuclear stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-06-15

    The outer periphery of heavy stable nuclei is notoriously difficult to study experimentally. While the well understood electromagnetic interaction between electrons (or muons) and protons has given the nuclear charge (or proton) distribution with high precision for almost all stable nuclei, neutron distribution studies are much less precise. This is especially true for large nuclear distances, where the nuclear density is small. A few previous experiments probing the nuclear ''stratosphere'' suggested that far from the centre of the nucleus (of the order of 2 nuclear radii) this stratosphere may be composed predominantly of neutrons. At the end of the sixties the term ''neutron halo'' was introduced to describe this phenomenon, but experimental evidence was scarce or even controversial, and remained so for almost a quarter of a century. Recently, the Warsaw/Munich/Berlin collaboration working within the PS203 experiment at CERN's LEAR low energy antiproton ring, proposed a new method to study the nuclear periphery using stopped antiprotons. The halo now looks firmer. A 200 MeV/c beam of antiprotons was slowed down by interactions with atomic electrons. When antiproton kinetic energy drops well below 1 keV, the particles are captured in the outermost orbits of ''exotic atoms'', where the antiprotons take the place of the usual orbital electrons. With the lower orbits in this antiprotonic atom empty, the antiproton drops toward the nuclear surface, first emitting Auger electrons and later predominantly antiprotonic X-rays. Due to the strong interaction between antiprotons and nucleons, the antiproton succumbs to annihilation with a nucleon in the rarified nuclear stratosphere, far above the innermost Bohr orbit of the atom. The annihilation probability in heavy nuclei is maximal where the nuclear density is about 3% of its central value and extends to densities many orders of magnitude smaller. Antiproton annihilation on a proton or on a neutron at the nuclear

  20. Partial decay energy of 51Cr from inner bremsstrahlung spectrum

    International Nuclear Information System (INIS)

    Sanjeeviah, H.; Sanjeevaiah, B.

    1980-01-01

    The inner bremsstrahlung spectrum accompanying orbital electron capture decay of 51 Cr to the first excited state in 51 V was measured in coincidence with 320 keV gamma rays. From the Jauch plot of the spectrum the partial decay energy was deduced to be 433 +- 18 keV in good agreement with the previously measured value and the accepted mass difference. The overall shape factor of the inner bremsstrahlung spectrum was found to be a constant X(1.1 +- 0.1). (author)

  1. An apparatus to study the energy and angular distributions of electron-bremsstrahlung photons from gaseous targets

    International Nuclear Information System (INIS)

    Yadav, Namita; Bhatt, Pragya; Singh, Raj; Singh, B.K.; Quarles, C.A.; Shanker, R.

    2014-01-01

    An apparatus is developed to measure the energy- and angular distributions of bremsstrahlung generated from collisions of energetic electrons with isolated atoms and molecules. A considerable reduction of thick target bremsstrahlung (TTB) background produced by scattered electrons from the chamber wall is achieved. Details of the experimental setup with regard to design of its components, experimental technique, data acquisition and analysis etc. are given and discussed. The reliability and performance of the setup are demonstrated by obtaining some test results on angular- and energy distributions of bremsstrahlung produced in collisions of 4.0 keV electrons with free argon atoms. These results are compared with the theoretical predictions of the ordinary- and the polarization bremsstrahlung emissions. In this comparison, the experimental data for energy distributions of BS photons are found to be in reasonable agreement while they are found to have noticeable differences in shape of angular distributions. - Highlights: • Experimental setup is developed to study DDCS of electron-bremsstrahlung from gaseous targets. • TTB from scattering chamber's wall is reduced appreciably by using a teflon cylinder. • Shape of DDCS of bremsstrahlung compared with the theories shows a satisfactory match. • Angular distributions of bremsstrahlung show anisotropy but still affected by TTB background photons

  2. Zeff from spectroscopic bremsstrahlung measurements at ASDEX Upgrade and JET

    International Nuclear Information System (INIS)

    Meister, H.; Fischer, R.; Horton, L.D.; Maggi, C.F.; Nishijima, D.; Giroud, C.; Zastrow, K.-D.; Zaniol, B.

    2004-01-01

    The effective ionic charge Z eff is a means to assess the impurity content of a fusion plasma. It can be derived from measurements of bremsstrahlung intensity. These have been extended at ASDEX Upgrade by the usage of the sight lines for the charge exchange recombination diagnostic. Together with a previously installed sight line array, it is now possible to routinely determine the bremsstrahlung intensity over the whole minor radius purely from spectroscopic measurements. In a tokamak where the plasma facing components are made up of various materials, this is necessary to check if measurements are contaminated by line radiation. The bremsstrahlung background of the respective spectra is determined using Bayesian probability theory, giving consistent and improved error statistics. Using the information for electron temperature and density profiles, the Z eff profile is determined by an integrated method. The same approach to assess the Z eff profile has been demonstrated to be successful also at the JET tokamak

  3. Probing electron correlation and nuclear dynamics in Momentum Space

    International Nuclear Information System (INIS)

    Deleuze, M S; Hajgato, B; Morini, F; Knippenberg, S

    2010-01-01

    Orbital imaging experiments employing Electron Momentum Spectroscopy are subject to many complications, such as distorted wave effects, conformational mobility in the electronic ground state, ultra-fast nuclear dynamics in the final state, or a dispersion of the ionization intensity over electronically excited (shake-up) configurations of the cation. The purpose of the present contribution is to illustrate how a proper treatment of these complications enables us to probe in momentum space the consequences of electron correlation and nuclear dynamics in neutral and cationic states.

  4. Impact of bremsstrahlung on the neutrinosphere for muon and tau neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Yasin, Hannah; Bartl, Alexander [Institut fuer Kernphysik, TU Darmstadt (Germany); Arcones, Almudena [Institut fuer Kernphysik, TU Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2015-07-01

    Core-collapse supernovae present a challenging and exciting problem that strongly depends on all forces (strong, weak, electromagnetism, and gravity). Neutrinos, although weakly interacting, are key to transporting energy and momentum. Therefore, detailed treatment of neutrino reactions is critical to understand these high energy events. We have studied the impact of different neutrino reactions on the position of the neutrinosphere (i.e., region where neutrinos decouple from matter). Since the density in this region is high the effect of nuclear interactions has to be considered for bremsstrahlung: N+N→N+N+ν+ anti ν. We have employed new, improved approaches to calculate the inverse process and show the effect on the position of the neutrinosphere for muon and tau neutrinos.

  5. Charge-exchange giant resonances as probes of nuclear structure

    International Nuclear Information System (INIS)

    Blomgren, J.

    2001-09-01

    Giant resonances populated in charge-exchange reactions can reveal detailed information about nuclear structure properties, in spite of their apparent featurelessness. The (p,n) and (n,p) reactions - as well as their analog reactions - proceed via the same nuclear matrix element as beta decay. Thereby, they are useful for probing electroweak properties in nuclei, especially for those not accessible to beta decay. The nuclear physics aspects of double beta decay might be investigated in double charge-exchange reactions. detailed nuclear structure information, such as the presence of ground-state correlations, can be revealed via identification of 'first-forbidden' transitions. In addition, astrophysics aspects and halo properties of nuclei have been investigated in charge exchange. Finally, these experiments have questioned our knowledge of the absolute strength of the strong interaction

  6. Bremsstrahlung radiation of a plasma expanding into vacuum

    International Nuclear Information System (INIS)

    Grigor'ev, V.G.; Silakov, V.P.; Fetisov, V.S.

    1978-01-01

    Bremsstrahlung of a flat layer of a dense hot homogeneous plasma expanding to vacuum is considered. The spread of plasma is assumed to be adiabatic, and the plasma density and temperature are considered as known functions of coordinates and time in the radiation transport equation. Formulae for radiation intensity have been obtained in cases when the plasma layer covered by the rarefaction wave are optically thin and optically thick. The dependences of radiation intensity on the parameter α characterizing the optical thickness of the plasma layer and the spectrum of radiation of the spreading layer are presented graphically. It is shown that spread has an essential effect on the heat transfer and the spectral composition of the bremsstrahlung of a dense high-temperature plasma

  7. Probe-holding apparatus for holding a probe for checking steam generator tubes particularly in a nuclear reactor installation

    International Nuclear Information System (INIS)

    Adamowski, A.; Gagny; Gallet, G.; Lhermitte, J.; Monne, M.; Vautherot, G.

    1984-01-01

    Probe-holding apparatus for holding a probe for checking steam generator tubes particularly in a nuclear reactor installation. The apparatus comprises a telescopic arm supported via a ball and socket joint from a support mounted in or near an access aperture in a chamber at one end of the steam generator. A probe guide is carried by a carriage pivotally mounted at the other end of the telescopic arm. The carriage includes an endless belt having a series of spaced projections which engage into the ends of the tubes, the projections being spaced by a distance equal to the tube pitch or a multiple thereof. The belt is driven by a stepping motor in order to move the carriage and place the probe guide opposite different ones of the tubes

  8. CERN: Antiprotons probe the nuclear stratosphere

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The outer periphery of heavy stable nuclei is notoriously difficult to study experimentally. While the well understood electromagnetic interaction between electrons (or muons) and protons has given the nuclear charge (or proton) distribution with high precision for almost all stable nuclei, neutron distribution studies are much less precise. This is especially true for large nuclear distances, where the nuclear density is small. A few previous experiments probing the nuclear ''stratosphere'' suggested that far from the centre of the nucleus (of the order of 2 nuclear radii) this stratosphere may be composed predominantly of neutrons. At the end of the sixties the term ''neutron halo'' was introduced to describe this phenomenon, but experimental evidence was scarce or even controversial, and remained so for almost a quarter of a century. Recently, the Warsaw/Munich/Berlin collaboration working within the PS203 experiment at CERN's LEAR low energy antiproton ring, proposed a new method to study the nuclear periphery using stopped antiprotons. The halo now looks firmer. A 200 MeV/c beam of antiprotons was slowed down by interactions with atomic electrons. When antiproton kinetic energy drops well below 1 keV, the particles are captured in the outermost orbits of ''exotic atoms'', where the antiprotons take the place of the usual orbital electrons. With the lower orbits in this antiprotonic atom empty, the antiproton drops toward the nuclear surface, first emitting Auger electrons and later predominantly antiprotonic X-rays. Due to the strong interaction between antiprotons and nucleons, the antiproton succumbs to annihilation with a nucleon in the rarified nuclear stratosphere, far above the innermost Bohr orbit of the atom. The annihilation probability in heavy nuclei is maximal where the nuclear density is about 3% of its central value and extends to densities many orders of magnitude smaller

  9. Contribution of 210Pb bremsstrahlung to the background of lead shielded gamma spectrometers

    International Nuclear Information System (INIS)

    Mrda, D.; Bikit, I.; Veskovic, M.; Forkapic, S.

    2007-01-01

    Lead, which is often used as a shielding material, contains 210 Pb (T 1/2 =22.3 y). The 46.54 keV γ-intensity of 210 Pb can be easily reduced by an inner lining, but the bremsstrahlung caused by the β-decay of its daughter, 210 Bi, with a maximal electron energy of 1.16 MeV, will contribute to the gamma detector background. The spectrum of this bremsstrahlung is calculated by numerically fitting the β-spectrum and integrating the Koch-Motz formula. The absorption of the bremsstrahlung in the lead and detection efficiencies for the HPGe detector are calculated by the effective solid angle algorithm, using corrections for the photopeak/Compton ratio of cross-sections in Ge. By comparison with the measured background spectrum, it is shown that, for the lead with 25 Bq/kg of 210 Pb up to 500 keV of gamma spectrum, the bremsstrahlung contribution to the background is about 20% for our surface-based detector system. Also, we compared our calculations with a Monte Carlo simulation of another detector system with a shield containing 1 Bq/kg of 210 Pb and found that our analytical method gives a value of roughly two times higher than the Monte Carlo one for the total bremsstrahlung contribution. The quality of the analytical semi-empirical method is proved by the reasonable agreement with the experimental results published

  10. Bremsstrahlung-Based Imaging and Assays of Radioactive, Mixed and Hazardous Waste

    Science.gov (United States)

    Kwofie, J.; Wells, D. P.; Selim, F. A.; Harmon, F.; Duttagupta, S. P.; Jones, J. L.; White, T.; Roney, T.

    2003-08-01

    A new nondestructive accelerator based x-ray fluorescence (AXRF) approach has been developed to identify heavy metals in large-volume samples. Such samples are an important part of the process and waste streams of U.S Department of Energy sites, as well as other industries such as mining and milling. Distributions of heavy metal impurities in these process and waste samples can range from homogeneous to highly inhomogeneous, and non-destructive assays and imaging that can address both are urgently needed. Our approach is based on using high-energy, pulsed bremsstrahlung beams (3-6.5 MeV) from small electron accelerators to produce K-shell atomic fluorescence x-rays. In addition we exploit pair-production, Compton scattering and x-ray transmission measurements from these beams to probe locations of high density and high atomic number. The excellent penetrability of these beams allows assays and images for soil-like samples at least 15 g/cm2 thick, with elemental impurities of atomic number greater than approximately 50. Fluorescence yield of a variety of targets was measured as a function of impurity atomic number, impurity homogeneity, and sample thickness. We report on actual and potential detection limits of heavy metal impurities in a soil matrix for a variety of samples, and on the potential for imaging, using AXRF and these related probes.

  11. Using bremsstrahlung for electron density estimation and correction in EAST tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yingjie, E-mail: bestfaye@gmail.com; Wu, Zhenwei; Gao, Wei; Jie, Yinxian; Zhang, Jizong; Huang, Juan; Zhang, Ling; Zhao, Junyu

    2013-11-15

    Highlights: • The visible bremsstrahlung diagnostic provides a simple and effective tool for electron density estimation in steady state discharges. • This method can make up some disadvantages of present FIR and TS diagnostics in EAST tokamak. • Line averaged electron density has been deduced from central VB signal. The results can also be used for FIR n{sub e} correction. • Typical n{sub e} profiles have been obtained with T{sub e} and reconstructed bremsstrahlung profiles. -- Abstract: In EAST electron density (n{sub e}) is measured by the multi-channel far-infrared (FIR) hydrogen cyanide (HCN) interferometer and Thomson scattering (TS) diagnostics. However, it is difficult to obtain accurate n{sub e} profile for that there are many problems existing in current electron density diagnostics. Since the visible bremsstrahlung (VB) emission coefficient has a strong dependence on electron density, the visible bremsstrahlung measurement system developed to determine the ion effective charge (Z{sub eff}) may also be used for n{sub e} estimation via inverse operations. With assumption that Z{sub eff} has a flat profile and does not change significantly in steady state discharges, line averaged electron density (n{sup ¯}{sub e}) has been deduced from VB signals in L-mode and H-mode discharges in EAST. The results are in good coincidence with n{sup ¯}{sub e} from FIR, which proves that VB measurement is an effective tool for n{sub e} estimation. VB diagnostic is also applied to n{sup ¯}{sub e} correction when FIR n{sup ¯}{sub e} is wrong for the laser phase shift reversal together with noise causes errors when electron density changed rapidly in the H-mode discharges. Typical n{sub e} profiles in L-mode and H-mode phase are also deduced with reconstructed bremsstrahlung profiles.

  12. Measurement of the bremsstrahlung spectra generated from thick ...

    Indian Academy of Sciences (India)

    with those predicted by Monte-Carlo (MC) calculations using PENELOPE code. A close ... done on bremsstrahlung cross-section measurements and many theories have been given for ..... This probability is expected to be maximum for elastic.

  13. Measurement of {sup 27}Al(γ,2pn){sup 24}Na Reaction Cross-sections with 55 -, 60 -, 65 - MeV Bremsstrahlung Employing MCNPX Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. G.; Kye, Y.; Cho, M. H. [POSTECH, Pohang (Korea, Republic of); Namkung, W. [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); KIm, G. N.; Kim, K. [Kyungpook National Univ., Daegu (Korea, Republic of); Lee, M. W.; Kang, Y. R. [Dongnam Inst. Of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-05-15

    Aluminum is used for monitoring the photon flux. The photon flux during the activation can be measured by substituting the {sup 27}Al(γ,2pn){sup 24}Na reaction cross-section induced by bremsstrahlung to reactivity equation. Therefore, if this cross-section is more accurate, gamma-ray flux can be measure more accurately. In this work, the {sup 27}Al(γ,2pn){sup 24}Na reaction cross-sections induced by 55 - 65 MeV bremsstrahlung were measured by activation technique at the Pohang Neutron Facility (PNF) which has produced the nuclear data using Time-Of-Flight method and activation technique. In order to get the photon flux, MCNPX was used. These measurement values were compared with the data of Meyer et al (1968)

  14. 'Atomic Bremsstrahlung': Retrospectives, current status and perspectives

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    2006-01-01

    We describe here the 'Atomic bremsstrahlung' (AB)-emission of continuous spectrum electromagnetic radiation, which is generated in collisions of particles that have internal deformable structure that includes positively and negatively charged constituents. The deformation of one or both colliding partners induces multiple, mainly dipole, time-dependent electrical moments that become a source of radiation. The history of AB invention is presented and its unusual in comparison to ordinary bremsstrahlung (OB) properties, are discussed. As examples, fast electron atom, non-relativistic and relativistic collisions are considered. Attention is given to ion-atom and atom-atom collisions. Specifics of 'elastic' and 'inelastic' (i.e. radiation accompanied by destruction of collision partners) AB will be mentioned. Attention will be given to possible manifestation of AB in nature and in some exotic systems, for instance scattering of electrons upon muonic hydrogen. Some cooperative effects connected to AB will be considered. New classical schemes similar to AB will be presented

  15. Nuclear research with electromagnetic probe. Progress report

    International Nuclear Information System (INIS)

    1990-01-01

    The electromagnetic probe is used to address some of the forefront questions in nuclear physics. Two questions are of special interest in this project, one is related to the electromagnetic properties of the nucleon in the nuclear medium, the other concerns the transition between nucleons-mesons and quarks-gluons degrees of freedom when describing nuclei at medium energies. The electromagnetic properties of free protons have been extensively studied and are used as basic input to describe any of the electric or magnetic properties of nuclei. However, inclusive and semi-exclusive experiments measurements in the quasielastic and the deep inelastic region seem to indicate that the properties of bound nucleons are modified significantly in the nuclear medium. It is therefore of first importance to understand how the free properties of nucleons are modified in order to have a realistic description of nuclei. It was suggested, for example, that nucleons are swollen in nuclei. The physical consequences of such an idea are of great impact on the description of nuclei

  16. The LPM effect in sequential bremsstrahlung: 4-gluon vertices

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Peter; Chang, Han-Chih [Department of Physics, University of Virginia,382 McCormick Road, Charlottesville, Virginia 22904-4714 (United States); Iqbal, Shahin [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad, 45320 (Pakistan)

    2016-10-24

    The splitting processes of bremsstrahlung and pair production in a medium are coherent over large distances in the very high energy limit, which leads to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. In this paper, we continue study of the case when the coherence lengths of two consecutive splitting processes overlap (which is important for understanding corrections to standard treatments of the LPM effect in QCD), avoiding soft-gluon approximations. In particular, this paper completes the calculation of the rate for real double gluon bremsstrahlung from an initial gluon with various simplifying assumptions (thick media; q̂ approximation; and large N{sub c}) by now including processes involving 4-gluon vertices.

  17. The Stonehenge technique. A method for aligning coherent bremsstrahlung radiators

    International Nuclear Information System (INIS)

    Livingston, Ken

    2009-01-01

    This paper describes a technique for the alignment of crystal radiators used to produce high energy, linearly polarized photons via coherent bremsstrahlung scattering at electron beam facilities. In these experiments the crystal is mounted on a goniometer which is used to adjust its orientation relative to the electron beam. The angles and equations which relate the crystal lattice, goniometer and electron beam direction are presented here, and the method of alignment is illustrated with data taken at MAMI (the Mainz microtron). A practical guide to setting up a coherent bremsstrahlung facility and installing new crystals using this technique is also included.

  18. The Stonehenge technique. A method for aligning coherent bremsstrahlung radiators

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, Ken [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)], E-mail: k.livingston@physics.gla.ac.uk

    2009-05-21

    This paper describes a technique for the alignment of crystal radiators used to produce high energy, linearly polarized photons via coherent bremsstrahlung scattering at electron beam facilities. In these experiments the crystal is mounted on a goniometer which is used to adjust its orientation relative to the electron beam. The angles and equations which relate the crystal lattice, goniometer and electron beam direction are presented here, and the method of alignment is illustrated with data taken at MAMI (the Mainz microtron). A practical guide to setting up a coherent bremsstrahlung facility and installing new crystals using this technique is also included.

  19. The Stonehenge technique. A method for aligning coherent bremsstrahlung radiators

    Science.gov (United States)

    Livingston, Ken

    2009-05-01

    This paper describes a technique for the alignment of crystal radiators used to produce high energy, linearly polarized photons via coherent bremsstrahlung scattering at electron beam facilities. In these experiments the crystal is mounted on a goniometer which is used to adjust its orientation relative to the electron beam. The angles and equations which relate the crystal lattice, goniometer and electron beam direction are presented here, and the method of alignment is illustrated with data taken at MAMI (the Mainz microtron). A practical guide to setting up a coherent bremsstrahlung facility and installing new crystals using this technique is also included.

  20. Bremsstrahlung of La and its dependence on electron energy

    International Nuclear Information System (INIS)

    Riehle, F.

    1977-01-01

    Measurements of La-bremsstrahlung isocromates with high resolution for quantum energies between 135 eV and 1867 eV are presented and discussed. In the whole energy range investigated, the isocromate structure, identified with the 4f band of La, is placed 5,45 +- 10,1 eV above the Fermi level. This is in contradiction with a calculation of Gloetzel, which predicts the 4f band maximum about 3eV above the Fermi level. This discrepancy is explained in the present work by the fact that the La electronic density of states depends on the occupation number of the states. The bremsstrahlung isocromate has to be considered as a direct copy of the La ion density of states, consisting of the La-atom and the additional primary electron. Resonance like intensity modulations of the x-ray radiation, resulting from transitions of the primary electron in f-like final states, are observed in an analysis of the La-bremsstrahlung isochromate energy dependence. For transitions of the primary electron in d-like final states, no resonances have been found. The energy dependence of the scattering probability in f-like final states can be explained by a model which assumes the final state as composed by a continuum state and a discrete state. (orig.) [de

  1. Polarization Bremsstrahlung

    CERN Document Server

    Korol, Andrey V

    2014-01-01

    This book introduces and reviews both theory and applications of polarizational bremsstrahlung, i.e. the electromagnetic radiation emitted during collisions of charged particles with structured, thus polarizable targets, such as atoms, molecules and clusters.   The subject, following the first experimental evidence a few decades ago, has gained importance through a number of modern applications.  Thus, the study of several radiative mechanisms is expected to lead to the design of novel light sources, operating in various parts of the electromagnetic spectrum. Conversely, the analysis of the spectral and angular distribution of the photon emission constitutes a new tool for extracting information on the interaction of the colliding particles, and on their internal structure and dynamical properties.   Last but not least, accurate quantitative descriptions of the photon emission processes determine the radiative energy losses of particles in various media, thereby providing essential  information required f...

  2. Multi-probe ionization chamber system for nuclear-generated plasma diagnostics

    International Nuclear Information System (INIS)

    Choi, W.Y.; Ellis, W.H.

    1990-01-01

    This paper reports on the pulsed ionization chamber (PIC) plasma diagnostic system used in studies of nuclear seeded plasma kinetics upgraded to increase the capabilities and extend the range of plasma parameter measurements to higher densities and temperatures. The PIC plasma diagnostic chamber has been provided with additional measurement features in the form of conductivity and Langmuir probes, while the overall experimental system has been fully automated, with computerized control, measurement, data acquisition and analysis by means of IEEE-488 (GPIB) bus control and data transfer protocols using a Macintosh series microcomputer. The design and use of a simple TTL switching system enables remote switching among the various GPIB instruments comprising the multi-probe plasma diagnostic system using software, without the need for a microprocessor. The new system will be used to extend the present study of nuclear generated plasma in He, Ar, Xe, fissionable UF 6 and other fluorine containing gases

  3. Nuclear probes of fundamental symmetries

    International Nuclear Information System (INIS)

    Adelberger, E.G.

    1983-01-01

    Nuclear experiments which probe the parity (P) and time-reversal (T) symmetries and lepton-number conservation are reviewed. The P-violating NN interaction, studied in the NN system and in light nuclei, provides an unique window on ΔS=0 hadronic weak processes. Results are in accord with expectations. Sensitive searches for T-violation via detailed balance, T-odd correlations in γ and β-decay, and a possible neutron electric dipole moment (EDM) are discussed. No T-violation is observed. The EDM limit is almost good enough to eliminate one of the leading theoretical explanations for CP violation. Experimental studies of double β-decay are reviewed. Although ββ nu nu decay has been convincingly detected in geochemical experiments there is no evidence for the lepton number violating ββ decay mode

  4. Neutral bremsstrahlung radiation of Ne, Ar and O

    International Nuclear Information System (INIS)

    Kung, R.T.V.; Chang, C.H.

    1976-01-01

    The neutral Bremsstrahlung cross-sections of Ne, Ar and atomic oxygen around the 3 and 10μ wavelength regions were measured in a high temperature plasma generated in a shock tube. The results were generally a factor of three higher than the theoretical values calculated by Geltman (Geltman, S., JQSRT vol.13, 601 (1973)). Agreement with the experimental results of Taylor and Caledonia (Taylor, R.L. and Caledonia, G., JQSRT vol.9, 657; 681, 1969) around 3μ was good except for the case of Ne. The cross-sections around 10μ are the first measurements in this wavelength region. Enhanced radiation due to atomic line emission on top of the Bremsstrahlung continuum, as predicted by Hyman (Hyman, H.A. and Von Rosenberg, C.W. Jr., JQSRT, vol.15, 919, 1975) was observed around 7.44μ. (author)

  5. On the efficiency calibration of Si(Li) detector in the low-energy region using thick-target bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    An, Z. E-mail: anzhu@scu.edu.cn; Liu, M.T

    2002-10-01

    In this paper, the efficiency calibration of a Si(Li) detector in the low-energy region down to 0.58 keV has been performed using thick-carbon-target bremsstrahlung by 19 keV electron impact. The shape of the efficiency calibration curve was determined from the thick-carbon-target bremsstrahlung spectrum, and the absolute value for the efficiency calibration was obtained from the use of {sup 241}Am radioactive standard source. The modified Wentzel's formula for thick-target bremsstrahlung was employed and it was also compared with the most recently developed theoretical model based upon the doubly differential cross-sections for bremsstrahlung of Kissel, Quarles and Pratt. In the present calculation of theoretical bremsstrahlung, the self-absorption correction and the convolution of detector's response function with the bremsstrahlung spectrum have simultaneously been taken into account. The accuracy for the efficiency calibration in the low-energy region with the method described here was estimated to be about 6%. Moreover, the self-absorption correction calculation based upon the prescription of Wolters et al. has also been presented as an analytical factor with the accuracy of {approx}1%.

  6. Modeling the bremsstrahlung emission from converters

    CERN Document Server

    Mirea, M; Clapier, F; Hassaïne, M; Ibrahim, F; Müller, A C; Pauwels, N; Proust, J; Verney, D; Antoni, R; Bourgeois, L; Kandri-Rody, S

    2001-01-01

    The bremsstrahlung angular and energy theoretical distributions delivered from W and UCx thick converters are reported. This study is focussed on initial kinetic energies of the electron beam included in the range 30-60 MeV, suitable for the production of large radiative yields able to induce the $^{238}$U fission. These results offer the possibility to evaluate the required shielding for a neutron rich nuclei source.

  7. Soft-photon analysis of pion-proton bremsstrahlung

    International Nuclear Information System (INIS)

    Liou, M.K.; Nutt, W.T.

    1977-01-01

    We define the soft-photon approximation consistent in its treatment of both the kinematical and dynamical aspects of bremsstrahlung. Using this consistent soft-photon approximation, we calculate π +- p cross sections and obtain excellent agreement with experiment. Our results suggest that the contributions from off-mass-shell effects and resonances are small

  8. Experimental results on 2-30 keV bremsstrahlung from thick and thin targets

    Energy Technology Data Exchange (ETDEWEB)

    Shanker, R. [Atomic Physics Laboratory, Physics Department, Banaras Hindu University, Varanasi 221005 (India)]. E-mail: rshanker@bhu.ac.in

    2006-10-15

    The recent experimental investigations on electron bremsstrahlung produced from impact of 2-30 keV electrons with thick solid and thin gaseous targets are reviewed. The theoretical models describing the energy and angular distributions of bremsstrahlung photons are discussed with their brief outlines and formulations to explain the experimental data. The results on thick target bremsstrahlung (TTB) spectra produced by keV electrons have suggested that there is a need to develop a comprehensive theory for accounting the solid state effects. It is further noted that the prediction of the modified KKD formula gives a reasonable agreement with the TTB data, whereas a semi-empirical formula gives a better fit to the data for thick targets. The available experimental data for dependence of double differential cross-sections of emitted photons on impact energy and their emission angles for gaseous atoms and molecules exhibit a good agreement with the theoretical calculations of Kissel et al., [1983. Shape functions for atomic-field bremsstrahlung from electrons of kinetic energy 1-500 keV on selected neutral atoms 1

  9. Proton-proton bremsstrahlung towards the elastic limit

    Science.gov (United States)

    Mahjour-Shafiei, M.; Amir-Ahmadi, H. R.; Bacelar, J. C. S.; Castelijns, R.; Ermisch, K.; van Garderen, E.; Gašparić, I.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Kiš, M.; Löhner, H.

    2005-05-01

    In oder to study proton-proton bremsstrahlung moving towards the elastic limit, a detection system, consisting of Plastic-ball and SALAD, was set up and an experiment at 190 MeV incident beam energy was performed. Here, the experimental setup and the data analysis procedure along with some results obtained in the measurement are discussed.

  10. Proton-proton bremsstrahlung towards the elastic limit

    International Nuclear Information System (INIS)

    Mahjour-Shafiei, M.; Amir-Ahmadi, H.R.; Bacelar, J.C.S.; Castelijns, R.; Ermisch, K.; Garderen, E. van; Harakeh, M.N.; Kalantar-Nayestanaki, N.; Kis, M.; Loehner, H.; Gasparic, I.

    2005-01-01

    In oder to study proton-proton bremsstrahlung moving towards the elastic limit, a detection system, consisting of Plastic-ball and SALAD, was set up and an experiment at 190 MeV incident beam energy was performed. Here, the experimental setup and the data analysis procedure along with some results obtained in the measurement are discussed

  11. Comparison of the effect of soft-core potentials and Coulombic potentials on bremsstrahlung during laser matter interaction

    Science.gov (United States)

    Pandit, Rishi R.; Becker, Valerie R.; Barrington, Kasey; Thurston, Jeremy; Ramunno, Lora; Ackad, Edward

    2018-04-01

    An intense, short laser pulse incident on rare-gas clusters can produce nano-plasmas containing energetic electrons. As these electrons undergo scattering, from both phonons and ions, they emit bremsstrahlung radiation. Here, we compare a theory of bremsstrahlung emission appropriate for the interaction of intense lasers with matter using soft-core potentials and Coulombic potentials. A new scaling for the radiation cross-section and the radiated power via bremsstrahlung is derived for a soft-core potential (which depends on the potential depth) and compared with the Coulomb potential. Calculations using the new scaling are performed for electrons in vacuum ultraviolet, infrared and mid-infrared laser pulses. The radiation cross-section and the radiation power via bremsstrahlung are found to increase rapidly with increases in the potential depth of up to around 200 eV and then become mostly saturated for larger depths while remaining constant for the Coulomb potential. In both cases, the radiation cross-section and the radiation power of bremsstrahlung decrease with increases in the laser wavelength. The ratio of the scattering amplitude for the soft-core potential and that for the Coulombic potential decreases exponentially with an increase in momentum transfer. The bremsstrahlung emission by electrons in plasmas may provide a broadband light source for diagnostics.

  12. Application of split field technique with 42 MeV betatron bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Spurny, V; Caha, A; Krystof, V; Ott, O [Vyzkumny Ustav Klinicke a Experimentalni Onkologie, Brno (Czechoslovakia)

    1977-03-01

    The split field technique of external irradiation in oncology is described. A 120x28x79 mm lead shielding block was manufactured for a bremsstrahlung radiation with 42 MeV maximum energy. The block was secured to a holder whose design corresponded to tube holders. The block shielding capacity was tested by phantom measurements at a focal depth of 130 mm and at a distance of the block from the phantom surface of 990 mm. For the 42 MeV bremsstrahlung the reduction was found to be 15% of the focal dose in the 20x20 cm/sup 2/ field in the focal depth at a distance of 1200 mm from the bremsstrahlung focus. Dose distribution was established by using two opposite fields in combination as well as by the courses of the maximum and the relative doses in variation with the female patient's antero-posterior diameter. The results show that the split field technique permits a short adjustment time, is simple and reproducible. As against cobalt application, the beam characteristics permit reducing the integral dose.

  13. Simulation of the Focal Spot of the Accelerator Bremsstrahlung Radiation

    Science.gov (United States)

    Sorokin, V.; Bespalov, V.

    2016-06-01

    Testing of thick-walled objects by bremsstrahlung radiation (BR) is primarily performed via high-energy quanta. The testing parameters are specified by the focal spot size of the high-energy bremsstrahlung radiation. In determining the focal spot size, the high- energy BR portion cannot be experimentally separated from the low-energy BR to use high- energy quanta only. The patterns of BR focal spot formation have been investigated via statistical modeling of the radiation transfer in the target material. The distributions of BR quanta emitted by the target for different energies and emission angles under normal distribution of the accelerated electrons bombarding the target have been obtained, and the ratio of the distribution parameters has been determined.

  14. Bremsstrahlung scattering calculations for the beam stops and collimators in the APS insertion-device beamlines

    International Nuclear Information System (INIS)

    Job, P.K.; Haeffner, D.R.; Shu, D.

    1994-12-01

    Bremsstrahlung is produced in the APS storage ring by the interaction of positrons with the residual gas molecules in the vacuum chamber of the storage ring. The bremsstrahlung production causes a serious challenge in shielding the insertion-device beamlines because the entire straight section (15 meters) is in the line of sight of the beamline. The radiation emerges in a narrow cone tangential to the beam path with the characteristic emission angle 1/γ, where γ is E/mc 2 which is the ratio of the kinetic energy to the rest mass for the positrons. This high-energy gamma radiation has an approximate 1/E spectrum with the maximum energy extending up to the particle energy (7 GeV for the APS). Bremsstrahlung, being high-energy photons, produces an electromagnetic shower when it encounters the beamline elements. A beamline element not thick enough to fully contain an electromagnetic shower can cause considerable scatter of the high-energy bremsstrahlung radiation. The low-energy component of the bremsstrahlung can also be scattered and create high dose rates in the first-optical and white-beam enclosures. The fully developed electromagnetic shower will have a photon spectrum almost independent of the material. The electromagnetic showers in the high-Z materials can also produce photoneutrons. This note reports the summary of EGS4 calculations performed on bremsstrahlung scattering from different beamline components in a typical APS insertion-device beamline. The related recommendations for shielding are also given. The shielding criterion adopted is a total dose rate of 2.5μSv/h (0.25 mrem/h) at 30 cm from the shield

  15. Proton-proton bremsstrahlung in a relativistic covariant model

    NARCIS (Netherlands)

    Martinus, Gerard Henk

    1998-01-01

    Proton-proton bremsstrahlung is one of the simplest processes involving the half off-shell NN interaction. Since protons are equally-charged particles with the same mass, electric-dipole radiation is suppressed and higher-order effects play an important role. Thus it is possible to get information

  16. The bremsstrahlung tagged photon beam in Hall B at JLab

    CERN Document Server

    Sober, D I; Longhi, A; Matthews, S K; O'Brien, J T; Berman, B L; Briscoe, W J; Cole, P L; Connelly, J P; Dodge, W R; Murphy, L Y; Philips, S A; Dugger, M K; Lawrence, D; Ritchie, B G; Smith, E S; Lambert, J M; Anciant, E; Audit, G; Auger, T; Marchand, C; Klusman, M; Napolitano, J; Khandaker, M A; Salgado, C W; Sarty, A J

    2000-01-01

    We describe the design and commissioning of the photon tagging beamline installed in experimental Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This system can tag photon energies over a range from 20% to 95% of the incident electron energy, and is capable of operation with beam energies up to 6.1 GeV. A single dipole magnet is combined with a hodoscope containing two planar arrays of plastic scintillators to detect energy-degraded electrons from a thin bremsstrahlung radiator. The first layer of 384 partially overlapping small scintillators provides photon energy resolution, while the second layer of 61 larger scintillators provides the timing resolution necessary to form a coincidence with the corresponding nuclear interaction triggered by the tagged photon. The definitions of overlap channels in the first counter plane and of geometric correlation between the two planes are determined using digitized time information from the individual counters. Auxiliary beamline devices are briefl...

  17. Production of a narrow band of 0.511-MeV radiation by use of the PHERMEX bremsstrahlung spectrum

    International Nuclear Information System (INIS)

    Stroscio, M.A.

    1976-06-01

    The pair production cross section is numerically integrated over a typical PHERMEX bremsstrahlung spectrum to obtain the probability of pair production in a target of nuclear charge Z, and density rho. The pair production cross section used herein is only approximate in that it neglects screening, neglects the Coulomb field for the emerging pair (first Born approximation), and neglects pair production by atomic electrons. In spite of these approximations, an order-of-magnitude estimate of the amount of 0.511-MeV radiation produced by a typical pulse is still given

  18. Investigation of relativistic laser-plasmas using nuclear diagnostics

    International Nuclear Information System (INIS)

    Guenther, Marc M.

    2011-01-01

    The present work explores with the development of a novel nuclear diagnostic method for the investigation of the electron dynamics in relativistic laser-plasma interactions. An additional aim of this work was the determination of the real laser peak intensity via the interaction of an intense laser short-pulse with a solid target. The nuclear diagnostics is based on a photo-neutron disintegration nuclear activation method. The main constituent of the nuclear diagnostic are novel pseudoalloic activation targets as a kind of calorimeter to measure the high-energy bremsstrahlung produced by relativistic electrons. The targets are composed of several stable isotopes with different (γ,xn)-reaction thresholds. The activated nuclides were identified via the characteristic gamma-ray decay spectrum by using high-resolution gamma spectroscopy after the laser irradiation. Via the gamma spectroscopy the (γ,xn)-reaction yields were determined. The high-energy bremsstrahlung spectrum has been deconvolved using a novel analysis method based on a modified Penfold-Leiss method. This facilitates the reconstruction of the spectrum of bremsstrahlung photons without any anticipated fit procedures. Furthermore, the characterization of the corresponding bremsstrahlung electrons in the interaction zone is accessible immediately. The consolidated findings about the properties of the relativistic electrons were used to determine the real peak intensity at the laser-plasma interaction zone. In the context of this work, experiments were performed at three different laser facilities. First Experiments were carried out at the 100 TW laser facility at Laboratoire pour l'Utilisation des Lasers Intense (LULI) in France and supplementary at the Vulcan laser facility at Rutherford Appleton Laboratory (RAL) in United Kingdom. The main part of the activation experiments were performed at the PHELIX laser facility (Petawatt High Energy Laser for heavy Ion EXperiments) at GSI-Helmholtzzentrum fuer

  19. Stabilization effect of Weibel modes due to inverse bremsstrahlung ...

    Indian Academy of Sciences (India)

    2016-11-04

    Nov 4, 2016 ... In this work, the Weibel instability due to inverse bremsstrahlung absorption in laser fusion plasma ... pling of self-generated magnetic field with the laser wave field. This is ... To describe fully ionized plasma where the interac-.

  20. Electron-positron pair production and bremsstrahlung at intermediate energies in the field of heavy atoms

    International Nuclear Information System (INIS)

    Lee, R.N.; Milstein, A.I.; Strakhovenko, V.M.; Schwartz, O.Ya.

    2006-01-01

    The Coulomb corrections (CC) to the processes of bremsstrahlung and pair production are investigated. The next-to-leading term in the high-energy asymptotics is found. This term becomes very essential in the region of intermediate energies. The influence of screening for CC is small for differential cross section, spectrum, and the total cross section of pair production. The same is true for the spectrum of bremsstrahlung, but not for the differential cross section, where the influence of screening can be very large. The corresponding screening corrections as well as the modification of the differential cross section of bremsstrahlung are found. A comparison of our results for the total cross section of pair production with the experimental data available is performed. This comparison has justified our analytical results and allowed to elaborate a simple ansatz for the next-to-leading correction. The influence of the electron beam shape on CC for bremsstrahlung is investigated. It turns out that the differential cross section is very sensitive to this shape

  1. Bremsstrahlung parameters of praseodymium-142 in different human tissues. A dosimetric perspective for 142Pr radionuclide therapy

    International Nuclear Information System (INIS)

    Bakht, M.K.; Jabal-Ameli, H.; Ahmadi, S.J.; Sadeghi, M.; Sadjadi, S.; Tenreiro, Claudio

    2012-01-01

    Praseodymium-142 [T 1/2 =19.12 h, E β -=2.162 MeV (96.3%), E γ =1575 keV (3.7%)] is one of the 141 Pr radioisotopes. Many studies have been attempted to assess the significance of usage 142 Pr in radionuclide therapy. In many studies, the dosimetric parameters of 142 Pr sources were calculated by modeling 142 Pr sources in the water phantom and scoring the energy deposited around it. However, the medical dosimetry calculations in water phantom consider Bremsstrahlung production, raising the question: ''How important is to simulate human tissues instead of using water phantom?'' This study answers these questions by estimation of 142 Pr Bremsstrahlung parameters. The Bremsstrahlung parameters of 142 Pr as therapeutic beta nuclides in different human tissues (adipose, blood, brain, breast, cell nucleus, eye lens, gastrointestinal tract, heart, kidney, liver, lung deflated, lymph, muscle, ovary, pancreas, cartilage, red marrow, spongiosa, yellow marrow, skin, spleen, testis, thyroid and different skeleton bones) were calculated by extending the national council for radiation protection model. The specific Bremsstrahlung constant (Γ Br ), probability of energy loss by beta during Bremsstrahlung emission (P Br ) and Bremsstrahlung activity (A release ) Br were estimated. It should be mentioned that Monte Carlo simulation was used for estimation of 142 Pr Bremsstrahlung activity based on the element compositions of different human tissues and the calculated exposures from the anthropomorphic phantoms. Γ Br for yellow marrow was smallest amount (1.1962 x 10 -3 C/kg-cm 2 /MBq-h) compared to the other tissues and highest for cortical bone (2.4764 x 10 -3 C/kg-cm 2 /MBq-h), and, overall, Γ Br for skeletal tissues were greater than other tissues. In addition, Γ Br breast was 1.8261 x 10 -3 C/kg-cm 2 /MBq-h which was greater than sacrum and spongiosa bones. Moreover, according to (A release ) Br of 142 Pr, the patients receiving 142 Pr do not have to be hospitalized for

  2. High-resolution x-ray spectroscopy of coherent bremsstrahlung fine structure

    International Nuclear Information System (INIS)

    Lund, M.W.

    1989-01-01

    The aim of this research was to provide experimental evidence for fine structure due to umklapp by distinct reciprocal lattice vectors in coherent bremsstrahlung spectra. The spontaneous emission of photons by relativistic electrons transversing thin crystals is made possible by recoil of the crystal, which absorbs momentum in multiples of ℎG where G is a reciprocal lattice vector. Previous work in the MeV-GeV beam energy range used detectors whose energy resolution was greater than 10%. By fitting a Johann wavelength dispersive spectrometer to a transmission electron microscope the author obtained coherent bremsstrahlung spectra of very high quality with energy resolution of 1%. Important to this result were also the fine angular collimation, small energy width of the electron beam in the microscope, and the accurate control of crystal orientation possible in a modern goniometer stage. The theory of the design of bent crystal x-ray spectrometers is extended to include effects of defocus and aberrations. The theory for diffraction from a stationary three dimensional grating due to a dipole radiator moving at relativistic speeds is derived as well as several other broadening mechanisms stemming from experimental variables. This dissertation provides the first experimental observations and corresponding theoretical background for the fine structure of coherent bremsstrahlung due to umklapp by different G-vectors in the same reciprocal lattice plane

  3. Sealed magic angle spinning nuclear magnetic resonance probe and process for spectroscopy of hazardous samples

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.

    2016-06-14

    A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.

  4. Effective source size, yield and beam profile from multi-layered bremsstrahlung targets

    International Nuclear Information System (INIS)

    Svensson, R.; Brahme, A.

    1996-01-01

    Modern conformal radiotherapy benefits from heterogeneous dose delivery using scanned narrow bremsstrahlung beams of high energy in combination with dynamic double focused multi-leaf collimation and purging magnets. When using a purging magnet to remove electrons and positrons the target space is limited and unorthodox thin multi-layered targets are needed. A computational technique has therefore been developed to determine the forward yield and the angular distributions of the bremsstrahlung beam as well as the size and location of the effective and the virtual photon point source for arbitrary multi-layer bremsstrahlung targets. The Gaussian approximation of the diffusion equation for the electrons has been used and convolved with the bremsstrahlung production process. For electrons with arbitrary emittance impinging on targets of any multi-layer and atomic number combination, the model is well applicable, at least for energies in the range 1-100 MeV. The intrinsic bremsstrahlung photon profile has been determined accurately by deconvolving the electron multiple scattering process from thin experimental beryllium target profiles. For electron pencil beams incident on a target of high density and atomic number such as tungsten, the size of the effective photon source stays at around a tenth of a millimetre. The effective photon source for low-Z materials such as Be, C and Al is located at depths from 3-7 mm in the target, decreasing with increasing atomic number. The effective photon source at off-axis positions then moves out considerably from the central axis, which should be considered when aligning collimators. For high-Z materials such as tungsten, the location of the effective photon source is at a few tenths of a millimetre deep. The virtual photon point source is located only a few tenths of a millimetre upstream of the effective photon source both for high- and low-Z materials. For 50 MeV electrons incident on multi-layered full range targets the radial

  5. Study on the feasibilities of nondestructive testing based on bremsstrahlung albedo

    International Nuclear Information System (INIS)

    Zhalsaraev, B.Zh.; Meshcheryakov, R.P.

    1980-01-01

    Presented are the results of experimental studies of the characteristics of gamma radiation reflected from homogeneous and laminated targets irradiated by 15 MeV betatron bremsstrahlung. Considered are the possibilities of simultaneous testing of thickness and of effective atomic number of materials, identification of heterogeneity of their structure, determination of the parameters of the media which are concealed by the layers of light substances of considerable thickness. The results obtained testify the usability of bremsstrahlung backscattering for contactless or remote control and differentiation of various media and objects, for the analysis and prospecting of surface ore manifestation and for processing control at the concentrating mills as well. The efficiency of the above method is underlined

  6. Use the nuclear code MCNP4X in the study of the behavior of nuclear probe in soils with variation of Mg, Ca, Fe

    International Nuclear Information System (INIS)

    Braga, Mario R.M.S.S.; Oliveira, Arno H.; Lima, Claubia P.B.

    2013-01-01

    The aim of this work is to evaluate the behavior of the variation the elements: Mg, Ca, Fe in the soils composition on a nuclear probe to measure the density of porous materials nondestructive in testing based on coherent Compton Effect, the effect Rayleigh. To study the effect of composition in soil was used nuclear code MCNP4X where was simulated two sources, a source 14mCi americium-241 and other source 4mCi cesium-137, lead shielding and volume scintillator. To avoid problems with geometries were simulated spheres with 1.00 meters of diameter filled with soil to be evaluated. Data analysis allowed establishing correction parameters for nuclear probe. (author)

  7. New knowledge about the bremsstrahlung image of strontium-89 with the scintillation camera

    International Nuclear Information System (INIS)

    Narita, Hiroto; Hirase, Kiyoshi; Uchiyama, Mayuki; Fukushi, Masahiro

    2012-01-01

    Strontium-89 ( 89 Sr) chloride has been used to treat metastases in bone. A method to visualize the distribution of 89 Sr chloride with a scintillation camera was developed in 1996. Studies using bremsstrahlung imaging have shown that 89 Sr accumulates in bone and that the bremsstrahlung generated from biological tissue surrounding bone does not exceed 30 keV. However, it was not clear how low-energy bremsstrahlung from bone can produce peak energy levels of around 75 keV. We speculate that a different (unidentified) factor is involved. The energy spectrum of an 89 Sr source was acquired with a scintillation camera with or without a low-to-medium-energy general-purpose collimator. The energy window was set at 20-650 keV for 4 windows. A 50-mm thick acrylic block was placed between the scintillation camera and the 89 Sr source to exclude the effects of bremsstrahlung. The energy spectrum of 89 Sr covered with lead was acquired using the scintillation camera without a collimator. With the collimator the energy spectrum curve was similar to that without the 50 mm of acrylic. The energy spectrum curve showed peaks at about 75, 170, and 520 keV. Without the collimator the energy spectrum showed a similar curve but no peak at 75 keV peak. The curve was similar to that obtained with the scintillation camera and the collimator; however, the curve obtained when the 89 Sr source had been placed in a lead container was similar to that obtained when the source was unshielded, and the collimator was not attached to the scintillation camera. If bremsstrahlung of 89 Sr produces an image, a low-energy spectrum region should decrease when acrylic is placed between the 89 Sr source and the scintillation camera. However, similar curves were obtained both with the acrylic in place and without the acrylic. Therefore, we believe that the radiation detected by the scintillation camera was not bremsstrahlung due to the beta rays of 89 Sr. Most 89 Sr preparations are contaminated by 85 Sr

  8. Modeling Relativistic Electron Precipitation Bremsstrahlung X-Ray Intensities at 10-100 km Manned Vehicle Altitudes

    Science.gov (United States)

    Krause, L. Habsh; Gilchrist, B. E.; Nishikawa, Ken-Ichi

    2013-01-01

    Relativisitic electron precipitation (REP) events occur when beams or bunches of relativistic electrons of magnetospheric origin enter the Earth's atmosphere, typically at auroral latitudes. REP events are associated with a variety of space weather effects, including production of transitional and bremsstrahlung radiation, catalytic depletion of stratospheric ozone, and scintillation of transionospheric radio waves. This study examines the intensities of x-rays produced at airliner, manned balloon, and space reuseable launch vehicles (sRLVs). The monoenergetic beam is modeled in cylindrical symetry using the paraxial ray equation. Bremsstrahlung photon production is calculated using the traditional Sauter-Elwert cross-section, providing x-ray emission spectra differential in energy and angle. Attenuation is computed for a plane-stratified standard atmosphere, and the loss processes include photoionization, Rayleigh and Compton scattering, electron-positron pair production, and photonuclear interaction. Peak altitudes of electron energy deposition and bremsstrahlung x-ray production were calculated for beams of energies from 1 MeV through 100 MeV. The altitude peak of bremsstrahlung deposition was consistently and significantly lower that that of the electron deposition due to the longer mean free paths of x-rays compared to electrons within the atmosphere. For example, for a nadir-directed monoenergetic 5 MeV beam, the peak deposition altitude was calculated to be 42 km, but the resulting bremsstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.

  9. Fission and nuclear fragmentation of silver and bromine nuclei by photons of 1-6 GeV

    International Nuclear Information System (INIS)

    Pinheiro Filho, J.D.

    1983-01-01

    The studies of fission and fragmentation of silver and bromine nuclei by Bremsstrahlung photons of 1.6 GeV energy range are presented. The Il ford-KO nuclear emulsion submitted to Bremsstrahlung beams in Deutsches Elektronen Synchrotron (DESY) with total doses of 10'' equivalent photons, was used for nuclear fragment detection. The discrimination of fission and fragmentation events was done analysing angular distribution, range and angles between fragments. The results of fragment range distributions, angular distributions, distributions of angles between fragments, distributions of ratio between range, velocity distributions forward/backward ratio, cross sections of fission and fragmentation, nuclear fissionability and ternary fission frequency are presented and discussed. (M.C.K.)

  10. 'Atomic Bremsstrahlung': Retrospectives, current status and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel) and Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation)]. E-mail: Amusia@vms.huji.ac.il

    2006-10-15

    We describe here the 'Atomic bremsstrahlung' (AB)-emission of continuous spectrum electromagnetic radiation, which is generated in collisions of particles that have internal deformable structure that includes positively and negatively charged constituents. The deformation of one or both colliding partners induces multiple, mainly dipole, time-dependent electrical moments that become a source of radiation. The history of AB invention is presented and its unusual in comparison to ordinary bremsstrahlung (OB) properties, are discussed. As examples, fast electron atom, non-relativistic and relativistic collisions are considered. Attention is given to ion-atom and atom-atom collisions. Specifics of 'elastic' and 'inelastic' (i.e. radiation accompanied by destruction of collision partners) AB will be mentioned. Attention will be given to possible manifestation of AB in nature and in some exotic systems, for instance scattering of electrons upon muonic hydrogen. Some cooperative effects connected to AB will be considered. New classical schemes similar to AB will be presented.

  11. Monitoring of energetic characteristics of electron beams during formation of high-power pulsed bremsstrahlung

    International Nuclear Information System (INIS)

    Ivaschenko, D.M.; Mordasov, N.G.; Chlenov, A.M.

    2005-01-01

    A method and a device for monitoring the dynamic and integrated characteristics of high-power electron and bremsstrahlung beams of the pulse accelerators are proposed. The transfer functions for various types of a target in operating conditions of the pulse accelerator UIN-10 are presented. Possibilities if the integrated diagnostics of acceleration rate of the electron beams with simultaneous testing of the bremsstrahlung parameters as a local field point beyond the converting target are shown [ru

  12. Production of a narrow band of 0. 511-MeV radiation by use of the PHERMEX bremsstrahlung spectrum. [Cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Stroscio, M.A.

    1976-06-01

    The pair production cross section is numerically integrated over a typical PHERMEX bremsstrahlung spectrum to obtain the probability of pair production in a target of nuclear charge Z, and density rho. The pair production cross section used herein is only approximate in that it neglects screening, neglects the Coulomb field for the emerging pair (first Born approximation), and neglects pair production by atomic electrons. In spite of these approximations, an order-of-magnitude estimate of the amount of 0.511-MeV radiation produced by a typical pulse is still given.

  13. Soft electromagnetic bremsstrahlung in inelastic hadronic collisions at high and intermediate energies

    International Nuclear Information System (INIS)

    Rueckl, R.

    1978-01-01

    Electromagnetic bremsstrahlung in hadronic collisions was studied extensively at low and intermediate energies. It was found that the infrared divergent term of the cross section describes the data well up to surprisingly large photon energies. Using essentially the same soft photon approximation, production of low mass-low energy electron pairs via internal conversion of soft virtual bremsstrahlung accompanying the production of charged hadrons in hadron-hadron collisions at very high and intermediate energies. The resulting electron yields explain, at least in part, the direct electrons with small transverse momenta seen at the ISR, and are in no contradiction to the rates observed at LAMPF

  14. The bremsstrahlung induced by 0.3-2 keV electron scattering by Ar atoms

    International Nuclear Information System (INIS)

    Gnatchenko, E.V.; Tkachenko, A.A.; Verkhovtseva, E.T.

    2002-01-01

    The differential spectra of a bremsstrahlung resulting from a 0.3-2 keV electron scattering by Ar atoms are studied. Photon energies within the ultrasoft X-ray band from 124 to 190.8 eV, which is characterized by the low dynamic polarizability of the Ar atom, are considered. For the entire spectrum of photon energies (124-190.8 eV), the intensity of the bremsstrahlung differential spectra first grows with an increase in the electron energy from 0.3 to 0.7 keV and then decreases as the electron energy increases from 0.7 to 2 keV. The increase in intensity is directly proportional, and the decrease is inversely proportional to the square root of the energy of the scattered electrons. Within the context of a 'low-energy' approximation, the increase in the number of photons with the electron energy is due to the contribution of the atomic excitation and ionization channels being available during the bremsstrahlung process

  15. Practice for dosimetry in electron and bremsstrahlung irradiation facilities for food processing. 2. ed.

    International Nuclear Information System (INIS)

    2002-01-01

    This practice describes dosimetric procedures to be followed in facility characterization, process qualification, and routine processing for electron beam and bremsstrahlung irradiation facilities for food processing to ensure that product receives an acceptable range of absorbed doses. Other procedures related to facility characterization, process qualification, and routine product processing that may influence and be used to monitor absorbed dose in the product are also discussed. Information about effective or regulatory dose limits for food products is not within the scope of this practice (see ASTM Guides F 1355 and F 1356). The electron energy range covered in this practice is from 0.3 MeV to 10 MeV. Such electrons can be generated in continuous or pulse modes. The maximum electron energy of bremsstrahlung facilities covered in this practice is 10 MeV. A photon beam can be generated by inserting a bremsstrahlung converter in the electron beam path (See ISO/ASTM Practice 51608

  16. Bremsstrahlung of fast electrons in long air gaps

    Energy Technology Data Exchange (ETDEWEB)

    Oreshkin, E. V.; Barengolts, S. A. [P. N. Lebedev Physical Institute, RAS, 119991 Moscow (Russian Federation); General Physics Institute, RAS, 119991 Moscow (Russian Federation); Chaikovsky, S. A. [P. N. Lebedev Physical Institute, RAS, 119991 Moscow (Russian Federation); Institute of High Current Electronics, SB RAS, 634055 Tomsk (Russian Federation); Oginov, A. V.; Shpakov, K. V.; Bogachenkov, V. A. [P. N. Lebedev Physical Institute, RAS, 119991 Moscow (Russian Federation)

    2012-01-15

    The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns have been analyzed. In the experiment, a radiation pulse of photon energy >5 keV and duration 10-20 ns was observed. In analyzing the experimental data it was supposed that a streamer is a plasma protrusion whose surface is equipotential to the cathode surface. It has been shown that the x-ray pulse results from the switch of electrons into the mode of ''runaway'' from the head of anode-directed streamers. For the electrons injected in the electrode gap from the streamer head, conditions for their switching into the mode of continuous acceleration are realized due to the enhanced electric field at the head. The predicted maximum of the spectrum of the bremsstrahlung generated by the runaway electron beam is around 15 keV. The presence of a maximum in the bremsstrahlung spectrum is due to that the photons emitted by electrons are absorbed by atoms of the gas in which the discharge operate.

  17. Electron bremsstrahlung spectrum, 1--500 keV

    International Nuclear Information System (INIS)

    Lee, C.M.; Kissel, L.; Pratt, R.H.; Tseng, H.K.

    1976-01-01

    Numerical data are obtained for the electron bremsstrahlung energy spectrum resulting from incident electrons of kinetic energy 1--500 keV, under the assumption that the process is described as a single-electron transition in a relativistic self-consistent screened potential, using partial-wave expansions. Comparisons with simpler analytical approximations show that these are at best of qualitative validity in this energy range. Our data are used to construct more complete tables of the spectrum by interpolation

  18. Infrared phenomena in quantum electrodynamics : II. Bremsstrahlung and compton scattering

    NARCIS (Netherlands)

    Haeringen, W. van

    The infrared aspects of quantum electrodynamics are discussed by treating two examples of scattering processes, bremsstrahlung and Compton scattering. As in the previous paper one uses a non-covariant diagram technique which gives very clear insight in the cancelling of infrared divergences between

  19. Assembler absolute forward thick-target bremsstrahlung spectra program

    International Nuclear Information System (INIS)

    Niculescu, V.I.R.; Baciu, G.; Ionescu-Bujor, M.

    1981-12-01

    The program is intended to compute the absolute forward thick-target bremsstrahlung spectrum for electrons in the energy range 1-24 MeV. The program takes into account the following phenomena: multiple scattering, energy loss and the attenuation of the emitted gamma rays. The computer program is written in Assembler having a higher degree of generality and is more performant than the FORTRAN version. (authors)

  20. A microcomputerized system of nuclear probe for left ventricular function evaluation

    International Nuclear Information System (INIS)

    Piva, R.M.V.

    1987-01-01

    In this work, it is presented the development of a system, consisting in a nuclear probe and a 16 bits microcomputer, for left ventricular function (LVF) monitoring and analysis. Previously used in renal and thyroid studies, the nuclear probe, 2''x2''NaI(Tl) crystal, was adapted for its new application. The alterations include the design and construction of appropriate colimators and unterfacing to a strip-chart register and a magnetic tape recorder. After a single injection of Tc-99m labelling red blood cells, the probe is placed over the patient's chest on a convenient left anterior oblique position and a left ventricle time activity curve is obtained. This curve and the patient's eletrocardiogram (ECG) are recorded for posterior processing. The software, in PASCAL language, transfers the data from the magnetic tape to the microcomputer and provides the LVF and ECG curves to be displayed on beat-to-beat mode or as mean curves. From these curves one can extract ventricular parameter such as: ejection fraction, ejection rate, systolic and diastolic intervals and heart rate, by manually positioning three cursors on the points of interest. A critical evaluation of this method is performed and its advantages as well as its limitations are discussed. This approach provides an easy to operate and a low cost device that can be useful in many clinical situations, for example, the continuous monitoring in ICUs, the screening in out-patient departments. The assessment of drugs effects on left ventricular function is also possible. (author) [pt

  1. Fission of intermediate mass nuclei by bremsstrahlung photons in the energy range 0.8-1.8 GeV

    International Nuclear Information System (INIS)

    Lima, D.A. de.

    1983-01-01

    The fission of intermediate mass nuclei in the Al-Ta internal induced by bremsstrahlung photons of maximum energies between 0,8 to 1,8 GeV is studied. Thin targets of Nd and Sm and dense targets of Al,Ti,Co,Zr,Nb,Ag,In and Ta are utilized, and all the aspects related with the fission fragment absorption by the targets themselves are considered. The samples are exposed in th 2,5 GeV Electron Synchrotron at Bonn University. Muscovite mica, CR-39 and makrofol are used as fission fragments detectors. Fission cross sections and nuclear fissionabilities of the studied elements are estimated. (L.C.) [pt

  2. Revisiting Bremsstrahlung emission associated with Light Dark Matter annihilations

    CERN Document Server

    Böhm, C

    2006-01-01

    We compute the single bremsstrahlung emission associated with the pair annihilation of spin-0 particles into electrons and positrons, via the t-channel exchange of a heavy fermion. We compare our result with the work of Beacom et al. . Unlike what is stated in the literature, we show that the Bremsstrahlung cross section is not necessarily given by the tree-level annihilation cross section (for a generalized kinematics) times a factor related to the emission of a soft photon. Such a factorization appears only in the soft photon limit or in the approximation where the masses of the particles in the initial and final states are negligible with respect to the mass of the internal particle. However, in the latter case, we do not recover the same factor as for e^+ e- --> mu^+ mu^- gamma. Numerically the difference, in the hard photon limit, is as large as a factor 3.6. However the effect on the upper limit of the dark matter mass is not significant. Using gamma ray observations, we obtain an upper limit on the dar...

  3. Evaluating the therapeutic effect of 89Sr using Bremsstrahlung imaging in patients with bone metastases

    International Nuclear Information System (INIS)

    Zhang Daping; Lou Cen; Chen Liang; Yu Linliang; Huang Huacheng

    2003-01-01

    Objective: To evaluate the therapeutic effect of 89 Sr (a pure beta emitter) using Bremsstrahlung imaging in patients with multiple bone metastases. Methods: 89 Sr Bremsstrahlung imaging was performed 1-2 weeks after injection in 14 patients with bone metastases, using GE Camstar 3200 SPECT equipped with a medium-energy collimator. To improve resolution of imaging, authors selected suitable energy level and wide window width (a 95-100% energy window around 100 KeV). Results: Abnormal uptake was seen in all and was consistent with the results of 99m Tc-MDP imaging. According to this result, authors can realize localization, retention and metabolism of 89 Sr in body. Conclusion: Bremsstrahlung imaging is useful for clinical observation and estimating the curative effect and prognosis in pure beta emitter therapy such as 89 Sr. In addition, it can be helpful in determining dose of 89 Sr if a repeated therapy is needed

  4. Total bremsstrahlung spectra of thick lead compounds produced by {sup 90}Sr beta emitter in photon energy region of 10–100 keV

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Suhansar Jit [Department of Physics, B.B.S.B Polytechnic, Fatehgarh Sahib, Punjab (India); Singh, Tajinder, E-mail: tajindersingh2k9@gmail.com [Department of Physics, Mata Gujri College, Fatehgarh Sahib, Punjab (India); Singh, Doordarshi [Department of Mechanical Engineering, B.B.S.B Engineering College, Fatehgarh Sahib, Punjab (India); Singh, Amrit [Department of Physics, Baba Ajay Singh Khalsa College, Gurdas Nangal, Gurdaspur, Punjab (India); Dhaliwal, A.S. [Department of Physics, Sant Longowal Institute of Engineering & Technology, Longowal (Sangrur), Punjab (India)

    2017-06-15

    Highlights: • Total bremsstrahlung spectra in thick targets of Pb compounds by {sup 90}Sr in energy range 10–100 keV. • Experimental results show better agreement with the model which includes PB in SA up to 30 keV. • At higher photon energy region 30–100 keV the model which describes OB is more accurate. • Experimental results show positive deviations from the entire models at higher energy end spectrum. - Abstract: The total bremsstrahlung spectra in the thick targets of lead acetate trihydrate (Pb(CH{sub 3}COO){sub 2}·3H{sub 2}O), lead nitrate Pb(NO{sub 3}){sub 2} and lead chloride (PbCl{sub 2}) produced by {sup 90}Sr beta particles have been investigated in the photon energy region of 10–100 keV. The experimental bremsstrahlung spectra have been compared with the theoretical models Elwert corrected (non relativistic) Bethe Heitler theory, modified Elwert factor (relativistic) Bethe Heitler theory for ordinary bremsstrahlung and modified Elwert factor (relativistic) Bethe Heitler theory which includes polarization bremsstrahlung in the stripped atom approximation. The experimental results show better agreement with theoretical model that includes polarization bremsstrahlung in stripped approximation in the photon energy region below 30 keV. However, at higher photon energy region 30–100 keV, the theoretical model which describes ordinary bremsstrahlung is more accurate to describe the experimental bremsstrahlung spectra. The experimental results show positive deviations from the entire theoretical models at higher energy end of the spectrum. The results indicate that polarization bremsstrahlung plays important role in the formation of total bremsstrahlung spectra in lead compounds produced by continuous beta particles at low photon energy region of 10–30 keV.

  5. 90Y microsphere therapy: does 90Y PET/CT imaging obviate the need for 90Y Bremsstrahlung SPECT/CT imaging?

    Science.gov (United States)

    Zade, Anand A; Rangarajan, Venkatesh; Purandare, Nilendu C; Shah, Sneha A; Agrawal, Archi R; Kulkarni, Suyash S; Shetty, Nitin

    2013-11-01

    Transarterial radioembolization using Y microspheres is a novel therapeutic option for inoperable hepatic malignancies. As these spheres are radiolucent, real-time assessment of their distribution during the infusion process under fluoroscopic guidance is not possible. Bremsstrahlung radiations arising from 90Y have conventionally been used for imaging its biodistribution. Recent studies have proved that sources of 90Y also emit positrons, which can further be used for PET/computed tomography (CT) imaging. This study aimed to assess the feasibility of 90Y PET/CT imaging in evaluating microsphere distributions and to compare its findings with those of Bremsstrahlung imaging. Thirty-five sessions of 90Y microsphere transarterial radioembolization were performed on 30 patients with hepatic malignancies. 90Y PET/CT imaging was performed within 3 h of therapy. Bremsstrahlung imaging was also performed for each patient. The imaging findings were compared for concordance in the distribution of microspheres. Exact one-to-one correspondence between 90Y PET/CT imaging and 90Y Bremsstrahlung imaging was observed in 97.14% of cases (i.e. in 34/35 cases). Discordance was observed only in one case in which 90Y PET/CT imaging resolved the microsphere uptake in the inferior vena cava tumor thrombus, which was, however, not visualized on Bremsstrahlung imaging. There is good concordance in the imaging findings of 90Y PET/CT and 90Y Bremsstrahlung imaging. 90Y PET/CT imaging scores over the conventionally used Bremsstrahlung imaging in terms of better resolution, ease of technique, and comparable image acquisition time. This makes it a preferred imaging modality for assessment of the distribution of 90Y microspheres.

  6. Continuous spectrum of electromagnetic radiation in the collision of nuclear particles

    International Nuclear Information System (INIS)

    Amusia, M.Y.; Solovyov, A.V.

    1988-01-01

    The bremsstrahlung arising at the scattering of various particles on a nucleus has been considered with the demonstration of an important participation of the nuclear polarization in the collision process

  7. Hard X-ray bremsstrahlung production in solar flares by high-energy proton beams

    Science.gov (United States)

    Emslie, A. G.; Brown, J. C.

    1985-01-01

    The possibility that solar hard X-ray bremsstrahlung is produced by acceleration of stationary electrons by fast-moving protons, rather than vice versa, as commonly assumed, was investigated. It was found that a beam of protons which involves 1836 times fewer particles, each having an energy 1836 times greater than that of the electrons in the equivalent electron beam model, has exactly the same bremsstrahlung yield for a given target, i.e., the mechanism has an energetic efficiency equal to that of conventional bremsstrahlung models. Allowance for the different degrees of target ionization appropriate to the two models (for conventional flare geometries) makes the proton beam model more efficient than the electron beam model, by a factor of order three. The model places less stringent constraints than a conventional electron beam model on the flare energy release mechanism. It is also consistent with observed X-ray burst spectra, intensities, and directivities. The altitude distribution of hard X-rays predicted by the model agrees with observations only if nonvertical injection of the protons is assumed. The model is inconsistent with gamma-ray data in terms of conventional modeling.

  8. Observation of the bremsstrahlung generation in the process of the Rayleigh endash Taylor instability development at gas puff implosion

    International Nuclear Information System (INIS)

    Baksht, R.B.; Fedunin, A.V.; Labetsky, A.Y.; Rousskich, A.G.; Shishlov, A.V.

    1997-01-01

    The electron magnetohydrodynamic model predicts the appearance of anode endash cathode voltage in the process of Rayleigh endash Taylor instability development during gas puff implosions. The appearance of the anode endash cathode voltage should be accompanied by the accelerated electron flow and the generation of the bremsstrahlung radiation. Experiments with neon and krypton gas puffs were performed on the GIT-4 [S. P. Bugaev, et al., Plasma Sci. 18, 115 (1990)] generator (1.6 MA, 120 ns) to observe the bremsstrahlung radiation during the gas puff implosion. Two spikes of the bremsstrahlung radiation were observed in the experiments. The first spike is connected with the gas breakdown; the second one is connected with the final stage of the implosion. The development of the RT instabilities does not initiate the bremsstrahlung radiation, therefore, the absence of anode endash cathode voltage is demonstrated. copyright 1997 American Institute of Physics

  9. Eddy current magnetic bias x-probe qualification and inspection of steam generator Monel 400 tubing in Pickering Nuclear Generating Station

    International Nuclear Information System (INIS)

    Lepine, B.A.; Van Langen, J.; Obrutsky, L.

    2006-01-01

    This paper presents an overview of the x-probe MB 350 eddy current inspection array probe, for detection of open OD axial crack-like flaws in Monel 400 tubes at Pickering Nuclear Generating Station. This report contains a selection of inspection results from the field inspections performed with this probe during the 2003 and 2004 period at Pickering Nuclear Generating Station A and B. During the 2003 in-service eddy current inspection results of Pickering Nuclear Generating Station A (PNGS-A) Unit 2, a 13 mm (0.5 inch) long axial indication was detected by the CTR1 bobbin and CTR2-C4 array probes in Tube R25-C52 of Steam Generator (SG) 11 in the hot leg sludge pile region. An experimental magnetic bias X-probe, specially designed by Zetec for inspection of Monel 400 tubing, was deployed and the indication was characterized as a potential out diameter (OD) axially oriented crack. Post-inspection tube pulling and destructive examination confirmed the presence of an Environmentally Assisted Crack (EAC), approximately 80% deep and 13mm long. Due to the significance of this discovery, Ontario Power Generation (OPG) requested AECL to initiate a program for qualification of the X-probe MB 350 for the detection of OD axial cracks in medium to high magnetic permeability μ r Monel 400 PNGS-A and B steam generator tubing at different locations. The X-probe MB 350 subsequently has been deployed as a primary inspection probe for crack detection for PNGS steam generators. (author)

  10. Electron accelerator-based production of molybdenum-99: Bremsstrahlung and photoneutron generation from molybdenum vs. tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Tsechanski, A. [Ben-Gurion University of the Negev, Department of Nuclear Engineering, P.O. Box 653, Beer-Sheva 84105 (Israel); Bielajew, A.F. [Department of Nuclear Engineering and Radiological Sciences, The University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Archambault, J.P.; Mainegra-Hing, E. [National Research Council of Canada, Ionizing Radiation Standards Laboratory, Ottawa, ON K1A 0R6 (Canada)

    2016-01-01

    A new “one-stage” approach for production of {sup 99}Mo and other radioisotopes by means of an electron linear accelerator is described. It is based on using a molybdenum target both as a bremsstrahlung converter and as a radioisotope producing target for the production of {sup 99}Mo via the photoneutron reaction {sup 100}Mo(γ,n){sup 99}Mo. Bremsstrahlung characteristics, such as bremsstrahlung efficiency, angular distribution, and energy deposition for molybdenum targets were obtained by means of the EGSnrc Monte Carlo simulation code system. As a result of our simulations, it is concluded that a 60 MeV electron beam incident on a thick Mo target will have greater bremsstrahlung efficiency than the same thickness (in units of r{sub 0}) W target, for target thickness z > 1.84r{sub 0}, where r{sub 0} is the electron range. A 50 MeV electron beam incident on a Mo target will result in greater bremsstrahlung efficiency than the same thickness W target (in units of r{sub 0}) for target thickness case: z ⩾ 2.0r{sub 0}. It is shown for the one-stage approach with thicknesses of (1.84–2.0)r{sub 0}, that the {sup 99}Mo-production bremsstrahlung efficiency of a molybdenum target is greater by ∼100% at 30 MeV and by ∼70% at 60 MeV compared to the values for tungsten of the same thickness (in units of the appropriate r{sub 0}) in the traditional two-stage approach (W converter and separate {sup 99}Mo producing target). This advantage of the one-stage approach arises from the fact that the bremsstrahlung produced is attenuated only once from attenuation in the molybdenum converter/target. In the traditional, two-stage approach, the bremsstrahlung generated in the W-converter/target is attenuated both in the converter in the {sup 99}Mo-producing molybdenum target. The photoneutron production yield of molybdenum and tantalum (as a substitute for tungsten) target was calculated by means of the MCNP5 transport code. On the basis of these data, the specific activity

  11. Post-Newtonian gravitational bremsstrahlung

    International Nuclear Information System (INIS)

    Turner, M.; Will, C.M.

    1978-01-01

    We present formulae and numerical results for the gravitational radiation emitted during a low-deflection encounter between two massive bodies (''gravitational bremsstrahlung''). Our results are valid through post-Newtonian order within general relativity. We discuss in detail the gravitational waveform (transverse-traceless part of the metric perturbation tensor), the toal luminosity and total emitted energy, the angular distribution of emitted energy (antenna pattern), and the frequency spectrum. We also present a method of ''boosting'' the accuracy of these quantities to post-3/2-Newtonian order. A numerical comparison of our results with those of Peters and of Kovacs and Thorne shows that the post-Newtonian method is reliable to better than 0.1% at v=0.1c, to a few percent at v=0.35c, and to 10--20% at v=0.5c. We also compare our results with those of Smarr

  12. Nuclear based diagnostics in high-power laser applications

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Marc; Sonnabend, Kerstin; Harres, Knut; Otten, Anke; Roth, Markus [TU Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Vogt, Karsten; Bagnoud, Vincent [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2010-07-01

    High-power lasers allow focused intensities of >10{sup 18} W/cm{sup 2}. During the laser-solid interaction, an intense relativistic electron current is injected from the plasma into the target. One challenge is to characterize the electron dynamic close to the interaction region. Moreover, next generation high-power laser proton acceleration leads to high proton fluxes, which require novel, nuclear diagnostic techniques. We present an activation-based nuclear pyrometry for the investigation of electrons generated in relativistic laser-solid interactions. We use novel activation targets consisting of several isotopes with different photo-neutron disintegration thresholds. The electrons are decelerated inside the target via bremsstrahlung processes. The high-energy bremsstrahlung induces photo-nuclear reactions. In this energy range no disturbing low energy effects are important. Via the pyrometry the Reconstruction of the absolute yield, spectral and spatial distribution of the electrons is possible. For the characterization of proton beams we present a nuclear activation imaging spectroscopy (NAIS). The diagnostic is based on proton-neutron disintegration reactions of copper stacked in consecutive layers. An autoradiography of copper layers leads to spectrally and spatially reconstruction of the beam profile.

  13. Simulation of electron, positron and Bremsstrahlung spectrum generated due to electromagnetic cascade by 2.5 GeV electron hitting lead target using FLUKA code

    International Nuclear Information System (INIS)

    Sahani, P.K.; Dev, Vipin; Haridas, G.; Thakkar, K.K.; Singh, Gurnam; Sarkar, P.K.; Sharma, D.N.

    2009-01-01

    INDUS-2 is a high energy electron accelerator facility where electrons are accelerated in circular ring up to maximum energy 2.5 GeV, to generate synchrotron radiation. During normal operation of the machine a fraction of these electrons is lost, which interact with the accelerator structures and components like vacuum chamber and residual gases in the cavity and hence generates significant amount of Bremsstrahlung radiation. The Bremsstrahlung radiation is highly dependent on the incident electron energy, target material and its thickness. The Bremsstrahlung radiation dominates the radiation environment in such electron storage rings. Because of its broad spectrum extending up to incident electron energy and pulsed nature, it is very difficult to segregate the Bremsstrahlung component from the mixed field environment in accelerators. With the help of FLUKA Monte Carlo code, Bremsstrahlung spectrum generated from 2.5 GeV electron on bombardment of high Z lead target is simulated. To study the variation in Bremsstrahlung spectrum on target thickness, lead targets of 3, 6, 9, 12, 15, 18 mm thickness was used. The energy spectrum of emerging electron and positron is also simulated. The study suggests that as the target thickness increases, the emergent Bremsstrahlung photon fluence increases. With increase in the target thickness Bremsstrahlung photons in the spectrum dominate the low energy part and degrade in high energy part. The electron and positron spectra also extend up to incident electron energy. (author)

  14. Nuclear borehole probes - theory and experiments

    International Nuclear Information System (INIS)

    Joergensen, J.L.; Korsbech, U.; Gynther Nielsen, K.; Oelgaard, P.L.

    1985-06-01

    The report gives a summary of the theoretical and expeimental work on borehole probes that has been performed since 1971 at The Department of Electrophysics, The Technical University of Denmark. The first part of the report concerns the use of a spectral natural gamma-ray probe (SNG-probe), which is used for measurements of the spectral distribution of the gamma-rays of the geological strata around a borehole. In general the spectrum is divided into three parts - the gamma-rays from potassium-40, from thorium-232 and daughters, and from uranium-238 and daughters. A set of curves showing the intensities of the gamm-radiation from K, Th, and U versus depth is called a SNG-log. If proper calibrated, the SNG-log gives the concentration of Th, U, and K in the formation surrounding the borehole. Initially the basis for an interpretation of SNG-logs is discussed. Then follows a description og some SNG-problems designed and built by The Department of Electrophysics, and a discussion of the calibration of SNG-probes. Some examples of SNG-logs are presented, and some general comments on the use of SNG-logs are given. The second part of the report concerns mainly the development of theoretical models for neutron-neutron probes, gamma-gamma probes, and pulsed-neutron probes. The purpose of this work has been to examine how well the models correlate with measured results and - where reasonable agreement is found - to use the models in studies of the factors that affect the probe responses in interpretation of experimental results and in probe design. (author)

  15. Bremsstrahlung converter debris shields: test and analysis

    International Nuclear Information System (INIS)

    Reedy, E.D. Jr.; Perry, F.C.

    1983-10-01

    Electron beam accelerators are commonly used to create bremsstrahlung x-rays for effects testing. Typically, the incident electron beam strikes a sandwich of three materials: (1) a conversion foil, (2) an electron scavenger, and (3) a debris shield. Several laboratories, including Sandia National Laboratories, are developing bremsstrahlung x-ray sources with much larger test areas (approx. 200 to 500 cm 2 ) than ever used before. Accordingly, the debris shield will be much larger than before and subject to loads which could cause shield failure. To prepare for this eventuality, a series of tests were run on the Naval Surface Weapons Center's Casino electron beam accelerator (approx. 1 MeV electrons, 100 ns FWHM pulse, 45 kJ beam energy). The primary goal of these tests was to measure the stress pulse which loads a debris shield. These measurements were made with carbon gages mounted on the back of the converter sandwich. At an electron beam fluence of about 1 kJ/cm 2 , the measured peak compressive stress was typically in the 1 to 2 kbar range. Measured peak compressive stress scaled in a roughly linear manner with fluence level as the fluence level was increased to 10 kJ/cm 2 . The duration of the compressive pulse was on the order of microseconds. In addition to the stress wave measurements, a limited number of tests were made to investigate the type of damage generated in several potential shield materials

  16. Nuclear resonance scattering of synchrotron radiation as a unique electronic, structural and thermodynamic probe

    International Nuclear Information System (INIS)

    Alp, E. Ercan; Sturhahn, Wolfgang; Toellner, Thomas S.; Zhao, Jiyong; Leu, Bogdan M.

    2012-01-01

    Discovery of Moessbauer effect in a nuclear transition was a remarkable development. It revealed how long-lived nuclear states with relatively low energies in the kiloelectron volt (keV) region can be excited without recoil. This new effect had a unique feature involving a coupling between nuclear physics and solid-state physics, both in terms of physics and sociology. Physics coupling originates from the fact that recoilless emission and absorption or resonance is only possible if the requirement that nuclei have to be bound in a lattice with quantized vibrational states is fulfilled, and that the finite electron density on the nucleus couples to nuclear degrees of freedom leading to hyperfine interactions. thus, Moessbauer spectroscopy allows peering into solid-state effects using unique nuclear transitions. Sociological aspects of this coupling had been equally startling and fruitful. The interaction between diverse scientific communities, who learned to use Moessbauer spectroscopy proved to be very valuable. For example, biologists, geologists, chemists, physics, materials scientists, and archeologists, all sharing a common spectroscopic technique, also learned to appreciate the beauty and intricacies of each other's fields. As a laboratory-based technique, Moessbauer spectroscopy matured by the end of the 1970s. Further exciting developments took place when accelerator-based techniques were employed, like synchrotron radiation or 'in-beam'Moessbauer experiments with implanted radioactive ions. More recently, two Moessbauer spectrometers on the surface of the Mars kept the technique vibrant and viable up until present time. In this chapter, the authors look into some of the unique aspects of nuclear resonance excited with synchrotron radiation as a probe of condensed matter, including magnetism, valence, vibrations, and lattice dynamics, and review the development of nuclear resonance inelastic x-ray scattering (NRIXS) and synchrotron Moessbauer spectroscopy

  17. Electron-electron Bremsstrahlung for bound target electrons

    International Nuclear Information System (INIS)

    Haug, E.

    2008-01-01

    For the process of electron-electron (e-e) Bremsstrahlung the momentum and energy distributions of the recoiling electrons are calculated in the laboratory frame. In order to get the differential cross section and the photon spectrum for target electrons which are bound to an atom, these formulae are multiplied by the incoherent scattering function and numerically integrated over the recoil energy. The effect of atomic binding is most pronounced at low energies of the incident electrons and for target atoms of high atomic numbers. The results are compared to those of previous calculations. (authors)

  18. Secondary-electron-bremsstrahlung imaging for proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Mitsutaka; Nagao, Yuto [Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-Machi, Takasaki, Gunma (Japan); Ando, Koki; Yamamoto, Seiichi [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-Ku, Nagoya, Aichi (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, 1-1-1 Hirate-cho, Kita-Ku, Nagoya, Aichi (Japan); Kataoka, Jun [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo (Japan); Kawachi, Naoki [Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-Machi, Takasaki, Gunma (Japan)

    2016-10-11

    A feasibility study on an imaging technique of a therapeutic proton-beam trajectory using a gamma camera by measuring secondary electron bremsstrahlung (SEB) was performed by means of Monte Carlo simulations and a beam-irradiation experiment. From the simulation and experimental results, it was found that a significant amount of SEB yield exists between the beam-injection surface and the range position along the beam axis and the beam trajectory is clearly imaged by the SEB yield. It is concluded that the SEB imaging is a promising technique for monitoring of therapeutic proton-beam trajectories.

  19. Multi-Regge amplitudes for bremsstrahlung in e+e- backward scattering

    International Nuclear Information System (INIS)

    Ermolaev, B.I.; Lipatov, L.N.

    1988-01-01

    Using the method of factorization, equations are obtained for the inelastic on-shell amplitudes describing the asymptotic behavior of e + e - backward scattering with emission of bremsstrahlung photons in the doubly logarithmic approximation. Explicit expressions are found for these amplitudes in the case in which the photons are emitted with multi-Regge kinematics

  20. A Comparison of Laser-induced Bremsstrahlung and Laser Compton Scattering for (γ, n) Photo-transmutation of Hazardous Nuclear Waste

    International Nuclear Information System (INIS)

    Rehman, Haseeb ur; Lee, Jiyoung; Kim, Yonghee

    2015-01-01

    This paper also presents sensitivity analysis to yield the maximum possible photo-transmutation rates. In general the possibility of radionuclide transmutation using photo-neutron reaction is evaluated in this work. In this paper a detailed methodology to calculate transmutation reaction rates using Laser Induced Bremsstrahlung (LIB) and Laser Compton Scattering (LCS) has been discussed. The methodology was validated by comparing the calculated reaction rates against published data in publically accessed literatures. In the second half of the paper, the authors present a novel concept to narrow down the LCS photon spectrum to an energy range that matches with the resonance region of a particular radionuclide. This is particularly useful considering hazardous waste is usually a mix of different isotopes. As such, being able to tune the LCS photon into any narrow energy range so as to selectively transmute any particular isotope of interest in the hazardous waste mixture would be very desirable. LCS spectrum is highly sensitive to the electron beam energy, laser power, laser luminosity and Compton backscattering angle. From the results it is quite evident that LCS is much better option for the radionuclide transmutation as reaction rates for the LCS is much higher than LIB method even for very small laser power. It can be seen even for the optimistic reaction rate calculations with Bremsstrahlung method reaction rate is much lower than LCS case for 10 Hz repetition rate. If repetition rate of laser 100 Hz then LIB reaction rate has the same order of the magnitude as the reaction rate via LCS. Higher Laser Powers can yield very high transmutation rates

  1. Investigation of relativistic laser-plasmas using nuclear diagnostics; Untersuchung relativistischer Laserplasmen mittels nukleardiagnostischer Verfahren

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Marc M.

    2011-01-19

    The present work explores with the development of a novel nuclear diagnostic method for the investigation of the electron dynamics in relativistic laser-plasma interactions. An additional aim of this work was the determination of the real laser peak intensity via the interaction of an intense laser short-pulse with a solid target. The nuclear diagnostics is based on a photo-neutron disintegration nuclear activation method. The main constituent of the nuclear diagnostic are novel pseudoalloic activation targets as a kind of calorimeter to measure the high-energy bremsstrahlung produced by relativistic electrons. The targets are composed of several stable isotopes with different ({gamma},xn)-reaction thresholds. The activated nuclides were identified via the characteristic gamma-ray decay spectrum by using high-resolution gamma spectroscopy after the laser irradiation. Via the gamma spectroscopy the ({gamma},xn)-reaction yields were determined. The high-energy bremsstrahlung spectrum has been deconvolved using a novel analysis method based on a modified Penfold-Leiss method. This facilitates the reconstruction of the spectrum of bremsstrahlung photons without any anticipated fit procedures. Furthermore, the characterization of the corresponding bremsstrahlung electrons in the interaction zone is accessible immediately. The consolidated findings about the properties of the relativistic electrons were used to determine the real peak intensity at the laser-plasma interaction zone. In the context of this work, experiments were performed at three different laser facilities. First Experiments were carried out at the 100 TW laser facility at Laboratoire pour l'Utilisation des Lasers Intense (LULI) in France and supplementary at the Vulcan laser facility at Rutherford Appleton Laboratory (RAL) in United Kingdom. The main part of the activation experiments were performed at the PHELIX laser facility (Petawatt High Energy Laser for heavy Ion EXperiments) at GSI

  2. Dose estimative in operators during petroleum wells logging with nuclear wireless probes through computer modelling

    International Nuclear Information System (INIS)

    Souza, Edmilson Monteiro de; Silva, Ademir Xavier da; Lopes, Ricardo T.; Correa, Samanda Cristine Arruda; Rocha, Paula L.F.

    2011-01-01

    This paper evaluates the absorbed dose and the effective dose on operators during the petroleum well logging with nuclear wireless that uses gamma radiation sources. To obtain the data, a typical scenery of a logging procedure will be simulated with MCNPX Monte Carlo code. The simulated logging probe was the Density Gamma Probe - TRISOND produced by Robertson Geolloging. The absorbed dose values were estimated through the anthropomorphic simulator in male voxel MAX. The effective dose values were obtained using the ICRP 103

  3. Lepton-pair production by bremsstrahlung in central relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Lippert, T.; Becker, U.; Gruen, N.; Scheid, W.; Soff, G.

    1988-03-01

    We study the production of lepton-pairs by classical bremsstrahlung in central relativistic heavy-ion collisions. For the stopping of the nuclei we assume a simple model of point charges and a deceleration time. Pair creation probabilities are calculated in first order perturbation theory. (orig.)

  4. Estimation of Electron Dose Delivered by a 0.4 MeV Accelerator from Bremsstrahlung Dose Measurements

    DEFF Research Database (Denmark)

    Karadjov, A. G.; Hansen, Jørgen-Walther

    1980-01-01

    Determination of a 0.4 MeV electron dose from a bremsstrahlung dose measurement using a converter-detector system is considered. The detector used is a Frickle dosimeter, and the converters are aluminum, copper and lead foils. Optimal converter thickness is ascertained experimentally for each mat...... materials within a Z-range of 13–82. A linear relation is found between bremsstrahlung dose and electron dose ranging from 2 to 20 Mrad. Finally the effect of converter area on detector response is studied....

  5. Planar gamma camera imaging and quantitation of Yttrium-90 bremsstrahlung

    International Nuclear Information System (INIS)

    Shen, S.; DeNardo, G.L.; Yuan, A.

    1994-01-01

    Yttrium-90 is a promising radionuclide for radioimmunotherapy of cancer because of its energetic beta emissions. Therapeutic management requires quantitative imaging to assess the pharmacokinetics and radiation dosimetry of the 90 Y-labeled antibody. Conventional gamma photon imaging methods cannot be easily applied to imaging of 90 Y-bremsstrahlung because of its continuous energy spectrum. The sensitivity, resolution and source-to-background signal ratio (S/B) of the detector system for 90 Y-bremsstrahlung were investigated for various collimators and energy windows in order to determine optimum conditions for quantitative imaging. After these conditions were determined, the accuracy of quantitation of 90 Y activity in an Alderson abdominal phantom was examined. When the energy-window width was increased, the benefit of increased sensitivity outweighed degradation in resolution and S/B ratio until the manufacturer's energy specifications for the collimator were exceeded. Using the same energy window, the authors improved resolution and S/B for the medium-energy (ME) collimator when compared to the low-energy, all-purpose (LEAP) collimator, and there was little additional improvement using the high-energy (HE) collimator. Camera sensitivity under tissue equivalent conditions was 4.2 times greater for the LEAP and 1.7 times greater for the ME collimators when compared to the HE collimator. Thus, the best, most practical selections were found to be the ME collimator and an energy window of 55-285 keV. When they used these optimal conditions for image acquisition, the estimation of 90 Y activity in organs and tumors was within 15% of the true activities. The results for this study suggest that reasonable accuracy can be achieved in clinical radioimmunotherapy using 90 Y-bremsstrahlung quantitation. 28 refs., 5 figs., 7 tabs

  6. Elemental characterization of individual glia and glioma cells in the nuclear microprobe

    International Nuclear Information System (INIS)

    Lindh, U.

    1982-01-01

    To investigate whether variations in levels of microelements are reflected at the cellular level, a study of cultured cells was undertaken. For elemental characterization were chosen human glia and glioma cell lines. The cells were freeze-dried and about 1000 cells of each line were analyzed in the nuclear microprobe with a probe diameter of 10 μm. Scanning of the specimens under the beam made possible heat reduction and the X-ray spectrum induced was continuously recorded and subsequently processed in the computer. Elemental maps of the cells were then generated and the information from each member of the cell populations could be considered as well as the population statistics. Mass determination was accomplished by means of the bremsstrahlung continuum intensity. The main feature resulting from the characterization was that the glioma cells in average held appreciably higher contents of copper and zinc than did the glia cells. (orig.)

  7. Routine average effective charge calculation using visible Bremsstrahlung emission and comparison with the impurity transport code of Tore Supra

    International Nuclear Information System (INIS)

    Guirlet, R.; Mattioli, M.; DeMichelis, C.; Hess, W.; Pecquet, A.L.

    1995-01-01

    Effective charge measurements and calculations are presented for the Tore Supra, using visible Bremsstrahlung diagnostics. The measurements, are presented together with a reliability test of the results are discussed, by means of an impurity transport code simulating all available experimental data (XUV line spectroscopy, soft X-ray emission and Bremsstrahlung). (author) 5 refs.; 10 figs

  8. The Schiff angular bremsstrahlung distribution from composite media

    International Nuclear Information System (INIS)

    Taylor, M.L.; Dalton, B.; Franich, R.D.

    2012-01-01

    The Schiff differential for the angular distribution of bremsstrahlung is widely employed, but calculations involving composite materials (i.e. compounds and mixtures) are often undertaken in a somewhat ad hoc fashion. In this work, we suggest an alternative approach to power-law estimates of the effective atomic number utilising Seltzer and Berger’s combined approach in order to generate single-valued effective atomic numbers applicable over a large energy range (in the worst case deviation from constancy of about 2% between 10 keV and 1 GeV). Differences with power-law estimates of Z for composites are potentially significant, particularly for low-Z media such as biological or surrogate materials as relevant within the context of medical physics. As an example, soft tissue differs by >70% and cortical bone differs by >85%, while for high-Z composites such as a tungsten–rhenium alloy the difference is of the order of 1%. Use of the normalised Schiff formula for shape only does not exhibit strong Z dependence. Consequently, in such contexts the differences are negligible – the power-law approach overestimates the magnitude by 1.05% in the case of water and underestimates it by <0.1% for the high-Z alloys. The differences in the distribution are most pronounced for small angles and where the bremsstrahlung quanta are low energy.

  9. An algorithm to include the bremsstrahlung component in the determination of the absorbed dose in electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Klevenhagen, S C [The Royal London Hospital, London (United Kingdom). Medical Physics Dept.

    1996-08-01

    Currently used dosimetry protocols for absolute dose determination of electron beams from accelerators in radiation therapy do not account for the effect of the bremsstrahlung contamination of the beam. This results in slightly erroneous doses calculated from ionization chamber measurements. In this report the deviation is calculated and an improved algorithm, which accounts for the effect of the bremsstrahlung component of the beam, is suggested. (author). 14 refs, 2 figs, 1 tab.

  10. Pauli principle in the soft-photon approach to proton-proton bremsstrahlung

    NARCIS (Netherlands)

    Liou, MK; Timmermans, R; Gibson, BF

    1996-01-01

    A relativistic and manifestly gauge-invariant soft-photon amplitude, which is consistent with the soft-photon theorem and satisfies the Pauli principle, is derived for the proton-proton bremsstrahlung process. This soft-photon amplitude is the first two-u-two-t special amplitude to satisfy all

  11. A study of LPM suppression of bremsstrahlung at 25 GeV

    International Nuclear Information System (INIS)

    Anthony, P.; Becker-Szendy, R.; Bosted, P.

    1993-03-01

    We are making an accurate measurement of the LPM suppression of bremsstrahlung with 25 GeV electrons. By using a 120 pulses per second beam, a precise BGO calorimeter, and spectrometer to tag the outgoing electrons, we are able to make an accurate measurement of the bremsstrahlung photons in the 0-400 MeV region, where the Bethe Heitler and LPM predictions differ. We are taking data with targets made of carbon, uranium, tungsten and iron, with thicknesses in the 2% to 6% X 0 range. In addition, we are taking data with two very thin gold targets. The latter have thicknesses that are comparable to or less than the LPM formation zone length, and so should not exhibit LPM suppression. We are also studying photons of a few MeV in energy, to test the closely related longitudinal density effect predicted by Ter-Mikaelian in which very low energy photon emission is suppressed due to dielectric effects of the medium

  12. Neutrino-antineutrino pair production by hadronic bremsstrahlung

    Science.gov (United States)

    Bacca, Sonia

    2016-09-01

    I will report on recent calculations of neutrino-antineutrino pair production from bremsstrahlung processes in hadronic collisions and consider temperature conditions relevant for core collapse supernovae. Earlier studies on bremsstrahlung from neutron-neutron collisions showed that the approximation used in typical supernova simulation to model this process differs by about a factor of 2 from predictions based on chiral effective field theory, where the chiral expansion of two-body forces is considered up to the next-to-next-to-next-to-leading order. When the density of neutrons is large enough this process may compete with other non-hadronic reactions in the production of neutrinos, in particular in the case of μ and τ neutrinos, which are not generated by charged-current reactions. A natural question to ask is then: what is the effect of neutrino pair production from collisions of neutrons with finite nuclei? To tackle this question, we recently have addressed the case of neutron- α collisions, given that in the P-wave channels the neutron- α scattering features a resonance near 1 MeV. We find that the resonance leads to an enhanced contribution in the neutron spin structure function at temperatures in the range of 0 . 1 - 4 MeV. For significant density fractions of α in this temperature range, this process is competitive with contributions from neutron-neutron scattering. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada. This work was supported in parts by the Natural Sciences and Engineering Research Council (Grant Number SAPIN-2015-0003).

  13. Diffractive production off nuclei-shadow of hadronic bremsstrahlung

    International Nuclear Information System (INIS)

    Bialas, A.; Czyz, W.

    1974-01-01

    Diffractive production on nuclei is calculated using as an input a specific model for diffractive production on nucleons. In this model diffractive production is described as a shadow of non-diffractive multiple production of particles. The mechanism for non-diffractive production is taken to be hadronic bremsstrahlung of independently produced clusters. It is shown that such a model naturally explains the strikingly simple pattern of absorption observed in coherent production on nuclei. Possible generalizations of these results are indicated. (author)

  14. The isomeric ratios in photonuclear reactions of natural barium induced by bremsstrahlungs with endpoint energies in the giant dipole resonance region

    International Nuclear Information System (INIS)

    Tran Duc Thiep; Truong Thi An; Phan Viet Cuong; Nguyen The Vinh

    2012-01-01

    We have determined the isomeric ratios in 130 Ba(γ, n) 129m,g Ba, 132 Ba(γ, n) 131m,g Ba and 134 Ba(γ, n) 133m,g Ba photonuclear reactions of natural barium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of 60 Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors. (author)

  15. Coulomb correction calculations of pp Bremsstrahlung

    International Nuclear Information System (INIS)

    Katsogiannis, A.; Amos, K.; Jetter, M.; von Geramb, H.V.

    1994-01-01

    The effects of the Coulomb interaction upon the photon cross section and analyzing power from pp Bremsstrahlung have been studied in detail. Off-shell properties of the Coulomb T matrices have been considered but the associated, Coulomb modified, hadronic T matrices are important elements in any analyses of low energy, forward proton scattering data. At the lowest energy considered (5 MeV), the full calculations gave cross sections that were half the size of those found without Coulomb effects or with a simple model approximation to them. With increasing energy, the cross sections varied to those characteristic of magnetic interaction dominance and the specific differences due to Coulomb effects diminished. 47 refs., 7 figs

  16. Electroweak one-loop corrections for e+e- annihilation into t anti t including hard bremsstrahlung

    International Nuclear Information System (INIS)

    Fleischer, J.; Leike, A.; Riemann, T.; Werthenbach, A.

    2003-01-01

    We present the complete electroweak one-loop corrections to top-pair production at a linear e + e - collider in the continuum region. Besides weak and photonic virtual corrections, real hard bremsstrahlung with simple realistic kinematical cuts is included. For the bremsstrahlung we advocate a semi-analytical approach with a high numerical accuracy. The virtual corrections are parameterized through six independent form factors, suitable for Monte Carlo implementation. Alternatively, our numerical package Topfit, a stand-alone code, can be utilized for the calculation of both differential and integrated cross sections as well as forward-backward asymmetries. (orig.)

  17. Normal or abnormal isospin-fractionation as a qualitative probe of nuclear symmetry energy at supradensities

    International Nuclear Information System (INIS)

    Guo, Wenmei; Yong, Gaochan; Wang, Yongjia; Li, Qingfeng; Zhang, Hongfei; Zuo, Wei

    2014-01-01

    Within two different frameworks of isospin-dependent transport model, effect of nuclear symmetry energy at supradensities on the isospin-fractionation (IsoF) was investigated. With positive/negative symmetry potential at supradensities (i.e., values of symmetry energy increase/decrease with density above saturation density), for energetic nucleons, the value of neutron to proton ratio of free nucleons is larger/smaller than that of bound nucleon fragments. Compared with extensively studied quantitative observables of nuclear symmetry energy, the normal or abnormal isospin-fractionation of energetic nucleons can be a qualitative probe of nuclear symmetry energy at supradensities

  18. Novel probe for determining the size and position of a relativistic electron beam

    International Nuclear Information System (INIS)

    Orzechowski, T.J.; Koehler, H.; Edwards, W.; Nelson, M.; Marshall, B.

    1984-01-01

    In order to determine the size and position of a relativistic electron beam inside the wiggler magnetic field of a Free Electron Laser (FEL), we have developed a new probe which intercepts the electron beam on a high Z target and monitors the resulting bremsstrahlung radiation. The probe is designed to move along the entire three meters of the wiggler. This FEL is designed to operate in the microwave region (2 to 8 mm) and the interaction region is an oversized waveguide with a cross section 3 cm x 9.8 cm. The axial probe moves inside this waveguide. The probe stops the electron beam on a Tantalum target and the resulting x-rays are scattered in the forward direction. A scintillator behind the beam stop reacts to the x-rays and emits visible light in the region where the x-rays strike. An array of fiber optics behind the scintillator transmits the visible light to a Reticon camera system which images the visible pattern from the scintillator. Processing the optical image is done by digitizing and storing the image and/or recording the image on video tape. Resolution and performance of this probe will be discussed

  19. Electron bremsstrahlung in collisions of 223 MeV/u He-like uranium ions with gaseous targets

    Energy Technology Data Exchange (ETDEWEB)

    Ludziejewski, T.; Beyer, H.; Bosch, F.; Brinzanescu, O.; Franzke, B.; Kozhuharov, C.; Liesen, D.; Menzel, G.; Meier, J.; Mokler, P.H.; Reich, H.; Steck, M.; Stenner, L. [Gesellschaft fuer Schwerionenforschung, D-64220 Darmstadt (Germany); Stoehlker, Th. [University of Frankfurt, D-60486 Frankfurt (Germany); Gesellschaft fuer Schwerionenforschung, D-64220 Darmstadt (Germany); Keller, S. [University of Frankfurt, D-60054 Frankfurt (Germany); Dunford, R.W. [Argonne National Laboratory, Argonne, IL 60439 (United States); Livingston, A.E. [University of Notre Dame, Indiana 4556 (United States); Rymuza, P. [Institute for Nuclear Studies, 05-400 Swierk (Poland); Stachura, Z. [Institute of Nuclear Physics, 31-342 Cracow (Poland); Swiat, P.; Warczak, A. [Jagiellonian University, 30-059 Cracow (Poland)

    1998-06-14

    The bremsstrahlung process in the domain of strong Coulomb fields has been investigated for N{sub 2} and Ar target electrons colliding with He-like uranium ions at 223 MeV/u. The differential cross sections for bremsstrahlung were measured at laboratory observation angles of 48 deg., 90 deg., and 132 deg. Substantial discrepancies were found between the experimental cross sections and the first-order Born approximation calculations. The reported data provide a new testing ground for non-perturbative treatment of the coupling between radiation and matter in the presence of strong fields. (author)

  20. Electron bremsstrahlung in collisions of 223 MeV/u He-like uranium ions with gaseous targets

    International Nuclear Information System (INIS)

    Ludziejewski, T.; Beyer, H.; Bosch, F.; Brinzanescu, O.; Franzke, B.; Kozhuharov, C.; Liesen, D.; Menzel, G.; Meier, J.; Mokler, P.H.; Reich, H.; Steck, M.; Stenner, L.; Stoehlker, T.; Keller, S.; Dunford, R.W.; Livingston, A.E.; Rymuza, P.; Stachura, Z.; Swiat, P.; Warczak, A.

    1997-09-01

    The bremsstrahlung process in the domain of strong Coulomb fields has been investigated for N 2 and Ar target electrons colliding with He-like uranium ions at 223 MeV/u. The doubly differential cross sections for bremsstrahlung were measured at the laboratory observation angles of 48 , 90 , and 132 . Substantial discrepancies were found between the experimental cross secions and the first order Born approximation calculations. The reported data provide a new testing ground for non-perturbative treatment of the coupling between radiation and matter in the presence of strong fields. (orig.)

  1. Electron bremsstrahlung in collisions of 223 MeV/u He-like uranium ions with gaseous targets

    Energy Technology Data Exchange (ETDEWEB)

    Ludziejewski, T.; Beyer, H.; Bosch, F.; Brinzanescu, O.; Franzke, B.; Kozhuharov, C.; Liesen, D.; Menzel, G.; Meier, J.; Mokler, P.H.; Reich, H.; Steck, M.; Stenner, L. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Stoehlker, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Frankfurt Univ. (Germany); Keller, S. [Frankfurt Univ. (Germany); Dunford, R.W. [Argonne National Lab., IL (United States); Livingston, A.E. [Notre Dame Univ., IN (United States); Rymuza, P. [Institute for Nuclear Studies, Swierk (Poland); Stachura, Z. [Henryk Niewodniczanski Inst. of Nuclear Physics, Cracow (Poland); Swiat, P.; Warczak, A. [Jagiellonian Univ., Krakow (Poland)

    1997-09-01

    The bremsstrahlung process in the domain of strong Coulomb fields has been investigated for N{sub 2} and Ar target electrons colliding with He-like uranium ions at 223 MeV/u. The doubly differential cross sections for bremsstrahlung were measured at the laboratory observation angles of 48 , 90 , and 132 . Substantial discrepancies were found between the experimental cross secions and the first order Born approximation calculations. The reported data provide a new testing ground for non-perturbative treatment of the coupling between radiation and matter in the presence of strong fields. (orig.) 35 refs.

  2. Internal bremsstrahlung spectra from 185W and 32P

    International Nuclear Information System (INIS)

    Babu, R.P.; Murty, K.N.; Murty, V.A.N.

    1976-01-01

    The internal bremsstrahlung spectra from the β decay of 185 W and 32 P were measured using a NaI(Tl) scintillation spectrometer with a standard geometrical arrangement. After making all the necessary corrections the experimental results are compared with the allowed theory of the Knipp, Uhlenbeck, and Bloch (KUB theory) and also with the Coulomb corrected theories of Lewis, Ford, and Nilsson. In the case of 185 W it is found that from 78 to 200 keV the experimental distribution is in good agreement with the KUB theory whereas beyond 200 keV and below 78 keV the experimental points are far above even the highest Coulomb corrected theoretical distribution of Nilsson. The internal bremsstrahlung from this isotope has not been previously investigated. In the case of 32 P the experimental relative intensity spectrum is compared with the KUB theory and also with the Coulomb corrected theory of Lewis and Ford. Fairly good agreement is obtained from 30 to 200 keV with the KUB theory but in the energy region from 200 to 900 keV, the experimental results deviate positively from both the KUB and Lewis and Ford theories. The experimental excess over the Lewis and Ford theory is 15% on the average

  3. A detector for use in high energy bremsstrahlung shielding studies

    International Nuclear Information System (INIS)

    Wilson, O.J.; Thomson, J.E.M.

    1983-01-01

    The design, development and calibration of a detector based on the principle of the Moxon-Rae detector is discussed. It is ideally suited to the measurement of the energy fluence of photons transmitted through a thick shield which has been irradiated with high energy bremsstrahlung. The detection sensitivity is 10 4 to 10 5 times that of the P2 ion chamber

  4. A no-tune no-match wideband probe for nuclear quadrupole resonance spectroscopy in the VHF range

    Science.gov (United States)

    Scharfetter, Hermann; Petrovic, Andreas; Eggenhofer, Heidi; Stollberger, Rudolf

    2014-12-01

    Nuclear quadrupole resonance (NQR) spectroscopy is a method for the characterization of chemical compounds containing so-called quadrupolar nuclei. Similar to nuclear magnetic resonance (NMR), the sample under investigation is irradiated with strong radiofrequency (RF) pulses, which stimulate the emission of weak RF signals from the quadrupolar nuclei. The signals are then amplified and Fourier transformed so as to obtain a spectrum. In principle, narrowband NQR spectra can be measured with NMR spectrometers. However, pure NQR signals require the absence of a static magnetic field and several special applications require the characterization of a substance over a large bandwidth, e.g. 50-100% of the central frequency, which is hardly possible with standard NMR equipment. Dedicated zero-field NQR equipment is not widespread and current concepts employ resonating probes which are tuned and matched over a wide range by using mechanical capacitors driven by stepper motors. While providing the highest signal to noise ratio (SNR) such probes are slow in operation and can only be operated from dedicated NMR consoles. We developed a low-cost NQR wideband probe without tuning and matching for applications in the very high frequency (VHF) range below 300 MHz. The probe coil was realized as part of a reactive network which approximates an exponential transmission line. The input reflection coefficient of the two developed prototype probe coils is ≤ 20 dB between 90-145 MHz and 74.5-99.5 MHz, respectively. Two wideband NQR spectra of published test substances were acquired with an SNR of better than 20 dB after sufficient averaging. The measured signals and the SNR correspond very well to the theoretically expected values and demonstrate the feasibility of the method. Because there is no need for tuning and matching, our probes can be operated easily from any available NMR console.

  5. Monitoring system of energy characteristics of electron beam during shaping process of power bremsstrahlung pulses

    International Nuclear Information System (INIS)

    Mordasov, N.G.; Ulimov, V.N.; Bryksin, V.A.; Shiyan, V.D.

    2005-01-01

    One proposes a procedure and a device to monitor dynamic and integral characteristics of electron power beams of high-current pulsed accelerators (HCPA) operating under Bremsstrahlung radiation mode. One obtained static and dynamic transfer characteristics for various types of heterogenous targets-converters under operation of UIN-10 HCPA with up to 4 MeV energy electrons, up to 60 kA current and 6 x 10 -8 -2 x 10 -6 s pulse efficient duration. One demonstrated the capabilities of the complex diagnostics of acceleration of electron beams by HCPA with simultaneous determination of parameters of the Bremsstrahlung radiation at the local point of the field behind the target-converter [ru

  6. Possibilities for a neutron-proton bremsstrahlung experiment at WNR/LAMPF

    International Nuclear Information System (INIS)

    Wender, S.A.; Nelson, R.O.; Laymon, C.M.; Schillaci, M.; Gibson, B.F.

    1990-01-01

    The high energy and high intensity of the continuous energy (white) neutron source at the WNR target area of the Los Alamos Meson Physics Facility (LAMPF) may make possible a direct measurement of the neutron-proton bremsstrahlung (NPB) cross section. Several recent papers have discussed the operation of the WNR white neutron source in detail so we will just include a short description of the relevant properties of the source in this article. Next the authors will describe one possible method of measuring the NPB cross section which is based on two calorimetric detectors that measure the energies of the scattered neutrons and the recoil protons. Although there are many other possible experimental approaches and geometries, such as measuring the bremsstrahlung gamma ray directly with a multi-element possibilities in this paper. There are several advantages in using a white neutron source for this type of measurement. First, a wide range of incident neutron energies may be covered. In the case of the WNR, the energy range is from below 50 MeV to over 400 MeV which is above the pion production threshold. Second, all incident neutron energies are measure simultaneously. 6 refs., 5 figs

  7. Radiation and nuclear technologies in the Institute for Nuclear Research NAS of Ukraine

    International Nuclear Information System (INIS)

    Vishnevs'kij, Yi.M.; Gajdar, G.P.; Kovalenko, O.V.; Kovalyins'ka, T.V.; Kolomyijets', M.F.; Lips'ka, A.Yi.; Litovchenko, P.G.; Sakhno, V.Yi.; Shevel', V.M.

    2014-01-01

    The monograph describes some of the important developments of radiation and nuclear technology, made in INR NAS Ukraine. The first section describes radiation producing new materials and services using electrons with energies up to 5 MeV and Bremsstrahlung X-rays. We describe the original technology using ion emissions of the low and very low energies. In the second section the nuclear technologies, where ions, neutrons and other high-energy particles with energies are used, provide modification of the structure of matter nuclei in particular - radioactive isotopes for industrial and medical supplies and devices based on them.

  8. Inner bremsstrahlung accompanying β-decay of 170Tm

    International Nuclear Information System (INIS)

    Gundu Rao, K.S.; Venkataramaiah, P.; Gopala, K.; Sanjeeviah, H.

    1981-01-01

    Inner bremsstrahlung accompanying non-unique first-forbidden β-decay of 170 Tm has been measured employing a magnetic deflection technique with a (4.5 x 5.1 cm) NaI(Tl) scintillation spectrometer in the energy region 200 keV to 900 keV. The raw spectrum is unfolded using the Liden and Starfelt procedure, and compared with the theories of KUB, Lewis and Ford, and Ford and Martin. The results are close to the Lewis and Ford theory over the major portion of the measured spectrum. (orig.)

  9. Weibel instability due to inverse bremsstrahlung absorption

    International Nuclear Information System (INIS)

    Bendib, A.; Bendib, K.; Bendib, A.; Bendib, K.; Sid, A.; Bendib, K.

    1997-01-01

    A new Weibel source due to the inverse bremsstrahlung absorption is presented. It has been shown that in homogeneous plasmas, this mechanism may drive strong collisionless Weibel modes with growth rates of order of γ∼10 11 s -1 and negligible group velocities. In the laser-produced plasmas, for short laser wavelengths (λ L 10 14 W/cm 2 ), this Weibel source is most efficient as the ones due to the heat flux and the plasma expansion. The useful scaling law of the convective e-foldings, with respect to the laser and the plasma parameters, is also derived. copyright 1997 The American Physical Society

  10. Diffractive bremsstrahlung at high-β{sup *} LHC. Case study

    Energy Technology Data Exchange (ETDEWEB)

    Chwastowski, Janusz J.; Czekierda, Sabina; Staszewski, Rafal; Trzebinski, Maciej [The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland)

    2017-04-15

    Feasibility studies of the measurement of the exclusive diffractive bremsstrahlung cross-section in proton-proton scattering at the centre of mass energy of 13 TeV at the LHC are reported. Present studies were performed for the low luminosity LHC running with the betatron function value of 90 m using the ATLAS associated forward detectors ALFA and ZDC. A simplified approach to the event simulation and reconstruction is used. The background influence is also discussed. (orig.)

  11. The effect of magnetic field strength on the time evolution of high energy bremsstrahlung radiation created by an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ropponen, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)], E-mail: tommi.ropponen@phys.jyu.fi; Tarvainen, O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Jones, P.; Peura, P.; Kalvas, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland); Suominen, P. [Prizztech Ltd/Magnet Technology Centre, Tiedepuisto 4, FI-28600 Pori (Finland); Koivisto, H.; Arje, J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)

    2009-03-11

    An electron cyclotron resonance (ECR) ion source is one of the most used ion source types for high charge state heavy ion production. In ECR plasma the electrons are heated by radio frequency microwaves in order to provide ionization of neutral gases. As a consequence, ECR heating also generates very high electron energies (up to MeV region) which can produce a vast amount of bremsstrahlung radiation causing problems with radiation shielding and heating superconducting cryostat of an ECR ion source. To gain information about the time evolution of the electron energies in ECR plasma radial bremsstrahlung measurements were performed. JYFL 14 GHz ECR ion source was operated in pulsed mode and time evolution measurements were done with different axial magnetic field strengths with oxygen and argon plasmas. Bremsstrahlung data were analyzed with a time interval of 2 ms yielding information at unprecedented detail about the time evolution of high energy bremsstrahlung radiation from an ECR ion source. It was observed, for example, that reaching the steady state phase of the plasma bremsstrahlung requires several hundred milliseconds and the steady state time can be different with different gases.

  12. Experimental and analytical study of the bremsstrahlung radiation production at low energies

    International Nuclear Information System (INIS)

    Moran, P.; Gonzales, L.; Delgado, V.; Lopez, A.; Vano, E.

    1986-01-01

    The bremsstrahlung photon beam from an X-ray tube with chromium anode has been studied, for an electron energy of 60 Kev. In the experimental step, a new measurement method has been developed. This is based on the detection and measurement of the fluorescence produced when the photons from the tube impinge on targets which are used as calibrated flux monitors. The composition and physical characteristics of the targets are well-known. In the steps of experimental data treatment, an analytical study of the theoretical models describing thick target bremsstrahlung yield is performed. A factorization which accounts for the elemental physical processes is obtained, employing simple mathematical functions. The characteristic parameters found in the numerical fit process lead to results in good agreement with the experimental observations from other authors and predict theoretical exposure values in perfect agreement with the exposures measured for X-ray beams generated in several operating conditions. (author)

  13. Impact of internal bremsstrahlung on the detection of γ rays from neutralinos

    International Nuclear Information System (INIS)

    Cannoni, M.; Gomez, M. E.; Sanchez-Conde, M. A.; Prada, F.; Panella, O.

    2010-01-01

    We present a detailed study of the effect of internal bremsstrahlung photons in the context of the minimal supersymmetric standard models and their impact on γ-ray dark matter annihilation searches. We find that, although this effect has to be included for the correct evaluation of fluxes of high energy photons from neutralino annihilation, its contribution is relevant only in models and at energies where the lines contribution is dominant over the secondary photons. Therefore, we find that the most optimistic supersymmetric scenarios for dark matter detection do not change significantly when including the internal bremsstrahlung. As an example, we review the γ-ray dark matter detection prospects of the Draco dwarf spheroidal galaxy for the MAGIC stereoscopic system and the CTA project. Though the flux of high energy photons is enhanced by an order of magnitude in some regions of the parameter space, the expected fluxes are still much below the sensitivity of the instruments.

  14. Few body problems in nuclear and particle physics

    International Nuclear Information System (INIS)

    Slobodrian, R.J.; Cujec, B.; Ramavataram, K.

    1975-01-01

    Nucleon-nucleon interactions at all energies, meson-nucleon and meson-deuteron interactions, nuclear bremsstrahlung, on-shell and off-shell interactions, final-state interactions, bound and scattering states, few-body forces, polarization phenomena, short range correlations, quasi-free scattering, composite hadron models, subnucleon structure, multiparticle and coherent production processes, break-up reactions, electrodisintegration, relativistic effects and future resources in nuclear and particle physics are discussed in relation to the state of few-body physics in 1974. (B.F.G.)

  15. ''Atomic'' Bremsstrahlung or polarizational radiation in collision of many-electron ions

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Solov'yov, A.V.

    1991-01-01

    In this work the so-called ''Atomic'' bremsstrahlung (AB) or polarizational radiation, created in collisions of atoms or ions, is discussed. This kind of radiation arises due to the polarization of the electron shell of colliding particles. It is created by the structured projectiles and targets if the constituents are electrically charged. 6 refs, 2 figs

  16. Zadig: latest improvements to Bremsstrahlung treatment and in-flight annihilation scheme; Zadig: amelioration du traitement Bremsstrahlung et traitement de l'annihilation en vol

    Energy Technology Data Exchange (ETDEWEB)

    Menard, St

    2006-07-01

    Multigroup cross-section for the 3-dimensional Monte-Carlo transport code DIANE are produced by the ZADIG code. Although DIANE does not transport the electrons and positrons, the production of Bremsstrahlung photons induced by the electrons and positrons during their slowing down is taken into account in the ZADIG code because the electron-gamma cascade is an important process in high energy gamma ray transport. ZADIG does not distinguish positrons from electrons except for the positron annihilation. However, the user can turn on this direction. This report presents the latest improvements to the Bremsstrahlung model of ZADIG and to the positron annihilation algorithm implemented in the code. Positrons can annihilate either in flight or at rest in the latest release of ZADIG. As MCNP does not take into account the annihilation in flight, results of ZADIG-DIANE calculations are compared to the results of GEANT-4 in order to validate the annihilation scheme of ZADIG. The results with annihilation divided by the results without present similar trends between 0.6 and 10 MeV for the 2 codes (GEANT-4 and ZADIG-DIANE), in other words an influence of 5%, so the annihilation scheme programmed in ZADIG appears to be satisfying and can be considered as validated.

  17. Spatial distribution of bremsstrahlung in water and water-iron by 22-MeV electron bombardment measured with activation detectors

    International Nuclear Information System (INIS)

    Nakamura, Takashi; Nishimoto, Takanao; Hirayama, Hideo.

    1977-01-01

    The spatial distributions of bremsstrahlung in water (1 m thick) and water (60 cm thick)-iron (6.3 cm thick) bombarded by 22-MeV electrons were measured by using a new activation method which we developed. These informations are useful for studying shielding, residual activity and radiation damage of accelerator and target materials. From the measured activities, the bremsstrahlung spectra in water were evaluated with the LYRA and the SAND-II unfolding codes. The evaluated spectra were in good agreement with the analytical calculation by the DIBRE code, except for the higher energy ends. The longitudinal and the lateral distributions of bremsstrahlung flux in water were obtained by integrating the evaluated spectra above 8 MeV. The agreement of the experimental and the calculated flux distributions was very good except for a large angle to beam direction. The total photon number crossing a plane normal to the beam axis attenuates exponentially along the axial depth. The iso-flux contour of bremsstrahlung flux was given by interpolating the flux distribution curves. Only the saturated activities of gold detectors were obtained for water-iron in good experimental accuracy. The spatial distribution of gold saturated activities in water-iron clearly shows the attenuating effect due to strong absorption in iron. (auth.)

  18. Measuring probe for a nuclear reactor

    International Nuclear Information System (INIS)

    Overhoff, T.

    1976-01-01

    A coaxial cable is helically wound into two concentric coils, forming the one end of the probe. At the other end of the probe, the inner conductor's ends are wired to the outer conducter's two extremities by a conductor made of a material with low neutron and gamma interaction cross-section. The direct current produced by this self-powered detector is frequency filtered in order to separate the contributions of the neutron induced secondary-electrons from the photo-electrons, and from the thermally excited conduction electrons. Neutron and gamma fluxes, as well as temperature are therefore determined by using a single probe. (RW) [de

  19. A collimator optimization method for quantitative imaging: application to Y-90 bremsstrahlung SPECT.

    Science.gov (United States)

    Rong, Xing; Frey, Eric C

    2013-08-01

    Post-therapy quantitative 90Y bremsstrahlung single photon emission computed tomography (SPECT) has shown great potential to provide reliable activity estimates, which are essential for dose verification. Typically 90Y imaging is performed with high- or medium-energy collimators. However, the energy spectrum of 90Y bremsstrahlung photons is substantially different than typical for these collimators. In addition, dosimetry requires quantitative images, and collimators are not typically optimized for such tasks. Optimizing a collimator for 90Y imaging is both novel and potentially important. Conventional optimization methods are not appropriate for 90Y bremsstrahlung photons, which have a continuous and broad energy distribution. In this work, the authors developed a parallel-hole collimator optimization method for quantitative tasks that is particularly applicable to radionuclides with complex emission energy spectra. The authors applied the proposed method to develop an optimal collimator for quantitative 90Y bremsstrahlung SPECT in the context of microsphere radioembolization. To account for the effects of the collimator on both the bias and the variance of the activity estimates, the authors used the root mean squared error (RMSE) of the volume of interest activity estimates as the figure of merit (FOM). In the FOM, the bias due to the null space of the image formation process was taken in account. The RMSE was weighted by the inverse mass to reflect the application to dosimetry; for a different application, more relevant weighting could easily be adopted. The authors proposed a parameterization for the collimator that facilitates the incorporation of the important factors (geometric sensitivity, geometric resolution, and septal penetration fraction) determining collimator performance, while keeping the number of free parameters describing the collimator small (i.e., two parameters). To make the optimization results for quantitative 90Y bremsstrahlung SPECT more

  20. Mott scattering as a probe of long range QCD

    International Nuclear Information System (INIS)

    Bertulani, C.A.; Balantekin, A.B.

    1993-12-01

    We investigate the possibility of using the Mott scattering between identical nuclei to assess the existence of long range QCD, e.g., a color Van der Waals interaction, as suggested recently. Among other effects which were not considered before, the tail of the nuclear potential, emission of radiation by Bremsstrahlung, atomic screening, emission of delta-electrons, and the quasi-molecule binding are included in our calculations. We show that the sum of these effects can explain the observed shift in the Mott oscillations in a recent experiment. (orig.)

  1. Polarization of Bremsstrahlung; Polarisation du rayonnement de freinage

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1957-07-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [French] Le taux de polarisation d'un spectre de rayonnement de freinage est calcule pour une cible d'epaisseur finie en tenant compte de la diffusion multiple des electrons dans la cible. Les courbes sont tracees pour les electrons incidents d'energie 25 MeV, pour differentes energies de photons, et a differents angles. (auteur)

  2. Gamma-ray imaging probes

    International Nuclear Information System (INIS)

    Wild, W.J.

    1988-01-01

    External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work

  3. Determination of the temperature of bremsstrahlung photon generated by ultraintense laser using various thickness attenuators

    International Nuclear Information System (INIS)

    Hasegawa, Shuichi; Takashima, Ryuta; Todoriki, Masaru; Kikkawa, Satoshi; Soda, Keita; Takano, Kei; Oishi, Yuji; Nayuki, Takuya; Fujii, Takashi; Nemoto, Koshichi

    2011-01-01

    We evaluate the simplified method using the Lambert-Beer law to measure the temperature of bremsstrahlung photon generated by an ultraintense laser. Analytical values are compared to the results of the Monte Carlo calculation of GEANT4 and they agreed very well on the condition of the appropriate distance between the attenuator and the detector. We performed the experiment to measure the temperature of bremsstrahlung x-ray emitted from a metal target irradiated by a Ti:sapphire laser with 76 mJ, 72 fs, 2.2 x 10 18 W/cm 2 . For a Cu target of 30 μm thick, the photon temperature was reasonably determined to be 0.18 MeV, which is in good agreement with previous studies.

  4. Y-90 SPECT ML image reconstruction with a new model for tissue-dependent bremsstrahlung production using CT information: a proof-of-concept study

    Science.gov (United States)

    Lim, Hongki; Fessler, Jeffrey A.; Wilderman, Scott J.; Brooks, Allen F.; Dewaraja, Yuni K.

    2018-06-01

    While the yield of positrons used in Y-90 PET is independent of tissue media, Y-90 SPECT imaging is complicated by the tissue dependence of bremsstrahlung photon generation. The probability of bremsstrahlung production is proportional to the square of the atomic number of the medium. Hence, the same amount of activity in different tissue regions of the body will produce different numbers of bremsstrahlung photons. Existing reconstruction methods disregard this tissue-dependency, potentially impacting both qualitative and quantitative imaging of heterogeneous regions of the body such as bone with marrow cavities. In this proof-of-concept study, we propose a new maximum-likelihood method that incorporates bremsstrahlung generation probabilities into the system matrix, enabling images of the desired Y-90 distribution to be reconstructed instead of the ‘bremsstrahlung distribution’ that is obtained with existing methods. The tissue-dependent probabilities are generated by Monte Carlo simulation while bone volume fractions for each SPECT voxel are obtained from co-registered CT. First, we demonstrate the tissue dependency in a SPECT/CT imaging experiment with Y-90 in bone equivalent solution and water. Visually, the proposed reconstruction approach better matched the true image and the Y-90 PET image than the standard bremsstrahlung reconstruction approach. An XCAT phantom simulation including bone and marrow regions also demonstrated better agreement with the true image using the proposed reconstruction method. Quantitatively, compared with the standard reconstruction, the new method improved estimation of the liquid bone:water activity concentration ratio by 40% in the SPECT measurement and the cortical bone:marrow activity concentration ratio by 58% in the XCAT simulation.

  5. Comparison of Techniques to Reduce Bremsstrahlung Background Radiation from Monoenergetic Photon Beams

    International Nuclear Information System (INIS)

    Johnson, M; McNabb, D

    2006-01-01

    An important applied technology is a tunable mono-energetic photon source [1]. These sources are made of relativistic electron accelerators coupled to low-energy lasers, which produce high-energy, mono-energetic-rays. One challenge associated with systems such as this is a continuum of bremsstrahlung background created when an electron beam passes through an aperture of some sort and the electron bunch or its halo impinges on the aperture pictured in figure 1. For instance, in the current T-REX [1] design for the interaction point between the laser- and electron-beam, the electron-beam passes through the center of a mirror used to reflect the laser. There is a potential with this design that bremsstrahlung radiation may be produced at the edges of the mirror openings and contaminate the mono-energetic photon beam. Certain applications [2] may be sensitive to this contamination. To reduce the bremsstrahlung contaminate a collimator (thickness ∼24in. (calculated from XCOM database [3]) to attenuate by a factor of 10 -3 the 112MeV photons expected in the T-REX demonstration [1]) is situated between the aperture and target. To maximize the brightness of the photon-beam, the collimator opening must be no less than the size of the photon-beam spot size expected to be about 1mm. This fixes the collimator opening. a priori the aperture size must be greater than the collimator opening and is a function distance between the aperture and collimator. In this paper we focus on two approaches to estimate the aperture size, given a collimator and a target whose sizes and distances from the aperture are given. In the next section we will discuss these approaches

  6. Feasibility studies of a polarized positron source based on the Bremsstrahlung of polarized electrons

    International Nuclear Information System (INIS)

    Dumas, J.

    2011-09-01

    The nuclear and high-energy physics communities have shown a growing interest in the availability of high current, highly-polarized positron beams. A sufficiently energetic polarized photon or lepton incident on a target may generate, via Bremsstrahlung and pair creation within a solid target foil, electron-positron pairs that should carry some fraction of the initial polarization. Recent advances in high current (> 1 mA) spin polarized electron sources at Jefferson Lab offer the perspective of creating polarized positrons from a low energy electron beam. This thesis discusses polarization transfer from electrons to positrons in the perspective of the design optimization of a polarized positron source. The PEPPo experiment, aiming at a measurement of the positron polarization from a low energy (< 10 MeV) highly spin polarized electron beam is discussed. A successful demonstration of this technique would provide an alternative scheme for the production of low energy polarized positrons and useful information for the optimization of the design of polarized positron sources in the sub-GeV energy range. (author)

  7. Classical and quantum theories of the polarization bremsstrahlung in the local electron density model

    International Nuclear Information System (INIS)

    Astapenko, V.A.; Bureeva, L.A.; Lisitsa, V.S.

    2000-01-01

    Classical and quantum theories of polarization bremsstrahlung in a statistical (Thomas-Fermi) potential of complex atoms and ions are developed. The basic assumptions of the theories correspond to the approximations employed earlier in classical and quantum calculations of ordinary bremsstrahlung in a static potential. This makes it possible to study on a unified basis the contribution of both channels in the radiation taking account of their interference. The classical model makes it possible to obtain simple universal formulas for the spectral characteristics of the radiation. The theory is applied to electrons with moderate energies, which are characteristic for plasma applications, specifically, radiation from electrons on the argon-like ion KII at frequencies close to its ionization potential. The computational results show the importance of taking account of the polarization channel of the radiation for plasma with heavy ions

  8. Internal Bremsstrahlung spectrum of 204TI in the X-ray region

    International Nuclear Information System (INIS)

    Raghavendra, M.K.; Ramaswamy, C.R.

    2001-01-01

    The internal Bremsstrahlung spectrum from 204 TI has been measured, using magnetic deflector method, in the X-ray region. The corrected spectral intensity is compared with the Coulomb-corrected KUB theory in the energy region of 10 to 30 keV. The good agreement between experiment and theory in this energy region, suggests that 'detour effects' are negligible in the low energy region. (author)

  9. Simultaneous investigation of parent electrons and bremsstrahlung x rays by rocket-borne detectors

    International Nuclear Information System (INIS)

    Vij, K.K.; Venkatesan, D.; Sheldon, W.R.; Kern, J.W.; Benbrook, J.R.; Whalen, B.A.

    1975-01-01

    Simultaneous measurements of the energy spectrum of precipitating electrons and the resulting bremsstrahlung X ray spectrum were carried out during an auroral event on March 3, 1971, at the Churchill Research Range, Manitoba, Canada. The electron data were obtained with detectors on a Black Brant VB sounding rocket (275-km apogee), while the X ray flux was measured by an instrument package that was boosted to 60 km on an Arcas rocket. The X ray package was deployed on a parachute at apogee to provide a slow descent through the atmosphere. Thick target bremsstrahlung theory is used to calculate the X ray flux produced by the incident electrons, and a Monte Carlo method is used to predict the X ray spectrum at various altitudes appropriate for comparison with the measured X ray data. Satisfactory agreement between theory and experiment is obtained, and the value of the constant in the thick target theory has been estimated to be (2plus-or-minus0.5) times10 -5

  10. Simultaneous investigation of parent electrons and bremsstrahlung x rays by Rocket--Borne detectors

    International Nuclear Information System (INIS)

    Vij, K.K.; Venkatesan, D.; Sheldon, W.R.; Kern, J.W.; Benbrook, J.R.; Whalen, B.A.

    1975-01-01

    Simultaneous measurements of the energy spectrum of precipitating electrons and the resulting bremsstrahlung X ray spectrum were carried out during an auroral event on March 3, 1971, at the Churchill Research Range, Manitoba, Canada. The electron data were obtained with detectors on a Black Brant VB sounding rocket (275-km apogee), while the X ray flux was measured by an instrument package that was boosted to 60 km on an Arcas rocket. The X ray package was deployed on a parachute apogee to provide a slow descent through the atmosphere. Thick target bremsstrahlung theory is used to calculate the X ray flux produced by the incident electrons, and a Monte Carlo method is used to predict the X ray spectrum at various altitudes appropriate for comparison with the measured X ray data. Satisfactory agreement between theory and experiment is obtained, and the value of the constant in the thick target theory has been estimated to be (2plus-or-minus0.5) times10 -5 . (auth)

  11. Probing nuclear structure with nucleons; Sonder la structure nucleaire avec des nucleons

    Energy Technology Data Exchange (ETDEWEB)

    Bauge, E. [CEA Bruyeres-le-Chatel, Service de Physique Nucl aire, 91 (France)

    2007-07-01

    The goal of this lecture is to show how nucleon scattering can be used to probe the structure of target nuclei, and how nucleon scattering observables can be interpreted in terms of nuclear structure using microscopic optical potentials. After a brief overview of the specificities of nucleon-nucleus scattering, and a quick reminder on scattering theory, the main part of this lecture is devoted to the construction of optical potentials in which the target nuclei structure information is folded with an effective interaction. Several examples of such microscopic optical model potentials are given. (author)

  12. Study of Diffractive Bremsstrahlung at 13 TeV LHC

    CERN Document Server

    Czekierda, Sabina

    2016-01-01

    Feasibility studies of the diffractive bremsstrahlung measurement at the LHC at $\\sqrt s$ = 13 TeV are presented. The method considered for this measurement uses the ATLAS detector and, in particular, the Zero Degree Calorimeter and the ATLAS Forward Proton detectors. The signal and background processes were generated with GenEx and PYTHIA 8.2 generators, respectively. The obtained fiducial cross sections are 1.2 ub for the signal and 6 ub for the background. Further reduction of the background is possible by the optimisation of event selection cuts.

  13. Powerful accelerators for bremsstrahlung and electron beams generation on the basis of inductive energy-storage elements

    Energy Technology Data Exchange (ETDEWEB)

    Diyankov, V S; Kovalev, V P; Kormilitsin, A I; Lavrentev, B N [All-Russian Research Institute of Technical Physics, Snezhinsk (Russian Federation)

    1997-12-31

    The report summarizes RFNC-VNIITF activities from 1963 till 1995, devoted to the development of pulsed electron accelerators on the basis of inductive energy storage with electroexplosive wires. These accelerators are called IGUR. The activities resulted in the development of a series of generators of powerful radiation being cheap and easy in manufacturing and servicing. The accelerators achieved the following maximum parameters: diode voltage up to 6 MV, diode current up to 80 kA, current of the extracted electron beam 30 kA, density of the extracted electron beam energy 500 J/cm{sup 2}, bremsstrahlung dose 250000 Rads, and bremsstrahlung dose rate 10{sup 13} Rads/sec. (author). 3 tabs., 5 figs., 7 refs.

  14. Powerful accelerators for bremsstrahlung and electron beams generation on the basis of inductive energy-storage elements

    International Nuclear Information System (INIS)

    Diyankov, V.S.; Kovalev, V.P.; Kormilitsin, A.I.; Lavrentev, B.N.

    1996-01-01

    The report summarizes RFNC-VNIITF activities from 1963 till 1995, devoted to the development of pulsed electron accelerators on the basis of inductive energy storage with electroexplosive wires. These accelerators are called IGUR. The activities resulted in the development of a series of generators of powerful radiation being cheap and easy in manufacturing and servicing. The accelerators achieved the following maximum parameters: diode voltage up to 6 MV, diode current up to 80 kA, current of the extracted electron beam 30 kA, density of the extracted electron beam energy 500 J/cm 2 , bremsstrahlung dose 250000 Rads, and bremsstrahlung dose rate 10 13 Rads/sec. (author). 3 tabs., 5 figs., 7 refs

  15. Excitation of spin-1 states in 166168170Er using bremsstrahlung

    International Nuclear Information System (INIS)

    Metzger, F.R.

    1976-01-01

    Some 40 states in 166 , 168 , 170 Er, most of them previously unknown, have been excited using bremsstrahlung with < or =4.2 MeV endpoint energy. For all but three of these levels, the angular distribution of the resonantly scattered radiation favors the assignment of spin 1. For some of the strongly excited levels, linear polarization measurements have been performed. They indicate that these levels have positive parity. The branching ratios further characterize them as K=1 excitations

  16. Possibility of some radionuclides production using high energy electron Bremsstrahlung

    International Nuclear Information System (INIS)

    Balzhinnyam, N.; Belov, A.G.; Gehrbish, Sh; Maslov, O.D.; Shvetsov, V.N.; Ganbold, G.

    2008-01-01

    The method of some radionuclides production using high energy Bremsstrahlung of electron accelerators and determination of photonuclear reaction yield and specific activities for some radionuclides is described. Photonuclear reaction yield and specific activities for some radionuclides are determined for 117m Sn, 111 In and 195m Pt. Based on the experimental data obtained at low energy (E e- e- = 75 MeV) of the IREN facility (FLNR, JINR) at irradiation of high purity platinum and tin metals

  17. Probing N=2 superconformal field theories with localization

    Energy Technology Data Exchange (ETDEWEB)

    Fiol, Bartomeu [Departament de Física Fonamental i Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain); Garolera, Blai [Escuela de Física, Universidad de Costa Rica,11501-2060 San José (Costa Rica); Torrents, Genís [Departament de Física Fonamental i Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain)

    2016-01-27

    We use supersymmetric localization to study probes of four dimensional Lagrangian N=2 superconformal field theories. We first derive a unique equation for the eigenvalue density of these theories. We observe that these theories have a Wigner eigenvalue density precisely when they satisfy a necessary condition for having a holographic dual with a sensible higher-derivative expansion. We then compute in the saddle-point approximation the vacuum expectation value of 1/2-BPS circular Wilson loops, and the two-point functions of these Wilson loops with the Lagrangian density and with the stress-energy tensor. This last computation also provides the corresponding Bremsstrahlung functions and entanglement entropies. As expected, whenever a finite fraction of the matter is in the fundamental representation, the results are drastically different from those of N=4 supersymmetric Yang-Mills theory.

  18. Determination of the parametric region in which runaway electron energy losses are dominated by bremsstrahlung radiation in tokamaks

    International Nuclear Information System (INIS)

    Fernandez-Gomez, I.; Martin-Solis, J. R.; Sanchez, R.

    2007-01-01

    It has been recently argued that, at sufficiently large parallel electric fields, bremsstrahlung radiation can greatly reduce the maximum energy that runaway electrons can gain in tokamaks [M. Bakhtiari et al., Phys. Plasmas 12, 102503 (2005)]. In this contribution, the work of these authors is extended to show that the region where bremsstrahlung radiation dominate runaway energy losses is however more restricted than reported by them. Expressions will be provided for the limits of this region within the parameter space spanned by the background density and parallel electric field, as a function of the rest of the plasma parameters. It will be shown that the background density has to be above a certain critical value and that the parallel electric field must lie within a range of values, below and above which synchrotron radiation dominate the runaway energy losses. Finally, it will be demonstrated that typical disruption parameters lie within this region and, as a result, bremsstrahlung losses still play an important role in controlling the runaway energy

  19. Long-term measurement with calorimetric probes at unit 1 of V-1 nuclear power plant

    International Nuclear Information System (INIS)

    Erben, O.; Szasz, Z.; Jirousek, V.; Teren, S.

    1989-01-01

    Two calorimetric probes were tested at the first unit of the Bohunice V-1 nuclear power plant in long-term operation, i.e., during one whole reactor duty time. Each probe consisted of five fission calorimeters and one compensation calorimeter with a tungsten body. The actual calorimeters were provided with jacketed thermocouples 0.5 mm indiameter and 19 m in length. A detailed description is presented of the measuring chains and measurement techniques. Also described is the method of the disposal of the irradiated probes. The method is presented of the evaluation of measured data and the results are discussed of the analysis of these data. The measurements, including measurements during reactor shut-down and the results of the analysis of the measured data proved good viability and stability of the used calorimetres. The method of measuring the thermocouple signals is simple and the in-service evaluation of required data is quick. In order to increase measurement efficiency it would be appropriate to complete the measuring chain and to automate it. Reliability is a affected merely by protecting the thermocouples against mechanical damage during measurement probe handling and on the reactor. (Z.M.). 5 figs., 5 tabs., 5 refs

  20. Coherent bremsstrahlung in crystals as a tool for producing high energy photon beams to be used in photoproduction experiments at CERN SPS

    Energy Technology Data Exchange (ETDEWEB)

    Bilokon, H; D' Ettorre Piazzoli, B; Mannocchi, G [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati); Bologna, G; Picchi, P [Turin Univ. (Italy). Ist. di Fisica Generale; Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati); Celani, F; Falcioni, R [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati

    1983-01-01

    We recall the properties of coherent bremsstrahlung of high energy electrons in single crystals and show that a suitably oriented diamond crystal can produce a high energy bremsstrahlung beam whose quasimonochromatic spectral composition may be exploited for increasing the production rate in a photoproduction experiment at hundreds of GeV. A careful analysis of the required angular resolutions is performed. It turns out that the standard deviation of the electron beam angular divergence in one plane should be less than 0.3 mrad, for a beam energy of 150 GeV. The standard deviation in the perpendicular plane is not critical. In this situation the photoproduction rate in a typical case is increased by a factor of about 3 with respect to the conventional bremsstrahlung beam.

  1. New microfocus bremsstrahlung source based on betatron B-18 for high-resolution radiography and tomography

    Science.gov (United States)

    Rychkov, M. M.; Kaplin, V. V.; Malikov, E. L.; Smolyanskiy, V. A.; Stepanov, I. B.; Lutsenko, A. S.; Gentsel'man, V.; Vas'kovskiy, I. K.

    2018-01-01

    New microfocus source of hard bremsstrahlung (photon energy > 1 MeV), based on the betatron B-18 with a narrow Ta target inside, for high-resolution radiography and tomography is presented. The first studies of the source demonstrate its possibilities for practical applications to detect the microdefects in products made from heavy materials and to control gaps in joints of parts of composite structures of engineering facilities. The radiography method was used to investigate a compound object consisting of four vertically arranged steel bars between which surfaces were exposed gaps of 10 μm in width. The radiographic image of the object, obtained with a magnification of 2.4, illustrates the good sensitivity of detecting the gaps between adjacent bars, due to the small width of the linear focus of the bremsstrahlung source.

  2. Nuclear reactor vessel surface inspecting technique applying electric resistance probe

    International Nuclear Information System (INIS)

    Yamaguchi, T.; Enami, K.; Yoshioka, M.

    1975-01-01

    A new technique for inspecting the inner surface of the PWR type nuclear reactor vessel by use of an electric resistance probe is introduced, centering on a data processing system. This system is composed of a mini-computer, a system typewriter, an interface unit, a D-A converter and controller, and X-Y recorder and others. Its functions are judging flaws and making flaw detection maps. In order to judge flaws by flaw detection signals, three kinds of flaw judging methods have been developed. In case there is a flaw, its position and depth are calculated and listed on the system typewriter. The flaw detection maps are expressed in four kinds of modes and they are displayed on the X-Y recorder. (auth.)

  3. A new detection method of 99Tc by nuclear excitation

    International Nuclear Information System (INIS)

    Sekine, T.; Yoshihara, Kenji; Nemeth, Zs.; Lakosi, L.; Veres, A.

    1989-01-01

    A new nuclear excitation process, 99 Tc(γ,γ') 99m Tc reaction, was applied for the first time to radioactivation analysis of technetium. Bremsstrahlung irradiation of 99 Tc samples gave the reaction product 99m Tc which emits γ-ray easily measurable by a semiconductor detector. The production rate of 99m Tc per μg 99 Tc was linearly correlated with the flux of bremsstrahlung. The detection limit of 99 Tc was estimated to be nanogram order (0.63 Bq 99 Tc) under the optimum irradiation condition. Possible interference by 100 Ru(γ, p) 99m Tc reaction was also studied, which could be discriminated from the (γ,γ') reaction by simultaneously occurring 98 Ru(γ,p) 97 Ru reaction. (author) 17 refs.; 7 figs

  4. Polarimetry of coherent bremsstrahlung by analysis of the photon energy spectrum

    International Nuclear Information System (INIS)

    Darbinyan, S.; Hakobyan, H.; Jones, R.; Sirunyan, A.; Vartapetian, H.

    2005-01-01

    A method of coherent bremsstrahlung (CB) polarimetry based on the analysis of the shape of the photon energy spectrum is presented. The influence of a number of uncertainty sources, including the choice of atomic form-factors, has been analyzed. For a CB source consisting of a diamond radiator and multi-GeV electrons, an absolute accuracy of polarimetry at the level of 0.01-0.02 is attainable

  5. Probing reaction dynamics with GDR decay

    International Nuclear Information System (INIS)

    Beene, J.R.

    1994-01-01

    The giant dipole resonance (GDR) has been a prolific source of information on the physics of the nucleus. Mostly it has taught us about nuclear structure, but recently experiments have utilized the GDR as a probe of nuclear reaction dynamics. In this report two examples of such investigations are discussed involving very different reactions and probing time scales that differ by a factor of ∼10 3

  6. Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source

    International Nuclear Information System (INIS)

    Kumar, Narender; Rodrigues, G.; Lakshmy, P. S.; Mathur, Y.; Ahuja, R.; Kanjilal, D.; Baskaran, R.

    2014-01-01

    A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the “off-resonance” mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied

  7. Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Narender; Rodrigues, G., E-mail: gerosro@gmail.com; Lakshmy, P. S.; Mathur, Y.; Ahuja, R.; Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi (India); Baskaran, R. [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India)

    2014-02-15

    A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the “off-resonance” mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied.

  8. Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source.

    Science.gov (United States)

    Kumar, Narender; Rodrigues, G; Lakshmy, P S; Baskaran, R; Mathur, Y; Ahuja, R; Kanjilal, D

    2014-02-01

    A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the "off-resonance" mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied.

  9. Monitoring of right ventricular function by single probe system (nuclear stethoscope) and sup(81m)Kr

    International Nuclear Information System (INIS)

    Nishimura, Tsunehiko; Uehara, Toshiisa; Hayashida, Kohei; Ohmine, Hiromi; Kimura, Motomasa

    1982-01-01

    A single probe system (nuclear stethoscope) was developed to evaluate the monitoring of right ventricular function by sup(81m)Kr continuous infusion method. Optimal right ventricular and background positions were determined by position/monitor mode on beat-to-beat basis, and right ventricular ejection fraction (RVEF) was calculated by multi-gated method (MUGA). The correlation coefficient of nuclear stethoscope RVEF and camera-computer RVEF (MUGA) was 0.82, while the correlation coefficient of nuclear stethoscope RVEF and camera-computer RVEF (first-pass method) was 0.64. Therefore, the RVEF by nuclear stethoscope is useful for monitoring of right ventricular function. Clinical applications by sup(81m)Kr and nuclear stethoscope were as follows. 1. Exercise/rest RVEF is an extremely sensitive indicator to discriminate coronary artery disease (RCA occlusion) from normal subjects. 2. Beat-to-beat right ventricular volume response is useful for the monitoring of arrythmia such as atrial fibrillation. (author)

  10. Monitoring of right ventricular function by single probe system (nuclear stethoscope) and sup(81m)Kr

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Tsunehiko; Uehara, Toshiisa; Hayashida, Kohei; Ohmine, Hiromi; Kimura, Motomasa [National Cardiovascular Center, Suita, Osaka (Japan)

    1982-12-01

    A single probe system (nuclear stethoscope) was developed to evaluate the monitoring of right ventricular function by sup(81m)Kr continuous infusion method. Optimal right ventricular and background positions were determined by position/monitor mode on beat-to-beat basis, and right ventricular ejection fraction (RVEF) was calculated by multi-gated method (MUGA). The correlation coefficient of nuclear stethoscope RVEF and camera-computer RVEF (MUGA) was 0.82, while the correlation coefficient of nuclear stethoscope RVEF and camera-computer RVEF (first-pass method) was 0.64. Therefore, the RVEF by nuclear stethoscope is useful for monitoring of right ventricular function. Clinical applications by sup(81m)Kr and nuclear stethoscope were as follows. 1. Exercise/rest RVEF is an extremely sensitive indicator to discriminate coronary artery disease (RCA occlusion) from normal subjects. 2. Beat-to-beat right ventricular volume response is useful for the monitoring of arrythmia such as atrial fibrillation.

  11. Vector dark matter annihilation with internal bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Bambhaniya, Gulab, E-mail: gulab@prl.res.in [Physical Research Laboratory, Ahmedabad 380009 (India); Kumar, Jason, E-mail: jkumar@hawaii.edu [Department of Physics & Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Marfatia, Danny, E-mail: dmarf8@hawaii.edu [Department of Physics & Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Nayak, Alekha C., E-mail: acnayak@iitk.ac.in [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India); Tomar, Gaurav, E-mail: tomar@prl.res.in [Physical Research Laboratory, Ahmedabad 380009 (India)

    2017-03-10

    We consider scenarios in which the annihilation of self-conjugate spin-1 dark matter to a Standard Model fermion–antifermion final state is chirality suppressed, but where this suppression can be lifted by the emission of an additional photon via internal bremsstrahlung. We find that this scenario can only arise if the initial dark matter state is polarized, which can occur in the context of self-interacting dark matter. In particular, this is possible if the dark matter pair forms a bound state that decays to its ground state before the constituents annihilate. We show that the shape of the resulting photon spectrum is the same as for self-conjugate spin-0 and spin-1/2 dark matter, but the normalization is less heavily suppressed in the limit of heavy mediators.

  12. Gluon bremsstrahlung and elastic scattering of hadrons

    International Nuclear Information System (INIS)

    Povh, B.

    2001-01-01

    The differential and the total cross sections in high energy hadron-proton interactions give a beautiful insight in the low Q 2 structure of the nucleon. The cross section is composed of two parts: a large energy independent part corresponding to the interaction of the valence quark with the target without gluon radiation and an energy dependent part caused by gluon bremsstrahlung. The gluons are located at small transverse distances of about 0.3 fm from the valence quarks. The model with two scales, the size of the hadron (R 2 ∼ 1 fm 2 ) and the size of the gluonic cloud (r 0 2 ∼ 0.1 fm 2 ), correctly predicts the total and the differential cross sections and the behaviour of diffractive dissociation in hadronic and deep inelastic events. (orig.)

  13. Qualification Practices in Nuclear Industry: Steam Generator Eddy Current Probe Qualification

    International Nuclear Information System (INIS)

    Vavrous, M.; Gracin, R.

    2010-01-01

    Through history of nuclear power plant operation, a large number of nuclear power plant forced outages related to tube failures occurred. It resulted with large amount of repair and outage costs, what initiated implementation of regulated practice of periodical tube examination and tube condition monitoring. Purpose of examinations is to detect existing or potential tube degradations that could affect tube integrity and therefore result in forced outages and unwanted costs related to emergency repair activities and loss of ability for electrical power production. With increased examination activities, additional information about steam generator tube condition became available and additional methods for ensuring tube integrity became available. As the number of examination solutions increased, need for validation and assessment of examination methods occurred. For that purpose, a large number of standards and guidelines with its requirements were implemented in nuclear industry regulatory requirements to ensure that adequately validated examinations are applied. With this purpose, qualification requirements for inspection activities were implemented with other requirements. With progress of technology, progress was also achieved in examination methods and more advanced examination methods and advanced inspection systems were developed. This advancement is accompanied by advancement in regulatory requirements regarding inspection and monitoring of tube integrity and condition. Ultimate goal of implementation of qualification processes and its requirements in all aspects of nuclear industry is to achieve minimal rate of forced outages, which would ensure maximum electrical power production capabilities and maximum optimization of operational costs while maintaining safe operation in accordance with environmental policies. This article will focus on qualification of steam generator eddy current bobbin probe.(author).

  14. 6th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions

    CERN Document Server

    2014-01-01

    One of the premier meetings in the field of high-energy nuclear physics, the Hard Probes conference series brings together the experimental and theoretical communities interested in the hard and electromagnetic observables related to nuclear matter at extreme temperatures and densities. Prior to the conference, the University of Cape Town will host a summer school for young physicists in the field. High energy nuclear physics focuses on the science of a trillion degrees. These temperatures were last seen in nature a microsecond after the Big Bang, but mankind recreates them thousands of times a second in particle accelerators such as CERN's Large Hadron Collider and BNL's Relativistic Heavy Ion Collider. At these temperatures, 100,000 times hotter than the center of the sun, the strong force is dominant, and we hope to learn about the fundamental and non-trivial emergent many-body dynamics of the quarks and gluons that make up 99% of the mass of the visible universe. We anticipate the usual format for the H...

  15. Study of 1s internal bremsstrahlung spectrum from 57Co

    Science.gov (United States)

    Raghavendra, M. K.; Azeez, Syed; Ramaswamy, C. R.; Umesh, T. K.; Gowda, Ramakrishna

    2002-07-01

    The internal bremsstrahlung contribution from the electron capture of 57Co has been measured in coincidence with K-X-ray of the residual atom. The end-point energy (EPE) is extracted from the data using the linearised Jauch plot. The transition energy obtained using the (EPE) is 842.7 keV, which is close to the value given by Audi and Wapstra. The measured intensity and shape factor from 300 to 600 keV are found to be in good agreement with the Glauber and Martin theory.

  16. Study of 1s internal bremsstrahlung spectrum from 57Co

    International Nuclear Information System (INIS)

    Raghavendra, M.K.; Azeez, Syed; Ramaswamy, C.R.; Umesh, T.K.; Gowda, Ramakrishna

    2002-01-01

    The internal bremsstrahlung contribution from the electron capture of 57 Co has been measured in coincidence with K-X-ray of the residual atom. The end-point energy (EPE) is extracted from the data using the linearised Jauch plot. The transition energy obtained using the (EPE) is 842.7 keV, which is close to the value given by Audi and Wapstra. The measured intensity and shape factor from 300 to 600 keV are found to be in good agreement with the Glauber and Martin theory

  17. The stonehenge technique: a new method of crystal alignment for coherent bremsstrahlung experiments

    Science.gov (United States)

    Livingston, Kenneth

    2005-08-01

    In the coherent bremsstrahlung technique a thin diamond crystal oriented correctly in an electron beam can produce photons with a high degree of linear polarization.1 The crystal is mounted on a goniometer to control its orientation and it is necessary to measure the angular offsets a) between the crystal axes and the goniometer axes and b) between the goniometer and the electron beam axis. A method for measuring these offsets and aligning the crystal was developed by Lohman et al, and has been used successfully in Mainz.2 However, recent attempts to investigate new crystals have shown that this approach has limitations which become more serious at higher beam energies where more accurate setting of the crystal angles, which scale with l/Ebeam, is required. (Eg. the recent installation of coherent bremsstrahlung facility at Jlab, with Ebeam = 6 GeV ) This paper describes a new, more general alignment technique, which overcomes these limitations. The technique is based on scans where the horizontal and vertical rotation axes of the goniometer are adjusted in a series of steps to make the normal to the crystal describe a cone of a given angle. For each step in the scan, the photon energy spectrum is measured using a tagging spectrometer, and the offsets between the electron beam and the crystal lattice are inferred from the resulting 2D plot. Using this method, it is possible to align the crystal with the beam quickly, and hence to set any desired orientation of the crystal relative to the beam. This is essential for any experiment requiring linearly polarized photons produced via coherent bremsstrahlung, and is also required for a systematic study of the channeling radiation produced by the electron beam incident on the crystal.

  18. Bremsstrahlung convertors: materials design and development

    International Nuclear Information System (INIS)

    Allred, R.E.

    1976-03-01

    An improved bremsstrahlung convertor for use at high electron beam energies was developed. The convertor consists of three main components: (1) conversion foil; (2) electron scavenger; and (3) impulse shield. Structural failures of the impulse shield were experimentally determined to be caused by shock wave interactions. Convertor materials and design modifications were aimed at attenuation of the magnitude of the shock and maximization of energy absorption by the convertor materials. Techniques proven successful included the introduction of porosity into electron scavenger and impulse shield materials, the use of a standoff between the conversion foil and the electron scavenger, the insertion of a gap between the scavenger and impulse shield, and the use of advanced composite materials for the impulse shield. These modifications have increased the convertor operating range from 4 cal/gm Au to over 8 cal/gm Au. Kevlar 49 reinforced-resin composites have proven to have the best combination of strength, stiffness, toughness, and x-ray transport properties for use as bremmstrahlung convertor impulse shields

  19. Determination of the photoeffect cross section and the K- absorption edge energy of Dy, Ta, Pt and Au atoms using Bremsstrahlung

    International Nuclear Information System (INIS)

    Garcia-Alvarez, J. A.; Lopez-Pino, N.; Diaz Rizo, O.; Corrales, Y.; Padilla-Cabal, F.; Perez-Liva, M.; D' Alessandro, K.; Maidana, N. L.

    2011-01-01

    An experiment to determine the K-shell photoelectric cross-section (CS) of Dy, Ta, Pt and Au atoms was implemented at the Nuclear Analytical Laboratory (LAN) of the InSTEC. Bremsstrahlung photons, produced by 90 Sr- 90 Y beta particles hitting a thin Ni converter, were used to irradiate the foils target of the elements under study. A HPGe detector, coupled to standard nuclear instrumentation, collected the incident and transmitted spectra. A sharp decrease in intensity at the K-shell binding energy was observed in the transmitted spectra. The photon beam divergence effects were corrected with a calibration curve calculated by means of Monte Carlo simulations (MCNPX 2.6). In order to establish accurately the CS at the K-edge energy, the obtained data was processed by two methods: fitting the total CS to a sigmoidal function, as well as the CS branches around the K edge to the empirical law σ=(A/E) n . The results were compared with experimental and theoretical values showing the best agreement when the thinner foils were used. (Author)

  20. Application of electron and Bremsstrahlung beams for composite materials processing

    International Nuclear Information System (INIS)

    Zalyubovsky, I.I.; Avilov, A.M.; Popov, G.F.; Rudychev, V.G.

    1998-01-01

    In Kharkiv University the radiation process of obtaining composite polymer materials, CPM, with high strength properties and corrosion resistance was studied. CPM are manufactured by vacuum impregnating capillary-porous materials with synthetic monomers and oligomers or by molding granular waste and resins which are further treated by relativistic electron or Bremsstrahlung beam. Such radiation treatment yields new CPM in which capillary-porous structure acting as reinforcement is filled with polymer. The results of the applied research with industrial electron accelerator in the field of thick CPM formation are presented

  1. Secondary bremsstrahlung and the energy-conservation aspects of kerma in photon-irradiated media.

    Science.gov (United States)

    Kumar, Sudhir; Nahum, Alan E

    2016-02-07

    Kerma, collision kerma and absorbed dose in media irradiated by megavoltage photons are analysed with respect to energy conservation. The user-code DOSRZnrc was employed to compute absorbed dose D, kerma K and a special form of kerma, K ncpt, obtained by setting the charged-particle transport energy cut-off very high, thereby preventing the generation of 'secondary bremsstrahlung' along the charged-particle paths. The user-code FLURZnrc was employed to compute photon fluence, differential in energy, from which collision kerma, K col and K were derived. The ratios K/D, K ncpt/D and K col/D have thereby been determined over a very large volumes of water, aluminium and copper irradiated by broad, parallel beams of 0.1 to 25 MeV monoenergetic photons, and 6, 10 and 15 MV 'clinical' radiotherapy qualities. Concerning depth-dependence, the 'area under the kerma, K, curve' exceeded that under the dose curve, demonstrating that kerma does not conserve energy when computed over a large volume. This is due to the 'double counting' of the energy of the secondary bremsstrahlung photons, this energy being (implicitly) included in the kerma 'liberated' in the irradiated medium, at the same time as this secondary bremsstrahlung is included in the photon fluence which gives rise to kerma elsewhere in the medium. For 25 MeV photons this 'violation' amounts to 8.6%, 14.2% and 25.5% in large volumes of water, aluminium and copper respectively but only 0.6% for a 'clinical' 6 MV beam in water. By contrast, K col/D and K ncpt/D, also computed over very large phantoms of the same three media, for the same beam qualities, are equal to unity within (very low) statistical uncertainties, demonstrating that collision kerma and the special type of kerma, K ncpt, do conserve energy over a large volume. A comparison of photon fluence spectra for the 25 MeV beam at a depth of  ≈51 g cm−2 for both very high and very low charged-particle transport cut-offs reveals the considerable

  2. Zeff measurements in ATF using visible bremsstrahlung

    International Nuclear Information System (INIS)

    Morita, S.; Richards, R.K.; Horton, L.D.; Isler, R.C.; Crume, E.C. Jr.; Murakami, M.

    1991-04-01

    Measurements of the effective charge Z eff in plasmas with electron cyclotron heating (ECH) and neutral beam injection (NBI) in the Advanced Toroidal Facility (ATF) have been carried out using visible bremsstrahlung. The electron temperature needed for the analysis is calculated from the measured stored energy and electron density. The value of Z eff varies widely depending on experimental conditions. In ECH plasmas it is between 2 and 8. In NBI plasmas, which are subject to radiation collapse, Z eff is between 3 and 5 at the time the stored energy reaches a maximum. However, Z eff is less than 2.5 in quasi-steady medium-density plasmas and is close to 1.2 in the highest-density plasmas, where the average electron density bar n e is of the order of 10 14 cm -3 . 12 refs., 29 figs., 1 tab

  3. Measurement of parity violation in the photodisintegration of deuterium and in the production of Bremsstrahlung on tantalum

    International Nuclear Information System (INIS)

    Earle, E.D.; McDonald, A.B.; Kidner, S.H.; Clifford, E.T.H.; Hill, J.J.; Keech, G.H.; Chupp, T.E.; Schneider, M.B.

    1987-01-01

    The circular polarization dependent component of the total cross section for photodisintegration of deuterium has been measured to be (2.7±2.8) x 10 -6 for Bremsstrahlung with an end point of 4.1 MeV and (7.7±5.3) x 10 -6 for an end point of 3.2 MeV. The helicity dependent component of the total cross section for the production of Bremsstrahlung on tantalum by longitudinally polarized electrons has been measured to be (0.63±0.70) x 10 -6 for an electron energy of 4.1 MeV and (3.1±1.5) x 10 -6 at 3.2 MeV. All measurements are in agreement with theoretical predictions for these processes. (author)

  4. On the possibility of a quantum bremsstrahlung induced self-modulation of a relativistic beam channeling in crystals

    International Nuclear Information System (INIS)

    Vysotskij, V.I.; Vorontsov, V.I.; Kuz'min, R.N.

    1987-01-01

    Physical predictions and quantitative estimations of a new physical effect - the phenomenon of quantum bremsstrahlung induced selfmodulation of a fast beam channeling in the crystals are considered and carried out. The occurrence of induced self-modulation results from nonstationary interference of proper waves of a channeled particle in the range of mutual coherence and with account of difference of selective bremsstrahlung losses of these waves. The modulation frequency for superrelativistic particles is shown to lie within the range from soft X-ray to hard gamma range. It proceeds from the estimations that modulation at these frequencies is preserved within the limits of macroscopically large ranges after the crystal attaining several meters. The maximum frequency of modulation for nonrelativistic heavy particles (protons) corresponds to the optical range

  5. Development of a radioiodinated triazolopyrimidine probe for nuclear medical imaging of fatty acid binding protein 4.

    Directory of Open Access Journals (Sweden)

    Kantaro Nishigori

    Full Text Available Fatty acid binding protein 4 (FABP4 is the most well-characterized FABP isoform. FABP4 regulates inflammatory pathways in adipocytes and macrophages and is involved in both inflammatory diseases and tumor formation. FABP4 expression was recently reported for glioblastoma, where it may participate in disease malignancy. While FABP4 is a potential molecular imaging target, with the exception of a tritium labeled probe there are no reports of other nuclear imaging probes that target this protein. Here we designed and synthesized a nuclear imaging probe, [123I]TAP1, and evaluated its potential as a FABP4 targeting probe in in vitro and in vivo assays. We focused on the unique structure of a triazolopyrimidine scaffold that lacks a carboxylic acid to design the TAP1 probe that can undergo facilitated delivery across cell membranes. The affinity of synthesized TAP1 was measured using FABP4 and 8-anilino-1-naphthalene sulfonic acid. [125I]TAP1 was synthesized by iododestannylation of a precursor, followed by affinity and selectivity measurements using immobilized FABPs. Biodistributions in normal and C6 glioblastoma-bearing mice were evaluated, and excised tumors were subjected to autoradiography and immunohistochemistry. TAP1 and [125I]TAP1 showed high affinity for FABP4 (Ki = 44.5±9.8 nM, Kd = 69.1±12.3 nM. The FABP4 binding affinity of [125I]TAP1 was 11.5- and 35.5-fold higher than for FABP3 and FABP5, respectively. In an in vivo study [125I]TAP1 displayed high stability against deiodination and degradation, and moderate radioactivity accumulation in C6 tumors (1.37±0.24% dose/g 3 hr after injection. The radioactivity distribution profile in tumors partially corresponded to the FABP4 positive area and was also affected by perfusion. The results indicate that [125I]TAP1 could detect FABP4 in vitro and partly in vivo. As such, [125I]TAP1 is a promising lead compound for further refinement for use in in vivo FABP4 imaging.

  6. Simulations of bremsstrahlung emission in ultra-intense laser interactions with foil targets

    Science.gov (United States)

    Vyskočil, Jiří; Klimo, Ondřej; Weber, Stefan

    2018-05-01

    Bremsstrahlung emission from interactions of short ultra-intense laser pulses with solid foils is studied using particle-in-cell (PIC) simulations. A module for simulating bremsstrahlung has been implemented in the PIC loop to self-consistently account for the dynamics of the laser–plasma interaction, plasma expansion, and the emission of gamma ray photons. This module made it possible to study emission from thin targets, where refluxing of hot electrons plays an important role. It is shown that the angular distribution of the emitted photons exhibits a four-directional structure with the angle of emission decreasing with the increase of the width of the target. Additionally, a collimated forward flash consisting of high energy photons has been identified in thin targets. The conversion efficiency of the energy of the laser pulse to the energy of the gamma rays rises with both the driving pulse intensity, and the thickness of the target. The amount of gamma rays also increases with the atomic number of the target material, despite a lower absorption of the driving laser pulse. The angular spectrum of the emitted gamma rays is directly related to the increase of hot electron divergence during their refluxing and its measurement can be used in experiments to study this process.

  7. Study of bremsstrahlung dose fields in radiation shield and labyrinth devices of plants with LUEH-8/5B accelerator

    International Nuclear Information System (INIS)

    Vikulin, A.A.; Vanyushkin, B.M.; Garnyk, D.V.; Kon'kov, N.G.; Terent'ev, B.M.

    1980-01-01

    Measurement results of exposure dose rate (EDR) of radiation in fields of bremsstrahlung of radiation plants with LUEh-8/5B linear accelerator of electrons by means of DRG2-03 dose meter, intended for operative measuring EDR in high intense fields of γ-radiation of powerful radioisotopic plants, are presented. Dose meter design is described. Measurements of bremsstrahlung EDR have been carried out in the chamber of plant irradiation for radiation sterilizing medical items, as well as in the chamber of VNIIRT experimental plant. RUP-1 device has been used for measuring radiation EDR in a labyrinth behind 1.8 m thick shoulder by concrete [ru

  8. Model for bremsstrahlung emission accompanying interactions between protons and nuclei from low energies up to intermediate energies: Role of magnetic emission

    Science.gov (United States)

    Maydanyuk, Sergei P.

    2012-07-01

    A model of the bremsstrahlung emission which accompanies proton decay and collisions of protons off nuclei in the low- to intermediate-energy region has been developed. This model includes spin formalism, a potential approach for describing the interaction between protons and nuclei, and an emission that includes a component of the magnetic emission (defined on the basis of the Pauli equation). For the problem of bremsstrahlung during proton decay the role of magnetic emission is studied by using such a model. For the 146Tm nucleus the following has been studied: (1) How much does the magnetic emission change the full bremsstrahlung spectrum? (2) At which angle is the magnetic emission the most intensive relative to the electric emission? (3) Is there some spatial region where the magnetic emission increases strongly relative to the electric emission? (4) How intensive is the magnetic emission in the tunneling region? (5) Which is the maximal probability? Which value does it equal to at the zero-energy limit of the emitted photons? It is demonstrated that the model is able to describe well enough experimental data of bremsstrahlung emission which accompanies collisions of protons off 9C, 64Cu, and 107Ag nuclei at an incident energy of Tlab=72 MeV (at a photon energy up to 60 MeV) and off 9Be, 12C, and 208Pb nuclei at an incident energy of Tlab=140 MeV (at a photon energy up to 120 MeV).

  9. NN wave function at small distances and hard bremsstrahlung in the process pp→ppγ

    International Nuclear Information System (INIS)

    Neudatchin, V. G.; Khokhlov, N. A.; Shirokov, A. M.; Knyr, V. A.

    1997-01-01

    Various possibilities of studying the NN wave function at small distances--and in particular, quark degrees of freedom in the NN system--are discussed. It is shown that there is such a possibility at moderate energies--namely, hard bremsstrahlung in the process pp→ppγ at proton-beam energies in the range 350-450 MeV permits distinguishing between the pp wave function with nodes in S and P waves that corresponds to the Moscow potential of NN interaction from functions obtained with repulsive-core mesonic potentials. In the regions where photon energies in the c.m.s. are maximal (forward and backward photon emission angles in the laboratory frame), the pp→ppγ cross section calculated with the Moscow potential has maxima at which it is approximately five times larger than the analogous cross section calculated with repulsive-core mesonic potentials. The coordinate-representation formalism of the theory of bremsstrahlung is expounded

  10. Nuclear micro-probe analysis of Arabidopsis thaliana leaves

    International Nuclear Information System (INIS)

    Ager, F.J.; Ynsa, M.D.; Dominguez-Solis, J.R.; Lopez-Martin, M.C.; Gotor, C.; Romero, L.C.

    2003-01-01

    Phytoremediation is a cost-effective plant-based approach for remediation of soils and waters which takes advantage of the remarkable ability of some plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues, such as toxic heavy metals and organic pollutants. Nowadays, phytoremediation technology is becoming of paramount importance when environmental decontamination is concerned, due to the emerging knowledge of its physiological and molecular mechanisms and the new biological and engineering strategies designed to optimize and improve it. In addition, the feasibility of using plants for environmental cleanup has been confirmed by many different trials around the world. Arabidopsis thaliana plants can be used for basic studies to improve the technology on phytoremediation. Making use of nuclear microscopy techniques, in this paper we study leaves of wild type and transgenic A. thaliana plants grown in a cadmium-rich environment under different conditions. Micro-PIXE, RBS and SEM analyses, performed on the scanning proton micro-probe at the CNA in Seville (Spain), prove that cadmium is preferentially sequestered in the central region of epidermal trichome and allow comparing the effects of genetic modifications

  11. Characterization of Radiation-Induced Clustering using Atom Probe Tomography in Nuclear Structural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gyeong Geun; Lim, Sang Yeob; Chang, Kun Ok; Ha, Jin Hyung; Kwon, Jun Hyun [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The degradations include the change in mechanical properties, which are related to the microstructure evolution caused by irradiation. The most widely used tool for the imaging irradiated microstructure is transmission electron microscopy (TEM). The composition of irradiation defects can be analyzed using X-ray spectroscopy (EDS) equipped in the TEM. However, composition characterization of the nano-sized irradiation defects in the matrix is limited due to the beam broadening of TEM and the overlapping of the probed volume during EDS analysis. Recently, Atom probe tomography (APT) has been introduced to the characterization of irradiation defects. APT provides sub-nano scale position of atoms and the chemical composition of a selected volume. SS316 irradiated with Fe ions at above 300 .deg. C caused significant clustering and segregation of Si and Ni at defect sinks. The neutron irradiated low alloy steel showed similar clustering of Ni and Si. The approach of using APT was demonstrated to be well suited for discovering the structure of irradiation defects and performing quantitative analysis in nuclear materials irradiated at high temperature.

  12. Probe specificity

    International Nuclear Information System (INIS)

    Laget, J.M.

    1986-11-01

    Specificity and complementarity of hadron and electron probes must be systematically developed to answer three questions currently asked in intermediate energy nuclear physics: what is nucleus structure at short distances, what is nature of short range correlations, what is three body force nature [fr

  13. Probes for inspections of heat exchanges installed at nuclear power plants type PWR by eddy current method

    International Nuclear Information System (INIS)

    Silva, Alonso F.O.

    2007-01-01

    From all non destructive examination methods usable to perform integrity evaluation of critical equipment installed at nuclear power plants (NPP), eddy current test (ET) may be considered the most important one, when examining heat exchangers. For its application, special probes and reference calibration standards are employed. In pressurized water reactor (PWR) NPPs, a particularly critical equipment is the steam generator (SG), a huge heat exchanger that contains thousands of U-bend thin wall tubes. Due to its severe working conditions (pressure and temperature), that component is periodically examined by means of ET. In this paper a revision of the operating fundamentals of the main ET probes, used to perform SG inspections is presented. (author)

  14. Measurement of the linear polarization of the photons in the elementary processes of bremsstrahlung production

    International Nuclear Information System (INIS)

    Bleier, W.

    1983-01-01

    The polarization of the photons in the elementary processes of the electron-nucleus and electron-electron bremsstrahlung was measured. Electrons with an energy of 300 keV were scattered by copper, gold and carbon target. The polarization in the different processes was measured by using different coincidence methods. (BEF)

  15. Effects of a neutral current on the neutrino bremsstrahlung

    International Nuclear Information System (INIS)

    Ju, I.

    1977-01-01

    The energy-loss rate due to the neutrino bremsstrahlung from relativistic electrons in a dense matter such as a star is calculated in the framework of Weinberg's unified theory of weak and electromagnetic interactions by using the method of neutrino-energy expansion. The momentum-transfer integration, though complicated, can be carried out analytically, but the subsequent two electron integrals, called the distribution integrals, are helpless and do not allow any further analytic calculation. In order to avoid this difficulty, we set up a set of variables whose integration is simple enough to be expanded in series. It turns out that this series becomes a power series in the Fermi energy inverse after the distribution integrals. This enables us to keep only the leading terms, greatly simplifying the final result. Thus in principle we will be able to calculate arbitrary higher-order terms, even though most of them require prohibitively tedious labor. We carry out the next-higher-order calculations to find that the correction to the lowest-order contribution is within 5%. This confirms the earlier calculations of Festa and Ruderman, even though the two approaches are quite different: the neutrino-bremsstrahlung energy-loss rate is proportional to T 6 and independent of the density at extremely relativistic degenerate regions. We find that the asymptotic expression for the energy-loss rate is of the form A (β) + (rho/μ/sub e/) -1 / 3 kTB (β). The most striking effect of the neutral current is the muon-neutrino emission. The ratio of the energy-loss rate in Weinberg's theory to that in the conventional theory is 1/2 + 4 sin 4 theta/sub W/ at the extreme relativistic-degenerate and nondegenerate-nonrelativistic regions

  16. Semi-empirical model to determine pure β--emitters in closed waste packages using Bremsstrahlung radiation

    International Nuclear Information System (INIS)

    Takacs, S.; Hermanne, A.

    2001-01-01

    Medical establishments and research laboratories use many different type of radionuclides for diagnostic, therapeutic and research purposes. As a final by product large amount of medical waste are produced. This waste represents both biological and radiation hazards, therefore it requires special treatments in both point of view. Biomedical waste is usually best managed on site by decay storage, with minimal transport risk and ALARA (as low as reasonably achieved) exposure levels. The nuclear medical waste has characteristics fundamentally different from the nuclear fuel cycle waste. In medical practice radioactive material is used both in sealed and unsealed form, but major part of the medical waste is produced by using unsealed isotopes of relatively short half-life in most cases less than 100 days and of low specific activity. There are gamma-emitter, position-emitter and pure beta-knitter among these isotopes. The positron-emitter isotopes have usually less than 2 hours half-life; therefore they do not contribute too much to the volume of the radioactive waste since they decay rapidly. Among the γ- and pure β - - emitters there are isotopes with half-life from seconds to several hundred days. Waste containing isotopes with longer half-life contributes mainly to that large volume of waste produced regularly at biomedical sites. On site decay storage requires accurate determination of activity levels. Since quantitative estimation of isotope activity can be difficult where waste packages contain a mixed combination of β - -γ-emitters, segregation at the time of waste production is essential. Accurate identification and quantitative measurement of γ-emitter isotopes is possible with a large volume, reverse electrode, high purity germanium detector even those cases when the isotope emits only low energy gamma photons. However, there is problem with the pure β - emitting isotopes to measure. In biological health care and pharmaceutical research a range of

  17. Nonlinear Breit–Wheeler pair creation with bremsstrahlung γ rays

    Science.gov (United States)

    Blackburn, T. G.; Marklund, M.

    2018-05-01

    Electron–positron pairs are produced through the Breit–Wheeler process when energetic photons traverse electromagnetic fields of sufficient strength. Here we consider a possible experimental geometry for observation of pair creation in the highly nonlinear regime, in which bremsstrahlung of an ultrarelativistic electron beam in a high-Z target is used to produce γ rays that collide with a counter-propagating laser pulse. We show how the target thickness may be chosen to optimize the yield of Breit–Wheeler positrons, and verify our analytical predictions with simulations of the cascade in the material and in the laser pulse. The electron beam energy and laser intensity required are well within the capability of today’s high-intensity laser facilities.

  18. Laser radiography forming bremsstrahlung radiation to image an object

    Science.gov (United States)

    Perry, Michael D.; Sefcik, Joseph A.

    2004-01-13

    A method of imaging an object by generating laser pulses with a short-pulse, high-power laser. When the laser pulse strikes a conductive target, bremsstrahlung radiation is generated such that hard ballistic high-energy electrons are formed to penetrate an object. A detector on the opposite side of the object detects these electrons. Since laser pulses are used to form the hard x-rays, multiple pulses can be used to image an object in motion, such as an exploding or compressing object, by using time gated detectors. Furthermore, the laser pulses can be directed down different tubes using mirrors and filters so that each laser pulse will image a different portion of the object.

  19. Accuracy improvement of the laplace transformation method for determination of the bremsstrahlung spectra in clinical accelerators

    International Nuclear Information System (INIS)

    Scheithauer, M.; Schwedas, M.; Wiezorek, T.; Wendt, T.

    2003-01-01

    The present study focused on the reconstruction of the bremsstrahlung spectrum of a clinical linear accelerator from the measured transmission curve, with the aim of improving the accuracy of this method. The essence of the method was the analytic inverse Laplace transform of a parameter function fitted to the measured transmission curve. We tested known fitting functions, however they resulted in considerable fitting inaccuracy, leading to inaccuracies of the bremsstrahlung spectrum. In order to minimise the fitting errors, we employed a linear combination of n equations with 2n-1 parameters. The fitting errors are now considerably smaller. The measurement of the transmission function requires that the energy-dependent detector response is taken into account. We analysed the underlying physical context and developed a function that corrects for the energy-dependent detector response. The factors of this function were experimentally determined or calculated from tabulated values. (orig.) [de

  20. SU-E-E-08: Applications of the Quantization of Coupled Circuits in Radiation Physics (design of Klystron, Bremsstrahlung, Synchrotron)

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, W

    2015-06-15

    Purpose: During the past decade the quantization of coupled/forced electromagnetic circuits with or without Ohm’s resistance has gained the subject of some fundamental studies, since even problems of quantum electrodynamics can be solved in an elegant manner, e.g. the creation of quantized electromagnetic fields. In this communication, we shall use these principles to describe optimization procedures in the design of klystrons, synchrotron irradiation and high energy bremsstrahlung. Methods: The base is the Hamiltonian of an electromagnetic circuit and the extension to coupled circuits, which allow the study of symmetries and perturbed symmetries in a very apparent way (SU2, SU3, SU4). The introduction resistance and forced oscillators for the emission and absorption in such coupled systems provides characteristic resonance conditions, and atomic orbitals can be described by that. The extension to virtual orbitals leads to creation of bremsstrahlung, if the incident electron (velocity v nearly c) is described by a current, which is associated with its inductivitance and the virtual orbital to the charge distribution (capacitance). Coupled systems with forced oscillators can be used to amplify drastically the resonance frequencies to describe klystrons and synchrotron radiation. Results: The cross-section formula for bremsstrahlung given by the propagator method of Feynman can readily be derived. The design of klystrons and synchrotrons inclusive the radiation outcome can be described and optimized by the determination of the mutual magnetic couplings between the oscillators induced by the currents. Conclusions: The presented methods of quantization of circuits inclusive resistance provide rather a straightforward way to understand complex technical processes such as creation of bremsstrahlung or creation of radiation by klystrons and synchrotrons. They can either be used for optimization procedures and, last but not least, for pedagogical purposes with regard to

  1. Bremsstrahlung emission coefficient of a plasma in a uniform magnetic field

    International Nuclear Information System (INIS)

    Pangborn, R.J.

    1976-01-01

    The leading (electron-ion, dipole) contribution to the bremsstrahlung spectrum of a Maxwellian plasma in a constant, uniform magnetic field is calculated. The plasma is assumed infinite and fully ionized. A simpler, more direct derivation of Kirchoff's Law for anisotropic media is presented. The plasma dispersion relation is then found using previously obtained expressions for the conductivity tensor (accurate to first order in collisional effects). From the dispersion the collisional damping, assumed small, is obtained and by means of Kirchoff's Law an expression for the bremsstrahlung emission coefficient is written. No terms of order (kappa 2 lambda 2 0 ) or higher are included. For wave frequencies large compared with the plasma and electron cyclotron frequencies (ω 2 much greater than ω 2 rho, ω 2 much greater than Ω 3 ) an expansion of the exact result is given accurate to fourth order in Ω/ω and ω rho/ω. The result is found to disagree with previous high frequency expressions. Analysis of the exact expression reveals that for certain frequencies and directions of propagation the emission spectrum exhibits a resonance quality. The results are presented in such fashion that for various magnetic field strengths the frequency of the resonant emission at arbitrary angle relative to the field is easily obtained. These phenomena arise due to the influence of the magnetic fieldon the dielectric properties of the plasma and not because of its effect on the binary collision process. A physical explanation of the results is presented

  2. Instrumental neutron activation analysis of phosphorus in biological materials by Bremsstrahlung measurement

    International Nuclear Information System (INIS)

    Bajo, S.; Wyttenbach, A.

    1986-12-01

    The determination of phosphorus in biological materials by instrumental neutron activation via the reaction 31 P (n,γ) 32 P is described. The Bremsstrahlung produced by 32 P is measured in a well-type NaI(Tl) detector. The samples are measured within the polyethylene irradiation container with no changes between irradiation and measurement. The sources of error were studied and the proposed method was applied to the determination of phosphorus in ten internationally certified materials. (author)

  3. Spectral tomographic analysis of Bremsstrahlung X-rays generated in a laser-produced plasma

    Czech Academy of Sciences Publication Activity Database

    Rhee, Y.-J.; Nam, S. M.; Peebles, W.; Sawada, H.; Wei, M.; Vaisseau, X.; Sasaki, T.; Giuffrida, Lorenzo; Hulin, S.; Vauzour, B.; Santos, J.J.; Batani, D.; McLean, H. S.; Patel, P. K.; Li, Y.; Yuan, D. W.; Zhang, K.; Zhong, J. Y.; Fu, C. B.; Hua, N.; Li, K.; Zhang, Y.; Zhu, J. Q.; Kim, I. J.; Jeon, J. H.; Jeong, T.M.; Choi, I.W.; Lee, H. W.; Sung, J.H.; Lee, S.K.; Nam, C.H.

    2016-01-01

    Roč. 34, č. 4 (2016), s. 645-654 ISSN 0263-0346 R&D Projects: GA MŠk LQ1606; GA MŠk EF15_008/0000162 Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 Keywords : Bremsstrahlung X-ray * filter stack spectrometer * laser-produced plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.420, year: 2016

  4. Photoactivation of the p-nucleus 92Mo at the bremsstrahlung measurement place of ELBE

    International Nuclear Information System (INIS)

    Erhard, Martin Andreas

    2010-01-01

    By the high intensity of the bremsstrahlung of up to 20 MeV to 10 9 MeV -1 cm -2 s -1 in the energy range up to 20 MeV in the framework of this thesis for the first time not only the (γ,n), but also the (γ,p) reactions could be studied on 92 Mo at astrophysically relevant energies.

  5. Comprehensive clinical validation of the nuclear stethoscope

    Energy Technology Data Exchange (ETDEWEB)

    Caruana, M.; Jones, R.; Lahiri, A.; Brigden, G.; Rodrigues, E.; Dore, C.; Raftery, E.B.

    1986-10-01

    Five studies were conducted to examine the degree of variability to be expected during the use of the non-imaging nuclear probe (BIOS Inc.) under a variety of clinical conditions. Comparison of the ejection fraction (EF) readings between the nuclear probe and a gamma camera showed good agreement, with the nuclear probe tending to underestimate lower, and overestimate higher camera EF values. It is concluded that the portable, low cost nuclear probe produces accurate EF measurements when compared with the gamma camera.

  6. The nucleon-nucleon interaction in the presence of the electromagnetic field: Nucleon-nucleon bremsstrahlung

    International Nuclear Information System (INIS)

    Brown, V.R.

    1990-01-01

    Nucleon-nucleon bremsstrahlung, NNγ, is a fundamental process, which involves the strong and electromagnetic fields acting simultaneously. Since the electromagnetic interaction is well known, NNγ provides a calculable tool for comparing off-energy-shell effects from different two-nucleon potentials compared to experiment and also provides a simple testing ground, which is sensitive to meson-exchange-current contributions that are so important in electronuclear physics. Historically, experimental studies have focused on ppγ, with only a few measurements of npγ. The present workshop was organized primarily to investigate the interest in, the value of, and the feasibility of doing an npγ experiment using the neutron white source at LANL. An increasing amount of US nuclear physics dollars are being spent on electronuclear physics. npγ is a fundamental process with large meson-exchange currents. In the npγ calculations of Brown and Franklin, the meson-exchange contributions increase the cross section by a factor of roughly two and later the angular distribution of the emitted photon dramatically. The details of these calculated effects have never been verified experimentally, but the proper quantum-mechanical inclusion of meson-exchange contributions, using the methods of brown and Franklin, has proved to be essential in understanding the heavy-ion results. The understanding of the importance of such terms is extremely important inelectronuclear processes, such as are presently under investigation or being planned at Bates, SLAC, and CEBAF. Just one example is in the electrodisintegration of the deuteron, where meson-exchange contributions must be included properly before any conclusions about nuclear models, such as QCD versus meson-exchange potentials can be made

  7. Relativistic electron acceleration by net inverse bremsstrahlung in a laser-irradiated plasma

    International Nuclear Information System (INIS)

    Kim, S.H.; Chen, K.W.

    1985-01-01

    Using the quantum-kinetic method, the net acceleration of relativistic electrons in a laser-irradiated plasma is studied as a function of the relevant parameters of the incident laser wave and the plasma wave. It is suggested that, in general, the net acceleration in laser-produced turbulent plasmas is primarily due to inverse bremsstrahlung proceses, and the acceleration gradient exceeds several hundreds gigavolt per meter when the electron energy is large (TeV) and the momentum spread of the beam is properly controlled

  8. Decay energy of 55Fe from its inner Bremsstrahlung spectrum

    Science.gov (United States)

    Keshava, S. L.; Gopala, K.; Venkataramaiah, P.

    2001-06-01

    Several measurements of decay energy using the inner Bremsstrahlung spectrum (IB) due to radiative electron capture in 55Fe has been made. But the results are not uniform. Hence another attempt has been made at the same. Experimental data was obtained with a 4.445 cm. dia ' 5.08 cm thick NaI (Tl) detector. It was subjected to suitable statistical treatment and various corrections using Liden and Starfelt procedure. The corrected spectrum agrees well with the Glauber and Martin theory for 1s electron capture beyond 100 keV. From the Jauch plot, the decay energy of 232.36 +/-0.64 keV was obtained.

  9. Decay energy of 55Fe from its inner Bremsstrahlung spectrum

    International Nuclear Information System (INIS)

    Keshava, S.L.; Gopala, K.; Venkataramaiah, P.

    2001-01-01

    Several measurements of decay energy using the inner Bremsstrahlung spectrum (IB) due to radiative electron capture in 55 Fe has been made. But the results are not uniform. Hence another attempt has been made at the same. Experimental data was obtained with a 4.445 cm dia x 5.08 cm thick NaI (Tl) detector. It was subjected to suitable statistical treatment and various corrections using Liden and Starfelt procedure. The corrected spectrum agrees well with the Glauber and Martin theory for l s electron capture beyond 100 keV. From the Jauch plot, the decay energy of 232.36±0.64 keV was obtained. (author)

  10. The LPM effect in sequential bremsstrahlung: dimensional regularization

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Peter; Chang, Han-Chih [Department of Physics, University of Virginia,382 McCormick Road, Charlottesville, VA 22894-4714 (United States); Iqbal, Shahin [National Centre for Physics,Quaid-i-Azam University Campus, Islamabad, 45320 (Pakistan)

    2016-10-19

    The splitting processes of bremsstrahlung and pair production in a medium are coherent over large distances in the very high energy limit, which leads to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. Of recent interest is the case when the coherence lengths of two consecutive splitting processes overlap (which is important for understanding corrections to standard treatments of the LPM effect in QCD). In previous papers, we have developed methods for computing such corrections without making soft-gluon approximations. However, our methods require consistent treatment of canceling ultraviolet (UV) divergences associated with coincident emission times, even for processes with tree-level amplitudes. In this paper, we show how to use dimensional regularization to properly handle the UV contributions. We also present a simple diagnostic test that any consistent UV regularization method for this problem needs to pass.

  11. A high resolution beam profile monitor using Bremsstrahlung

    International Nuclear Information System (INIS)

    Norem, J.

    1988-01-01

    The development of efficient high energy linear colliders in the 1 TeV range requires final focus systems capable of producing beam spot sizes on the order of 1--20 nm, about three orders of magnitude smaller than those produced at the SLC. Although beam line designs exist which can, in principle, produce the required optics, the construction of quadrupoles with the size and precision required will be challenging. Field errors in these quads must be small and should be verified experimentally, which is difficult with existing technology. This paper describes a proposal to use bremsstrahlung from heavy targets to measure high energy beam profiles and positions with a resolution approaching a few nm. The method is also applicable to tests of other final focus systems (flat beams, plasma lenses) at lower energies. 6 refs., 3 figs., 1 tab

  12. Internal Bremsstrahlung accompanying beta decay of 90 Y

    International Nuclear Information System (INIS)

    Elsayed, A.M.A.; Abdelhady, E.E.

    1992-01-01

    The internal Bremsstrahlung (IB) spectrum associated with the unique first-forbidden β decay of 9 0Y is measured employing the conventional β-stopper technique with a 5 x 5 cm NaI (T 1) scintillation spectrometer in the energy range (50-2000 keV). All the necessary corrections are made. In order to analyze the experimental data, a response matrix having the dimensions of 64 energy bins and 474 channels is constructed.with the help of the detector assembly response matrix, the true IB energy spectrum is obtained by iteratively unfolding the experimental pulse-height spectrum. The experimental results are compared with the corresponding theoretical distributions due to Knipp and Uhlenbeck and Bloch (KUB), lewis and ford (L F), and ford and martin (FM). The results show reasonable agreement with the detour theory of ford and martin.3 fig

  13. Quantum erasers and probing classifications of entanglement via nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Teklemariam, G.; Fortunato, E.M.; Pravia, M.A.; Sharf, Y.; Havel, T.F.; Cory, D.G.; Bhattaharyya, A.; Hou, J.

    2002-01-01

    We report the implementation of two- and three-spin quantum erasers using nuclear magnetic resonance (NMR). Quantum erasers provide a means of manipulating quantum entanglement, an important resource for quantum information processing. Here, we first use a two-spin system to illustrate the essential features of quantum erasers. The extension to a three-spin 'disentanglement eraser' shows that entanglement in a subensemble can be recovered if a proper measurement of the ancillary system is carried out. Finally, we use the same pair of orthogonal decoherent operations used in quantum erasers to probe the two classes of entanglement in tripartite quantum systems: the Greenberger-Horne-Zeilinger state and the W state. A detailed presentation is given of the experimental decoherent control methods that emulate the loss of phase information in strong measurements, and the use of NMR decoupling techniques to implement partial trace operations

  14. Practice for dosimetry in an X-ray (bremsstrahlung) facility for radiation processing. 2. ed.

    International Nuclear Information System (INIS)

    2002-01-01

    This practice covers dosimetric procedures to be followed in facility characterization, process qualification, and routine processing using X rays (bremsstrahlung) to ensure that the entire product has been treated within an acceptable range of absorbed doses. Other procedures related to facility characterization, process qualification, and routine processing that may influence absorbed dose in the product are also discussed. The establishment of effective or regulatory dose and X-ray energy limits are not within the scope of this practice. In contrast to monoenergetic gamma rays, the bremsstrahlung energy spectrum extends from low values up to the maximum energy of the electrons incident on the X-ray target (see Section 5 and Annex A1). Dosimetry is only one component of a total quality assurance program for an irradiation facility. Other controls besides dosimetry may be required for specific applications such as medical device sterilization and food preservation. For the irradiation of food and the radiation sterilization of health care products, other specific ISO standards exist. For food irradiation, see ISO/ASTM Practice 51431. For the radiation sterilization of health care products, see ISO 11137:1995. In those areas covered by ISO 11137, that standard takes precedence

  15. One-loop corrections to the process e+e-→tt including hard bremsstrahlung

    International Nuclear Information System (INIS)

    Fleischer, J.; Riemann, T.; Werthenbach, A.; Leike, A.

    2002-03-01

    Radiative corrections to the process e + e - → t anti t are calculated in one-loop approximation of the Standard Model. There exist results from several groups. This talk provides further comparisons of the complete electroweak contributions, including hard bremsstrahlung. The excellent final agreement of the different groups allows to continue by working on a code for an event generator for TESLA and an extension to e + e - → 6 fermions. (orig.)

  16. Gravitational bremsstrahlung in ultra-planckian collisions

    CERN Document Server

    Gal'tsov, Dmitry; Tomaras, Theodore N

    2013-01-01

    A classical computation of gravitational bremsstrahlung in ultra-planckian collisions of massive point particles is presented in an arbitrary number d of toroidal or non-compact extra dimensions. Our method generalizes the post-linear formalism of General Relativity to the multidimensional case. The total emitted energy, as well as its angular and frequency distribution are discussed in detail. In terms of the gravitational radius r_S of the collision energy, the impact parameter b and the Lorentz factor in the CM frame, the leading order radiation efficiency in the Lab frame is shown to be of order (r_S/b)^{3(d+1)} gamma_{cm} for d=0, 1 and of order (r_S/b)^{3(d+1)} gamma_{cm}^{2d-3} for d>1, up to a known d-dependent coefficient and a ln gamma_{cm} factor for d=2, while the characteristic frequency of the radiation is gamma/b. The contribution of the low frequency part of the radiation (soft gravitons) to the total radiated energy is shown to be negligible for all values of d. The domain of validity of the ...

  17. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    Energy Technology Data Exchange (ETDEWEB)

    Morris, C. L.; Bourke, M.; Byler, D. D.; Chen, C. F.; Hogan, G.; Hunter, J. F.; Kwiatkowski, K.; Mariam, F. G.; McClellan, K. J.; Merrill, F.; Morley, D. J.; Saunders, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2013-02-15

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. We also show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods have been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 {mu}m has been demonstrate, 20 {mu}m seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 {mu}m resolution but further development of sources, collimation, and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.

  18. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    International Nuclear Information System (INIS)

    Morris, C. L.; Bourke, M.; Byler, D. D.; Chen, C. F.; Hogan, G.; Hunter, J. F.; Kwiatkowski, K.; Mariam, F. G.; McClellan, K. J.; Merrill, F.; Morley, D. J.; Saunders, A.

    2013-01-01

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. We also show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods have been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation, and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.

  19. Triton-3He relative and differential flows as probes of the nuclear symmetry energy at supra-saturation densities

    International Nuclear Information System (INIS)

    Yong Gaochan; Li Baoan; Chen Liewen; Zhang Xunchao

    2009-01-01

    Using a transport model coupled with a phase-space coalescence afterburner, we study the triton- 3 He (t- 3 He) ratio with both relative and differential transverse flows in semicentral 132 Sn+ 124 Sn reactions at a beam energy of 400 MeV/nucleon. The neutron-proton ratios with relative and differential flows are also discussed as a reference. We find that similar to the neutron-proton pairs, the t- 3 He pairs also carry interesting information regarding the density dependence of the nuclear symmetry energy. Moreover, the nuclear symmetry energy affects more strongly the t- 3 He relative and differential flows than the π - /π + ratio in the same reaction. The t- 3 He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.

  20. Measurement of activity yields for 12C(#betta#, n)11C, 14N(#betta#, n)13N, and 16O(#betta#, n)15O reactions as a function of electron beam energy and angle from the electron beam using thick target produced bremsstrahlung

    International Nuclear Information System (INIS)

    Piltingsrud, H.V.

    1983-01-01

    The calculation of activity yields from practical photonuclear target systems designed to produce short-lived positron emitting radionuclides for nuclear medicine purposes requires certain basic information. These include a knowledge of the photon source (bremsstrahlung energy spectrum and intensity as a function of angle from the electron beam) and the #betta#, n activation cross section of the secondary target element. A lack of adequate information concerning these parameters motivated the present study in which activity yields for the reactions 12 C(#betta#, n) 11 C, 14 N(#betta#, n) 13 N, and 16 O(#betta#, n) 15 O were measured as a function of energy of and angle from the electron beam between 16 and 30 MeV and 0 0 and 30.5 0 , respectively. The data indicate highly complex relationships between the activity yield and the experimental variables. Also indicated are possible applications of the data to indicate the energy of an electron beam producing a given bremsstrahlung field in which activation measurements are made

  1. Yields of Radionuclides Created by Photonuclear Reactions on Be, C, Na, Cl, and Ge, Using Bremsstrahlung of 150-MeV Electrons

    International Nuclear Information System (INIS)

    Dickens, J.K.

    2001-01-01

    The bremsstrahlung created by 150-MeV electrons impinging on a tantalum radiator was used to study photonuclear reactions on samples containing Be, C, Na, Cl and Ge. For Ge fifteen radioisotopes, ranging in half life between 2.6 min and 271 days, and in mass between 65 and 75, were obtained in sufficient amount to determine their yields quantitatively using known decay gamma-rays. Special equipment is described which was developed to create the bremsstrahlung using a beam-sharing mode, while minimizing the neutron flux on the sample. Relative production rates were determined. These were analyzed to provide absolute average cross sections for production of three reactions

  2. Accuracy evaluation of a Compton X-ray spectrometer with bremsstrahlung X-rays generated by a 6 MeV electron bunch

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, Sadaoki, E-mail: kojima-s@ile.osaka-u.ac.jp; Arikawa, Yasunobu; Zhang, Zhe; Ikenouchi, Takahito; Morace, Alessio; Nagai, Takahiro; Abe, Yuki; Sakata, Shouhei; Inoue, Hiroaki; Utsugi, Masaru; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Fujioka, Shinsuke; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nishimura, Yasuhiko; Togawa, Hiromi [Toyota Technical Development Corporation, 1-21 Imae, Hanamoto-cho, Toyota, Aichi 470-0334 (Japan); Ozaki, Tetsuo [National Institute for Fusion Science, 322-6 Oroshicho, Toki, Gifu 509-5292 (Japan); Kato, Ryukou [The Institute of Science and Industrial Research, Osaka University, 2-6 Yamada-oka, Suita, Osaka (Japan)

    2014-11-15

    A Compton-scattering-based X-ray spectrometer is developed to obtain the energy distribution of fast electrons produced by intense laser and matter interactions. Bremsstrahlung X-rays generated by fast electrons in a material are used to measure fast electrons’ energy distribution in matter. In the Compton X-ray spectrometer, X-rays are converted into recoil electrons by Compton scattering in a converter made from fused silica glass, and a magnet-based electron energy analyzer is used to measure the energy distribution of the electrons that recoil in the direction of the incident X-rays. The spectrum of the incident X-rays is reconstructed from the energy distribution of the recoil electrons. The accuracy of this spectrometer is evaluated using a quasi-monoenergetic 6 MeV electron bunch that emanates from a linear accelerator. An electron bunch is injected into a 1.5 mm thick tungsten plate to produce bremsstrahlung X-rays. The spectrum of these bremsstrahlung X-rays is obtained in the range from 1 to 9 MeV. The energy of the electrons in the bunch is estimated using a Monte Carlo simulation of particle-matter interactions. The result shows that the spectrometer's energy accuracy is ±0.5 MeV for 6.0 MeV electrons.

  3. An investigation into the possibilities and utility of an IKO gamma-ray facility, pt. 1

    International Nuclear Information System (INIS)

    Hicks, R.

    1976-01-01

    Experiments on nuclei using purely electromagnetic probes are transparent in that the interaction is among the simplest and best understood in nuclear physics. This report is directed to the possible capabilities and applications of an IKO photon facility. Particular emphasis is given to the bremsstrahlung monochromator. This is a device for identifying or tagging the energies of individual photons in a γ-ray beam that is continuous in energy. In this study the various experimental techniques for producing beams of photons are discussed

  4. Hard photon interferometry in heavy-ion collisions

    International Nuclear Information System (INIS)

    Schutz, Y.

    1993-01-01

    It is shown how first- and second-order interference effects can be used to measure the extent of chaotic light sources such as stars viewed from a great distance. The same technique can be applied in nuclear physics where the interference effect arises from the quantum statistics of identical particles. The results from an experiment attempting to measure the size of the participant zone in a heavy-ion reaction using bremsstrahlung photons as a probe are presented. (author) 16 refs., 7 figs

  5. Nuclear structure theory. Annual technical progress report, 1 July 1974--30 June 1975

    International Nuclear Information System (INIS)

    French, J.B.; Koltun, D.S.

    1975-01-01

    Progress during the past year is summarized for the following areas of nuclear structure and reaction theory: Meson interactions with nucleons and nuclei, including inelastic scattering of pions, three-body theories of scattering and absorption of pions by deuterons, and π-p bremsstrahlung. Theory of the effective interaction, including behavior of the expansion in orders of the reaction matrix. Statistical spectroscopy including fluctuations in energy levels and excitation strengths, and sum rules and strength distributions for various excitation processes, including single-nucleon transfer, β decay and multipole giant resonances. Studies of the inverse scattering problem. Studies of nuclear symmetries, of nuclear clustering, and of general nuclear structure by α-transfer reactions, and of nuclear shapes by (d, 3 He) reactions. (U.S.)

  6. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  7. A comprehensive clinical validation of the nuclear stethoscope

    International Nuclear Information System (INIS)

    Caruana, M.; Jones, R.; Lahiri, A.; Brigden, G.; Rodrigues, E.; Dore, C.; Raftery, E.B.; Medical Research Council, Harrow

    1986-01-01

    Five studies were conducted to examine the degree of variability to be expected during the use of the non-imaging nuclear probe (BIOS Inc.) under a variety of clinical conditions. Comparison of the ejection fraction (EF) readings between the nuclear probe and a gamma camera showed good agreement, with the nuclear probe tending to underestimate lower, and overestimate higher camera EF values. It is concluded that the portable, low cost nuclear probe produces accurate EF measurements when compared with the gamma camera. (author)

  8. The double copy: Bremsstrahlung and accelerating black holes

    CERN Document Server

    Luna, Andres; Nicholson, Isobel; O'Connell, Donal; White, Chris D

    2016-01-01

    Advances in our understanding of perturbation theory suggest the existence of a correspondence between classical general relativity and Yang-Mills theory. A concrete example of this correspondence, which is known as the double copy, was recently introduced for the case of stationary Kerr-Schild spacetimes. Building on this foundation, we examine the simple time-dependent case of an accelerating, radiating point source. The gravitational solution, which generalises the Schwarzschild solution, includes a non-trivial stress-energy tensor. This stress-energy tensor corresponds to a gauge theoretic current in the double copy. We interpret both of these sources as representing the radiative part of the field. Furthermore, in the simple example of Bremsstrahlung, we determine a scattering amplitude describing the radiation, maintaining the double copy throughout. Our results provide the strongest evidence yet that the classical double copy is directly related to the BCJ double copy for scattering amplitudes.

  9. Mixed optical Cherenkov–Bremsstrahlung radiation in vicinity of the Cherenkov cone from relativistic heavy ions: Unusual dependence of the angular distribution width on the radiator thickness

    Energy Technology Data Exchange (ETDEWEB)

    Rozhkova, E.I., E-mail: elenafiks@gmail.com; Pivovarov, Yu.L.

    2016-07-15

    The Cherenkov radiation (ChR) angular distribution is usually described by the Tamm–Frank (TF) theory, which assumes that relativistic charged particle moves uniformly and rectilinearly in the optically transparent radiator. According to the TF theory, the full width at half maximum (FWHM) of the ChR angular distribution inversely depends on the radiator thickness. In the case of relativistic heavy ions (RHI) a slowing-down in the radiator may sufficiently change the angular distribution of optical radiation in vicinity of the Cherenkov cone, since there appears a mixed ChR–Bremsstrahlung radiation. As a result, there occurs a drastic transformation of the FWHM of optical radiation angular distribution in dependence on the radiator thickness: from inversely proportional (TF theory) to the linearly proportional one. In our paper we present the first analysis of this transformation taking account of the gradual velocity decrease of RHI penetrating through a radiator. - Highlights: • Stopping of relativistic heavy ions leads to appearance of a Cherenkov–Bremsstrahlung radiation near the Cherenkov cone. • Mixed Cherenkov–Bremsstrahlung optical radiation FWHM differs from the standard one determined by the Tamm–Frank theory. • The Cherenkov–Bremsstrahlung radiation angular distribution FWHM linearly depends on the radiator thickness.

  10. Channeling and coherent bremsstrahlung effects for relativistic positrons and electrons

    International Nuclear Information System (INIS)

    Walker, R.L.

    1976-01-01

    Channeling of positrons in single crystals of silicon was observed in transmission and scattering measurements for incident energies from 16 to 28 MeV. In addition, the spectral dependence upon crystal orientation of the forward coherent bremsstrahlung produced by beams of 28-MeV positrons and electrons incident upon a 5 μm thick single crystal of silicon was measured with a NaI photon spectrometer. Effects of channeling and perhaps of the nonvalidity of the first Born approximation were observed for beam directions near the [111] axis of the crystal, and coherent peaks near 0.5 MeV were observed for a compound interference direction, in agreement with first-order theoretical calculations. 32 fig

  11. Bremsstrahlung and pair production in crystals at very high energies

    International Nuclear Information System (INIS)

    Nikishov, A.I.

    1981-01-01

    The probabilities for bremsstrahlung and pair production in crystals are discussed under stringent condition when the trajectory of the high-energy electron crosses very many atoms of a crystal row (or plane). It is shown that for sufficiently long path in such conditions the probabilities are described by the formulas for these processes in a strong constant magnetic field exerting on electron the same deflection as the atom row. It turns out that for lead at energy approximately 10 12 eV the radiation length is shortened many hundred times. For greater energies the decrease of probabilities per unit length with increase of energy goes as W varies as Esup(-1/3)

  12. Fast measurement of luminosity at LEP by detecting the single bremsstrahlung photons

    International Nuclear Information System (INIS)

    Bini, C.; De Zorzi, G.; Diambrini Palazzi, G.; Di Cosimo, G.; Di Domenico, A.; Gauzzi, P.; Zanello, D.

    1991-01-01

    Luminosity and beam angular divergence have been measured at LEP with a fast monitor based on the single bremsstrahlung process e + e - → e + e - γ. The photons emitted at the interaction point 1 are detected by an electromagnetic calorimeter: both the photon energy and the impact point are measured. The beam angular divergence and the luminosity are determined in few minutes with a statistical error of 1%. With the present experimental layout the systematic error is of few percent; it would be reduced by performing the measurement on an experimental interaction point. (orig.)

  13. Monte-Carlo calculations of forward directed bremsstrahlung produced by 20 and 45 MeV electrons on tungsten

    International Nuclear Information System (INIS)

    Goosman, D.R.

    1983-01-01

    The SANDYL Monte-Carlo code has been used to calculate the Bremsstrahlung photon production from beams of parallel electrons incident upon three target geometries. These are 20 MeV electrons onto 1 mm of tungsten + 59 mm of Be, which simulates the operating parameters of the FXR electron accelerator at LLNL Bldg. 801, 45 MeV electrons onto 1 mm of tungsten, and finally 45 MeV electrons onto 1 mm of tungsten and 147 mm of Be. The latter two situations simulate possible future modifications to the FXR accelerator. Graphs of the spectral shape of the Bremsstrahlung photons emitted with angles between 0 0 and 1 0 to the electron direction, the angular distribution of photon-MeV, and the dose reduction curves for each of the three geometries are given. The latter dose reduction curves allow one to calculate forward-directed photon fluxes in real-life situations where the electron beam has non-zero angular divergence

  14. Bremsstrahlung X rays from Jovian auroral electrons

    International Nuclear Information System (INIS)

    Barbosa, D.D.

    1990-01-01

    The spectrum of X rays from the planet Jupiter is calculated according to an auroral electron beam model. The electrons are assumed to be accelerated by a field-aligned potential drop and penetrate into the atmosphere as a Maxwellian beam of primaries which are scattered, degraded in energy, and merged with a population of ionization secondaries having a power law energy distribution. The soft X rays observed by the Einstein Observatory satelltie are due to bremsstrahlung from the sedondary electrons in the H 2 atmosphere. A good match to the X ray data is obtained if the power law spectral index of the secondary electrons, γ e , is ≅ 2, yielding a power law slope for the photon flux γ X = γ e + 1 ≅ 3. The X ray intensity is best reconciled with a beam of primaries having a characteristic energy 30-100 keV and penetrating the homopause with an auroral energy flux typically of 10-20 ergs cm -2 s -1 but no greater than 50 ergs cm -2 s -1

  15. Analytic approximate radiation effects due to Bremsstrahlung

    International Nuclear Information System (INIS)

    Ben-Zvi, I.

    2012-01-01

    The purpose of this note is to provide analytic approximate expressions that can provide quick estimates of the various effects of the Bremsstrahlung radiation produced relatively low energy electrons, such as the dumping of the beam into the beam stop at the ERL or field emission in superconducting cavities. The purpose of this work is not to replace a dependable calculation or, better yet, a measurement under real conditions, but to provide a quick but approximate estimate for guidance purposes only. These effects include dose to personnel, ozone generation in the air volume exposed to the radiation, hydrogen generation in the beam dump water cooling system and radiation damage to near-by magnets. These expressions can be used for other purposes, but one should note that the electron beam energy range is limited. In these calculations the good range is from about 0.5 MeV to 10 MeV. To help in the application of this note, calculations are presented as a worked out example for the beam dump of the R and D Energy Recovery Linac.

  16. Analytic approximate radiation effects due to Bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi I.

    2012-02-01

    The purpose of this note is to provide analytic approximate expressions that can provide quick estimates of the various effects of the Bremsstrahlung radiation produced relatively low energy electrons, such as the dumping of the beam into the beam stop at the ERL or field emission in superconducting cavities. The purpose of this work is not to replace a dependable calculation or, better yet, a measurement under real conditions, but to provide a quick but approximate estimate for guidance purposes only. These effects include dose to personnel, ozone generation in the air volume exposed to the radiation, hydrogen generation in the beam dump water cooling system and radiation damage to near-by magnets. These expressions can be used for other purposes, but one should note that the electron beam energy range is limited. In these calculations the good range is from about 0.5 MeV to 10 MeV. To help in the application of this note, calculations are presented as a worked out example for the beam dump of the R&D Energy Recovery Linac.

  17. Nuclear research with the electromagnetic probe. Progress report

    International Nuclear Information System (INIS)

    Meziani, Z.E.

    1992-01-01

    The project discussed in this progress report focusses on understanding the many facets and scales of strongly interacting systems using the electromagnetic probe. On one hand we are investigating the spin properties of the nucleon (proton and neutron) through its fundamental constituents (quarks and gluons). On the other hand we are studying the properties of nucleons in nuclei and the few-body systems. The E142 and the newly approved E143 experiments planned at the Stanford Linear Accelerator Center are designed to provide an answer to the mystery of the missing spin of the proton, while the new letter of intent submitted to SLAC, will investigate the so called Color transparency effect related to the prediction of PQCD for the (e,e'p) quasielastic process in nuclei. Our research involvement at the Continuous Electron Beam Accelerator Facility focusses in Hall A. From the technical point of view we are building the Coemption polarimeter for the Hall A beam line. This device should allow a precise measurement of the electron beam polarization for several approved experiments. From the physics aspect of the project we plan to perform the transverse/longitudinal separation of the nuclear response at high momentum transfer in the quasielastic region, the photodisintegration of deuterium with the measurement of the recoil polarization of the proton and the electromagnetic form factor of few body systems experiment

  18. Angular distribution of thick-target bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on Ag

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, D.; Cavness, B.; Williams, S. [Department of Physics, Angelo State University, San Angelo, Texas 76909 (United States)

    2011-11-15

    Experimental results are presented comparing the intensities of the bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on a thick Ag target, measured at forward angles in the range of 0 degree sign to 55 degree sign . When the data are corrected for attenuation due to photon absorption within the target, the results indicate that the detected radiation is distributed anisotropically only at photon energies k that are approximately equal to the initial energy of the incident electrons E{sub 0}. The results of our experiments suggest that, as k/E{sub 0}{yields} 0, the detected radiation essentially becomes isotropic due primarily to the scattering of electrons within the target. A comparison to the theory of Kissel et al.[At. Data Nucl. Data Tables 28, 381 (1983)] suggests that the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets only when k/E{sub 0}{approx_equal} 1. The experimental data also are in approximate agreement with the angular distribution predictions of the Monte Carlo program penelope.

  19. Tracking of the nuclear wavepacket motion in cyanine photoisomerization by ultrafast pump-dump-probe spectroscopy.

    Science.gov (United States)

    Wei, Zhengrong; Nakamura, Takumi; Takeuchi, Satoshi; Tahara, Tahei

    2011-06-01

    Understanding ultrafast reactions, which proceed on a time scale of nuclear motions, requires a quantitative characterization of the structural dynamics. To track such structural changes with time, we studied a nuclear wavepacket motion in photoisomerization of a prototype cyanine dye, 1,1'-diethyl-4,4'-cyanine, by ultrafast pump-dump-probe measurements in solution. The temporal evolution of wavepacket motion was examined by monitoring the efficiency of stimulated emission dumping, which was obtained from the recovery of a ground-state bleaching signal. The dump efficiency versus pump-dump delay exhibited a finite rise time, and it became longer (97 fs → 330 fs → 390 fs) as the dump pulse was tuned to longer wavelengths (690 nm → 950 nm → 1200 nm). This result demonstrates a continuous migration of the leading edge of the wavepacket on the excited-state potential from the Franck-Condon region toward the potential minimum. A slowly decaying feature of the dump efficiency indicated a considerable broadening of the wavepacket over a wide range of the potential, which results in the spread of a population distribution on the flat S(1) potential energy surface. The rapid migration as well as broadening of the wavepacket manifests a continuous nature of the structural dynamics and provides an intuitive visualization of this ultrafast reaction. We also discussed experimental strategies to evaluate reliable dump efficiencies separately from other ultrafast processes and showed a high capability and possibility of the pump-dump-probe method for spectroscopic investigation of unexplored potential regions such as conical intersections. © 2011 American Chemical Society

  20. The Optical/UV Excess of X-Ray-dim Isolated Neutron Stars. I. Bremsstrahlung Emission from a Strangeon Star Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weiyang; Lu, Jiguang; Men, Yunpeng; Xu, Renxin [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Tong, Hao [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011 (China); Ge, Mingyu [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Zhaosheng, E-mail: r.x.xu@pku.edu.cn [Department of Physics, Xiangtan University, Xiangtan 411105 (China)

    2017-03-01

    X-ray-dim isolated neutron stars (XDINSs) are characterized by Planckian spectra in X-ray bands, but show optical/ultraviolet (UV) excesses: the factors by which the measured photometry exceeds those extrapolated from X-ray spectra. To solve this problem, a radiative model of bremsstrahlung emission from a plasma atmosphere is established in the regime of a strangeon star. A strangeon star atmosphere could simply be regarded as the upper layer of a normal neutron star. This plasma atmosphere, formed and maintained by the interstellar-medium-accreted matter due to the so-called strangeness barrier, is supposed to be of two temperatures. All seven XDINS spectra could be well fitted by the radiative model, from optical/UV to X-ray bands. The fitted radiation radii of XDINSs are from 7 to 13 km, while the modeled electron temperatures are between 50 and 250 eV, except RX J0806.4–4123, with a radiation radius of ∼3.5 km, indicating that this source could be a low-mass strangeon star candidate. This strangeon star model could further be tested by soft X-ray polarimetry, such as the Lightweight Asymmetry and Magnetism Probe, which is expected to be operational on China’s space station around 2020.

  1. Measuring the electron-ion ring parameters by bremsstrahlung

    International Nuclear Information System (INIS)

    Inkin, V.D.; Mozelev, A.A.; Sarantsev, V.P.

    1982-01-01

    A system is described for measuring the number of electrons and ions in the electron-ion rings of a collective heavy ion accelerator. The system operation is based on detecting gamma quanta of bremsstrahlung following the ring electron interaction with the nuclei of neutral atoms and ions at different stages of filling the ring with ions. The radiation detector is a scintillation block - a photomultiplier operating for counting with NaI(Tl) crystal sized 30x30 mm and ensuring the detection efficiency close to unity. The system apparatus is made in the CAMAC standard and rems on-line with the TRA/i miniature computer. The block-diagrams of the system and algorithm of data processing are presented. A conclusion is drawn that the results of measuring the ring parameters with the use of the diagnostics system described are in good agreement within the range of measuring errors with those obtained by means of the diagnostics system employing synchrotron radiation and induction sensors

  2. Bremsstrahlung background and quantitation of thin biological samples

    International Nuclear Information System (INIS)

    Khan, K.M.

    1991-02-01

    An inherent feature of all electron-excited X-ray spectra is the presence of a background upon which the characteristic peaks of interest are superimposed. To extract the x-ray intensity of the characteristics lines of interest, it is necessary to subtract this background, which may be due to both specimen generated Bremsstrahlung and extraneous sources, from a measured x-ray spectrum. Some conventional methods of background subtraction will be briefly reviewed. It has been seen that these conventional methods do not give sufficiently accurate results in biological analysis where the peaks of interest are not well-separated and most of the peaks lie in the region where the background is appreciably curved. An alternative approach of background subtraction for such samples is investigated which involves modelling the background using the currently available knowledge of x-ray physics and energy dispersive detectors. This method is particularly suitable for biological samples as well as other samples having an organic matrix. 6 figs. (author)

  3. Beat-to-beat left ventricular performance in atrial fibrillation: radionuclide assessment with the computerized nuclear probe

    International Nuclear Information System (INIS)

    Schneider, J.; Berger, H.J.; Sands, M.J.; Lachman, A.B.; Zaret, B.L.

    1983-01-01

    There is wide beat-to-beat variability in cycle length and left ventricular performance in patients with atrial fibrillation. In this study, left ventricular ejection fraction and relative left ventricular volumes were evaluated on a beat-to-beat basis with the computerized nuclear probe, an instrument with sufficiently high sensitivity to allow continuous evaluation of the radionuclide time-activity curve. Of 18 patients with atrial fibrillation, 5 had mitral stenosis, 6 had mitral regurgitation, and 7 had coronary artery disease. Fifty consecutive beats were analyzed in each patient. The mean left ventricular ejection fraction ranged from 17 to 51%. There was substantial beat-to-beat variation in cycle length and left ventricular ejection fraction in all patients, including those with marked left ventricular dysfunction. In 14 patients who also underwent multiple gated cardiac blood pool imaging, there was an excellent correlation between mean ejection fraction derived from the nuclear probe and gated ejection fraction obtained by gamma camera imaging (r . 0.90). Based on beat-to-beat analysis, left ventricular function was dependent on relative end-diastolic volume and multiple preceding cycle lengths, but not preceding end-systolic volumes. This study demonstrates that a single value for left ventricular ejection fraction does not adequately characterize left ventricular function in patients with atrial fibrillation. Furthermore, both the mean beat-to-beat and the gated ejection fraction may underestimate left ventricular performance at rest in such patients

  4. Interferometric probes of ultrarelativistic nuclear collisions

    Energy Technology Data Exchange (ETDEWEB)

    Padula, S.S. (Instituto de Fisica Teorica, Sao Paulo (Brazil)); Gyulassy, M. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)

    1991-04-01

    We suggest that pion and kaon interferometry are complementary probes that help differentiate hadronic resonance gas from plasma dynamical models. We also discuss how interferometry could be used to test the presence of resonances at AGS energies. Finally, we study the A dependence of interferometry in the resonance model at 200 A GeV. (orig.).

  5. Interferometric probes of ultrarelativistic nuclear collisions

    International Nuclear Information System (INIS)

    Padula, S.S.; Gyulassy, M.

    1991-01-01

    We suggest that pion and kaon interferometry are complementary probes that help differentiate hadronic resonance gas from plasma dynamical models. We also discuss how interferometry could be used to test the presence of resonances at AGS energies. Finally, we study the A dependence of interferometry in the resonance model at 200 A GeV. (orig.)

  6. Light particle emission as a probe of reaction mechanism and nuclear excitation

    International Nuclear Information System (INIS)

    Guerreau, D.

    1989-01-01

    The central part of these lectures will be dealing with the problem of energy dissipation. A good understanding of the mechanisms for the dissipation requires to study both peripheral and central collisions or, in other words, to look at the impact paramenter dependence. This should also provide valuable information on the time scale. In order to probe the reaction mechanism and nuclear excitation, one of the most powerful tool is unquestionably the observation of light particle emission, including neutrons and charged particles. Several examples will be discussed related to peripheral collisions (the fate of transfer reactions, the excitation energy generation, the production of projectile-like fragments) as well as inner collisions for which extensive studies have demonstrated the strength of intermediate energy heavy ions for the production of very hot nuclei and detailed study of their decay properties

  7. Studies on inner bremsstrahlung from a few β-emitting isotopes

    International Nuclear Information System (INIS)

    Keshava, S.L.; Gopala, K.; Venkataramaiah, P.

    2000-01-01

    Past experimental studies on the inner bremsstrahlung (IB) emission from the forbidden β transitions have shown marked deviations from the theoretical calculations of Lewis and Ford, Ford and Martin, Chang and Falkoff, Madansky and Gebhardt. In this paper we have re-analysed the data of IB emissions from four β-emitting isotopes, namely 89 Sr, 141 Ce, 111 Ag and 99 Tc, whose transitions are classified as forbidden. The raw experimental data already available in the literature are critically examined in the light of relevant statistics in order to arrive at meaningful conclusions. The unfolding of the IB spectra was done following the step-by-step procedure of Liden and Starfelt. The results obtained were different from those reported in the literature. (author)

  8. Angular distribution of the bremsstrahlung emission during lower-hybrid current drive on PLT

    International Nuclear Information System (INIS)

    von Goeler, S.; Stevens, J.; Bernabei, S.

    1985-06-01

    The bremsstrahlung emission from the PLT tokamak during lower-hybrid current drive has been measured as a function of angle between the magnetic field and the emission direction. The emission is peaked strongly in the forward direction, indicating a strong anisotropy of the electron-velocity distribution. The data demonstrate the existence of a nearly flat tail of the velocity distribution, which extends out to approximately 500 keV and which is interpreted as the plateau created by Landau damping of the lower-hybrid waves

  9. Neutrons as a probe

    International Nuclear Information System (INIS)

    Iizumi, Masashi

    1993-01-01

    As an introduction to the symposium a brief overview will be given about the features of neutrons as a probe. First it will be pointed out that the utilization of neutrons as a probe for investigating the structural and dynamical properties of condensed matters is a benign gift eventuated from the release of atomic energy initiated by Enrico Fermi exactly half century ago. Features of neutrons as a probe are discussed in accordance with the four basic physical properties of neutrons as an elementary particle; (1) no electric charge (the interaction with matter is nuclear), (2) the mass of neutron is 1 amu, (3) spin is 1/2 and (4) neutrons have magnetic dipole moment. Overview will be given on the uniqueness of neutrons as a probe and on the variety in the way they are used in the wide research area from the pure science to the industrial applications. (author)

  10. Monte Carlo 20 and 45 MeV Bremsstrahlung and dose-reduction calculations

    Energy Technology Data Exchange (ETDEWEB)

    Goosman, D.R.

    1984-08-14

    The SANDYL electron-photon coupled Monte Carlo code has been compared with previously published experimental bremsstrahlung data at 20.9 MeV electron energy. The code was then used to calculate forward-directed spectra, angular distributions and dose-reduction factors for three practical configurations. These are: 20 MeV electrons incident on 1 mm of W + 59 mm of Be, 45 MeV electrons of 1 mm of W and 45 MeV electrons on 1 mm of W + 147 mm of Be. The application of these results to flash radiography is discussed. 7 references, 12 figures, 1 table.

  11. Monte Carlo 20 and 45 MeV Bremsstrahlung and dose-reduction calculations

    International Nuclear Information System (INIS)

    Goosman, D.R.

    1984-01-01

    The SANDYL electron-photon coupled Monte Carlo code has been compared with previously published experimental bremsstrahlung data at 20.9 MeV electron energy. The code was then used to calculate forward-directed spectra, angular distributions and dose-reduction factors for three practical configurations. These are: 20 MeV electrons incident on 1 mm of W + 59 mm of Be, 45 MeV electrons of 1 mm of W and 45 MeV electrons on 1 mm of W + 147 mm of Be. The application of these results to flash radiography is discussed. 7 references, 12 figures, 1 table

  12. Optimization of the linear induction accelerator construction for maximizing the bremsstrahlung output

    Energy Technology Data Exchange (ETDEWEB)

    Zinchenko, V F; Tulisov, E V; Chlenov, A M; Shiyan, V D [Research Institute of Scientific Instruments, Turaevo-Lytkarino (Russian Federation)

    1997-12-31

    The results of experimental and theoretical optimization of the linear induction accelerator (LIA) design are presented. The major aim of the investigations was to maximize the bremsstrahlung output near the target face. The work was carried out in two stages: l) modernization of the injector module and 2) focusing of the relativistic electron beam (REB) produced at the exit of the accelerating system (AS) in the increasing axial magnetic field. In addition, the methods of diagnostics of angular and energetic parameters of REB based on measurements of radiation dose fields behind the target are described. (author). 2 figs., 4 refs.

  13. Modeling of the electron distribution based on bremsstrahlung emission during lower hybrid current drive on PLT

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, J.E.; von Goeler, S.; Bernabei, S.; Bitter, M.; Chu, T.K.; Efthimion, P.; Fisch, N.; Hooke, W.; Hosea, J.; Jobes, F.

    1985-03-01

    Lower hybrid current drive requires the generation of a high energy electron tail anisotropic in velocity. Measurements of bremsstrahlung emission produced by this tail are compared with the calculated emission from reasonable model distributions. The physical basis and the sensitivity of this modeling process are described and the plasma properties of current driven discharges which can be derived from the model are discussed.

  14. Modeling of the electron distribution based on bremsstrahlung emission during lower hybrid current drive on PLT

    International Nuclear Information System (INIS)

    Stevens, J.E.; von Goeler, S.; Bernabei, S.

    1985-03-01

    Lower hybrid current drive requires the generation of a high energy electron tail anisotropic in velocity. Measurements of bremsstrahlung emission produced by this tail are compared with the calculated emission from reasonable model distributions. The physical basis and the sensitivity of this modeling process are described and the plasma properties of current driven discharges which can be derived from the model are discussed

  15. Super-resolution imaging of a 2.5 kb non-repetitive DNA in situ in the nuclear genome using molecular beacon probes

    Science.gov (United States)

    Ni, Yanxiang; Cao, Bo; Ma, Tszshan; Niu, Gang; Huo, Yingdong; Huang, Jiandong; Chen, Danni; Liu, Yi; Yu, Bin; Zhang, Michael Q; Niu, Hanben

    2017-01-01

    High-resolution visualization of short non-repetitive DNA in situ in the nuclear genome is essential for studying looping interactions and chromatin organization in single cells. Recent advances in fluorescence in situ hybridization (FISH) using Oligopaint probes have enabled super-resolution imaging of genomic domains with a resolution limit of 4.9 kb. To target shorter elements, we developed a simple FISH method that uses molecular beacon (MB) probes to facilitate the probe-target binding, while minimizing non-specific fluorescence. We used three-dimensional stochastic optical reconstruction microscopy (3D-STORM) with optimized imaging conditions to efficiently distinguish sparsely distributed Alexa-647 from background cellular autofluorescence. Utilizing 3D-STORM and only 29–34 individual MB probes, we observed 3D fine-scale nanostructures of 2.5 kb integrated or endogenous unique DNA in situ in human or mouse genome, respectively. We demonstrated our MB-based FISH method was capable of visualizing the so far shortest non-repetitive genomic sequence in 3D at super-resolution. DOI: http://dx.doi.org/10.7554/eLife.21660.001 PMID:28485713

  16. Diagnostics of pre-breakdown light emission in a helium coplanar barrier discharge: the presence of neutral bremsstrahlung

    Science.gov (United States)

    Navrátil, Zdeněk; Morávek, Tomáš; Ráheľ, Jozef; Čech, Jan; Lalinský, Ondřej; Trunec, David

    2017-05-01

    Weak light emission (˜10-3 of active discharge signal; average count rate ˜ 1 photon s-1 nm-1) associated with surface charge relaxation during the dark phase of a helium diffuse coplanar barrier discharge was studied by optical emission spectroscopy, using a technique of phase-resolved single photon counting. The optical emission spectra of the dark phase contained luminescent bands of the dielectrics used (Al2O3, AlN) and spectral lines from the gas constituents (OH*, {{{N}}}2* , {{{N}}}2+* , He*, He{}2* , O*). During the charge relaxation event, a broad continuum appeared in the optical emission spectra, consisting of bremsstrahlung radiation and amplified luminescence of the dielectric barrier. The analysis presented suggests that the bremsstrahlung radiation originated from slow electrons colliding with neutral helium atoms. The fitting procedure we developed reproduced well the observed shape of the continuum. Moreover, it provided a method for the determination of electric field strength in the discharge during this particular phase. The electric field reached 1 kV cm-1 during the charge relaxation event.

  17. Applying the new gamma ray imager diagnostic to measurements of runaway electron Bremsstrahlung radiation in the DIII-D Tokamak (invited)

    International Nuclear Information System (INIS)

    Cooper, C. M.; Pace, D. C.; Paz-Soldan, C.; Eidietis, N. W.; Commaux, N.; Shiraki, D.; Hollmann, E. M.

    2016-01-01

    A new gamma ray imager (GRI) is developed to probe the electron distribution function with 2D spatial resolution during runaway electron (RE) experiments at the DIII-D tokamak. The diagnostic is sensitive to 0.5–100 MeV gamma rays, allowing characterization of the RE distribution function evolution during RE growth and dissipation. The GRI consists of a lead “pinhole camera” mounted on the DIII-D midplane with 123 honeycombed tangential chords 20 cm wide that span the vessel interior. Up to 30 bismuth germanate (BGO) scintillation detectors capture RE bremsstrahlung radiation for Pulse Height Analysis (PHA) capable of discriminating up to 20 000 pulses per second. Digital signal processing routines combining shaping filters are performed during PHA to reject noise and record gamma ray energy. The GRI setup and PHA algorithms will be described and initial data from experiments will be presented. A synthetic diagnostic is developed to generate the gamma ray spectrum of a GRI channel given the plasma information and a prescribed distribution function. Magnetic reconstructions of the plasma are used to calculate the angle between every GRI sightline and orient and discriminate gamma rays emitted by a field-aligned RE distribution function.

  18. Applying the new gamma ray imager diagnostic to measurements of runaway electron Bremsstrahlung radiation in the DIII-D Tokamak (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, C. M., E-mail: coopercm@fusion.gat.com [Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830 (United States); Pace, D. C.; Paz-Soldan, C.; Eidietis, N. W. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Commaux, N.; Shiraki, D. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Hollmann, E. M. [University of California, San Diego, La Jolla, California 92093-0533 (United States)

    2016-11-15

    A new gamma ray imager (GRI) is developed to probe the electron distribution function with 2D spatial resolution during runaway electron (RE) experiments at the DIII-D tokamak. The diagnostic is sensitive to 0.5–100 MeV gamma rays, allowing characterization of the RE distribution function evolution during RE growth and dissipation. The GRI consists of a lead “pinhole camera” mounted on the DIII-D midplane with 123 honeycombed tangential chords 20 cm wide that span the vessel interior. Up to 30 bismuth germanate (BGO) scintillation detectors capture RE bremsstrahlung radiation for Pulse Height Analysis (PHA) capable of discriminating up to 20 000 pulses per second. Digital signal processing routines combining shaping filters are performed during PHA to reject noise and record gamma ray energy. The GRI setup and PHA algorithms will be described and initial data from experiments will be presented. A synthetic diagnostic is developed to generate the gamma ray spectrum of a GRI channel given the plasma information and a prescribed distribution function. Magnetic reconstructions of the plasma are used to calculate the angle between every GRI sightline and orient and discriminate gamma rays emitted by a field-aligned RE distribution function.

  19. Studies of plasma breakdown and electron heating on a 14 GHz ECR ion source through measurement of plasma bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Ropponen, T; Machicoane, G; Leitner, D [National Superconducting Cyclotron Laboratory, MSU, East Lansing, MI 48824 (United States); Tarvainen, O; Toivanen, V; Koivisto, H; Kalvas, T; Peura, P; Jones, P [University of Jyvaeskylae, Department of Physics, PO Box 35 (YFL), 40500 Jyvaeskylae (Finland); Izotov, I; Skalyga, V; Zorin, V [Institute of Applied Physics, RAS, 46 Ulyanov St., 603950 Nizhny Novgorod (Russian Federation); Noland, J, E-mail: tommi.ropponen@gmail.com, E-mail: olli.tarvainen@jyu.fi [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

    2011-10-15

    Temporal evolution of plasma bremsstrahlung emitted by a 14 GHz electron cyclotron resonance ion source (ECRIS) operated in pulsed mode is presented in the energy range 1.5-400 keV with 100 {mu}s resolution. Such a high temporal resolution together with this energy range has never been measured before with an ECRIS. Data are presented as a function of microwave power, neutral gas pressure, magnetic field configuration and seed electron density. The saturation time of the bremsstrahlung count rate is almost independent of the photon energy up to 100 keV and exhibits similar characteristics with the neutral gas balance. The average photon energy during the plasma breakdown is significantly higher than that during the steady state and depends strongly on the density of seed electrons. The results are consistent with a theoretical model describing the evolution of the electron energy distribution function during the preglow transient.

  20. Experimental study of the electron-atom Bremsstrahlung emission in an argon plasma jet

    International Nuclear Information System (INIS)

    Ranson, P.; Vallee, O.; Chapelle, J.

    1977-01-01

    Electron-neutral atom bremsstrahlung is studied between 0.4 μm and 5 μm in a decaying argon plasma jet; in visible and infra-red range, some discrepancies appear between experimental results and theoretical calculations of different authors (Geltman, Stallcop). In the infra-red, the discrepancy can be partly explained because theoretical elastic cross sections are higher than experimental values in the vicinity of the Ramsauer minimum. In the visible range, a very small amount of fast electrons due to superelastic and recombination collisions explain the observed discrepancy [fr

  1. Light meson production and pp-bremsstrahlung at the COSY time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Kuhlmann, E.; Brand, H.; Brand, S.; Cloth, P.; Dahmen, M.; Drueke, V.; Eyrich, W.; Filges, D.; Freiesleben, H.; Fritsche, A.; Kilian, K.; Kirsch, M.; Koch, H.; Kraft, R.A.; Krug, J.; Lange, S.; Machner, H.; Matthaey, H.; Michel, P.; Mirz, R.; Moeller, K.; Morsch, H.P.; Naumann, B.; Naumann, L.; Oelert, W.; Parsch, A.; Paul, N.; Ringe, P.; Roderburg, E.; Roehrich, K.; Roeser, A.; Rogge, M.; Schmidt, G.; Schmidt, M.; Schult, O.; Sefzick, T.; Steinke, M.; Stinzing, F.; Stratmann, R.; Turek, P.; Werding, R.; Wirth, S.

    1993-01-01

    Experiments on light meson production and pp-bremsstrahlung as planned for the initial stage at COSY are discussed. Special emphasis will be placed on near-threshold behaviour where due to kinematics all particles are forced into a rather narrow cone around the beam axis. A specially designed charged particle detector system will be used which not only covers the complete forward hemisphere of 2π in the laboratory system but additionally shows maximum resolution in the extreme forward direction with only moderate cuts in the minimally required energy of all ejectiles. (orig.)

  2. Using a tungsten rollbar to characterize the source spot of a megavoltage bremsstrahlung linac

    International Nuclear Information System (INIS)

    Schach von Wittenau, A.E.; Logan, C.M.; Rikard, R.

    2002-01-01

    In photon teletherapy, the size and functional form of the photon source spot affect both the sharpness of the penumbra of treatment fields and the sharpness of portal images. Photon source spot parameters are also used in photon teletherapy dose calculation codes. A simple method for characterizing the source spot would complement the existing, more involved methods that have been described in the medical physics literature. Such a method, using a rollbar made of tungsten or other high-Z metal, is used in industrial radiography. We describe the use of a tungsten rollbar for characterizing the source spot edge spread function (and thereby the source spot size and shape) of a megavoltage bremsstrahlung photon source. We use Monte Carlo simulations to quantify anticipated experimental artifacts of the method, assuming typical spot sizes for circ-function, Gaussian, and Bennett line shapes. We illustrate the use of the rollbar method by characterizing the source spot of a typical 9 MV linac used for industrial radiography. The source spot is analyzed using two approaches: (a) fitting the rollbar image with analytic functions and (b) using Abel inversion to obtain the cylindrically symmetric spot profile consistent with the measured rollbar image. Monte Carlo simulations, based on a 6 MV photon teletherapy accelerator, suggest that aspects of the method are applicable to medical bremsstrahlung sources

  3. Polarization bremsstrahlung of a hydrogen-like ion in a single crystal

    International Nuclear Information System (INIS)

    Astapenko, V. A.

    2009-01-01

    Polarization bremsstrahlung (PB) that arises when a fast hydrogen-like ion is scattered in a single crystal is investigated theoretically. Four types of the process are analyzed that are caused by virtual excitation of electrons of the target and of the incident particle (IP), as well as by a coherent and incoherent interaction between the IP and the single crystal. The spectral, angular, and velocity (of the IP) characteristics of PB are calculated with regard to the spectral function of a photodetector. Optimal observation conditions and regions in which different types of PB are dominant are determined, and the dependence of these regions on the charge of the IP nucleus and of the target atoms is revealed

  4. Diagnostics of pre-breakdown light emission in a helium coplanar barrier discharge: the presence of neutral bremsstrahlung

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Z.; Morávek, T.; Ráhel’, J.; Čech, J.; Lalinský, Ondřej; Trunec, D.

    2017-01-01

    Roč. 26, č. 5 (2017), s. 1-10, č. článku 055025. ISSN 0963-0252 Institutional support: RVO:68081731 Keywords : dielectric barrier discharge * helium * single photon counting * bremsstrahlung * electric field * backward discharge * surface charge Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.302, year: 2016

  5. Initial results from a multiple monoenergetic gamma radiography system for nuclear security

    Science.gov (United States)

    O'Day, Buckley E.; Hartwig, Zachary S.; Lanza, Richard C.; Danagoulian, Areg

    2016-10-01

    The detection of assembled nuclear devices and concealed special nuclear materials (SNM) such as plutonium or uranium in commercial cargo traffic is a major challenge in mitigating the threat of nuclear terrorism. Currently available radiographic and active interrogation systems use ∼1-10 MeV bremsstrahlung photon beams. Although simple to build and operate, bremsstrahlung-based systems deliver high radiation doses to the cargo and to potential stowaways. To eliminate problematic issues of high dose, we are developing a novel technique known as multiple monoenergetic gamma radiography (MMGR). MMGR uses ion-induced nuclear reactions to produce two monoenergetic gammas for dual-energy radiography. This allows us to image the areal density and effective atomic number (Zeff) of scanned cargo. We present initial results from the proof-of-concept experiment, which was conducted at the MIT Bates Research and Engineering Center. The purpose of the experiment was to assess the capabilities of MMGR to measure areal density and Zeff of container cargo mockups. The experiment used a 3.0 MeV radiofrequency quadrupole accelerator to create sources of 4.44 MeV and 15.11 MeV gammas from the 11B(d,nγ)12C reaction in a thick natural boron target; the gammas are detected by an array of NaI(Tl) detectors after transmission through cargo mockups . The measured fluxes of transmitted 4.44 MeV and 15.11 MeV gammas were used to assess the areal density and Zeff. Initial results show that MMGR is capable of discriminating the presence of high-Z materials concealed in up to 30 cm of iron shielding from low- and mid-Z materials present in the cargo mockup.

  6. Possible experiments to distinguish between different methods of treating the Pauli principle in nuclear potential models

    International Nuclear Information System (INIS)

    Krolle, D.; Assenbaum, H.J.; Funck, C.; Langanke, K.

    1987-01-01

    The finite Pauli repulsion model of Walliser and Nakaichi-Maeda and the orthogonality condition model are two microscopically motivated potential models for the description of nuclear collisions which, however, differ from each other in the way they incorporate antisymmetrization effects into the nucleus-nucleus interaction. We have used α+α scattering at low energies as a tool to distinguish between the two different treatments of the Pauli principle. Both models are consistent with the presently available on-shell (elastic) and off-shell (bremsstrahlung) data. We suggest further measurements of α+α bremsstrahlung including the coplanar laboratory differential cross section in Harvard geometry at α-particle angles of around 27 0 and the γ-decay width of the 4 + resonance at E/sub c.m./ = 11.4 MeV, because in both cases the two models make significantly different predictions

  7. Experimental model of the device for detection of nuclear cycle materials by photoneutron technology

    International Nuclear Information System (INIS)

    Bakalyarov, A.M.; Karetnikov, M.D.; Kozlov, K.N.; Lebedev, V.I.; Meleshko, E.A.; Obinyakov, B.A.; Ostashev, I.E.; Tupikin, N.A.; Yakovlev, G.V.

    2007-01-01

    The inherent complexity of sea container control makes them potentially dangerous for smuggling nuclear materials. The experts believe that only active technologies based on recording the products of induced radiation from sensitive materials might solve the problem. The paper reports on the experimental model of the device on the basis of the electron LINAC U-28 for detection of nuclear materials by photonuclear technology. The preliminary numerical optimization of output units (converter, filter, collimator) for shaping the bremsstrahlung was carried out. The setup of experimental device and initial results of recording the prompt and delayed fission products are discussed

  8. Energetic M1 transitions as a probe of nuclear collectivity at high temperatures

    International Nuclear Information System (INIS)

    Baktash, C.

    1987-01-01

    At ORNL, we have recently utilized the Spin Spectrometer setup to investigate the differential effects of increasing spin and excitation energy on nuclear shape and collectivity in 158 Yb. Along the yrast line of this and other N = 88 nuclei, weakly prolate shapes gradually give way to triaxial, and then finally to non-collective oblate shapes as the spin approaches 40 h-bar. However, above the yrast line, large deformation and collectivity once again sets in. This is evidenced by the emergence of a broad quadrupole structure (E/sub γ/ ≅ 1.2 MeV) in the continuum gamma-ray spectra that grows with increasing temperature. The short (sub ps) lifetimes of these transitions attest to the collective nature of these structures. The emergence and growth of the quadrupole structure at high excitation energies is closely correlated with the appearance of energetic (E/sub γ/ ≅ 2.5 MeV), fast M1 transitions which form another broad structure in the continuum spectra. From the centroid of the M1 bump, a quadrupole deformation parameter of 0.35 is inferred. Because of this sensitivity, these energetic M1 transitions provide a unique probe of nuclear shape in the excitation energy range of ≅ 3 to 10 MeV. 6 refs., 2 figs

  9. Nuclear effects in the Drell-Yan process.

    Energy Technology Data Exchange (ETDEWEB)

    Raufeisen, J. (Jorg)

    2002-01-01

    In the target rest frame and at high energies, Drell-Yan (DY) dilepton production looks like bremsstrahlung of massive photons, rather than parton annihilation. The projectile quark is decomposed into a series of Fock states. Configurations with fixed transverse separations in impact parameter space are interaction eigenstates for p p scattering. The DY cross section can then be expressed in terms of the same color dipole cross section as DIS. We compare calculations in this dipole approach with E772 data and with next-to-leading order parton model calculations. This approach is especially suitable to describe nuclear effects, since it allows one to apply Glauber multiple scattering theory. We go beyond the Glauber eikonal approximation by taking into account transitions between states, which would be eigenstates for a proton target. We calculate nuclear shadowing at large Feynman-x{sub F} for DY in proton-nucleus collisions and compare to E772 data. Nuclear effects on the transverse momentum distribution are also investigated.

  10. Nuclear physics with electromagnetic probes

    International Nuclear Information System (INIS)

    Arruda Neto, J.D.T.

    1986-09-01

    The potentiality of electron accelerators for investigating nuclear structures is presented. Several examples of electron scattering in coincidence and their principal characteristics, are discussed. (M.C.K.) [pt

  11. Update and evaluation of decay data for spent nuclear fuel analyses

    Science.gov (United States)

    Simeonov, Teodosi; Wemple, Charles

    2017-09-01

    Studsvik's approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL) and processed (ESTAR) sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources). Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

  12. Update and evaluation of decay data for spent nuclear fuel analyses

    Directory of Open Access Journals (Sweden)

    Simeonov Teodosi

    2017-01-01

    Full Text Available Studsvik’s approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL and processed (ESTAR sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources. Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

  13. Internal bremsstrahlung accompanying non-unique second-forbidden β-decay of 36Cl

    International Nuclear Information System (INIS)

    Basha, A.M.; Khalil, E.I.; Hussein, M.; Ragab, H.S.; El-Konsol, S.

    1991-01-01

    The inner Bremsstrahlung spectrum (I.B.) associated with the non-unique second forbidden β-transition of 36 Cl was measured using a single channel NaI (Tl) scintillation spectrometer. After making all the necessary corrections, the experimental results were compared with the corresponding theoretical distributions due to the KUB, Lewis and Ford, Nilsson, Ford and Martin and Chang and Falkoff. Also a comparison with those calculated according to Nilsson theory after applying the shape correction factor (M. KUB) was done. The measured spectrum is found to show fairly good agreement with M. KUB theory and is found to deviate thereafter from all five theories. (orig.)

  14. Dose estimative in operators during petroleum wells logging with nuclear wireless probes through computer modelling; Estimativa da dose em operadores durante procedimentos de perfilagem de pocos de petroleo com sondas wireless nucleares atraves de modelagem computacional

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Edmilson Monteiro de; Silva, Ademir Xavier da; Lopes, Ricardo T., E-mail: emonteiro@nuclear.ufrj.b, E-mail: ademir@nuclear.ufrj.b, E-mail: ricardo@lin.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Lima, Inaya C.B., E-mail: inaya@lin.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Instituto Politecnico do Rio de Janeiro (IPRJ/UERJ), Nova Friburgo, RJ (Brazil); Correa, Samanda Cristine Arruda, E-mail: scorrea@cnen.gov.b [Comissao Nacional de Energia Nuclear (DIAPI/CGMI/CNEN), Rio de Janeiro, RJ (Brazil); Rocha, Paula L.F., E-mail: ferrucio@acd.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ)., RJ (Brazil). Dept. de Geologia

    2011-10-26

    This paper evaluates the absorbed dose and the effective dose on operators during the petroleum well logging with nuclear wireless that uses gamma radiation sources. To obtain the data, a typical scenery of a logging procedure will be simulated with MCNPX Monte Carlo code. The simulated logging probe was the Density Gamma Probe - TRISOND produced by Robertson Geolloging. The absorbed dose values were estimated through the anthropomorphic simulator in male voxel MAX. The effective dose values were obtained using the ICRP 103

  15. Probing WWγ and WWγγ couplings with high energy photon beams

    International Nuclear Information System (INIS)

    Choi, S.Y.; Schrempp, F.

    1991-12-01

    We examine the potential of a future 500 GeV linear e + e - collider for probing anomalous WW γ and WW γγ couplings in the so-called γ(γ)model, corresponding to colliding γe and γγ beams from Compton backscattering of laser light. We consider in detail the 'minimal' set (k γ , λ γ ) of CP conserving anomalous couplings and present first results for the CP violating 'partner' couplings (anti K γ , anti l γ ) as well. The reactions under consideration are γe → Wν, γγ → W + W - and, as a reference, also e + e - → W + W - . We discuss the impact of both circular polarization of laser photons and polarized e(anti e) beams. Photon 'beams' due to classical Bremsstrahlung are also studied for comparison. We analyze in detail, how changes of the assumed machine parameters, cuts and systematic errors affect the sensitivity to the anomalous couplings. (orig.)

  16. Flexible position probe assembly

    International Nuclear Information System (INIS)

    Schmitz, J.J.

    1977-01-01

    The combination of a plurality of tubular transducer sections and a flexible supporting member extending through the tubular transducer sections forms a flexible elongated probe of a design suitable for monitoring the level of an element, such as a nuclear magnetically permeable control rod or liquid. 3 claims, 23 figures

  17. Groomed jets in heavy-ion collisions: sensitivity to medium-induced bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Mehtar-Tani, Yacine [Institute of Nuclear Theory, University of Washington,Seattle, WA 98195-1550 (United States); Tywoniuk, Konrad [Theoretical Physics Department, CERN,1211 Geneva 23 (Switzerland)

    2017-04-21

    We argue that contemporary jet substructure techniques might facilitate a more direct measurement of hard medium-induced gluon bremsstrahlung in heavy-ion collisions, and focus specifically on the “soft drop declustering” procedure that singles out the two leading jet substructures. Assuming coherent jet energy loss, we find an enhancement of the distribution of the energy fractions shared by the two substructures at small subjet energy caused by hard medium-induced gluon radiation. Departures from this approximation are discussed, in particular, the effects of colour decoherence and the contamination of the grooming procedure by soft background. Finally, we propose a complementary observable, that is the ratio of the two-pronged probability in Pb-Pb to proton-proton collisions and discuss its sensitivity to various energy loss mechanisms.

  18. Groomed jets in heavy-ion collisions: sensitivity to medium-induced bremsstrahlung

    CERN Document Server

    Mehtar-Tani, Yacine

    2017-04-21

    We argue that contemporary jet substructure techniques might facilitate a more direct measurement of hard medium-induced gluon bremsstrahlung in heavy-ion collisions, and focus specifically on the "soft drop declustering" procedure that singles out the two leading jet substructures. Assuming coherent jet energy loss, we find an enhancement of the distribution of the energy fractions shared by the two substructures at small subjet energy caused by hard medium-induced gluon radiation. Departures from this approximation are discussed, in particular, the effects of colour decoherence and the contamination of the grooming procedure by soft background. Finally, we propose a complementary observable, that is the ratio of the two-pronged probability in Pb-Pb to proton-proton collisions and discuss its sensitivity to various energy loss mechanisms.

  19. Groomed jets in heavy-ion collisions: sensitivity to medium-induced bremsstrahlung

    Science.gov (United States)

    Mehtar-Tani, Yacine; Tywoniuk, Konrad

    2017-04-01

    We argue that contemporary jet substructure techniques might facilitate a more direct measurement of hard medium-induced gluon bremsstrahlung in heavy-ion collisions, and focus specifically on the "soft drop declustering" procedure that singles out the two leading jet substructures. Assuming coherent jet energy loss, we find an enhancement of the distribution of the energy fractions shared by the two substructures at small subjet energy caused by hard medium-induced gluon radiation. Departures from this approximation are discussed, in particular, the effects of colour decoherence and the contamination of the grooming procedure by soft background. Finally, we propose a complementary observable, that is the ratio of the two-pronged probability in Pb-Pb to proton-proton collisions and discuss its sensitivity to various energy loss mechanisms.

  20. Groomed jets in heavy-ion collisions: sensitivity to medium-induced bremsstrahlung

    International Nuclear Information System (INIS)

    Mehtar-Tani, Yacine; Tywoniuk, Konrad

    2017-01-01

    We argue that contemporary jet substructure techniques might facilitate a more direct measurement of hard medium-induced gluon bremsstrahlung in heavy-ion collisions, and focus specifically on the “soft drop declustering” procedure that singles out the two leading jet substructures. Assuming coherent jet energy loss, we find an enhancement of the distribution of the energy fractions shared by the two substructures at small subjet energy caused by hard medium-induced gluon radiation. Departures from this approximation are discussed, in particular, the effects of colour decoherence and the contamination of the grooming procedure by soft background. Finally, we propose a complementary observable, that is the ratio of the two-pronged probability in Pb-Pb to proton-proton collisions and discuss its sensitivity to various energy loss mechanisms.

  1. Probing cell mechanical properties with microfluidic devices

    Science.gov (United States)

    Rowat, Amy

    2012-02-01

    Exploiting flow on the micron-scale is emerging as a method to probe cell mechanical properties with 10-1000x advances in throughput over existing technologies. The mechanical properties of cells and the cell nucleus are implicated in a wide range of biological contexts: for example, the ability of white blood cells to deform is central to immune response; and malignant cells show decreased stiffness compared to benign cells. We recently developed a microfluidic device to probe cell and nucleus mechanical properties: cells are forced to deform through a narrow constrictions in response to an applied pressure; flowing cells through a series of constrictions enables us to probe the ability of hundreds of cells to deform and relax during flow. By tuning the constriction width so it is narrower than the width of the cell nucleus, we can specifically probe the effects of nuclear physical properties on whole cell deformability. We show that the nucleus is the rate-limiting step in cell passage: inducing a change in its shape to a multilobed structure results in cells that transit more quickly; increased levels of lamin A, a nuclear protein that is key for nuclear shape and mechanical stability, impairs the passage of cells through constrictions. We are currently developing a new class of microfluidic devices to simultaneously probe the deformability of hundreds of cell samples in parallel. Using the same soft lithography techniques, membranes are fabricated to have well-defined pore distribution, width, length, and tortuosity. We design the membranes to interface with a multiwell plate, enabling simultaneous measurement of hundreds of different samples. Given the wide spectrum of diseases where altered cell and nucleus mechanical properties are implicated, such a platform has great potential, for example, to screen cells based on their mechanical phenotype against a library of drugs.

  2. Measurements of bremsstrahlung spectra of Lanzhou ECR Ion Source No. 3 (LECR3)

    International Nuclear Information System (INIS)

    Zhao, H.Y.; Zhao, H.W.; Ma, X.W.; Zhang, S.F.; Feng, W.T.; Zhu, X.L.; Zhang, Z.M.; He, W.; Sun, L.T.; Feng, Y.C.; Cao, Y.; Li, J.Y.; Li, X.X.; Wang, H.; Ma, B.H.

    2006-01-01

    In order to diagnose the electron cyclotron resonance (ECR) plasma, electron bremsstrahlung spectra were measured by a HPGe detector on Lanzhou ECR Ion Source No. 3 at IMP. The ion source was operated with argon under various working conditions, including different microwave power, mixing gas, extraction high voltage (HV), and so on. Some of the measured spectra are presented in this article. The dependence of energetic electron population on mixing gas and extraction HV is also described. Additionally, we are looking forward to further measurements on SECRAL (Superconducting ECR Ion Source with Advanced design at Lanzhou)

  3. 33S NMR cryogenic probe for taurine detection

    Science.gov (United States)

    Hobo, Fumio; Takahashi, Masato; Maeda, Hideaki

    2009-03-01

    With the goal of a S33 nuclear magnetic resonance (NMR) probe applicable to in vivo NMR on taurine-biological samples, we have developed the S33 NMR cryogenic probe, which is applicable to taurine solutions. The NMR sensitivity gain relative to a conventional broadband probe is as large as 3.5. This work suggests that improvements in the preamplifier could allow NMR measurements on 100 μM taurine solutions, which is the level of sensitivity necessary for biological samples.

  4. X-ray generation from Bremsstrahlung effect using stainless steel target

    International Nuclear Information System (INIS)

    Siti Aiasah Hashim; Shari Jahar; Leo Kee Wah; Muhammad Zahidee Taat

    2004-01-01

    X-ray radiation is produced when high energy electron interacts with metals. This process is known as Bremsstrahlung. In commercial electron beam irradiator, this process may be utilized to serve irradiation of thick products with lower dose requirement such disinfestation of fruits, delaying ripening and medical product sterilization. Initial experiment was carried out to measure the amount of x-ray radiation produced by using a simple converter. In this experiment, the target material is the stainless steel beam shutter that is normally used to protect the window. The maximum energy for the Eps 3000 is 3 MeV and was used generate the x-ray radiation. The dose was measure using CTA film and analyzed using UV spectrophotometer. The results obtained showed that sufficient amount of x-ray dose can be generated for low dose irradiation by using this simple set up. (Author)

  5. Tomographic bremsstrahlung imaging with yttrium-90 in the context of radioembolisation of liver tumors; Tomografische Bildgebung mit Yttrium-90-Bremsstrahlung im Rahmen der Radioembolisation von Lebertumoren

    Energy Technology Data Exchange (ETDEWEB)

    Grosser, Oliver Stephan

    2013-04-12

    Establish tomographic Bremsstrahlung SPECT imaging (BSPECT) for the clinical validation of Selective Internal Radiotherapy (SIRT) with Yttrium-90 ({sup 90}Y) labelled microspheres. Various energy ranges (75 ± 3.8 keV; 135 ± 6.8 keV; 167 ± 8.4 keV) and the summation window were studied to see if they were suitable for BSPECT. To this end, clinically available reconstruction techniques were analysed for their suitability for BSPECT. The tomographic examinations were performed on a cylindrical phantom filled with spheres of different diameters d = [28; 35; 40; 50; 60] mm in a non-active waterfilled background. The spheres were filled with identical {sup 90}Y activity concentration (AC). Measurements were conducted at AC = [14.58; 5.20; 1.98; 0.66] MBq/cm{sup 3}. The BSPECT were reconstructed with filtered back-projection (FBP), a 2D Ordered-Subset Expectation Maximisation Algorithm (2D-OSEM) and a 3D Geometric Mean Algorithm (3D-GMA). Evaluation was made visually and on the basis of objective performance parameters such as contrast, signal-to-noise ratio (SNR) and image noise. While the 75 keV ± 3.8 keV window was identified as suitable for the BSPECT, limitations were revealed as to use of different implementations of the Point Spread Function (PSF). It was found for all reconstruction techniques that, at a given sphere diameter, there existed a linear relationship between the AC in the spheres and the reconstructed pulse rate per volume element. The recovery effect was verified for small spheres. The iterative techniques were found to be suitable for the BSPECT at all AC. At low AC, the 3D-GMA exhibited the least noise and the highest SNR. The FBP turned out to be entirely inappropriate for the BSPECT. The narrow energy window in which the bremsstrahlung interferes with the characteristic X-radiation of lead can be used for BSPECT. In this approach, the tomographic data reconstructed with different algorithms exhibited a varying image quality, with the iterative

  6. Bremsstrahlung spectra for Al, Cs, and Au atoms in high-temperature, high-density plasmas

    International Nuclear Information System (INIS)

    Kim, L.; Pratt, R.H.; Tseng, H.K.

    1985-01-01

    Results are presented from a numerical calculation for the bremsstrahlung spectrum and Gaunt factors of Al, Cs, and Au atoms in high-temperature (-T), high-density (-rho) plasmas. Plasma temperatures kT = 0.1 and 1.0 keV and plasma densities rho = rho 0 (the normal solid density) and rho = 100rho 0 are considered. This allows us to determine the generality and identify the origins of features which we had previously identified in calculations for Cs. We also now present results for the total energy loss of an electron in such a plasma. We use a relativistic multipole code which treats the bremsstrahlung process as a single-electron transition in a static screened central potential. We take for the static potential corresponding to an atom in a hot dense plasma the finite-temperature, finite-density Thomas-Fermi model. This approach corresponds to an average atom in local thermodynamic equilibrium. In comparison to isolated-neutral-atom results we observe general suppression of cross sections and a particular suppression in the tip region of the spectrum. Within this model, both superscreening and shape resonances are found in the circumstances of extreme density. At more normal densities and except for the soft-photon end, the spectrum at these energies for an atom in a hot plasma (characterized by an average degree of ionization) can be well represented by the spectrum of the corresponding isolated ion, which has a similar potential shape at the distances which characterize the process

  7. Coherent bremsstrahlung and channeling radiation from electrons of one to three MeV in silicon and gold

    International Nuclear Information System (INIS)

    Watson, J.E.

    1981-01-01

    The observation of sharp peaks in the x-ray spectrum from 1 to 3 MeV electrons striking thin single crystals of silicon and gold is reported. These peaks were observed in the range 1 to 25 keV. The peaks are of two different origins, both direct results of the periodic nature of the target crystals. The first kind of radiation is caused by the interference of incoming and scattered electron wave functions. Because of the periodicity of the target material there is a coherence effect for certain bremsstrahlung wave vectors. This coherent bremsstrahlung, though well known at very high electron energies, has never been adequately studied at electron energies below several hundred MeV. Detailed agreement between theoretical prediction and observation in silicon is shown. The second kind of radiation is caused by electrons channeled along major crystal axes. The electrons enter certain quantized orbits as they channel and may emit photons as a consequence of transitions between the various orbits. Observations of channeling radiation for various crystal axes in silicon are presented. Both phenomena were observed in gold, the first such observation for any metallic target

  8. Initial studies of Bremsstrahlung energy deposition in small-bore superconducting undulator structures in linac environments

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, T.; Tatchyn, R. [Stanford Univ., CA (United States)

    1995-12-31

    One of the more promising technologies for developing minimal-length insertion devices for linac-driven, single-pass Free Electron Lasers (FELs) operating in the x-ray range is based on the use of superconducting (SC) materials. In recent FEL simulations, for example, a bifilar helical SC device with a 2 cm period and 1.8 T field was found to require a 30 m saturation length for operation at 1.5{Angstrom} on a 15 GeV linac, more than 40% shorter than an alternative hybrid/permanent magnet (hybrid/PM) undulator. AT the same time, however, SC technology is known to present characteristic difficulties for insertion device design, both in engineering detail and in operation. Perhaps the most critical problem, as observed, e.g., by Madey and co-workers in their initial FEL experiments, was the frequent quenching induced by scattered electrons upstream of their (bifilar) device. Postulating that this quenching was precipitated by directly-scattered or bremsstrahlung-induced particle energy deposited into the SC material or into material contiguous with it, the importance of numerical and experimental characterizations of this phenomenon for linac-based, user-facility SC undulator design becomes evident. In this paper we discuss selected prior experimental results and report on initial EGS4 code studies of scattered and bremsstrahlung induced particle energy deposition into SC structures with geometries comparable to a small-bore bifilar helical undulator.

  9. Calculation of Bremsstrahlung radiation of electrons on atoms in wide energy range of photons

    CERN Document Server

    Romanikhin, V P

    2002-01-01

    The complete spectra of the Bremsstrahlung radiation on the krypton atoms within the range of the photon energies of 10-25000 eV and lanthanum near the potential of the 4d-shell ionization is carried out. The atoms summarized polarizability is calculated on the basis of the simple semiclassical approximation of the local electron density and experimental data on the photoabsorption. The comparison with the calculational results is carried out through the method of distorted partial waves (PDWA) for Kr and with the experimental data on La

  10. Magnetic nanostructures: radioactive probes and recent developments

    International Nuclear Information System (INIS)

    Prandolini, M J

    2006-01-01

    The miniaturization of magnetic sensors and storage devices down to the nano-scale leads to drastic changes in magnetic phenomena compared with the same devices with a larger size. Excited-nuclear-probe (radioactive probe) techniques are ideal for investigating these new magnetic nanostructures. By observing the magnetic hyperfine fields (and in some cases the electric-field-gradients (EFGs)) at the nuclei of radioactive probes, microscopic information about the magnetic environment of the probes is acquired. The magnetic hyperfine field is particularly sensitive to the s-spin polarization of the conduction electrons and to the orbital magnetic moment of the probe atom. Three methods of inserting radioactive probes into magnetic nanostructures are presented; neutron activation, recoil implantation and 'soft-landing', followed by descriptions of their application to selected examples. In some cases, these methods offer the simultaneous creation and observation of new magnetic materials at the atomic scale. This review focuses firstly on the induced magnetism in noble-metal spacer layers between either ferromagnetic (FM) or FM/antiferromagnetic (AFM) layers in a trilayer structure. Using the method of low-temperature nuclear orientation, the s-spin polarization of noble-metal probes was measured and was found to be very sensitive to the magnetic properties at both the FM and AFM interfaces. Secondly, the recoil implantation of radioactive Fe probes into rare-earth hosts and d-band alloys and subsequent measurement using time-differential perturbed angular distribution offer the possibility of controlling the chemical composition and number of nearest-neighbours. This method was used to prepare local 3d-magnetic clusters in a non-magnetic matrix and to observe their magnetic behaviour. Finally, non-magnetic radioactive probes were 'soft-landed' onto Ni surfaces and extremely lattice-expanded ultrathin Ni films. By measuring the magnetic hyperfine fields and EFGs at

  11. Electron, electron-bremsstrahlung and proton depth-dose data for space-shielding applications

    Science.gov (United States)

    Seltzer, S. M.

    1979-01-01

    A data set has been developed, consisting of depth-dose distributions for omni-directional electron and proton fluxes incident on aluminum shields. The principal new feature of this work is the accurate treatment, based on detailed Monte Carlo calculations, of the electron-produced bremsstrahlung component. Results covering the energy region of interest in space-shielding calculations have been obtained for the absorbed dose (a) as a function of depth in a semi-infinite medium, (b) at the edge of slab shields, and (c) at the center of a solid sphere. The dose to a thin tissue-equivalent detector was obtained as well as that in aluminum. Various results and comparisons with other work are given.

  12. Hyperpolarized NMR Probes for Biological Assays

    Directory of Open Access Journals (Sweden)

    Sebastian Meier

    2014-01-01

    Full Text Available During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments.

  13. Nuclear Enterprises portable dose rate meter type PDR4 and external probes types BP1/1, BP8 and GP9

    International Nuclear Information System (INIS)

    Burgess, P.H.; Iles, W.J.

    1979-08-01

    The performance characteristics of Nuclear Enterprises Portable Dose Rate Meter Type PDR4 are evaluated under the headings: general description, facilities and controls, radiation characteristics, electrical characteristics, environmental characteristics, mechanical characteristics, the manual, summary of performance, and conclusions. Results of an investigation of the radiation characteristics of the external probes Type BP1/1, Type BP8, and Type GP9 are also detailed. (U.K.)

  14. In Situ Live-Cell Nucleus Fluorescence Labeling with Bioinspired Fluorescent Probes.

    Science.gov (United States)

    Ding, Pan; Wang, Houyu; Song, Bin; Ji, Xiaoyuan; Su, Yuanyuan; He, Yao

    2017-08-01

    Fluorescent imaging techniques for visualization of nuclear structure and function in live cells are fundamentally important for exploring major cellular events. The ideal cellular labeling method is capable of realizing label-free, in situ, real-time, and long-term nucleus labeling in live cells, which can fully obtain the nucleus-relative information and effectively alleviate negative effects of alien probes on cellular metabolism. However, current established fluorescent probes-based strategies (e.g., fluorescent proteins-, organic dyes-, fluorescent organic/inorganic nanoparticles-based imaging techniques) are unable to simultaneously realize label-free, in situ, long-term, and real-time nucleus labeling, resulting in inevitable difficulties in fully visualizing nuclear structure and function in live cells. To this end, we present a type of bioinspired fluorescent probes, which are highly efficacious for in situ and label-free tracking of nucleus in long-term and real-time manners. Typically, the bioinspired polydopamine (PDA) nanoparticles, served as fluorescent probes, can be readily synthesized in situ within live cell nucleus without any further modifications under physiological conditions (37 °C, pH ∼7.4). Compared with other conventional nuclear dyes (e.g., propidium iodide (PI), Hoechst), superior spectroscopic properties (e.g., quantum yield of ∼35.8% and high photostability) and low cytotoxicity of PDA-based probes enable long-term (e.g., 3 h) fluorescence tracking of nucleus. We also demonstrate the generality of this type of bioinspired fluorescent probes in different cell lines and complex biological samples.

  15. Very high energy probes of the quark-gluon plasma

    International Nuclear Information System (INIS)

    Ludlam, T.; Paige, F.; Madansky, L.

    1984-01-01

    Among the penetrating probes of nuclear matter the most frequently discussed have been those which involve the detection of photons or leptons with m/sub T/ approx. = P/sub T/ < 3 GeV. This is the expected range of emission from a hot, thermalized plasma of quarks and gluons. The suggestion has been made that in very high energy collisions of nuclei the properties of high P/sub T/ jets may also reflect the characteristics of the nuclear medium through which the parent partons have propagated just after the collision. In this note we expand on the possible uses of such a probe

  16. Nuclear power in space. Use of reactors and radioactive substances as power sources in satellites and space probes

    International Nuclear Information System (INIS)

    Hoestbaeck, Lars

    2008-11-01

    Today solar panels are the most common technique to supply power to satellites. Solar panels will work as long as the power demand of the satellite is limited and the satellite can be equipped with enough panels, and kept in an orbit that allows enough sunlight to hit the panels. There are various types of space missions that do not fulfil these criteria. With nuclear power these types of missions can be powered regardless of the sunlight and as early as 1961 the first satellite with a nuclear power source was placed in orbit. Out of seventy known space missions that has made use of nuclear power, ten have had some kind of failure. In no case has the failure been associated with the nuclear technology used. This report discusses to what degree satellites with nuclear power are a source for potential radioactive contamination of Swedish territory. It is not a discussion for or against nuclear power in space. Neither is it an assessment of consequences if radioactive material from a satellite would reach the earth's surface. Historically two different kinds of Nuclear Power Sources (NPS) have been used to generate electric power in space. The first is the reactor where the energy is derived from nuclear fission of 235 U and the second is the Radioisotope Thermoelectric Generator (RTG) where electricity is generated from the heat of naturally decaying radionuclides. NPS has historically only been used in space by United States and the Soviet Union (and in one failing operation Russia). Nuclear Power Sources have been used in three types of space objects: satellites, space probes and moon/Mars vehicles. USA has launched one experimental reactor into orbit, all other use of NPS by the USA has been RTG:s. The Soviet Union, in contrast, only launched a few RTG:s but nearly forty reactors. The Soviet use of NPS is less transparent than the use in USA and some data published on Soviet systems are more or less well substantiated assessments. It is likely that also future

  17. Practical reconstruction protocol for quantitative 90Y bremsstrahlung SPECT/CT

    International Nuclear Information System (INIS)

    Siman, W.; Mikell, J. K.; Kappadath, S. C.

    2016-01-01

    Purpose: To develop a practical background compensation (BC) technique to improve quantitative 90 Y-bremsstrahlung single-photon emission computed tomography (SPECT)/computed tomography (CT) using a commercially available imaging system. Methods: All images were acquired using medium-energy collimation in six energy windows (EWs), ranging from 70 to 410 keV. The EWs were determined based on the signal-to-background ratio in planar images of an acrylic phantom of different thicknesses (2–16 cm) positioned below a 90 Y source and set at different distances (15–35 cm) from a gamma camera. The authors adapted the widely used EW-based scatter-correction technique by modeling the BC as scaled images. The BC EW was determined empirically in SPECT/CT studies using an IEC phantom based on the sphere activity recovery and residual activity in the cold lung insert. The scaling factor was calculated from 20 clinical planar 90 Y images. Reconstruction parameters were optimized in the same SPECT images for improved image quantification and contrast. A count-to-activity calibration factor was calculated from 30 clinical 90 Y images. Results: The authors found that the most appropriate imaging EW range was 90–125 keV. BC was modeled as 0.53× images in the EW of 310–410 keV. The background-compensated clinical images had higher image contrast than uncompensated images. The maximum deviation of their SPECT calibration in clinical studies was lowest (<10%) for SPECT with attenuation correction (AC) and SPECT with AC + BC. Using the proposed SPECT-with-AC + BC reconstruction protocol, the authors found that the recovery coefficient of a 37-mm sphere (in a 10-mm volume of interest) increased from 39% to 90% and that the residual activity in the lung insert decreased from 44% to 14% over that of SPECT images with AC alone. Conclusions: The proposed EW-based BC model was developed for 90 Y bremsstrahlung imaging. SPECT with AC + BC gave improved lesion detectability and activity

  18. Angular distributions of absorbed dose of Bremsstrahlung and secondary electrons induced by 18-, 28- and 38-MeV electron beams in thick targets.

    Science.gov (United States)

    Takada, Masashi; Kosako, Kazuaki; Oishi, Koji; Nakamura, Takashi; Sato, Kouichi; Kamiyama, Takashi; Kiyanagi, Yoshiaki

    2013-03-01

    Angular distributions of absorbed dose of Bremsstrahlung photons and secondary electrons at a wide range of emission angles from 0 to 135°, were experimentally obtained using an ion chamber with a 0.6 cm(3) air volume covered with or without a build-up cap. The Bremsstrahlung photons and electrons were produced by 18-, 28- and 38-MeV electron beams bombarding tungsten, copper, aluminium and carbon targets. The absorbed doses were also calculated from simulated photon and electron energy spectra by multiplying simulated response functions of the ion chambers, simulated with the MCNPX code. Calculated-to-experimental (C/E) dose ratios obtained are from 0.70 to 1.57 for high-Z targets of W and Cu, from 15 to 135° and the C/E range from 0.6 to 1.4 at 0°; however, the values of C/E for low-Z targets of Al and C are from 0.5 to 1.8 from 0 to 135°. Angular distributions at the forward angles decrease with increasing angles; on the other hand, the angular distributions at the backward angles depend on the target species. The dependences of absorbed doses on electron energy and target thickness were compared between the measured and simulated results. The attenuation profiles of absorbed doses of Bremsstrahlung beams at 0, 30 and 135° were also measured.

  19. Further investigating the determination of phosphorus in plants by INAA using bremsstrahlung measurement

    International Nuclear Information System (INIS)

    Matsubara, T.C.M.; Bacchi, M.A.; De Nadai Fernandes, E.A.

    2012-01-01

    Phosphorus is an essential element for plants and animals, playing a fundamental role in the production of biochemical energy. Despite its relevance, phosphorus is not commonly determined by instrumental neutron activation analysis (INAA), because 32 P does not emit gamma-rays in its decay. There are alternative methods for the determination of phosphorus by INAA, such as the use of beta counting or the measurement of bremsstrahlung originated from the high energy beta particle from 32 P. Here the determination of phosphorus in plant materials by measuring the bremsstrahlung production was further investigated, to optimize an analytical protocol for minimizing interferences and overcoming the poor specificity. Eight certified reference materials of plant matrices with phosphorus ranging between 171 and 5,180 mg kg -1 were irradiated at a thermal neutron flux of 9.5 x 10 12 cm -2 s -1 and measured with a HPGe detector at decay times varying from 7 to 60 days. Phosphorus solutions added to a certified reference material at three levels were used for calibration. Counts accumulated in the baseline at four different regions of the gamma-ray spectra were tested for the determination of phosphorus, with better results for the 100 keV region. The Compton scattering contribution in the selected range was discounted using an experimental peak-to-Compton factor and the net areas of all peaks in the spectra with energies higher than 218 keV, i.e. Compton edge above 100 keV. Amongst the interferences investigated, the production of 32 P from sulfur, and the contribution of Compton scattering should be considered for producing good results. (author)

  20. Internal bremsstrahlung from 89Sr and 90Sr

    International Nuclear Information System (INIS)

    Sayibaba, T.; Narasimha Murity, K.; Rao, C.R.; Satyaprakash; Gubbi, G.K.

    1987-01-01

    The internal bremsstrahlung (IB) spectra emitted in the beta-decays of 89 Sr and 90 Sr were measured with a HPGe detector and a multichannel analyser along with a standard geometrical set-up. Sufficient care has been taken to avoid spurious effects. After making all the necessary corrections, the experimental results were compared with the corresponding theoretical distributions due to Knipp and Uhlenbeck and Bloch (KUB), Lewis and Ford, Nilsson, and also due to Ford and Martin (detour theory). The total IB yields of intensity and energy from each of the isotopes in the investigated energy regions are also determined and compared with the corresponding theoretical values. The present results of IB from 89 Sr are satisfactorily accounted for by the KUB theory. In the case of 90 Sr the experimental results of IB coincide with the Coulomb-corrected theoretical distibution due to Nilsson in the energy range from 60 keV to 110 keV and Beyond 110 keV, they are found to be in excess over Nilsson's theory as well as the detour theory due to Ford and Martin up to the maximum photon energy studied, namely 350 keV

  1. Hard probes in heavy ion collisions at the LHC: PDFs, shadowing and $pA$ collisions

    CERN Document Server

    Accardi, Alberto; Botje, M.; Brodsky, S.J.; Cole, B.; Eskola, K.J.; Fai, George I.; Frankfurt, L.; Fries, R.J.; Geist, Walter M.; Guzey, V.; Honkanen, H.; Kolhinen, V.J.; Kovchegov, Yu.V.; McDermott, M.; Morsch, A.; Qiu, Jian-wei; Salgado, C.A.; Strikman, M.; Takai, H.; Tapprogge, S.; Vogt, R.; Zhang, X.f.

    2003-01-01

    This manuscript is the outcome of the subgroup ``PDFs, shadowing and $pA$ collisions'' from the CERN workshop ``Hard Probes in Heavy Ion Collisions at the LHC''. In addition to the experimental parameters for $pA$ collisions at the LHC, the issues discussed are factorization in nuclear collisions, nuclear parton distributions (nPDFs), hard probes as the benchmark tests of factorization in $pA$ collisions at the LHC, and semi-hard probes as observables with potentially large nuclear effects. Also, novel QCD phenomena in $pA$ collisions at the LHC are considered. The importance of the $pA$ program at the LHC is emphasized.

  2. Quantitative microanalysis with a nuclear microprobe

    International Nuclear Information System (INIS)

    Themner, Klas.

    1989-01-01

    The analytical techniques of paticle induced X-ray emission (PIXE) and Rutherford backscattering (RBS), together with the nuclear microprobe, form a very powerful tool for performing quantitative microanalysis of biological material. Calibration of the X-ray detection system in the microprobe set-up has been performed and the accuracy of the quantitative procedure using RBS for determination of the areal mass density was investigated. The accuracy of the analysis can be affected by alteration in the elemental concentrations during irradiation due to the radiation damage induced by the very intense beams of ionixing radiation. Loss of matrix elements from freeze-dried tissue sections and polymer films have been studied during proton and photon irradiation and the effect on the accuracy discussed. Scanning the beam over an area of the target, with e.g. 32x32 pixels, in order to produce en elemental map, yields a lot of information and, to be able to make an accurate quantitatification, a fast algorithm using descriptions of the different spectral contributions is of need. The production of continuum X-rays by 2.55 MeV protons has been studied and absolute cross-sections for the bremsstrahlung production from thin carbon and some polymer films determined. For the determination of the bremsstrahlung background knowledge of the amounts of the matrix elements is important and a fast program for the evaluation of spectra of proton back- and forward scattering from biological samples has been developed. Quantitative microanalysis with the nuclear microprobe has been performed on brain tissue from rats subjected to different pathological conditions. Increase in calcium levels and decrease in potssium levels for animals subjected to crebral ischaemia and for animals suffering from epileptic seizures were observed coincidentally with or, in some cases before, visible signs of cell necrosis. (author)

  3. The Radiation Source ELBE and its Research Program in Nuclear Physics

    International Nuclear Information System (INIS)

    Lehnert, U.; Michel, P.; Schwengner, R.

    2005-01-01

    The new radiation source 'Strahlungsquelle ELBE' at the Forschungszentrum Rossendorf (FZR) near Dresden, Germany, is a user facility that utilizes a superconducting linear accelerator to produce various secondary beams for experiments in nuclear science, solid state physics, materials research, environmental chemistry and in the life sciences. The high brilliance electron beam of up to 40 MeV and 1 mA (cw) is mainly used to drive free electron lasers producing infrared light in the 5-150 μm wavelength region. Additionally, polarized MeV-Bremsstrahlung and X-rays from electron channeling are available, facilities for neutron and positron production are under construction. The talk outlines the ongoing research activities at ELBE with special attention to the nuclear resonance fluorescence experiments

  4. Improved quantitative 90 Y bremsstrahlung SPECT/CT reconstruction with Monte Carlo scatter modeling.

    Science.gov (United States)

    Dewaraja, Yuni K; Chun, Se Young; Srinivasa, Ravi N; Kaza, Ravi K; Cuneo, Kyle C; Majdalany, Bill S; Novelli, Paula M; Ljungberg, Michael; Fessler, Jeffrey A

    2017-12-01

    In 90 Y microsphere radioembolization (RE), accurate post-therapy imaging-based dosimetry is important for establishing absorbed dose versus outcome relationships for developing future treatment planning strategies. Additionally, accurately assessing microsphere distributions is important because of concerns for unexpected activity deposition outside the liver. Quantitative 90 Y imaging by either SPECT or PET is challenging. In 90 Y SPECT model based methods are necessary for scatter correction because energy window-based methods are not feasible with the continuous bremsstrahlung energy spectrum. The objective of this work was to implement and evaluate a scatter estimation method for accurate 90 Y bremsstrahlung SPECT/CT imaging. Since a fully Monte Carlo (MC) approach to 90 Y SPECT reconstruction is computationally very demanding, in the present study the scatter estimate generated by a MC simulator was combined with an analytical projector in the 3D OS-EM reconstruction model. A single window (105 to 195-keV) was used for both the acquisition and the projector modeling. A liver/lung torso phantom with intrahepatic lesions and low-uptake extrahepatic objects was imaged to evaluate SPECT/CT reconstruction without and with scatter correction. Clinical application was demonstrated by applying the reconstruction approach to five patients treated with RE to determine lesion and normal liver activity concentrations using a (liver) relative calibration. There was convergence of the scatter estimate after just two updates, greatly reducing computational requirements. In the phantom study, compared with reconstruction without scatter correction, with MC scatter modeling there was substantial improvement in activity recovery in intrahepatic lesions (from > 55% to > 86%), normal liver (from 113% to 104%), and lungs (from 227% to 104%) with only a small degradation in noise (13% vs. 17%). Similarly, with scatter modeling contrast improved substantially both visually and in

  5. A Single Bremsstrahlung Monitor to Measure Luminosity at LEP

    CERN Multimedia

    2002-01-01

    The luminosity, the beam divergence and the longitudinal polarization can be measured at an interaction point of LEP by dectecting the energy, the angular distribution and the circular polarization of the single bremsstrahlung photons (SB) emitted at very forward angle. The luminosity can be measured by this met than by the conventional method of detecting small angle Bhabha scattering. The bunch to bunch relative luminosity can be monitored at a few per mil level in few minutes. Absolute values of the luminosity and of the polarization can be measured with a precision of the order of 1\\%. \\\\ \\\\ The apparatus to detect SB photons consists of a low Z absorber and of an EM calorimeter made of lead and scintillating fibres. Both the total energy and the space distribution of the SB photons are measured. This apparatus has been designed and built at the Department of Physics and INFN Section of the University of Rome ``La Sapienza''. Later on, together with suitable monocrystal converters, it may be used also for...

  6. Pions and neutrinos as probes of the nucleon and nuclear few-body system

    International Nuclear Information System (INIS)

    Hoffman, C.M.

    1993-01-01

    A number of studies of few-body nucleon and nuclear systems are being pursued at LAMPF using pions and neutrinos as probes. These include: a high-statistics measurement of the cross section for the reaction π + p → π + π o π 0 to determine the 1 = 2 ππ scattering length; precision measurements of the π - p charge exchange cross section in the region of the A; measurements of the cross section for the (π + p → π + π + p), from D, 3 He as 4 He as tests of charge symmetry and reaction mechanisms; measurements of the π + p cross section below the Δ; and studies of vp elastic scattering at low Q 2 to determine the quark content of the proton spin. Some of these experiments acquired data last year, while others are presently running. LAMPF, the highest power proton accelerator in the world, is presently in the midst of its 1993 production run

  7. Development of thermal scanning probe microscopy for the determination of thin films thermal conductivity: application to ceramic materials for nuclear industry

    International Nuclear Information System (INIS)

    David, L.

    2006-10-01

    Since the 1980's, various thermal metrologies have been developed to understand and characterize the phenomena of transport of thermal energy at microscopic and submicroscopic scales. Thermal Scanning Probe Microscopy (SThM) is promising. Based on the analysis of the thermal interaction between an heated probe and a sample, it permits to probe the matter at the level of micrometric size in volumes. Performed in the framework of the development of this technique, this work more particularly relates to the study of thin films thermal conductivity. We propose a new modelling of the prediction of measurement with SThM. This model allows not only the calibration of the method for the measurement of bulk material thermal conductivity but also to specify and to better describe the probe - sample thermal coupling and to estimate, from its inversion, thin films thermal conductivity. This new approach of measurement has allowed the determination of the thermal conductivity of micrometric and sub-micrometric thicknesses of meso-porous silicon thin film in particular. Our estimates for the micrometric thicknesses are in agreement with those obtained by the use of Raman spectrometry. For the lower thicknesses of film, we give new data. Our model has, moreover, allowed a better definition of the in-depth resolution of the apparatus. This one is strongly linked to the sensitivity of SThM and strongly depends on the probe-sample thermal coupling area and on the geometry of the probe used. We also developed the technique by the vacuum setting of SThM. Our first results under this environment of measurement are encouraging and validate the description of the coupling used in our model. Our method was applied to the study of ceramics (SiC, TiN, TiC and ZrC) under consideration in the composition of future nuclear fuels. Because of the limitations of SThM in terms of sensitivity to thermal conductivity and in-depth resolution, measurements were also undertaken with a modulated thermo

  8. Nuclear theory progress report

    International Nuclear Information System (INIS)

    1991-01-01

    This report discusses research performed at University of Washington in nuclear theory. Some of the topics discussed are: nuclear astrophysics; symmetry; time reversal invariance; quark matter; superallowed beta decay; exclusive reactions; nuclear probes; soliton model; relativistic heavy ion collisions; supernova explosions; neutrino processes in dense matter; field theories; weak interaction physics; and nuclear structure

  9. Influence of the electron cyclotron resonance plasma confinement on reducing the bremsstrahlung production of an electron cyclotron resonance ion source with metal-dielectric structures

    International Nuclear Information System (INIS)

    Schachter, L.; Dobrescu, S.; Stiebing, K. E.

    2009-01-01

    The influence of metal-dielectric (MD) layers (MD structures) inserted into the plasma chamber of an electron cyclotron resonance ion source (ECRIS) onto the production of electron bremsstrahlung radiation has been studied in a series of dedicated experiments at the 14 GHz ECRIS of the Institut fuer Kernphysik der Universitaet Frankfurt. The IKF-ECRIS was equipped with a MD liner, covering the inner walls of the plasma chamber, and a MD electrode, covering the plasma-facing side of the extraction electrode. On the basis of similar extracted currents of highly charged ions, significantly reduced yields of bremsstrahlung radiation for the 'MD source' as compared to the standard (stainless steel) source have been measured and can be explained by the significantly better plasma confinement in a MD source as compared to an ''all stainless steel'' ECRIS.

  10. Gamma-Ray Imaging Probes.

    Science.gov (United States)

    Wild, Walter James

    1988-12-01

    External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work. The central concept lies in the representation of the aperture shell by a sequence of binary digits. This, coupled with the mode of operation which is data encoding within an axial slice of space, leads to the fundamental imaging equation in which the coding operation is conveniently described by a circulant matrix operator. The coding/decoding process is a classic coded-aperture problem, and various estimators to achieve decoding are discussed. Some estimators require a priori information about the object (or object class) being imaged; the only unbiased estimator that does not impose this requirement is the simple inverse-matrix operator. The effects of noise on the estimate (or reconstruction) is discussed for general noise models and various codes/decoding operators. The choice of an optimal aperture for detector count times of clinical relevance is examined using a statistical class-separability formalism.

  11. Evaluation of quantitative planar 90Y bremsstrahlung whole-body imaging

    International Nuclear Information System (INIS)

    Minarik, D; Ljungberg, M; Gleisner, K Sjoegreen; Segars, P

    2009-01-01

    With high-dose administration of 90 Y labeled antibodies, it is possible to image 90 Y without an admixture of 111 In. We have earlier shown that it is possible to perform quantitative 90 Y bremsstrahlung SPECT for dosimetry purposes with reasonable accuracy. However, whole-body (WB) activity quantification with the conjugate view method is not as time consuming as SPECT and has been the method of choice for dosimetry. We have investigated the possibility of using a conjugate view method where scatter-, backscatter- and septal-penetration compensations are performed by inverse filtering and attenuation correction is performed with a WB x-ray image, for total-body and organ activity quantification of 90 Y. The method was evaluated using both Monte Carlo simulated scintillation camera images using realistic source distributions, and by an experimental phantom study. The method was evaluated in terms of image quality and accuracy of the activity quantification. The experimental phantom study was performed using the RSD torso phantom with 90 Y activity uniformly distributed in the liver insert. A GE Discovery VH/Hawkeye system was used to acquire the image. The simulation study was performed for a realistic activity distribution in the NCAT anthropomorphic phantom where 90 Y bremsstrahlung images were generated using the SIMIND MC program. Two different phantom configurations and two activity distributions were simulated. To mimic the RSD phantom experiment one simulation study was also made with 90 Y activity located only in the liver. The SIMIND program was configured to resemble a GE Discovery VH/Hawkeye system. An x-ray projector program was used to generate whole-body x-ray images from the NCAT phantom for attenuation correction in the conjugate view method. Organ activities were calculated from ROIs that exactly covered the organs. Corrections for background activity, overlapping activity and source extension in the depth direction were applied on the ROI data

  12. Probing for heavy element impurities in the shell of the Pacific oyster, Crassostrea gigas, with nuclear microscopy

    International Nuclear Information System (INIS)

    Markwitz, A.; Barry, B.; Gauldie, R.W.; Roberts, R.D.

    2003-01-01

    Nuclear microscopy was performed on shells of the Pacific oyster, Crassostrea gigas, to probe for heavy element impurities. For the studies 14 shells from the Auckland and the Marlborough Sounds region were chosen. In sections, the shells appear as opaque with white and grey zones, which are related to alternating layers of calcite and aragonite. Raster scans with 2.5 MeV protons over the sections (scan area 5 x 5 mm) were used in the experiment to measure trace elements in the ppm region using proton induced X-ray spectroscopy. Two dimensional maps and line scans revealed the presence of bromine in all shells investigated. Bromine was found to be related with the pattern of calcium. Hot spots of iron proved to be a common feature in the shells as well. In some shells, copper and zinc were also measured in hot spots of a few micrometers in diameter. Spatially resolved results on the micrometer level indicate the usefulness of nuclear microscopy for the detection of heavy elements in shells of the Pacific oyster

  13. Tomography of the fast electron Bremsstrahlung emission during lower hybrid current drive on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y.; Imbeaux, F. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France)

    1999-04-01

    A new tomography dedicated to detailed studies of the fast electron Bremsstrahlung emission in the hard X-ray (HXR) energy range between 20 and 200 keV during lower hybrid (LH) current drive experiments on the TORE SUPRA tokamak [Equipe TORE SUPRA, in Proceedings of the 15. Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville (International Atomic Energy Agency, Vienna, 1995), 1, AIEA-CN-60 / A1-5, p. 105] is presented. Radiation detection is performed by cadmium telluride(CdTe) semiconductors, which have most of the desirable features for a powerful diagnosing of magnetically confined hot plasmas - compact size, high X-ray stopping efficiency, fast timing characteristics, good energy resolution, no sensitivity to magnetic field, reasonable susceptibility to performance degradation from neutron/{gamma}-induced damages. This instrument is made of two independent cameras viewing a poloidal cross-section of the plasma, with respectively 21 and 38 detectors. A coarse spectrometry - 8 energy channels - is carried out for each chord, with an energy resolution of 20 keV. The spatial resolution in the core of the plasma is 4-5 cm, while the time sampling may be lowered down to of 2-4 ms. Powerful inversion techniques based on maximum entropy or regularization algorithms take fully advantage of the large number of line-integrated measurements for very robust estimates of the local HXR profiles as a function of time and photon energy. A detailed account of main characteristics and performances of the diagnostic is reported as well as preliminary results on LH current drive experiments. (authors)

  14. Tomography of the fast electron Bremsstrahlung emission during lower hybrid current drive on Tore Supra

    International Nuclear Information System (INIS)

    Peysson, Y.; Imbeaux, F.

    1999-04-01

    A new tomography dedicated to detailed studies of the fast electron Bremsstrahlung emission in the hard X-ray (HXR) energy range between 20 and 200 keV during lower hybrid (LH) current drive experiments on the TORE SUPRA tokamak [Equipe TORE SUPRA, in Proceedings of the 15. Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville (International Atomic Energy Agency, Vienna, 1995), 1, AIEA-CN-60 / A1-5, p. 105] is presented. Radiation detection is performed by cadmium telluride (CdTe) semiconductors, which have most of the desirable features for a powerful diagnosing of magnetically confined hot plasmas - compact size, high X-ray stopping efficiency, fast timing characteristics, good energy resolution, no sensitivity to magnetic field, reasonable susceptibility to performance degradation from neutron/γ-induced damages. This instrument is made of two independent cameras viewing a poloidal cross-section of the plasma, with respectively 21 and 38 detectors. A coarse spectrometry - 8 energy channels - is carried out for each chord, with an energy resolution of 20 keV. The spatial resolution in the core of the plasma is 4-5 cm, while the time sampling may be lowered down to of 2-4 ms. Powerful inversion techniques based on maximum entropy or regularization algorithms take fully advantage of the large number of line-integrated measurements for very robust estimates of the local HXR profiles as a function of time and photon energy. A detailed account of main characteristics and performances of the diagnostic is reported as well as preliminary results on LH current drive experiments. (authors)

  15. Practical reconstruction protocol for quantitative {sup 90}Y bremsstrahlung SPECT/CT

    Energy Technology Data Exchange (ETDEWEB)

    Siman, W.; Mikell, J. K.; Kappadath, S. C., E-mail: skappadath@mdanderson.org [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030 (United States)

    2016-09-15

    Purpose: To develop a practical background compensation (BC) technique to improve quantitative {sup 90}Y-bremsstrahlung single-photon emission computed tomography (SPECT)/computed tomography (CT) using a commercially available imaging system. Methods: All images were acquired using medium-energy collimation in six energy windows (EWs), ranging from 70 to 410 keV. The EWs were determined based on the signal-to-background ratio in planar images of an acrylic phantom of different thicknesses (2–16 cm) positioned below a {sup 90}Y source and set at different distances (15–35 cm) from a gamma camera. The authors adapted the widely used EW-based scatter-correction technique by modeling the BC as scaled images. The BC EW was determined empirically in SPECT/CT studies using an IEC phantom based on the sphere activity recovery and residual activity in the cold lung insert. The scaling factor was calculated from 20 clinical planar {sup 90}Y images. Reconstruction parameters were optimized in the same SPECT images for improved image quantification and contrast. A count-to-activity calibration factor was calculated from 30 clinical {sup 90}Y images. Results: The authors found that the most appropriate imaging EW range was 90–125 keV. BC was modeled as 0.53× images in the EW of 310–410 keV. The background-compensated clinical images had higher image contrast than uncompensated images. The maximum deviation of their SPECT calibration in clinical studies was lowest (<10%) for SPECT with attenuation correction (AC) and SPECT with AC + BC. Using the proposed SPECT-with-AC + BC reconstruction protocol, the authors found that the recovery coefficient of a 37-mm sphere (in a 10-mm volume of interest) increased from 39% to 90% and that the residual activity in the lung insert decreased from 44% to 14% over that of SPECT images with AC alone. Conclusions: The proposed EW-based BC model was developed for {sup 90}Y bremsstrahlung imaging. SPECT with AC + BC gave improved lesion

  16. Bremsstrahlung spectra from thick-target electron beams with noncollisional energy losses

    International Nuclear Information System (INIS)

    Brown, J.C.; MacKinnon, A.L.

    1985-01-01

    We consider what can be learned from the bremsstrahlung radiation of fast electrons in a thick target, generalized to include electron energy losses additional to collisions. We show that the observed photon spectrum can, in principle, be inverted to yield an integral functional of the electron spectrum and the effective energy loss rate. In the light of this result, there seems no reason to suppose, in the absence of a priori information to the contrary, that the photon spectrum is symptomatic more of the fast electron distribution than of the energy loss processes. In cases where the electron injection spectrum is known on independent observational or theoretical grounds, it is possible to infer an effective, ''phenomenological'' energy loss function. In the more general case, however, fullest possible modeling of the physical situation and comparison of the resulting spectrum with observations is all that can be attempted

  17. Nuclear magnetic resonance probe head design for precision strain control

    International Nuclear Information System (INIS)

    Kissikov, T.; Sarkar, R.; Bush, B. T.; Lawson, M.; Canfield, P. C.; Curro, N. J.

    2017-01-01

    Here, we present the design and construction of an NMR probe to investigate single crystals under strain at cryogenic temperatures. The probe head incorporates a piezoelectric-based apparatus from Razorbill Instruments that enables both compressive and tensile strain tuning up to strain values on the order of 0.3% with a precision of 0.001%. 75 As NMR in BaFe 2 As 2 reveals large changes to the electric field gradient and indicates that the strain is homogeneous to within 16% over the volume of the NMR coil.

  18. Influence of the electron cyclotron resonance plasma confinement on reducing the bremsstrahlung production of an electron cyclotron resonance ion source with metal-dielectric structures.

    Science.gov (United States)

    Schachter, L; Stiebing, K E; Dobrescu, S

    2009-01-01

    The influence of metal-dielectric (MD) layers (MD structures) inserted into the plasma chamber of an electron cyclotron resonance ion source (ECRIS) onto the production of electron bremsstrahlung radiation has been studied in a series of dedicated experiments at the 14 GHz ECRIS of the Institut für Kernphysik der Universität Frankfurt. The IKF-ECRIS was equipped with a MD liner, covering the inner walls of the plasma chamber, and a MD electrode, covering the plasma-facing side of the extraction electrode. On the basis of similar extracted currents of highly charged ions, significantly reduced yields of bremsstrahlung radiation for the "MD source" as compared to the standard (stainless steel) source have been measured and can be explained by the significantly better plasma confinement in a MD source as compared to an "all stainless steel" ECRIS.

  19. Using of germanium detectors in nuclear experiments with photon beams

    International Nuclear Information System (INIS)

    Kapitonov, I.M.; Tutin, I.A.

    1995-01-01

    Full text: The study of atomic nuclei with real photons is very important source of the information about nuclear structure. In such experiments the basic electromagnetic interaction between the photon and the target nuclei is well known. Experiments with photon beams become especially valuable when outcoming particles are also photons. In these cases completely model-independent information on nuclear structure can be extracted. The use of semiconductor Ge-spectrometers with excellent resolution and large sensitive volumes for recording outcoming photons gives us such an additional important advantage as possibility to observe individual closely spaced levels of the final nuclei. In the report an experience of using Ge-detectors in two types of nuclear experiments is described. Both of them - nuclear resonance fluorescence (NRF) and nuclear photodisintegration - are carried out in beams of bremsstrahlung gamma radiation. The central element of the setup recording gamma quanta in these experiments is germanium detector. NRF is unique method for studying low-lying excited nuclear states. The spins of the states can be determined easily from the measured angular distributions of scattered photons. Model independent parity assignments in NRF can be achieved by measuring polarization observables. There are two experimental possibilities: the use of linearly polarized photons (off-axis bremsstrahlung) in the entrance channel and the measurement of the linear polarization of the scattered photons using Compton polarimeters. For both methods several germanium detectors (3-5) must be used simultaneously. Nowadays Compton polarimeter can also be done from single large Ge-crystal by segmenting the outer electrode. Advantages and drawbacks of the methods and background conditions are discussed and requirements to Ge-crystals are formulated. The importance of using a new generation of electron accelerators with continuous wave (cw) beams for NRF-measurements is stressed. The

  20. Cultivation of nuclear safety culture in Guangdong Nuclear Power Station (GNPS)

    International Nuclear Information System (INIS)

    Lu Wei; Tang Yanzhao

    2004-01-01

    Probed into the concept and developing phases of safety couture in the management of nuclear power station, especially analyzed the background and the road of cultivating nuclear safety culture in GNPS, highlighted the core concept of GNPS nuclear safety culture, presented GNPS safety culture indicators, summarized the major measures taken by GNPS, depicted the propagandizing process of transparency in GNPS, and systematically appraised the effect of GNPS in implementing nuclear safety culture. (authors)

  1. Calculation of gas Bremsstrahlung power from straight sections of storage ring at SSRF

    International Nuclear Information System (INIS)

    Hua Zhengdong; Xu Xunjiang; Fang Keming; Xu Jiaqiang

    2008-01-01

    The Shanghai Synchrotron Radiation Facility (SSRF) is a third-generation synchrotron radiation light source with 3.5 GeV in energy, which is composed of the linear accelerator, the booster and the storage ring. The storage ring provides 16 standard straight sections of 6.5 m and 4 long straight sections of 12 meters. Gas Bremsstrahlung (GB) produced by the interaction of the stored beam with the residual gas molecules in straight section, which is so intense and has a very small angular that the GB spectra, the GB power and the GB power distribution should be known. The characters of GB are studied by means of Fluka Monte Carlo code. Our result shows agreement with those obtained by the experiential formulae. (authors)

  2. Traversing incore probe device

    International Nuclear Information System (INIS)

    Yoshioka, Michiko.

    1985-01-01

    Purpose: To measure the neutron flux distribution in the reactor core always at a high accuracy. Constitution: A nuclear fission ionizing chamber type detector is disposed at the end of a cable for sending a detection signal of a traversing incore probe device and, further, a gamma-ray ionizing chamber type detector is connected in adjacent therewith and a selection circuit for selecting both of the detection signals and inputting them to a display device is disposed. Then, compensation for the neutron monitors is conducted by the gamma-ray ionizing chamber type detector during normal operation in which control rods are not driven and the positioning is carried out by the nuclear fission ionizing chamber type detector. Furthermore, both of the compensation for the neutron detector and the positioning are carried out by the nuclear fission ionizing chamber type detector upon starting where the control rods are driven. (Sekiya, K.)

  3. Laser-assisted collisions: The Kroll-Watson formula and bremsstrahlung theory

    International Nuclear Information System (INIS)

    Geltman, S.

    1996-01-01

    Recent measurements on CO 2 -laser-assisted electron-atom collisions have shown large inconsistencies with the Kroll-Watson formula for small-angle scattering. We have carried out a detailed study to compare the predictions of Kroll-Watson theory (for both single and multimode fields) with those of conventional perturbation theory for stimulated free-free transitions. It is found that for E 0 /2ω 2 <1, where perturbation theory is valid, there are large differences with the Kroll-Watson theory. Comparisons of experimental variations with respect to scattering angle and electron energy show much better agreement with perturbation theory than with Kroll-Watson theory. A study of the angular variations in perturbation theory shows that use of the open-quote open-quote outgoing close-quote close-quote wave final state gives much better agreement with experiment than does the open-quote open-quote ingoing close-quote close-quote wave final state, which is different from the choice made in early bremsstrahlung theory. copyright 1996 The American Physical Society

  4. Investigation of ferromagnetic spinel semiconductors by hyperfine interactions of implanted nuclear probes

    CERN Document Server

    Samokhvalov, V; Dietrich, M; Schneider, F; Tiginyanu, I M; Tsurkan, V; Unterricker, S

    2003-01-01

    The semiconducting ferromagnetic spinel compounds CdCr//2Se //4, CdCr //2S//4, HgCr//2Se//4 and CuCr//2Se//4 (metallic) were investigated by the perturbed angular correlations (PAC) method with the radioactive probes **1**1**1In, **1**1**1**mCd, **1**1**1Ag, **1**1**7Cd, **1**9**9**mHg and **7**7Br. The probes were implanted at the ISOLDE on-line separator (CERN-Geneva) into single crystals. From the time dependence of the PAC spectra and the measured hyperfine interaction parameters: electric field gradient and magnetic hyperfine field, the probe positions and the thermal behavior of the probes could be determined. Cd, Ag and Hg are substituted at the A-site, In at the A- and B-site in the semiconducting compounds and Br at the anion position. Electric and magnetic hyperfine fields were used as test quantities for theoretical charge and spin density distributions of LAPW calculations (WIEN97).

  5. Portal monitor incorporating smart probes

    International Nuclear Information System (INIS)

    Bartos, D.; Constantin, F.; Guta, T.

    2003-01-01

    Portal monitors are intended for detection of radioactive and special nuclear materials in vehicles, pedestrians, luggage, as well as for prevention of illegal traffic of radioactive sources. Monitors provide audio and visual alarms when radioactive and/or special nuclear materials are detected. They can be recommended to officers of customs, border guard and emergency services, civil defense, fire brigades, police and military departments or nuclear research or energetic facilities. The portal monitor developed by us consists in a portal frame, which sustains five intelligent probes having long plastic scintillator (0.5 liters each). The probes communicate, by serial transmission, with a Central Unit constructed on the basis of the 80552 microcontroller. This one manages the handshake, calculates the background, establishes the measuring time, starts and stops each measurement and makes all the other decisions. Sound signals and an infrared sensor monitor the passing through the portal and the measuring procedure. For each measurement the result is displayed on a LCD device contaminated/uncontaminated; for the contaminated case a loud and long sound signal is also issued. An RS 232 serial interface is provided in order to further developments or custom made devices. As a result, the portal monitor detects 1 μ Ci 137 Cs, spread all over a human body, in a 20 μR/h gamma background for a measuring time of 1.5 or 10 seconds giving a 99% confidence factor. (authors)

  6. Progress report of the nuclear physics department

    International Nuclear Information System (INIS)

    1988-01-01

    This progress report presents the research programs and the technical developments carried out at the Nuclear Physics Department of Saclay from October 1, 1986 to September 30, 1987. The research programs concern the structure of nuclei and the general study of nuclear reaction mechanisms. Experiments use electromagnetic probes of the 700 Mev Saclay linear electron accelerator and hadronic probes, light polarised particles and heavy ions of the National Laboratories SATURNE and GANIL. The Nuclear Physics Department is also involved in development of accelerator technologies, especially in the field of superconducting cavities [fr

  7. Single point aerosol sampling: Evaluation of mixing and probe performance in a nuclear stack

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, J.C.; Fairchild, C.I.; Wood, G.O. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-02-01

    Alternative Reference Methodologies (ARMs) have been developed for sampling of radionuclides from stacks and ducts that differ from the methods required by the U.S. EPA. The EPA methods are prescriptive in selection of sampling locations and in design of sampling probes whereas the alternative methods are performance driven. Tests were conducted in a stack at Los Alamos National Laboratory to demonstrate the efficacy of the ARMs. Coefficients of variation of the velocity tracer gas, and aerosol particle profiles were determined at three sampling locations. Results showed numerical criteria placed upon the coefficients of variation by the ARMs were met at sampling stations located 9 and 14 stack diameters from flow entrance, but not at a location that is 1.5 diameters downstream from the inlet. Experiments were conducted to characterize the transmission of 10 {mu}m aerodynamic equivalent diameter liquid aerosol particles through three types of sampling probes. The transmission ratio (ratio of aerosol concentration at the probe exit plane to the concentration in the free stream) was 107% for a 113 L/min (4-cfm) anisokinetic shrouded probe, but only 20% for an isokinetic probe that follows the EPA requirements. A specially designed isokinetic probe showed a transmission ratio of 63%. The shrouded probe performance would conform to the ARM criteria; however, the isokinetic probes would not.

  8. Magnetic Probe Construction using Thick-film Technology

    International Nuclear Information System (INIS)

    Takahashi, H.; Sakakibara, S.; Kubota, Y.; Yamada, H.

    2001-01-01

    Thick-film technology has been successfully adapted for the design and fabrication of magnetic probes of a new type suitable for use in the simultaneous ultra-high vacuum and high-temperature environment of a nuclear fusion device. The maximum usable temperature is expected to be around 900 degrees C. This new probe has a specific sensitivity (coupling area per unit volume) an order of magnitude higher than a conventional coil. The new probe in one implementation is capable of simultaneously measuring magnetic field in three orthogonal directions about a single spatial point and in two frequency ranges. Low-frequency coils have a measured coupling area of 296-323 cm squared and a frequency response of about 300 kHz. High-frequency coils have a design coupling area of 12-15 cm squared

  9. Nuclear Deformation and Neutron Excess as Competing Effects for Dipole Strength in the Pygmy Region

    Science.gov (United States)

    Massarczyk, R.; Schwengner, R.; Dönau, F.; Frauendorf, S.; Anders, M.; Bemmerer, D.; Beyer, R.; Bhatia, C.; Birgersson, E.; Butterling, M.; Elekes, Z.; Ferrari, A.; Gooden, M. E.; Hannaske, R.; Junghans, A. R.; Kempe, M.; Kelley, J. H.; Kögler, T.; Matic, A.; Menzel, M. L.; Müller, S.; Reinhardt, T. P.; Röder, M.; Rusev, G.; Schilling, K. D.; Schmidt, K.; Schramm, G.; Tonchev, A. P.; Tornow, W.; Wagner, A.

    2014-02-01

    The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A =124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the γELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIγS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of molybdenum isotopes and with predictions of a random-phase approximation in a deformed basis. It turned out that the effect of nuclear deformation plays a minor role compared with the one caused by neutron excess. A global parametrization of the strength in terms of neutron and proton numbers allowed us to derive a formula capable of predicting the summed E1 strengths in the pygmy region for a wide mass range of nuclides.

  10. Nuclear deformation and neutron excess as competing effects for dipole strength in the pygmy region.

    Science.gov (United States)

    Massarczyk, R; Schwengner, R; Dönau, F; Frauendorf, S; Anders, M; Bemmerer, D; Beyer, R; Bhatia, C; Birgersson, E; Butterling, M; Elekes, Z; Ferrari, A; Gooden, M E; Hannaske, R; Junghans, A R; Kempe, M; Kelley, J H; Kögler, T; Matic, A; Menzel, M L; Müller, S; Reinhardt, T P; Röder, M; Rusev, G; Schilling, K D; Schmidt, K; Schramm, G; Tonchev, A P; Tornow, W; Wagner, A

    2014-02-21

    The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A=124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the γELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIγS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of molybdenum isotopes and with predictions of a random-phase approximation in a deformed basis. It turned out that the effect of nuclear deformation plays a minor role compared with the one caused by neutron excess. A global parametrization of the strength in terms of neutron and proton numbers allowed us to derive a formula capable of predicting the summed E1 strengths in the pygmy region for a wide mass range of nuclides.

  11. Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages.

    Science.gov (United States)

    Jones, Christopher P; Brenner, Ceri M; Stitt, Camilla A; Armstrong, Chris; Rusby, Dean R; Mirfayzi, Seyed R; Wilson, Lucy A; Alejo, Aarón; Ahmed, Hamad; Allott, Ric; Butler, Nicholas M H; Clarke, Robert J; Haddock, David; Hernandez-Gomez, Cristina; Higginson, Adam; Murphy, Christopher; Notley, Margaret; Paraskevoulakos, Charilaos; Jowsey, John; McKenna, Paul; Neely, David; Kar, Satya; Scott, Thomas B

    2016-11-15

    A small scale sample nuclear waste package, consisting of a 28mm diameter uranium penny encased in grout, was imaged by absorption contrast radiography using a single pulse exposure from an X-ray source driven by a high-power laser. The Vulcan laser was used to deliver a focused pulse of photons to a tantalum foil, in order to generate a bright burst of highly penetrating X-rays (with energy >500keV), with a source size of <0.5mm. BAS-TR and BAS-SR image plates were used for image capture, alongside a newly developed Thalium doped Caesium Iodide scintillator-based detector coupled to CCD chips. The uranium penny was clearly resolved to sub-mm accuracy over a 30cm(2) scan area from a single shot acquisition. In addition, neutron generation was demonstrated in situ with the X-ray beam, with a single shot, thus demonstrating the potential for multi-modal criticality testing of waste materials. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material. With recent developments of high-power laser systems, to 10Hz operation, a laser-driven multi-modal beamline for waste monitoring applications is envisioned. Copyright © 2016. Published by Elsevier B.V.

  12. Time-resolved electron thermal conduction by probing of plasma formation in transparent solids with high power subpicosecond laser pulses

    International Nuclear Information System (INIS)

    Vu, B.T.V.

    1994-02-01

    This dissertation work includes a series of experimental measurements in a search for better understanding of high temperature (10 4 -10 6 K) and high density plasmas (10 22 -10 24 cm -3 ) produced by irradiating a transparent solid target with high intensity (10 13 - 10 15 W/cm 2 ) and subpicosecond (10 -12 -10 -13 s) laser pulses. Experimentally, pump and probe schemes with both frontside (vacuum-plasma side) and backside (plasma-bulk material side) probes are used to excite and interrogate or probe the plasma evolution, thereby providing useful insights into the plasma formation mechanisms. A series of different experiments has been carried out so as to characterize plasma parameters and the importance of various nonlinear processes. Experimental evidence shows that electron thermal conduction is supersonic in a time scale of the first picosecond after laser irradiation, so fast that it was often left unresolved in the past. The experimental results from frontside probing demonstrate that upon irradiation with a strong (pump) laser pulse, a thin high temperature (∼40eV) super-critical density (∼10 23 /cm 3 ) plasma layer is quickly formed at the target surface which in turn becomes strongly reflective and prevents further transmission of the remainder of the laser pulse. In the bulk region behind the surface, it is also found that a large sub-critical (∼10 18 /cm 3 ) plasma is produced by inverse Bremsstrahlung absorption and collisional ionization. The bulk underdense plasma is evidenced by large absorption of the backside probe light. A simple and analytical model, modified from the avalanche model, for plasma evolution in transparent materials is proposed to explain the experimental results. Elimination of the bulk plasma is then experimentally illustrated by using targets overcoated with highly absorptive films

  13. Rare gas isotope yields in bremsstrahlung-induced nuclear reactions of 41K, 87Rb, 127I, 133Cs, and 139La

    International Nuclear Information System (INIS)

    Oura, Y.; Yazawa, A.; Sarkar, S.R.; Sakamoto, K.; Shibata, S.; Fujiwara, I.; Furukawa, M.

    1994-05-01

    Radiochemical yield measurements have been reported for 41 K(γ, π + ) 41 Ar, 87 Rb(γ, π + ) 87 Kr, 133 Cs(γ, π + ) 133m,133g Xe, 127 I(γ, π - xn) 127-x Xe (x=0,2,4,5, and 6), 133 Cs(γ, pxn) 132-x Xe (x=1,3,5,7,9,10, and 11), and 139 La(γ, 3pxn) 136- xXe (x=7,9,11,13,14, and 15) at bremsstrahlung end-point energies(E 0 ) of 50-1200 MeV. For photopion reactions it has been confirmed that the both yields of (γ, π - ) and (γ, π + ) reactions are independent of target mass (A t ) and the yield ratios of (γ, π - ) to (γ, π + ) reactions are about 5 over the studied ranges of E 0 and A t . The profile of 127 I(γ, π - xn) yields as a function of x is similar to that of 133 Cs but quite different from that of 51 V when compared at the same E 0 , suggesting a strong A t dependence. It is also found that the photospallogenic Xe isotope yields from 133 Cs and 139 La are consistent with the reported mass yield pattems of the other radionuclides produced from the same targets. These results are discussed by referring to the previous literature values and to a cascade-evaporation calculation based on the PICA code by Gabriel and Alsmiller. (author)

  14. Inner Bremsstrahlung accompanying the non-unique first forbidden β-decay of 141Ce

    International Nuclear Information System (INIS)

    Khalil, E.I.

    1993-01-01

    The inner Bremsstrahlung (I.B.) spectrum accompanying the β-decay of 141 Ce (non-unique first forbidden β-transition) was measured using a single channel scintillation spectrometer. The measured I.B. was analyzed by the variable width peeling-off method. This analyzed and corrected I.B. was compared with those calculated according to the original theories of Knipp and Uhlenbeck as well as of Bloch (KUB), the coulomb corrected theories of Lewis and Ford and of Nilsson, and according to detour-transition calculations of the Ford and Martin theory. Ths shape correction factor suggested by Konopinski and Uhlenbeck on the Fermi β-decay theory was applied to the calculated I.B. based on Nilsson's theory (modified KUB theory). The experimental results are in better agreement with the modified KUB theory than the other theories. (orig.)

  15. Nuclear research with the electromagnetic probe. Final progress report

    Energy Technology Data Exchange (ETDEWEB)

    Meziani, Z.E.

    1994-10-01

    This is the final report on the research carried at Stanford University under contract DE-FG03-88ER40439. All the work accomplished under this grant is reported in the publications listed as part of the Principal Investigator bibliography at the end of this report. In the last few years our research was directed at some of the forefront questions in nuclear physics. We investigated the nuclear medium effects on the intrinsic properties of bound nucleons, specifically the ectromagnetic form factors. For these studies we performed a number of specialized electron scattering experiments with specific sensitivity to nuclear medium effects. At the next level of structure, elementary constituents of matter are quarks and gluons. Defining the energy regime where the quark-gluon description of nuclear systems becomes more relevant than the nucleon-meson description is of great importance in thoroughly understanding the nuclear structure. To explore this transition region, we studied the scaling region in the disintegration of the deuteron, the simplest nuclear system with high energy photons. Finally we focused on the investigation of the nucleon internal spin structure along with the test of the Bjoerken sum rule a fundamental sum rule of QCD.

  16. Nuclear research with the electromagnetic probe. Final progress report

    International Nuclear Information System (INIS)

    Meziani, Z.E.

    1994-10-01

    This is the final report on the research carried at Stanford University under contract DE-FG03-88ER40439. All the work accomplished under this grant is reported in the publications listed as part of the Principal Investigator bibliography at the end of this report. In the last few years our research was directed at some of the forefront questions in nuclear physics. We investigated the nuclear medium effects on the intrinsic properties of bound nucleons, specifically the ectromagnetic form factors. For these studies we performed a number of specialized electron scattering experiments with specific sensitivity to nuclear medium effects. At the next level of structure, elementary constituents of matter are quarks and gluons. Defining the energy regime where the quark-gluon description of nuclear systems becomes more relevant than the nucleon-meson description is of great importance in thoroughly understanding the nuclear structure. To explore this transition region, we studied the scaling region in the disintegration of the deuteron, the simplest nuclear system with high energy photons. Finally we focused on the investigation of the nucleon internal spin structure along with the test of the Bjoerken sum rule a fundamental sum rule of QCD

  17. Sterilization of health care products by 5 MeV bremsstrahlung (X ray)

    International Nuclear Information System (INIS)

    Sato, Yoshishige; Takahashi, Thoru; Saito, Toshio; Sato, Toshio; Takehisa, Masaaki

    1993-01-01

    Radiation sensitivities of B. pumilis and B. subtilis spores were examined to bremsstrahlung of 5 MeV EB and Cobalt-60 γ rays in order to confirm the effects of radiation and dose rate. Biological indicators were irradiated with the X rays in the dose rate range of 4.7-47 kGy/h. D-value of B. pumilis spores was 1.4-1.5 kGy, and that of B. subtilis was 1.1-1.3 kGy. The D-values of B. pumilus and B. subtilis have very small dose rate dependences to X ray, and the D-values are similar to those of γ rays. Dose distribution by X-ray and γ irradiation was measured for cartons containing 32 unit dialyzers. The D max. /D min. of the X-ray irradiation (1.2) was smaller than that of γ ray (1.3). (author)

  18. The effect of correction factors on internal bremsstrahlung spectrum

    International Nuclear Information System (INIS)

    Elias, M.M.

    1985-01-01

    Correction factors affecting the experimental spectrum of internal bremsstrahlung (IB) accompanying B-decay have been studied. A wide survey of previous experimental studies, show a discrepancy between experimental results and the available theories of IB production especially for heavy nuclides and forbidden B-transitions, with some agreement in bounded regions in IB spectrum. This is due to the uncertainity in evaluating correction factors and neglecting others. The experimental distributions of IB from 147 Pm, 204 Tl and 90 Y are measured by using two different crystals of NaI(Tl) scintillators (2''x2'' and 3'''x3'') with suitable geometrical arrangements designed to minimize the effect of several factors. The present study covers overlapped ranges of energy from 0.05 to 2.2 MeV to observe the effect of these factors along this wide region of energy. The experimental probabilities are compared with theories. It agrees fairly well with Lewis and Ford theory in case of 14 '7Pm, 204 Tl, and with detour transitions theory in the intermediate region of energies of IB spectrum from 90 Y. Deviation of our results from theories is less than all previous experimental work. 20 tabs.; 43 figs.; 84 refs.; 5 apps

  19. A 282 GHz Probe for Dynamic Nuclear Polarization

    DEFF Research Database (Denmark)

    Rybalko, Oleksandr; Bowen, Sean; Zhurbenko, Vitaliy

    Introduction In DNP, microwave irradiation of a sample facilitates the transfer of spin polarization from electrons tonuclei. One of the way to improve the DNP enhancement is to transfer microwave power from the mm-wave source tothe sample more effectively. Several methods and techniques to effic......Introduction In DNP, microwave irradiation of a sample facilitates the transfer of spin polarization from electrons tonuclei. One of the way to improve the DNP enhancement is to transfer microwave power from the mm-wave source tothe sample more effectively. Several methods and techniques......: microwave can with RF coil; the rest of the probe consists of a waveguide, sample tube and coaxial transmission line. The probe is designed to study cylindrical samples with diameter - 9 mm, and height – 2-20 mm. An RF coil which is housed in cylindrical Macor coil form (dielectric with ε=5.64 and tangent δ...... is 0.0025) surrounds the sample. The RF coil has a saddle form and was madeout of two current loops run on opposite sides of a cylinder (in parallel). Material of the coil is copper wire with diameterequal to 0.7 mm. Coil dimensions are: diameter - 13 mm; height - 22.0 mm. The self resonant frequency...

  20. Nuclear lobby group launches television ad campaign

    International Nuclear Information System (INIS)

    1992-01-01

    Nuclear power is the green wave of the future, according to a television advertising campaign launched by Canada's nuclear industry and designed to help counter the anti-nuclear messages delivered by groups such as Green peace and Energy Probe

  1. New exclusion limits for dark gauge forces from proton Bremsstrahlung in beam-dump data

    Energy Technology Data Exchange (ETDEWEB)

    Bluemlein, Johannes [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Brunner, Juergen [Aix-Marseille Univ. CNRS/IN2P3 (France). CPPM

    2013-11-15

    We re-analyze published proton beam dump data taken at the U70 accelerator at IHEP Serpukhov with the {nu}-calorimeter I experiment in 1989 to set mass-coupling limits for dark gauge forces. The corresponding data have been used for axion and light Higgs particle searches before. More recently, limits on dark gauge forces have been derived from this data set, considering a dark photon production from {pi}{sup 0}-decay. Here we determine extended mass and coupling exclusion bounds for dark gauge bosons ranging to masses m{sub {gamma}'} of 624 MeV at admixture parameters {epsilon}{approx_equal}10{sup -6} considering high-energy Bremsstrahlung of the U-boson of the initial proton beam and different detection mechanisms.

  2. PICA, Photon-Induced Medium-Range Nuclear Cascade Analysis by Monte-Carlo

    International Nuclear Information System (INIS)

    2001-01-01

    1 - Description of program or function: PIC calculates the results of nuclear reactions caused by the collision of medium-energy photons with nuclei. The photon energy range in which the calculations are applicable is 30 4 are possible. The program PIC can accommodate incident monoenergetic photons as well as thin-target Bremsstrahlung spectra, thin-target Bremsstrahlung difference spectra and thick-target Bremsstrahlung spectra. For the last type of spectra the user must furnish the photon spectral data. PIC writes a history tape containing data on the properties of the particles (protons, neutrons, or pions) escaping from the nucleus. The data consists of the types of escaping particles and their energies and angles of emission. MECCAN utilizes the data on the PIC history tape to calculate cross sections such as the nonelastic cross section or the doubly differential cross section for energy-angle correlated distributions. EVAP then carries the nuclear reaction through an additional phase, that of evaporation, and calculates the energy spectra of particles (protons, neutrons, deuterons, tritons, 3 He, and alpha particles) 'boiled off' from the nucleus after the cascade has stopped, evaporation particle multiplicities, and evaporation residual nuclei (radio-chemical) cross sections. 2 - Method of solution: The interaction of high-energy photons with nuclei is described by using the intranuclear cascade and evaporation models. Monte Carlo methods are employed to provide a detailed description of each interaction. The initial interaction of the photon with the nucleus is obtained from the quasi-deuteron model of Levinger, that is, photon absorption by a neutron-proton pair moving within the nucleus or from one of the four pion-nucleon states formed in the photon-nucleon interaction. The effect of secondary nucleon-nucleus and/or pion-nucleus interactions following the photon absorption is accounted for by utilizing the intranuclear-cascade concept of high

  3. High Momentum Probes of Nuclear Matter

    Energy Technology Data Exchange (ETDEWEB)

    Fries, R.

    2009-07-24

    We discuss how the chemical composition of QCD jets is altered by final state interactions in surrounding nuclear matter. We describe this process through conversions of leading jet particles. We find that conversions lead to an enhancement of kaons at high transverse momentum in Au+Au collisions at RHIC, while their azimuthal asymmetry v{sub 2} is suppressed.

  4. Probing the nuclear liquid-gas phase transition

    International Nuclear Information System (INIS)

    Pochodzalla, J.; Moehlenkamp, T.; Rubehn, T.; Schuettauf, A.; Zude, E.; Begemann-Blaich, M.; Blaich, T.; Emling, H.; Ferrero, A.; Kunze, W.D.; Lindenstruth, V.; Lynen, U.; Moroni, W.; Ocker, B.; Schwarz, C.; Seidel, W.; Serfling, V.; Trzcinski, A.; Tucholski, A.; Verde, G.

    1995-02-01

    Fragment distributions resulting from Au+Au collisions at an incident energy of E/A=600 MeV are studied. From the measured fragment and neutron distributions the mass and the excitation energy of the decaying pre-fragments were determined. A temperature scale was derived from observed yield ratios of He and Li isotopes. The relation between this isotope temperature and the excitation energy of the system exhibits a behavior which is expected for a phase transition. The nuclear vapor regime takes over at an excitation energy of 10 MeV per nucleon, a temperature of 5 MeV and may be characterized by a density of 0.15-0.3 normal nuclear density. (orig.)

  5. Application of atomic mutations included in nuclear reactions, 40Ar(γ, p)39Cl(β decay)39Ar, to surface study

    International Nuclear Information System (INIS)

    Ohkuma, Juzo

    1987-01-01

    It has been found that the nuclear transformation processes which are initiated by photonuclear reactions can be used for studying the adsorption and chemical reactions taking place on solid surfaces. Chemically reactive 39 Cl was produced by irradiating 40 Ar with high-energy bremsstrahlung, and its blow was directed onto several material surfaces. The amount of chlorine adsorption was ascertained by detecting its radioactivity. Desorption without heating the adsorber samples inevitably occurred owing to the nuclear decay of 39 Cl. The adsorption and desorption rates were compared for several elements. A fast growth of oxide islands on sample surfaces was observed during the adsorption-desorption process. (author)

  6. An effective potential for electron-nucleus scattering in neutrino-pair bremsstrahlung in neutron star crust

    International Nuclear Information System (INIS)

    Ofengeim, D D; Kaminker, A D; Yakovlev, D G

    2015-01-01

    We derive an analytic approximation for the emissivity of neutrino-pair bremsstrahlung (NPB) due to scattering of electrons by atomic nuclei in a neutron star (NS) crust of any realistic composition. The emissivity is expressed through generalized Coulomb logarithm by introducing an effective potential of electron-nucleus scattering. In addition, we study the conditions at which NPB in the crust is affected by strong magnetic fields and outline the main effects of the fields on neutrino emission in NSs. The results can be used for modelling of many phenomena in NSs, such as cooling of young isolated NSs, thermal relaxation of accreting NSs with overheated crust in soft X-ray transients and evolution of magnetars. (paper)

  7. Simulations of Beam Optics and Bremsstrahlung for High Intensity and Brightness Channeling Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, J. [Sokendai, Tsukuba; Piot, P. [NIU, DeKalb; Sen, T. [Fermilab

    2018-04-12

    This paper presents X-ray spectra of channeling radiation expected at the FAST (Fermi Accelerator Science and Technology) facility in Fermilab. Our purpose is to produce high brightness quasi-monochromatic X-rays in an energy range from 40 keV to 110 keV. We will use a diamond crystal and low emittance electrons with an energy of around 43 MeV. The quality of emitted X-rays depends on parameters of the electron beam at the crystal. We present simulations of the beam optics for high brightness and high yield operations for a range of bunch charges. We estimate the X-ray spectra including bremsstrahlung background. We discuss how the electron beam distributions after the diamond crystal are affected by channeling. We discuss an X-ray detector system to avoid pile-up effects during high charge operations.

  8. BPS Wilson loops and Bremsstrahlung function in ABJ(M): a two loop analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, Marco S. [Institut für Physik, Humboldt-Universität zu Berlin,Newtonstraße 15, 12489 Berlin (Germany); Griguolo, Luca [Dipartimento di Fisica e Scienze della Terra, Università di Parmaand INFN Gruppo Collegato di Parma,Viale G.P. Usberti 7/A, 43100 Parma (Italy); Leoni, Matias [Physics Department, FCEyN-UBA & IFIBA-CONICETCiudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Penati, Silvia [Dipartimento di Fisica, Università di Milano-Bicoccaand INFN, Sezione di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Seminara, Domenico [Dipartimento di Fisica, Università di Firenzeand INFN Sezione di Firenze,via G. Sansone 1, 50019 Sesto Fiorentino (Italy)

    2014-06-19

    We study a family of circular BPS Wilson loops in N=6 super Chern-Simons-matter theories, generalizing the usual 1/2-BPS circle. The scalar and fermionic couplings depend on two deformation parameters and these operators can be considered as the ABJ(M) counterpart of the DGRT latitudes defined in N=4 SYM. We perform a complete two-loop analysis of their vacuum expectation value, discuss the appearance of framing-like phases and propose a general relation with cohomologically equivalent bosonic operators. We make an all-loop proposal for computing the Bremsstrahlung function associated to the 1/2-BPS cusp in terms of these generalized Wilson loops. When applied to our two-loop result it reproduces the known expression. Finally, we comment on the generalization of this proposal to the bosonic 1/6-BPS case.

  9. Hydramite II screening tests of potential bremsstrahlung converter debris shield materials

    International Nuclear Information System (INIS)

    Reedy, E.D. Jr.; Hedemann, M.A.; Stark, M.A.

    1986-03-01

    Results of a brief test series aimed at screening a number of potential bremsstrahlung converter debris shield materials are reported. These tests were run on Sandia National Laboratories' Hydramite II accelerator using a diode configuration which produces a pinched electron beam. The materials tested include: (1) laminated Kevlar 49/polyester and E-glass/polyester composites, (2) a low density laminated Kevlar 49 composite, and (3) two types of through-the-thickness reinforced Kevlar 49 composites. As expected, tests using laminated Kevlar 49/polyester shields showed that shield permanent set (i.e., permanent deflection) increased with increasing tantalum conversion foil thickness and decreased with increasing shield thickness. The through-the-thickness reinforced composites developed localized, but severe, back surface damage. The laminated composites displayed little back surface damage, although extensive internal matrix cracking and ply delaminations were generated. Roughly the same degree of permanent set was produced in shields made from the low density Kevlar 49 composite and the Kevlar 49/polyester. The E-glass reinforced shields exhibited relatively low levels of permanent set

  10. Working group report on hadrons in the nuclear medium

    Energy Technology Data Exchange (ETDEWEB)

    Ent, R. [CEBAF, Newport News, VA (United States); Milner, R.G. [Masachusetts Inst. of Technology, Cambridge, MA (United States)

    1994-04-01

    This working group focussed on the subject of hadrons in the nuclear medium. It encompassed both the understanding of the nucleus itself in terms of its binding and its structure, and the use of the nucleus as a medium to probe QCD and the structure of hadrons. Both aspects were addressed during the workshop, though the emphasis tended towards the latter. Almost inescapably this working group had some overlap with the other working groups, as the nucleus can also be used as a medium to probe the production and structure of vector mesons. Also, inclusive and semi-inclusive processes can be used as a probe of nuclear effects, for instance in the case of deep-inelastic scattering for x > 1. In this summary report the authors will try to restrict themselves to only those issues where the nuclear medium is important. To increase their understanding of the nucleus in terms of its binding and structure, they would like to know the effect of a dense nuclear medium on a nucleon, to know the non-nucleonic degrees of freedom needed to describe a nuclear system, and to understand the implications of the fact that a bound nucleon is necessarily off its mass-shell. The results of many lepton scattering experiments during the last two decades have raised these questions, but at this moment there are no definitive answers. The hope is that the well-known electron probe, with sufficient energy to probe the short-range properties of nuclei, can provide insight. Especially, the authors would like a conclusive answer to the question if, and to what extent, quark degrees of freedom are necessary to describe a nuclear system.

  11. Working group report on hadrons in the nuclear medium

    International Nuclear Information System (INIS)

    Ent, R.; Milner, R.G.

    1994-01-01

    This working group focussed on the subject of hadrons in the nuclear medium. It encompassed both the understanding of the nucleus itself in terms of its binding and its structure, and the use of the nucleus as a medium to probe QCD and the structure of hadrons. Both aspects were addressed during the workshop, though the emphasis tended towards the latter. Almost inescapably this working group had some overlap with the other working groups, as the nucleus can also be used as a medium to probe the production and structure of vector mesons. Also, inclusive and semi-inclusive processes can be used as a probe of nuclear effects, for instance in the case of deep-inelastic scattering for x > 1. In this summary report the authors will try to restrict themselves to only those issues where the nuclear medium is important. To increase their understanding of the nucleus in terms of its binding and structure, they would like to know the effect of a dense nuclear medium on a nucleon, to know the non-nucleonic degrees of freedom needed to describe a nuclear system, and to understand the implications of the fact that a bound nucleon is necessarily off its mass-shell. The results of many lepton scattering experiments during the last two decades have raised these questions, but at this moment there are no definitive answers. The hope is that the well-known electron probe, with sufficient energy to probe the short-range properties of nuclei, can provide insight. Especially, the authors would like a conclusive answer to the question if, and to what extent, quark degrees of freedom are necessary to describe a nuclear system

  12. Operation of LIA-30 linear induction accelerator in the mode of generation of two bremsstrahlung pulses

    Energy Technology Data Exchange (ETDEWEB)

    Bossamykin, V S; Gerasimov, A I; Gordeev, V S; Grishin, A V; Gritsina, V P; Tarasov, A D; Fedotkin, A S; Lazarev, S A; Averchenkov, A Ya [All-Russian Scientific Research Institute of Experimental Physics, Sarov (Russian Federation)

    1997-12-31

    The operating mode was studied of the LIA-30 linear induction accelerator ({approx} 40 MeV, {approx} 100 kA, {approx} 30 ns) with the generation of two bremsstrahlung pulses separated by a specified time interval from 0 to 5 {mu}s. In the accelerating channel an additional tube cathode was installed, and a synchronization system for two accelerating module groups triggering the formation and acceleration, at different initial times, of two annular electron beams with different outer diameters was changed. The energy limit of each beam electron acceleration can be controlled, and the energy sum limit is {<=} 540 MeV. (author). 2 tabs., 2 figs.

  13. Medium energy probes and nuclear structure

    International Nuclear Information System (INIS)

    Ginocchio, J.N.

    1984-01-01

    In this paper we explore two topics. The first topic is the marriage of medium energy reaction theory with the interacting boson model of nuclei in such a way that the multiple scattering is summed to all orders. The second topic is an exactly solvable potential model which gives realistic shell model eigenfunctions which can be used to calculate static and transition nuclear densities. (orig./HSI)

  14. State special standard for bremsstrahlung energy flux unit in the range of maximum photon energy 0.8-8.0 pJ (5-50 MeV)

    International Nuclear Information System (INIS)

    Yudin, M.F.; Skotnikov, V.V.; Bruj, V.N.; Tsvetkov, I.I.; Fominykh, V.I.

    1976-01-01

    The state special standard is described, which improves the accuracy and ensures unification and correctness of measurements of a bremsstrahlung energy flux. The size of the unit is conveyed, by means of working standards and model measuring means, to working devices measuring the energy flux over a wide range

  15. Fluid-flow monitoring using electromagnetic probing

    International Nuclear Information System (INIS)

    Lytle, R.J.; Lager, D.L.; Laine, E.F.; Salisbury, J.D.; Okada, J.T.

    1979-01-01

    High-frequency electromagnetic probing is used to monitor the rate and direction of flow of fluids injected into the ground. This method shows the potential for providing more detailed information than procedures presently used. The experimental technique and the test-of-concept experimental results are discussed. This technique has applications in oil-reservoir engineering and in hydrology studies concerning storage of chemical and nuclear wastes. 11 figures

  16. New generation nuclear microprobe systems

    International Nuclear Information System (INIS)

    Jamieson, David N.

    2001-01-01

    Over the past 20 years, the minimum probe size for nuclear microscopy has stayed around 1 μm with only a few groups reporting a sub-micron probe size around 0.5 μm. No breakthroughs in nuclear microprobe design have been forthcoming to produce dramatic improvements in spatial resolution. The difficulties of breaking the constraints that are preventing reduction of the probe size have been well recognised in the past. Over the past 5 years it has become clear that some of these constraints may not be as limiting as first thought. For example, chromatic aberration clearly is not as significant as implied from first-order ion optics calculations. This paper reviews the constraints in view of the increased understanding of the past 5 years and looks at several new approaches, presently being evaluated in Melbourne and elsewhere, on how to make progress. These approaches include modified RF ion sources for improved beam brightness and exploitation of relaxed constraints on some lens aberrations allowing the use of high demagnification probe forming lens systems

  17. Probing the nuclear matter at high baryon and isospin density with heavy ion collisions

    International Nuclear Information System (INIS)

    Di Toro, M.; Colonna, M.; Ferini, G.

    2010-01-01

    Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. High Energy Collisions are studied in order to access nuclear matter properties at high density. Particular attention is devoted to the selection of observables sensitive to the poorly known symmetry energy at high baryon density, of large fundamental interest, even for the astrophysics implications. Using fully consistent covariant transport simulations built on effective field theories we are testing isospin observables ranging from nucleon/cluster emissions, collective flows (in particular the elliptic, squeeze out, part) and meson production. The possibility to shed light on the controversial neutron/proton effective mass splitting in asymmetric matter is also stressed. The "symmetry" repulsion at high baryon density will also lead to an "earlier" hadron-deconfinement transition in n-rich matter. The phase transition of hadronic to quark matter at high baryon and isospin density is analyzed. Nonlinear relativistic mean field models are used to describe hadronic matter, and the MIT bag model is adopted for quark matter. The boundaries of the mixed phase and the related critical points for symmetric and asymmetric matter are obtained. Isospin effects appear to be rather significant. The binodal transition line of the (T,ρ B ) diagram is lowered in a region accessible to heavy ion collisions in the energy range of the new planned FAIR/NICA facilities. Some observable effects of the mixed phase are suggested, in particular a neutron distillation mechanism. Theoretically a very important problem appears to be the suitable treatment of the isovector part of the interaction in effective QCD lagrangian approaches. (author)

  18. Probing the nuclear symmetry energy with heavy-ion collisions

    Directory of Open Access Journals (Sweden)

    De Filippo E.

    2015-01-01

    Full Text Available Heavy ion collisions (HIC have been widely used to extract the parametrization of symmetry energy term of nuclear equation of state as a function of barionic density. HIC in fact are a unique tool in terrestrial laboratories to explore the symmetry energy around the saturation density (ρ0 = 0.16fm−3 from sub-saturation densities (Fermi energies towards compressed nuclear matter (ρ > 2 − 3ρ0 that can be reached at relativistic energies, as a function of different conditions of temperature, mass asymmetry and isospin. One of the main study at present is to reach a coherent description of EOS of asymmetric nuclear matter from heavy ion collisions of stable and exotic nuclei, nuclear structure studies and astrophysical observations. In this work an overview of the current status of the research is shortly reviewed together with new perspectives aimed to reduce the present experimental and theoretical uncertainties.

  19. Benchmarking of Monte Carlo simulation of bremsstrahlung from thick targets at radiotherapy energies

    International Nuclear Information System (INIS)

    Faddegon, Bruce A.; Asai, Makoto; Perl, Joseph; Ross, Carl; Sempau, Josep; Tinslay, Jane; Salvat, Francesc

    2008-01-01

    Several Monte Carlo systems were benchmarked against published measurements of bremsstrahlung yield from thick targets for 10-30 MV beams. The quantity measured was photon fluence at 1 m per unit energy per incident electron (spectra), and total photon fluence, integrated over energy, per incident electron (photon yield). Results were reported at 10-30 MV on the beam axis for Al and Pb targets and at 15 MV at angles out to 90 degree sign for Be, Al, and Pb targets. Beam energy was revised with improved accuracy of 0.5% using an improved energy calibration of the accelerator. Recently released versions of the Monte Carlo systems EGSNRC, GEANT4, and PENELOPE were benchmarked against the published measurements using the revised beam energies. Monte Carlo simulation was capable of calculation of photon yield in the experimental geometry to 5% out to 30 degree sign , 10% at wider angles, and photon spectra to 10% at intermediate photon energies, 15% at lower energies. Accuracy of measured photon yield from 0 to 30 degree sign was 5%, 1 s.d., increasing to 7% for the larger angles. EGSNRC and PENELOPE results were within 2 s.d. of the measured photon yield at all beam energies and angles, GEANT4 within 3 s.d. Photon yield at nonzero angles for angles covering conventional field sizes used in radiotherapy (out to 10 degree sign ), measured with an accuracy of 3%, was calculated within 1 s.d. of measurement for EGSNRC, 2 s.d. for PENELOPE and GEANT4. Calculated spectra closely matched measurement at photon energies over 5 MeV. Photon spectra near 5 MeV were underestimated by as much as 10% by all three codes. The photon spectra below 2-3 MeV for the Be and Al targets and small angles were overestimated by up to 15% when using EGSNRC and PENELOPE, 20% with GEANT4. EGSNRC results with the NIST option for the bremsstrahlung cross section were preferred over the alternative cross section available in EGSNRC and over EGS4. GEANT4 results calculated with the ''low energy

  20. Benchmarking of Monte Carlo simulation of bremsstrahlung from thick targets at radiotherapy energies

    Energy Technology Data Exchange (ETDEWEB)

    Faddegon, Bruce A.; Asai, Makoto; Perl, Joseph; Ross, Carl; Sempau, Josep; Tinslay, Jane; Salvat, Francesc [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California 94143 (United States); Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); National Research Council Canada, Institute for National Measurement Standards, 1200 Montreal Road, Building M-36, Ottawa, Ontario K1A 0R6 (Canada); Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya and Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), Diagonal 647, 08028 Barcelona (Spain); Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Facultat de Fisica (ECM), Universitat de Barcelona, Societat Catalana de Fisica (IEC), Diagonal 647, 08028 Barcelona (Spain)

    2008-10-15

    Several Monte Carlo systems were benchmarked against published measurements of bremsstrahlung yield from thick targets for 10-30 MV beams. The quantity measured was photon fluence at 1 m per unit energy per incident electron (spectra), and total photon fluence, integrated over energy, per incident electron (photon yield). Results were reported at 10-30 MV on the beam axis for Al and Pb targets and at 15 MV at angles out to 90 degree sign for Be, Al, and Pb targets. Beam energy was revised with improved accuracy of 0.5% using an improved energy calibration of the accelerator. Recently released versions of the Monte Carlo systems EGSNRC, GEANT4, and PENELOPE were benchmarked against the published measurements using the revised beam energies. Monte Carlo simulation was capable of calculation of photon yield in the experimental geometry to 5% out to 30 degree sign , 10% at wider angles, and photon spectra to 10% at intermediate photon energies, 15% at lower energies. Accuracy of measured photon yield from 0 to 30 degree sign was 5%, 1 s.d., increasing to 7% for the larger angles. EGSNRC and PENELOPE results were within 2 s.d. of the measured photon yield at all beam energies and angles, GEANT4 within 3 s.d. Photon yield at nonzero angles for angles covering conventional field sizes used in radiotherapy (out to 10 degree sign ), measured with an accuracy of 3%, was calculated within 1 s.d. of measurement for EGSNRC, 2 s.d. for PENELOPE and GEANT4. Calculated spectra closely matched measurement at photon energies over 5 MeV. Photon spectra near 5 MeV were underestimated by as much as 10% by all three codes. The photon spectra below 2-3 MeV for the Be and Al targets and small angles were overestimated by up to 15% when using EGSNRC and PENELOPE, 20% with GEANT4. EGSNRC results with the NIST option for the bremsstrahlung cross section were preferred over the alternative cross section available in EGSNRC and over EGS4. GEANT4 results calculated with the &apos

  1. Far from the intermediate nuclear field

    International Nuclear Information System (INIS)

    Dietrich, K.; Wagner, G.J.; Gregoire, C.; Campi, X.; Silvestre-Brac, B.; Platchkov, S.; Mayer, B.; Abgrall, Y.; Bohigas, O.; Grange, P.; Signarbieux, C.

    1988-01-01

    Pairing correlations in nuclear physics; the BCS state and quasi-particles; the layer model; collision effects on nuclear dynamics; the theory of cluster formation (application to nucleus fragmentation); short range correlations (few-particle systems); deuterium electron scattering; dibaryonic resonances; traditional and exotic hadron probes of nuclear structure; spectral fluctuations and chaotic motion; corrections to the intermediate nuclear field (nonrelativistic and other effects); and heavy nuclei splitting and nuclear superfluidity are introduced [fr

  2. Probing the nuclear symmetry energy at high densities with nuclear reactions

    Science.gov (United States)

    Leifels, Y.

    2017-11-01

    The nuclear equation of state is a topic of highest current interest in nuclear structure and reactions as well as in astrophysics. The symmetry energy is the part of the equation of state which is connected to the asymmetry in the neutron/proton content. During recent years a multitude of experimental and theoretical efforts on different fields have been undertaken to constraint its density dependence at low densities but also above saturation density (ρ_0=0.16 fm ^{-3} . Conventionally the symmetry energy is described by its magnitude S_v and the slope parameter L , both at saturation density. Values of L = 44 -66MeV and S_v=31 -33MeV have been deduced in recent compilations of nuclear structure, heavy-ion reaction and astrophysics data. Apart from astrophysical data on mass and radii of neutron stars, heavy-ion reactions at incident energies of several 100MeV are the only means do access the high density behaviour of the symmetry energy. In particular, meson production and collective flows upto about 1 AGeV are predicted to be sensitive to the slope of the symmetry energy as a function of density. From the measurement of elliptic flow of neutrons with respect to charged particles at GSI, a more stringent constraint for the slope of the symmetry energy at supra-saturation densities has been deduced. Future options to reach even higher densities will be discussed.

  3. ''Yields of Radionuclides Created by Photonuclear Reactions on Be, C, Na, C1, and Ge, Using Bremsstrahlung of 150-MeV Electrons''

    Energy Technology Data Exchange (ETDEWEB)

    Dickens, J.K.

    2001-12-13

    The bremsstrahlung created by 150-MeV electrons impinging on a tantalum radiator was used to study photonuclear reactions on samples containing Be, C, Na, Cl and Ge. For Ge fifteen radioisotopes, ranging in half life between 2.6 min and 271 days, and in mass between 65 and 75, were obtained in sufficient amount to determine their yields quantitatively using known decay gamma-rays. Special equipment is described which was developed to create the bremsstrahlung using a beam-sharing mode, while minimizing the neutron flux on the sample. Relative production rates were determined. These were analyzed to provide absolute average cross sections for production of three reactions: <{sigma}> for {sup 35}Cl({gamma}, n) {sup 34}Cl{sup isom}- = 4.7 mb; <{sigma}> for {sup 70}Ge({gamma}, n){sup 69}Ge = 56 mb; and <{sigma}> for {sup 76}Ge({gamma}, n){sup 75}Ge = 53 mb, where the ({gamma}, n) values are averages over the giant resonances of the stable target isotopes.

  4. Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Christopher P., E-mail: cj0810@bristol.ac.uk [Interface Analysis Centre, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Brenner, Ceri M. [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX (United Kingdom); Stitt, Camilla A. [Interface Analysis Centre, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Armstrong, Chris; Rusby, Dean R. [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX (United Kingdom); Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Mirfayzi, Seyed R. [Centre for Plasma Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Wilson, Lucy A. [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX (United Kingdom); Alejo, Aarón; Ahmed, Hamad [Centre for Plasma Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Allott, Ric [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX (United Kingdom); Butler, Nicholas M.H. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Clarke, Robert J.; Haddock, David; Hernandez-Gomez, Cristina [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX (United Kingdom); Higginson, Adam [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Murphy, Christopher [Department of Physics, University of York, York YO10 5DD (United Kingdom); Notley, Margaret [Central Laser Facility, STFC, Rutherford Appleton Laboratory, Didcot, Oxon OX11 0QX (United Kingdom); Paraskevoulakos, Charilaos [Interface Analysis Centre, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Jowsey, John [Ground Floor North B582, Sellafield Ltd, Seascale, Cumbria CA20 1PG (United Kingdom); and others

    2016-11-15

    Highlights: • X-ray generation was achieved via laser interaction with a tantalum thin foil target. • Picosecond X-ray pulse from a sub-mm spot generated high resolution images. • MeV X-ray emission is possible, permitting analysis of full scale waste containers. • In parallel neutron emission of 10{sup 7}–10{sup 9} neutrons per steradian per pulse was attained. • Development of a 10 Hz diode pumped laser system for waste monitoring is envisioned. - Abstract: A small scale sample nuclear waste package, consisting of a 28 mm diameter uranium penny encased in grout, was imaged by absorption contrast radiography using a single pulse exposure from an X-ray source driven by a high-power laser. The Vulcan laser was used to deliver a focused pulse of photons to a tantalum foil, in order to generate a bright burst of highly penetrating X-rays (with energy >500 keV), with a source size of <0.5 mm. BAS-TR and BAS-SR image plates were used for image capture, alongside a newly developed Thalium doped Caesium Iodide scintillator-based detector coupled to CCD chips. The uranium penny was clearly resolved to sub-mm accuracy over a 30 cm{sup 2} scan area from a single shot acquisition. In addition, neutron generation was demonstrated in situ with the X-ray beam, with a single shot, thus demonstrating the potential for multi-modal criticality testing of waste materials. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material. With recent developments of high-power laser systems, to 10 Hz operation, a laser-driven multi-modal beamline for waste monitoring applications is envisioned.

  5. Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages

    International Nuclear Information System (INIS)

    Jones, Christopher P.; Brenner, Ceri M.; Stitt, Camilla A.; Armstrong, Chris; Rusby, Dean R.; Mirfayzi, Seyed R.; Wilson, Lucy A.; Alejo, Aarón; Ahmed, Hamad; Allott, Ric; Butler, Nicholas M.H.; Clarke, Robert J.; Haddock, David; Hernandez-Gomez, Cristina; Higginson, Adam; Murphy, Christopher; Notley, Margaret; Paraskevoulakos, Charilaos; Jowsey, John

    2016-01-01

    Highlights: • X-ray generation was achieved via laser interaction with a tantalum thin foil target. • Picosecond X-ray pulse from a sub-mm spot generated high resolution images. • MeV X-ray emission is possible, permitting analysis of full scale waste containers. • In parallel neutron emission of 10"7–10"9 neutrons per steradian per pulse was attained. • Development of a 10 Hz diode pumped laser system for waste monitoring is envisioned. - Abstract: A small scale sample nuclear waste package, consisting of a 28 mm diameter uranium penny encased in grout, was imaged by absorption contrast radiography using a single pulse exposure from an X-ray source driven by a high-power laser. The Vulcan laser was used to deliver a focused pulse of photons to a tantalum foil, in order to generate a bright burst of highly penetrating X-rays (with energy >500 keV), with a source size of <0.5 mm. BAS-TR and BAS-SR image plates were used for image capture, alongside a newly developed Thalium doped Caesium Iodide scintillator-based detector coupled to CCD chips. The uranium penny was clearly resolved to sub-mm accuracy over a 30 cm"2 scan area from a single shot acquisition. In addition, neutron generation was demonstrated in situ with the X-ray beam, with a single shot, thus demonstrating the potential for multi-modal criticality testing of waste materials. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material. With recent developments of high-power laser systems, to 10 Hz operation, a laser-driven multi-modal beamline for waste monitoring applications is envisioned.

  6. Characteristics Testing of the ECT Bobbin Probe for Steam Generator Tube Inspection of Nuclear Power Plant

    International Nuclear Information System (INIS)

    Nam, Min Woo; Lee, Hee Jong; Cho, Chan hee; Yoo, Hyun Joo

    2010-01-01

    The steam generator management program(SGMP) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. The first way is to qualify the equipment or the probe by using the flaw mechanism and method of the pulled tubes from the heat exchangers or the artificial flawed tubes. The second way is to verify the equivalency with the characteristics of the qualified equipment or probe. In this case, the qualified equipment or probe may be modified to substitute or replace instruments or probes without re-qualification provided that the range of essential variables defined in the examination technique specification sheet are met. This study is to describe the result of the comparative performance evaluation of bobbin coil eddy current probes manufactured by KEPCO Research Institute and probes manufactured by a foreign manufacturer. As a result of this study, although there were minor differences between the two kinds of probes, it was evaluated that the two kinds of probes were almost identical in the significant performance characteristics described in the KEPCO Research Institute guideline

  7. Characteristics Testing of the ECT Bobbin Probe for Steam Generator Tube Inspection of Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Min Woo; Lee, Hee Jong; Cho, Chan hee; Yoo, Hyun Joo [KEPCO, Daejeon (Korea, Republic of)

    2010-08-15

    The steam generator management program(SGMP) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. The first way is to qualify the equipment or the probe by using the flaw mechanism and method of the pulled tubes from the heat exchangers or the artificial flawed tubes. The second way is to verify the equivalency with the characteristics of the qualified equipment or probe. In this case, the qualified equipment or probe may be modified to substitute or replace instruments or probes without re-qualification provided that the range of essential variables defined in the examination technique specification sheet are met. This study is to describe the result of the comparative performance evaluation of bobbin coil eddy current probes manufactured by KEPCO Research Institute and probes manufactured by a foreign manufacturer. As a result of this study, although there were minor differences between the two kinds of probes, it was evaluated that the two kinds of probes were almost identical in the significant performance characteristics described in the KEPCO Research Institute guideline

  8. Photoinduced molecular chirality probed by ultrafast resonant X-ray spectroscopy

    Directory of Open Access Journals (Sweden)

    Jérémy R. Rouxel

    2017-07-01

    Full Text Available Recently developed circularly polarized X-ray light sources can probe the ultrafast chiral electronic and nuclear dynamics through spatially localized resonant core transitions. We present simulations of time-resolved circular dichroism signals given by the difference of left and right circularly polarized X-ray probe transmission following an excitation by a circularly polarized optical pump with the variable time delay. Application is made to formamide which is achiral in the ground state and assumes two chiral geometries upon optical excitation to the first valence excited state. Probes resonant with various K-edges (C, N, and O provide different local windows onto the parity breaking geometry change thus revealing the enantiomer asymmetry.

  9. New molecular probes of vascular inflammation

    International Nuclear Information System (INIS)

    Molecular Cardiovascular Imaging, Westfälische Wilhelms University Münster, Münster, (Germany))" data-affiliation=" (Department of Nuclear Medicine, University Hospital Münster, Münster, and DFG CRC 656 Molecular Cardiovascular Imaging, Westfälische Wilhelms University Münster, Münster, (Germany))" >VRACHIMIS, Alexis; HONOLD, Lisa; Cells in Motion Cluster of Excellence, Westfälische Wilhelms University Münster, Münster, (Germany))" data-affiliation=" (European Institute of Molecular Imaging, Westfälische Wilhelms University Münster, Münster, and DFG EXC 1003 Cells in Motion Cluster of Excellence, Westfälische Wilhelms University Münster, Münster, (Germany))" >FAUST, Andreas; Cells in Motion Cluster of Excellence, Westfälische Wilhelms University Münster, Münster, (Germany))" data-affiliation=" (European Institute of Molecular Imaging, Westfälische Wilhelms University Münster, Münster, and DFG EXC 1003 Cells in Motion Cluster of Excellence, Westfälische Wilhelms University Münster, Münster, (Germany))" >HERMANN, Sven; SCHÄFERS, Michael

    2016-01-01

    New molecular imaging approaches featuring the assessment of inflammatory processes in the vascular wall on top of existing anatomic and functional vessel imaging procedures could emerge as decisive tools for the understanding and prevention of cardiovascular events. In this respect imaging approaches addressing specific molecular and cellular targets in atherosclerosis are of high interest. This review summarizes the rationale and current status of nuclear imaging probes which possess high translational potential.

  10. Internal bremsstrahlung spectral shapes of 45Ca and 35S

    International Nuclear Information System (INIS)

    Babu, R.P.; Murty, K.N.; Murty, V.A.N.

    1976-01-01

    The internal bremsstrahlung spectra emitted in the beta decays of 45 Ca and 35 S were measured using a multichannel NaI(Tl) scintillation spectrometer with a standard geometrical arrangement. After making all the necessary corrections, the experimental results were compared with the allowed theory of Knipp and Uhlenbeck (Physica; 3:425 (1936)) and of Bloch (Phys. Rev.; 50:272 (1936)) (KUB theory) and also with the Coulomb-corrected theories of Lewis and Ford (Phys. Rev.; 107:756 (1957)) and of Nilsson (Ark. Fys.; 10:467 (1956)). In the case of 45 Ca, fairly good agreement with KUB theory was obtained from 30 to 155 keV and above 155 keV the experimental results were in agreement with the Lewis and Ford theory up to 210 keV, the maximum limit of the photon energy investigated. For 35 S, the experimental results are in quite good agreement with KUB theory from 25 to 45 keV, but beyond 45 keV the values are greater than the Coulomb-corrected theories due to both Lewis and Ford and to Nilsson, the experimental excess over Nilsson Coulomb-corrected theory being by factors of 1.07, 1.12 and 1.63 at energies 60, 90 and 110 keV respectively. (author)

  11. System size and beam energy effects on probing the high-density behavior of nuclear symmetry energy with pion ratio

    International Nuclear Information System (INIS)

    Zhang Ming; Xiao Zhigang; Li Baoan; Chen Liewen; Yong Gaochan; Zhu Shengjiang

    2010-01-01

    Based on the isospin-and momentum-dependent hadronic transport model IBUU04, we have investigated the π - /π + ratio in the following three reactions: 48 Ca+ 48 Ca, 124 Sn + 124 Sn and 197 Au + 197 Au with nearly the same isospin asymmetry but different masses, at the bombarding energies from 0.25 to 0.6 AGeV. It is shown that the sensitivity of probing the E sym (ρ) with π - /π + increases with increasing the system size or decreasing the beam energy, showing a correlation to the degree of isospin fractionation. Therefore, with a given isospin asymmetry, heavier system at energies near the pion threshold is preferential to study the behavior of nuclear symmetry energy at supra-saturation densities.

  12. Nuclear reaction models - source term estimation for safety design in accelerators

    International Nuclear Information System (INIS)

    Nandy, Maitreyee

    2013-01-01

    Accelerator driven subcritical system (ADSS) employs proton induced spallation reaction at a few GeV. Safety design of these systems involves source term estimation in two steps - multiple fragmentation of the target and n+γ emission through a fast process followed by statistical decay of the primary fragments. The prompt radiation field is estimated in the framework of quantum molecular dynamics (QMD) theory, intra-nuclear cascade or Monte Carlo calculations. A few nuclear reaction model codes used for this purpose are QMD, JQMD, Bertini, INCL4, PHITS, followed by statistical decay codes like ABLA, GEM, GEMINI, etc. In the case of electron accelerators photons and photoneutrons dominate the prompt radiation field. High energy photon yield through Bremsstrahlung is estimated in the framework of Born approximation while photoneutron production is calculated using giant dipole resonance and quasi-deuteron formation cross section. In this talk hybrid and exciton PEQ models and QMD formalism will be discussed briefly

  13. Inverse Bremsstrahlung Stabilization of Noise in the Generation of Ultra-short Intense Pulses by Backward Raman Amplification

    International Nuclear Information System (INIS)

    Berger, Richard L.; Clark, Daniel S.; Solodov, Andrei; Valeo, Ernest J.; Fisch, Nathaniel J.

    2003-01-01

    Inverse bremsstrahlung absorption of the pump laser beam in a backward Raman amplifier over the round-trip light transit time through the sub-critical density plasma can more than double the electron temperature of the plasma and produce time-varying axial temperature gradients. The resulting increased Landau damping of the plasma wave and detuning of the resonance can act to stabilize the pump against unwanted amplification of Langmuir noise without disrupting nonlinear amplification of the femtosecond seed pulse. Because the heating rate increases with the charge state Z, only low-Z plasmas (hydrogen, helium, or helium-hydrogen mixtures) will maintain a low enough temperature for efficient operation

  14. Dosimetry and microdosimetry using LET spectrometer based on the track-etch detector: radiotherapy Bremsstrahlung beam, onboard aircraft radiation field

    International Nuclear Information System (INIS)

    Jadrnickova, I.; Spurny, F.

    2006-01-01

    The spectrometer of linear energy transfer (Let) based on the chemically etched poly-allyl-diglycol-carbonate (P.A.D.C.) track-etch detector was developed several years ago in our institute. This Let spectrometer enables determining Let of particles approximately from 10 to 700 keV/μm. From the Let spectra, dose characteristics can be calculated. The contribution presents the Let spectra and other dosimetric characteristics obtained onboard a commercial aircraft during more than 6 months long exposure and in the 18 MV radiotherapy Bremsstrahlung beam. (authors)

  15. Lasers probe the atomic nucleus

    International Nuclear Information System (INIS)

    Eastham, D.

    1986-01-01

    The article is contained in a booklet on the Revised Nuffield Advanced Physics Course, and concentrates on two techniques to illustrate how lasers probe the atomic nucleus. Both techniques employ resonance fluorescence spectroscopy for obtaining atomic transition energies. The first uses lasers to determine the change in the nuclear charge radius with isotope, the second concerns the use of lasers for ultrasensitive detection of isotopes and elements. The application of lasers in resonance ionization spectroscopy and proton decay is also described. (UK)

  16. Photospallation reactions of 133Cs and 139La by 100 MeV- and 200 MeV bremsstrahlungs

    International Nuclear Information System (INIS)

    Sakamoto, K.; Toramoto, H.; Hamajima, Y.; Okada, K.; Dohniwa, M.

    1984-01-01

    Spallation yields relative to the 196 Au yield from 197 Au(γ,n) of 26 to 46 nuclides of Sb, Te, I, Xe, Cs and/or Ba and La from 133 Cs and 139 La targets irradiated with bremsstrahlungs of end energies of 100 MeV and 200 MeV were radiochemically determined. The isomeric yield ratios for 132 La and 131 Ba from the ( 139 La + 100 MeV-γ), 132 La, 131 Ba, 121 Te and 119 Te from the ( 139 La + 200 MeV-γ, and 120 I, 121 Te and 119 Te from the ( 133 Cs +- 200 MeV-γ) were also determined. The isotopic yields from the (γ,yn) reactions decrease exponentially with increase of y up to 5, and show no dependence on energy and targets studied, indicating that the reactions of a few neutron emissions occur at energies lower than 100 MeV. When the product yields from the (γ,xpyn) reactions were plotted against (x + y) for each x (isotopic distribution), a regular variation of the Gaussian distributions, typical of nuclear spallation, was observed. Isobaric mass distributions and charge dispersions were deduced to extract characteristic features of these reactions. The isobaric distributions due only to photons of 100 MeV to 200 MeV, which were obtained by subtracting the 100 MeV-yields from the 200 MeV-yields, are very close to a symmetric one peaking at about 8 amu from the target masses. Nuclear charges are also dispersed symmetrically, with most probable N/Zsub(p) of about 1.3 replaced by about 1 amu to the neutron-deficient side from the beta stability valley in all the cases studied. Parameters included in Rudstam's semi-empirical formula were examined by comparing with the observed yield curves. The P values of 0.45 and 0.65, chosen for a better fit to the 200 MeV data on 133 Cs and 139 La, respectively, were larger than the predictions reported in the literature. The magic number effects of 139 La may explain the target-differences in mass distributions. (orig.)

  17. Time-resolved electron thermal conduction by probing of plasma formation in transparent solids with high power subpicosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Brian -Tinh Van [Univ. of California, Davis, CA (United States)

    1994-02-01

    This dissertation work includes a series of experimental measurements in a search for better understanding of high temperature (104-106K) and high density plasmas (1022-1024cm-3) produced by irradiating a transparent solid target with high intensity (1013 - 1015W/cm2) and subpicosecond (10-12-10-13s) laser pulses. Experimentally, pump and probe schemes with both frontside (vacuum-plasma side) and backside (plasma-bulk material side) probes are used to excite and interrogate or probe the plasma evolution, thereby providing useful insights into the plasma formation mechanisms. A series of different experiments has been carried out so as to characterize plasma parameters and the importance of various nonlinear processes. Experimental evidence shows that electron thermal conduction is supersonic in a time scale of the first picosecond after laser irradiation, so fast that it was often left unresolved in the past. The experimental results from frontside probing demonstrate that upon irradiation with a strong (pump) laser pulse, a thin high temperature (~40eV) super-critical density (~1023/cm3) plasma layer is quickly formed at the target surface which in turn becomes strongly reflective and prevents further transmission of the remainder of the laser pulse. In the bulk region behind the surface, it is also found that a large sub-critical (~1018/cm3) plasma is produced by inverse Bremsstrahlung absorption and collisional ionization. The bulk underdense plasma is evidenced by large absorption of the backside probe light. A simple and analytical model, modified from the avalanche model, for plasma evolution in transparent materials is proposed to explain the experimental results. Elimination of the bulk plasma is then experimentally illustrated by using targets overcoated with highly absorptive films.

  18. Improvement of gamma-ray Sn transport calculations including coherent and incoherent scatterings and secondary sources of bremsstrahlung and fluorescence: Determination of gamma-ray buildup factors

    International Nuclear Information System (INIS)

    Kitsos, S.; Diop, C.M.; Assad, A.; Nimal, J.C.; Ridoux, P.

    1996-01-01

    Improvements of gamma-ray transport calculations in S n codes aim at taking into account the bound-electron effect of Compton scattering (incoherent), coherent scattering (Rayleigh), and secondary sources of bremsstrahlung and fluorescence. A computation scheme was developed to take into account these phenomena by modifying the angular and energy transfer matrices, and no modification in the transport code has been made. The incoherent and coherent scatterings as well as the fluorescence sources can be strictly treated by the transfer matrix change. For bremsstrahlung sources, this is possible if one can neglect the charged particles path as they pass through the matter (electrons and positrons) and is applicable for the energy range of interest for us (below 10 MeV). These improvements have been reported on the kernel attenuation codes by the calculation of new buildup factors. The gamma-ray buildup factors have been carried out for 25 natural elements up to 30 mean free paths in the energy range between 15 keV and 10 MeV

  19. The art of predicting nuclear masses

    International Nuclear Information System (INIS)

    Hirsch, J.G.; Morales, I.; Mendoza-Temis, J.; Frank, A.; Lopez-Vieyra, J.C.; Barea, J.; Pittel, S.; Van Isacker, P.; Velazquez, V.

    2008-01-01

    A review of recent advances in the theoretical analysis of nuclear mass models and their predictive power is presented. After introducing two tests which probe the ability of nuclear mass models to extrapolate, three models are analyzed in detail: the liquid drop model (LDM), the liquid drop model plus empirical shell corrections (LDMM) and the Duflo–Zuker mass formula (DZ). The DZ model is exhibited as the most predictive model. The Garvey–Kelson mass relations are also discussed. It is shown that their fulfillment probes the consistency of the most commonly used mass formulae, and that they can be used in an iterative process to predict nuclear masses in the neighborhood of nuclei with measured masses, offering a simple and reproducible procedure for short range mass predictions. (author)

  20. Paramagnetic probes to study PrNi5?

    International Nuclear Information System (INIS)

    Hutchinson, W.D.; Harker, S.J.; Stewart, G.A.; Chaplin, D.H.; Kaplan, N.

    1996-01-01

    The Van-Vleck paramagnet PrNi 5 has been the focus of many studies in the past as a result of its usefulness as a nuclear cooling agent. Extensive continuous wave praseodymium NMR measurements have been carried out on this compound. However pulsed NMR and therefore precise relaxation measurements particularly at mK temperatures have proved elusive. In this work we have proposed to use radiative gamma-ray detection to indirectly measure Pr NMR in PrNi 5 via cross relaxation to suitable paramagnetic impurity probes placed at Ni lattice sites. 57 Co was chosen as the most compatible nuclear orientation isotope with an appropriate nuclear g-factor. The choice of 57 Co also allows the use of Moessbauer spectroscopy to check the site occupancy. This poster details the production of a 57 Co doped PrNi 5 single crystal specimen including the specimen preparation problems encountered, 57 Fe Moessbauer and preliminary nuclear orientation measurements

  1. Waveguide volume probe for magnetic resonance imaging and spectroscopy

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to a probe for use within the field of nuclear magnetic resonance, such as magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS)). One embodiment relates to an RF probe for magnetic resonance imaging and/or spectroscopy comprising a conductive...... non-magnetic hollow waveguide having an internal volume and at least one open end, one or more capacitors and at least a first conductive non-magnetic wire, wherein said first conductive wire connects at least one of said one or more capacitors to opposite walls of one open end of the waveguide...

  2. Nuclear physics

    International Nuclear Information System (INIS)

    Warner, D.D.; Aitken, T.W.; Rowley, N.

    1989-01-01

    The many diverse programmes of fundamental research and technical development at the Daresbury Nuclear Structure Facility (NSF) have continued at their usual hectic pace throughout the period 1988/89. An overview of the overall programme and of the Facility has been presented in the first volume of this report, along with an expanded discussion of some of the highlights of the year's work. This second volume presents the more technical and detailed reports on the progress and results of individuals proposals and hence will be of most interest to the more expert reader. The reports are grouped in terms of experimental studies aimed at probing the structure of individual nuclei or series of nuclei, studies devoted to probing the primary nuclear reaction mechanism itself, theoretical work and research devoted to the development of the accelerator, and experimental equipment/techniques. Overall, they provide a concise summary of the year's work at the NSF. (author)

  3. Photon correlation: a micrometer of the nuclear reaction

    International Nuclear Information System (INIS)

    Marques, F.M.

    1997-01-01

    The technique of intensity interferometry was largely applied to pairs of bosons produced in heavy ion collisions to study the properties of their source. Recently this technique was applied also to photons which can be considered 'natural' probes in interferometry. The analysis of the results of two experiments, namely Kr + Mi at 60 MeV/N and Ta + Au at 40 MeV/N carried out with the multidetector TAPS at GANIL has shown the complexity of the space-time characteristic of the photon source. The standard hypothesis describing the production of high energy protons (E γ > 25 MeV) as starting from p-n Bremsstrahlung exclusively in the initial superposition of the two nuclei was rejected. Actually the typical form of the correlation function in which the correlation width corresponds to the inverse of the source size, is not satisfied by any of the two systems. Only, by the taking into account in the BUU calculations the photons produced later bring near the calculations and the data. This late production could originate in the recompression of the di-nuclei system. In analogy with previous application of this technique to stellar interferometry we have studied the structure of the photon source by Monte-Carlo calculations of the correlation function. For the simple case of a binary source the correlation function is dependent on the two source distributions, relative intensity and the space-time separation of the two sources. The results of this calculations evidence the sensitivity of the photon interferometry to different reaction mechanisms by the magnitude and also the shape of the correlation function. The best agreement with the data is obtained when the two nuclear fragments emit simultaneously the photons at a moment subsequent to the reaction moment

  4. Probe code: a set of programs for processing and analysis of the left ventricular function - User's manual

    International Nuclear Information System (INIS)

    Piva, R.M.V.

    1987-01-01

    The User's Manual of the Probe Code is an addendum to the M.Sc. thesis entitled A Microcomputer System of Nuclear Probe to Check the Left Ventricular Function. The Probe Code is a software which was developed for processing and off-line analysis curves from the Left Ventricular Function, that were obtained in vivo. These curves are produced by means of an external scintigraph probe, which was collimated and put on the left ventricule, after a venous inoculation of Tc-99 m. (author)

  5. Resonant parametric interference effect in spontaneous bremsstrahlung of an electron in the field of a nucleus and two pulsed laser waves

    Science.gov (United States)

    Lebed', A. A.; Padusenko, E. A.; Roshchupkin, S. P.; Dubov, V. V.

    2018-04-01

    Electron-nucleus bremsstrahlung in the field of two moderately strong pulsed laser waves in the case of incommensurate frequencies is theoretically studied under resonant conditions. The process is studied in detail in a special kinematic region, where stimulated processes with correlated emission and absorption of photons of the first and second waves become predominant (parametric interference effect). The availability of this region is caused by interference of the first and second laser waves. The correspondence between the emission angle and the final-electron energy is established in this interference kinematic. In this case, the cross-sectional properties are determined by the multiphoton quantum interference parameter, which is proportional to the product of intensities of the first and second waves. The resonant differential cross section of electron-nucleus spontaneous bremsstrahlung with simultaneous registration of both emission angles of the spontaneous photon and the scattered electron can exceed by four or five orders of magnitude the corresponding cross section in the absence of an external field. It was shown for nonrelativistic electrons that the resonant cross section of the studied process in the field of two pulsed laser waves within the interference region in two order of magnitude may exceed corresponding cross sections at other scattering kinematics. The obtained results may be experimentally verified, for example, by scientific facilities at sources of pulsed laser radiation (such as SLAC, FAIR, XFEL, ELI).

  6. International conference on spin observables of nuclear probes: Summary talk

    International Nuclear Information System (INIS)

    Garvey, G.T.

    1988-01-01

    A selected summary of the presentation and discussions at the 4th Telluride Conference is presented. The summary deals mainly with the effects of nuclear spin and isospin on the interaction between nucleons and their consequences in nuclear structure. 11 figs

  7. Electron spectroscopy in the fundamental process of electron-nucleus bremsstrahlung

    International Nuclear Information System (INIS)

    Hillenbrand, Pierre-Michel

    2013-07-01

    Within the scope of this thesis the fundamental process of electron-nucleus bremsstrahlung was studied in inverse kinematics at the Experimental Storage Ring ESR at GSI. For the system U 88+ + N 2 at 90 MeV/u it was shown, that by using inverse kinematics coincidence measurements between the scattered electron and the emitted photon can be performed for the case, in which the incoming electron transfers almost all of its kinetic energy onto the emitted photon. The sensitivity to the fundamental process could be achieved by measuring triple differential cross sections as a function of the emission angle of the photon and the scattered electron as well as the energy of the scattered electron. The optics of the magnetic electron spectrometer used were thoroughly revised and optimized to the experimental requirements. Analyzing different coincidences in this collision system, it was possible to determine the contributions to the electron distribution arising from radiative electron capture to the projectile continuum, nonradiative electron capture to the projectile continuum, and electron loss to the projectile continuum. The experimental results of each of these processes were compared to theoretical calculations. The electron spectra for the radiative and the nonradiative electron capture to continuum clearly reproduce the opposite asymmetry predicted by theory. Furthermore electron spectra for collisions of U 28+ with different gases were measured.

  8. Use of bremsstrahlung information for the nondestructive characterization of radioactive waste packages; Nutzung von Bremsstrahlungsinformation zur zerstoerungsfreien Charakterisierung radioaktiver Abfallgebinde

    Energy Technology Data Exchange (ETDEWEB)

    Rohrmoser, Benjamin Paul

    2016-11-10

    In order to minimize pseudo activity whilst storage of radioactive waste packages it is required to determine the nuclide inventory as precisely as possible. The in Gamma spectra contained parts of bremsstrahlung can be used to identify and quantify certain beta nuclides. For this an analytical method has been developed. This was mainly tested with beta-emitter Sr-90 and Tm-170, as well as commonly present gamma-emitters in laboratory scale and actual 200 liter waste packages. As a result, non-destructive determination of radioactive wastes can be conducted more precisely.

  9. Probing the Evolution of the Shell Structures in Exotic Nuclei

    International Nuclear Information System (INIS)

    De Angelis, Giacomo

    2008-01-01

    Magic numbers are a key feature in finite Fermion systems since they are strongly related to the underlying mean field. The size of the shell gaps and their evolution far from stability can be linked to the shape and symmetry of the nuclear mean field. Moreover the study of nuclei with large neutron/proton ratio allow to probe the density dependence of the effective interaction. Changes of the nuclear density and size in nuclei with increasing N/Z ratios are expected to lead to different nuclear symmetries and excitations. In this contribution I will discuss some selected examples which show the big potential of stable beams and of binary reactions for the study of the properties of the neutron-rich nuclear many body systems.

  10. The use of eddy current testing for nuclear fuel rods cladding evaluation

    International Nuclear Information System (INIS)

    Silva Junior, Silverio F. da; Alencar, Donizete A.; Brito, Mucio Jose D. de

    2007-01-01

    Nuclear fuel rods cladding must be tested after their manufacture and during their operational life. This paper describes a study about the use of eddy current test method as a nondestructive tool for nuclear fuel rods cladding evaluation. The experiments were carried out using two different probes: an external probe and an internal probe. The main goal was to verify the sensitivity of the eddy current test system, to develop calibration and reference standards and to establish the main capabilities and limitations presented by this test method for this application. (author)

  11. Ab initio determination of the nuclear quadrupole moments of 114In, 115In, and 117In

    International Nuclear Information System (INIS)

    Errico, Leonardo A.; Renteria, Mario

    2006-01-01

    We present here ab initio determinations of the nuclear-quadrupole moment Q of hyperfine-probe-nuclear states of three different In isotopes: the 5 + 192 keV excited state of 114 In (probe for nuclear quadrupole alignment spectroscopy), the 9/2 + ground state of 115 In (nuclear magnetic and nuclear quadrupole resonance probe), and the 3/2 + 659 keV excited state of 117 In (perturbed angular correlations probe). These nuclear-quadrupole moments were determined by comparing experimental nuclear-quadrupole frequencies to the electric field gradient tensor calculated with high accuracy at In sites in metallic indium within the density functional theory. These ab initio calculations were performed with the full-potential linearized augmented plane wave method. The results obtained for the quadrupole moments of 114 In [Q( 114 In)=-0.14(1) b] are in clear discrepancy with those reported in the literature [Q( 114 In)=+0.16(6) b and +0.739(12) b]. For 115 In and 117 In our results are in excellent agreement with the literature and in the last case Q( 117 In) is determined with more precision. In the case of Q( 117 In), its sign cannot be determined because standard γ-γ perturbed angular correlations experiments are not sensitive to the sign of the nuclear-quadrupole frequency

  12. Internal bremsstrahlung spectra of the allowed. beta. emitters /sup 32/P, /sup 35/S and /sup 45/Ca

    Energy Technology Data Exchange (ETDEWEB)

    Powar, M S; Singh, M [Punjabi Univ., Patiala (India). Dept. of Physics

    1976-01-01

    A study of Coulomb field effects in internal bremsstrahlung (IB) has been undertaken by measuring the IB spectra for the allowed beta emitters /sup 32/P, /sup 35/S and /sup 45/Ca in the photon energy intervals of 50 to 1600 keV, 25 to 150 keV and 30 to 240 keV respectively. The experimental results show increasing positive departures from the KUB and Coulomb-corrected theories of Lewis and Ford, and Nilsson, with decreasing beta end-point energy. In the case of /sup 35/S the experimental results are 40 % higher than the more exact theory of Struzynski and Pollock for this isotope.

  13. Nuclear reactor assembly

    International Nuclear Information System (INIS)

    Dorner, H.; Scholz, M.; Jungmann, A.

    1975-01-01

    A nuclear reactor assembly includes a reactor pressure tank having a substantially cylindrical side wall surrounded by the wall of a cylindrical cavity formed by a biological shield. A rotative cylindrical wall is interposed between the walls and has means for rotating it from outside of the shield, and a probe is carried by the rotative wall for monitoring the pressure tank's wall. The probe is vertically movable relative to the rotative cylindrical wall, so that by the probe's vertical movement and rotation of the rotative cylinder, the reactor's wall can be very extensively monitored. If the reactor pressure tank's wall fails, it is contained by the rotative wall which is backed-up by the shield cavity wall. (Official Gazette)

  14. Measurement of photo-neutron cross sections and isomeric yield ratios in the {sup 89}Y(γ,xn){sup 89-x}Y reactions at the bremsstrahlung end-point energies of 65, 70 and 75 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Tatari, Mansoureh [Yazd Univ. (Iran, Islamic Republic of). Physics Dept.; Naik, Haladhara [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.; Kim, Guinyun; Kim, Kwangsoo [Kyungpook National Univ., Daegu (Korea, Republic of). Dept. of Physics; Shin, Sung-Gyun; Cho, Moo-Hyun [Pohang Univ. of Science and Technology (Korea, Republic of). Div. of Advanced Nuclear Engineering

    2017-07-01

    The flux-weighted average cross sections of the {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reactions and the isomeric yield ratios of the {sup 87m,g}Y, {sup 86m,g}Y, and {sup 85m,g}Y radionuclides produced in these reactions with the bremsstrahlung end-point energies of 65, 70 and 75 MeV have been determined by an activation and off-line γ-ray spectrometric technique using the 100 MeV electron linac in Pohang Accelerator Laboratory, Korea. The theoretical {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reaction cross sections for mono-energetic photons have been calculated using the computer code TALYS 1.6. Then the flux-weighted theoretical values were obtained to compare with the present data. The flux-weighted experimental and theoretical {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reaction cross sections increase very fast from the threshold values to a certain bremsstrahlung energy, where the other reaction channels open up. Thereafter it remains constant a while and then slowly decreases with the increase of cross sections for other reactions. Similarly, the isomeric yield ratios of {sup 87m,g}Y, {sup 86m,g}Y and {sup 85m,g}Y in the {sup 89}Y(γ,xn; x=2-4){sup 89-x}Y reactions from the present work and literature data show an increasing trend from their respective threshold values to a certain bremsstrahlung energy. After a certain point of energy, the isomeric yield ratios increase slowly with the bremsstrahlung energy. These observations indicate the role of excitation energy and its partitioning in different reaction channels.

  15. Tables of nuclear constants for gamma activation analysis

    International Nuclear Information System (INIS)

    Randa, Z.; Kreisinger, F.

    1983-01-01

    Tables of nuclear data were compiled for the purpose of routine gamma (photon) activation analysis. The tables are arranged in two parts. The first one lists the radionuclides in the order of their atomic number. In the second one, the emitted gamma-ray photons are tabulated in the order of increasing energy. Tables contain the gamma emitters produced by the following photonuclear reactions: (#betta#,#betta#), (#betta#,n), (#betta#,p), (#betta#,p+n), (#betta#,2n), (#betta#,3n), (#betta#,4n), (#betta#,2p), (#betta#,α), (#betta#,α+n), (#betta#,α+p). This set corresponds to the maximum energy of the bremsstrahlung of roughly 45 MeV. The program for the output of the tabulated data allows the data as required for specific irradiation and measuring reduction of conditions (reaction thresholds, energy and intensity of gamma-rays, half-lives and target elements). (author)

  16. Monte Carlo wave-packet approach to trace nuclear dynamics in molecular excited states by XUV-pump-IR-probe spectroscopy

    Science.gov (United States)

    Jing, Qingli; Bello, Roger Y.; Martín, Fernando; Palacios, Alicia; Madsen, Lars Bojer

    2018-04-01

    Recent research interests have been raised in uncovering and controlling ultrafast dynamics in excited neutral molecules. In this work we generalize the Monte Carlo wave packet (MCWP) approach to XUV-pump-IR-probe schemes to simulate the process of dissociative double ionization of H2 where singly excited states in H2 are involved. The XUV pulse is chosen to resonantly excite the initial ground state of H2 to the lowest excited electronic state of 1Σu + symmetry in H2 within the Franck-Condon region. The delayed intense IR pulse couples the excited states of 1Σu + symmetry with the nearby excited states of 1Σg + symmetry. It also induces the first ionization from H2 to H2 + and the second ionization from H2 + to H++H+. To reduce the computational costs in the MCWP approach, a sampling method is proposed to determine in time the dominant ionization events from H2 to H2+. By conducting a trajectory analysis, which is a unique possibility within the MCWP approach, the origins of the characteristic features in the nuclear kinetic energy release spectra are identified for delays ranging from 0 to 140 fs and the nuclear dynamics in the singly excited states in H2 is mapped out.

  17. Pre-service baseline inspection using x-probe of Oconee replacement steam generators

    International Nuclear Information System (INIS)

    Addario, M.; Shipp, P.; Davis, K.; Fogal, C.

    2003-01-01

    The eddy current method has been the industry standard for inspecting steam generator tubing for many years and the level of sophistication of coil technology has continued to evolve during that time. State of the art array probe systems now employ multiple sensitivity zones in the probe to better detect and characterize defects in an efficient manner. Owners and regulators of nuclear power plants are interested in the most effective and efficient inspection possible. The ultimate goal has been to meet or exceed new and existing regulatory and design requirements by maximizing the quantity and quality of eddy current data collected while minimizing both the time needed to perform the inspection and the radiation exposure. The X-Probe is an example of this new eddy current array technology. Qualified to detect all types of known defects in steam generator tubing, the technology is comprised of a system of probe, data acquisition instrumentation, computer and human interface software. Recently, Duke Power, along with Babcock and Wilcox Canada and the system developer R/D Tech, collaborated to implement this technology in a first of a kind full scale pre-service inspection of replacement steam generators for Duke Power's Oconee nuclear generating station at Babcock and Wilcox Canada's Cambridge plant. The discussion in this paper will briefly describe the X-Probe technology, describe the system required to perform the inspection, present the general results of the inspection and finally draw some comparative benefit conclusions for both pre-service and in-service applications. (author)

  18. Nuclear structure theory. Annual technical progress report, July 1, 1975--September 30, 1976

    International Nuclear Information System (INIS)

    French, J.B.; Koltun, D.S.

    1976-01-01

    This report summarizes progress during the past year in the following areas of nuclear structure and reaction theory: Meson interactions with nucleons and nuclei, including elastic and inelastic scattering of pions, three-body theories of scattering and absorption of pions by deuterons, π-p bremsstrahlung, and multiple-excitation models for meson absorption by heavier nuclei. Studies of the inverse scattering problem including 1 S 0 nucleon-nucleon scattering; the relativistic two-body problem, particularly for relativistic effects at low energies: the unitary-pole expansion in nucleon-nucleon scattering with hard-core interactions. Statistical spectroscopy including: strength distributions and sum rules(both energy weighted and inverse energy weighted) for nuclear excitations; fluctuations and correlations in spectra, strengths and expectation values; studies of Garvey-Kelson and similar mass relationships; spectroscopy in huge spaces including spectral methods for renormalization of the interaction and for using (two + three)-body Skyrme interactions; technical aspects of operator averaging

  19. Chiral symmetry and nuclear matter equation of state

    Indian Academy of Sciences (India)

    In other words, we want to probe if, in the context of a two-body force model, the empirical ... action occurs by the surrounding nucleons through Pauli blocking and the nuclear mean field. Nuclear ... sigma and delta have been considered.

  20. Collective flow as a probe of heavy-ion reaction dynamics

    International Nuclear Information System (INIS)

    Awes, T.C.

    1997-01-01

    Collective flow of nuclear matter probes the dynamics of heavy-ion reactions and can provide information about the nuclear-matter equation of state. In particular, the incident energy dependences of collective flow may be a sensitive means to deduce the existence of a Quark Gluon Plasma phase in the equation of state. Collective flow measurements from 30 A MeV to 200 A GeV incident energies are briefly reviewed. Preliminary results on collective flow from the WA98 experiment at the CERN SPS are presented

  1. Probing properties of neutron stars with terrestrial nuclear reactions

    International Nuclear Information System (INIS)

    Li Baoan; Chen Liewen; Ko, C.M.; Steiner, Andrew W.; Yong Gaochan

    2006-01-01

    Heavy-ion reactions induced by neutron-rich nuclei provide the unique opportunity in terrestrial laboratories to constrain the nuclear symmetry energy Esym in a broad density range. A conservative constraint, 32(ρ/ρ0)0.7 < Esym(ρ) < 32(ρ/ρ0)1.1, around the nuclear matter saturation density ρ0 has recently been obtained from analyzing the isospin diffusion data within a transport model for intermediate energy heavy-ion reactions. This subsequently puts a stringent constraint on properties of neutron stars, especially their radii and cooling mechanisms

  2. Comparative analysis of hepatopulmonary shunt obtained from pretherapy 99mTc MAA scintigraphy and post-therapy 90Y Bremsstrahlung imaging in 90Y microsphere therapy.

    Science.gov (United States)

    Jha, Ashish Kumar A; Zade, Anand A; Rangarajan, Venkatesh; Purandare, Nilendu; Shah, Sneha A; Agrawal, Archi; Kulkarni, Suyash S; Shetty, Nitin

    2012-05-01

    (99m)Tc macroaggregate albumin (MAA) scintigraphy is routinely used to estimate the hepatopulmonary shunt (HPS) of (90)Y microspheres because of their comparable average particle sizes (20-30 µm). However, the MAA particle size can vary from 10 to 90 µm. Therefore, HPS computed from (99m)Tc MAA scintigraphy may not accurately represent the HPS of (90)Y microspheres. In view of this, the present study was undertaken to investigate the accuracy of (99m)Tc MAA scintigraphy in estimating the HPS of (90)Y microspheres. Nineteen sessions of transarterial radioembolization using (90)Y therasphere were carried out in 17 patients for hepatic malignancies (both primary and secondary). For each session of therapy, a pretherapeutic (99m)Tc MAA scintigraphy and post-therapeutic (90)Y Bremsstrahlung scintigraphy were performed. The HPSs obtained from these images were compared. The mean HPS fractions calculated from the pretherapeutic (99m)Tc MAA study and the post-therapeutic (90)Y Bremsstrahlung images were 4.77 ± 2.81 and 4.52 ± 2.5%, respectively. The coefficient of correlation (r) was 0.96. (99m)Tc MAA scintigraphy accurately predicts the HPS of (90)Y microspheres.

  3. Development of radiolabeled probes directed against sigma-1 receptors

    International Nuclear Information System (INIS)

    Ogawa, Kazuma; Masuda, Ryohei; Shiba, Kazuhiro

    2017-01-01

    It has been reported that sigma-1 receptors regulate the release of signaling substances in the central nervous systems and are related to various diseases, such as schizophrenia, stress disorders, dementia, amyotrophic lateral sclerosis (ALS), and cancer. If the quantification of the sigma-1 receptors is possible, the pathophysiology, the stage, and the early detection of the diseases could be understandable. Molecular imaging using Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT) and radioactive probes makes noninvasive quantification of the in vivo metabolism and function possible. Currently, only nuclear medicine diagnosis using PET or SPECT can quantify the sigma-1 receptors. Therefore, there is great expectation for the development of molecular probes to image the sigma-1 receptors specifically. In this paper, we introduce our research on the development of radiohalogen-labeled molecular probes directed against the sigma-1 receptors. (author)

  4. Imaging of Homeostatic, Neoplastic, and Injured Tissues by HA-Based Probes

    Science.gov (United States)

    Veiseh, Mandana; Breadner, Daniel; Ma, Jenny; Akentieva, Natalia; Savani, Rashmin C; Harrison, Rene; Mikilus, David; Collis, Lisa; Gustafson, Stefan; Lee, Ting-Yim; Koropatnick, James; Luyt, Leonard G.; Bissell, Mina J.; Turley, Eva A.

    2013-01-01

    An increase in hyaluronan (HA) synthesis, cellular uptake, and metabolism occurs during the remodeling of tissue microenvironments following injury and during disease processes such as cancer. We hypothesized that multimodality HA-based probes selectively target and detectably accumulate at sites of high HA metabolism, thus providing a flexible imaging strategy for monitoring disease and repair processes. Kinetic analyses confirmed favorable available serum levels of the probe following intravenous (i.v.) or subcutaneous (s.c.) injection. Nuclear (technetium-HA, 99mTc-HA, and iodine-HA, 125I-HA), optical (fluorescent Texas Red-HA, TR-HA), and magnetic resonance (gadolinium-HA, Gd-HA) probes imaged liver (99mTc-HA), breast cancer cells/xenografts (TR-HA, Gd-HA), and vascular injury (125I-HA, TR-HA). Targeting of HA probes to these sites appeared to result from selective HA receptor-dependent localization. Our results suggest that HA-based probes, which do not require polysaccharide backbone modification to achieve favorable half-life and distribution, can detect elevated HA metabolism in homeostatic, injured, and diseased tissues. PMID:22066590

  5. Process and device for extracting a probe carrier from the lower chamber of a vertical tubular heat exchanger

    International Nuclear Information System (INIS)

    Adamoski, Andrev.

    1980-01-01

    It is necessary to check the water tubes of vertical heat exchangers used in nuclear power stations, for it is essential that the water making up the primary fluid and contaminated by nuclear reactors should not enter the secondary fluid used for actuating a turbo-generator. This checking is performed by passing a Foucault current probe through each tube. A crack or hole in the tube or even just a reduction in the thickness of the tube produces a change in the output current of the probe [fr

  6. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff Mathiasen, Anne-Gitte

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  7. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff, Anne-Gitte

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  8. Development of a compact light weight DELRAD probe and its integration with UAV NETRA for aerial radiation surveillance

    International Nuclear Information System (INIS)

    Prasad, Mahaveer; Yadav, Ashok Kumar; Gupta, D.K.; Bhatnagar, Vivek; Singh, Chiman; Mishrilal

    2018-01-01

    The DEfence Laboratory RAdiation Detector - 'DELRAD' is an indigenously developed Hybrid Micro Circuit Module employing Si PIN diodes for detection of gamma radiation. Using this as a detector, the 'DELRAD Probe' has been designed and developed specifically for the UAV, NETRA for aerial surveillance of the nuclear affected areas. The critical requirement of very light weight radiation sensor as payload (<50gm) for the UAV NETRA is met by designing this Probe weighing approx. 40gm. The sensor is capable of measuring gamma radiation levels from 1mR/h to 1000R/h. The Probe has been tested, calibrated and integrated with the UAV NETRA. In addition to this, the radiation testing during flight of UAV NETRA integrated with DELRAD probe has also been carried out and results have been recorded. The work carried out proves the capability of Defence Laboratory, Jodhpur, (DRDO) in the area of 'Aerial Surveillance of Nuclear Radiation Affected Area' using Unmanned Aerial Vehicles (UAVs)

  9. Evolutionary use of nuclear electric propulsion

    International Nuclear Information System (INIS)

    Hack, K.J.; George, J.A.; Riehl, J.P.; Gilland, J.H.

    1990-01-01

    Evolving new propulsion technologies through a rational and conscious effort to minimize development costs and program risks while maximizing the performance benefits is intuitively practical. A phased approach to the evolution of nuclear electric propulsion from use on planetary probes, to lunar cargo vehicles, and finally to manned Mars missions with a concomitant growth in technology is considered. Technology levels and system component makeup are discussed for nuclear power systems and both ion and magnetoplasmadynamic thrusters. Mission scenarios are described, which include analysis of a probe to Pluto, a lunar cargo mission, Martian split, all-up, and quick-trip mission options. Evolutionary progression of the use of NEP in such missions is discussed. 26 refs

  10. Exact Bremsstrahlung and effective couplings

    Energy Technology Data Exchange (ETDEWEB)

    Mitev, Vladimir [Institut für Physik, WA THEP, Johannes Gutenberg-Universität Mainz,Staudingerweg 7, 55128 Mainz (Germany); Institut für Mathematik und Institut für Physik, Humboldt-Universität zu Berlin,IRIS Haus, Zum Großen Windkanal 6, 12489 Berlin (Germany); Pomoni, Elli [DESY Hamburg, Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Physics Division, National Technical University of Athens,15780 Zografou Campus, Athens (Greece)

    2016-06-13

    We calculate supersymmetric Wilson loops on the ellipsoid for a large class of N=2 SCFT using the localization formula of Hama and Hosomichi. From them we extract the radiation emitted by an accelerating heavy probe quark as well as the entanglement entropy following the recent works of Lewkowycz-Maldacena and Fiol-Gerchkovitz-Komargodski. Comparing our results with the N=4 SYM ones, we obtain interpolating functions f(g{sup 2}) such that a given N=2 SCFT observable is obtained by replacing in the corresponding N=4 SYM result the coupling constant by f(g{sup 2}). These “exact effective couplings” encode the finite, relative renormalization between the N=2 and the N=4 gluon propagator and they interpolate between the weak and the strong coupling. We discuss the range of their applicability.

  11. Deep inelastic scattering

    International Nuclear Information System (INIS)

    Zakharov, V.I.

    1977-01-01

    The present status of the quark-parton-gluon picture of deep inelastic scattering is reviewed. The general framework is mostly theoretical and covers investigations since 1970. Predictions of the parton model and of the asymptotically free field theories are compared with experimental data available. The valence quark approximation is concluded to be valid in most cases, but fails to account for the data on the total momentum transfer. On the basis of gluon corrections introduced to the parton model certain predictions concerning both the deep inelastic structure functions and form factors are made. The contributions of gluon exchanges and gluon bremsstrahlung are highlighted. Asymptotic freedom is concluded to be very attractive and provide qualitative explanation to some experimental observations (scaling violations, breaking of the Drell-Yan-West type relations). Lepton-nuclear scattering is pointed out to be helpful in probing the nature of nuclear forces and studying the space-time picture of the parton model

  12. Bremsstrahlung hard x-ray source driven by an electron beam from a self-modulated laser wakefield accelerator

    Science.gov (United States)

    Lemos, N.; Albert, F.; Shaw, J. L.; Papp, D.; Polanek, R.; King, P.; Milder, A. L.; Marsh, K. A.; Pak, A.; Pollock, B. B.; Hegelich, B. M.; Moody, J. D.; Park, J.; Tommasini, R.; Williams, G. J.; Chen, Hui; Joshi, C.

    2018-05-01

    An x-ray source generated by an electron beam produced using a Self-Modulated Laser Wakefield Accelerator (SM-LWFA) is explored for use in high energy density science facilities. By colliding the electron beam, with a maximum energy of 380 MeV, total charge of >10 nC and a divergence of 64 × 100 mrad, from a SM-LWFA driven by a 1 ps 120 J laser, into a high-Z foil, an x/gamma-ray source was generated. A broadband bremsstrahlung energy spectrum with temperatures ranging from 0.8 to 2 MeV was measured with an almost 2 orders of magnitude flux increase when compared with other schemes using LWFA. GEANT4 simulations were done to calculate the source size and divergence.

  13. Nuclear utility self-assessment as viewed by the corporate nuclear safety committee

    International Nuclear Information System (INIS)

    Corcoran, W.R.

    1992-01-01

    This paper discusses how corporate nuclear safety committees use the principles of self-assessment to enhance nuclear power plant safety performance. Corporate nuclear safety committees function to advise the senior nuclear power executive on matters affecting nuclear safety. These committees are required by the administrative controls section of the plant technical specifications which are part of the final safety analysis report and the operating license. Committee membership includes senior utility executives, executives from sister utilities, utility senior technical experts, and outside consultants. Current corporate nuclear safety committees often have a finely tuned intuitive feel for self-assessment that they use to probe the underlying opportunities for quality and safety enhancements. The questions prompted by the self-assessment orientation enable the utility line organization members to gain better perspectives on the characteristics of the organizational systems that they manage and work in

  14. Feasibility of a wireless gammar probe in radioguided surgery

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hye Min; Kim, Jeong Ho; Park, Chan Jong; Joo, Koan Sik [Dept. of Physics, University of Myongji, Seoul (Korea, Republic of)

    2016-04-15

    Nuclear medicine is divided into two major domains: diagnosis and therapy. Nuclear medicine diagnostic procedures are used for determining and evaluating the physiological, chemical, endocrinal, and metabolic conditions of organs or tissues. Tumors can be diagnosed based on the images provided by the associated machinery; after diagnosis, sometimes these tumors can be surgically removed. Currently, to help guide the surgeon to the exact location of the tumor site, the use of intraoperative probes has steadily gained popularity. These probes allow the physician to locate the tumor on the basis of the higher uptake of the preoperatively injected radio pharmaceutical within the site, as compared to the surrounding tissue. Direct detection offers very good energy resolution, but the detection efficiency is low; on the other hand, indirect detection presents high efficiency and low energy resolution. For this reason, the use of both detectors is recommended for obtaining an accurate localization of the diagnostic and therapeutic fields. In the literature, there are several works that aim to develop a suitable probe that presents such characteristics (i.e., good resolution, high detection efficiency, as well as the capacity for miniaturization). In this study, a wireless gamma probe is designed for the detection of tumors of the tissue surface using a silicon photomultiplier (SiPM) and a cerium-doped gadolinium aluminum gallium garnet (Ce:GAGG) scintillator. Our experiments demonstrate the feasibility of wireless diagnostics, as well as the suitable energy resolution and spatial resolution. The system developed based on the results of this study is expected to perform intraoperative or diagnostic evaluations of residual lesions (or the absence thereof) and its quantitative distribution in the affected area, thus contributing to wireless diagnostics and screening systems.

  15. Nuclear moments as a probe of electronic structure in material, exotic nuclear structure and fundamental symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Matsuta, K., E-mail: matsuta@vg.phys.sci.osaka-u.ac.jp; Minamisono, T.; Mihara, M.; Fukuda, M. [Osaka Univ., Dept. of Physics (Japan); Zhu, Shengyun [CIAE (China); Masuda, Y. [High Energy Accelerator Research Organization (KEK) (Japan); Hatanaka, K. [Osaka Univ., RCNP (Japan); Yuan Daqing; Zheng Yongnan; Zuo Yi; Fang Ping; Zhou Dongmei [CIAE (China); Ohtsubo, T. [Niigata Univ., Dept. of Physics (Japan); Izumikawa, T. [Niigata Univ., RI Center (Japan); Momota, S. [Kochi Univ. of Technology (Japan); Nishimura, D. [Tokyo Univ. of Science (Japan); Matsumiya, R. [Osaka Univ., RCNP (Japan); Kitagawa, A.; Sato, S.; Kanazawa, M. [Nat. Inst. Radiological Sciences (Japan); Collaboration: Osaka-CIAE-NIRS-Niigata-Kochi-LBL Collaboration; and others

    2013-05-15

    We report our studies in various fields of Physics through nuclear moments utilizing the {beta}-NMR technique, including material sciences, nuclear structures and fundamental symmetries. Especially, we focus on the recent progress in the studies on the electronic structure in Pt through Knight shifts of various impurities, lattice locations of impurities, electric field gradients, the analysis of nuclear spin in terms of its components, anomaly in the spin expectation value for {sup 9}C-{sup 9}Li mirror pair, the G-parity conservation law, and the Ramsey resonance on UCN for future neutron EDM measurements.

  16. Calculation of energy and angular distributions of the bremsstrahlung of 10 MeV electrons bombarding a thick tungsten target

    International Nuclear Information System (INIS)

    Tsovbun, V.I.

    1977-01-01

    Computer calculations have been performed to extend the data available on energy and angular distribution of the 10 MeV electron bremsrahlung into a higher angle region. The ETRAN-16D program developed by R.G.Berger for calculation of electron-photon cascades passing through matter using computers IBM-360 and UNIVAC-1108 was modified to operate with the CDC-6500 computer. A brief summary of the program is provided. An angular distribution of the bremsstrahlung dose absorbed in the air has been also calculated. The results extended into the 90-180 deg region can be used to calculate the biological shield of electron accelerators

  17. Antiprotonic Radioactive Atom for Nuclear Structure Studies

    International Nuclear Information System (INIS)

    Wada, M.; Yamazaki, Y.

    2005-01-01

    A future experiment to synthesize antiprotonic radioactive nuclear ions is proposed for nuclear structure studies. Antiprotonic radioactive nuclear atom can be synthesized in a nested Penning trap where a cloud of antiprotons is prestored and slow radioactive nuclear ions are bunch-injected into the trap. By observing of the ratio of π+ and π- produced in the annihilation process, we can deduce the different abundance of protons and neutrons at the surface of the nuclei. The proposed method would provide a unique probe for investigating the nuclear structure of unstable nuclei

  18. Development and implementation of UT procedures for nuclear and other applications using TRL phased array probes

    International Nuclear Information System (INIS)

    Chardome, V.; Delaide, M.; Cermak, J.; Cruysweegs, E.; Plateau, M.

    2006-01-01

    In the past, Vincotte developed, qualified and applied various UT procedures for the automated in-service inspection of austenitic and dissimilar metal welds, using conventional ultrasonic probes. In a process of continuous improvement, Vincotte is upgrading these existing procedures by applying low frequency TRL phased array probes. This presentation situates this recent innovation within the phased array history of Vincotte. Particular attention will be paid to these newest phased array developments, in terms of probe development, angled beam generation and scanning patterns. (orig.)

  19. Neutron and gamma probes: Their use in agronomy. Second edition

    International Nuclear Information System (INIS)

    2003-01-01

    Water is an essential requirement for life on the planet. It is often the single most limiting factor in crop and livestock production. Water is a scarce resource in many urban and rural environments worldwide. According to the FAO, the global demand for fresh water is doubling every 21 years. The quality of the finite water supplies is also under threat from industrial, agricultural and domestic sources of pollution. The majority of crops are grown under rain-fed conditions and adequate water supply is the main factor limiting crop production in semi-arid and sub-humid regions. On the other hand, currently 20% of the world's arable land is under irrigation providing 35 to 40% of all agricultural production. Irrigation mismanagement poses a serious threat to the environment through groundwater pollution and salinization. It is therefore, essential that water resources be used efficiently by regular monitoring of soil-water status in the unsaturated zone. The neutron depth probe, a nuclear-based technique, is utilized worldwide for this purpose. The neutron moisture gauge, since its introduction some 40 years ago, can now be considered a routine method in soil water studies. Many developments have since been introduced, in particular electronic components, which have significantly improved performance and expanded applications. Although the neutron scattering method is routinely utilised in many developed countries, its use is still limited in developing countries due to several factors. Neutron depth probes contain radioactive sources, which will present health and environmental hazards if a probe is improperly used, stored or disposed of. National and international legislation and regulations must be complied with. The strategic objective of the sub-program Soil and Water Management and Crop Nutrition of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture is to develop and promote the adoption of nuclear-based technologies for optimising soil

  20. Intermediate energy nuclear fission

    International Nuclear Information System (INIS)

    Hylten, G.

    1982-01-01

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)