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Sample records for bremsstrahlung

  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. Polarization bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Korol, Andrey V.; Solov' yov, Andrey V. [Frankfurt Univ. (Germany). Frankfurt Inst. for Advanced Studies

    2014-03-01

    Authored by leading experts in the field. Self-contained introduction to the subject matter. Suitable as graduate text on the topic. 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 for e.g. plasma diagnostics as well as astrophysical and medical applications (such as radiation therapy). This book primarily addresses graduate students and researchers with a background in atomic, molecular, optical or plasma physics, but will also be of benefit to anyone wishing to enter the field.

  3. 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.

  4. Simulation of Bremsstrahlung production

    Energy Technology Data Exchange (ETDEWEB)

    Patau, J.P.; Malbert, M.; Terrissol, M. (Centre de Physique Atomique, Toulouse (France))

    1981-10-01

    Electron slowing down and related phenomena are often greatly affected by bremsstrahlung production. Each creation of photon is individually simulated on the basis of a cross-section pack advised by Koch and Motz with corrections in the high energy frequency limit region. An accurate and fast sampling method is described. Its applicability covers a range between 50 keV and 80 MeV for target atoms whose atomic number is from 5 up to 90.

  5. Coherence effects in nuclear bremsstrahlung

    NARCIS (Netherlands)

    Lohner, H

    The production of nuclear bremsstrahlung (Egamma > 30 MeV) has been studied in heavy-ion collisions, as well as proton and alpha-particle collisions with nuclei. In heavy-ion reactions the measured photon spectra show an exponential shape dominated by the incoherent sum of photons produced in

  6. Internal bremsstrahlung of strongly interacting charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Kurgalin, S. D. [Voronezh State University (Russian Federation); Tchuvil’sky, Yu. M., E-mail: tchuvl@nucl-th.sinp.msu.ru [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Churakova, T. A. [Voronezh State University (Russian Federation)

    2016-11-15

    A universal theoretical model intended for calculating internal-bremsstrahlung spectra is proposed. In this model, which can be applied to describing nuclear decays of various type (such as alpha decay, cluster decay, and proton emission), use is made of realistic nucleus–nucleus potentials. Theoretical internal-bremsstrahlung spectra were obtained for the alpha decay of the {sup 214}Po nucleus, as well as for the decay of the {sup 222}Ra nucleus via the emission of a {sup 14}C cluster and for the decay of the {sup 113}Cs nucleus via proton emission, and the properties of these spectra were studied. The contributions of various regions (internal, subbarrier, and external) to the internal-bremsstrahlung amplitude were analyzed in detail. It is shown that the contribution of the internal region to the amplitude for internal bremsstrahlung generated in nuclear decay via proton emission is quite large, but that this is not so for alpha decay and decay via cluster emission. Thus, a process in which strong interaction of nuclear particles affects the internal-bremsstrahlung spectrum if found.

  7. 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...

  8. Bremsstrahlung sum rule and nuclear charge distribution

    Energy Technology Data Exchange (ETDEWEB)

    Dellafiore, A. (Florence Univ. (Italy). Ist. di Fisica Teorica; Istituto Nazionale di Fisica Nucleare, Florence (Italy)); Lipparini, E. (Trento Univ. (Italy). Dipartimento di Fisica)

    1982-11-01

    We derive a model-independent relation between the nuclear charge radius Rsub(c), the bremsstrahlung-weighted photoabsorption sum rule sigmasub(-)/sub 1/ and the mean proton distance. Such a relation allows the mean proton distance to be determined from available experimental data. We also discuss the Foldy sum rule in the light of our result.

  9. Inverse Bremsstrahlung in Astrophysical Plasmas: The Absorption ...

    Indian Academy of Sciences (India)

    The electron–ion inverse Bremsstrahlung is considered here as a factor of the influence on the opacity of the different stellar atmospheres and other astrophysical plasmas. It is shown that this process can be successfully described in the frames of cut-off Coulomb potential model within the regions of the electron densities ...

  10. Studies of total bremsstrahlung spectra in the oxides of lanthanides

    Science.gov (United States)

    Singh, Amrit; Singh, Tajinder; Dhaliwal, A. S.

    2017-12-01

    Total bremsstrahlung spectral photon distribution generated in thick targets of oxides of lanthanides (Pr6O11, Gd2O3, Tb4O7 and Er2O3) by 89Sr beta particles has been investigated in the photon energy region 1-100 keV. The experimental results are compared with the theory describing ordinary bremsstrahlung and the theory which includes polarization bremsstrahlung into ordinary bremsstrahlung in stripped approximation. It has been found that contribution of polarization bremsstrahlung into total bremsstrahlung in a target is limited to a low energy region only and also varies with the effective atomic number (Zeff) of target material. Further, it has been found that the suppression of polarization bremsstrahlung has been observed due to the presence of large fraction of low Z element oxygen in the compounds.

  11. 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.

  12. Deuteron bremsstrahlung-weighted photonuclear sum rule

    Energy Technology Data Exchange (ETDEWEB)

    Bohigas, O.; Lipparini, E.

    1987-11-01

    The various contributions to the deuteron bremsstrahlung-weighted photonuclear sum rule sigma/sub -1/ are analyzed. It is shown that the unretarded normal L = 1 sum rule is model independent and that retardation, higher multipoles, and interaction effects are negligible. An accurate estimation of sigma/sub -1/ is provided by the knowledge of the charge deuteron radius and of the spin gyromagnetic factors of the proton and of the neutron.

  13. Inverse Bremsstrahlung in Astrophysical Plasmas: The Absorption ...

    Indian Academy of Sciences (India)

    (λ, T ; Ne,Ni) = k q.c. i.b.. (λ, T ; Ne,Ni) · Gi.b.(λ, T ),. (2) where Gi.b.(λ, T ) is the sought Gaunt factor. The determination of such averaged. Gaunt factor as a function of λ and T was the object of investigation in majority of the previous papers devoted to the inverse Bremsstrahlung process. This is illustrated in Figure 1, where ...

  14. Investigation of Bremsstrahlung spectra of 6 MV medical linear accelerator

    CERN Document Server

    Zhang Song Bai; Bao Shang Lian; Zhao Hong Bin; Han Shu Kui

    2003-01-01

    The energy spectra of the Bremsstrahlung X-rays from the 6 MV medical linear accelerator are measured by attenuation analysis of the transmission data. An universal Monte-Carlo program EGS4 is also used to calculate the Bremsstrahlung spectra of the 6 MV medical linear accelerator. The measurement results are in good agreement with the calculation results

  15. Two-particle correlation via Bremsstrahlung

    Directory of Open Access Journals (Sweden)

    Cho Soyeon

    2017-01-01

    Full Text Available Ridge is the well-known structure in two-particle angular correlations at highenergy heavy-ion collisions. This structure is physically understood through elliptic and higher-order flows at nucleus-nucleus collisions. This behavior is also found in small systems, such as proton-proton collisions, recently. However, Ridge structure in small system is hard to be understood using hydrodynamics, since small systems are not dense enough to produce the Quark-Gluon plasma. Thus, we try to describe this phenomena through kinematic interaction between jets and medium partons. In high-energy heavy-ion collision, the energetic particles called jets go out in specific direction and lose their energy while passing through the medium. During such process, photons/gluons are emitted from interaction between jets and medium partons. We concentrate on energy loss via photon radiations, known as Bremsstrahlung. Recently, two symmetric double scattering processes between jet particle and medium parton are reported to be able to produce certain constructive interference, which gives collective motion and medium partons are aligned along incoming jet particles. We conjecture that similar behavior might happen in Bremsstrahlung processes, and therefore we consider the two symmetric diagrams of photon emission and medium parton scattering. We expect these two amplitudes to give constructive interference leading to the collective motion of medium. We check the correlation between emitted photon and final jet, and those between medium parton and final jet for high-energy jet. To describe parton momentum distribution in medium, we use the Maxwell-Boltzmann distribution. We discover collective motion in both angular correlations. We also check the tendency of the angular correlation for two particles according to the incident angle of jet particle, energy of emitted photon and temperature of systems, respectively. We can conclude that collective motion is able to be

  16. Angular distributions of bremsstrahlung photons from ECR plasma

    Science.gov (United States)

    Kumwenda, M. J.; Ahn, J. K.; Lee, J. W.; Lugendo, I. J.; Kim, S. J.; Park, J. Y.; Won, M. S.

    2017-12-01

    High-energy bremsstrahlung photon emission beyond a critical energy from electron cyclotron resonance (ECR) heating has long attracted much attention, and its nature has yet been unsolved. We have measured bremsstrahlung photons from the 28-GHz ECR ion source at Busan Center of Korean Basic Science Institute. The gamma-ray detection system consists of three NaI(Tl) scintillation detectors placed 62 cm radially from the beam axis and a NaI(Tl) scintillation detector at the extraction port for monitoring the photon intensity along the beam axis. Bremsstrahlung photon energy spectra were measured at nine azimuthal angles at the RF power of 1 kW. Azimuthal angular distributions of bremsstrahlung photons were found to be in coincidence with the structure the ECR ion source and the shape of ECR plasma.

  17. Bremsstrahlung background in inelastic electron-nucleus collisions

    Science.gov (United States)

    Jakubassa-Amundsen, D. H.; Krugmann, A.

    2017-04-01

    Bremsstrahlung emission by relativistic electrons in collisions with medium heavy spin-zero nuclei is calculated within the plane-wave Born approximation. Coulomb distortion is estimated by a comparison with the Dirac partial-wave theory at energies up to 20 MeV. When integrated over the photon emission angle, the bremsstrahlung spectra help to explain the background of the nuclear excitation spectra in 150Nd (e,e\\prime ) reactions which were recently measured on an absolute scale.

  18. 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.

  19. Towards the exact Bremsstrahlung function of ABJM theory

    Science.gov (United States)

    Bianchi, Marco S.; Griguolo, Luca; Mauri, Andrea; Penati, Silvia; Preti, Michelangelo; Seminara, Domenico

    2017-08-01

    We present the three-loop calculation of the Bremsstrahlung function associated to the 1/2-BPS cusp in ABJM theory, including color subleading corrections. Using the BPS condition we reduce the computation to that of a cusp with vanishing angle. We work within the framework of heavy quark effective theory (HQET) that further simplifies the analytic evaluation of the relevant cusp anomalous dimension in the near-BPS limit. The result passes nontrivial tests, such as exponentiation, and is in agreement with the conjecture made in [1] for the exact expression of the Bremsstrahlung function, based on the relation with fermionic latitude Wilson loops.

  20. Jovian bremsstrahlung X-rays - A Ulysses prediction

    Science.gov (United States)

    Waite, J. H., Jr.; Boice, D. C.; Hurley, K. C.; Stern, S. A.; Sommer, M.

    1992-01-01

    Modeling results reported here show that precipitating auroral electrons with sufficient energy to be consistent with the Voyager UVS observations produce bremsstrahlung X-rays with sufficient energy and intensity to be detected by the Solar Flare X-ray and Cosmic-Ray-Burst Instrument on board the Ulysses spacecraft. The detection of such bremsstrahlung X-rays at Jupiter would provide strong evidence for the electron-precipitation mechanism, although it does not rule out the possibility of some heavy ion involvement, and thus makes a significant contribution toward solving the mystery of the Jovian aurora.

  1. Observation of the Muon Inner Bremsstrahlung at LEP1

    CERN Document Server

    Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, U; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, P; Ballestrero, A; Bambade, P; Barbier, R; Bardin, D; Barker, G J; Baroncelli, A; Battaglia, M; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N; Benvenuti, A; Bérat, C; Berggren, M; Bertrand, D; Besançon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Buschbeck, B; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F; Chapkin, M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L; Di Ciaccio, L; Di Simone, A; Doroba, K; Drees, J; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J; Gandelman, M; García, C; Gavillet, P; Gazis, E; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Kokkinias, P; Leinonen, L; Katsoufis, E; Kernel, G; Kersevan, B P; Krumshtein, Z; Lesiak, T; Kerzel, U; Liebig, W; King, B T; Lamsa, J; Liko, D; Kjaer, N J; Leder, G; Kluit, P; Kourkoumelis, C; Leitner, R; Kuznetsov, O; Kucharczyk, M; Ledroit, F; Lopes, J H; Lemonne, J; Lepeltier, V; Lipniacka, A; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, G; Myklebust, T; Paganoni, M; Nassiakou, M; Paiano, S; Navarria, F; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Ouraou, A; Parkes, C; Oblakowska-Mucha, A; Oyanguren, A; Obraztsov, V F; Olshevski, A; Palacios, J P; Onofre, A; Palka, H; Orava, R; Österberg, K; Pape, L; Papadopoulou, T D; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Pozdnyakov, V; Pukhaeva, N; Pullia, A; Rames, J; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Roudeau, P; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Sander, C; Savoy-Navarro, A; Schwickerath, U; Sekulin, R; Siebel, M; Sisakian, A; Smadja, G; Smirnova, O; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Tegenfeldt, F; Timmermans, J; Tkatchev, L; Tobin, M; Todorovova, S; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Remortel, N; Van Vulpen, I; Vegni, G; Veloso, F; Venus, W; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O; Zalewska-Bak, A; Zalewski, P; Zavrtanik, D; Zhuravlov, V; Zimin, N I; Zintchenko, A; Zupan, M

    2008-01-01

    Muon bremsstrahlung photons converted in front of the DELPHI main tracker (TPC) in dimuon events at LEP1 were studied in two photon kinematic ranges: 0.2 < E_gamma <= 1 GeV and transverse momentum with respect to the parent muon p_T < 40 MeV/c, and 1 < E_gamma <= 10 GeV and p_T < 80 MeV/c . A good agreement of the observed photon rate with predictions from QED for the muon inner bremsstrahlung was found, contrary to the anomalous soft photon excess that has been observed recently in hadronic Z^0 decays. The obtained ratios of the observed signal to the predicted level of the muon bremsstrahlung are 1.06 +/- 0.12 +/- 0.07 in the photon energy range 0.2 < E_gamma <= 1 GeV and 1.04 +/- 0.09 +/- 0.12 in the photon energy range 1 < E_gamma <= 10 GeV. The bremsstrahlung dead cone is observed for the first time in the direct photon production at LEP.

  2. Monte Carlo Generation of the 2BN Bremsstrahlung Distribution

    CERN Document Server

    Peralta, L; Trindade, A

    2003-01-01

    The 2BN bremsstrahlung cross-section is a well-adapted distribution to describe the radiative processes at low electron kinetic energy (Ek<500 keV). In this work a method to implement this distribution in a Monte Carlo generator is developed.

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

    Indian Academy of Sciences (India)

    ... agreement between the experimental data and the MC calculations is found for all the four targets within the experimental error of 16%. Furthermore, the ratios of DDCS of bremsstrahlung photons emitted from Ag, W and Pt with those from Ti as a function of photon energy are examined with a relatively lower uncertainty of ...

  4. On the bremsstrahlung background correction to the high-energy ...

    Indian Academy of Sciences (India)

    A methodology for bremsstrahlung (BS) background correction to extract a true Compton profile in high-energy Compton scattering experiments is presented. The BS background profiles for Hg, computed within the Born approximation, are estimated for different values of incident energy. It is seen for the first time that the BS ...

  5. Effects of relativity in proton-proton bremsstrahlung

    NARCIS (Netherlands)

    Martinus, G.H.; Scholten, O.; Tjon, J.A.

    1997-01-01

    We investigate the influence of negative-energy states in proton-proton bremsstrahlung in a fully relativistic framework using the T matrix of Fleischer and Tjon. The contribution from negative-energy states in the single-scattering diagrams is shown to be large, indicating that relativistic effects

  6. Proton-proton virtual bremsstrahlung in a relativistic covariant model

    NARCIS (Netherlands)

    Martinus, GH; Scholten, O; Tjon, J

    1999-01-01

    Lepton-pair production (virtual bremsstrahlung) in proton-proton scattering is investigated using a relativistic covariant model. The effects of negative-energy slates and two-body currents are studied. These are shown to have large effects in some particular structure functions, even at the

  7. On the bremsstrahlung background correction to the high-energy ...

    Indian Academy of Sciences (India)

    Abstract. A methodology for bremsstrahlung (BS) background correction to extract a true Compton profile in high-energy Compton scattering experiments is presented. The. BS background profiles for Hg, computed within the Born approximation, are estimated for different values of incident energy. It is seen for the first time ...

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

    Indian Academy of Sciences (India)

    In this work, the Weibel instability due to inverse bremsstrahlung absorption in laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by Weibel instability with the laser wave field is explicitly showed. The main result obtained in this work is that the inclusion ...

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

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... 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) ...

  10. Coherence effects and neutrino pair bremsstrahlung in neutron stars

    NARCIS (Netherlands)

    Sedrakian, A; Dieperink, A

    1999-01-01

    We calculate the rate of energy radiation by bremsstrahlung of neutrino pairs by baryons in neutron stars employing a transport model where neutrinos couple to baryons with spectral width. The: coherence effects, which are included by computing the self energies with fully dressed propagators, lead

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

    Indian Academy of Sciences (India)

    2016-11-04

    Nov 4, 2016 ... Abstract. In this work, the Weibel instability due to inverse bremsstrahlung absorption in laser fusion plasma has been investigated. The stabilization effect due to the coupling of the self-generated magnetic field by Weibel instability with the laser wave field is explicitly showed. The main result obtained in ...

  12. Time evolution of bremsstrahlung and ion production of an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, Ollie [Los Alamos National Laboratory; Ropponen, Tommi [UNIV OF JYVASKYLA; Jones, Peter [UNIV OF JYVASKYLA; Peura, Pauli [UNIV OF JYVASKYLA

    2008-01-01

    Bremsstrahlung radiation measurement is one of the most commonly used plasma diagnostics methods. Most of the bremsstrahlung measurements with electron cyclotron resonance (ECR) ion sources have been performed in continuous operation mode yielding information only on the steady state bremsstrahlung emission. This article describes the results of bremsstrahlung and ion current measurement with the JYFL 14 GHz ECRIS operated in pulsed mode. The experiments reveal information about the bremsstrahlung radiation in plasma conditions before reaching the equilibrium. The time scale of bremsstrahlung production is compared to ion production time scale for different charge states. The bremsstrahlung data is presented with 2 millisecond time intervals as a function of neutral gas pressure and microwave power. Data from hundreds of microwave pulses is combined in order to have a sufficient amount of events at each time step. The relevant plasma physics phenomena during both, the leading and the trailing edge of the RF pulse, are discussed.

  13. Bremsstrahlung from an Equilibrating Quark-Gluon Plasma

    CERN Document Server

    Mustafa, Munshi G.; Mustafa, Munshi G.; Thoma, Markus H.

    2000-01-01

    The photon production rate from a chemically equilibrating quark-gluon plasma likely to be produced at RHIC (BNL) and LHC (CERN) energies is computed taking into account bremsstrahlung. The plasma is assumed to be in local thermal equilibrium, but with a phase space distribution that deviates from the Fermi or Bose distribution by space-time dependent factors (fugacities). The photon spectrum is obtained by integrating the photon rate over the space-time history of the plasma, adopting a boost invariant cylindrically symmetric transverse expansion of the system with different nuclear profile functions. Initial conditions obtained from a self-screened parton cascade calculation and, for comparison, from the HIJING model are used. Compared to the equilibrium case a suppression of the photon yield by one to three orders of magnitude is observed. Furthermore the photon production due to bremsstrahlung from the chemically nonequilibrated plasma dominates over the emission from Compton scattering and quark-antiquar...

  14. Bremsstrahlung and fluorescence in PMTs causing fast afterpulses

    Energy Technology Data Exchange (ETDEWEB)

    Tippmann, Marc; Knoetig, Max; Appel, Simon; Beischler, German; Kaindl, Jill; Lewke, Timo; Meindl, Quirin; Moellenberg, Randolph; Oberauer, Lothar; Pfahler, Patrick; Prade, Ludwig; Stempfle, Tobias; Winter, Juergen; Zimmer, Vincenz [Technische Universitaet Muenchen, Physik Department E15, James Franck Strasse, 85748 Garching (Germany); Collaboration: AGUNA-LENA working group

    2013-07-01

    LENA (Low Energy Neutrino Astronomy) is a next-generation liquid-scintillator neutrino detector with 50kt target mass. The broad spectrum of physics goals ranging from the sub-MeV to the GeV regime sets high demands on the photosensors. Currently, photomultipliers (PMTs) are the sensor of choice. However, besides detecting photons, they also emit light through bremsstrahlung or fluorescence induced by the electron avalanche in the dynode chain, which can produce further pulses in the same PMT or adjacent sensors. In order to study these effects and their connection to afterpulses occurring in the PMT, measurements of light emission and fast afterpulses have been carried through in collaboration with the CTA project. Both bremsstrahlung and fluorescence have been observed, with the first also being the origin of a type of fast afterpulses.

  15. Feasibility studies of the diffractive bremsstrahlung measurement at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Chwastowski, Janusz J.; Czekierda, Sabina; Staszewski, Rafal; Turnau, Jacek; Trzebinski, Maciej [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow (Poland); Kycia, Radoslaw [Cracow University of Technology, Faculty of Physics, Mathematics and Computer Science, Cracow (Poland)

    2016-06-15

    Feasibility studies of an observation of the exclusive diffractive bremsstrahlung in proton-proton scattering at the centre of mass energy 13 TeV at the LHC are reported. These studies aim at the dedicated data taking periods with low instantaneous luminosity delivered by the LHC where the pile-up interactions can be neglected. A simplified approach to the photon and the scattered proton energy reconstruction is used. The background influence is discussed. (orig.)

  16. Monte Carlo simulation of bremsstrahlung produced at SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Yoshihiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-03-01

    Beam lines of SPring-8 storage ring is now under operation after 1997. An energy range necessary for safety analysis is from some keV synchrotrons radiation to 8 GeV electrons, photons and photoneutrons, some of them have directional distribution. Simulations which includes empirical data are needed in some cases, these are: (1) gas bremsstrahlung radiation produced by the interaction between storage electrons and residual gases, (2) high energy photon behaviors caused by inverse-compton scattering, (3) neutrons produced by photonuclear reaction. A leakage flux caused by ground-shine of synchrotrons radiation is also estimated by simulation. Usually the beam line is set up on the extrapolated position of the straight line of the storage ring. In this case, gas bremsstrahlung from the storage ring is not negligible at the beam line. The Monte Carlo code (EGS4) on electromagnetic cascade interaction is used for estimation. Accuracy of the result is discussed with availability of assumptions including radial distribution. SPring-8 has the beam line in which high energy photons are produced by laser-electron interaction. In this case a photon has an energy of about 3.5 GeV. Local shielding for this gamma radiation is one of the key issues in the beam line design. The EGS4 code is used to simulate the effective shielding structure. The EGS4 code is also used to obtain track length distribution for gas bremsstrahlung photon to impinge the lead target. Safety analysis is made by the MCNP4b code. The wiggler and/or undulator installed in the storage ring produce complicated radiation spectrum. Computer codes (STAC8, ITS3.0, EGS4) are used to analyze photon transport. In this case, attenuation is very large, and time consuming calculation is needed. (Y. Tanaka)

  17. Polarization Bremsstrahlung on Atoms, Plasmas, Nanostructures and Solids

    CERN Document Server

    Astapenko, Valeriy

    2013-01-01

    The book is devoted to the modern theory and experimental manifestation of Polarization Bremsstrahlung (PB) which arises due to scattering of charged particles from various targets: atoms, nanostructures (including atomic clusters, nanoparticle in dielectric matrix, fullerens, graphene-like two-dimensional atomic structure) and in condensed matter (monocrystals, polycrystals, partially ordered crystals and amorphous matter) The present book addresses mainly researchers interested in the radiative processes during the interaction between fast particles and matter. It also will be useful for post-graduate students specializing in radiation physics and related fields.

  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. 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.

  20. Low-energy theorems for virtual nucleon-nucleon bremsstrahlung; Formalism and results

    NARCIS (Netherlands)

    Korchin, AY; Scholten, O; VanNeck, D

    1996-01-01

    We present results for cross sections and response functions in virtual bremsstrahlung induced by nucleon-nucleon collisions NN --> NN + e(+)e(-), based on two different low-energy theorems, The first low-energy theorem is a generalization of Low's theorem for real-photon bremsstrahlung. The second

  1. Measurement of absorbed dose by 7-GeV bremsstrahlung in a PMMA phantom

    CERN Document Server

    Job, P K; Semones, E

    1999-01-01

    High-energy electron storage rings generate energetic bremsstrahlung photons through radiative interaction of the particle beam with the residual gas molecules and other components inside the storage ring. At synchrotron radiation facilities, where beamlines are channeled out of the storage ring, a continuous bremsstrahlung spectrum, with a maximum energy of the stored particle beam, will be present. At the advanced photon source (APS), where the stored beam energy is 7 GeV, bremsstrahlung generated in the straight sections of the insertion device beamlines, which are a total of 15.38 m in length, can be significant. The contribution from each bremsstrahlung interaction adds up to produce a narrow mono-directional bremsstrahlung beam that comes down through the insertion device beamlines. The resulting absorbed dose distributions by this radiation in a 300 mmx300 mmx300 mm tissue substitute cube phantom were measured with LiF:Mg,Ti (TLD-700) thermoluminescent dosemeters. The normalized absorbed dose, in a cro...

  2. 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.

  3. Internal bremsstrahlung endpoint energy of {sup 54}Mn

    Energy Technology Data Exchange (ETDEWEB)

    Hindi, M. M. [Physics Department, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Larimer, R.-M. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Norman, E. B. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Rech, G. A. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2000-05-01

    For {sup 54}Mn there is a discrepancy between the Q{sub EC} obtained from the endpoint energy of the internal bremsstrahlung (IB) spectrum which accompanies the electron capture decay (Q{sub EC}=1353{+-}8 keV) and that obtained from the accepted mass differences (Q{sub EC}=1377{+-}1 keV). This Q value is needed to deduce the partial-half life of the astrophysically interesting {beta}{sup -} decay of {sup 54}Mn from the recently measured {beta}{sup +} partial half-life. To resolve this discrepancy, we have remeasured the endpoint energy of the IB spectrum, by recording coincidences between the IB and the 835-keV {gamma} ray, both detected in Compton-suppressed Ge detectors. The Q{sub EC} we deduce is 1379{+-}8 keV, in agreement with the accepted mass differences. (c) 2000 The American Physical Society.

  4. The double copy: Bremsstrahlung and accelerating black holes

    Energy Technology Data Exchange (ETDEWEB)

    Luna, Andrés [School of Physics and Astronomy, University of Glasgow,Glasgow G12 8QQ, Scotland (United Kingdom); Monteiro, Ricardo [Theoretical Physics Department, CERN,Geneva (Switzerland); Nicholson, Isobel [Higgs Centre for Theoretical Physics, School of Physics and Astronomy,The University of Edinburgh,Edinburgh EH9 3JZ, Scotland (United Kingdom); O’Connell, Donal [Higgs Centre for Theoretical Physics, School of Physics and Astronomy,The University of Edinburgh,Edinburgh EH9 3JZ, Scotland (United Kingdom); Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106-4030 (United States); White, Chris D. [School of Physics and Astronomy, University of Glasgow,Glasgow G12 8QQ, Scotland (United Kingdom)

    2016-06-06

    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.

  5. A Bremsstrahlung spectrometer using k-edge and differential filters with image plate dosimeters.

    Science.gov (United States)

    Chen, C D; King, J A; Key, M H; Akli, K U; Beg, F N; Chen, H; Freeman, R R; Link, A; Mackinnon, A J; MacPhee, A G; Patel, P K; Porkolab, M; Stephens, R B; Van Woerkom, L D

    2008-10-01

    A Bremsstrahlung spectrometer using k-edge and differential filtering has been used with image plate dosimeters to measure the x-ray fluence from short-pulse laser/target interactions. An electron spectrometer in front of the Bremsstrahlung spectrometer deflects electrons from the x-ray line of sight and simultaneously measures the electron spectrum. The response functions were modeled with the Monte Carlo code INTEGRATED TIGER SERIES 3.0 and the dosimeters calibrated with radioactive sources. An electron distribution with a slope temperature of 1.3 MeV is inferred from the Bremsstrahlung spectra.

  6. A Bremsstrahlung Spectrometer using k-edge and Differential Filters with Image plate dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C; Mackinnon, A; Beg, F; Chen, H; Key, M; King, J A; Link, A; MacPhee, A; Patel, P; Porkolab, M; Stephens, R; VanWoerkom, L; Akli, K; Freeman, R

    2008-05-02

    A Bremsstrahlung spectrometer using k-edge and differential filtering has been used with Image Plate dosimeters to measure the x-ray fluence from short-pulse laser/target interactions. An electron spectrometer in front of the Bremsstrahlung spectrometer deflects electrons from the x-ray line of sight and simultaneously measures the electron spectrum. The response functions were modeled with the Monte Carlo code Integrated Tiger Series 3.0 and the dosimeters calibrated with radioactive sources. Electron distributions with slope temperatures in the MeV range are inferred from the Bremsstrahlung spectra.

  7. 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.

  8. Generation of bremsstrahlung during multiple passes of accelerated electrons through a thin target in a betatron

    Science.gov (United States)

    Bespalov, V. I.; Kashkovsky, V. V.; Chakhlov, V. L.

    2003-01-01

    In the present work a method of bremsstrahlung generation in a betatron during multiple passes of the accelerated electrons through a thin target-converter is explored with the help of statistical modeling. The results are obtained on a basis of experimentally measured field distributions for the betatrons: MB-6 and B-35. The data of electron orbit dynamics and characteristics of bremsstrahlung field are given depending on parameters of the electron's dumping onto the target and sizes of the target.

  9. Effects of Soft-Core Potentials and Coulombic Potentials on Bremsstrahlung Radiation during Laser Matter Interaction

    Science.gov (United States)

    Pandit, Rishi; Sentoku, Yasuhiko; Sawada, Hiroshi; Ramunno, Lora; Ackad, Edward

    2017-10-01

    An intense, short laser pulse incident on rare-gas clusters can produce nano-plasmas containing energetic electrons. As these electrons undergo scattering, both from 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 potential. A new scaling for the radiation cross-section and Emissivity via bremsstrahlung are derived for soft-core potential which depends on the potential depth, used to avoid coulomb singularity and for coulombic potential and implemented in a particle in cell code (PICLS). The radiation cross-section and emissivity via bremsstrahlung is found to increase rapidly with increases in potential depth up to 100 eV and then becomes mostly saturated for larger depths of a soft-core potential. For both cases, the radiation cross-section and emissivity of Bremsstrahlung increases with increases in laser wavelength. The bremsstrahlung emission may provide a broadband light source for diagnostics. This work was supported by Air Force Office of Scientific Research under AFOSR Award No. FA9550-14-1-0247.

  10. 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...

  11. Studies of some isomeric yield ratios produced with bremsstrahlung

    CERN Document Server

    Kolev, D

    1998-01-01

    The experimental isomeric ratios for sup 5 sup 2 sup m sup , sup g Mn, sup 8 sup 6 sup m sup , sup g Y, sup 8 sup 7 sup m sup , sup g Y, sup 8 sup 9 sup m sup , sup g Zr, sup 1 sup 1 sup 0 sup m sup , sup g In, sup 1 sup 1 sup 1 sup m sup , sup g In, sup 1 sup 1 sup 2 sup m sup , sup g In, sup 1 sup 5 sup 2 sup m sup 1 sup , sup g Pm, sup 1 sup 5 sup 2 sup m sup 2 sup , sup m sup 1 Eu, sup 1 sup 6 sup 2 sup m sup , sup g Ho, sup 1 sup 6 sup 4 sup m sup , sup g Ho and sup 1 sup 7 sup 8 sup m sup , sup g Lu measured by the activation technique from different targets in (gamma, xnp) reactions (x<=3) at the bremsstrahlung end-point energy of 43 MeV are presented. The predictions of calculations performed by means of compound nucleus particle evaporation and final gamma-deexcitation were critically discussed. The importance of inclusion in the calculations of nonequilibrium particle emission and an adequate gamma-decay mode of isomeric nuclei was considered for some of the reactions investigated.

  12. Bremsstrahlung radiation detection for small animal imaging using a CCD detector.

    Science.gov (United States)

    Spinelli, Antonello E; Boschi, Federico

    2016-05-01

    The use of optical methods for the detection of radionuclides is becoming an established tool for preclinical molecular imaging experiments. In this paper we present a set of proof of principle experiments showing that planar bremsstrahlung radiation images can be detected with an intensifying screen using a small animal optical imager based on charge coupled device detector. We develop a bremsstrahlung source using a (32)P-ATP vial placed in a Plexiglas box, the source with an intensifying screen on top was placed inside a small animal optical imaging system. Bremsstrahlung radiation images were produced with the (32)P-ATP source only and also with a pair of pliers placed between the source and the screen. We found that the pair of pliers absorption image matches the shape of the object. Spatial resolution measurements were not performed however, the bremsstrahlung image of the pliers show that the resolution is relatively poor due to a large penumbra effect. We conclude that it is possible to produce planar bremsstrahlung images using optical imaging devices. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Z-dependence of thick-target bremsstrahlung produced by monoenergetic low-energy electrons

    Energy Technology Data Exchange (ETDEWEB)

    Czarnecki, S.; Short, A.; Williams, S., E-mail: scott.williams@angelo.edu

    2016-07-01

    The dependence of thick-target bremsstrahlung emitted by low-energy beams of monoenergetic electrons on the atomic number of the target material has been investigated experimentally for incident electron energies of 4.25 keV and 5.00 keV using thick aluminum, copper, silver, tungsten, and gold targets. Experimental data suggest that the intensity of the thick-target bremsstrahlung emitted is more strongly dependent on the atomic number of the target material for photons with energies that are approximately equal to the energy of the incident electrons than at lower energies, and also that the dependence of thick-target bremsstrahlung on the atomic number of the target material is stronger for incident electrons of higher energies than for incident electrons of lower energies. The results of the experiments are compared to the results of simulations performed using the PENELOPE program (which is commonly used in medical physics) and to thin-target bremsstrahlung theory, as well. Comparisons suggest that the experimental dependence of thick-target bremsstrahlung on the atomic number of the target material may be slightly stronger than the results of the PENELOPE code suggest.

  14. LPM Interference and Cherenkov-like Gluon Bremsstrahlung in DenseMatter

    Energy Technology Data Exchange (ETDEWEB)

    Majumder, Abhijit; Wang, Xin-Nian

    2005-07-26

    Gluon bremsstrahlung induced by multiple parton scattering in a finite dense medium has a unique angular distribution with respect to the initial parton direction. A dead-cone structure with an opening angle; theta2{sub 0}; approx 2(1-z)/(zLE) for gluons with fractional energy z arises from the Landau-Pomeran chuck-Migdal (LPM) interference. In a medium where the gluon's dielectric constant is; epsilon>1, the LPM interference pattern is shown to become Cherenkov-like with an increased opening angle determined by the dielectric constant$/cos2/theta{sub c}=z+(1-z)//epsilon$. For a large dielectric constant/epsilon; gg 1+2/z2LE, the corresponding total radiative parton energy loss is about twice that from normal gluon bremsstrahlung. Implications of this Cherenkov-like gluon bremsstrahlung to the jet correlation pattern in high-energy heavy-ion collisions is discussed.

  15. 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.)

  16. Lectures from the workshop on nucleon-nucleon bremsstrahlung, January 25--26, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, B.F.; Schillaci, M.E.; Wender, S.A. (comps.)

    1990-07-01

    The Nucleon-Nucleon Bremsstrahlung Workshop was convened at LAMPF on 25--26 January 1990 in order to review the theoretical and experimental aspects of that reaction with focus on a possible new initiative to measure neutron-proton bremsstrahlung using the intermediate-energy, white-spectrum neutron source at the LAMPF/WNR facility. Over the course of this intense day-and-a-half workshop, experts in the field established the historical perspective for both theory and experiment, presented result of recent calculations, and examined new approaches to the difficult neutron-proton bremsstrahlung experiment. Theoretical and experimental working groups generated recommendations for action and actually converged upon a plan for an experimental program, not just a single measurement.

  17. Generation of bremsstrahlung during multiple passes of accelerated electrons through a thin target in a betatron

    Energy Technology Data Exchange (ETDEWEB)

    Bespalov, V.I. E-mail: bvi@chair12.phtd.tpu.edu.ru; Kashkovsky, V.V.; Chakhlov, V.L

    2003-01-01

    In the present work a method of bremsstrahlung generation in a betatron during multiple passes of the accelerated electrons through a thin target-converter is explored with the help of statistical modeling. The results are obtained on a basis of experimentally measured field distributions for the betatrons: MB-6 and B-35. The data of electron orbit dynamics and characteristics of bremsstrahlung field are given depending on parameters of the electron's dumping onto the target and sizes of the target.

  18. 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...

  19. Gas bremsstrahlung shielding calculation for first optic enclosure of ILSF XPD beamline.

    Science.gov (United States)

    Beigzadeh Jalali, H; Salimi, E; Rahighi, J

    2017-11-01

    Gas bremsstrahlung is generated in high energy electron storage ring and accompanies the synchrotron radiation into the beamlines, where both strike the various components of the beamline. In this paper, radiation shielding calculations for secondary gas bremsstrahlung are performed for the First Optics Enclosure (FOE) of X-ray powder diffraction (XPD) beamline of the Iranian Light Source Facility. Dose equivalent rate (DER) calculations are accomplished using FLUKA Monte Carlo code. A comprehensive study of DER distribution at the back wall, sides and roof are given. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. 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

  1. On electromagnetic off-shell effects in proton-proton bremsstrahlung

    OpenAIRE

    Kondratyuk, S.; Martinus, G.; Scholten, O.

    1997-01-01

    We study the influence of the off-shell structure of the nucleon electromagnetic vertex on proton-proton bremsstrahlung observables. Realistic choices for these off-shell effects are found to have considerable influences on observables such as cross sections and analyzing powers. The rescattering contribution diminishes the effects of off-shell modifications in negative-energy states.

  2. Proton-proton bremsstrahlung cross-sections including the kinematical singularity

    NARCIS (Netherlands)

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

    Integrated cross-section data for proton-proton bremsstrahlung including the points with the phase-space singularity, which occurs close to the maximum non-coplanarity angle, are presented. A numerical integration of theoretical cross-sections is performed over the non-coplanarity angle to integrate

  3. 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.

  4. 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....

  5. Non-relativistic Bremsstrahlung in QED: Hamiltonian vs. Path Integral Approach

    OpenAIRE

    Jahan, A.

    2012-01-01

    An alternative derivation of the radiation intensity in non-relativistic bremsstrahlung is provided utilizing the path integral formalism. By integrating out the gauge field, one obtains the effective action which it's imaginary part is interpreted as the rate of photon production during the collision.

  6. Near-infrared Bremsstrahlung radiation measurements in an advanced beam-driven FRC plasma

    Science.gov (United States)

    Nations, Marcel; Gupta, Deepak; Bolte, Nathan; Thompson, Matthew C.; TAE Team

    2017-10-01

    In magnetically confined fusion plasmas, the effective ionic charge (Zeff) is a measure of plasma impurity content. Knowledge of Zeff profiles is critical since impurities can account for substantial radiative power losses. One method to determine Zeff is to measure the Bremsstrahlung continuum over a small spectral range free from line radiation. In TAE's C-2 and C-2U machines, impurities in apparently line-free regions near 523 nm overwhelmed the expected Bremsstrahlung signals and resulted in overestimated values of Zeff. The near-infrared region is less affected by impurities and better suited for accurate Bremsstrahlung continuum measurements. For C-2W, an upgraded diagnostic system will be deployed to measure Bremsstrahlung signals near 1000 nm. The near-infrared system uses a suite of silicon avalanche photodetectors paired with a Dα system to remove contributions from neutrals and attain improved Zeff estimates. A design scheme for measurements in an FRC at multiple lines-of-sight is presented and discussed.

  7. Bremsstrahlung component of the diffuse galactic gamma-ray emission at MeV energies

    Energy Technology Data Exchange (ETDEWEB)

    Sacher, W.; Schoenfelder, V.

    1984-04-15

    Recently the galactic plane has been resolved at low and medium ..gamma..-ray energies in the directions toward the center and anticenter. Spectral measurements are now available at those energies, where the contribution of ..pi../sup 0/-decay from nuclear reactions of cosmic-ray protons (and heavier nuclei) with interstellar matter can be neglected. Under the assumption that most of the observed ..gamma..-ray flux below 30 MeV is produced by electron bremsstrahlung, restrictions on the energy spectrum of cosmic-ray electrons in interstellar space below 100 MeV are derived. The most accurate bremsstrahlung production cross sections of Koch and Motz and of Blumental and Gould are used in order to derive the bremsstrahlung production spectrum in interstellar space down to 10 keV-photon energies. If the low-energy ..gamma..-ray emission, as seen by most observers, is indeed produced by electron bremsstrahlung, then a high interstellar electron flux at MeV energy results, which-at higher energies-connects to the upper limit derived by Cummings, Stone, and Vogt. Such a high low-energy electron flux would be able to explain the ionization rate of 1 x 10/sup -15/ ion pairs (H-atom/sup -1/ s/sup -1/) in H I regions. Because of uncertainties in the low-energy ..gamma..-ray measurements, however, no definite conclusion is possible yet.

  8. Benefits from bremsstrahlung distribution evaluation to get unknown information from specimen in SEM and TEM

    Science.gov (United States)

    Eggert, F.; Camus, P. P.; Schleifer, M.; Reinauer, F.

    2018-01-01

    The energy-dispersive X-ray spectrometer (EDS or EDX) is a commonly used device to characterise the composition of investigated material in scanning and transmission electron microscopes (SEM and TEM). One major benefit compared to wavelength-dispersive X-ray spectrometers (WDS) is that EDS systems collect the entire spectrum simultaneously. Therefore, not only are all emitted characteristic X-ray lines in the spectrum, but also the complete bremsstrahlung distribution is included. It is possible to get information about the specimen even from this radiation, which is usually perceived more as a disturbing background. This is possible by using theoretical model knowledge about bremsstrahlung excitation and absorption in the specimen in comparison to the actual measured spectrum. The core aim of this investigation is to present a method for better bremsstrahlung fitting in unknown geometry cases by variation of the geometry parameters and to utilise this knowledge also for characteristic radiation evaluation. A method is described, which allows the parameterisation of the true X-ray absorption conditions during spectrum acquisition. An ‘effective tilt’ angle parameter is determined by evaluation of the bremsstrahlung shape of the measured SEM spectra. It is useful for bremsstrahlung background approximation, with exact calculations of the absorption edges below the characteristic peaks, required for P/B-ZAF model based quantification methods. It can even be used for ZAF based quantification models as a variable input parameter. The analytical results are then much more reliable for the different absorption effects from irregular specimen surfaces because the unknown absorption dependency is considered. Finally, the method is also applied for evaluation of TEM spectra. In this case, the real physical parameter optimisation is with sample thickness (mass thickness), which is influencing the emitted and measured spectrum due to different absorption with TEM

  9. An instrument for the investigation of actinides with spin resolved photoelectron spectroscopy and bremsstrahlung isochromat spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S.-W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tobin, J. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chung, B. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2011-01-01

    A new system for spin resolved photoelectron spectroscopy and bremsstrahlung isochromat spectroscopy has been built and commissioned at Lawrence Livermore National Laboratory for the investigation of the electronic structure of the actinides.Actinide materials are very toxic and radioactive and therefore cannot be brought to most general user facilities for spectroscopic studies. The technical details of the new system and preliminary data obtained therein will be presented and discussed.

  10. Radial scanning diagnostics of bremsstrahlung and line emission in T-10 plasma

    Energy Technology Data Exchange (ETDEWEB)

    Nemets, A. R., E-mail: Nemets-AR@nrcki.ru; Krupin, V. A.; Klyuchnikov, L. A., E-mail: lklyuchnikov@list.ru; Korobov, K. V.; Nurgaliev, M. R. [National Research Centre Kurchatov Institute, Institute of Tokamak Physics (Russian Federation)

    2016-12-15

    The paper describes the scanning spectroscopic diagnostics designed for measurement of line integrated plasma radiation in two visible spectral ranges. This diagnostic system is aimed at measuring the bremsstrahlung absolute values and profile with high spatial resolution. The bremsstrahlung absolute values are used to determine the value and radial distribution of effective plasma ion charge Z{sub eff}(r) in T-10 discharges. The importance of Z{sub eff} measurement is due to its strong influence on plasma heating, confinement, and stability. The spatial distribution of emission for one of the chosen spectral lines is measured simultaneously with bremsstrahlung. The spatial resolution of measurements is ~1 cm, and the temporal resolution is up to 10 ms. The spectral equipment and methods for its calibration are described. Examples of line integrated brightness distribution in a “continuum window” of 5236 ± 6 Å and brightness of the lines C{sup 5+} (5291 Å), He{sup 1+} (4686 Å), and D{sub β} (4861 Å) are given. Flattening of the bremsstrahlung brightness profile in the central region of the plasma column in some discharges with sawtooth oscillations in the T-10 is observed. The measured effective ion charge profiles in ohmic discharges with high plasma density and low discharge currents demonstrate accumulation of light impurities at the column axis; as a consequence, quenching of sawtooth oscillations in some discharges is observed. The developed diagnostics provides necessary data for investigation of heat, particle, and current transport in the plasma of the T-10. Successful application of the obtained data on Z{sub eff}(r) for investigation of geodesic acoustic modes of plasma oscillations in the T-10 should be specially noted.

  11. Virtual Corrections to Bremsstrahlung in High-Energy Collider Physics LHC and $e^+ e^-$ Colliders

    CERN Document Server

    Yost, S A; Yost, Scott A.

    2006-01-01

    We describe radiative corrections to bremsstrahlung and their application to high energy collider physics, focusing on the applications to luminosity measurement, fermion pair production and radiative return. We review the status of one loop radiative corrections in BHLUMI and the KKMC, including cross checks with newer results developed independently for radiative return. We outline a YFS-exponentiated approach to the Drell-Yan process for LHC physics, including a discussion of the relevant radiative corrections.

  12. Efficiency improvements of x-ray simulations in EGSnrc user-codes using bremsstrahlung cross-section enhancement (BCSE).

    Science.gov (United States)

    Ali, E S M; Rogers, D W O

    2007-06-01

    This paper presents the implementation of the bremsstrahlung cross-section enhancement (BCSE) variance-reduction technique into the EGSnrc/BEAMnrc system. BCSE makes the simulation of x-ray production from bremsstrahlung targets more efficient; it does so by artificially making the rare event of bremsstrahlung emission more abundant, which increases the number of statistically-independent photons that contribute to reducing the variance of the quantity of interest without increasing the CPU time appreciably. BCSE does not perturb the charged-particle transport in EGSnrc and it is made compatible with all other variance-reduction techniques already used in EGSnrc and BEAMnrc, including range rejection, uniform bremsstrahlung splitting, and directional bremsstrahlung splitting. When optimally combining BCSE with splitting to simulate typical situations of interest in medical physics research and in clinical practice, efficiencies can be up to five orders of magnitude larger than those obtained with analog simulations, and up to a full order of magnitude larger than those obtained with optimized splitting alone (which is the state-of-the-art of the EGSnrc/BEAMnrc system before this study was carried out). This study recommends that BCSE be combined with the existing splitting techniques for all EGSnrc/BEAMnrc simulations that involve bremsstrahlung targets, both in the kilovoltage and megavoltage range. Optimum crosssection enhancement factors for typical situations in diagnostic x-ray imaging and in radiotherapy are recommended, along with an easy algorithm for simulation optimization.

  13. Detection of pulsed, bremsstrahlung-induced, prompt neutron capture gamma-rays with HPGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.L.

    1996-08-01

    The Idaho National Engineering Laboratory (INEL) is developing a novel photoneutron-based nondestructive evaluation technique which uses a pulsed, high-energy (up to 8-MeV) electron accelerator and gamma-ray spectrometry. Highly penetrating pulses of bremsstrahlung photons are produced by each pulse of electrons. Interrogating neutrons are generated by the bremsstrahlung photons interacting within a photoneutron source material. The interactions of the neutrons within a target result in the emission of elemental characteristic gamma-rays. Spectrometry is performed by analyzing the photoneutron-induced prompt gamma-rays acquired between accelerator pulses with a unique, high-purity germanium (HPGe) gamma-ray detection system using a modified transistor reset preamplifier. The detection system, the experimental configuration, and the accelerator operation used to characterize the detection system performance are described. Using a 6.5 MeV electron accelerator and a beryllium metal photoneutron source, gamma-ray spectra were successfully acquired for Al, Cu, polyethylene, NaC1, and depleted uranium targets as soon as 30 {mu}s after each bremsstrahlung (or x-ray) flash.

  14. 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.

  15. Time evolution of endpoint energy of Bremsstrahlung spectra and ion production from an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, Ollie [Los Alamos National Laboratory; Ropponen, Tommi [JYFL; Jones, Peter [JYFL; Kalvas, Taneli [JYFL

    2008-01-01

    Electron cyclotron resonance ion sources (ECRIS) are used to produce high charge state heavy ion beams for the use of nuclear and materials science, for instance. The most powerful ECR ion sources today are superconducting. One of the problems with superconducting ECR ion sources is the use of high radio frequency (RF) power which results in bremsstrahlung radiation adding an extra heat load to the cryostat. In order to understand the electron heating process and timescales in the ECR plasma, time evolution measurement of ECR bremsstrahlung was carried out. In the measurements JYFL 14 GHz ECRIS was operated in a pulsed mode and bremsstrahlung data from several hundred RF pulses was recorded. Time evolution of ion production was also studied and compared to one of the electron heating theories. To analyze the measurement data at C++ program was developed. Endpoint energies of the bremsstrahlung spectra as a function of axial magnetic field strength, pressure and RF power are presented and ion production timescales obtained from the measurements are compared to bremsstrahlung emission timescales and one of the stochastic heating theories.

  16. 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.

  17. The influence of bremsstrahlung on electric discharge streamers in N2, O2 gas mixtures

    DEFF Research Database (Denmark)

    Köhn, Christoph; Chanrion, Olivier; Neubert, Torsten

    2017-01-01

    concentrations: no oxygen, 1 ppm O2 and 20% O2, as in air. At these oxygen levels, UV-relative to bremsstrahlung ionization is zero, small, and large. The simulations are conducted with a particle-in-cell code in a cylindrically symmetric configuration at ambient electric field magnitudes three times......Streamers are ionization filaments of electric gas discharges. Negative polarity streamers propagate primarily through electron impact ionization, whereas positive streamers in air develop through ionization of oxygen by UV photons emitted by excited nitrogen; however, experiments show...

  18. Model dependence of the bremsstrahlung effects from the superluminal neutrino at OPERA

    CERN Document Server

    Bezrukov, Fedor

    2012-01-01

    We revisit the bremsstrahlung process of a superluminal neutrino motivated by OPERA results. From a careful analysis of the plane wave solutions of the superluminal neutrino, we find that the squared matrix elements contain additional terms from Lorentz violation due to the modified spin sum for the neutrino. We point out that the coefficients of the decay rate and the energy loss rate significantly depend on the details of the model, although the results are parametrically similar to the ones obtained by Cohen and Glashow [1]. We illustrate this from the modified neutral current interaction of neutrino with Lorentz violation of the same order as in the modified dispersion relation.

  19. Emerging Hawking-Like Radiation from Gravitational Bremsstrahlung Beyond the Planck Scale

    CERN Document Server

    Ciafaloni, Marcello; Veneziano, Gabriele

    2015-01-01

    We argue that, as a consequence of the graviton's spin-2, its bremsstrahlung in trans-planckian-energy ($E\\gg M_P$) gravitational scattering at small deflection angle can be nicely expressed in terms of helicity-transformation phases and their transfer within the scattering process. The resulting spectrum exhibits deeply sub-planckian characteristic energies of order $M_P^2/E \\ll M_P$ (reminiscent of Hawking radiation), a suppressed fragmentation region, and a reduced rapidity plateau, in broad agreement with recent classical estimates.

  20. The Virtual Correction to Bremsstrahlung in High-Energy e+ e- Annihilation: Comparison of Exact Results

    CERN Document Server

    Yost, S.A.; Jadach, S.; Ward, B.F.L.

    2004-01-01

    We have compared the virtual corrections to single hard bremsstrahlung as calculated by S. Jadach, M. Melles, B.F.L. Ward and S.A. Yost to several other expressions. The most recent of these comparisons is to the leptonic tensor calculated by J.H. Kuhn and G. Rodrigo for radiative return. Agreement is found to within a part in 10^5 or better, as a fraction of the Born cross section, for most of the range of photon energies. The massless limits have been shown to agree analytically to NLL order.

  1. 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.

  2. The probability density function of energy loss for an electron by bremsstrahlung radiation in a thickness of a target

    Science.gov (United States)

    Kia, Mohammad Reza

    2017-10-01

    The probability density function (PDF) of energy loss for an electron by bremsstrahlung radiation in a thickness of a target is obtained by solving the collision term of the Boltzmann equation for the Bethe-Heitler differential cross section. It is demonstrated that the values of the energy loss for an electron by bremsstrahlung radiation will be important in order to calculate the total energy loss when the amount of screening from the atomic electrons becomes important. In this case, a stochastic equation based on the electron energy and the target properties is derived to calculate the energy loss of an electron by bremsstrahlung radiation in a thickness of a target. The results obtained from this analysis are in good agreement with the experimental data and the folding theory for the PDFs of total energy loss for an electron at a certain depth of a target reported in the literature.

  3. Neutron–proton bremsstrahlung as a possible probe of high-momentum component in nucleon momentum distribution

    Directory of Open Access Journals (Sweden)

    Hui Xue

    2016-04-01

    Full Text Available Neutron-proton bremsstrahlung in intermediate energy nucleus–nucleus collisions is proposed as a possible probe to study the high-momentum component in nucleon momentum distribution of finite nucleus. Based on the Boltzmann–Uehling–Uhlenbeck (BUU transport model, the effects of high-momentum component on the production of bremsstrahlung photons in the reaction of C12+12C collisions at different incident beam energies are studied. It is found that the high-momentum component increases the high-energy bremsstrahlung photon production remarkably. Furthermore, the ratio of photon production at different incident beam energies is suggested as a potential observable to probe the high-momentum component in nucleon momentum distribution of finite nucleus.

  4. 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.

  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. Formation region effects in transition radiation, bremsstrahlung, and ionization loss of ultrarelativistic electrons

    Directory of Open Access Journals (Sweden)

    S. V. Trofymenko

    2016-11-01

    Full Text Available The processes of transition radiation and bremsstrahlung by an ultrarelativistic electron as well as the effect of transition radiation influence upon the electron ionization loss in thin layer of substance are theoretically investigated in the case when radiation formation region has macroscopically large size. Special attention is drawn to transition radiation (TR generated during the traversal of thin metallic plate by the electron previously deflected from its initial direction of motion. In this case TR characteristics are calculated for realistic (circular shape of the electron deflection trajectory. The difference of such characteristics under certain conditions from the ones obtained previously with the use of approximation of anglelike shape of the electron trajectory (instant deflection is shown. The problem of measurement of bremsstrahlung characteristics in the prewave zone is investigated. The expressions defining the measured radiation distribution for arbitrary values of the size and the position of the detector used for radiation registration are derived. The problem of TR influence upon the electron ionization loss in thin plate and in a system of two plates is discussed. The proposal for experimental investigation of such effect is formulated.

  7. Effect of degenerate particles on internal bremsstrahlung of Majorana dark matter

    Directory of Open Access Journals (Sweden)

    Hiroshi Okada

    2015-11-01

    Full Text Available Gamma-rays induced by annihilation or decay of dark matter can be its smoking gun signature. In particular, gamma-rays generated by internal bremsstrahlung of Majorana and real scalar dark matter is promising since it can be a leading emission of sharp gamma-rays. However in the case of Majorana dark matter, its cross section for internal bremsstrahlung cannot be large enough to be observed by future gamma-ray experiments if the observed relic density is assumed to be thermally produced. In this paper, we introduce some degenerate particles with Majorana dark matter, and show they lead enhancement of the cross section. As a result, increase of about one order of magnitude for the cross section is possible without conflict with the observed relic density, and it would be tested by the future gamma-ray experiments such as GAMMA-400 and Cherenkov Telescope Array (CTA. In addition, the constraints of perturbativity, positron observation by the AMS experiment and direct search for dark matter are discussed.

  8. 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

  9. Calculation of gamma-ray buildup factors up to depths of 100 mfp by the method of invariant embedding. (2) Improved treatment of bremsstrahlung

    CERN Document Server

    Shimizu, A

    2003-01-01

    An improved method to calculate the gamma-ray buildup factors including bremsstrahlung has been developed. The exposure buildup factors with bremsstrahlung were computer by the present method for lead, iron and water at the source energy of 10.0 MeV up to depths of 100 mfp. The accuracy of the present method was checked by comparison with the calculations by use of EGS4. Excellent agreement was obtained between the calculations by both methods about the exposure buildup factors per energy (energy spectrum of transmitted photons) for lead up to depths of 10 mfp and the ratio of the exposure buildup factor with bremsstrahlung to that without bremsstrahlung for lead, iron and water up to depths of 40 mfp. It is confirmed that the present method has an accuracy sufficient to be used to the generation of an improved set of gamma-ray buildup factors including bremsstrahlung. (author)

  10. 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.

  11. Comparison of analytical and Monte Carlo calculations of multi-photon effects in bremsstrahlung emission by high-energy electrons

    Energy Technology Data Exchange (ETDEWEB)

    Mangiarotti, A. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Coimbra (Portugal); Departamento de Fisica, Faculdade de Ciencias e Tecnologia da Universidade de Coimbra, Coimbra (Portugal); Sona, P., E-mail: pietro.sona@fi.infn.it [Dipartimento di Fisica e Astronomia, Universita degli Studi di Firenze, Polo Scientifico, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze (Italy); Ballestrero, S. [Department of Physics University of Johannesburg, Johannesburg (South Africa); CERN PH/ADT, Geneve (Switzerland); Uggerhoj, U.I.; Andersen, K.K. [Department of Physics and Astronomy, University of Aarhus, Aarhus (Denmark)

    2012-10-15

    Approximate analytical calculations of multi-photon effects in the spectrum of total radiated energy by high-energy electrons crossing thin targets are compared to the results of Monte Carlo type simulations. The limits of validity of the analytical expressions found in the literature are established. The separate contributions to spectral distortion of electromagnetic processes other than bremsstrahlung are also studied in detail.

  12. Pion-proton bremsstrahlung calculation and the experimental'' magnetic moment of. Delta. sup ++ (1232)

    Energy Technology Data Exchange (ETDEWEB)

    Lin, D.; Liou, M.K. (Department of Physics and Institute for Nuclear Theory, Brooklyn College of the City University of New York, Brooklyn, New York (USA)); Ding, Z.M. (Department of Physics, Central State University, Edmond, Oklahoma (USA) Department of Physics, Normandale Community College, Bloomington, Minnesota (USA))

    1991-11-01

    A bremsstrahlung amplitude in the special two-energy-two-angle (TETAS) approximation, which is relativistic, gauge invariant, and consistent with the soft-photon theorem, is derived for the pion-proton bremsstrahlung ({pi}{sup +}{ital p}{gamma}) process near the {Delta}{sup ++}(1232) resonance. In order to take into account bremsstrahlung emission from an internal {Delta}{sup ++} line with both charge and the anomalous magnetic moment {lambda}{sub {Delta}}, we have applied a radiation decomposition identity to modify Low's standard prescription for constructing a soft-photon amplitude. This modified procedure is very general; it can be used to derive the TETAS amplitude for any bremsstrahlung process with resonance. The derived TETAS amplitude is applied to calculate all {pi}{sup +}{ital p}{gamma} cross sections which can be compared with the experimental data. Treating {lambda}{sub {Delta}} as a free parameter in these calculations, we extract the experimental'' magnetic moment of the {Delta}{sup ++}, {mu}{sub {Delta}}, from recent data. The extracted values of {mu}{sub {Delta}} are (3.7--4.2){ital e}/(2{ital m}{sub {ital p}}) from the University of California, Los Angeles data and (4.6--4.9){ital e}/(2{ital m}{sub {ital p}}) from the Paul Scherrer Institute data. Here, {ital m}{sub {ital p}} is the proton mass.

  13. 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.

  14. 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.

  15. Model dependence of the bremsstrahlung effects from the superluminal neutrino at OPERA

    Science.gov (United States)

    Bezrukov, Fedor; Lee, Hyun Min

    2012-02-01

    We revisit the bremsstrahlung process of a superluminal neutrino motivated by OPERA results. From a careful analysis of the plane-wave solutions of the superluminal neutrino, we find that the squared matrix elements contain additional terms from Lorentz violation due to the modified spin sum for the neutrino. We point out that the coefficients of the decay rate and the energy loss rate significantly depend on the details of the model, although the results are parametrically similar to the ones obtained by Cohen and Glashow [A. G. Cohen and S. L. Glashow, Phys. Rev. Lett. 107, 181803 (2011).PRLTAO0031-900710.1103/PhysRevLett.107.181803]. We illustrate this from the modified neutral current interaction of neutrino with Lorentz violation of the same order as in the modified dispersion relation.

  16. Improved electron reconstruction in ATLAS using the Gaussian Sum Filter-based model for bremsstrahlung

    CERN Document Server

    The ATLAS collaboration

    2012-01-01

    The behavior of high-energy electrons in the ATLAS Inner Detector is dominated by radiative energy losses (bremsstrahlung)as they traverse matter. These can be significant considering the substantial amount of material that the Inner Detector contains and can give rise to deviations from the original charged particle's path as it propagates through the magnetic field. As a result, significant inefficiencies, both during the electron trajectory reconstruction and in the determination of the corresponding track parameters in the bending plane, can be observed. In this note, we present a modification of the electron reconstruction in ATLAS that uses track refitting with the Gaussian Sum Filter (GSF) algorithm, with the aim of improving the estimated electron track parameters. The performance of this new scheme is compared to that of the existing standard electron reconstruction, for electron transverse energies between 7 GeV and 80 GeV.

  17. Bremsstrahlung x ray spectra of Jupiter and Saturn: Predictions for future planetary spacecraft

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, D.D. (Univ. of California, Los Angeles (USA))

    1990-07-01

    Calculations of X ray spectra due to bremsstrahlung from precipitating auroral electrons at Jupiter and Saturn are presented. The model assumes that a field-aligned potential drop accelerates a primary beam of electrons into the atmosphere where a population of secondary electrons having a power law energy dependence is generated. The spectrum at Jupiter is normalized to the soft X ray observations of Metzger et al (1983) at the low-energy end and constrained at the high-energy end by UV auroral energy requirements. The spectrum at Saturn is constructed by analogy to the Jovian case allowing for variation of the beam energy, energy flux, and scale size of the Saturnian aurora. The resulting indicate that a significant flux of X rays is emanating from both planets which may serve as a basis for conducting planetary X ray astronomy as part of future spacecraft missions to the planets.

  18. 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.

  19. Validation of the GEANT4 simulation of bremsstrahlung from thick targets below 3 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Pandola, L., E-mail: pandola@lns.infn.it [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, I-95125 Catania (Italy); INFN, Gran Sasso Science Institute, Viale Francesco Crispi 7, I-67100 L’Aquila (Italy); Andenna, C. [INAIL, Dipartimento Innovazioni Tecnologiche e Sicurezza degli Impianti, Prodotti ed Insediamenti Antropici, Via Alessandria 220, I-00198 Roma (Italy); Caccia, B. [Dipartimento Tecnologie e Salute, Istituto Superiore di Sanità and INFN, Gruppo Collegato dell’Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Roma (Italy)

    2015-05-01

    The bremsstrahlung spectra produced by electrons impinging on thick targets are simulated using the GEANT4 Monte Carlo toolkit. Simulations are validated against experimental data available in literature for a range of energy between 0.5 and 2.8 MeV for Al and Fe targets and for a value of energy of 70 keV for Al, Ag, W and Pb targets. The energy spectra for the different configurations of emission angles, energies and targets are considered. Simulations are performed by using the three alternative sets of electromagnetic models that are available in GEANT4 to describe bremsstrahlung. At higher energies (0.5–2.8 MeV) of the impinging electrons on Al and Fe targets, GEANT4 is able to reproduce the spectral shapes and the integral photon emission in the forward direction. The agreement is within 10–30%, depending on energy, emission angle and target material. The physics model based on the Penelope Monte Carlo code is in slightly better agreement with the measured data than the other two. However, all models over-estimate the photon emission in the backward hemisphere. For the lower energy study (70 keV), which includes higher-Z targets, all models systematically under-estimate the total photon yield, providing agreement between 10% and 50%. The results of this work are of potential interest for medical physics applications, where knowledge of the energy spectra and angular distributions of photons is needed for accurate dose calculations with Monte Carlo and other fluence-based methods.

  20. 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)

  1. 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

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

    Science.gov (United States)

    Habash Krause, L.; Gilchrist, B. E.; Nishikawa, K.; Williams, A.

    2013-12-01

    Relativistic 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 suborbital Reusable Launch Vehicle (sRLV) altitudes. The monoenergetic beam is modeled in cylindrical symmetry 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 bremmstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry that relies on sRLVs with a nominal apogee of 100 km. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.

  3. Comparison of Exact Results for the Virtual Corrections to Bremsstrahlung in Electron-Positron Annihilation at High Energies

    CERN Document Server

    Yost, S.A.; Jadach, S.; Ward, B.F.L.

    2004-01-01

    We have compared the virtual corrections to electron-positron annihilation to fermion pairs with single hard bremsstrahlung as calculated by S. Jadach, M. Melles, B.F.L. Ward and S.A. Yost to several other expressions. The most recent of these comparisons is to the leptonic tensor calculated by J.H. Kuhn and G. Rodrigo for radiative return. Agreement is found to within $10^{-5}$ or better, as a fraction of the Born cross section.

  4. Induced depletion of ^108mAg with 6 MeV bremsstrahlung

    Science.gov (United States)

    Carroll, J.; Litz, M.; Netherton, K.; Henriquez, S.; Pereira, N.; Karamian, S.

    2012-03-01

    The nuclide ^108Ag possesses an interesting combination of a long-lived isomer (T1/2 = 418 years, I^π = 6^+, E = 109 keV) and a short-lived ground state (T1/2 = 2.37 minutes, I^π = 1^+). The ground state decays primarily by β^- emission with Qβ- = 1,649 keV. A search of the available nuclear data (e. g., ENSDF and Phys. Rev. C 52, 104 (1995)) suggests two possible transitions at energies below 500 keV from the isomer to higher-lying levels, whose subsequent decay can branch to the ground state. This process would lead to a partial depletion of any population trapped within the isomeric state, ^108mAg. Currently, the cross section for induced isomer depletion via these transitions cannot be accurately deduced due to unknown branching ratios, and level widths and spins. Other ``depletion'' levels requiring excitation > 500 keV are also likely. An experimental test of ^108mAg depletion has been performed using 6 MeV bremsstrahlung at the US Army Research Laboratory, with isomeric targets and a computer-controlled repetitive measurement system. The design of the system and experimental results will be discussed.

  5. Enhancing Bremsstrahlung production from ultraintense laser-solid interactions with front surface structures

    Science.gov (United States)

    Jiang, Sheng; Krygier, Andrew G.; Schumacher, Douglass W.; Akli, Kramer U.; Freeman, Richard R.

    2014-10-01

    We report the results of a combined study of particle-in-cell and Monte Carlo modeling that investigates the production of Bremsstrahlung radiation produced when an ultraintense laser interacts with a tower-structured target. These targets are found to significantly narrow the electron angular distribution as well as produce significantly higher energies. These features combine to create a significant enhancement in directionality and energy of the Bremstrahlung radiation produced by a high-Z converter target. These studies employ short-pulse, high intensity laser pulses, and indicate that novel target design has potential to greatly enhance the yield and narrow the directionality of high energy electrons and γ-rays. We find that the peak γ-ray brightness for this source is 6.0 × 1019 s-1 mm-2 mrad-2 at 10 MeV and 1.4 × 1019 s-1 mm-2 mrad-2 at 100 MeV (0.1% bandwidth). Contribution to the Topical Issue "X-ray generation from ultrafast lasers", edited by Germán J. de Valcárcel, Luis Roso and Amelle Zaïr.

  6. Determination of EPID convolution kernels for portal imaging using carbon target bremsstrahlung

    Directory of Open Access Journals (Sweden)

    Lüdeke Sascha

    2017-09-01

    Full Text Available Improving the accuracy and reproducibility during patient positioning is of paramount importance. Hence, the goal of this work is to characterize the aspects of image blurring occurring during carbon target bremsstrahlung portal imaging and to assess the applicability of a deconvolution algorithm. Blurring effects involved in this method of portal imaging are electron scattering inside the EPID, geometric blurring due to the photon source size and photon scattering inside the patient. These effects can all be described by convolutions using as the convolutional kernel a Lorentz function, whose FWHM is 2λ. The λ values measured for these effects range from 0.2 mm to 0.45 mm, and an iterative 2D-deconvolution of carbon target portal images was performed accordingly. A significant decrease in the image blurring of test objects has been achieved and confirmed by analyzing the RMTF. However for clinical images, the deconvolution method is presently faced with the problem of the associated increase of image noise.

  7. A review of electron-nucleus bremsstrahlung cross sections between 1 and 10 MeV

    Science.gov (United States)

    Mangiarotti, A.; Martins, M. N.

    2017-12-01

    More than 80 years have passed since the first calculations of electron-nucleus bremsstrahlung cross sections were published by Sommerfeld, for non-relativistic electrons, and, independently, by Sauter, Bethe and Heitler, and Racah, for relativistic electrons. The Bethe-Heitler expression, that is based on the first Born approximation and includes the screening of the Coulomb field of the nucleus by the atomic electrons, has proven to work well at moderately high energies where the Landau-Pomeranchuk-Migdal effect is negligible. We review the current theoretical and experimental status with a highlight on electrons with kinetic energies between 1 and 10 MeV. The choice is motivated by the peculiar difficulties present in this energy region, where it is necessary to treat simultaneously the interaction with the Coulomb field beyond the first Born approximation and the effect of screening. A fully numerical approach within the S-matrix formalism has proven to be extremely difficult above a few MeV, because the number of partial waves needed for an accurate evaluation is prohibitively large. Here we focus on analytic results, including the more complex ones employing the Furry-Sommerfeld-Maue wave functions and taking into account the next-to-leading order, and discuss the advantages and limitations in light of the best available data. The influence of multiple scattering in the target is investigated under the actual experimental conditions. A comparison with the widely used cross section tabulations by Seltzer and Berger is also presented.

  8. 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)

  9. Effect of soft-core potentials on inverse bremsstrahlung heating during laser matter interactions

    Science.gov (United States)

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

    2017-07-01

    Inverse bremsstrahlung heating (IBH) is studied by using scattering theory for the interaction of intense lasers with matter using soft-core potentials. This involves three different kinds of interactions: (i) the interaction of the electrons with the external laser field, (ii) the electron-ion interaction, and (iii) the electron-electron interaction. In the interaction of rare-gas clusters with ultrashort laser pulses, nano-plasmas with high densities are created. A new scaling for the differential cross-section and the rate of energy absorption via IBH is derived which depends on the external laser field as well as electric field due to the other particles. When the particles are treated as charge distributions, the electric fields due to the other particles depend on a parameter of the non-Coulombic soft-core field, the potential depth, often used to avoid the Coulomb singularity. Thus, the rate of IBH also depends on the potential depth. Calculations are performed for electrons in a range of wavelength regimes from the vacuum ultraviolet to the mid-infrared. The rate of energy absorption via IBH is found to increase rapidly with increases in the potential depth and then quickly becomes mostly saturated at the Coulomb value for greater depths. The rate of energy absorption via IBH is found to be non-linear with laser intensities. The differential cross-section as well as the rate of energy absorption of IBH is found to increase with increases in laser wavelength. Finally, lower laser intensities saturate more slowly, requiring a larger potential depth to saturate.

  10. Approximation of the energy spectrum of a high-intense Bremsstrahlung source by the moments method using the attenuation curve

    CERN Document Server

    Nedavnij, O I

    2001-01-01

    A method of approximating energy spectrum of high-intensity Bremsstrahlung sources by the method of moments along attenuation curve is suggested. The method is based on preliminary differentiation of dependence of effective factor of radiation attenuation, calculation of random energy value moments and use of orthogonal polynomials. Analysis of results of mathematical experiment suggests that the method is fit for approximating energy spectra. Root-mean-square error of the approximation in the specific example made up 5% at most at initial error of 0.2%

  11. A search for bremsstrahlung solar axions using the Majorana low-background BEGe detector at Kimballton (MALBEK)

    OpenAIRE

    Abgrall, N.; Aguayo, E.; Avignone III, F.T.; Barabash, A.S.; Bertrand, F. E.; Boswell, M; Brudanin, V.; Busch, M; Caldwell, A.S.; Chan, Y-D.; Christofferson, C. D.(South Dakota School of Mines and Technology, Rapid City, SD 57701, USA); Combs, D. C.; Cooper, R. J.; Creswick, R J; Detwiler, J.A.

    2014-01-01

    A low-background, high-purity germanium detector has been used to search for evidence of low-energy, bremsstrahlung-generated solar axions. An upper bound of $1.36\\times 10^{-11}$ $(95% CL)$ is placed on the direct coupling of DFSZ model axions to electrons. The prospects for the sensitivity of the Majorana Demonstrator array of point-contact germanium detectors to solar axions are discussed in the context of the model-independent annual modulation due to the seasonal variation of the earth-s...

  12. 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.

  13. Maximization Of Bremsstrahlung And K-Series Production Efficiencies In Flash X-Ray Tubes

    Science.gov (United States)

    Krehl, Peter

    1986-08-01

    Historically, x-ray output of flash x-ray tubes was maximized empirically by changing the electrode geometry and varying the capacitance of the pulse generator. With the advent of high-voltage, low-impedance transmission lines, short-duration, high-current pulses could be generated with ease. An appropriate line scaling should assure that dose maximization is not reached at the expense of pulse prolongation which would reduce stop motion capability, but rather that dose rate should be maximized. Additionally, anode evaporation in the arc phase should be minimized to enhance tube life. Typically, the impedance of flash tubes changes during the discharge from infinity in the beginning to nearly zero in the arc phase and, either for field emission or high-vacuum discharge tubes, can well be modeled by a time-varying ohmic resistor Zx(t). Using a modification of Bergeron's method of travelling wave analysis, transient tube voltage and current can be determined out of a closed-form solution. This allows to calculate corresponding dose rate-time profiles of each spectrum. An ideal pulsed transmission line, charged up to a dc potential U0, has been assumed, characterized by its characteristic impedance Z0 and characteristic time T. Three typical examples illustrate the importance of optimum line scaling and K-series excitation voltage on tube performance such as dose, maximum dose rate, discharge delay time and pulse width. These examples encompass a transmission line with (a) constant initially stored energy E0 = UO2T/4Z0, but various combinations of Zo and T; (b) increasing energy E0 by decreasing Z0, but T = const; and (c) constant line parameters Z0 and T, but assumption of various Zx(t) profiles. Basic matching rules have been worked out in order to approach ideal operation for a given tube impedance time profile. A parametric analysis revealed that, with decreasing pulser impedance, there are increases in the bremsstrahlung and K-series radiation emissions, but that

  14. Dose calculations using MARS for Bremsstrahlung beam stops and collimators in APS beamline stations.

    Energy Technology Data Exchange (ETDEWEB)

    Dooling, J.; Accelerator Systems Division (APS)

    2010-11-01

    The Monte Carlo radiation transport code MARS is used to model the generation of gas bremsstrahlung (GB) radiation from 7-GeV electrons which scatter from residual gas atoms in undulator straight sections within the Advanced Photon Source (APS) storage ring. Additionally, MARS is employed to model the interactions of the GB radiation with components along the x-ray beamlines and then determine the expected radiation dose-rates that result. In this manner, MARS can be used to assess the adequacy of existing shielding or the specifications for new shielding when required. The GB radiation generated in the 'thin-target' of an ID straight section will consist only of photons in a 1/E-distribution up to the full energy of the stored electron beam. Using this analytical model, the predicted GB power for a typical APS 15.38-m insertion device (ID) straight section is 4.59 x 10{sup -7} W/nTorr/mA, assuming a background gas composed of air (Z{sub eff} = 7.31) at room temperature (293K). The total GB power provides a useful benchmark for comparisons between analytical and numerical approaches. We find good agreement between MARS and analytical estimates for total GB power. The extended straight section 'target' creates a radial profile of GB, which is highly peaked centered on the electron beam. The GB distribution reflects the size of the electron beam that creates the radiation. Optimizing the performance of MARS in terms of CPU time per incident trajectory requires the use of a relatively short, high-density gas target (air); in this report, the target density is {rho}L = 2.89 x 10{sup -2} g/cm{sup 2} over a length of 24 cm. MARS results are compared with the contact dose levels reported in TB-20, which used EGS4 for radiation transport simulations. Maximum dose-rates in 1 cc of tissue phantom form the initial basis for comparison. MARS and EGS4 results are approximately the same for maximum 1-cc dose-rates and attenuation in the photon

  15. Bremsstrahlung and K(alpha) fluorescence measurements for inferring conversion efficiencies into fast ignition relevant hot electrons

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C D; Patel, P K; Hey, D S; Mackinnon, A J; Key, M H; Akli, K U; Bartal, T; Beg, F N; Chawla, S; Chen, H; Freeman, R R; Higginson, D P; Link, A; Ma, T Y; MacPhee, A G; Stephens, R B; Van Woerkom, L D; Westover, B; Porkolab, M

    2009-07-24

    The Bremsstrahlung and K-shell emission from 1 mm x 1 mm x 1 mm planar targets irradiated by a short-pulse 3 x 10{sup 18}-8 x 10{sup 19} W/cm{sup 2} laser were measured. The Bremsstrahlung was measured using a filter stack spectrometer with spectral discrimination up to 500 keV. K-shell emission was measured using a single photon counting charge coupled device (CCD). From Monte Carlo modeling of the target emission, conversion efficiencies into 1-3 MeV electrons of 3-12%, representing 20-40% total conversion efficiencies were inferred for intensities up to 8 x 10{sup 19} W/cm{sup 2}. Comparisons to scaling laws using synthetic energy spectra generated from the intensity distribution of the focal spot imply slope temperatures less than the ponderomotive potential of the laser. Resistive transport effects may result in potentials of a few hundred kV in the first few tens of microns in the target. This would lead to higher total conversion efficiencies than inferred from Monte Carlo modeling but lower conversion efficiencies into 1-3 MeV electrons.

  16. Shielding calculation constants for use in effective dose evaluation for photons, neutrons and Bremsstrahlung from beta-ray

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Yukio; Endo, Akira; Tsuda, Shuichi; Takahashi, Fumiaki; Yamaguchi, Yasuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-01-01

    Dose quantity in the shielding design calculation will be changed from the 1 cm depth dose equivalent to effective dose on the occasion of the introduction of International Commission on Radiological Protection (ICRP) 1990 Recommendations (ICRP Publication 60) into domestic laws. In the shielding calculation for the radiation facilities, simple dose estimation methods by using the shielding calculation constants instead of calculation of radiation energy spectra behind the shielding materials are effective and widely used. These shielding calculation constants depend on the dose quantity to be estimated and those for the evaluation of 1 cm depth dose equivalents should be replaced by those for the evaluation of effective dose. In the present report, the shielding calculation constants are summarized for photons, neutrons and Bremsstrahlung from beta-ray. For mono-energetic photons with energies from 0.015 MeV to 10 MeV, effective dose buildup factors, effective conversion coefficients from air kerma to effective dose and transmission data of effective dose were calculated. Effective dose rate constants, which represent an effective dose value at 1 m apart from a source without shielding, and transmission data of effective dose were also calculated for gamma-ray and X-ray from 33 radioisotopes, Bremsstrahlung from 13 radioisotopes beta-ray and 4 neutron sources. (author)

  17. An assessment of the Photon Contamination due to Bremsstrahlung Radiation in the Electron Beams of a NEPTUN 10PC Linac using a Monte Carlo Method

    Directory of Open Access Journals (Sweden)

    Nasrollah Jabbari

    2009-03-01

    Full Text Available Introduction: In clinical electron beams, most of bremsstrahlung radiation is produced by various linac head structures. This bremsstrahlung radiation dose is influenced by the geometry and construction of every component of the linac treatment head structures. Thus, it can be expected that the amount of the contaminated photon dose due to bremsstrahlung radiation varies among different linacs, even for the same electron beam energy. The aims of this study were to simulate the NEPTUN 10PC linac electron beams and to calculate the photon contamination dose due to bremsstrahlung radiation in these beams using a Monte Carlo method. Materials and methods: A NEPTUN 10PC linac was simulated in its electron mode using the BEAMnrc code. This linac can provide three electron beam energies of 6, 8 and 10 MeV. Detailed information required for the simulation, including the geometry and materials of various components of the linac treatment head, was provided by the vender. For all simulations, the cut-off energies for electron and photon transport were set at ECUT=0.521 MeV and PCUT=0.010 MeV, respectively. The KS statistical test was used for validation of the simulated models. Then, relevant bremsstrahlung radiation doses for the three electron beam energies of the linac were calculated for the reference field using the Monte Carlo method.   Results: The KS test showed a good agreement between the calculated values (resulting from the simulations and the measured ones. The results showed that the amount of contaminated photon dose due to bremsstrahlung radiation from various components of the simulated linac at the surface of the phantom was between 0.2%-0.5% of the maximum dose for the three electron beam energies. Conclusion:  Considering the good agreement between the measured and simulated data, it can be concluded that the simulation method as well as the calculated bremsstrahlung doses have been made at a good level of accuracy and precision

  18. Study of the K shell photoelectric parameters of Dy, Yb and W atoms using low energy Bremsstrahlung radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hosur, S.B.; Naika, L.R.; Badiger, N.M. [Department of Studies in PhysicsKarnatak University, Dharwad - 580003 (India)

    2011-04-15

    Low energy external Bremsstrahlung (EB) photons were used to estimate the K shell photoelectric parameters; the K shell photoelectric cross section at the K edge, the K shell binding energy, the K shell jump ratio, the K shell jump factors, the Davisson-Kirchner ratio and the K shell oscillator strength for dysprosium (Dy), ytterbium (Yb) and tungsten (W) atoms. The EB photons are produced in the nickel (Ni) target by using the beta particles from a weak beta source of {sup 90}Sr-{sup 90}Y. These photons are made to fall on these elemental targets of our interest and the transmitted spectrum is measured using GMX 10P HPGe detector coupled to an 8K multichannel analyzer. The sharp decrease at the K edge in the measured spectrum is used to determine the K shell photoelectric parameters of these elements. The experimental results are in good agreement with the theoretical values. (authors)

  19. Study of the K shell photoelectric parameters of Dy, Yb and W atoms using low energy bremsstrahlung radiation

    Science.gov (United States)

    Hosur, S. B.; Naik, L. R.; Badiger, N. M.

    2011-04-01

    Low energy external bremsstrahlung (EB) photons were used to estimate the K shell photoelectric parameters; the K shell photoelectric cross section at the K edge, the K shell binding energy, the K shell jump ratio, the K shell jump factors, the Davisson-Kirchner ratio and the K shell oscillator strength for dysprosium (Dy), ytterbium (Yb) and tungsten (W) atoms. The EB photons are produced in the nickel (Ni) target by using the beta particles from a weak beta source of 90Sr-90Y. These photons are made to fall on these elemental targets of our interest and the transmitted spectrum is measured using GMX 10P HPGe detector coupled to an 8K multichannel analyzer. The sharp decrease at the K edge in the measured spectrum is used to determine the K shell photoelectric parameters of these elements. The experimental results are in good agreement with the theoretical values.

  20. Channeling and coherent bremsstrahlung effects for relativistic positrons and electrons. [16 to 28 MeV, orientation

    Energy Technology Data Exchange (ETDEWEB)

    Walker, R. L.

    1976-03-22

    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 ..mu..m 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.

  1. Design of field flattening filters for a high-power bremsstrahlung converter by full Monte Carlo simulation

    Science.gov (United States)

    Van Laere, K.; Mondelaers, W.

    1997-03-01

    To compensate for off-axis dose reduction, biconical-shaped Pb field flattening filters were constructed for a specific high-power static TaC bremsstrahlung target configuration, at end-point energies 5 and 10 MeV. The filter design was optimized by full Monte Carlo simulation. The absolute dose calculation was compared to experimental ionization and Fricke measurements. Spectral data were analysed and the influence of incident electron beam parameters (diameter, oblique incidence) was simulated. With the constructed filtered set-up we are able to produce any required γ-dose rate up to a maximum value of 35 kGy/h in a water phantom at SSD 25 cm. The accomplished homogeneity at this distance is better than a few per cent over a surface of 25 cm diameter perpendicular to the beam axis, for both energies.

  2. Comparison of TOF-PET and Bremsstrahlung SPECT Images of Yttrium-90: A Monte Carlo Simulation Study.

    Science.gov (United States)

    Takahashi, Akihiko; Himuro, Kazuhiko; Baba, Shingo; Yamashita, Yasuo; Sasaki, Masayuki

    2018-01-01

    Yttrium-90 ( 90 Y) is a beta particle nuclide used in targeted radionuclide therapy which is available to both single-photon emission computed tomography (SPECT) and time-of-flight (TOF) positron emission tomography (PET) imaging. The purpose of this study was to assess the image quality of PET and Bremsstrahlung SPECT by simulating PET and SPECT images of 90 Y using Monte Carlo simulation codes under the same conditions and to compare them. In-house Monte Carlo codes, MCEP-PET and MCEP-SPECT, were employed to simulate images. The phantom was a torso-shaped phantom containing six hot spheres of various sizes. The background concentrations of 90 Y were set to 50, 100, 150, and 200 kBq/mL, and the concentrations of the hot spheres were 10, 20, and 40 times of those of the background concentrations. The acquisition time was set to 30 min, and the simulated sinogram data were reconstructed using the ordered subset expectation maximization method. The contrast recovery coefficient (CRC) and contrast-to-noise ratio (CNR) were employed to evaluate the image qualities. The CRC values of SPECT images were less than 40%, while those of PET images were more than 40% when the hot sphere was larger than 20 mm in diameter. The CNR values of PET images of hot spheres of diameter smaller than 20 mm were larger than those of SPECT images. The CNR values mostly exceeded 4, which is a criterion to evaluate the discernibility of hot areas. In the case of SPECT, hot spheres of diameter smaller than 20 mm were not discernable. On the contrary, the CNR values of PET images decreased to the level of SPECT, in the case of low concentration. In almost all the cases examined in this investigation, the quantitative indexes of TOF-PET 90 Y images were better than those of Bremsstrahlung SPECT images. However, the superiority of PET image became critical in the case of low activity concentrations.

  3. 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)

  4. Optimization of energy window for 90Y bremsstrahlung SPECT imaging for detection tasks using the ideal observer with model-mismatch.

    Science.gov (United States)

    Rong, Xing; Ghaly, Michael; Frey, Eric C

    2013-06-01

    In yttrium-90 ((90)Y) microsphere brachytherapy (radioembolization) of unresectable liver cancer, posttherapy (90)Y bremsstrahlung single photon emission computed tomography (SPECT) has been used to document the distribution of microspheres in the patient and to help predict potential side effects. The energy window used during projection acquisition can have a significant effect on image quality. Thus, using an optimal energy window is desirable. However, there has been great variability in the choice of energy window due to the continuous and broad energy distribution of (90)Y bremsstrahlung photons. The area under the receiver operating characteristic curve (AUC) for the ideal observer (IO) is a widely used figure of merit (FOM) for optimizing the imaging system for detection tasks. The IO implicitly assumes a perfect model of the image formation process. However, for (90)Y bremsstrahlung SPECT there can be substantial model-mismatch (i.e., difference between the actual image formation process and the model of it assumed in reconstruction), and the amount of the model-mismatch depends on the energy window. It is thus important to account for the degradation of the observer performance due to model-mismatch in the optimization of the energy window. The purpose of this paper is to optimize the energy window for (90)Y bremsstrahlung SPECT for a detection task while taking into account the effects of the model-mismatch. An observer, termed the ideal observer with model-mismatch (IO-MM), has been proposed previously to account for the effects of the model-mismatch on IO performance. In this work, the AUC for the IO-MM was used as the FOM for the optimization. To provide a clinically realistic object model and imaging simulation, the authors used a background-known-statistically and signal-known-statistically task. The background was modeled as multiple compartments in the liver with activity parameters independently following a Gaussian distribution; the signal was

  5. Photoactivation of the p-nucleus {sup 92}Mo at the bremsstrahlung measurement place of ELBE; Photoaktivierung des p-Kerns {sup 92}Mo am Bremsstrahlungsmessplatz von ELBE

    Energy Technology Data Exchange (ETDEWEB)

    Erhard, Martin Andreas

    2010-02-26

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

  6. Comparisons of Fully Differential Exact Results for O(alpha) Virtual Corrections to Single Hard Bremsstrahlung in e+e- Annihilation at High Energies

    CERN Document Server

    Glosser, C; Ward, B F L; Yost, S A

    2004-01-01

    We present comparisons of the fully differential exact virtual correction to the important single hard bremsstrahlung process in e+e- annihilation at high energies, which is essential for precision studies of the Standard Model from 1 GeV to 1 TeV, as calculated by two completely independent methods and groups. We show that the two sets of results are in excellent agreement. Phenomenological implications are discussed.

  7. A general semi-analytic method to simulate discrete bremsstrahlung at very low radiated photon energies by the Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Mangiarotti, A. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Coimbra (Portugal); Departamento de Fisica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, Coimbra (Portugal); Sona, P., E-mail: pietro.sona@fi.infn.it [Dipartimento di Fisica, Universita degli Studi di Firenze, Polo Scientifico, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze, Polo Scientifico, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Ballestrero, S. [Department of Physics, University of Johannesburg, Johannesburg (South Africa); PH/ADT, CERN, CH-1211, Geneve (Switzerland); Uggerhoj, U.I. [Department of Physics and Astronomy, University of Aarhus, Aarhus (Denmark)

    2011-09-15

    A computer code for Monte-Carlo simulations in the framework of the GEANT 3 toolkit has been implemented for the description of the discrete bremsstrahlung radiation from high energy electrons crossing thick (semi-infinite) targets. The code is based on the Migdal theory which includes the LPM and dielectric suppression. Validation of the code has been performed by a comparison with the data from the SLAC E-146 experiment. The agreement between simulations and experimental data is generally very good.

  8. 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.

  9. The scattering of a bremsstrahlung radiation of electrons with energy 13 and 22 MeV from plane targets

    CERN Document Server

    Asatov, U T

    2002-01-01

    In the present work the characteristics of backward (90 sup d egbremsstrahlung radiation of electrons with energy 13 and 22 MeV with plane targets of different thickness from glass textolite, aluminium, iron, lead and their combination are investigated. The dependence of thickness of saturation of 'forward' scattered gamma radiation, a on angles of detection (theta sub s) and orientation (phi) of plane targets depending on a direction of probing beam was observed for the first time. For the first time, the numerical performances of beams of forward scattered gamma radiation from different targets were investigated and determined depending on their orientation and thickness. The new and corrected data on numerical performances of beams of the inverse scattered gamma radiation is obtained. The distinction in characteristics of beams of the scattered gamma radiation is s...

  10. A bremsstrahlung gamma-ray source based on stable ionization injection of electrons into a laser wakefield accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Döpp, A., E-mail: andreas.doepp@polytechnique.edu [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Centro de Laseres Pulsados, Parque Cientfico, 37185 Villamayor, Salamanca (Spain); Guillaume, E.; Thaury, C.; Lifschitz, A. [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Sylla, F. [SourceLAB SAS, 86 rue de Paris, 91400 Orsay (France); Goddet, J-P.; Tafzi, A.; Iaquanello, G.; Lefrou, T.; Rousseau, P. [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France); Conejero, E.; Ruiz, C. [Departamento de Física Aplicada, Universidad de Salamanca, Plaza de laMerced s/n, 37008 Salamanca (Spain); Ta Phuoc, K.; Malka, V. [LOA, ENSTA ParisTech, CNRS, École polytechnique, Université Paris-Saclay, 828 bd des Maréchaux, 91762 Palaiseau Cedex (France)

    2016-09-11

    Laser wakefield acceleration permits the generation of ultra-short, high-brightness relativistic electron beams on a millimeter scale. While those features are of interest for many applications, the source remains constraint by the poor stability of the electron injection process. Here we present results on injection and acceleration of electrons in pure nitrogen and argon. We observe stable, continuous ionization-induced injection of electrons into the wakefield for laser powers exceeding a threshold of 7 TW. The beam charge scales approximately with the laser energy and is limited by beam loading. For 40 TW laser pulses we measure a maximum charge of almost 1 nC per shot, originating mostly from electrons of less than 10 MeV energy. The relatively low energy, the high charge and its stability make this source well-suited for applications such as non-destructive testing. Hence, we demonstrate the production of energetic radiation via bremsstrahlung conversion at 1 Hz repetition rate. In accordance with GEANT4 Monte-Carlo simulations, we measure a γ-ray source size of less than 100 μm for a 0.5 mm tantalum converter placed at 2 mm from the accelerator exit. Furthermore we present radiographs of image quality indicators.

  11. Development of a low-energy x-ray camera for the imaging of secondary electron bremsstrahlung x-ray emitted during proton irradiation for range estimation

    Science.gov (United States)

    Ando, Koki; Yamaguchi, Mitsutaka; Yamamoto, Seiichi; Toshito, Toshiyuki; Kawachi, Naoki

    2017-06-01

    Imaging of secondary electron bremsstrahlung x-ray emitted during proton irradiation is a possible method for measurement of the proton beam distribution in phantom. However, it is not clear that the method is used for range estimation of protons. For this purpose, we developed a low-energy x-ray camera and conducted imaging of the bremsstrahlung x-ray produced during irradiation of proton beams. We used a 20 mm  ×  20 mm  ×  1 mm finely grooved GAGG scintillator that was optically coupled to a one-inch square high quantum efficiency (HQE)-type position-sensitive photomultiplier tube to form an imaging detector. The imaging detector was encased in a 2 cm-thick tungsten container, and a pinhole collimator was attached to its camera head. After performance of the camera was evaluated, secondary electron bremsstrahlung x-ray imaging was conducted during irradiation of the proton beams for three different proton energies, and the results were compared with Monte Carlo simulation as well as calculated value. The system spatial resolution and sensitivity of the developed x-ray camera with 1.5 mm-diameter pinhole collimator were estimated to be 32 mm FWHM and 5.2  ×  10-7 for ~35 keV x-ray photons at 100 cm from the collimator surface, respectively. We could image the proton beam tracks by measuring the secondary electron bremsstrahlung x-ray during irradiation of the proton beams, and the ranges for different proton energies could be estimated from the images. The measured ranges from the images were well matched with the Monte Carlo simulation, and slightly smaller than the calculated values. We confirmed that the imaging of the secondary electron bremsstrahlung x-ray emitted during proton irradiation with the developed x-ray camera has the potential to be a new tool for proton range estimations.

  12. The significance of Bremsstrahlung SPECT/CT after yttrium-90 radioembolization treatment in the prediction of extrahepatic side effects

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadzadehfar, Hojjat; Muckle, Marianne; Sabet, Amir; Biermann, Kim; Haslerud, Torjan; Biersack, Hans-Juergen; Ezziddin, Samer [University Hospital Bonn, Department of Nuclear Medicine, Bonn (Germany); Wilhelm, Kai [University Hospital Bonn, Department of Radiology, Bonn (Germany); Kuhl, Christiane [University Hospital Aachen, Department of Radiology, Aachen (Germany)

    2012-02-15

    Unwanted deposition of {sup 90}Y microspheres in organs other than the liver during radioembolization of liver tumours may cause severe side effects such as duodenal ulcer. The aim of this study was to evaluate the significance of posttherapy bremsstrahlung (BS) SPECT/CT images of the liver in comparison to planar and SPECT images in the prediction of radioembolization-induced extrahepatic side effects. A total of 188 radioembolization procedures were performed in 123 patients (50 women, 73 men) over a 2-year period. Planar, whole-body and BS SPECT/CT imaging were performed 24 h after treatment as a part of therapy work-up. Any focally increased extrahepatic accumulation was evaluated as suspicious. Clinical follow-up and gastroduodenoscopy served as reference standards. The studies were reviewed to evaluate whether BS SPECT/CT imaging was of benefit. In the light of anatomic data obtained from SPECT/CT, apparent extrahepatic BS in 43% of planar and in 52% of SPECT images proved to be in the liver and hence false-positive. The results of planar scintigraphy could not be analysed further since 12 images were not assessable due to high scatter artefacts. On the basis of the gastrointestinal (GI) complications and the results of gastroduodenoscopy, true-positive, true-negative, false-positive and false-negative results of BS SPECT and SPECT/CT imaging in the prediction of GI ulcers were determined. The sensitivity, specificity, positive and negative predictive values and the accuracy of SPECT and SPECT/CT in the prediction of GI ulcers were 13%, 88%, 8%, 92% and 82%, and 87%, 100%, 100%, 99% and 99%, respectively. Despite the low quality of BS images, BS SPECT/CT can be used as a reliable method to confirm the safe distribution of {sup 90}Y microspheres and in the prediction of GI side effects. (orig.)

  13. Electroweak and Higgs boson internal bremsstrahlung. General considerations for Majorana dark matter annihilation and application to MSSM neutralinos

    Science.gov (United States)

    Bringmann, Torsten; Calore, Francesca; Galea, Ahmad; Garny, Mathias

    2017-09-01

    It is well known that the annihilation of Majorana dark matter into fermions is helicity suppressed. Here, we point out that the underlying mechanism is a subtle combination of two distinct effects, and we present a comprehensive analysis of how the suppression can be partially or fully lifted by the internal bremsstrahlung of an additional boson in the final state. As a concrete illustration, we compute analytically the full amplitudes and annihilation rates of supersymmetric neutralinos to final states that contain any combination of two standard model fermions, plus one electroweak gauge boson or one of the five physical Higgs bosons that appear in the minimal supersymmetric standard model. We classify the various ways in which these three-body rates can be large compared to the two-body rates, identifying cases that have not been pointed out before. In our analysis, we put special emphasis on how to avoid the double counting of identical kinematic situations that appear for two-body and three-body final states, in particular on how to correctly treat differential rates and the spectrum of the resulting stable particles that is relevant for indirect dark matter searches. We find that both the total annihilation rates and the yields can be significantly enhanced when taking into account the corrections computed here, in particular for models with somewhat small annihilation rates at tree-level which otherwise would not be testable with indirect dark matter searches. Even more importantly, however, we find that the resulting annihilation spectra of positrons, neutrinos, gamma-rays and antiprotons differ in general substantially from the model-independent spectra that are commonly adopted, for these final states, when constraining particle dark matter with indirect detection experiments.

  14. Multifragmentation of heavy nuclei induced by coherent Bremsstrahlung protons with E subgamma sup m sup a sup x = 4.1 GeV

    CERN Document Server

    Bayatyan, G L; Grigoryan, N K; Knyazyan, S G; Margaryan, A; Marikian, G G; Rostomyan, T A; Likhachev, V P

    2002-01-01

    New experimental results on the multifragmentation of nuclei sup 1 sup 9 sup 7 Au, sup 2 sup 0 sup 9 Bi, sup 2 sup 3 sup 8 U, and sup 2 sup 4 sup 3 Am induced by the coherent Bremsstrahlung photon beam of the Yerevan Synchrotron, which has an end-point energy of 4.1 GeV, are reported. The measured yields of four or more fragments, observed for the first time for these nuclei are in the range approx (1-3) x 10 sup - sup 3 of the total inelastic cross section. The yields of fragments are isotropic

  15. Feasibility of bremsstrahlung dosimetry for direct dose estimation in patients undergoing treatment with {sup 90}Y-ibritumomab tiuxetan

    Energy Technology Data Exchange (ETDEWEB)

    Arrichiello, C.; Aloj, L.; Mormile, M.; D' Ambrosio, L.; Caraco, C.; De Martinis, F. [Istituto Nazionale per lo Studio e la Cura dei Tumori, Fondazione ' ' G. Pascale' ' , Nuclear Medicine Department, Napoli (Italy); Frigeri, F.; Arcamone, M.; Pinto, A. [Istituto Nazionale per lo Studio e la Cura dei Tumori, Fondazione ' ' G. Pascale' ' , Hematology-Oncology, Napoli (Italy); Stem Cells Transplantation Unit, Department of Hematology, Napoli (Italy); Lastoria, S. [Istituto Nazionale per lo Studio e la Cura dei Tumori, Fondazione ' ' G. Pascale' ' , Nuclear Medicine Department, Napoli (Italy); Istituto Nazionale per lo Studio e la Cura dei Tumori, Fondazione ' ' G. Pascale' ' , IRCCS, Napoli (Italy)

    2012-06-15

    on patient-specific dosimetry, the administered activity may be increased by an average factor of 2.4, indicating that most patients could be undertreated. The relative dosimetry approach based on planar imaging largely underestimates doses relative to reference values. Dosimetry based on planar bremsstrahlung imaging is not a dependable alternative to {sup 111}In dosimetry. (orig.)

  16. Optimization of the image contrast in SPECT-CT bremsstrahlung imaging for Selective Internal Radiation Therapy of liver malignancies with Y-90 microspheres

    CERN Document Server

    Bonutti, Faustino; Magro, Giuseppe; Cecotti, Andrea; Della Schiava, Emanuele; Del Dò, Elena; Longo, Francesco; Herassi, Yassine; Bentayeb, Farida; Rossi, Marina; Ferretti, Guido; Geatti, Onelio; Padovani, Renato

    2015-01-01

    The quality of SPECT Bremsstrahlung images of patients treated with Y-90 is poor, mainly because of scattered radiation and collimator septa penetration. To minimize the latter effect, High Energy (HE) or Medium Energy (ME) collimators can be used. Scatter correction is not possible through the methods commonly used for the diagnostic radionuclides (Tc-99m, etc.) because the Bremsstrahlung radiation does not have distinct photopeaks, but a broad spectrum of energies ranging from zero to the maximum one detectable by the gamma-camera crystal is registered. Scatter radiation and collimator septa penetration affect the Contrast and the Contrast Recovery Coefficient (CRC) : our research focused on finding the best energy position for the acquisition window in order to maximize these parameters. To be guided in this finding, we first made a Monte Carlo (MC) simulation of a SPECT acquisition of a Y-90 cylindrical phantom and then we measured at different energies the Line Spread Function (LSF) of a linear Y-90 sour...

  17. Use of bremsstrahlung radiation to identify hidden weak β‑ sources: feasibility and possible use in radio-guided surgery

    Science.gov (United States)

    Carlotti, D.; Collamati, F.; Faccini, R.; Fresch, P.; Iacoangeli, F.; Mancini-Terracciano, C.; Marafini, M.; Mirabelli, R.; Recchia, L.; Russomando, A.; Solfaroli Camillocci, E.; Toppi, M.; Traini, G.; Bocci, V.

    2017-11-01

    The recent interest in β^‑ radionuclides for radio-guided surgery derives from the feature of the β radiation to release energy in few millimeters of tissue. Such feature can be used to locate residual tumors with a probe located in its immediate vicinity, determining the resection margins with an accuracy of millimeters. The drawback of this technique is that it does not allow to identify tumors hidden in more than few mm of tissue. Conversely, the bremsstrahlung X-rays emitted by the interaction of the β‑ radiation with the nuclei of the tissue are relatively penetrating. To complement the β‑ probes, we have therefore developed a detector based on cadmium telluride, an X-ray detector with a high quantum efficiency working at room temperature. We measured the secondary emission of bremsstrahlung photons in a target of Polymethylmethacrylate (PMMA) with a density similar to living tissue. The results show that this device allows to detect a 1 ml residual or lymph-node with an activity of 1 kBq hidden under a layer of 10 mm of PMMA with a 3:1 signal to noise, i.e. with a five sigma discrimination in less than 5 s.

  18. Comparisons of Exact Results for the Virtual Photon Contribution to Single Harg Bremsstrahlung in Radiative Return for $e^{+}e^{-}$ Annihilation

    CERN Document Server

    Jadach, Stanislaw; Yost, S A

    2006-01-01

    We compare fully differential exact results for the virtual photon correction to single hard photon bremsstrahlung obtained using independent calculations, both for electron-positron annihilation at high-energy colliders and for radiative returnapplications. The results are compared using Monte Carlo evaluations of the matrix elements as well as by direct analytical evaluation of certain critical limits. Special attention is given to the issues of numerical stability and the treatment of finite-mass corrections. It is found that agreement on the order of 10^{-5} or better is obtained over most of the range of hard photon energies, at CMS energies relevant to both high energy collisions and radiative return experiments.

  19. Study of non-thermal photon production under different scenarios in solar flares. 2: The Compton inverse and Bremsstrahlung models and fittings

    Science.gov (United States)

    Perez-Peraza, J.; Alvarez, M.; Laville, A.; Gallegos, A.

    1985-01-01

    Energy spectra of photons emitted from Bremsstrahlung (BR) of energetic electrons with matter, is obtained from the deconvolution of the electron energy spectra. It can be inferred that the scenario for the production of X-rays and gamma rays in solar flares may vary from event to event. However, it is possible in many cases to associated low energy events to impulsive acceleration, and the high energy phase of some events to stochastic acceleration. In both cases, flare particles seem to be strongly modulated by local energy losses. Electric field acceleration, associated to neutral current sheets is a suitable candidate for impulsive acceleration. Finally, that the predominant radiation process of this radiation is the inverse Compton effect due to the local flare photon field.

  20. Electronic temperature measurement on the deca II plasma using the Bremsstrahlung; Mesure de la temperature electronique du plasma de deca II par etude du rayonnement de freinage

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-06-01

    The electronic temperature of the DECA II machine's plasma is determined by studying the Bremsstrahlung. Two types of detectors are used for this measurement, a set scintillator-photo-multiplicator and a photoelectric effect detector with a massive silver target. The method used is the classical 'absorbent method', The absorbents used are thin formvar foils whose thickness is between 600 and 12 500 angstrom. The measurements done in two different working conditions of the DECA II machine have given: Te {approx_equal} 200 eV in the first case and Te {approx_equal} 70 eV in the second case. (author) [French] Nous avons determine la temperature electronique du plasma de la machine DECA II par l'etude du rayonnement de freinage. Pour cette mesure nous avons utilise deux types de detecteurs: des ensembles scintillateur-photomultiplicateur et un detecteur a effet photoelectrique a cible massive en argent. La methode utilisee pour cette mesure est la classique methode des absorbants. Nous avons utilise des feuilles de format tres mince (de 600 a 12 500 angstrom) comme absorbant. Les mesures faites dans deux regimes de travail differents de la machine DECA II nous ont conduit a: Te {approx_equal} 200 eV dans un cas et Te {approx_equal} eV dans l'autre cas. (auteur)

  1. A measurement of the magnetic dipole moment of the. delta. /sup + +/(1232) from the bremsstrahlung process. pi. p. -->. pi. p. gamma

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.A.

    1987-06-01

    We have measured the cross section from the bremsstrahlung process ..pi../sup +/p ..-->.. ..pi../sup +/p..gamma.. for incident pions of energy 299 MeV. We detected the out going pion in the angular range from 55 to 95/sup 0/ in the lab, and photons were detected near 240/sup 0/ in the lab. We compare this measured cross-section to the MIT theory in order to extract a measurement of the magnetic dipole moment of the ..delta../sup + +/(1232), ..mu../sub ..delta../. In order to compare our results with the MIT theory, we have folded the MIT theory into the acceptance of our apparatus. We find that for pion angles between 55 and 75/sup 0/ the theory gives us a dipole moment of: 2.3..mu../sub p/ < ..mu../sub ..delta../ < 3.3..mu../sup p/ where the quoted error arises from an experimental uncertainty of +-0.25..mu../sub p/ and from theoretical uncertainties of +-0.25 ..mu../sub p/. However, for pion angles between 75 and 95/sup 0/ we find that the MIT theory predicts a cross-section which is larger than our measured cross-section, and makes it difficult to extract a value of ..mu../sub ..delta../. This over prediction is not understood, but consistent with a similar effect when the MIT theory is fit to previous data. 78 figs., 29 tabs.

  2. Coherent Bremsstrahlung, Coherent Pair Production, Birefringence and Polarimetry in the 20-170 GeV energy range using aligned crystals

    CERN Document Server

    Apyan, A; Badelek, B; Ballestrero, S; Biino, C; Birol, I; Cenci, P; Connell, S H; Eichblatt, S; Fonseca, T; Freund, A; Gorini, B; Groess, R; Ispirian, K; Ketel, T; Kononets, Y V; López, A; Mangiarotti, A; Sellschop, J P Friedel; Shieh, M; Sona, P; Strakhovenko, V M; Uggerhøj, U; Uggerhøj, Erik; Van Rens, B; Velasco, M; Vilakazi, Z Z; Wessely, O; Ünel, G; Kononets, Yu V

    2008-01-01

    The processes of coherent bremsstrahlung (CB) and coherent pair production (CPP) based on aligned crystal targets have been studied in the energy range 20-170 GeV. The experimental arrangement allowed these phenomena as well as their polarization dependence to be evaluated under conditions where single-photon cross-sections could be measured. This proved very important as the theoretical description of CB and CPP is an area of active theoretical debate and development. The theoretical approach used in this paper predicts both the cross sections and polarization observables very well for the experimental conditions investigated, indicating that the understanding of CB and CPP is reliable up to energies of 170 GeV. A birefringence effect in CPP was studied and it was demonstrated this enabled new technologies for high energy photon beam optics, such as polarimeters (for both linear and circular polarization) and phase plates. We also present new results regarding the features of coherent high energy photon emis...

  3. Brane Bremsstrahlung in DBI Inflation

    CERN Document Server

    Brax, Philippe

    2010-01-01

    We consider the effect of trapped branes on the evolution of a test brane whose motion generates DBI inflation along a warped throat. The coupling between the inflationary brane and a trapped brane leads to the radiation of non-thermal particles on the trapped brane. We calculate the Gaussian spectrum of the radiated particles and their backreaction on the DBI motion of the inflationary brane. Radiation occurs for momenta lower than the speed of the test brane when crossing the trapped brane. The slowing down effect is either due to a parametric resonance when the interaction time is small compared to the Hubble time or a tachyonic resonance when the interaction time is large. In both cases the motion of the inflationary brane after the interaction is governed by a chameleonic potential,which tends to slow it down. We find that a single trapped brane can hardly slow down a DBI inflaton whose fluctuations lead to the Cosmic Microwave Background spectrum. A more drastic effect is obtained when the DBI brane enc...

  4. Creation of high energy bremsstrahlung and intensity by a multitarget and refocusing of the scattered electrons by small-angle backscatter at the wall of a cone and magnetic fields

    CERN Document Server

    Ulmer, W

    2011-01-01

    The yield of bremsstrahlung from collisions of fast electrons (energy at least 6 MeV) with a tungsten target can be significantly improved by exploitation of Tungsten wall scatter in a multi-layered target. The Tungsten wall can serve to refocuse small angle scattered electrons. It is necessary that the thickness of one Tungsten layer does not exceed 0.02 mm. Further refocusing of electrons results from suitable magnetic fields with field strength between 0.5 Tesla and 6 Tesla (if the cone with multi-layered targets is rather narrow). Linear accelerators in radiation therapy only need refocusing by wall scatter without further magnetic fields (standard case: ca. 100 - 000 plates with 0.01 mm thickness and 1 mm distance between the plates). The construction of a very narrow bremsstrahlung beam with extremely high photon intensity requires an additional strong magnetic field (order 1 - 6 Tesla), which provides the possibility to check Heisenberg-Euler scatter of high energy photons.

  5. Giant dipole resonance decay and bremsstrahlung emission as a source of high-energy gamma-rays in sup 1 sup 2 C+ sup 2 sup 4 sup , sup 2 sup 6 Mg and sup 1 sup 2 C+ sup 5 sup 8 sup , sup 6 sup 4 Ni reactions at 6-11 MeV/u

    CERN Document Server

    Kicinska-Habior, M; Maj, A; Kelly, M P; Schagen, J P S; Snover, K A

    1999-01-01

    It is shown that in the mass-asymmetric reactions, sup 1 sup 2 C+ sup 2 sup 4 sup , sup 2 sup 6 Mg and sup 1 sup 2 C+ sup 5 sup 8 sup , sup 6 sup 4 Ni, at E sub p /A = 6-11 MeV/u, the two types of gamma-ray emission, statistical GDR decay and bremsstrahlung radiation, may be disentangled using angular distribution measurements. The analyzed data give information on the GDR built on excited states as well as on the bremsstrahlung process. The extracted GDR parameters and bremsstrahlung parameters for sup 1 sup 2 C+ sup 2 sup 4 sup , sup 2 sup 6 Mg are in general in agreement with the systematics. However, the inverse slope parameter, E sub 0 , depends on gamma-ray energy and as a result the bremsstrahlung cross-section at low and high E subgamma energies is lower than expected for constant E sub 0 value.

  6. Large momentum transfer scattering and hadronic bremsstrahlung

    CERN Document Server

    Blankenbecler, Richard

    1975-01-01

    The interchange theory provides a simple picture of large momentum transfer scattering which correlates many features of hadrons and their interactions. It is simple to compute and has considerable predictive power. It unites the electromagnetic structure of hadrons as expressed through their form factors and inelastic structure functions with elastic and inelastic hadron-hadron scattering. The theory joins smoothly onto Regge behavior which controls forward scattering and in fact predicts such behaviour. The unified description of large and small momentum transfer scattering provided by the interchange model should allow considerable insight into the interaction of hadrons and their possible composite nature. It already yields a remarkably simple quantitative description which seems valid all the way from large angle elastic scattering at 5 GeV/c to inclusive scattering at the CERN-ISR. (13 refs).

  7. Radiative Corrections to Bremsstrahlung in Radiative Return

    CERN Document Server

    Yost, S A; Ward, B F L; Yost, Scott A.

    2005-01-01

    Radiating a photon from the initial state provides a useful tool for studying a range of low energy physics using a high-energy e+ e- accelerator. Accurate results require careful calculation of the first order virtual photon corrections. We compare exact results for initial state radiative corrections, finding agreement to an order of 10^{-5} or better as a fraction of the Born cross-section for most of the range of photon energies, at CMS energies relevant in both high-energy collision and radiative return experiments.

  8. Electron bremsstrahlung angular-distribution fits for atomic numbers 1 less than or equal to Z less than or equal to 92, and incident-electron energies 1 keV less than or equal to T less than or equal to 500 keV

    Energy Technology Data Exchange (ETDEWEB)

    Kissel, L.

    1982-01-01

    The analytic fit of a simple expression to the electron bremsstrahlung angular distribution cross section d/sup 2/sigma/dkd..cap omega.. (differential in the emitted photon energy k and angle ..cap omega..) is investigated. Optimal choices for the fit parameters are determined and fit coefficients are tabulated for a large number of neutral-atom cases. Results are also presented for fits to the relativistic Coulomb-Born approximation. Comparisons between the screened neutral-atom results and the Coulomb-Born results are made. Discrepancies reported to exist between angular distribution cross sections and fit coefficients published by Tseng, Pratt and Lee are confirmed and understood in terms of their choice of fit weight function.

  9. Bremsstrahlung analysis through the microwave cutoff and afterglow performances

    CERN Document Server

    Lamoureux, M P; Niimura, M; Kidera, M; Nakagawa, T

    1999-01-01

    Bremsstralung spectra with a very good energy resolution have been obtained for various time slabs of a few ms throughout the microwave cutoff. In a recent work (1) we had noticed+ and explained why the enhancement of the extracted high charge currents by the afterglow effect is more pronounced when the X-ray emission in the heating stage is more intense. In the present communication, we give some additional information deduced from our spectra. We indicate estimates of the temperature parameter and of the density of the hot electron population at various times. For this purpose the method presented in ref.(3) was adapted to argon. We also determine the maximum energy reached by the electrons in the steady state; the spare results seem to follow the scaling law indicated in Geller's book (4).

  10. Decay energy of Fe from its inner Bremsstrahlung spectrum

    Indian Academy of Sciences (India)

    the emission of a continuous spectrum of electromagnetic radiation. ... Coulomb effect. Martin and Glauber (MG) [3] worked out a theory taking into account the relativistic effects and all the electrostatic effects around the nucleus. .... Бib either positive or negative towards the end of the energy spectrum, wherenil counts are.

  11. Electromagnetic off-shell effects in proton-proton bremsstrahlung

    NARCIS (Netherlands)

    Kondratyuk, S.A.; Martinus, G.H.; Scholten, O.

    1998-01-01

    We study the influence of the off-shell structure of the nucleon electromagnetic vertex on proton-proton bermsstrahlung observables. Realistic choices for the off-shell behavior are found to have considerable influences on observables such as cross sections and analyzing powers. The rescattering

  12. Field-enhanced REB deposition and Bremsstrahlung production

    Energy Technology Data Exchange (ETDEWEB)

    Halbleib, J.A. Sr.; Widner, M.M.

    1977-07-01

    Recently developed models are employed to describe the interaction of a high-current REB (relativistic electron beam) with planar gold foils in the presence of macroscopic electromagnetic fields. It is shown that, under certain conditions, azimuthal magnetic fields which either penetrate into the foil and/or exist on the transmission side of the foil can significantly enhance the specific power deposited in the foil over that which would be deposited for diode fields alone. Similar field effects suggest methods for improving the external conversion efficiencies, softening the spectra and focussing the source intensities of flash x-ray facilities. Finally, preliminary results are shown from a new trajectory-field model for self-consistent REB transport.

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

    Indian Academy of Sciences (India)

    [13] Mars Semaan and C A Quarles, X-ray Spectrom. 30, 37 (2001). [14] A N Agnihotri, V S Subrahmanyam, R K Yadav, R Shanker and X Llovet, J. Phys. D: Appl. Phys. 41, 065205 (2008). [15] F Salvat, J M Fernández-Varea and J Sempau, PENELOPE-2006: A code sys- tem for Monte Carlo simulation of electron and ...

  14. Note on Inverse Bremsstrahlung in a Strong Electromagnetic Field

    Science.gov (United States)

    Bethe, H. A.

    1972-09-01

    The collisional energy loss of an electron undergoing forced oscillation in an electromagnetic field behaves quite differently in the low and high intensity limits. ... It is shown that in the case of an electromagnetic field v {sub o} >> v {sub t} the rate of transfer is much slower, and actually decreases with the strength of the field.

  15. Bremsstrahlung photons as a probe of hot nuclei

    NARCIS (Netherlands)

    MARTINEZ, G; MARQUES, FM; SCHUTZ, Y; WOLF, G; DIAZ, J; FRANKE, M; HLAVAC, S; HOLZMANN, R; LAUTRIDOU, P; LEFEVRE, F; Löhner, H.; MARIN, A; MATULEWICZ, T; MITTIG, W; OSTENDORF, RW; VANPOL, JHG; QUEBERT, J; ROUSSELCHOMAZ, P; SCHUBERT, A; SIEMSSEN, RH; SIMON, RS; SUJKOWSKI, Z; WAGNER, [No Value; WILSCHUT, HW

    1995-01-01

    Aside from the dominant production of hard photons in first-chance p-n collisions, a significant hard-photon production in a later stage of heavy-ion reactions is predicted by the BUU theory. These thermal hard photons are emitted from a nearly thermalized source and still originate from

  16. Proton-proton bremsstrahlung and elastic nucleon-nucleon scattering : relativistic formulations

    NARCIS (Netherlands)

    Cozma, Mircea Dan

    2004-01-01

    De studie van de sterke wisselwerking tussen kerndeeltjes (nucleonen, dat wil zeggen protonen en neutronen) is binnen de kernfysica een actief onderzoeksveld geweest vanaf de vroege jaren dertig van de vorige eeuw. Sinds ongeveer 30 jaar weten we dat de fundamentele theorie van de sterke

  17. 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.

  18. 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 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.

  19. Application of calorimeters for 5 MeV EB and bremsstrahlung dosimetry

    DEFF Research Database (Denmark)

    Sato, T.; Takahashi, T.; Saito, T.

    1993-01-01

    Graphite and water calorimeters, which were developed for use a 10 MeV electron beams (EB) at Riso National Laboratory, were used for process validation and routine dosimeter calibration at a 5 MeV EB. Water calorimeters were used for reference measurements for 5 MeV EB, the response was found...... at 5 MeV EB. Graphite calorimeters gave reproducible readings within 3.3 % relative errors (95 % confidence level) for X-ray measurement....

  20. Linear microfocus bremsstrahlung generated in light and heavy narrow targets in B-18 betatron

    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'kovskii, I. K.

    2017-08-01

    The first results of studying the properties of X- and G-ray beams generated at the grazing incidence of 18-MeV electrons with the 50 and 8-μm-thick Si crystals and a 13-μm-thick Ta foil of 4 mm in length along the electron beam are presented. The target has been placed in a goniometer inside the chamber of a B-18 betatron. The results exhibit strong changes in the angular distribution of radiation at the variation of the orientation of the target. This effect is not observed in the case of the normal incidence of electrons on the surface of a thin target. Images of a reference microstructure have been obtained with a high resolution of details of the microstructure owing to the smallness of the source of radiation. The dependence of the contrast of an image on the position of the microstructure in the radiation cone has been demonstrated, which is determined by the change in the effective size of the radiation source when the emission angle of the source is changed.

  1. Proof of Principle for Active Detection of Fissionable Material Using Intense, Pulsed-Bremsstrahlung-Induced Photofission

    Science.gov (United States)

    2014-10-07

    22202-4302. Respondents should be aware that notwithstanding any other provision of law , no person shall be subject to any penalty for failing to...experiments,” J. Appl. Phys., vol. 50, no. 6, pp. 3928-3934, June 1979. 32. C.W. Mendel , “Planar one-dimensional magnetically insulated electron flow...for arbitrary canonical-momentum distribution,” J. Appl. Phys., vol. 50, no. 6, pp.3830-3837, June 1979. 33. C.W. Mendel , D.B. Seidel, and S.E

  2. Quasifree bremsstrahlung in the dp-->dpγ reaction above the pion production threshold

    Science.gov (United States)

    Greiff, J.; Koch, I.; Scobel, W.; Rohdjeß, H.; Dyring, J.; Fransson, K.; Gustafsson, L.; Häggström, S.; Höistad, B.; Johanson, J.; Johansson, A.; Johansson, T.; Khoukaz, A.; Kullander, S.; Ruber, R. J.; Złomańczuk, J.; Dunin, V.; Morosov, B.; Sukhanov, A.; Zernov, A.; Stepaniak, J.; Bilger, R.; Brodowski, W.; Clement, H.; Wagner, G. J.; Calén, H.; Ekström, C.; Kupść, A.; Marciniewski, P.; Zabierowski, J.; Shwartz, B.; Sukhanov, A.; Oelert, W.; Sefzick, T.; Turowiecki, A.

    2002-03-01

    Experimental results of the dp-->dpγ reaction are presented for several observables with deuteron projectile energies between 437 MeV and 559 MeV. The kinematically complete measurements were performed at the CELSIUS storage ring with the PROMICE/WASA setup. Angular and spectral distributions of the charged ejectiles are decomposed into fractions that can be attributed to a quasifree np-->dγ process with a spectator proton and to a process involving all three nucleons. Within the acceptance of the detector, about two thirds of the events are associated to the quasifree process; the remainder are characterized by substantial transverse momentum components transferred to a participating outgoing proton.

  3. Bremsstrahlung function, leading Lüscher correction at weak coupling and localization

    Energy Technology Data Exchange (ETDEWEB)

    Bonini, Marisa; Griguolo, Luca; Preti, Michelangelo [Dipartimento di Fisica e Scienze della Terra,Università di Parma and INFN Gruppo Collegato di Parma,Viale G.P. Usberti 7/A, 43100 Parma (Italy); Seminara, Domenico [Dipartimento di Fisica, Università di Firenze and INFN Sezione di Firenze,via G. Sansone 1, 50019 Sesto Fiorentino (Italy)

    2016-02-26

    We discuss the near BPS expansion of the generalized cusp anomalous dimension with L units of R-charge. Integrability provides an exact solution, obtained by solving a general TBA equation in the appropriate limit: we propose here an alternative method based on supersymmetric localization. The basic idea is to relate the computation to the vacuum expectation value of certain 1/8 BPS Wilson loops with local operator insertions along the contour. These observables localize on a two-dimensional gauge theory on S{sup 2}, opening the possibility of exact calculations. As a test of our proposal, we reproduce the leading Lüscher correction at weak coupling to the generalized cusp anomalous dimension. This result is also checked against a genuine Feynman diagram approach in N=4 Super Yang-Mills theory.

  4. An Investigation of Bremsstrahlung Reflection in a Dense Plasma Focus Device

    Science.gov (United States)

    2006-03-01

    CO 80840 Mr. Yoshinari Minami (1 CD) NEC Patent Service, Morinaga Plaza Bldg. 18F,33-1, Shiba 5- Chome , Minato-Ku , Tokyo 108-8425 Japan Mr...Kimo Nishino (1 CD) Toyota Motor Corp. 23-22 IZUMI, 1 CHOME HIGASHI-KU, NAGOYA 461-8711 Japan Dr. Kenneth G. Moses (1 CD) Fusion Physics 3547

  5. Comparison of analytical and Monte Carlo calculations of multi-photon effects in bremsstrahlung emission by high-energy electrons

    DEFF Research Database (Denmark)

    Mangiarotti, Alessio; Sona, Pietro; Ballestrero, Sergio

    2012-01-01

    Approximate analytical calculations of multi-photon effects in the spectrum of total radiated energy by high-energy electrons crossing thin targets are compared to the results of Monte Carlo type simulations. The limits of validity of the analytical expressions found in the literature are establi...

  6. Effects of initial electron beam parameters of a linear accelerator on the properties of bremsstrahlung radiation in a radiotherapy setting

    Science.gov (United States)

    Gorlachev, G. E.; Polozov, S. M.; Dalechina, A. V.; Ksenofontov, A. I.; Kistenev, A. V.

    2016-12-01

    The dependence of the initial electron-beam parameters on absorbed dose distributions have been investigated using a CyberKnife radiotherapy accelerator (Accuray, United States). To describe the initial electron-beam characteristics, simulations of the linear electron accelerator are performed and the electron distributions in the beam of a linac output are analyzed. The radial distributions of electrons are assumed exponential, whereas the energy electron distributions are approximated by monoenergetic and rectangular spectra. There is no significant dependence of depth-dose curves in a phantom on the shape of the electron beam. Importantly, a clear dependence of the radiation field profile on the size of the electron beam is observed not just in the penumbra region, but also in the open part.

  7. Isomeric ratios in photonuclear reactions of molybdenum isotopes induced by bremsstrahlung in the giant dipole resonance region

    Science.gov (United States)

    Thiep, Tran Duc; An, Truong Thi; Cuong, Phan Viet; Vinh, Nguyen The; Hue, Bui Minh; Belov, A. G.; Maslov, O. D.; Mishinsky, G. V.; Zhemenik, V. I.

    2017-01-01

    We have determined the isomeric ratios of isomeric pairs 97m,gNb, 95m,gNb and 91m,gMo produced in 98Mo(γ, p)97m,gNb, 96Mo(γ, p)95m,gNb and 92Mo(γ, n)91m,gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for 97m,gNb from 14 to 19 MeV, for 195m,gNb from14 to 24 MeV except 20 and 23.5 MeV and for 91m,gMo at 14 and 15 MeV are the first time measurements.

  8. Study of an efficient application of the tagged bremsstrahlung in double-polarization experiments in the GeV range and the use of the inelastic electron scattering under extremely forward angles as alternative to the tagged bremsstrahlung; Studie eines effizienten Einsatzes der markierten Bremsstrahlung bei Doppelpolarisationsexperimenten im GeV-Bereich und der Nutzung der inelastischen Elektronstreuung unter extremen Vorwaertswinkeln als Alternative zur markierten Bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, M.

    2006-03-15

    For the preparation of photonic probes for hadron physics the determination of energy and polarization of the photons is essential. In this dissertation in a first part a possibility of the determination of the degree of polarization by use of the asymmetry observables is presented. In a second part a possibility isd discussed to perform an energy and polarization tagging of nearly real photons in electron scattering under small Q{sup 2}. By this method it should be possible to tag billions of photons per second.

  9. Thermal limits on MV x-ray production by bremsstrahlung targets in the context of novel linear accelerators.

    Science.gov (United States)

    Wang, Jinghui; Trovati, Stefania; Borchard, Philipp M; Loo, Billy W; Maxim, Peter G; Fahrig, Rebecca

    2017-12-01

    To study the impact of target geometrical and linac operational parameters, such as target material and thickness, electron beam size, repetition rate, and mean current on the ability of the radiotherapy treatment head to deliver high-dose-rate x-ray irradiation in the context of novel linear accelerators capable of higher repetition rates/duty cycle than conventional clinical linacs. The depth dose in a water phantom without a flattening filter and heat deposition in an x-ray target by 10 MeV pulsed electron beams were calculated using the Monte-Carlo code MCNPX, and the transient temperature behavior of the target was simulated by ANSYS. Several parameters that affect both the dose distribution and temperature behavior were investigated. The target was tungsten with a thickness ranging from 0 to 3 mm and a copper heat remover layer. An electron beam with full width at half maximum (FWHM) between 0 and3 mm and mean current of 0.05-2 mA was used as the primary beam at repetition rates of 100, 200, 400, and 800 Hz. For a 10 MeV electron beam with FWHM of 1 mm, pulse length of 5 μs, by using a thin tungsten target with thickness of 0.2 mm instead of 1 mm, and by employing a high repetition rate of 800 Hz instead of 100 Hz, the maximum dose rate delivered can increase two times from 0.57 to 1.16 Gy/s. In this simple model, the limiting factor on dose rate is the copper heat remover's softening temperature, which was considered to be 500°C in our study. A high dose rate can be obtained by employing thin targets together with high repetition rate electron beams enabled by novel linac designs, whereas the benefit of thin targets is marginal at conventional repetition rates. Next generation linacs used to increase dose rate need different target designs compared to conventional linacs. © 2017 American Association of Physicists in Medicine.

  10. Simulation of delayed γ-ray emission following photofission reactions induced by pulsed bremsstrahlung x-rays using MCNPX and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Xianfei, E-mail: wenxianfei@ufl.edu [Nuclear Engineering Program, University of Florida, Gainesville, FL 32611 (United States); School of Nuclear Science and Engineering, Oregon State University, Corvallis, OR 97331 (United States); Yang, Haori, E-mail: haori.yang@oregonstate.edu [School of Nuclear Science and Engineering, Oregon State University, Corvallis, OR 97331 (United States)

    2016-12-21

    There is a great demand to develop non-destructive techniques to identify and quantify Special Nuclear Materials (SNM) in homeland security and nuclear safeguards applications. Passive assay could be extremely challenging in some scenarios. Active interrogation technique based on photofission has been identified as one of the promising approaches. In radiation detection system design based on such technique, it is highly desired to have abilities to accurately and efficiently simulate delayed γ-rays emitted from photofission reactions. In this work, simulation results were compared with measurement outcomes to demonstrate the capabilities and limitations of the code MCNPX 2.7.0 in the simulation of delayed γ-rays from photofission of uranium and plutonium samples. First, high-energy delayed γ-rays (E{sub γ}~2.7–4.5 MeV) from photofission of {sup 238}U were simulated and validated against the energy spectra measured in between linac pulses. Second, low-energy delayed γ-ray spectra (E{sub γ}~0.6–2.7 MeV) measured with a list-mode system after irradiation of {sup 239}Pu were used in the validation.

  11. Study of radionuclides created by {sup 181}Ta({gamma},xn yp) reactions for bremsstrahlung photons produced by 150-MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.A. [Wisconsin Univ., River Falls, WI (United States); Dickens, J.K. [Oak Ridge National Lab., TN (United States)

    1991-12-01

    Ten radionuclides, including isomers, from {sup 172}Ta to {sup 180}Ta and {sup 180m}Hf were produced by photon interactions with a sample of elemental tantalum and measured by counting photons using a high-resolution detection system. Relative yields of these radionuclides were obtained. In addition, precision half lives were obtained for {sup 175,176,180}Ta and {sup 180m}Hf. Those obtained for the three Ta isotopes agree with previously reported values. For {sup 180m}Hf, the present measurements resulted in a half life determination of 6.05{plus_minus}0.06 hr, or about 10% longer than the currently adopted value for this half life.

  12. Study of radionuclides created by sup 181 Ta(. gamma. ,xn yp) reactions for bremsstrahlung photons produced by 150-MeV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.A. (Wisconsin Univ., River Falls, WI (United States)); Dickens, J.K. (Oak Ridge National Lab., TN (United States))

    1991-12-01

    Ten radionuclides, including isomers, from {sup 172}Ta to {sup 180}Ta and {sup 180m}Hf were produced by photon interactions with a sample of elemental tantalum and measured by counting photons using a high-resolution detection system. Relative yields of these radionuclides were obtained. In addition, precision half lives were obtained for {sup 175,176,180}Ta and {sup 180m}Hf. Those obtained for the three Ta isotopes agree with previously reported values. For {sup 180m}Hf, the present measurements resulted in a half life determination of 6.05{plus minus}0.06 hr, or about 10% longer than the currently adopted value for this half life.

  13. Energy loss, range, and bremsstrahlung yield for 10-keV to 100-MeV electrons in various elements and chemical compounds

    Science.gov (United States)

    Pages, Lucien; Bertel, Evelyne; Joffre, Henri; Sklavenitis, Laodamas

    2012-12-01

    Even though the United States lacks a national climate policy, significant action has occurred at the local and regional levels. Some of the most aggressive climate change policies have occurred at the state and local levels and in interagency cooperation on specific management issues. While there is a long history of partnerships in dealing with a wide variety of policy issues, the uncertainty and the political debate surrounding climate change has generated new challenges to establishing effective policy networks. This paper investigates the formation of climate policy networks in the State of Nevada. It presents a methodology based on social network analysis for assessing the structure and function of local policy networks across a range of substantive climate impacted resources (water, landscape management, conservation, forestry and others). It draws from an emerging literature on federalism and climate policy, public sector innovation, and institutional analysis in socio-ecological systems. Comparisons across different policy issue networks in the state are used to highlight the influence of network structure, connectivity, bridging across vertical and horizontal organizational units, organizational diversity, and flows between organizational nodes.

  14. Simulation of delayed γ-ray emission following photofission reactions induced by pulsed bremsstrahlung x-rays using MCNPX and experimental validation

    Science.gov (United States)

    Wen, Xianfei; Yang, Haori

    2016-12-01

    There is a great demand to develop non-destructive techniques to identify and quantify Special Nuclear Materials (SNM) in homeland security and nuclear safeguards applications. Passive assay could be extremely challenging in some scenarios. Active interrogation technique based on photofission has been identified as one of the promising approaches. In radiation detection system design based on such technique, it is highly desired to have abilities to accurately and efficiently simulate delayed γ-rays emitted from photofission reactions. In this work, simulation results were compared with measurement outcomes to demonstrate the capabilities and limitations of the code MCNPX 2.7.0 in the simulation of delayed γ-rays from photofission of uranium and plutonium samples. First, high-energy delayed γ-rays (Eγ 2.7-4.5 MeV) from photofission of 238U were simulated and validated against the energy spectra measured in between linac pulses. Second, low-energy delayed γ-ray spectra (Eγ 0.6-2.7 MeV) measured with a list-mode system after irradiation of 239Pu were used in the validation.

  15. Sensitivity analysis of the influence of the medium energy and initial fluence FWHM of electron determining a Bremsstrahlung photon spectrum of a linear accelerator; Analisis de sensibilidad de la influencia de la energia media FWHM de la influencia inicial de electrones en la determinacion de un espectro de fotones Bremsstrahlung de un acelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Juste, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2012-11-01

    A correct dose calculation in patient under radiotherapy treatments requires and accurate description of the radiation source. The main goal of the present work is to study the effects of initial electron beam characteristics on Monte Carlo calculated absorbed dose distribution for a 6 MeV linac photon beam. To that, we propose a methodology to determine the initial electron fluence before hitting the accelerator target for an Elektra Precis a medical linear accelerator. The method used for the electron radiation source description is based on a Software for Uncertainty and Sensitivity Analysis (SUSA) and Monte Carlo simulations using the MCNP5 transport code. This electron spectrum has been validated by means of comparison of its resulting depth dose curve in a water cube with experimental data being the mean difference below the 1%. (Author)

  16. Sensitivity analysis the influence of the average energy and FWHM of the initial fluence electrons in the determination of a spectrum of photons Bremsstrahlung of a linear accelerator; Analisis de sensibilidad de la influencia de la energia media y FWHM de la fluencia inicial de electrones en la determinacion de un espectro de fotones Bremsstrahlung de accelerador lineal

    Energy Technology Data Exchange (ETDEWEB)

    Justo, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.

    2011-07-01

    The main objective of this work is to study the effects of the initial beam characteristics of electrons in the absorbed dose distribution calculated by Monte Carlo for a photons beam of 6 MeV emitted by a medical linear accelerator.

  17. Unoccupied density of states of La2–xSrxNiO4+δ studied by polarization-dependent x-ray-absorption spectroscopy and bremsstrahlung isochromat spectroscopy

    NARCIS (Netherlands)

    Kuiper, P.; Elp, J. van; Sawatzky, G.A.; Fujimori, A.; Hosoya, S.; Leeuw, D.M. de

    1991-01-01

    Oxygen 1s x-ray-absorption measurements of La2–xSrxNiO4+δ (0≤x≤1.15) are presented, together with O 1s polarization-dependent x-ray absorption on single-crystal La1.85Sr0.15NiO4. It is concluded that the charge-compensating holes have mainly oxygen 2p character. The Ni 3d9 final states reached

  18. Isomeric yield ratios for the {sup nat}Ag(γ,xn){sup 106m,g;104m,g}Ag photonuclear reactions induced by 40-, 45-, 50-, 55-, and 60-MeV bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Van Do, Nguyen; Duc Khue, Pham; Tien Thanh, Kim; Hien, Nguyen Thi [Institute of Physics, Vietnam Academy of Science and Technology,10 Dao Tan, Hanoi (Viet Nam); Van Loat, Bui [College of Science, Vietnam National University, Hanoi, 334 Nguyen Trai Str., Hanoi (Viet Nam); Yang, Sung-Chul [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Nuclear Data Center, Korea Atomic Energy Research Institute, Dajeon 305-353 (Korea, Republic of); Kim, Kwangsoo [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Guinyun, E-mail: gnkim@knu.ac.kr [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Song, Tae-Young [Nuclear Data Center, Korea Atomic Energy Research Institute, Dajeon 305-353 (Korea, Republic of); Shin, Sung-Gyun; Cho, Moo-Hyun; Kye, Yong-Uk [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Man-Woo [Research Center, Dongnam Institute of Radiological and Medical Science, Busan 619-953 (Korea, Republic of)

    2015-01-01

    We have determined the isomeric yield ratios for the isomeric pairs {sup 106m,g}Ag and {sup 104m,g}Ag produced on natural silver target nuclei in the bremstrahlung energy region from 40- to 60-MeV. The measurements were carried out by the activation method in combination with direct γ-spectrometry. The necessary corrections were made to improve the accuracy of the experimental results. The present yield ratios measured at 40, 45, 50, 55, and 60 MeV for the {sup 106m,g}Ag isomeric pair are 0.019 ± 0.002, 0.022 ± 0.002, 0.023 ± 0.002, 0.025 ± 0.002, and 0.025 ± 0.002, and those for the {sup 104m,g}Ag isomeric pair are 1.26 ± 0.12, 1.34 ± 0.12, 1.36 ± 0.12, 1.43 ± 0.12, and 1.49 ± 0.12, respectively. The obtained results are compared with those existing in literature and discussed.

  19. Low-energy cosmic rays in the Orion region

    DEFF Research Database (Denmark)

    Pohl, M.

    1998-01-01

    on the general structure of the interstellar medium. We propose an independent test for the existence of LECR by observing the inverse bremsstrahlung and secondary bremsstrahlung of these nucleons. The expected X-ray photon flux scales to the gamma-ray photon flux with the ratio of the corresponding cross...

  20. HARD PHOTONS AS A PROBE TO STUDY DISSIPATION MECHANISMS

    NARCIS (Netherlands)

    VANPOL, JHG; BALLESTER, F; DIAZ, J; FRANKE, M; HLAVAC, S; HOLZMANN, R; KUHN, W; KUGLER, A; LAUTRIDOU, P; LEFEVRE, F; LOHNER, H; MARIN, A; MARQUES, M; MARTINEZ, G; MATULEWICZ, T; MITTIG, W; NOTHEISEN, M; NOVOTNY, R; OSTENDORF, RW; ROUSSELCHOMAZ, P; SIEMSSEN, RH; SCHUBERT, A; SCHUTZ, Y; SIMON, RS; WAGNER, [No Value; WILSCHUT, HW

    1995-01-01

    The probability for Bremsstrahlung has been measured as function of the mass of the projectile-like fragment in peripheral reactions of Ar-36 + Tb-159 at 44 MeV/nucleon. The Bremsstrahlung probability is found to depend on the amount of mass transferred and the direction of the transfer.

  1. Transmutation of sup 2 sup 0 sup 4 Pb in an intensive gamma-ray flux

    CERN Document Server

    Ishkhanov, B S

    2001-01-01

    Transmutation chain formation during irradiation with various intensities of bremsstrahlung photon beam is analysed. The main features of transmutation chain formation by photons with energies corresponding to the giant dipole resonance are discussed.

  2. Prospects for Photon-Photon and Photon-Proton Measurements with Forward Proton Taggers in ATLAS

    CERN Document Server

    Trzebinski, Maciej; The ATLAS collaboration

    2017-01-01

    Talk for Photon2017 conference. Topics covered: ALFA and AFP detectors. Physics: elastic scattering, diffractive bremsstrahlung, exclusive pion pair production, anomalous gauge couplings, new physics (e.g. magnetic monopoles).

  3. On the Nature of the Gamma-ray Bursts

    Directory of Open Access Journals (Sweden)

    Kyung-Ai Hong

    1987-12-01

    Full Text Available Review of the γ-ray burst phenomena are presented. History of the γ-ray bursts, characteristics, and three radiation mechanisms of thermal bremsstrahlung, thermal synchrotron, and inverse Compton scattering processes are considered.

  4. ANALYSIS OF X-RAY SPECTRA EMITTED FROM THE VENUS ECR ION SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, J.; Leitner, D.

    2008-01-01

    The Versatile Electron Cyclotron resonance ion source for Nuclear Science (VENUS), located at Lawrence Berkeley National Lab’s 88-inch cyclotron, extracts ion beams from a plasma created by ionizing a gas with energetic electrons. Liquid-helium cooled superconducting coils produce magnetic fi elds that confi ne the plasma and high microwave frequencies heat the electrons enough to allow for successive ionizations of the neutral gas atoms. The combination of strong plasma confi nement and high microwave frequencies results in VENUS’ production of record breaking ion beam currents and high charge state distributions. While in operation, VENUS produces signifi cant quantities of bremsstrahlung, in the form of x-rays, primarily through two processes: 1) electron-ion collisions within the plasma, and 2) electrons are lost from the plasma, collide with the plasma chamber wall, and radiate bremsstrahlung due to their sudden deceleration. The bremsstrahlung deposited into the plasma chamber wall is absorbed by the cold mass used to maintain superconductivity in the magnets and poses an additional heat load on the cryostat. In order for VENUS to reach its maximum operating potential of 10 kW of 28 GHz microwave heating frequency, the heat load posed by the emitted bremsstrahlung must be understood. In addition, studying the bremsstrahlung under various conditions will help further our understanding of the dynamics within the plasma. A code has been written, using the Python programming language, to analyze the recorded bremsstrahlung spectra emitted from the extraction end of VENUS. The code outputs a spectral temperature, which is relatively indicative of the temperature of the hot electrons, and total integrated count number corresponding to each spectra. Bremsstrahlung spectra are analyzed and compared by varying two parameters: 1) the heating frequency, 18 GHz and 28 GHz, and 2) the ratio between the minimum magnetic fi eld and the resonant magnetic fi eld, .44 and

  5. Treatment of the electrons-photons cascade in the high energy gamma transport; Traitement de la cascade electrons - photons dans le transport des gammas de haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Riz, D

    1999-10-01

    The electrons-photons cascade is an important phenomena occurring in gamma transport. This phenomena called also Bremsstrahlung happens whenever electrons, produced in a photon-atom interaction, trigger emission of photons while slowing down in the matter. Some previous calculations have shown that in particular circumstances, a flux of photons going through a lead plate can be multiplied by 3 when Bremsstrahlung is taken into account. This work is dedicated to a new method developed in CEA to take into account Bremsstrahlung in any gamma transport code using multigroup constants. An electron or a positron produced by an incident photon {gamma} will move till it has lost all its energy in collisions or in emissions of Bremsstrahlung {gamma}'. The path of the electron is short so all the Bremsstrahlung {gamma}' are assumed to be produced at the point of creation of the electron or positron. The result of this method is the knowledge of a transfer probability {gamma}{yields}{gamma}' that can be used in classical gamma transport codes. (A.C.)

  6. Development of a virtual Z(eff) diagnostic for the W7-X stellarator.

    Science.gov (United States)

    Krychowiak, M; Dodt, D; Dreier, H; König, R; Wolf, R

    2008-10-01

    For the W7-X stellarator a diagnostic system for measurement of local Z(eff) values from the visible bremsstrahlung continuum is foreseen. The method is based on passive, absolute measurement of the bremsstrahlung intensity along several lines of sight. In order to eliminate the spurious impact of other radiation sources of different spectral intensity distribution than the bremsstrahlung, like the line radiation, it is intended to spectrally resolve the detected radiation, e.g., by use of microspectrometers. The visible bremsstrahlung background can be extracted by making use of the 1/lambda(2) dependence of its intensity (expressed in unit Wm(3) sr nm) in the high temperature plasmas by using Bayesian data analysis techniques. In a second step, the local values of Z(eff) as a function of the effective plasma radius are derived by inversion, using different regularization methods, of the line-integrated bremsstrahlung signals with the knowledge of the magnetic flux surfaces. Inversion of the full model based on statistical methods allows taking into account all conceivable uncertainties accompanying Z(eff) measurement and provides uncertainties of the local Z(eff) values and valuable information on other uncertain parameters of the model. In this paper we show the first steps in developing a virtual Z(eff) diagnostic for W7-X which allows the optimization of the statistical model as well as of the future diagnostic setup.

  7. Numerical simulation of laser fusion plasmas using a reduced description formalism

    Energy Technology Data Exchange (ETDEWEB)

    Faehl, R.J.

    1976-12-01

    A computational study of laser fusion plasmas with a new numerical model is undertaken. The plasma is described by fluid equations and the fields by the time dependent Maxwell's equations. Problems of stimulated Brillouin scattering, self-steepening of the critical surface, wave trapping near the critical surface, and competition of inverse bremsstrahlung absorption with Brillouin scattering are treated to demonstrate the flexibility of the model. New results are obtained for intensity-dependent inverse bremsstrahlung absorption. Absorption of laser energy via density fluctuations in the underdense plasma is discussed and studied numerically for assumed fluctuation distributions.

  8. Magnifying Lenses with Weak Achromatic Bends for High-Energy Electron Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Walstrom, Peter Lowell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-27

    This memo briefly describes bremsstrahlung background effects in GeV-range electron radiography systems and the use of weak bending magnets to deflect the image to the side of the forward bremsstrahlung spot to reduce background. The image deflection introduces first-order chromatic image blur due to dispersion. Two approaches to eliminating the dispersion effect to first order by use of magnifying lens with achromatic bends are described. Also, higher-order image blur terms caused by weak bends are also discussed, and shown to be negligibly small in most cases of interest.

  9. Tests of a High Resolution Beam Profile Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Norem, J.

    2004-10-28

    High energy linear colliders require very small beams at the interaction point to produce high luminosities, and these beams must be measured and monitored. We have developed and tested a technique where the profile can be obtained from an extension of pinhole camera optics using thick, single sided collimators and slits. Very high resolutions (a few nm) should be possible. Gamma beams can be obtained from bremsstrahlung, Compton or beamstrahlung radiation. We describe tests of the technique using bremsstrahlung from an 800 MeV electron beam at Bates/MIT, Compton scattered photons from 47 GeV Final Focus Test Beam (FFTB) at SLAC, and other applications, such as linear colliders.

  10. X-ray radiography for testing wood structure

    Energy Technology Data Exchange (ETDEWEB)

    Musyankov, S.I. (Nauchno-Issledovatel' skij Inst. Introskopii, Moscow (USSR))

    1983-01-01

    Experimental and calculation values of the attenuation factor of a bremsstrahlung spectrum longwave X radiation for wood in the 0.02-0.2 g/cm/sup 2/ mass thickness range are given. A formular for calculating the attenuation factor of bremsstrahlung in wood is derived. On the basis of investigations into the behaviour of sensitivity functions of X-ray radiographic recommendations on choice of radiation energy are given. Experimental data on the sensitivity of pine tree samples in the density range investigated are given.

  11. Cross sections and modelling results for TGF- and positron spectrum produced by a negative stepped lightning leader

    NARCIS (Netherlands)

    C. Köhn (Christoph); U. Ebert (Ute)

    2012-01-01

    textabstractWe model the energy resolved angular distribution of TGFs and of positrons produced by a negative lightning leader stepping upwards in a thundercloud. First we present our new results for doubly differential cross sections for Bremsstrahlung and pair production based on the triply

  12. Scalar one-loop integrals

    NARCIS (Netherlands)

    Veltman, M.J.G.; Hooft, G. 't

    1979-01-01

    The completely general one-loop scalar one-, two-, three- and four-point functions are studied. Also an integral occurring in connection with soft bremsstrahlung is considered. Formulas in terms of Spence functions are given. An expansion for Spence functions with complex argument is presented.

  13. New beam monitoring tool for radiobiology experiments at the cyclotron ARRONAX.

    Science.gov (United States)

    Schwob, L; Koumeir, C; Servagent, N; Cherel, M; Guertin, A; Haddad, F; Métivier, V; Michel, N; Poirier, F; Rahmani, A; Varmenot, N

    2015-09-01

    The ARRONAX cyclotron is able to deliver alpha particles at 68 MeV. In the frame of radiological research, a new method is studied to infer in situ the deposited dose: it is based on the online measurement of the bremsstrahlung (>1 keV) produced by the interaction of the incident particle with the medium. Experiments are made using bombarded poly(methyl methacrylate) (PMMA)-equivalent water targets in order to characterise this continuous X-ray spectrum. The intensity of the bremsstrahlung spectrum allows for the beam monitoring. A simulation code of the bremsstrahlung has been built, and a good agreement is found with the experimental spectra. With this simulation, it is possible to predict the sensibility of this method: it varies with the target thickness, showing a good sensibility for thin target (<1000 µm) and saturation for thicker ones. Bremsstrahlung spectrum also shows a sensibility on the target's chemical composition. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. A new source of radiation in single-bubble sonoluminescence

    Indian Academy of Sciences (India)

    2017-03-28

    Mar 28, 2017 ... In this article, by considering single-bubble sonoluminescence and based on the hydrochemical model and thermal bremsstrahlung approach, for the first time two different origins of light have numerically been studied to describe the Ar bubble radiation in water at the moment of collapse: (a) radiation.

  15. A new source of radiation in single-bubble sonoluminescence

    Indian Academy of Sciences (India)

    In this article, by considering single-bubble sonoluminescence and based on the hydrochemical model and thermal bremsstrahlung approach, for the first time two different origins of light havenumerically been studied to describe the Ar bubble radiation in water at the moment of collapse: (a) radiation from the Ar gas inside ...

  16. X-ray fluorescence activities at Saha Institute of Nuclear Physics, India

    Indian Academy of Sciences (India)

    X-ray fluorescence (EDXRF) system was developed to analyse alloys by exposing them directly under the tube bremsstrahlung and also under monochromatic X-rays obtained from secondary targets. In both the cases, no standard sample is required. Using the above principle, some archaeological objects were analysed.

  17. A BaF2 crystal array for high energy-ray measurements

    Indian Academy of Sciences (India)

    Abstract. We shall discuss about the scientific motivation and construction of a 7 × 7 BaF2 crystal array at Variable Energy Cyclotron Centre, Calcutta. This detector would be used to measure high energy -ray photons from GDR decay and proton–neutron bremsstrahlung reactions at the present 88'' cyclotron and upcoming ...

  18. Hans Bethe, Quantum Mechanics, and the Lamb Shift

    Indian Academy of Sciences (India)

    cal effect. Another household word is the Bethe--Heitler formula for Bremsstrahlung whose agreement with data then available provided one of the earliest experimental supports for the .... to emit em radiation from a statianary state was zero! And the .... lution lies in demanding that the negative energy states be normally full ...

  19. Electromagnetic transition between molecular resonances in 8 Be

    Indian Academy of Sciences (India)

    This paper discusses the earlier indirect bremsstrahlung measurements and describes a recent experiment on the direct measurement of -transition between the 4+ and 2+ resonances. Experimental results are compared with various theories. The outlook on the measurement of 2+ → 0+ transition will be presented.

  20. X-ray generation by the interaction of laser pulses of GW and high repetition rate, with solid targets of Al, Cu, Cd and Au; Generacion de rayos X por interaccion de pulsos laser de GW y alta tasa de repeticion, con blancos solidos de Al, Cu, Cd, Au

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca Cuenca, C.; Rodriguez Entem, D.; Mendez Valverde, C.; Roso Franco, L.; Fernandez Gonzalez, F.

    2011-07-01

    In the present study we characterized the Bremsstrahlung radiation and X-ray emission associated with the radiation emitted during the interaction of laser pulses incident on solid targets of different material and discusses the radiation risk generated by the nature of this interaction.

  1. Feasibility study for the implementation of an intense linac-based neutron source facility in Sao Paulo

    CERN Document Server

    Arruda-Neto, J D T

    1999-01-01

    The implementation of an intense linac-based neutron source is proposed here, using the forthcoming 30 MeV electron CW-Microtron under construction in Sao Paulo. A method to estimate photoneutron fluxes, based on thin target bremsstrahlung approximation, has been developed. The versatility and possible broad range of applications associated with such a facility are addressed.

  2. Measurements of egg shell plasma parameters using laser-induced ...

    Indian Academy of Sciences (India)

    improved iterative Boltzmann plot method with six calcium atomic emission lines, and the electron number density of 6.1 × 1016 ... once-ionized calcium line at 393.37 nm. Based on the experimental ... beam from the plasma can be neglected and the inverse bremsstrahlung (IB) absorption was the dominant mechanism of ...

  3. Proof of the Feasibility of Coherent and Incoherent Schemes for Pumping a Gamma-Ray Laser

    Science.gov (United States)

    1989-06-01

    Fntered) 5CZ, R, fC ASS:Z A*ION C F TMIS PAGE(1+’h Dw a Enrer.d) 20. Abstract (continued) nature requiring the fusion of concepts taken from relatively...University of Texas at Dallas SPECTRAL CHARACTERIZATION OF INTENSE, SHORT DURATION BREMSSTRAHLUNG PULSES WITH NUCLER PHOTOACTIVATIO.N TECHNIQUES 8i by J. A

  4. Scattering and absorption differential cross sections for double ...

    Indian Academy of Sciences (India)

    dynamics implicitly, a mechanism of photon multiplication along with the bremsstrahlung in astrophysics, a major background process in the experimental study of another nonlin- ear QED process namely photon splitting in electric fields of heavy atoms and there is appreciable contribution of this process to total scattering ...

  5. Fundamental Quantum 1/F Noise in Ultrasmall Semiconductor Devices and Their Optimal Design Principles

    Science.gov (United States)

    1988-05-31

    emitted photons per unit frequency interval is obtained by dividing with the energy hf of one photon. The probability amplitude of photon emission [2q...of the squared probability amplitude of photon emission with the squared non - Bremsstrahlung amplitude which is independent of f. The ,U .n. *%~ Aw

  6. Practical gamma-ray spectrometry

    National Research Council Canada - National Science Library

    Gilmore, G.R

    2008-01-01

    ... of Photons 1.7.1 Annihilation radiation 1.7.2 Bremsstrahlung 1.7.3 Prompt gammas 1.7.4 X-rays 1.8 The Mathematics of Decay and Growth of Radioactivity 1.8.1 The decay equation 1.8.2 Growth of activity in reac...

  7. Determination of level widths in 15N using nuclear resonance fluorescence

    Directory of Open Access Journals (Sweden)

    Szücs T.

    2015-01-01

    Full Text Available Level widths in 15N have been measured with the nuclear resonance fluorescence (NRF technique. Solid nitrogen compounds, bremsstrahlung, and HPGe detectors have been used as target, beam, and detectors, respectively. The preliminarily level widths are in agreement with the literature values, but more precise.

  8. Photon Production Within Storage Capsules

    CERN Document Server

    Rittmann, P D

    2003-01-01

    This report provides tables and electronic worksheets that list the photon production rate within SrF2 and CsC1 storage capsules, particularly the continuous spectrum of bremsstrahlung photons from the slowing down of the emitted electrons (BREMCALC).

  9. FZR annual report 2003: Research for men and environment; FZR-Jahresbericht 2003: Forschung fuer Mensch und Umwelt

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-03-01

    The following topics are dealt with: A multi-purpose experimental facility for the model development of two-phase flows, the first nuclear-physics experiments with bremsstrahlung at the ELBE accelerator, the molecular mechanisms of vision and general principles of the cellular signal processing, colloids in environment, protein oxidation and sickness, nondestructive study on glass pretiosa using proton beams. (HSI)

  10. Quantum electrodynamics

    CERN Document Server

    Berestetskii, Vladimir B; Pitaevskii, L P

    1982-01-01

    Several significant additions have been made to the second edition, including the operator method of calculating the bremsstrahlung cross-section, the calcualtion of the probabilities of photon-induced pair production and photon decay in a magneticfield, the asymptotic form of the scattering amplitudes at high energies, inelastic scattering of electrons by hadrons, and the transformation of electron-positron pairs into hadrons.

  11. Beams 92: Proceedings. Volume 1: Invited papers, pulsed power

    Energy Technology Data Exchange (ETDEWEB)

    Mosher, D.; Cooperstein, G. [eds.] [Naval Research Lab., Washington, DC (United States)

    1993-12-31

    This report contains papers on the following topics: Ion beam papers; electron beam, bremsstrahlung, and diagnostics papers; radiating Z- pinch papers; microwave papers; electron laser papers; advanced accelerator papers; beam and pulsed power applications papers; pulsed power papers; and these papers have been indexed separately elsewhere.

  12. Electromagnetic dipole strength distribution in $^{124,128,132,134}$Xe below the neutron separation energy

    CERN Document Server

    Massarczyk, R; Dönau, F; Frauendorf, S; Bemmerer, D; Beyer, R; Butterling, M; Hannaske, R; Junghans, A; Koegler, T; Rusev, G; Schilling, K D; Schramm, G; Tonchev, A P; Tornow, W; Wagner, A

    2014-01-01

    Dipole strength functions in the chain of xenon isotopes are analyzed on the basis of photon-scatterde experiments with bremsstrahlung at the ELBE facility in Dresden, Germany, and at the HI S facility in Durham, North Carolina, USA. The evolution of dipole strength with neutron excess and nuclear deformation is studied.

  13. Plasma-statistical models of the atom in the theory of some collisional and radiative processes

    NARCIS (Netherlands)

    Astapenko, VA

    2002-01-01

    A plasma-statistical model was used to describe collisional and radiative processes involving target ionization, namely, collisional ionization of atoms and incoherent polarization bremsstrahlung. The cross sections of these processes were expressed through the Compton profile of X-ray scattering,

  14. Development of a new experimental setup for studying collisions of ...

    Indian Academy of Sciences (India)

    Development of a new electron-recoil ion/photon coincidence setup for investigating some of the electron induced collision processes, such as electron bremsstrahlung, electron backscattering, innershell excitation and multiple ionization of target atoms/molecules in bombardment of electrons having energies from 2.0 keV ...

  15. A radioactive ion beam facility using photofission

    CERN Document Server

    Diamond, W T

    1999-01-01

    Use of a high-power electron linac as the driver accelerator for a Radioactive Ion Beam (RIB) facility is proposed. An electron beam of 30 MeV and 100 kW can produce nearly 5x10 sup 1 sup 3 fissions/s from an optimized sup 2 sup 3 sup 5 U target and about 60% of this from a natural uranium target. An electron beam can be readily transmitted through a thin window at the exit of the accelerator vacuum system and transported a short distance through air to a water-cooled Bremsstrahlung-production target. The Bremsstrahlung radiation can, in turn, be transported through air to the isotope-production target. This separates the accelerator vacuum system, the Bremsstrahlung target and the isotope-production target, reducing remote handling problems. The electron beam can be scanned over a large target area to reduce the power density on both the Bremsstrahlung and isotope-production targets. These features address one of the most pressing technological challenges of a high-power RIB facility, namely the production o...

  16. Virtual-pion and two-photon production in pp scattering

    NARCIS (Netherlands)

    Scholten, O; Korchin, AY

    Two-photon production in pp scattering is proposed as a means of studying virtual-pion emission. Such a process is complementary to real-pion emission in pp scattering. The virtual-pion signal is embedded in a background of double-photon bremsstrahlung. We have developed a model to describe this

  17. Photon pair production in astrophysical transrelativistic plasmas

    Science.gov (United States)

    Stoeger, W. R.

    1977-01-01

    Photon pair-production processes in marginally relativistic (transrelativistic) accretion plasmas are investigated in both Planckian and non-Planckian cases. Pair production in a plasma with an equilibrium (Planck) spectrum is reviewed, and pair-concentration calculations are performed for three general non-Planckian situations most relevant to black-hole accretion scenarios: steady-state transrelativistic plasmas of relatively high density characterized by a pure bremsstrahlung spectrum, a comptonized bremsstrahlung spectrum, and an unsaturated Compton scattering spectrum. The results obtained indicate that for transrelativistic temperatures (600 million to 6 billion K) photon pair production is not generally a dominant process for a plasma with a pure bremsstrahlung spectrum, but becomes dominant for plasmas where comptonization is important. It is also shown that photon pair-creation processes in a transrelativistic bremsstrahlung-radiating plasma that is more than marginally optically thick to Compton scattering significantly alter the plasma's spectrum by forcing it to become black-body before it reaches relativistic temperatures. Pair production and instabilities in unsteady-state plasmas are briefly considered

  18. Simultaneous catalytic regime of tritium and helium-3 in D–D fusion ...

    Indian Academy of Sciences (India)

    A catalytic regime of tritium and helium-3 in deuterium–deuterium fusion, including ion–electron collisions, mechanical expansion, bremsstrahlung radiation, inverse Compton scattering losses and reacting particles energy effect has been investigated. In this paper a new fuel configuration, DT 3He, is formed by adding ...

  19. Target, purging magnet and electron collector design for scanned high-energy photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Roger; Aasell, Mats; Naefstadius, Peder; Brahme, Anders [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, PO Box 260, S-171 76 Stockholm (Sweden)

    1998-05-01

    A new method for producing very narrow and intense 50 MV bremsstrahlung beams with a half-width as low as 35 mm at a distance of 1 m from the target is presented. Such a beam is well suited for intensity modulation using scanned photon beams. An algorithm has been developed to minimize the width of the bremsstrahlung beam generated in a multilayer target by varying the individual layer thicknesses and atomic numbers under given constraints on the total target thickness and the mean energy of the transmitted electrons. Under such constraints the narrowest possible bremsstrahlung beam is obtained with a target composed of layers of monotonically increasing atomic number starting with the lowest possible value at the entrance side where the electrons impinge. It is also shown that the narrowest photon beam profile is associated with the highest possible forward photon yield. To be able to use the optimized target clinically it is desirable to be able to collect and stop all the electrons that are transmitted through the target. The electrons are most efficiently collected if they are kept close together, i.e. by minimizing the multiple scatter of the electrons and consequently the half-width of the generated bremsstrahlung beam. This is achieved by a thin low-atomic-number target. A dedicated electron stopper has been developed and integrated with the purging magnet. When the electron stopper is combined with a purging magnet, a primary photon collimator and a multileaf collimator, almost all of the transmitted electrons and their associated bremsstrahlung contamination can effectively be collected. The narrow photon beams from thin low-atomic-number targets have the additional advantage of producing the hardest and most penetrative photon spectrum possible, which is ideal for treating large deep-seated tumours. (author)

  20. A radioactive ion beam facility using photofission

    Science.gov (United States)

    Diamond, William T.

    1999-08-01

    Use of a high-power electron linac as the driver accelerator for a Radioactive Ion Beam (RIB) facility is proposed. An electron beam of 30 MeV and 100 kW can produce nearly 5×10 13 fissions/s from an optimized 235U target and about 60% of this from a natural uranium target. An electron beam can be readily transmitted through a thin window at the exit of the accelerator vacuum system and transported a short distance through air to a water-cooled Bremsstrahlung-production target. The Bremsstrahlung radiation can, in turn, be transported through air to the isotope-production target. This separates the accelerator vacuum system, the Bremsstrahlung target and the isotope-production target, reducing remote handling problems. The electron beam can be scanned over a large target area to reduce the power density on both the Bremsstrahlung and isotope-production targets. These features address one of the most pressing technological challenges of a high-power RIB facility, namely the production of high yields of neutron-rich ions with reasonable power density in the target. The cost of an electron linac of the required specifications, including the facility shielding, is significantly less than the cost of any other primary-beam accelerator that could produce a comparable fission yield. A high-power electron linac could also be used with a multifoil helium-jet target. A large number of thin uranium foils could be irradiated with the scanned Bremsstrahlung beam and the fission fragments captured in aerosol-loaded helium and transported to an ion source that is well removed from the intense radiation fields of the primary target. The fission yield would be less than 1% of that available from a thick target, but this approach might be the easiest technical solution to obtain useable yields with manageable radiation-safety problems.

  1. 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....

  2. X-ray analysis of nonMaxwellian distributions (current drive)

    Energy Technology Data Exchange (ETDEWEB)

    von Goeler, S.; Stevens, J.; Stodiek, W.

    1983-06-01

    The plasma bremsstrahlung emission is utilized to determine the shape of the electron velocity distribution in situations where it deviates strongly from a Maxwellian distribution. The instrumentation used to measure the hard x-ray emission is briefly discussed. Model calculations show that polarization measurements give best results for unrelativistic tails with tail temperatures T/sub b/ < 50 keV, whereas measurements of the angular distribution of the x-ray emission based on the forward scattering of bremsstrahlung for relativistic electrons yields the best information for T/sub b/ > 50 keV. The techniques were originally developed in order to analyze runaway discharges. Recently, they found new interest because of the formation of energetic electron tails during current drive. The first x-ray results from the current drive during LH heating on PLT are discussed.

  3. Determination of photon contamination dose of clinical electron beams using the generalized simulated annealing method; Determinação da dose dos fótons contaminantes de feixes de elétrons clínicos usando o Método de Recozimento Simulado Generalizado

    Energy Technology Data Exchange (ETDEWEB)

    Visbal, Jorge H. Wilches; Costa, Alessandro M. da, E-mail: jhwilchev@gmail.com [Universidade de Sao Paulo (USP), Ribeirão Preto, SP (Brazil). Faculdade de Filosofia, Ciências e Letras

    2017-07-01

    Clinical electron beams are composed of a mixture of pure electrons and Bremsstrahlung photons produced in the structures of the accelerator head as well as in the air. Accurate knowledge of these components is important for calculating the dose and for treatment planning. There are at least two approaches to deter-mine the contribution of the photons in the percentage depth dose of clinical electrons: a) Analytical Method that calculates the dose of the photons from the previous determination of the spectrum of the incident Bremsstrahlung photons; b) Adjustment method based on a semi-empirical biexponential formula where four parameters must be established from optimization methods. The results show that the generalized simulated annealing method can calculate the photon contamination dose by overestimating the dose in the tail no more than 0.6% of the maximum dose (electrons and photons). (author)

  4. Standard Guide for Absorbed-Dose Mapping in Radiation Processing Facilities

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This document provides guidance in determining absorbed-dose distributions in products, materials or substances irradiated in gamma, X-ray (bremsstrahlung) and electron beam facilities. Note 1—For irradiation of food and the radiation sterilization of health care products, other specific ISO and ISO/ASTM standards containing dose mapping requirements exist. For food irradiation, see ISO/ASTM 51204, Practice for Dosimetry in Gamma Irradiation Facilities for Food Processing and ISO/ASTM 51431, Practice for Dosimetry in Electron and Bremsstrahlung Irradiation Facilities for Food Processing. For the radiation sterilization of health care products, see ISO 11137: 1995, Sterilization of Health Care Products Requirements for Validation and Routine Control Radiation Sterilization. In those areas covered by ISO 11137, that standard takes precedence. ISO/ASTM Practice 51608, ISO/ASTM Practice 51649, and ISO/ASTM Practice 51702 also contain dose mapping requirements. 1.2 Methods of analyzing the dose map data ar...

  5. Computer simulation of electron-positron pair production by channeling radiation in amorphous converter

    Science.gov (United States)

    Abdrashitov, S. V.; Bogdanov, O. V.; Dabagov, S. B.; Pivovarov, Yu L.; Tukhfatullin, T. A.

    2016-07-01

    We consider the radiator-converter approach at 200 MeV channeled electrons (the SPARC_LAB LNF facility energies) for the case of using W crystalline radiator and W amorphous converter. A comparison of the positron production by the axial channeling radiation and the bremsstrahlung is performed. The positron stopping in the convertor is studied by means of computer simulations. It is shown that for the maximum yield of positrons the thickness of the W amorphous converter should be taken 0.35 cm in the case of using the axial channeling radiation resulting to total yield of positrons 5 10-3 e+/e- and 0.71 cm in the case of using the bremsstrahlung resulting to total yield of positrons 3.3 10-3 e+/e-.

  6. Simulation of intense laser-dense matter interactions. X-ray production and laser absorption

    Energy Technology Data Exchange (ETDEWEB)

    Ueshima, Yutaka; Kishimoto, Yasuaki; Sasaki, Akira [Japan Atomic Energy Research Inst., Neyagawa, Osaka (Japan). Kansai Research Establishment; Sentoku, Yasuhiko; Tajima, Toshiki

    1998-03-01

    The development of short-pulse ultra high intensity lasers will enable us to generate short-pulse intense soft and hard X-rays. Acceleration of an electron in laser field generates intense illuminated located radiation, Larmor radiation, around KeV at 10{sup 18} W/cm{sup 2} with 100 TW and 1 {mu}m wave length laser. The Coulomb interaction between rest ions and relativistic electron generates broad energy radiation, bremsstrahlung emission, over MeV at 10{sup 18} W/cm{sup 2} with the same condition. These intense radiations come in short pulses of the same order as that of the irradiated laser. The generated intense X-rays, Larmor and bremsstrahlung radiation, can be applied to sources of short pulse X-ray, excitation source of inner-shell X-ray laser, position production and nuclear excitation, etc. (author)

  7. Microtron MT 25 as a source of neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Kralik, M.; Solc, J. [Czech Metrology Institute, CZ-102 00 Prague 10 (Czech Republic); Chvatil, D.; Krist, P.; Turek, K. [Nuclear Physics Institute, p.r.i., AS CR, CZ-250 68 Rez (Czech Republic); Granja, C. [Institute of Experimental and Applied Physics, Horska 3a/22, CZ-128 00 Prague 2 (Czech Republic)

    2012-08-15

    The objective was to describe Microtron MT25 as a source of neutrons generated by bremsstrahlung induced photonuclear reactions in U and Pb targets. Bremsstrahlung photons were produced by electrons accelerated at energy 21.6 MeV. Spectral fluence of the generated neutrons was calculated with MCNPX code and then experimentally determined at two positions by means of a Bonner spheres spectrometer in which the detector of thermal neutrons was replaced by activation Mn tablets or track detectors CR-39 with a {sup 10}B radiator. The measured neutron spectral fluence and the calculated anisotropy served for the estimation of neutron yield from the targets and for the determination of ambient dose equivalent rate at the place of measurement. Microtron MT25 is intended as one of the sources for testing neutron sensitive devices which will be sent into the space.

  8. First e⁻/γ Commissioning Results for the GlueX Experiment/Hall D at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    McCaughan, Michael D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Satogata, Todd J. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Roblin, Yves R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Benesch, Jay F. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    Experimental Hall D, with flagship experiment GlueX, was constructed as part of the 12 GeV CEBAF upgrade. A new magnetically extracted electron beam line was installed to support this hall. Bremsstrahlung photons from retractable radiators are delivered to the experiment through a series of collimators following a long drift to allow for beam convergence. Coherent Bremsstrahlung generated by interaction with a diamond radiator will achieve a nominal 40% linear polarization and photon energies between 8.5 and 9 GeV from 12.1 GeV electrons, which are then tagged or diverted to a medium power 60kW electron dump. The expected photon flux is 107-108 Hz. This paper discusses the experimental line design, commissioning experience gained since first beam in spring 2014, and the present results of beam commissioning by the experiment.

  9. Advances in Monte-Carlo code TRIPOLI-4®'s treatment of the electromagnetic cascade

    Science.gov (United States)

    Mancusi, Davide; Bonin, Alice; Hugot, François-Xavier; Malouch, Fadhel

    2018-01-01

    TRIPOLI-4® is a Monte-Carlo particle-transport code developed at CEA-Saclay (France) that is employed in the domains of nuclear-reactor physics, criticality-safety, shielding/radiation protection and nuclear instrumentation. The goal of this paper is to report on current developments, validation and verification made in TRIPOLI-4 in the electron/positron/photon sector. The new capabilities and improvements concern refinements to the electron transport algorithm, the introduction of a charge-deposition score, the new thick-target bremsstrahlung option, the upgrade of the bremsstrahlung model and the improvement of electron angular straggling at low energy. The importance of each of the developments above is illustrated by comparisons with calculations performed with other codes and with experimental data.

  10. Reconstruction of Electrons with the Gaussian-Sum Filter in the CMS traker at LHC

    CERN Document Server

    Adam, W; Strandlie, A; Todorov, T

    2003-01-01

    The bremsstrahlung energy loss distribution of electrons propagating in matter is highly non Gaussian. Because the Kalman filter relies solely on Gaussian probability density functions, it might not be an optimal reconstruction algorithm for electron tracks. A Gaussian-sum filter (GSF) algorithm for electron track reconstruction in the CMS tracker has therefore been developed. The basic idea is to model the bremsstrahlung energy loss distribution by a Gaussian mixture rather than a single Gaussian. It is shown that the GSF is able to improve the momentum resolution of electrons compared to the standard Kalman filter. The momentum resolution and the quality of the estimated error are studied with various types of mixture models of the energy loss distribution.

  11. A novel “sandwich” method for observation of the keyhole in deep penetration laser welding

    Science.gov (United States)

    Zhang, Yi; Chen, Genyu; Wei, Haiying; Zhang, Jun

    2008-02-01

    A sandwich method was used to observe the keyhole in deep penetration laser welding, which provided an effective way to analyze both the Fresnel and inverse Bremsstrahlung absorption. In the transparent metal-analog system, different densities of metal vapor, ionized atoms, and free electrons in the keyhole can be simulated by changing the thickness of aluminum films. The research results show that inverse Bremsstrahlung absorption exerts a tremendous influence on the energy absorption of the laser beam for CO 2 laser welding. Low density of keyhole plasma benefits the incident laser energy coupling to the materials. However, excess density of keyhole plasma baffles the transmission of the incident laser beam to the interior material. By comparing inflow energy and outflow energy, there exits an energy balance on the keyhole wall by balancing the absorbed laser intensity and heat flux on the wall.

  12. Ray-based calculations of laser backscatter in ICF targets

    CERN Document Server

    Strozzi, D J; Hinkel, D E; Froula, D H; London, R A; Callahan, D A

    2008-01-01

    A steady-state model for Brillouin and Raman backscatter along a laser ray path is presented. The daughter plasma waves are treated in the strong damping limit, and have amplitudes given by the (linear) kinetic response to the ponderomotive drive. Pump depletion, inverse-bremsstrahlung damping, bremsstrahlung emission, Thomson scattering off density fluctuations, and whole-beam focusing are included. The numerical code Deplete, which implements this model, is described. The model is compared with traditional linear gain calculations, as well as ``plane-wave'' simulations with the paraxial propagation code pF3D. Comparisons with Brillouin-scattering experiments at the Omega Laser Facility show that laser speckles greatly enhance the reflectivity over the Deplete results. An approximate upper bound on this enhancement is given by doubling the Deplete coupling coefficient. Analysis with Deplete of an ignition design for the National Ignition Facility (NIF), with a peak radiation temperature of 285 eV, shows enco...

  13. Reconstruction of Electron Tracks With the Gaussian-Sum Filter

    CERN Document Server

    Adam, W; Strandlie, A; Todorov, T

    2003-01-01

    Due to the highly non-Gaussian shape of the bremsstrahlung energy loss distribution the standard Kalman filter is not the optimal algorithm for the reconstruction of electron tracks, since it implicitely assumes that all noise probability density functions involved are Gaussian. A Gaussian-sum filter (GSF) algorithm for electron track reconstruction in the CMS Tracker at LHC has therefore been developed. The basic idea is to model the bremsstrahlung distribution by a Gaussian mixture rather than a single Gaussian. It is shown that the GSF is able to improve the momentum resolution of electrons compared to the standard Kalman filter. The impact of the number of components in the mixture on the quality and the precision of the estimates is studied.

  14. Reconstruction of Electrons with the Gaussian-Sum Filter in the CMS Tracker at the LHC

    CERN Document Server

    Adam, Wolfgang; Strandlie, Are; Todor, T

    2005-01-01

    The bremsstrahlung energy loss distribution of electrons propagating in matter is highly non-Gaussian. Because the Kalman filter relies solely on Gaussian probability density functions, it is not necessarily the optimal reconstruction algorithm for electron tracks. A Gaussian-sum filter (GSF) algorithm for electron reconstruction in the CMS tracker has therefore been developed and implemented. The basic idea is to model the bremsstrahlung energy loss distribution by a Gaussian mixture rather than by a single Gaussian. It is shown that the GSF is able to improve the momentum resolution of electrons compared to the standard Kalman filter. The momentum resolution and the quality of he error estimate are studied both with a fast simulation, modelling the radiative energy loss in a simplified detector, and the full CMS tracker simulation.

  15. Reconstruction of electrons with the Gaussian-Sum filter in the ATLAS inner detector

    CERN Document Server

    Atkinson, T

    2006-01-01

    The ATLAS detector's ability to reconstruct and identify electrons with high precision is critical both for the calibration of the detector and for the analysis of many physics processes. High energy electrons traversing matter loose energy predominantly by bremsstrahlung. A well known model for bremsstrahlung is the Bethe- Heitler distribution, which is highly non-Gaussian. Linear fitters, such as the Kaiman filter (KF), model energy losses as Gaussian distributions and thus are not optimal for the reconstruction of electrons. The Gaussian-Sum filter (GSF) is a non-linear generalisation of the KF. This algorithm has been implemented for the reconstruction of electrons within ATLAS. The GSF models the Bethe- Heitler distribution by a weighted sum of Gaussian distributions. A comparison between the reconstruction performance of the GSF and the KF is presented using simulated events generated using the geometry of the 2004 ATLAS test-beam.

  16. Sensitivity of Inferred Electron Temperature from X-ray Emission of NIF Cryogenic DT Implosions

    Energy Technology Data Exchange (ETDEWEB)

    Klem, Michael [Univ. of Dallas, Irving, TX (United States)

    2015-05-01

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory seeks to achieve thermonuclear ignition through inertial confinement fusion. The accurate assessment of the performance of each implosion experiment is a crucial step. Here we report on work to derive a reliable electron temperature for the cryogenic deuteriumtritium implosions completed on the NIF using the xray signal from the Ross filter diagnostic. These Xrays are dominated by bremsstrahlung emission. By fitting the xray signal measured through each of the individual Ross filters, the source bremsstrahlung spectrum can be inferred, and an electron temperature of the implosion hot spot inferred. Currently, each filter is weighted equally in this analysis. We present work quantifying the errors with such a technique and the results from investigating the contribution of each filter to the overall accuracy of the temperature inference. Using this research, we also compare the inferred electron temperature against other measured implosion quantities to develop a more complete understanding of the hotspot physics.

  17. Photon and photoneutron spectra produced in radiotherapy Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Martinez O, S. A. [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte Km. 1, Via Paipa Tunja, Boyaca (Colombia); Benites R, J. L. [Universidad Autonoma de Nayarit, Postgrado CBAP, Carretera Tepic Compostela Km. 9, Xalisco, Nayarit (Mexico); Lallena, A. M., E-mail: fermineutron@yahoo.com [Universida de Granada, Departamento de Fisica Atomica, Molecular y Nuclear, E-18071 Granada (Spain)

    2011-10-15

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10{sup -6} and 1 MeV. Neutron and Bremsstrahlung spectra show the same features regardless of the linac voltage. The amount of photons and neutrons produced by the 15 MV linac is smaller than that found for the 18 MV linac. As expected, Bremsstrahlung spectra ends according to the voltage used to accelerate the electrons. (Author)

  18. 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.

  19. Explosive Emission and Gap Closure from a Relativistic Electron Beam Diode

    Science.gov (United States)

    2013-06-01

    perforated anode for high power microwave (HPM) production or flash X-ray radiography . In accelerator applications, the electrons from cold cathodes are...Bremsstrahlung radiation [3-8]. It is imperative to study the beam physics even in the accelerators used for radiography in order to optimize the...then slowing to 10 cm/ µs. Explosive emission cold cathodes are also employed in virtual cathode oscillators for HPM production [11]. The RITS-6

  20. Imaging of high-energy x-ray emission from cryogenic thermonuclear fuel implosions on the NIF.

    Science.gov (United States)

    Ma, T; Izumi, N; Tommasini, R; Bradley, D K; Bell, P; Cerjan, C J; Dixit, S; Döppner, T; Jones, O; Kline, J L; Kyrala, G; Landen, O L; LePape, S; Mackinnon, A J; Park, H-S; Patel, P K; Prasad, R R; Ralph, J; Regan, S P; Smalyuk, V A; Springer, P T; Suter, L; Town, R P J; Weber, S V; Glenzer, S H

    2012-10-01

    Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide broadband time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered implosions. This diagnostic measures the temperature- and density-sensitive bremsstrahlung emission and provides estimates of hot spot mass, mix mass, and pressure.

  1. Hard x-ray (>100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the NIF.

    Science.gov (United States)

    Döppner, T; Dewald, E L; Divol, L; Thomas, C A; Burns, S; Celliers, P M; Izumi, N; Kline, J L; LaCaille, G; McNaney, J M; Prasad, R R; Robey, H F; Glenzer, S H; Landen, O L

    2012-10-01

    We have fielded a hard x-ray (>100 keV) imager with high aspect ratio pinholes to measure the spatially resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions and are a source of preheat to the deuterium-tritium fuel. First measurements show that hot electron preheat does not limit obtaining the fuel areal densities required for ignition and burn.

  2. The AMY experiment: Microwave emission from air shower plasmas

    Directory of Open Access Journals (Sweden)

    Alvarez-Muñiz J.

    2016-01-01

    Full Text Available You The Air Microwave Yield (AMY experiment investigate the molecular bremsstrahlung radiation emitted in the GHz frequency range from an electron beam induced air-shower. The measurements have been performed at the Beam Test Facility (BTF of Frascati INFN National Laboratories with a 510 MeV electron beam in a wide frequency range between 1 and 20 GHz. We present the apparatus and the results of the tests performed.

  3. Electron bremstrahlung recovery in ATLAS tracking using Dynamic Noise Adjustment

    CERN Document Server

    Kartvelishvili, V

    2007-01-01

    A number of approaches are being used in ATLAS reconstruction software, aiming to improve electron momentum measurement by taking into account the effects due to bremsstrahlung at various stages. One of them, designed and implemented in ATLAS, is covered in this talk. The method applies Dynamic Noise Adjustment (DNA) during the track fitting process based on the Kalman filter, and is both fast and efficient

  4. A Hybrid Model for Multiscale Laser Plasma Simulations with Detailed Collisional Physics

    Science.gov (United States)

    2017-06-23

    the effects of inelastic collisions on the Multi-Fluid description of plasmas. 15. SUBJECT TERMS Electric propulsion; plasma; collisional...inverse Bremsstrahlung. One key physical process not in- cluded is radiation transfer; instead an optical escape factor is used to model the loss of...the Monte Carlo integration had excellent agreement with the full transfer integral[6]. A key finding during this investigation was the effect that the

  5. Selected topics on e/sup +/e/sup -/ physics

    CERN Document Server

    Wolf, G

    1980-01-01

    The author does not attempt to cover the whole field of e/sup +/e/sup -/ physics, rather, a few topics are discussed which are at present of particular interest. These are: the behaviour of form factors, the characteristics of the tau lepton, the charmonium spectroscopy, charmed mesons and baryons, the T, T' family and data obtained at the new DESY storage ring PETRA on jet formation and gluon bremsstrahlung. (180 refs).

  6. Superluminal Dark Neutrinos

    OpenAIRE

    Aref'eva, Irina Ya.; Volovich, Igor V.

    2011-01-01

    The OPERA collaboration has claimed the discovery of supeluminal neutrino propagation. However the superluminal interpretation of the OPERA result was refuted by Cohen and Glashow because it was shown that such superluminal neutrinos would lose energy rapidly via the bremsstrahlung of electron-positron pairs (arXiv:1109.6562). We note that the superluminal interpretation is still possible if there exists a new (dark) neutrino which can propagate with a superluminal velocity and which couples ...

  7. Page 1 100 R K Rout and A Shyam (or lost) if hot spot expands ...

    Indian Academy of Sciences (India)

    flow per unit area in longitudinal and radial direction, Bºy and 3rd are free-free and free-bound bremsstrahlung coefficients. nn, T, and In are hot spot density, temperature. (ion and electron temperatures are assumed to be equal) and current. qen = -2.5 k T. Jºſe (6) qar = % ha Th/dr (7). & = 3nak T. (8). Jah = 0, E-, + (pºd Tiſdz ...

  8. Suprathermal electrons in a vacuum spark discharge

    Energy Technology Data Exchange (ETDEWEB)

    Bashutin, O. A., E-mail: boa308@mail.ru; Savjolov, A. S., E-mail: savjolov@plasma.mephi.ru [National Research Nuclear University MEPhI (Russian Federation)

    2016-04-15

    Results of experiments on the detection of suprathermal electron beams in the plasma of a highcurrent low-inductance vacuum spark by means of space-resolved spectral X-ray polarimetry are presented. It is shown that the observed polarization of bremsstrahlung may be caused by an ~100-keV electron beam propagating along the discharge axis from the pinching region toward the anode. The influence of the discharge initiation conditions on the parameters of the generated electron beams is analyzed.

  9. Recent developments on high-energy gravitational scattering

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    After a quick reminder of earlier results I will discuss some recent progress in the high-energy gravitational scattering of particles, strings, and branes and, in particular: 1. Gravitational bremsstrahlung; 2. Causality constraints in the presence of higher derivative corrections; 3. Absorption of an energetic closed string by a stack of D-branes. These developments should eventually help us understand how information is preserved in the quantum analog of classical gravitational collapse.

  10. Energy Flow in Dense Off-Equilibrium Plasma

    Science.gov (United States)

    2016-07-15

    is the collision time. In this limit the motion is reversible and no energy is absorbed by the plasma. A theory which explains the conversion of...bremsstrahlung where an electron absorbs light during a “ collision ” with an ion [14]. The collisionality in SCP is greatly affected by collective screening...LOS ANGELES, CA 90095-0001 07/15/2016 Final Report DISTRIBUTION A: Distribution approved for public release. Air Force Research Laboratory AF Office

  11. ELECTRONIC-STRUCTURE OF COO, LI-DOPED COO, AND LICOO2

    NARCIS (Netherlands)

    VANELP, J; WIELAND, JL; ESKES, H; KUIPER, P; SAWATZKY, GA; DEGROOT, FMF; TURNER, TS

    1991-01-01

    The electronic structure of Li(x)Co(1-x)O (0.01 less-than-or-equal-to x less-than-or-equal-to 0.2), LiCoO2, and Co3O4(1% Li) has been investigated using x-ray photoemission spectroscopy (XPS), bremsstrahlung isochromat spectroscopy (BIS), and x-ray-absorption spectroscopy. The experimental results

  12. Pion Polarizability Status Report (2017)

    OpenAIRE

    Moinester, Murray

    2017-01-01

    The electric ${\\alpha}_{\\pi}$ and magnetic $\\beta_{\\pi}$ charged pion Compton polarizabilities are of fundamental interest in the low-energy sector of quantum chromodynamics (QCD).They are directly linked to the phenomenon of spontaneously broken chiral symmetry within QCD and to the dynamics of the pion-photon interaction.The combination (${\\alpha}_{\\pi}-\\beta_{\\pi}$) was measured by:(1) CERN COMPASS via radiative pion Primakoff scattering (Bremsstrahlung) in the nuclear Coulomb field, ${\\pi...

  13. Characterizing Three Candidate Magnetic Cataclysmic Variables From SDSS: XMM-Newton and Optical Follow-Up Observations

    Science.gov (United States)

    2006-08-29

    files ready for spectral analysis in XSPEC , lcmath created background-subtracted light curves and combined the twoMOS light curves, while earth2sun...through the Galaxy. Typically, we used a single bremsstrahlung model or a model in- cluding explicit line emission (the XSPEC model MEKAL) as expected...well; hence, no error estimates are available. b We used the XSPEC model CEMEKL, in which a fine grid of MEKAL models are co-added, with the emission

  14. Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01

    CERN Document Server

    Aguilar, M; Allaby, James V; Alpat, B; Ambrosi, G; Anderhub, H; Ao, L; Arefev, A; Azzarello, P; Baldini, L; Basile, M; Barancourt, D; Barão, F; Barbier, G; Barreira, G; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Blasko, S; Bölla, G; Boschini, M; Bourquin, M; Brocco, L; Bruni, G; Buénerd, M; Burger, J D; Burger, W J; Cai, X D; Camps, C; Cannarsa, P; Capell, M; Cardano, F; Casadei, D; Casaus, J; Castellini, G; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Tzi Hong Chiueh; Cho, K; Choi, M J; Choi, Y Y; Cindolo, F; Commichau, V; Contin, A; Cortina, E; Cristinziani, M; Dai, T S; Delgado, C; Difalco, S; Djambazov, L; D'Antone, I; Dong, Z R; Emonet, P; Engelberg, J; Eppling, F J; Eronen, T; Esposito, G; Extermann, P; Favier, Jean; Fiandrini, E; Fisher, P H; Flügge, G; Fouque, N; Galaktionov, Yu; Gast, H; Gervasi, M; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Hungerford, W; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kim, D H; Kim, G N; Kim, K S; Kim, M Y; Klimentov, A; Kossakowski, R; Kounine, A; Koutsenko, V F; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Lanciotti, E; Laurenti, G; Lebedev, A; Lechanoine-Leluc, C; Lee, M W; Lee, S C; Levi, G; Liu, C L; Liu, H T; Lu, G; Lü, Y S; Lübelsmeyer, K; Luckey, D; Lustermann, W; Maña, C; Margotti, A; Mayet, F; McNeil, R R; Meillon, B; Menichelli, M; Mihul, A; Mujunen, A; Oliva, A; Olzem, J; Palmonari, F; Park, H B; Park, W H; Pauluzzi, M; Pauss, F; Perrin, E; Pesci, A; Pevsner, A; Pilo, F; Pimenta, M; Plyaskin, V; Pozhidaev, V; Pohl, M; Produit, N; Rancoita, P G; Rapin, D; Raupach, F; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Ro, S; Röser, U; Rossin, C; Sagdeev, R; Santos, D; Sartorelli, G; Sbarra, C; Schael, S; Schultzvon Dratzig, A; Schwering, G; Seo, E S; Shin, J W; Shoumilov, E; Shoutko, V; Siedenburg, T; Siedling, R; Son, D; Song, T; Spinella, F; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tornikoski, M; Torsti, J; Trumper, J; Ulbricht, J; Urpo, S; Valtonen, E; Vandenhirtz, J; Velikhov, E P; Verlaat, B; Vetlitskii, I; Vezzu, F; Vialle, J P; Viertel, G; Vite, D; Von Gunten, H; Waldmeier-Wicki, S; Wallraff, W; Wang, B C; Wang, J Z; Wiik, K; Williams, C; Wu, S X; Xia, P C; Xu, S; Yan, J L; Yan, L G; Yang, C G; Yang, J; Yang, M; Ye, S W; Xu, Z Z; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhou, Y; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B; Zuccon, P

    2007-01-01

    A measurement of the cosmic ray positron fraction e+/(e+ + e-) in the energy range of 1-30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 10^6 is reached by identifying converted bremsstrahlung photons emitted from positrons.

  15. Next-to-leading order correction to the factorization limit of the radiation spectrum

    Science.gov (United States)

    Bondarenco, M. V.

    2017-10-01

    A next-to-leading order correction to the high-energy factorization limit of radiation spectrum from an ultra-relativistic electron scattering in an external field is evaluated. Generally, it does not express through scattering characteristics, and accounts for smoothness of the crossover between the initial and final electron asymptotes. A few examples of application of this formula are given, including bremsstrahlung in amorphous matter and undulator radiation.

  16. A model for electric field enhancement in lightning leader tips to levels allowing X-ray and γ ray emissions

    DEFF Research Database (Denmark)

    Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

    2015-01-01

    that the ionization channels of streamers limit the lateral expansion of the ionization wave, thereby enhancing the peak electric field to values allowing an acceleration of low-energy electrons into the runaway regime where electrons efficiently generate bremsstrahlung. The results suggest that the inhomogeneous...... ionization environment at the new leader tip amplifies the production rate of energetic electrons relative to a homogeneous environment considered in the past studies....

  17. Investigation of the vapour-plasma plume in the welding of titanium by high-power ytterbium fibre laser radiation

    Science.gov (United States)

    Bykovskiy, D. P.; Petrovskii, V. N.; Uspenskiy, S. A.

    2015-03-01

    The vapour-plasma plume produced in the welding of 6-mm thick VT-23 titanium alloy plates by ytterbium fibre laser radiation of up to 10 kW power is studied in the protective Ar gas medium. High-speed video filming of the vapour-plasma plume is used to visualise the processes occurring during laser welding. The coefficient of inverse bremsstrahlung by the welding plasma plume is calculated from the data of the spectrometric study.

  18. Prospects for Photon-Photon and Photon-Proton Measurements with Forward Proton Taggers in ATLAS

    CERN Document Server

    Trzebinski, Maciej; The ATLAS collaboration

    2017-01-01

    geometric acceptance. The main results of the total, elastic and inelastic cross sections measurements performed with the ATLAS/ALFA detectors are presented. Possibility of diffractive bremsstrahlung and exclusive pion-pair photoproduction studies with the data from ATLAS/ALFA are discussed. Finally, the advantage of using a proton tagging technique for a high-statistics data recorded by the AFP detectors in the precision measurements of anomalous gauge couplings and invisible objects is discussed.

  19. Gravitational luminosity of a hot plasma in R{sup 2} gravity

    Energy Technology Data Exchange (ETDEWEB)

    Nadiri Niri, B.; Jahan, A.; Corda, C. [Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of)

    2016-12-15

    The R{sup 2}-gravity contribution to the energy loss of a hot plasma due to gravitational bremsstrahlung is calculated in the linearized theory on the basis of classical Coulomb scattering of plasma constituents in small-angle scattering approximation. The explicit dependence of the gravitational luminosity on the plasma temperature is derived and its relevance to the Einstein gravity is demonstrated. The result, when applied to the Sun as a hot plasma, shows very good agreement with available data. (orig.)

  20. Measurement of Direct Photon Emission in K+-->π+π0γ Decay

    Science.gov (United States)

    Adler, S.; Aoki, M.; Ardebili, M.; Atiya, M. S.; Bergbusch, P. C.; Blackmore, E. W.; Bryman, D. A.; Chiang, I.-H.; Convery, M. R.; Diwan, M. V.; Frank, J. S.; Haggerty, J. S.; Inagaki, T.; Ito, M. M.; Kabe, S.; Kettell, S. H.; Kishi, Y.; Kitching, P.; Kobayashi, M.; Komatsubara, T. K.; Konaka, A.; Kuno, Y.; Kuriki, M.; Kycia, T. F.; Li, K. K.; Littenberg, L. S.; MacDonald, J. A.; McPherson, R. A.; Meyers, P. D.; Mildenberger, J.; Muramatsu, N.; Nakano, T.; Numao, T.; Poutissou, J.-M.; Poutissou, R.; Redlinger, G.; Sato, T.; Shinkawa, T.; Shoemaker, F. C.; Soluk, R.; Stone, J. R.; Strand, R. C.; Sugimoto, S.; Witzig, C.; Yoshimura, Y.

    2000-12-01

    We have performed a measurement of the K+-->π+π0γ decay and have observed 2×104 events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of \\(4.7+/-0.8+/-0.3\\)×10-6 in the π+ kinetic energy region of 55 to 90 MeV and requires no component due to interference with inner bremsstrahlung.

  1. Measurement of Direct Photon Emission in K{sup +}{yields}{pi}{sup +}{pi}

    Energy Technology Data Exchange (ETDEWEB)

    Adler, S.; Aoki, M.; Ardebili, M.; Atiya, M. S.; Bergbusch, P. C.; Blackmore, E. W.; Bryman, D. A.; Chiang, I.-H.; Convery, M. R.; Diwan, M. V. (and others)

    2000-12-04

    We have performed a measurement of the K{sup +}{yields}{pi}{sup +}{pi}{sup 0}{gamma} decay and have observed 2x10{sup 4} events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7{+-}0.8{+-}0.3)x10{sup -6} in the {pi}{sup +} kinetic energy region of 55 to 90MeV and requires no component due to interference with inner bremsstrahlung.

  2. Measurement of direct photon emission in K+-->pi(+)pi(0)gamma decay

    Science.gov (United States)

    Adler; Aoki; Ardebili; Atiya; Bergbusch; Blackmore; Bryman; Chiang; Convery; Diwan; Frank; Haggerty; Inagaki; Ito; Kabe; Kettell; Kishi; Kitching; Kobayashi; Komatsubara; Konaka; Kuno; Kuriki; Kycia; Li; Littenberg

    2000-12-04

    We have performed a measurement of the K+-->pi(+)pi(0)gamma decay and have observed 2x10(4) events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7+/-0.8+/-0. 3)x10(-6) in the pi(+) kinetic energy region of 55 to 90 MeV and requires no component due to interference with inner bremsstrahlung.

  3. New Results on Precision Studies of Heavy Vector Boson Physics

    CERN Document Server

    Ward, B F L; Jadach, Stanislaw; Placzek, Wiesiek; Skrzypek, M; Was, Z; Yost, S A

    2004-01-01

    We present new results for two important heavy vector boson physics processes: (1), virtual corrections to hard bremsstrahlung which are relevant to precision predictions for the radiative return process in Z boson production at and beyond LEP2 energies ; and, (2), electric charge screening effects in single W production with finite p_T, multiple photon radiation in high energy collider physics processes. In both cases we show that we improve the respective precision tag significantly. Phenomenological implications are discussed.

  4. The spectrometer/telescope for imaging X-rays on board the ESA Solar Orbiter spacecraft

    Energy Technology Data Exchange (ETDEWEB)

    Krucker, S. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Space Sciences Laboratory, UC Berkeley (United States); Benz, A.O. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Hurford, G.J. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Space Sciences Laboratory, UC Berkeley (United States); Arnold, N.G. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Orleański, P. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Space Research Center of Polish Academy of Sciences (Poland); Gröbelbauer, H.-P.; Casadei, D.; Kobler, S.; Iseli, L.; Wiehl, H.J.; Csillaghy, A.; Etesi, L.; Hochmuth, N.; Battaglia, M. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Bednarzik, M.; Resanovic, R. [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, Villigen (Switzerland); Grimm, O., E-mail: oliver.grimm@phys.ethz.ch [ETH Zürich (Switzerland); Viertel, G.; Commichau, V.; Howard, A. [ETH Zürich (Switzerland); and others

    2013-12-21

    Solar Orbiter is a Sun-observing mission led by the European Space Agency, addressing the interaction between the Sun and the heliosphere. It will carry ten instruments, among them the X-ray imaging spectrometer STIX. STIX will determine the intensity, spectrum, timing, and location of thermal and accelerated electrons near the Sun through their bremsstrahlung X-ray emission. This report gives a brief overview of the STIX scientific goals and covers in more detail the instrument design and challenges.

  5. Polarization Observables T and F in single π0- and η-Photoproduction off quasi-free Nucleons

    Directory of Open Access Journals (Sweden)

    Strub Thomas

    2014-01-01

    Single π0- and η-photoproduction off a transversally polarized d-butanol target has been measured with circularly polarized bremsstrahlung photons generated by the MAMI-C electron microtron. With the nearly 4π acceptance of the combined Crystal Ball/TAPS setup the double polarization observable F and the target asymmetry T can be extracted for the first time for polarized, quasi-free neutrons over a wide energy and angular range.

  6. Radiation by energetic electrons accelerated by wave-particle interaction: a plausible mechanism for X-ray emission from the Venus mantle

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, R. [STFC Rutherford Appleton Lab., Didcot, Oxon (United Kingdom). Space Science and Technology Dept.; Strathclyde Univ., Glasgow (United Kingdom). Physics Dept.; Quest, K.B. [California Univ., San Diego, La Jolla, CA (United States). ECE Dept.; Shapiro, V.D. [California Univ., San Diego, La Jolla, CA (United States). Physics Dept.; Kellett, B.J. [STFC Rutherford Appleton Lab., Didcot, Oxon (United Kingdom). Space Science and Technology Dept.

    2008-07-01

    In this paper it is argued that recently observed X-ray emission from non-magnetic planets (Dennerl et al., 2002) can be explained as a combination of bremsstrahlung and line K-shell radiation produced by the interaction of energetic electrons with the neutral atmosphere. Numerical simulations show that the modified two stream instability can generate energetic 100 eV electrons that are observed and these electrons can produce X-ray emission. (orig.)

  7. Kinetic model of GMSW in an anisotropic plasma

    CERN Document Server

    Ignatyev, Yu G

    2011-01-01

    A kinetic model of gravimagnetic shock waves (GMSW) in a locally anisotropic plasma is investigated. The equations of a drift approximation are written, and the moments of the distribution function are calculated. Solutions of the drift equations for a highly anisotropic ultrarelativistic plasma are found. It is shown that in this case the GMSW essentially affect the angular characteristics and the intensity of the magneto - bremsstrahlung of the magnetoactive plasma.

  8. Transport of fast electrons in lower hybrid current drive plasmas in the HT-7 tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z Y [Institute of Plasma Physics, College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Fang, D; Dai, F; Duan, Z Q; Zhu, J X; Sun, W M [Department of Physics, Yunnan Normal University, Kunming 650092 (China); Wan, B N; Shi, Y J, E-mail: chenzy1003@163.com [Institute of Plasma Physics, Chinese Academy of Sciences, Hefe 230031 (China)

    2011-04-15

    The transport of fast electrons in lower hybrid current drive (LHCD) plasmas in the HT-7 tokamak was investigated in this work. The evolution of fast electron bremsstrahlung emission profiles after switching off the lower hybrid power was analyzed. We found that the dynamics of the fast electrons is governed by the slowing-down process, and the current density profile can be controlled by LHCD in the HT-7 tokamak.

  9. Ion recombination and the response of a ``P2''-quantameter

    Science.gov (United States)

    Zieger, A.; Hughes, R. J.; Ziegler, B.

    1981-01-01

    At high power densities ion recombination influences the response of an ion chamber to X-rays. This deviation from linearity is usually called "saturation". In a National Bureau of Standards P2-type ionization chamber saturation effects have been investigated using an intense pulsed bremsstrahlung beam. The experimental results can be well represented by a general "saturation curve", which enables the determination of the true primary ionization.

  10. Radiation by energetic electrons accelerated by wave-particle interaction: a plausible mechanism for x-ray emission from the Venus mantle

    Directory of Open Access Journals (Sweden)

    R. Bingham

    2008-07-01

    Full Text Available In this paper it is argued that recently observed x-ray emission from non-magnetic planets (Dennerl et al., 2002 can be explained as a combination of bremsstrahlung and line K-shell radiation produced by the interaction of energetic electrons with the neutral atmosphere. Numerical simulations show that the modified two stream instability can generate energetic 100 eV electrons that are observed and these electrons can produce x-ray emission.

  11. Comparing Solar-Flare Acceleration of >-20 MeV Protons and Electrons Above Various Energies

    Science.gov (United States)

    Shih, Albert Y.

    2010-01-01

    A large fraction (up to tens of percent) of the energy released in solar flares goes into accelerated ions and electrons, and studies indicate that these two populations have comparable energy content. RHESSI observations have shown a striking close linear correlation between the 2.223 MeV neutron-capture gamma-ray line and electron bremsstrahlung emission >300 keV, indicating that the flare acceleration of >^20 MeV protons and >300 keV electrons is roughly proportional over >3 orders of magnitude in fluence. We show that the correlations of neutron-capture line fluence with GOES class or with bremsstrahlung emission at lower energies show deviations from proportionality, primarily for flares with lower fluences. From analyzing thirteen flares, we demonstrate that there appear to be two classes of flares with high-energy acceleration: flares that exhibit only proportional acceleration of ions and electrons down to 50 keV and flares that have an additional soft, low-energy bremsstrahlung component, suggesting two separate populations of accelerated electrons. We use RHESSI spectroscopy and imaging to investigate a number of these flares in detail.

  12. Pair production in classical Stueckelberg-Horwitz-Piron electrodynamics

    Science.gov (United States)

    Land, Martin

    2015-05-01

    We calculate pair production from bremsstrahlung as a classical effect in Stueckelberg-Horwitz electrodynamics. In this framework, worldlines are traced out dynamically through the evolution of events xμ(τ) parameterized by a chronological time τ that is independent of the spacetime coordinates. These events, defined in an unconstrained 8D phase space, interact through five τ-dependent gauge fields induced by the event evolution. The resulting theory differs in its underlying mechanics from conventional electromagnetism, but coincides with Maxwell theory in an equilibrium limit. In particular, the total mass-energy-momentum of particles and fields is conserved, but the mass-shell constraint is lifted from individual interacting events, so that the Feynman-Stueckelberg interpretation of pair creation/annihilation is implemented in classical mechanics. We consider a three-stage interaction which when parameterized by the laboratory clock x0 appears as (1) particle-1 scatters on a heavy nucleus to produce bremsstrahlung, (2) the radiation field produces a particle/antiparticle pair, (3) the antiparticle is annihilated with particle-2 in the presence of a second heavy nucleus. When parameterized in chronological time τ, the underlying process develops as (1) particle-2 scatters on the second nucleus and begins evolving backward in time with negative energy, (2) particle-1 scatters on the first nucleus and releases bremsstrahlung, (3) particle-2 absorbs radiation which returns it to forward time evolution with positive energy.

  13. Runaway studies in the ATF (Advanced Toroidal Facility) torsatron

    Energy Technology Data Exchange (ETDEWEB)

    England, A.C.; DeVan, W.R.; Eberle, C.C.; Fowler, R.H.; Gabbard, W.A.; Glowienka, J.C.; Harris, J.H.; Haste, G.R.; Kindsfather, R.R.; Morris, R.N.

    1989-01-01

    Pulsed torsatrons and heliotrons are susceptible to runaway electron formation and confinement resulting from the inherent good containment in the vacuum fields and the high loop voltages during the initiation and termination of the helical and vertical fields (''field ramping''). Because runaway electrons can cause an unacceptable level of hard X rays near the machine, a runaway suppression system was designed and included in the initial operation of the Advanced Toroidal Facility (ATF). The main component of the system is a rotating paddle that is normally left in the vacuum chamber during the field ramps. This device proved to be very effective in reducing the runaway population. Measurements of hard X rays from ATF have shown that the runaways are produced primarily during the field ramping but that usually a small steady-state runaway component is also present during the ''flat-top'' portion of the fields. The paddle is the main source of the hard X rays (thick-target bremsstrahlung), although other objects in the vacuum chamber also serve as targets for the runaways at various times. The maximum X-ray energy found by pulse height analysis is /approximately/12--15 MeV; the mean energy appears to be a few mega-electron-volts. A noticeable forward peaking of the bremsstrahlung from the paddle is evident. The limiters do not appear to be major sources of bremsstrahlung. 17 refs., 14 figs.

  14. Isomer ratios for products of photonuclear reactions on 121Sb

    Science.gov (United States)

    Bezshyyko, Oleg; Dovbnya, Anatoliy; Golinka-Bezshyyko, Larisa; Kadenko, Igor; Vodin, Oleksandr; Olejnik, Stanislav; Tuller, Gleb; Kushnir, Volodymyr; Mitrochenko, Viktor

    2017-09-01

    Over the past several years various preequilibrium model approaches for nuclear reactions were developed. Diversified detailed experimental data in the medium excitation energy region for nucleus are needed for reasonable selection among these theoretical models. Lack of experimental data in this energy region does essentially limit the possibilities for analysis and comparison of different preequilibrium theoretical models. For photonuclear reactions this energy region extends between bremsstrahlung energies nearly 30-100 MeV. Experimental measurements and estimations of isomer ratios for products of photonuclear reactions with multiple particle escape on antimony have been performed using bremsstrahlung with end-point energies 38, 43 and 53 MeV. Method of induced activity measurement was applied. For acquisition of gamma spectra we used HPGe spectrometer with 20% efficiency and energy resolution 1.9 keV for 1332 keV gamma line of 60Co. Linear accelerator of electrons LU-40 was a source of bremsstrahlung. Energy resolution of electron beam was about 1% and mean current was within (3.8-5.3) μA.

  15. Characteristics of a heavy water photoneutron source in boron neutron capture therapy

    Science.gov (United States)

    Danial, Salehi; Dariush, Sardari; M. Salehi, Jozani

    2013-07-01

    Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator's treatment head, patient's body, and treatment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D2O target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy (BNCT) application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Evaluation of the heavy water photonuclear source.

  16. Monte Carlo simulation of PET and SPECT imaging of {sup 90}Y

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Akihiko, E-mail: takahsr@hs.med.kyushu-u.ac.jp; Sasaki, Masayuki [Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Himuro, Kazuhiko; Yamashita, Yasuo; Komiya, Isao [Division of Radiology, Department of Medical Technology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Baba, Shingo [Department of Clinical Radiology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan)

    2015-04-15

    Purpose: Yittrium-90 ({sup 90}Y) is traditionally thought of as a pure beta emitter, and is used in targeted radionuclide therapy, with imaging performed using bremsstrahlung single-photon emission computed tomography (SPECT). However, because {sup 90}Y also emits positrons through internal pair production with a very small branching ratio, positron emission tomography (PET) imaging is also available. Because of the insufficient image quality of {sup 90}Y bremsstrahlung SPECT, PET imaging has been suggested as an alternative. In this paper, the authors present the Monte Carlo-based simulation–reconstruction framework for {sup 90}Y to comprehensively analyze the PET and SPECT imaging techniques and to quantitatively consider the disadvantages associated with them. Methods: Our PET and SPECT simulation modules were developed using Monte Carlo simulation of Electrons and Photons (MCEP), developed by Dr. S. Uehara. PET code (MCEP-PET) generates a sinogram, and reconstructs the tomography image using a time-of-flight ordered subset expectation maximization (TOF-OSEM) algorithm with attenuation compensation. To evaluate MCEP-PET, simulated results of {sup 18}F PET imaging were compared with the experimental results. The results confirmed that MCEP-PET can simulate the experimental results very well. The SPECT code (MCEP-SPECT) models the collimator and NaI detector system, and generates the projection images and projection data. To save the computational time, the authors adopt the prerecorded {sup 90}Y bremsstrahlung photon data calculated by MCEP. The projection data are also reconstructed using the OSEM algorithm. The authors simulated PET and SPECT images of a water phantom containing six hot spheres filled with different concentrations of {sup 90}Y without background activity. The amount of activity was 163 MBq, with an acquisition time of 40 min. Results: The simulated {sup 90}Y-PET image accurately simulated the experimental results. PET image is visually

  17. The Chandra Source Catalog 2.0: Spectral Properties

    Science.gov (United States)

    McCollough, Michael L.; Siemiginowska, Aneta; Burke, Douglas; Nowak, Michael A.; Primini, Francis Anthony; Laurino, Omar; Nguyen, Dan T.; Allen, Christopher E.; Anderson, Craig S.; Budynkiewicz, Jamie A.; Chen, Judy C.; Civano, Francesca Maria; D'Abrusco, Raffaele; Doe, Stephen M.; Evans, Ian N.; Evans, Janet D.; Fabbiano, Giuseppina; Gibbs, Danny G., II; Glotfelty, Kenny J.; Graessle, Dale E.; Grier, John D.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; Houck, John C.; Lauer, Jennifer L.; Lee, Nicholas P.; Martínez-Galarza, Juan Rafael; McDowell, Jonathan C.; Miller, Joseph; McLaughlin, Warren; Morgan, Douglas L.; Mossman, Amy E.; Nichols, Joy S.; Paxson, Charles; Plummer, David A.; Rots, Arnold H.; Sundheim, Beth A.; Tibbetts, Michael; Van Stone, David W.; Zografou, Panagoula; Chandra Source Catalog Team

    2018-01-01

    The second release of the Chandra Source Catalog (CSC) contains all sources identified from sixteen years' worth of publicly accessible observations. The vast majority of these sources have been observed with the ACIS detector and have spectral information in 0.5-7 keV energy range. Here we describe the methods used to automatically derive spectral properties for each source detected by the standard processing pipeline and included in the final CSC. The sources with high signal to noise ratio (exceeding 150 net counts) were fit in Sherpa (the modeling and fitting application from the Chandra Interactive Analysis of Observations package) using wstat as a fit statistic and Bayesian draws method to determine errors. Three models were fit to each source: an absorbed power-law, blackbody, and Bremsstrahlung emission. The fitted parameter values for the power-law, blackbody, and Bremsstrahlung models were included in the catalog with the calculated flux for each model. The CSC also provides the source energy fluxes computed from the normalizations of predefined absorbed power-law, black-body, Bremsstrahlung, and APEC models needed to match the observed net X-ray counts. For sources that have been observed multiple times we performed a Bayesian Blocks analysis will have been performed (see the Primini et al. poster) and the most significant block will have a joint fit performed for the mentioned spectral models. In addition, we provide access to data products for each source: a file with source spectrum, the background spectrum, and the spectral response of the detector. Hardness ratios were calculated for each source between pairs of energy bands (soft, medium and hard). This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.

  18. On the Nature of Orion Source I

    Science.gov (United States)

    Báez-Rubio, A.; Jiménez-Serra, I.; Martín-Pintado, J.; Zhang, Q.; Curiel, S.

    2018-01-01

    The Kleinmann–Low nebula in Orion, the closest region of massive star formation, harbors Source I, whose nature is under debate. Knowledge of this source may have profound implications for our understanding of the energetics of the hot core in Orion KL since it might be the main heating source in the region. The spectral energy distribution of this source in the radio is characterized by a positive spectral index close to 2, which is consistent with (i) thermal bremsstrahlung emission of ionized hydrogen gas produced by a central massive protostar, or (ii) photospheric bremsstrahlung emission produced by electrons when deflected by the interaction with neutral and molecular hydrogen like Mira-like variable stars. If ionized hydrogen gas were responsible for the observed continuum emission, its modeling would predict detectable emission from hydrogen radio recombination lines (RRLs). However, our SMA observations were obtained with a high enough sensitivity to rule out that the radio continuum emission arises from a dense hypercompact H II region because the H26α line would have been detected, in contrast with our observations. To explain the observational constraints, we investigate further the nature of the radio continuum emission from source I. We have compared available radio continuum data with the predictions from our upgraded non-LTE 3D radiative transfer model, MOdel for REcombination LInes, to show that radio continuum fluxes and sizes can only be reproduced by assuming both dust and bremsstrahlung emission from neutral gas. The dust emission contribution is significant at ν ≥ 43 GHz. In addition, our RRL peak intensity predictions for the ionized metals case are consistent with the nondetection of Na and K RRLs at millimeter and submillimeter wavelengths.

  19. 3D dosimetry estimation for selective internal radiation therapy (SIRT) using SPECT/CT images: a phantom study

    Science.gov (United States)

    Debebe, Senait A.; Franquiz, Juan; McGoron, Anthony J.

    2015-03-01

    Selective Internal Radiation Therapy (SIRT) is a common way to treat liver cancer that cannot be treated surgically. SIRT involves administration of Yttrium - 90 (90Y) microspheres via the hepatic artery after a diagnostic procedure using 99mTechnetium (Tc)-macroaggregated albumin (MAA) to detect extrahepatic shunting to the lung or the gastrointestinal tract. Accurate quantification of radionuclide administered to patients and radiation dose absorbed by different organs is of importance in SIRT. Accurate dosimetry for SIRT allows optimization of dose delivery to the target tumor and may allow for the ability to assess the efficacy of the treatment. In this study, we proposed a method that can efficiently estimate radiation absorbed dose from 90Y bremsstrahlung SPECT/CT images of liver and the surrounding organs. Bremsstrahlung radiation from 90Y was simulated using the Compton window of 99mTc (78keV at 57%). 99mTc images acquired at the photopeak energy window were used as a standard to examine the accuracy of dosimetry prediction by the simulated bremsstrahlung images. A Liqui-Phil abdominal phantom with liver, stomach and two tumor inserts was imaged using a Philips SPECT/CT scanner. The Dose Point Kernel convolution method was used to find the radiation absorbed dose at a voxel level for a three dimensional dose distribution. This method will allow for a complete estimate of the distribution of radiation absorbed dose by tumors, liver, stomach and other surrounding organs at the voxel level. The method provides a quantitative predictive method for SIRT treatment outcome and administered dose response for patients who undergo the treatment.

  20. Photoneutron source based on a compact 10 MeV betatron

    Science.gov (United States)

    Chakhlov, V. L.; Bell, Z. W.; Golovkov, V. M.; Shtein, M. M.

    1999-02-01

    Accelerator-based photoneutron sources have enjoyed wide use and offer the advantages of long term stability, ease of control and absence of radioactive materials. We report here measurements of the yield of photoneutrons from a neutron generator using a compact betatron. Electrons were accelerated to energies up to 10 MeV and produced a bremsstrahlung beam with a dose rate of 0.16 Gy/min (at 10 MeV, 1 m from the bremsstrahlung target) to irradiate LiD, Be, depleted U, and Pb neutron-producing targets. The angular distributions of photoneutrons produced by bremsstrahlung beams were measured with a "long" counter and integrated to determine neutron yield. In addition, neutron time of flight spectra were recorded from all targets using a 15.5 m flight path perpendicular to the photon beam. The maximum observed yields were 4.6×10 7 n/s obtained with 1 kg of LiD, 5.7×10 7 n/s from a 3.3 kg Be block, 6.2×10 6 n/s from 1.5 kg of depleted U, and 7.0×10 6 n/s from 10.7 kg of Pb. Optimization of target dimensions, shape, and positioning is expected to increase the yield from the LiD target by a factor of 35, while optimization of the other targets is expected to yield at most a factor of 10. With the increased yield and a deuteride target, this compact betatron-based system could find application in the interrogation of waste containers for fissile material.

  1. Photoneutron source based on a compact 10 MeV betatron

    Energy Technology Data Exchange (ETDEWEB)

    Chakhlov, V.L. [Institute of Introscopy, Tomsk Polytechnic University, Tomsk 634028 (Russian Federation); Bell, Z.W. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN 37831 (United States); Golovkov, V.M. [Institute of Nuclear Physics, Tomsk Polytechnic University, Tomsk 634050 (Russian Federation); Shtein, M.M. [Institute of Introscopy, Tomsk Polytechnic University, Tomsk 634028 (Russian Federation)

    1999-02-11

    Accelerator-based photoneutron sources have enjoyed wide use and offer the advantages of long term stability, ease of control and absence of radioactive materials. We report here measurements of the yield of photoneutrons from a neutron generator using a compact betatron. Electrons were accelerated to energies up to 10 MeV and produced a bremsstrahlung beam with a dose rate of 0.16 Gy/min (at 10 MeV, 1 m from the bremsstrahlung target) to irradiate LiD, Be, depleted U, and Pb neutron-producing targets. The angular distributions of photoneutrons produced by bremsstrahlung beams were measured with a 'long' counter and integrated to determine neutron yield. In addition, neutron time of flight spectra were recorded from all targets using a 15.5 m flight path perpendicular to the photon beam. The maximum observed yields were 4.6x10{sup 7} n/s obtained with 1 kg of LiD, 5.7x10{sup 7} n/s from a 3.3 kg Be block, 6.2x10{sup 6} n/s from 1.5 kg of depleted U, and 7.0x10{sup 6} n/s from 10.7 kg of Pb. Optimization of target dimensions, shape, and positioning is expected to increase the yield from the LiD target by a factor of 35, while optimization of the other targets is expected to yield at most a factor of 10. With the increased yield and a deuteride target, this compact betatron-based system could find application in the interrogation of waste containers for fissile material.

  2. Photon dose produced by a high-intensity laser on a solid target

    Science.gov (United States)

    Compant La Fontaine, A.

    2014-08-01

    When a high-intensity laser pulse hits a solid target, its pedestal creates a preplasma. The interaction of the main laser pulse, linearly polarized, with this preplasma produces relativistic electrons. These electrons subsequently penetrate inside the target, with high atomic number, and produce bremsstrahlung emission, which constitutes an x-ray source that may be used in various applications such as radiography of high area density objects, photonuclear studies or positron production. This x-ray source is mainly defined by its photon dose, which depends upon the laser, preplasma and target characteristics. In new facilities the radioprotection layout design can be obtained by numerical simulations, which are somewhat tedious. A simple model giving the photon dose per laser energy unit is obtained by using the mean bremsstrahlung cross section of electrons interacting with the atoms of the conversion target. It is expressed versus the fraction ηel of the laser energy absorbed into the forward hot electrons, their mean kinetic energy E, the photon lobe emission mean angular aperture \\bar{{\\theta}} and the target characteristics, i.e. thickness, element, atomic mass and atomic number. The parameters ηel, E and \\bar{{\\theta}} are analysed by applying the energy and momentum flux conservation laws during the laser-plasma interaction in the relativistic regime in an underdense and overdense plasma, including the hole-boring effect. In addition, these quantities are parametrized versus the normalized laser vector potential a0 and the preplasma scale length Lp by using a full set of numerical simulations, in the laser intensity domain 1018-1021 W cm-2 and preplasma scale length range 0.03-400µm. These simulations are done in two- and three-dimensional geometry with the CALDER particle-in-cell code, which computes the laser-plasma interaction, and with the MCNP Monte Carlo code, which calculates the bremsstrahlung emission. The present model is compared with the

  3. Search for gluons in e/sup +/e/sup -/ annihilation

    CERN Document Server

    Ellis, Jonathan Richard; Ross, Graham G

    1976-01-01

    The authors study the deviations to be expected at high energies from the recently observed two jet structure of hadronic final states in e /sup +/e/sup -/ annihilation. Motivated by the approximate validity of the naive parton model and by asymptotic freedom they suggest that hard gluon bremsstrahlung may be the dominant source of hadrons with large momenta transverse to the main jet axes. This process should give rise to three-jet final states. These may be observable at the highest SPEAR or DORIS energies, and should be important at the higher PETRA or PEP energies. (15 refs).

  4. Influence of the angular scattering of electrons on the runaway threshold in air

    DEFF Research Database (Denmark)

    Chanrion, O.; Bonaventura, Z.; Bourdon, A.

    2016-01-01

    The runaway electron mechanism is of great importance for the understanding of the generation of x- and gamma rays in atmospheric discharges. In 1991, terrestrial gamma-ray flashes (TGFs) were discovered by the Compton Gamma-Ray Observatory. Those emissions are bremsstrahlung from high energy ele...... scattering is not valid below 1 MeV where the runaway threshold usually is defined. These results are important for the thermal runaway and the runaway electron avalanche discharge mechanisms suggested to participate in the TGF generation....

  5. Candidate for a Z boson decaying into leptons, produced in association with jets and collected at the ATLAS Experiment

    CERN Multimedia

    ATLAS, Experiment

    2014-01-01

    Candidate for Z→μμ decay, with the Z produced in association with three jets, collected on 10 May 2010. In the xy projection, the 144 GeV transverse momentum of the Z boson is especially apparent. The muon transverse momenta are 96 GeV and 68 GeV, and their invariant mass is 79 GeV. The harder muon has left a significant energy deposit (see lego-plot projection), presumably through bremsstrahlung; this is not included in the standard Z mass calculation. The jet transverse energies are 168, 105, and 45 GeV.

  6. New method for taking into account radiative events in the MOLLER inclusive experiment

    Science.gov (United States)

    Zykunov, V. A.

    2017-07-01

    A new method ( N-method) for taking into account radiative events in inclusive polarized experiments that, in principle, makes no use of an unphysical separation into soft-and hard-photon regions is demonstrated. A procedure for taking into account bremsstrahlung in theMOLLER forthcoming ultraprecise experiment at the Thomas Jefferson Laboratory is developed on the basis of this method. The algorithm of the method is described in detail, and the results obtained by means of the N method are compared with the results of applying traditional methods.

  7. Charge asymmetries in e{sup +}e{sup -{yields}{pi}+{pi}-{gamma}} at the {phi} resonance

    Energy Technology Data Exchange (ETDEWEB)

    Gallegos, A. [Departamento de Ciencias Exactas y Tecnologia, Centro Universitario de los Lagos, Universidad de Guadalajara, Enrique Diaz de Leon 1144, Colonia Paseos de la Montana, 47460, Lagos de Moreno, Jalisco (Mexico); Lucio, J.L.; Moreno, G. [Departamento de Fisica, Division de Ciencias e Ingenierias, Universidad de Guanajuato, Campus Leon, Lomas del Bosque 103, Fraccionamiento Lomas del Campestre, 37150, Leon, Guanajuato (Mexico); Napsuciale, M., E-mail: mauro@fisica.ugto.m [Departamento de Fisica, Division de Ciencias e Ingenierias, Universidad de Guanajuato, Campus Leon, Lomas del Bosque 103, Fraccionamiento Lomas del Campestre, 37150, Leon, Guanajuato (Mexico)

    2010-10-11

    We consider the forward-backward pion charge asymmetry for the e{sup +}e{sup -{yields}{pi}+{pi}-{gamma}} process. At tree level we consider bremsstrahlung and double resonance contributions. Although the latter contribution is formally sub-leading, it is enhanced at low dipion invariant mass due to {rho} resonant effects. We consider also four alternative models to describe the final state radiation at the loop level: Resonance Chiral Perturbation Theory, Unitarized Chiral Perturbation Theory, Kaon Loop Model and Linear Sigma Model. The last three models yield results compatible with experimental data. The Kaon Loop Model requires an energy dependent phase to achieve the agreement.

  8. First Results from The GlueX Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Curtis [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2016-05-01

    The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic and liquid hydrogen targets, and much of the detector has been commissioned. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed, including exclusive production of pi^0, eta and omega mesons. Linearly-polarized photons were successfully produced through coherent bremsstrahlung and polarization transfer to the ρ has been observed.

  9. Spaceresolved determination the features and parameters of plasmoids obtained by gyromagnetic autoresonance.

    Science.gov (United States)

    Chuprov, Denis; Andreev, Victor; Umnov, Anatoliy; Novitskii, Andrey

    2015-09-01

    Experiment and computer simulation with relativistic plasma obtained under gyromagnetic autoresonance (GA) condition are described. X-ray spectrometry, radiometry and imaging methods were applied to investigate obtained plasmoids. Energies of measured bremsstrahlung spectrums up to 0,5 MeV were observed. Investigation of the spatial anisotropy of produced X-ray radiation gave information about the plasmoid shape, localization and movement. The complex motion of the belt shaped relativistic plasmoid can be presented as rotation of the driving center around trap symmetry axis. Obtained experimental results are in good quantitative agreement with numerical simulations of GA process by particles-in-cell model.

  10. Dependence of monojet and dijet production on the energy detection threshold in ultrarelativistic collisions of nuclei

    CERN Document Server

    Lokhtin, Igor P; Snigirev, A M

    1999-01-01

    On the basis of model concepts, the ratio of the monojet yield to the dijet yield in ultrarelativistic nucleus-nucleus collisions has been studied as a function of the energy threshold for jet detection. A comparative analysis of the contributions to the cross section for monojet production due to gluon bremsstrahlung prior to the primary hard parton-parton collision and due to the asymmetric energy losses of dijets in quark-gluon plasma whose formation is expected in central heavy-ion collisions at the energies of the future colliders RHIC and LHC has been performed. (35 refs).

  11. ATA diagnostic beam dump conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    1981-09-01

    A diagnostic beam dump, able to withstand 72,000 pulses (10 kA, 50 MeV/pulse) per shift was designed and analyzed. The analysis shows that the conceptual beam dump design consisting of 80 vitreous carbon plate-foam elements is able to withstand the thermal and mechanical stresses generated. X-rays produced by bremsstrahlung are absorbed by a three element copper plate-foam x-ray absorber. Cooling between bursts of electron pulses is provided by pressurized helium.

  12. Dosimetry of Low-Energy Beta Radiation

    DEFF Research Database (Denmark)

    Borg, Jette

    Useful techniques and procedures for derermination of absorbed doses from exposure in a low-energy beta radiation were studied and evaluated. The four techniques included were beta spectrometry, extrapolation chamber dosimetry, Monte Carlo (MC) calculations, and exoelectron dosimetry. As a typical...... low-energy beta radiation field a moderated spectrum from a carbon-14 source was used. The measured responce of a Si(Li) detector to photons (bremsstrahlung) showed fine agreemant with the MC calculated photon response, whereas the difference between measured and MC calculated response to electrons...

  13. The Spectrometer/Telescope for Imaging X-rays on Solar Orbiter: Flight design, challenges and trade-offs

    Energy Technology Data Exchange (ETDEWEB)

    Krucker, S. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Space Sciences Laboratory, UC Berkeley (United States); Bednarzik, M. [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, Villigen (Switzerland); Grimm, O., E-mail: oliver.grimm@phys.ethz.ch [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); ETH Zürich (Switzerland); Hurford, G.J. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Space Sciences Laboratory, UC Berkeley (United States); Limousin, O.; Meuris, A. [CEA Saclay (France); Orleański, P. [University of Applied Sciences and Arts Northwestern Switzerland, Windisch (Switzerland); Space Research Center of the Polish Academy of Sciences (CBK PAN), Warsaw (Poland); Seweryn, K.; Skup, K.R. [Space Research Center of the Polish Academy of Sciences (CBK PAN), Warsaw (Poland)

    2016-07-11

    STIX is the X-ray spectral imaging instrument on-board the Solar Orbiter space mission of the European Space Agency, and together with nine other instruments will address questions of the interaction between the Sun and the heliosphere. STIX will study the properties of thermal and accelerated electrons near the Sun through their Bremsstrahlung X-ray emission, addressing in particular the emission from flaring regions on the Sun. The design phase of STIX has been concluded. This paper reports the final flight design of the instrument, focusing on design challenges that were faced recently and how they were addressed.

  14. Direct measurement of energetic electrons coupling to an imploding low-adiabat inertial confinement fusion capsule.

    Science.gov (United States)

    Döppner, T; Thomas, C A; Divol, L; Dewald, E L; Celliers, P M; Bradley, D K; Callahan, D A; Dixit, S N; Harte, J A; Glenn, S M; Haan, S W; Izumi, N; Kyrala, G A; LaCaille, G; Kline, J K; Kruer, W L; Ma, T; MacKinnon, A J; McNaney, J M; Meezan, N B; Robey, H F; Salmonson, J D; Suter, L J; Zimmerman, G B; Edwards, M J; MacGowan, B J; Kilkenny, J D; Lindl, J D; Van Wonterghem, B M; Atherton, L J; Moses, E I; Glenzer, S H; Landen, O L

    2012-03-30

    We have imaged hard x-ray (>100 keV) bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. We measure 570 J in electrons with E>100 keV impinging on the fusion capsule under ignition drive conditions. This translates into an acceptable increase in the adiabat α, defined as the ratio of total deuterium-tritium fuel pressure to Fermi pressure, of 3.5%. The hard x-ray observables are consistent with detailed radiative-hydrodynamics simulations, including the sourcing and transport of these high energy electrons.

  15. X-ray Emission from the Radio Jet in 3C 120

    DEFF Research Database (Denmark)

    Harris, D. E.; Hjorth, J.; Sadun, A. C.

    1999-01-01

    We report the discovery of X-ray emission from a radio knot at a projected distance of 25" from the nucleus of the Seyfert galaxy, 3C 120. The data were obtained with the ROSAT High Resolution Imager (HRI). Optical upper limits for the knot preclude a simple power law extension of the radio...... spectrum and we calculate some of the physical parameters for thermal bremsstrahlung and synchrotron self-Compton models. We conclude that no simple model is consistent with the data but if the knot contains small regions with flat spectra, these could produce the observed X-rays (via synchrotron emission...

  16. Beam-gas background calculation for DEAR

    Energy Technology Data Exchange (ETDEWEB)

    Guiducci, S. [INFN, Frascati (Italy). Laboratori Nazionali di Frascati; Iliescu, M. A. [IFIN-HH, Bucharest (Romania)

    1997-01-01

    The present paper describes the results obtained from a Monte Carlo simulation of the particles lost in the DAY-ONE Interaction Region (IR) of the DAFNE machine. Coulomb scattering on the nuclei of residual gas and beam-gas Bremsstrahlung, which are the main sources of background in the initial phase of machine operation, were considered. A ray-tracking program (TURTLE) was used to follow the trajectories of the particles in the rings and to evaluate the number of particles that hit the vacuum chamber in the interaction region.

  17. First results of the CROME experiment

    CERN Document Server

    Smida, R; Engel, R; Haungs, A; Huege, T; Kampert, K -H; Klages, H; Kleifges, M; Kroemer, O; Mathys, S; Rautenberg, J; Riegel, M; Roth, M; Salamida, F; Schieler, H; Stasielak, J; Unger, M; Weber, M; Werner, F; Wilczynski, H; Wochele, J

    2011-01-01

    It is expected that a radio signal in the microwave range is produced in the atmosphere due to molecular bremsstrahlung initiated by extensive air showers. The CROME (Cosmic-Ray Observation via Microwave Emission) experiment was built to search for this microwave signal. Radiation from the atmosphere is monitored in the extended C band (3.4--4.2 GHz) in coincidence with showers detected by the KASCADE-Grande experiment. The detector setup consists of several parabolic antennas and fast read-out electronics. The sensitivity of the detector has been measured with different methods. First results after half a year of data taking are presented.

  18. Shielding Design Aspects of SR Beamlines for 3-GeV And 8-GeV Class Synchrotron Radiation Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Yoshihiro; /JAERI-RIKEN, Hyogo; Liu, James C.; Rokni, Sayed; /SLAC

    2007-09-24

    Differences in synchrotron radiation beamline shielding design between the facilities of 3 GeV class and 8 GeV class are discussed with regard to SLAC SSRL and SPring-8 beamlines. Requirements of beamline shielding as well as the accelerator shielding depend on the stored electron energy, and here some factors in beamline shielding depending on the stored energy in particular, are clarified, namely the effect of build up, the effect of double scattering of photons at branch beamlines, and the spread of gas bremsstrahlung.

  19. Effective photoexcitation cross section of 115In(γ,γ′115mIn from photoactivation data

    Directory of Open Access Journals (Sweden)

    Versteegen M.

    2016-01-01

    Full Text Available Photoexcitation yields of the 115mIn metastable state were measured with Bremsstrahlung γ beams over a range of endpoint energies between 4.5 and 18 MeV. An effective cross section of the 115In(γ,γ′115mIn photoexcitation cross section was determinedto reproduce the data. This cross section is built from a cross section calculated with the TALYS code, to which an enhancement is added at about 8.5 MeV.

  20. Transport Processes in High Temperature QCD Plasmas

    Science.gov (United States)

    Hong, Juhee

    The transport properties of high temperature QCD plasmas can be described by kinetic theory based on the Boltzmann equation. At a leading-log approximation, the Boltzmann equation is reformulated as a Fokker-Planck equation. First, we compute the spectral densities of Tµν and Jµ by perturbing the system with weak gravitational and electromagnetic fields. The spectral densities exhibit a smooth transition from free-streaming quasi-particles to hydrodynamics. This transition is analyzed with hydrodynamics and diffusion equation up to second order. We determine all of the first and second order transport coefficients which characterize the linear response in the hydrodynamic regime. Second, we simulate the wake of a heavy quark moving through the plasmas. At long distances, the energy density and flux distributions show sound waves and a diffusion wake. The kinetic theory calculations based on the Boltzmann equation at weak coupling are compared to the strong coupling results given by the AdS/CFT correspondence. By using the hard-thermal-loop effective theory, we determine the photon emission rate at next-to-leading order (NLO), i.e., at order g2mD /T. There are three mechanisms which contribute to the leading-order photon emission: (2 ↔ 2) elastic scatterings, (1 ↔ 2) collinear bremsstrahlung, and (1 ↔ 1) quark-photon conversion due to soft fermion exchange. At NLO, these three mechanisms are not completely independent. When the transverse momentum between quark and photon becomes soft, the Compton scattering with a soft gluon reduces to wide-angle bremsstrahlung. Similarly, bremsstrahlung reduces to the quark-photon conversion process when the photon carries most of the incoming momentum. Therefore, the rates should be matched to determine the wide-angle NLO correction. Collinear bremsstrahlung can be accounted for by solving an integral equation which corresponds to summing ladder diagrams. With O(g) corrections in the collision kernel and the asymptotic

  1. Lectures in relativistic quantum mechanics an introductory course for postgraduates in particle physics

    CERN Document Server

    Azfar, Farrukh

    2017-01-01

    This book is based on a series of lectures taught by the author to all incoming first year Oxford University postgraduates in experimental particle physics. It begins by deriving the Dirac equation and incorporating the electro-magnetic interaction and calculating several bread and butter processes at tree level using the Feynman Stueckelberg approach: Mott scattering, electron-electron scattering, electron-positron scattering, Compton scattering, Bremsstrahlung and electron-positron to muon-anti-muon. The intention is for the student to become fluent in detail with all the steps leading to the calculation of these processes. Every step is motivated using the most basic arguments.

  2. Spectral diagnostics of a vapor-plasma plume produced during welding titanium with a high-power ytterbium fiber laser

    Science.gov (United States)

    Uspenskiy, S. A.; Petrovskiy, V. N.; Bykovskiy, D. P.; Mironov, V. D.; Prokopova, N. M.; Tret'yakov, E. V.

    2015-03-01

    This work is devoted to the research of welding plume during high power ytterbium fiber laser welding of a titanium alloy in the Ar shielding gas environment. High speed video observation of a vapor-plasma plume for visualization of processes occurring at laser welding was carried out. The coefficient of the inverse Bremsstrahlung absorption of laser radiation is calculated for a plasma welding plume by results of spectrometer researches. The conclusion deals with the impact of plasma on a high-power fiber laser radiation.

  3. A modified theoretical Σ − D relation for supernova remnants: I. The case of constant temperature within the supernova remnant

    Directory of Open Access Journals (Sweden)

    Urošević Dejan V.

    2003-01-01

    Full Text Available We present a modification of the theoretical Σ − D relation for supernova remnants (SNRs in the adiabatic expansion phase. This modification is based on the convolution of the relation first derived by Shklovsky with the Σ − D relation derived in this paper for thermal bremsstrahlung radiation from the ionized gas cloud. We adopt McKee & Ostriker’s model for the components of the interstellar medium as part of our derivation. The modified Shklovsky theory agrees well with empirical results. Kesteven’s modified theoretical relation gives the best agreement with the updated Galactic empirical Σ − D relation.

  4. Rare four-leptonic B-decays with light leptons in the final state in the Standard Model

    Science.gov (United States)

    Danilina, Anna; Nikitin, Nikolai

    2017-10-01

    We present predictions for the four-leptonic decays of B--mesons with three light charged leptons and one neutrino in the final states. We obtain the branching ratio for decay at the level 1.3 × 10-7 taking into account the photon emission from the u- and b- valence quarks of B- -meson and the Bremsstrahlung. The contribution of the virtual photon was calculated using the Vector Meson Dominance model (VMD). As a next step we present prediction for branching ratio of the decay and the estimation for .

  5. Collective Flow and Mach Cones with transport

    Directory of Open Access Journals (Sweden)

    Xu Z.

    2011-04-01

    Full Text Available Fast thermalization and a strong build up of elliptic flow of QCD matter were investigated within the pQCD based 3+1 dimensional parton transport model BAMPS including bremsstrahlung 2 ↔ 3 processes. Within the same framework quenching of gluonic jets in Au+Au collisions at RHIC can be understood. The development of conical structure by gluonic jets is investigated in a static box for the regimes of small and large dissipation. Furthermore we demonstrate two different approaches to extract the shear viscosity coefficient η from a microscopical picture.

  6. Atomic and free electrons in a strong light field

    CERN Document Server

    Fedorov, Mikhail V

    1997-01-01

    This book presents and describes a series of unusual and striking strong-field phenomena concerning atoms and free electrons. Some of these phenomena are: multiphoton stimulated bremsstrahlung, free-electron lasers, wave-packet physics, above-threshold ionization, and strong-field stabilization in Rydberg atoms. The theoretical foundations and causes of the phenomena are described in detail, with all the approximations and derivations discussed. All the known and relevant experiments are described too, and their results are compared with those of the existing theoretical models.An extensive ge

  7. Status of soft photon production in hadronic interactions

    CERN Document Server

    Spyropoulou-Stassinaki, M

    2000-01-01

    A review of experimental results on soft photon production in hadronic collisions is presented. Results from WA27, NA22, HELIOS, WA83, WA91 experiments are discussed. A more detailed presentation of SOPHIE/WA83 and WA91 experimental analysis of data on pi /sup -/p at 280 GeV/c interactions at the CERN OMEGA spectrometer is given. Both experiments show a similar excess of soft photons over the inner hadronic Bremsstrahlung, concentrated mainly, in the energy region 0.20) but not with HELIOS results with photons measured at Y/sub cms/

  8. Advances in X-ray spectroscopy contributions in honour of professor Y. Cauchois

    CERN Document Server

    Bonnelle, C

    1982-01-01

    Advances in X-Ray Spectroscopy covers topics relevant to the advancement of X-ray spectroscopy technology. The book is a collection of papers written by specialists in X-ray spectroscopy and pays tribute to the scientific work of Prof. Yvette Cauchois. The text is organized into four parts. Part I covers the analysis of X-ray transitions between atomic levels and relativistic theories of X-ray emission satellites and electron BremsStrahlung. Part II reviews the means provided by X-ray spectroscopy for the determination of the electronic structure of solids, while Part III discusses methods of

  9. Backscatter of hard X-rays in the solar atmosphere. [Calculating the reflectance of solar x ray emission

    Science.gov (United States)

    Bai, T.; Ramaty, R.

    1977-01-01

    The solar photosphere backscatters a substantial fraction of the hard X rays from solar flares incident upon it. This reflection was studied using a Monte Carlo simulation which takes into account Compton scattering and photo-electric absorption. Both isotropic and anisotropic X ray sources are considered. The bremsstrahlung from an anisotropic distribution of electrons are evaluated. By taking the reflection into account, the inconsistency is removed between recent observational data regarding the center-to-limb variation of solar X ray emission and the predictions of models in which accelerated electrons are moving down toward the photosphere.

  10. 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

  11. Cherenkov Radiation from Jets in Heavy-ion Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Volker; Majumder, Abhijit; Wang, Xin-Nian

    2005-07-26

    The possibility of Cherenkov-like gluon bremsstrahlung in dense matter is studied. We point out that the occurrence of Cherenkov radiation in dense matter is sensitive to the presence of partonic bound states. This is illustrated by a calculation of the dispersion relation of a massless particle in a simple model in which it couples to two different massive resonance states. We further argue that detailed spectroscopy of jet correlations can directly probe the index of refraction of this matter, which in turn will provide information about the mass scale of these partonic bound states.

  12. Innovative high pressure gas MEM's based neutron detector for ICF and active SNM detection.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Shawn Bryan; Derzon, Mark Steven; Renzi, Ronald F.; Chandler, Gordon Andrew

    2007-12-01

    An innovative helium3 high pressure gas detection system, made possible by utilizing Sandia's expertise in Micro-electrical Mechanical fluidic systems, is proposed which appears to have many beneficial performance characteristics with regards to making these neutron measurements in the high bremsstrahlung and electrical noise environments found in High Energy Density Physics experiments and especially on the very high noise environment generated on the fast pulsed power experiments performed here at Sandia. This same system may dramatically improve active WMD and contraband detection as well when employed with ultrafast (10-50 ns) pulsed neutron sources.

  13. Elektron-Alüminyum Etkileşiminde Depolanan Enerjinin Hedef Kalınlığı ile Değişimi

    Directory of Open Access Journals (Sweden)

    Zehra Nur DEMİRCİ

    2014-07-01

    Full Text Available Accelerators, which are high technology, has been setup in a large number of facility in the world. The accelerated beams can be used in particle or nuclear physics experiment. Thickness of target, which used in production bremsstrahlung photon by accelerated electrons, is important. In this study, the variation of energy deposition with target thickness has been investigated due to interaction of 8 MeV energy accelerated electron beam with aluminum target at different thicknesses. Depending the target thickness of energy deposition on Al target has been simulated using FLUKA code. The energy deposition on the target has increased with increasing thickness of target material

  14. Solar axion flux from the axion-electron coupling

    Energy Technology Data Exchange (ETDEWEB)

    Redondo, Javier, E-mail: redondo@mpp.mpg.de [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, Theresienstr. 37, D-80333 München (Germany)

    2013-12-01

    In non-hadronic axion models, where axions couple to electrons at tree level, the solar axion flux is completely dominated by the ABC reactions (Atomic recombination and deexcitation, Bremsstrahlung and Compton). In this paper the ABC flux is computed from available libraries of monochromatic photon radiative opacities (OP, LEDCOP and OPAS) by exploiting the relations between axion and photon emission cross sections. These results turn to be ∼ 30% larger than previous estimates due to atomic recombination (free-bound electron transitions) and deexcitation (bound-bound), which where not previously taken into account.

  15. Trajectories of high energy electrons in a plasma focus

    Science.gov (United States)

    Harries, W. L.; Lee, J. H.; Mcfarland, D. R.

    1978-01-01

    Measurements are made of high-energy electron trajectories in a plasma focus as functions of position, time, energy, and angle of emission. The spatial resolution of the X-ray emission shows that low-energy X-rays are emitted from the anode surface. It is also suggested that the highest energy X-rays originate from a small region on the axis. The so-called shadow technique shows that the electron beam is perpendicular to the anode surface. Polar diagrams of medium and high-energy X-rays agree with the bremsstrahlung emission from a relativistic electron beam, the current of which is several 100 A.

  16. Photon emission from quark-gluon plasma out of equilibrium

    Science.gov (United States)

    Hauksson, Sigtryggur; Jeon, Sangyong; Gale, Charles

    2018-01-01

    The photon emission from a nonequilibrium quark-gluon plasma is analyzed. We derive an integral equation that describes photon production through quark-antiquark annihilation and quark bremsstrahlung. It includes coherence between different scattering sites, also known as the Landau-Pomeranchuk-Migdal effect. These leading-order processes are studied for the first time together in an out-of-equilibrium field theoretical treatment that enables the inclusion of viscous corrections to the calculation of electromagnetic emission rates. In the special case of an isotropic, viscous, plasma the integral equation only depends on three constants, which capture the nonequilibrium nature of the medium.

  17. An exact limit of the Aharony-Bergman-Jafferis-Maldacena theory

    Science.gov (United States)

    Bianchi, Marco S.; Leoni, Matias

    2016-08-01

    We study planar Aharony-Bergman-Jafferis-Maldacena (ABJM) theory in a limit where one coupling is negligible compared to the other. We provide a recipe for exactly solving the expectation value of bosonic Bogomol'nyi-Prasad-Sommerfield (BPS) Wilson loops on arbitrary smooth contours, or the leading divergence for cusped ones, using results from localization. As an application, we compute the exact (generalized) cusp anomalous dimension and Bremsstrahlung function and use it to determine the interpolating h -function. We finally prove a conjecture on the exact form of the dilatation operator in a closed sector, hinting at the integrability of this limit.

  18. Optical conductivity of warm dense matter in wide frequency range within quantum statistical and kinetic approach

    CERN Document Server

    Veysman, M; Winkel, M; Reinholz, H

    2016-01-01

    Fundamental properties of warm dense matter are described by the dielectric function, which gives access to the frequency-dependent electrical conductivity, absorption, emission and scattering of radiation, charged particles stopping and further macroscopic properties. Different approaches to the dielectric function and the related dynamical collision frequency are compared in a wide frequency range. The high-frequency limit describing inverse bremsstrahlung and the low-frequency limit of the dc conductivity are considered. Sum rules and Kramers-Kronig relation are checked for the generalized linear response theory and the standard approach following kinetic theory. The results are discussed in application to aluminum, xenon and argon plasmas.

  19. Calculated and measured dose distribution in electron and X-ray irradiated water phantom

    CERN Document Server

    Ziaie, F; Bulka, S; Afarideh, H; Hadji-Saeid, S M

    2002-01-01

    The Bremsstrahlung yields produced by incident electrons on a tantalum converter have been calculated by using a Monte-Carlo computer code. The tantalum thickness as an X-ray converter was optimized for 2, 2.5, 5, 7.5, and 10 MeV electron beams. The dose distribution in scanning and conveyor direction for both 2 MeV electron and X-ray converted from 2 MeV electron beam have been calculated and compared with experimental results. The economical aspects of low energy electron conversion were discussed as well.

  20. Analyses of electron runaway in front of the negative streamer channel

    DEFF Research Database (Denmark)

    Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

    2017-01-01

    , which allows the electric field to reach magnitudes, required for a generation of significant RE fluxes and associated bremsstrahlung, when the ionization wave propagates in a narrow, ionized channel created by a previous streamer. Under such conditions we compute the production rate of REs per unit......-emitting ionization wave independent of the initial electron concentration. Thus, the streamer coronas of the leaders are probable sources of REs producing the observed high-energy radiation. To prove these predictions, new simulations are planned, which would show explicitly that the pre-ionization in front...... of the channel via REs will lead to the ionization wave propagation self-consistent with REs generation....

  1. Heavy ion dynamics and auroral arc formation in the Jovian magnetosphere

    Science.gov (United States)

    Barbosa, D. D.

    1992-01-01

    This paper gives a brief review of some of the current controversial issues surrounding the Jovian aurora. In particular, the manner of its excitation be it that of electron or heavy ion precipitation is examined critically in the context of proposed models for magnetospheric dynamics, particle energization, and auroral energy input. A model for the X-ray aurora based on bremsstrahlung by a primary electron beam and its ionization secondaries is high-lighted and the connection to the outward magnetospheric transport of heavy ion plasma from the satellite Io is made.

  2. Targets and Secondary Beam Extraction

    Science.gov (United States)

    Noah, Etam

    2014-02-01

    Several applications make use of secondary beams of particles generated by the interaction of a primary beam of particles with a target. Spallation neutrons, bremsstrahlung photon-produced neutrons, radioactive ions and neutrinos are available to users at state-of-the-art facilities worldwide. Plans for even higher secondary beam intensities place severe constraints on the design of targets. This article reports on the main targetry challenges and highlights a variety of solutions for targetry and secondary beam extraction. Issues related to target station layout, instrumentation at the beam-target interface, safety and radioprotection are also discussed.

  3. Measurement of angular distribution of neutron flux for the 6 MeV race-track microtron based pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Patil, B.J., E-mail: bjp@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India); Chavan, S.T.; Pethe, S.N.; Krishnan, R. [SAMEER, IIT Powai Campus, Mumbai 400 076 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India)

    2010-09-15

    The 6 MeV race track microtron based pulsed neutron source has been designed specifically for the elemental analysis of short lived activation products, where the low neutron flux requirement is desirable. Electrons impinges on a e-{gamma} target to generate bremsstrahlung radiations, which further produces neutrons by photonuclear reaction in {gamma}-n target. The optimisation of these targets along with their spectra were estimated using FLUKA code. The measurement of neutron flux was carried out by activation of vanadium at different scattering angles. Angular distribution of neutron flux indicates that the flux decreases with increase in the angle and are in good agreement with the FLUKA simulation.

  4. Soft X-ray production by photon scattering in pulsating binary neutron star sources

    Science.gov (United States)

    Bussard, R. W.; Meszaros, P.; Alexander, S.

    1985-01-01

    A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column.

  5. Dipole strength distributions from HIGS Experiments

    Directory of Open Access Journals (Sweden)

    Werner V.

    2015-01-01

    76Ge and 76Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesis

  6. Scalar QED, NLO and PHOTOS Monte Carlo

    OpenAIRE

    Nanava, G.; Was, Z.

    2006-01-01

    Recently, QED bremsstrahlung in $B$-meson decays into pair of scalars (\\pi's and/or K's) is of interest. If experimental acceptance must be taken into account, PHOTOS Monte Carlo is often used in experimental simulations. We will use scalar QED to benchmark PHOTOS, even though this theory is of limited use for complex objects. We present the analytical form of the kernel used in the older versions of PHOTOS, and the new, exact (scalar QED) one. Matrix element and phase-space Jacobians are sep...

  7. High energy high intensity coherent photon beam for the SSC

    Energy Technology Data Exchange (ETDEWEB)

    Tannenbaum, M.J.

    1984-01-01

    What is proposed for the 20 TeV protons hitting a fixed target is to make a tertiary electron beam similar to that which is the basis of the tagged photon beam at Fermilab. Briefly, a zero degree neutral beam is formed by sweeping out the primary proton beam and any secondary charged particles. Then the photons, from the decay of ..pi../sup 0/ in the neutral beam, are converted to e/sup +/e/sup -/ pairs in a lead converter and a high quality electron beam is formed. This beam is brought to the target area where it is converted to a photon beam by Bremsstrahlung in a radiator.

  8. Entwicklung einer aktiven 238Uran(VI)-fluorid-Detektor-Kammer für Präzisionsexperimente in der photoneninduzierten Spaltung am S-DALINAC

    OpenAIRE

    Eckardt, Christian

    2013-01-01

    Der am S-DALINAC installierte Injektor spinpolarisierter Elektronen SPIN ermöglicht den Einsatz zirkular polarisierter Bremsstrahlung mit einem hohen Polarisationsgrad in der Nähe der Endpunktsenergie für die Suche nach paritätsverletzenden Effekten in der Vorwärts-Rückwärts-Asymmetrie des leichten und schweren Spaltfragmentes der photoneninduzierten Spaltung an 238U. Zur Steigerung der Luminosität wurde im Rahmen dieser Arbeit eine aktive 238Uran(VI)-fluorid-Detektor-Kammer nach dem Prin...

  9. First Results from The GlueX Experiment

    CERN Document Server

    Ghoul, H Al; Barbosa, F; Barnes, A; Beattie, T D; Bennett, D W; Berdnikov, V V; Black, T; Boeglin, W; Brooks, W K; Cannon, B; Chernyshov, O; Chudakov, E; Crede, V; Dalton, M M; Deur, A; Dobbs, S; Dolgolenko, A; Dugger, M; Egiyan, H; Eugenio, P; Foda, A M; Frye, J; Furletov, S; Gan, L; Gasparian, A; Gerasimov, A; Gevorgyan, N; Goryachev, V S; Guegan, B; Guo, L; Hakobyan, H; Hakobyan2, H; Hardin, J; Huber, G M; Ireland, D; Ito, M M; Jarvis, N S; Jones, R T; Kakoyan, V; Kamel, M; Klein, F J; Kourkoumeli, C; Kuleshov, S; Lara, M; Larin, I; Lawrence, D; Leckey, J; Levine, W I; Livingston, K; Lolos, G J; Mack, D; Mattione, P T; Matveev, V; McCaughan, M; McGinley, W; McIntyre, J; Mendez, R; Meyer, C A; Miskimen, R; Mitchell, R E; Mokaya, F; Moriya, K; Nigmatkulov, G; Ochoa, N; Ostrovidov, A I; Papandreou, Z; Pedroni, R; Pennington, M; Pentchev, L; Ponosov, A; Pooser, E; Pratt, B; Qiang, Y; Reinhold, J; Ritchie, B G; Robison, L; Romanov, D; Salgado, C; Schumacher, R A; Semenov, A Yu; Semenova, I A; Senderovich, I; Seth, K K; Shepherd, M R; Smith, E S; Sober, D I; Somov, A; Somov, S; Soto, O; Sparks, N; Staib, M J; Stevens, J R; Subedi, A; Tarasov, V; Taylor, S; Tolstukhin, I; Tomaradze, A; Toro, A; Tsaris, A; Vasileiadis, G; Vega, I; Voulgaris, G; Walford, N K; Whitlatch, T; Williams, M; Wolin, E; Xiao, T; Zarling, J; Zihlmann, B

    2015-01-01

    The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic and liquid hydrogen targets, and much of the detector has been commissioned. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed, including exclusive production of $\\pi^{0}$, $\\eta$ and $\\omega$ mesons. Linearly-polarized photons were successfully produced through coherent bremsstrahlung and polarization transfer to the $\\rho$ has been observed.

  10. Bibliography of Photon Total Cross Section (Attenuation Coefficient) Measurements

    CERN Document Server

    Hubbell, J H

    A bibliography is presented of papers reporting absolute measurements of photon (XUV, x-ray, gamma-ray, bremsstrahlung) total interaction cross sections or attenuation coefficients for the elements and some compounds. The energy range covered is from 10 eV to above 10 GeV. These papers are part of the reference collection of the National Institute of Standards and Technology Photon and Charged Particle Data Center. They cover the period from 1907 through 1995. Included with each reference are annotations specifying the energy range covered and the substances studied. This updated bibliography now includes 580 non-duplicative references to available measured data, plus 42 references to critical evaluatio

  11. Laser-produced plasma (LPP) x-ray source with BaF2 and rare-earth targets for application in dual-energy subtraction angiography (DESA)

    Science.gov (United States)

    Krol, Andrzej; Kieffer, Jean-Claude; Jiang, Zhiming; Yu, Jianfan; Chamberlain, Charles C.; Bassano, Daniel A.; Gallant, Pascal

    1999-05-01

    A laser produced plasma (LPP) x-ray source utilizing ultra- fast laser was investigated in the context of its utility for dual energy subtraction angiography. Experiments were performed with a Table Top Terawatt (TTT) laser using BaF2 and rare-earth metal targets including La, Ce, Nd and Gd. The laser was operated in a single-pulse or in a dual pulse mode with surface power density in the 1018 - 1019 Wcm-2 range with pulse duration of 150 or 450 fs. Infrared and/or green beams were utilized. Hot electrons' temperature was in the 35 - 50 keV range. The obtained LPP x- ray spectra were comprised of a continuous bremsstrahlung component as well as discrete characteristic lines. The bremsstrahlung extended to high energies with no evident cutoff energy below 100 keV. Its shape was best described by exp(-E/kTe), where Te is the hot electron temperature. The overall efficiency was equal to approximately 9 X 10-4 for 450 fs pulse and approximately 6 X 10-4 for 150 fs pulses. The x-ray focal spot size was in the range 13 to 50 microns. We have found that the LPP x- ray source with BaF2 and rare-earth targets provide x-ray spectra that might be suitable for DESA.

  12. Study of the Dependence of Direct Soft Photon Production on the Jet Characteristics in Hadronic $Z^0$ Decays

    CERN Document Server

    Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, U; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W-D; Arnoud, Y; Ask, S; Asman, B; Augustin, J E; Augustinus, A; Baillon, P; Ballestrero, A; Bambade, P; Barbier, R; Bardin, D; Barker, G J; Baroncelli, A; Battaglia, M; Baubillier, M; Becks, K-H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N; Benvenuti, A; Berat, C; Berggren, M; Bertrand, D; Besancon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Bruckman, P; Brunet, J M; Buschbeck, B; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F; Chapkin, M; Charpentier, Ph; Checchia, P; Chierici, R; Chliapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crennell, D; Cuevas, J; D'Hondt, J; da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; De Boer, W; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; de Paula, L; Di Ciaccio, L; Di Simone, A; Doroba, K; Drees, J; Eigen, G; Ekelof, T; Ellert, M; Elsing, M; Espirito Santo, M C; Fanourakis, G; Fassouliotis, D; Feindt, M; Fernandez, J; Ferrer, A; Ferro, F; Flagmeyer, U; Foeth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J; Gandelman, M; Garcia, C; Gavillet, Ph; Gazis, E; Gokieli, R; Golob, B; Gomez-Ceballos, G; Goncalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Hoffman, J; Holmgren, S-O; Holt, P J; Houlden, M A; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E; Kernel, G; Kersevan, B P; Kerzel, U; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kouznetsov, O; Krumstein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; Lopez, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Marechal, B; Margoni, M; Marin, J-C; Mariotti, C; Markou, A; Martinez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; Mc Nulty, R; Meroni, C; Migliore, E; Mitaroff, W; Mjoernmark, U; Moa, T; Moch, M; Moenig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Mueller, U; Muenich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, G; Myklebust, T; Nassiakou, M; Navarria, F; Nawrocki, K; Nemecek, S; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V; Olshevski, A; Onofre, A; Orava, R; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, Th D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Pozdniakov, V; Pukhaeva, N; Pullia, A; Radojicic, D; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P; Richard, F; Ridky, J; Rivero, M; Rodriguez, D; Romero, A; Ronchese, P; Roudeau, P; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovsky, A; Salmi, L; Salt, J; Sander, C; Savoy-Navarro, A; Schwickerath, U; Sekulin, R; Siebel, M; Sisakian, A; Smadja, G; Smirnova, O; Sokolov, A; Sopczak, A; Sosnowski, R; Spassov, T; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli, T; Tegenfeldt, F; Timmermans, J; Tkatchev, L; Tobin, M; Todorovova, S; Tome, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M-L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; Van Dam, P; Van Eldik, J; van Remortel, N; Van Vulpen, I; Vegni, G; Veloso, F; Venus, W; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O; Zalewska, A; Zalewski, P; Zavrtanik, D; Zhuravlov, V; Zimin, N I; Zintchenko, A; Zupan, M

    2010-01-01

    An analysis of the direct soft photon production rate as a function of the parent jet characteristics is presented, based on hadronic events collected by the DELPHI experiment at LEP1. The dependences of the photon rates on the jet kinematic characteristics (momentum, mass, etc.) and on the jet charged, neutral and total hadron multiplicities are reported. Up to a scale factor of about four, which characterizes the overall value of the soft photon excess, a similarity of the observed soft photon behaviour to that of the inner hadronic bremsstrahlung predictions is found for the momentum, mass, and jet charged multiplicity dependences. However for the dependence of the soft photon rate on the jet neutral and total hadron multiplicities a prominent difference is found for the observed soft photon signal as compared to the expected bremsstrahlung from final state hadrons. The observed linear increase of the soft photon production rate with the jet total hadron multiplicity and its strong dependence on the jet ne...

  13. Evidence for an excess of soft photons in hadronic decays of $Z^{0}$

    CERN Document Server

    Abdallah, J; Adam, W; Adzic, P; Albrecht, T; Alderweireld, T; Alemany-Fernandez, R; Allmendinger, T; Allport, P P; Amaldi, Ugo; Amapane, N; Amato, S; Anashkin, E; Andreazza, A; Andringa, S; Anjos, N; Antilogus, P; Apel, W D; Arnoud, Y; Ask, S; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Ballestrero, A; Bambade, P; Barbier, R; Bardin, D; Barker, G J; Baroncelli, A; Battaglia, M; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Ben-Haim, E; Benekos, N; Benvenuti, A C; Bérat, C; Berggren, M; Berntzon, L; Bertrand, D; Besançon, M; Besson, N; Bloch, D; Blom, M; Bluj, M; Bonesini, M; Boonekamp, M; Booth, P S L; Borisov, G; Botner, O; Bouquet, B; Bowcock, T J V; Boyko, I; Bracko, M; Brenner, R; Brodet, E; Brückman, P; Brunet, J M; Buschbeck, Brigitte; Buschmann, P; Calvi, M; Camporesi, T; Canale, V; Carena, F; Castro, N; Cavallo, F; Chapkin, M; Charpentier, P; Checchia, P; Chierici, R; Shlyapnikov, P; Chudoba, J; Chung, S U; Cieslik, K; Collins, P; Contri, R; Cosme, G; Cossutti, F; Costa, M J; Crennell, D J; Cuevas-Maestro, J; D'Hondt, J; Dalmau, J; Da Silva, T; Da Silva, W; Della Ricca, G; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Maria, N; De Min, A; De Paula, L; Di Ciaccio, L; Di Simone, A; Doroba, K; Drees, J; Eigen, G; Ekelöf, T J C; Ellert, M; Elsing, M; Espirito-Santo, M C; Fanourakis, G K; Fassouliotis, D; Feindt, M; Fernández, J; Ferrer, A; Ferro, F; Flagmeyer, U; Föth, H; Fokitis, E; Fulda-Quenzer, F; Fuster, J; Gandelman, M; García, C; Gavillet, P; Gazis, E; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; Graziani, E; Grosdidier, G; Grzelak, K; Guy, J; Haag, C; Hallgren, A; Hamacher, K; Hamilton, K; Haug, S; Hauler, F; Hedberg, V; Hennecke, M; Herr, H; Hoffman, J; Holmgren, S O; Holt, P J; Houlden, M A; Hultqvist, K; Jackson, J N; Jarlskog, G; Jarry, P; Jeans, D; Johansson, E K; Johansson, P D; Jonsson, P; Joram, C; Jungermann, L; Kapusta, F; Katsanevas, S; Katsoufis, E; Kernel, G; Kersevan, B P; Kerzel, U; King, B T; Kjaer, N J; Kluit, P; Kokkinias, P; Kourkoumelis, C; Kuznetsov, O; Krumshtein, Z; Kucharczyk, M; Lamsa, J; Leder, G; Ledroit, F; Leinonen, L; Leitner, R; Lemonne, J; Lepeltier, V; Lesiak, T; Liebig, W; Liko, D; Lipniacka, A; Lopes, J H; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J; Malek, A; Maltezos, S; Mandl, F; Marco, J; Marco, R; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Masik, J; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Mazzucato, F; Mazzucato, M; McNulty, R; Meroni, C; Migliore, E; Mitaroff, W A; Mjörnmark, U; Moa, T; Moch, M; Mönig, K; Monge, R; Montenegro, J; Moraes, D; Moreno, S; Morettini, P; Müller, U; Münich, K; Mulders, M; Mundim, L; Murray, W; Muryn, B; Myatt, G; Myklebust, T; Nassiakou, M; Navarria, Francesco Luigi; Nawrocki, K; Nicolaidou, R; Nikolenko, M; Oblakowska-Mucha, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, R; Österberg, K; Ouraou, A; Oyanguren, A; Paganoni, M; Paiano, S; Palacios, J P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Peralta, L; Perepelitsa, V F; Perrotta, A; Petrolini, A; Piedra, J; Pieri, L; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Poireau, V; Pol, M E; Polok, G; Pozdnyakov, V; Pukhaeva, N; Pullia, A; Rames, J; Read, A; Rebecchi, P; Rehn, J; Reid, D; Reinhardt, R; Renton, P B; Richard, F; Rídky, J; Rivero, M; Rodríguez, D; Romero, A; Ronchese, P; Roudeau, P; Rovelli, T; Ruhlmann-Kleider, V; Ryabtchikov, D; Sadovskii, A; Salmi, L; Salt, J; Sander, C; Savoy-Navarro, A; Schwickerath, U; Segar, A; Sekulin, R L; Siebel, M; Sisakian, A; Smadja, G; Smirnova, O; Sokolov, A; Sopczak, A; Sosnowski, R; Spassoff, Tz; Stanitzki, M; Stocchi, A; Strauss, J; Stugu, B; Szczekowski, M; Szeptycka, M; Szumlak, T; Tabarelli de Fatis, T; Taffard, A C; Tegenfeldt, F; Timmermans, J; Tkatchev, L G; Tobin, M; Todorovova, S; Tomé, B; Tonazzo, A; Tortosa, P; Travnicek, P; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Turluer, M L; Tyapkin, I A; Tyapkin, P; Tzamarias, S; Uvarov, V; Valenti, G; van Dam, P; Van Eldik, J; Van Remortel, N; Van Vulpen, I; Vegni, G; Veloso, F; Venus, W; Verdier, P; Verzi, V; Vilanova, D; Vitale, L; Vrba, V; Wahlen, H; Washbrook, A J; Weiser, C; Wicke, D; Wickens, J; Wilkinson, G; Winter, M; Witek, M; Yushchenko, O P; Zalewska-Bak, A; Zalewski, P; Zavrtanik, D; Zhuravlov, V; Zimin, N I; Zintchenko, A; Zupan, M

    2006-01-01

    Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qqbar disintegrations of the Z^0 were studied in the kinematic range 0.2 < E_gamma < 1 GeV and transverse momentum with respect to the closest jet direction p_T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10^{-3} gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) x 10^{-3} gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.

  14. Plasma instability control toward high fluence, high energy x-ray continuum source

    Science.gov (United States)

    Poole, Patrick; Kirkwood, Robert; Wilks, Scott; Blue, Brent

    2017-10-01

    X-ray source development at Omega and NIF seeks to produce powerful radiation with high conversion efficiency for material effects studies in extreme fluence environments. While current K-shell emission sources can achieve tens of kJ on NIF up to 22 keV, the conversion efficiency drops rapidly for higher Z K-alpha energies. Pulsed power devices are efficient generators of MeV bremsstrahlung x-rays but are unable to produce lower energy photons in isolation, and so a capability gap exists for high fluence x-rays in the 30 - 100 keV range. A continuum source under development utilizes instabilities like Stimulated Raman Scattering (SRS) to generate plasma waves that accelerate electrons into high-Z converter walls. Optimizing instabilities using existing knowledge on their elimination will allow sufficiently hot and high yield electron distributions to create a superior bremsstrahlung x-ray source. An Omega experiment has been performed to investigate the optimization of SRS and high energy x-rays using Au hohlraums with parylene inner lining and foam fills, producing 10× greater x-ray yield at 50 keV than conventional direct drive experiments on the facility. Experiment and simulation details on this campaign will be presented. This work was performed under the auspices of the US DoE by LLNL under Contract No. DE-AC52-07NA27344.

  15. Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

    CERN Multimedia

    2002-01-01

    The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

  16. Study of the dependence of direct soft photon production on the jet characteristics in hadronic Z 0 decays

    Science.gov (United States)

    Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P. P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J. E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G. J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.-H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P. S. L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T. J. V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J. M.; Buschbeck, B.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S. U.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M. J.; Crennell, D.; Cuevas, J.; D'Hondt, J.; da Silva, T.; da Silva, W.; Della Ricca, G.; de Angelis, A.; de Boer, W.; de Clercq, C.; de Lotto, B.; de Maria, N.; de Min, A.; de Paula, L.; di Ciaccio, L.; di Simone, A.; Doroba, K.; Drees, J.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M. C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Hoffman, J.; Holmgren, S.-O.; Holt, P. J.; Houlden, M. A.; Jackson, J. N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E. K.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B. P.; Kerzel, U.; King, B. T.; Kjaer, N. J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J. H.; Lopez, J. M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Mc Nulty, R.; Meroni, C.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nemecek, S.; Nicolaidou, R.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J. P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M. E.; Polok, G.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Radojicic, D.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Sander, C.; Savoy-Navarro, A.; Schwickerath, U.; Sekulin, R.; Siebel, M.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Tegenfeldt, F.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.-L.; Tyapkin, I. A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; van Dam, P.; van Eldik, J.; van Remortel, N.; van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A. J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimin, N. I.; Zintchenko, A.; Zupan, M.; DELPHI Collaboration

    2010-06-01

    An analysis of the direct soft photon production rate as a function of the parent jet characteristics is presented, based on hadronic events collected by the DELPHI experiment at LEP1. The dependences of the photon rates on the jet kinematic characteristics (momentum, mass, etc.) and on the jet charged, neutral and total hadron multiplicities are reported. Up to a scale factor of about four, which characterizes the overall value of the soft photon excess, a similarity of the observed soft photon behavior to that of the inner hadronic bremsstrahlung predictions is found for the momentum, mass, and jet charged multiplicity dependences. However for the dependence of the soft photon rate on the jet neutral and total hadron multiplicities a prominent difference is found for the observed soft photon signal as compared to the expected bremsstrahlung from final state hadrons. The observed linear increase of the soft photon production rate with the jet total hadron multiplicity and its strong dependence on the jet neutral multiplicity suggest that the rate is proportional to the number of quark pairs produced in the fragmentation process, with the neutral pairs being more effectively radiating than the charged ones.

  17. Anisotropy and linear polarization of radiative processes in energetic ion-atom collisions; Untersuchung zur Anisotropie und linearen Polarisation radiativer Prozesse in energiereichen Ion-Atom-Stoessen

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Guenter

    2010-06-16

    In the present thesis the linear polarization of radiation emitted in energetic ion-atom collisions at the ESR storage ring was measured by applying a novel type of position, timing and energy sensitive X-ray detector as a Compton polarimeter. In contrast to previous measurements, that mainly concentrate on studies of the spectral and angular distribution, the new detectors allowed the first polarization study of the Ly-{alpha}{sub 1} radiation (2p{sub 3/2}{yields}1s{sub 1/2}) in U{sup 91+}. Owing to the high precision of the polarimeters applied here, the experimental results indicate a significant depolarization of the Ly-{alpha}{sub 1} radiation caused by the interference of the E1 and M2 transition branches. Moreover, the current investigation shows that measurements of the linear polarization in combination with angular distribution studies provide a model-independent probe for the ratio of the E1 and M2 transition amplitudes and, consequently, of the corresponding transition probabilities. In addition, a first measurement of the linear polarization as well as an angular distribution study of the electron-nucleus Bremsstrahlung arising from ion-atom collisions was performed. The experimental results obtained were compared to exact relativistic calculations and, in case of the Bremsstrahlung, to a semirelativistic treatment. In general, good agreement was found between theoretical predictions and experimental findings. (orig.)

  18. A Concept for Measuring Electron Distribution Functions Using Collective Thomson Scattering

    Science.gov (United States)

    Milder, A. L.; Froula, D. H.

    2017-10-01

    A.B. Langdon proposed that stable non-Maxwellian distribution functions are realized in coronal inertial confinement fusion plasmas via inverse bremsstrahlung heating. For Zvosc2 Zvosc2 vth2 > 1 , vth2 > 1 , the inverse bremsstrahlung heating rate is sufficiently fast to compete with electron-electron collisions. This process preferentially heats the subthermal electrons leading to super-Gaussian distribution functions. A method to identify the super-Gaussian order of the distribution functions in these plasmas using collective Thomson scattering will be proposed. By measuring the collective Thomson spectra over a range of angles the density, temperature and super-Gaussian order can be determined. This is accomplished by fitting non-Maxwellian distribution data with a super-Gaussian model; in order to match the density and electron temperature to within 10%, the super-Gaussian order must be varied. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  19. Particle energy cascade in the intergalactic medium

    Science.gov (United States)

    Valdés, M.; Evoli, C.; Ferrara, A.

    2010-05-01

    We study the development of high-energy (Ein new code MEDEA (Monte Carlo Energy Deposition Analysis) which includes Bremsstrahlung and inverse Compton (IC) processes, along with H/He collisional ionizations and excitations, and electron-electron collisions. The cascade energy partition into heating, excitations and ionizations depends primarily not only on the IGM ionized fraction, xe, but also on redshift, z, due to IC on cosmic microwave background (CMB) photons. While Bremsstrahlung is unimportant under most conditions, IC becomes largely dominant at energies Ein >= 1 MeV. The main effect of IC at injection energies Ein = 1 GeV CMB photons are preferentially upscattered within the X-ray spectrum (hν > 104 eV) and can free stream to the observer. Complete tables of the fractional energy depositions as a function of redshift, Ein and ionized fraction are given. Our results can be used in many astrophysical contexts, with an obvious application related to the study of decaying/annihilating dark matter (DM) candidates in the high-z Universe.

  20. Pulse Power Compression by Cutting a Dense Z-Pinch with a Laser Beam

    Science.gov (United States)

    Winterberg, F.

    1999-07-01

    A thin cut made through a z-pinch by an intense laser beam can become a magnetically insulated diode crossed by an intense ion beam. For larger cuts, the gap is crossed by an intense relativistic electron beam, stopped by magnetic bremsstrahlung resulting in a pointlike intense x-ray source. In either case, the impedance of the pinch discharge is increased, with the power delivered rising in the same pro-portion. A magnetically insulated cut is advantageous for three reasons: First, with the ion current com-parable to the Alfvèn ion current, the pinch instabilities are reduced. Second, with the energy deposit-ed into fast ions, a non-Maxwellian velocity distribution is established increasing value for nuclear fusion reactions taking place in the pinch discharge. Third, in a high density z-pinch plasma, the intense ion beam can launch a thermonuclear detonation wave propagating along the pinch discharge channel. For larger cuts the soft x-rays produced by magnetic bremsstrahlung can be used to drive a thermonuclear hohlraum target. Finally, the proposed pulse power compression scheme permits to use a cheap low power d.c. source charging a magnetic storage coil delivering the magnetically stored energy to the pinch discharge load by an exploding wire opening switch.

  1. Modelling Energy Loss Mechanisms and a Determination of the Electron Energy Scale for the CDF Run II W Mass Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Riddick, Thomas [Univ. College London, Bloomsbury (United Kingdom)

    2012-06-15

    The calibration of the calorimeter energy scale is vital to measuring the mass of the W boson at CDF Run II. For the second measurement of the W boson mass at CDF Run II, two independent simulations were developed. This thesis presents a detailed description of the modification and validation of Bremsstrahlung and pair production modelling in one of these simulations, UCL Fast Simulation, comparing to both geant4 and real data where appropriate. The total systematic uncertainty on the measurement of the W boson mass in the W → eve channel from residual inaccuracies in Bremsstrahlung modelling is estimated as 6.2 ±3.2 MeV/c2 and the total systematic uncertainty from residual inaccuracies in pair production modelling is estimated as 2.8± 2.7 MeV=c2. Two independent methods are used to calibrate the calorimeter energy scale in UCL Fast Simulation; the results of these two methods are compared to produce a measurement of the Z boson mass as a cross-check on the accuracy of the simulation.

  2. Geant4 simulation of gamma conversion to muon pair for dark matter searches

    CERN Document Server

    Sokolov, Anton

    2017-01-01

    There is a direct evidence from different astronomical observations and CMB spectrum that 26% of the visible part of the Universe consists of so-called dark matter. There are many models explaining the phenomenon of dark matter, however none of them has been confirmed experimentally. It justifies the further searches for the dark matter that involve more and more various experiments, such as, for instance, SHiP experiment [1] at CERN or LDMX project [2] at SLAC. LDMX (Light Dark Matter eXperiment) is an electron fixedtarget missing momentum search for light dark matter. The main process that LDMX looks for is dark bremsstrahlung (i.e. emitting a light dark matter particle) by the several GeV electrons scattered off the target. This process is contaminated by the background of ordinary bremsstrahlung, that consists of many different processes which can be accounted for and vetoed by various counters. The experiment designs are studied with the Geant4 toolkit. Recently, one of the important background pro...

  3. 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.

  4. 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.

  5. Development of backlighting sources for a Compton radiography diagnostic of inertial confinement fusion targets (invited).

    Science.gov (United States)

    Tommasini, R; MacPhee, A; Hey, D; Ma, T; Chen, C; Izumi, N; Unites, W; MacKinnon, A; Hatchett, S P; Remington, B A; Park, H S; Springer, P; Koch, J A; Landen, O L; Seely, John; Holland, Glenn; Hudson, Larry

    2008-10-01

    We present scaled demonstrations of backlighter sources, emitting bremsstrahlung x rays with photon energies above 75 keV, that we will use to record x-ray Compton radiographic snapshots of cold dense DT fuel in inertial confinement fusion implosions at the National Ignition Facility (NIF). In experiments performed at the Titan laser facility at Lawrence Livermore National Laboratory, we measured the source size and the bremsstrahlung spectrum as a function of laser intensity and pulse length from solid targets irradiated at 2x10(17)-5x10(18) W/cm(2) using 2-40 ps pulses. Using Au planar foils we achieved source sizes down to 5.5 microm and conversion efficiencies of about 1x10(-13) J/J into x-ray photons with energies in the 75-100 keV spectral range. We can now use these results to design NIF backlighter targets and shielding and to predict Compton radiography performance as a function of the NIF implosion yield and associated background.

  6. Gamma Putty dosimetric studies in electron beam

    Directory of Open Access Journals (Sweden)

    Aime M Gloi

    2016-01-01

    Full Text Available Traditionally, lead has been used for field shaping in megavoltage electron beams in radiation therapy. In this study, we analyze the dosimetric parameters of a nontoxic, high atomic number (Z = 83, bismuth-loaded material called Gamma Putty that is malleable and can be easily molded to any desired shape. First, we placed an ionization chamber at different depths in a solid water phantom under a Gamma Putty shield of thickness (t = 0, 3, 5, 10, 15, 20, and 25 mm, respectively and measured the ionizing radiation on the central axis (CAX for electron beam ranging in energies from 6 to 20 MeV. Next, we investigated the relationship between the relative ionization (RI measured at a fixed depth for several Gamma Putty shield at different cutout diameters ranging from 2 to 5 cm for various beam energies and derived an exponential fitting equation for clinical purposes. The dose profiles along the CAX show that bremsstrahlung dominates for Gamma Putty thickness >15 mm. For high-energy beams (12-20 MeV and all Gamma Putty thicknesses up to 25 mm, RI below 5% could not be achieved due to the strong bremsstrahlung component. However, Gamma Putty is a very suitable material for reducing the transmission factor below 5% and protecting underlying normal tissues for low-energy electron beams (6-9 MeV.

  7. E1 and M1 strength functions at low energy

    Science.gov (United States)

    Schwengner, Ronald; Massarczyk, Ralph; Bemmerer, Daniel; Beyer, Roland; Junghans, Arnd R.; Kögler, Toni; Rusev, Gencho; Tonchev, Anton P.; Tornow, Werner; Wagner, Andreas

    2017-09-01

    We report photon-scattering experiments using bremsstrahlung at the γELBE facility of Helmholtz-Zentrum Dresden-Rossendorf and using quasi-monoenergetic, polarized γ beams at the HIγS facility of the Triangle Universities Nuclear Laboratory in Durham. To deduce the photoabsorption cross sections at high excitation energy and high level density, unresolved strength in the quasicontinuum of nuclear states has been taken into account. In the analysis of the spectra measured by using bremsstrahlung at γELBE, we perform simulations of statistical γ-ray cascades using the code γDEX to estimate intensities of inelastic transitions to low-lying excited states. Simulated average branching ratios are compared with model-independent branching ratios obtained from spectra measured by using monoenergetic γ beams at HIγS. E1 strength in the energy region of the pygmy dipole resonance is discussed in nuclei around mass 90 and in xenon isotopes. M1 strength in the region of the spin-flip resonance is also considered for xenon isotopes. The dipole strength function of 74Ge deduced from γELBE experiments is compared with the one obtained from experiments at the Oslo Cyclotron Laboratory. The low-energy upbend seen in the Oslo data is interpreted as M1 strength on the basis of shell-model calculations.

  8. Ray-Based Calculations with DEPLETE of Laser Backscatter in ICF Targets

    Energy Technology Data Exchange (ETDEWEB)

    Strozzi, D J; Williams, E; Hinkel, D; Froula, D; London, R; Callahan, D

    2008-05-19

    A steady-state model for Brillouin and Raman backscatter along a laser ray path is presented. The daughter plasma waves are treated in the strong damping limit, and have amplitudes given by the (linear) kinetic response to the ponderomotive drive. Pump depletion, inverse-bremsstrahlung damping, bremsstrahlung emission, Thomson scattering off density fluctuations, and whole-beam focusing are included. The numerical code Deplete, which implements this model, is described. The model is compared with traditional linear gain calculations, as well as 'plane-wave' simulations with the paraxial propagation code pF3D. Comparisons with Brillouin-scattering experiments at the Omega Laser Facility show that laser speckles greatly enhance the reflectivity over the Deplete results. An approximate upper bound on this enhancement is given by doubling the Deplete coupling coefficient. Analysis with Deplete of an ignition design for the National Ignition Facility (NIF), with a peak radiation temperature of 285 eV, shows encouragingly low reflectivity. Doubling the coupling to bracket speckle effects suggests a less optimistic picture. Re-absorption of Raman light is seen to be significant in this design.

  9. Ray-Based Calculations of Backscatter in Laser Fusion Targets

    Energy Technology Data Exchange (ETDEWEB)

    Strozzi, D J; Williams, E A; Hinkel, D E; Froula, D H; London, R A; Callahan, D A

    2008-02-26

    A steady-state model for Brillouin and Raman backscatter along a laser ray path is presented. The daughter plasma waves are treated in the strong damping limit, and have amplitudes given by the (linear) kinetic response to the ponderomotive drive. Pump depletion, inverse-bremsstrahlung damping, bremsstrahlung emission, Thomson scattering off density fluctuations, and whole-beam focusing are included. The numerical code deplete, which implements this model, is described. The model is compared with traditional linear gain calculations, as well as 'plane-wave' simulations with the paraxial propagation code pf3d. Comparisons with Brillouin-scattering experiments at the OMEGA Laser Facility [T. R. Boehly et al., Opt. Commun. 133, p. 495 (1997)] show that laser speckles greatly enhance the reflectivity over the deplete results. An approximate upper bound on this enhancement, motivated by phase conjugation, is given by doubling the deplete coupling coefficient. Analysis with deplete of an ignition design for the National Ignition Facility (NIF) [J. A. Paisner, E. M. Campbell, and W. J. Hogan, Fusion Technol. 26, p. 755 (1994)], with a peak radiation temperature of 285 eV, shows encouragingly low reflectivity. Doubling the coupling to bound the speckle enhancement suggests a less optimistic picture. Re-absorption of Raman light is seen to be significant in this design.

  10. Measurement of the triple gluon vertex from double quark tagged 4-jet events

    CERN Document Server

    Abreu, P; Adye, T; Adzic, P; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andersson, P; Andreazza, A; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbi, M S; Barbiellini, Guido; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Bärring, O; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bizouard, M A; Bloch, D; Blume, M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Colomer, M; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahm, J; D'Almagne, B; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Di Diodato, A; Djannati, A; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Durand, J D; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Fichet, S; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Geryukov, L; Gokieli, R; Golob, B; Gonçalves, P; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Green, C; Grefrath, A; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Knoblauch, D; Kokkinias, P; Konoplyannikov, A K; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Mahon, J R; Maio, A; Malmgren, T G M; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Medbo, J; Meroni, C; Meyer, S; Meyer, W T; Myagkov, A; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Münich, K; Mulders, M; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Nikolenko, M; Niss, P; Nomerotski, A; Normand, Ainsley; Nygren, A; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Ortuno, S; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Paiano, S; Pain, R; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Piotto, E; Podobnik, T; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Roos, L; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sannino, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Serbelloni, L; Shellard, R C; Sheridan, A; Siegrist, P; Silvestre, R; Simonetto, F; Sissakian, A N; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sokolov, A; Solovyanov, O; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stampfer, D; Stanescu, C; Stanic, S; Stapnes, Steinar; Stavitski, I; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chernyaev, E; Tegenfeldt, F; Terranova, F; Thomas, J; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Todorova, S; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; van Apeldoorn, G W; van Dam, P; Van Eldik, J; Van Lysebetten, A; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wlodek, T; Yi, J; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G

    1997-01-01

    The 4-jet events collected by the DELPHI experiment at LEP1 in 1992, 1993 and 1994 are analysed to determine the contribution of the triple-gluon vertex. Two of the four jets are tagged as jets from $b$- or $c$-quarks using lifetime and lepton transverse momentum information. The 4-jet contributions from double-gluon bremsstrahlung, the triple-gluon vertex, and secondary quark-antiquark pair production then yield significantly different two-dimensional distributions in the generalized Nachtmann Reiter angle %$\\Theta^{*}_{NR}$ versus the opening angle of the two secondary jets. These distributions are used to fit $C_A/C_F$, the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung, and $N_C/N_A$, the ratio of the number of quark colours to the number of gluons, giving \\begin{center} $C_A/C_F=2.51 \\pm 0.28$ ~and~ $N_C/N_A=0.38 \\pm 0.10$ \\end{center} in agreement with the values expected from QCD: \\begin{center} $C_A/C_F = 9/4 = 2.25$ ~and~ $N_C/N_A = 3/8 = 0.375$. \\end{center...

  11. SU-F-I-13: Correction Factor Computations for the NIST Ritz Free Air Chamber for Medium-Energy X Rays

    Energy Technology Data Exchange (ETDEWEB)

    Bergstrom, P [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States)

    2016-06-15

    Purpose: The National Institute of Standards and Technology (NIST) uses 3 free-air chambers to establish primary standards for radiation dosimetry at x-ray energies. For medium-energy × rays, the Ritz free-air chamber is the main measurement device. In order to convert the charge or current collected by the chamber to the radiation quantities air kerma or air kerma rate, a number of correction factors specific to the chamber must be applied. Methods: We used the Monte Carlo codes EGSnrc and PENELOPE. Results: Among these correction factors are the diaphragm correction (which accounts for interactions of photons from the x-ray source in the beam-defining diaphragm of the chamber), the scatter correction (which accounts for the effects of photons scattered out of the primary beam), the electron-loss correction (which accounts for electrons that only partially expend their energy in the collection region), the fluorescence correction (which accounts for ionization due to reabsorption ffluorescence photons and the bremsstrahlung correction (which accounts for the reabsorption of bremsstrahlung photons). We have computed monoenergetic corrections for the NIST Ritz chamber for the 1 cm, 3 cm and 7 cm collection plates. Conclusion: We find good agreement with other’s results for the 7 cm plate. The data used to obtain these correction factors will be used to establish air kerma and it’s uncertainty in the standard NIST x-ray beams.

  12. Characteristics of plasma plume in fiber laser welding of aluminum alloy

    Science.gov (United States)

    Gao, Ming; Chen, Cong; Hu, Ming; Guo, Lianbo; Wang, Zemin; Zeng, Xiaoyan

    2015-01-01

    To understand the laser-matter interaction in fiber laser welding of aluminum alloys, the effects of laser power on the characteristics of fiber laser induced plasma plume were studied by emission spectroscopic analysis firstly. The plasma characteristic parameters including electron temperature, electron density, ionization degree, and inverse bremsstrahlung linear absorption coefficient were computed according to the spectral data. It was found that the laser power of 5 kW is a turning point. After the laser power reaches 5 kW, the plume changes from a metal vapor dominated weakly ionized plasma to a strongly ionized plasma. The corresponding phenomena are the dramatic increase of the value of characteristic parameters and the appearance of strong plasma shielding effect. The calculation of effective laser power density demonstrated that the plasma shielding effect is dominated by inverse bremsstrahlung absorption. The finding suggested the plasma shielding effect must be considered in fiber laser welding of aluminum alloys, rather than is ignored as claimed in previous view.

  13. ELECTROMAGNETIC PROCESSES IN STRONG CRYSTALLINE FIELDS

    CERN Document Server

    Uggerhoj, U I; Esberg, J; Knudsen, H; Lund, M; Møller, S P; Sørensen, A H; Thomsen, A H; Uggerhøj, U I; Geissel, H; Scheidenberger, C; Weick, H; Winfield, J; Sona, P; Connell S; Ballestrero, S; Ketel, T; Dizdar, A; Mangiarotti, A

    2009-01-01

    As an addendum to the NA63 proposal cite{Ande05}, we propose to measure 1) the Landau-Pomeranchuk-Migdal (LPM) effect in low-$Z$ targets, 2) Magnetic suppression of incoherent bremsstrahlung resulting from exposure to an external field during the emission event, and 3) the bremsstrahlung emission from relativistic ($gamma=170$), fully stripped Pb nuclei penetrating various amorphous targets. Concerning the LPM effect, both the 'traditional' Migdal approach and the modern treatment by Baier and Katkov display inaccuracies, i.e. a possible lack of applicability in low-$Z$ targets. Moreover, the LPM effect has been shown to have a significant impact on giant air showers for energies in the EeV range - evidently processes in a low-$Z$ material. A measurement of magnetic suppression is demanding in terms of necessary accuracy (an expected $lesssim$15% effect), but would prove the existence of a basic interplay between coherent and incoherent processes, also believed to be significant in beamstrahlung emission. For...

  14. Coherent Photoproduction of proton anti-proton pair on deiterium with CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Ghandilyan, Yeranuhi Ghandilyan [Yerevan Physics Inst. (YerPhI) (Armenia); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-01-04

    In this project coherent production of proton anti-proton pairs on deuterium with a high energy bremsstrahlung photon beam is studied. The main objective is to study claims of several groups on existence of two meson states, masses ~2.02 GeV and ~2.2 GeV. Coherent production on deuterium has an advantage compared to the production on hydrogen. It will eliminate ambiguities in the production mechanism, since only t-channel production of (p$\\bar{p}$) is allowed.

    Data from the CLAS detector at Jefferson Lab (TJNAF) has been analyzed. The experiment run in 2004-2005 with tagged bremsstrahlung photon beam of up to 5.5 GeV and a 40 cm long liquid deuterium target. During the experiment the CLAS torus magnet polarity was set to bend negatively charged particles outwards from the beam line. During the run the main trigger was tagger hodoscopes in relevant energy region in coincidence with three prong event in CLAS. The reactions γd→p$\\bar{p}$-d, γd→π+π-d, and γd→K+K-d in fully exclusive final states has been analyzed, and the cross sections have been extracted.

  15. MEASUREMENT OF THE HIGH ENERGY COMPONENT OF THE X-RAY SPECTRA INTHE VENUS ECR ION SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Leitner, Daniela; Benitez, Janilee Y.; Lyneis, Claude M.; Todd,Damon S.; Ropponen,Tommi; Ropponen,Janne; Koivisto, Hannu; Gammino, Santo

    2007-11-15

    High performance electron cyclotron resonance (ECR) ion sources, such as VENUS (Versatile ECR for Nuclear Science), produce large amounts of x-rays. By studying their energy spectra, conclusions can be drawn about the electron heating process and the electron confinement. In addition, the bremsstrahlung from the plasma chamber is partly absorbed by the cold mass of the superconducting magnet adding an extra heat load to the cryostat. Germanium or NaI detectors are generally used for x-ray measurements. Due to the high x-ray flux from the source, the experimental set-up to measure bremsstrahlung spectra from ECR ion sources is somewhat different than for the traditional nuclear physics measurements these detectors are generally used for. In particular the collimation and background shielding can be problematic. In this paper we will discuss the experimental set-up for such a measurement, the energy calibration and background reduction, the correction for detector efficiency, the shielding of the detector and collimation of the x-ray flux. We will present x-ray energy spectra and cryostat heating rates in dependence of various ion source parameters such as confinement fields, minimum B-field, rf power and heating frequency.

  16. CORONAL MAGNETIC FIELDS DERIVED FROM SIMULTANEOUS MICROWAVE AND EUV OBSERVATIONS AND COMPARISON WITH THE POTENTIAL FIELD MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Miyawaki, Shun; Nozawa, Satoshi [Department of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Iwai, Kazumasa; Shibasaki, Kiyoto [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Nagano 384-1305 (Japan); Shiota, Daikou, E-mail: shunmi089@gmail.com [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

    2016-02-10

    We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the differential emission measure measurements using EUV observations. We derived line-of-sight components of the coronal magnetic field from polarization observations of the thermal bremsstrahlung in the NOAA active region 11150, observed around 3:00 UT on 2011 February 3 using the Nobeyama Radioheliograph at 17 GHz. Because the thermal bremsstrahlung intensity at 17 GHz includes both chromospheric and coronal components, we extracted only the coronal component by measuring the coronal emission measure in EUV observations. In addition, we derived only the radio polarization component of the corona by selecting the region of coronal loops and weak magnetic field strength in the chromosphere along the line of sight. The upper limits of the coronal longitudinal magnetic fields were determined as 100–210 G. We also calculated the coronal longitudinal magnetic fields from the potential field extrapolation using the photospheric magnetic field obtained from the Helioseismic and Magnetic Imager. However, the calculated potential fields were certainly smaller than the observed coronal longitudinal magnetic field. This discrepancy between the potential and the observed magnetic field strengths can be explained consistently by two reasons: (1) the underestimation of the coronal emission measure resulting from the limitation of the temperature range of the EUV observations, and (2) the underestimation of the coronal magnetic field resulting from the potential field assumption.

  17. Physics of Nonmagnetic Relativistic Thermal Plasmas. Ph.D. Thesis - Calif. Univ., San Diego

    Science.gov (United States)

    Dermer, C. D.

    1984-01-01

    A detailed treatment of the kinematics of relativistic systems of particles and photons is presented. In the case of a relativistic Maxwell-Boltzmann distribution of particles, the reaction rate and luminosity are written as single integrals over the invariant cross section, and the production spectrum is written as a double integral over the cross section differential in the energy of the produced particles (or photons) in the center-of-momentum system of two colliding particles. The results are applied to the calculation of the annihilation spectrum of a thermal electron-positron plasma, confirming previous numerical and analytic results. Relativistic thermal electron-ion and electron-electron bremsstrahlung are calculated exactly to lowest order, and relativistic thermal electron-positron bremsstrahlung is calculated in an approximate fashion. An approximate treatment of relativistic Comptonization is developed. The question of thermalization of a relativistic plasma is considered. A formula for the energy loss or exchange rate from the interaction of two relativistic Maxwell-Boltzmann plasmas at different temperatures is derived. Application to a stable, uniform, nonmagnetic relativistic thermal plasma is made. Comparison is made with other studies.

  18. End-point energy measurements of field emission current in a continuous-wave normal-conducting rf injector

    Science.gov (United States)

    Nguyen, D. C.; Moody, N. A.; Andrews, H. L.; Bolme, G.; Castellano, L. J.; Heath, C. E.; Krawczyk, F. L.; Kwon, S. I.; McCrady, R.; Martinez, F. A.; Marroquin, P.; Prokop, M.; Renneke, R. M.; Roybal, P.; Roybal, W. T.; Tomei, T. L.; Torrez, P. A.; Tuzel, W. M.; Zaugg, T.

    2011-03-01

    The LANL/AES normal-conducting radio-frequency injector has been tested at cw cathode gradients up to 10MV/m. Field-emission electrons from a roughened copper cathode are accelerated to beam energy as high as 2.5 MeV and impinge on a stainless steel target. The energies of the resulting bremsstrahlung photons are measured at varying levels of injector cavity rf power corresponding to different accelerating gradients. At low cavity power, the bremsstrahlung spectra exhibit well-defined end-point energies at the positions where the number of single-photon events decreases to one (S/Nratio=1). Increasing the cavity power raises the probability of two-photon events in which two photons simultaneously arrive at the detector and register counts at twice the photon energy. The end-point energies at high cavity power are recorded at positions where the single-photon events transition to two-photon events. The measured end-point energies using this method are in excellent agreement with PARMELA calculations based on the cavity gradients deduced from the cavity rf power measurements.

  19. Using Photon Activation Analysis To Determine Concentrations Of Unknown Components In Reference Materials

    Science.gov (United States)

    Green, Jaromy; Zaijing, Sun; Wells, Doug; Maschner, Herb

    2011-06-01

    Using certified multi-element reference materials for instrumental analyses one frequently is confronted with the embarrassing fact that the concentration of some desired elements are not given in the respective certificate, nonetheless are detectable, e.g. by photon activation analysis (PAA). However, these elements might be determinable with sufficient quality of the results using scaling parameters and the well-known quantities of a reference element within the reference material itself. Scaling parameters include: activation threshold energy, Giant Dipole Resonance (GDR) peak and endpoint energy of the bremsstrahlung continuum; integrated photo-nuclear cross sections for the isotopes of the reference element; bremsstrahlung continuum integral; target thickness; photon flux density. Photo-nuclear cross sections from the unreferenced elements must be known, too. With these quantities, the integral was obtained for both the known and unknown elements resulting in an inference of the concentration of the unreported element based upon the reported value, thus also the concentration of the unreferenced element in the reference material. A similar method to determine elements using the basic nuclear and experimental data has been developed for thermal neutron activation analysis some time ago (k0 Method).

  20. Neutrino Production of Same Sign Dimuons at the Fermilab Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Sandler, Pamela Helen [Univ. of Wisconsin, Madison, WI (United States)

    1992-01-01

    The rate of neutrino and antineutrino induced same-sign dimuon production was measured using a sample of 220 μ-μ- events and 15 μ+μ+ events, normalized to 1.5 million neutrino-induced charged-current events and 0.3 million antineutrino-induced events with energies between 30 GeV and 600 GeV. The data was obtained with the Chicago-Columbia- Fermilab-Rochester neutrino detector at the Fermilab Tevatron during two experiments, E744 and E770. The CCFR detector is a combined steel target and calorimeter which is followed by a muon-momentum spectrometer. After background subtraction, the prompt rate of same-sign dimuon production is (0.53±0.24)x$10^{-4}$ per charged-current event for neutrinos and (0.52±0.33)x $10^{-4}$ per charged-current events for antineutrinos. These rates are consistent with Standard Model predictions for cc gluon bremsstrahlung and with zero. The kinematic distributions of the same-sign dimuon signal are consistent with those of the nonprompt background due to meson decays in the hadron shower of a charged-current events and cc gluon bremsstrahlung.

  1. Etude de la production de photons a grande impulsion transverse dans les collisions hadroniques avec le detecteur UA2

    CERN Document Server

    Bourliaud, Martial

    NOUS ETUDIONS LA PRODUCTION INCLUSIVE DE PHOTONS A GRANDE IMPULSION TRANSVERSE ET A FAIBLE PSEUDORAPIDITE DANS LES COLLISIONS HADRONIQUES. NOUS PRESENTONS DEUX ANALYSES ORIGINALES REALISEES SUR 13 PICOBARN MOINS UN DE COLLISIONS PROTON-ANTIPROTON COLLECTEES PAR LA COLLABORATION UA2' AUPRES DU COLLISIONNEUR SPPS DU CERN. QCD PREDIT QUE CES PHOTONS SONT SOIT EMIS PAR LES QUARKS LORS DES INTERACTIONS A GRAND MOMENT DE TRANSFERT (PHOTONS DIRECTS), SOIT CREES PAR BREMSSTRAHLUNG LORS DE LA FRAGMENTATION DES JETS. LA SECTION EFFICACE TOTALE DE PRODUCTION DE CES PHOTONS A ETE POUR L'ESSENTIEL CALCULEE A L'APPROXIMATION DES LOGARITHMES SOUS-DOMINANTS, AVEC TOUTEFOIS DES INCERTITUDES SUR LA PROPORTION DE PHOTONS DE BREMSSTRAHLUNG AUX FAIBLES VALEURS DE X#T. DU POINT DE VUE EXPERIMENTAL LES PHOTONS OFFRENT L'AVANTAGE D'ETRE BIEN MIEUX MESURES QUE LES JETS, ET NOS MESURES CONSTITUENT DES TESTS DU MODELE DES PARTONS DE QCD. LES PREDICTIONS THEORIQUES ET LES APPLICATIONS IMPORTANTES DE LA PRODUCTION HADRONIQUE DE PHOTONS E...

  2. Extra dimensions at particle colliders

    Energy Technology Data Exchange (ETDEWEB)

    Dvergsnes, Erik Wolden

    2004-08-01

    This thesis consists of an introduction where we consider different aspects of theories involving extra dimensions, together with four research publications (Papers I-IV) attached at the end. The introductional chapters should serve as background material for better understanding the models on which the articles are based. In Chap. 4 we also present some plots not included in the papers. The topic of Papers I-III is graviton induced Bremsstrahlung. In Paper I we consider the contribution to this process from graviton exchange through gluon-gluon fusion at the LHC, compared to the QED background. Only final-state radiation is considered in Paper I, whereas in Paper II we extend this work to include also the quark-antiquark annihilation with graviton exchange, as well as initial-state radiation for both graviton and Standard Model exchange. Paper III is a study of graviton-induced Bremsstrahlung at e{sup +}e{sup -} colliders, including both initial- and final-state radiation. Paper IV is devoted to a study of the center-edge asymmetry at hadron colliders, an asymmetry which previously had been studied for e{sup +}e{sup -} colliders. The center-edge asymmetry can be used as a method of distinguishing between spin-1 and spin-2 exchange, something which will be of major importance if a signal is observed.

  3. Simulation of e-{gamma}-n targets by FLUKA and measurement of neutron flux at various angles for accelerator based neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Patil, B.J., E-mail: bjp@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India); Chavan, S.T.; Pethe, S.N.; Krishnan, R. [SAMEER, IIT Powai Campus, Mumbai 400 076 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411 007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India)

    2010-10-15

    A 6 MeV Race track Microtron (an electron accelerator) based pulsed neutron source has been designed specifically for the elemental analysis of short lived activation products where the low neutron flux requirement is desirable. The bremsstrahlung radiation emitted by impinging 6 MeV electron on the e-{gamma} primary target, was made to fall on the {gamma}-n secondary target to produce neutrons. The optimisation of bremsstrahlung and neutron producing target along with their spectra were estimated using FLUKA code. The measurement of neutron flux was carried out by activation of vanadium and the measured fluxes were 1.1878 x 10{sup 5}, 0.9403 x 10{sup 5}, 0.7428 x 10{sup 5}, 0.6274 x 10{sup 5}, 0.5659 x 10{sup 5}, 0.5210 x 10{sup 5} n/cm{sup 2}/s at 0{sup o}, 30{sup o}, 60{sup o}, 90{sup o}, 115{sup o}, 140{sup o} respectively. The results indicate that the neutron flux was found to be decreased as increase in the angle and in good agreement with the FLUKA simulation.

  4. Precision measurement of the ratio BR (KS →π+π-e+e-) / BR (KL →π+π-πD0)

    Science.gov (United States)

    Batley, J. R.; Kalmus, G. E.; Lazzeroni, C.; Munday, D. J.; Patel, M.; Slater, M. W.; Wotton, S. A.; Arcidiacono, R.; Bocquet, G.; Ceccucci, A.; Cundy, D.; Doble, N.; Falaleev, V.; Gatignon, L.; Gonidec, A.; Grafström, P.; Kubischta, W.; Marchetto, F.; Mikulec, I.; Norton, A.; Panzer-Steindel, B.; Rubin, P.; Wahl, H.; Goudzovski, E.; Hristov, P.; Kekelidze, V.; Kozhuharov, V.; Litov, L.; Madigozhin, D.; Molokanova, N.; Potrebenikov, Yu.; Stoynev, S.; Zinchenko, A.; Monnier, E.; Swallow, E. C.; Winston, R.; Sacco, R.; Walker, A.; Baldini, W.; Dalpiaz, P.; Frabetti, P. L.; Gianoli, A.; Martini, M.; Petrucci, F.; Savrié, M.; Scarpa, M.; Calvetti, M.; Collazuol, G.; Iacopini, E.; Ruggiero, G.; Bizzeti, A.; Lenti, M.; Veltri, M.; Behler, M.; Eppard, K.; Eppard, M.; Hirstius, A.; Kleinknecht, K.; Koch, U.; Marouelli, P.; Masetti, L.; Moosbrugger, U.; Morales Morales, C.; Peters, A.; Wanke, R.; Winhart, A.; Dabrowski, A.; Fonseca Martin, T.; Szleper, M.; Velasco, M.; Anzivino, G.; Imbergamo, E.; Lamanna, G.; Lubrano, P.; Michetti, A.; Nappi, A.; Piccini, M.; Valdata-Nappi, M.; Cenci, P.; Pepe, M.; Petrucci, M. C.; Cerri, C.; Fantechi, R.; Mannelli, I.; Costantini, F.; Fiorini, L.; Giudici, S.; Pierazzini, G.; Sozzi, M.; Cheshkov, C.; Chèze, J. B.; De Beer, M.; Debu, P.; Gouge, G.; Marel, G.; Mazzucato, E.; Peyaud, B.; Vallage, B.; Holder, M.; Maier, A.; Ziolkowski, M.; Biino, C.; Cartiglia, N.; Clemencic, M.; Lopez, S. Goy; Menichetti, E.; Pastrone, N.; Wislicki, W.; Dibon, H.; Jeitler, M.; Markytan, M.; Neuhofer, G.; Widhalm, L.; NA48/1 Collaboration

    2011-01-01

    The KS →π+π-e+e- decay mode was investigated using the data collected in 2002 by the NA48/1 Collaboration. With about 23 k KS →π+π-e+e- events and 59 k KL →π+π-πD0 normalization decays, the KS →π+π-e+e- branching ratio relative to the KL →π+π-πD0 one was determined to be BR (KS →π+π-e+e-) / BR (KL →π+π-πD0) = (3.28 ±0.06stat ±0.04syst) ×10-2. This result was used to set the upper limit |gE1 /gBR | < 3.0 at 90% CL on the presence, in the decay amplitude, of an E1 direct emission (gE1) term relative to the dominant inner bremsstrahlung (gBR) term. The CP-violating asymmetry Aϕ in the sin ϕcos ϕ distribution of KS →π+π-e+e- events, where ϕ is the angle between the π+π- and the e+e- decay planes in the kaon centre of mass, was found to be Aϕ = (- 0.4 ± 0.8)%, consistent with zero. These results are in good agreement with a description of the KS →π+π-e+e- decay amplitude dominated by the CP-even inner bremsstrahlung process.

  5. Precision measurement of the ratio BR(K→π+π-e+e-)/BR(K→π+π-πD0)

    Science.gov (United States)

    NA48/1 Collaboration; Batley, J. R.; Kalmus, G. E.; Lazzeroni, C.; Munday, D. J.; Patel, M.; Slater, M. W.; Wotton, S. A.; Arcidiacono, R.; Bocquet, G.; Ceccucci, A.; Cundy, D.; Doble, N.; Falaleev, V.; Gatignon, L.; Gonidec, A.; Grafström, P.; Kubischta, W.; Marchetto, F.; Mikulec, I.; Norton, A.; Panzer-Steindel, B.; Rubin, P.; Wahl, H.; Goudzovski, E.; Hristov, P.; Kekelidze, V.; Kozhuharov, V.; Litov, L.; Madigozhin, D.; Molokanova, N.; Potrebenikov, Yu.; Stoynev, S.; Zinchenko, A.; Monnier, E.; Swallow, E. C.; Winston, R.; Sacco, R.; Walker, A.; Baldini, W.; Dalpiaz, P.; Frabetti, P. L.; Gianoli, A.; Martini, M.; Petrucci, F.; Savrié, M.; Scarpa, M.; Calvetti, M.; Collazuol, G.; Iacopini, E.; Ruggiero, G.; Bizzeti, A.; Lenti, M.; Veltri, M.; Behler, M.; Eppard, K.; Eppard, M.; Hirstius, A.; Kleinknecht, K.; Koch, U.; Marouelli, P.; Masetti, L.; Moosbrugger, U.; Morales Morales, C.; Peters, A.; Wanke, R.; Winhart, A.; Dabrowski, A.; Fonseca Martin, T.; Szleper, M.; Velasco, M.; Anzivino, G.; Imbergamo, E.; Lamanna, G.; Lubrano, P.; Michetti, A.; Nappi, A.; Piccini, M.; Valdata-Nappi, M.; Cenci, P.; Pepe, M.; Petrucci, M. C.; Cerri, C.; Fantechi, R.; Mannelli, I.; Costantini, F.; Fiorini, L.; Giudici, S.; Pierazzini, G.; Sozzi, M.; Cheshkov, C.; Chèze, J. B.; de Beer, M.; Debu, P.; Gouge, G.; Marel, G.; Mazzucato, E.; Peyaud, B.; Vallage, B.; Holder, M.; Maier, A.; Ziolkowski, M.; Biino, C.; Cartiglia, N.; Clemencic, M.; Lopez, S. Goy; Menichetti, E.; Pastrone, N.; Wislicki, W.; Dibon, H.; Jeitler, M.; Markytan, M.; Neuhofer, G.; Widhalm, L.

    2011-01-01

    The K→π+π-e+e- decay mode was investigated using the data collected in 2002 by the NA48/1 Collaboration. With about 23 k K→π+π-e+e- events and 59 k K→π+π-πD0 normalization decays, the K→π+π-e+e- branching ratio relative to the K→π+π-πD0 one was determined to be BR(K→π+π-e+e-)/BR(K→π+π-πD0)=(3.28±0.06±0.04)×10-2. This result was used to set the upper limit |g/g|<3.0 at 90% CL on the presence, in the decay amplitude, of an E1 direct emission (g) term relative to the dominant inner bremsstrahlung (g) term. The CP-violating asymmetry A in the sinϕcosϕ distribution of K→π+π-e+e- events, where ϕ is the angle between the π+π- and the e+e- decay planes in the kaon centre of mass, was found to be A=(-0.4±0.8)%, consistent with zero. These results are in good agreement with a description of the K→π+π-e+e- decay amplitude dominated by the CP-even inner bremsstrahlung process.

  6. Fast, accurate photon beam accelerator modeling using BEAMnrc: A systematic investigation of efficiency enhancing methods and cross-section data

    Energy Technology Data Exchange (ETDEWEB)

    Fragoso, Margarida; Kawrakow, Iwan; Faddegon, Bruce A.; Solberg, Timothy D.; Chetty, Indrin J. [Henry Ford Health System, Detroit, Michigan 48202 (United States); National Research Council of Canada, Ottawa, Ontario K1A OR6 (Canada); University of California, San Francisco, California 94143-0226 (United States); UT Southwestern Medical Center, Dallas, Texas 75390-9183 (United States); Henry Ford Health System, Detroit, Michigan 48202 (United States)

    2009-12-15

    In this work, an investigation of efficiency enhancing methods and cross-section data in the BEAMnrc Monte Carlo (MC) code system is presented. Additionally, BEAMnrc was compared with VMC++, another special-purpose MC code system that has recently been enhanced for the simulation of the entire treatment head. BEAMnrc and VMC++ were used to simulate a 6 MV photon beam from a Siemens Primus linear accelerator (linac) and phase space (PHSP) files were generated at 100 cm source-to-surface distance for the 10x10 and 40x40 cm{sup 2} field sizes. The BEAMnrc parameters/techniques under investigation were grouped by (i) photon and bremsstrahlung cross sections, (ii) approximate efficiency improving techniques (AEITs), (iii) variance reduction techniques (VRTs), and (iv) a VRT (bremsstrahlung photon splitting) in combination with an AEIT (charged particle range rejection). The BEAMnrc PHSP file obtained without the efficiency enhancing techniques under study or, when not possible, with their default values (e.g., EXACT algorithm for the boundary crossing algorithm) and with the default cross-section data (PEGS4 and Bethe-Heitler) was used as the ''base line'' for accuracy verification of the PHSP files generated from the different groups described previously. Subsequently, a selection of the PHSP files was used as input for DOSXYZnrc-based water phantom dose calculations, which were verified against measurements. The performance of the different VRTs and AEITs available in BEAMnrc and of VMC++ was specified by the relative efficiency, i.e., by the efficiency of the MC simulation relative to that of the BEAMnrc base-line calculation. The highest relative efficiencies were {approx}935 ({approx}111 min on a single 2.6 GHz processor) and {approx}200 ({approx}45 min on a single processor) for the 10x10 field size with 50 million histories and 40x40 cm{sup 2} field size with 100 million histories, respectively, using the VRT directional bremsstrahlung

  7. Beam polarimetry in the CBELSA/TAPS experiment; Strahlpolarimetrie am CBELSA/TAPS Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kammer, Susanne

    2010-02-19

    In the identification of nucleon resonances polarization observables play an important role. For the photoproduction experiments of the CBELAS/TAPS assembly at the accelerator facility ELSA in the framework of this thesis linearly and circularly polarized were realized and prepared. Linearly polarized photons were produced on a diamond crystal under usage of the coherent bremsstrahlung. By alignment of the crystal in the bremsstrahlung coherent intensity increasements in form of pronounced edges could be generated. The number of the polarized photons lying in the increasement determines in comparison to the incoherently produced background the degree of polarization. The position of the coherent edge could be tuned by means of control distributions to an arbitrary position in the measured energy spectrum as well as the degree of polarization of the photons optimized. For the production of circularly polarized photons longitudinally polarized electrons on the bremsstrahlung target are required. The polarization transfer of the bremsstrahlung process is uniquely given by the QED, so that the degree of polarization of the photons can be determined via a measurement of the electron-beam polarization. With this goal a for the first time in the CBELSA/TAPS applied momentum-selecting Moeller polarimeter was developed and integrated in the photon-tagging facility. Via a change of the beam helicity the counting-rate asymmetry for parallely and antiparallely beam and target electrons was measured and the degree of polarization of the electrons at beam energies of 2350 MeV determined to typically above 60%. By means of dedicated test measurements and simulations the functionality of the Moeller polarimeter was checked and the relative systematic uncertainty determined to 1%. Since 2007 the Moeller polarimeter essential for the double-polarization experiments is in current operation. Finally a method was sketched, in which via the known cross-section asymmetry of the

  8. Application of Monte Carlo Simulation of Total Skin Electron Therapy for Treatment Optimization.

    Science.gov (United States)

    Shokrani, Parvaneh

    A technique for treatment of total skin irradiation was simulated using the Monte Carlo method. By application of this simulation, optimization of the Total Skin Electron Therapy (TSET) technique was accomplished. The purpose of the optimization process was to select the properties of the optimal TSET secondary scatterer. The optimization process was divided into four steps. First, the geometry of the treatment head of a Phillips SL-20 linear accelerator and the geometry of the TSET technique were simulated. Using a combination of the EGS4 Monte Carlo code system, geometry routines, and a package of variance reduction techniques, spectrum of the electron beam, at the exit window of the treatment head and at the treatment plane (located at 300 cm), was calculated. Second, to confirm the accuracy of calculations, the calculated depth dose curves, field uniformity and bremsstrahlung contamination for a control scatterer were compared to the measurement values. Third, a group of materials were selected to perform as a candidate for the optimal TSET scatterer. The treatment field characteristics produced by these materials were calculated and the optimal scatterer was selected. Forth, selection of the optimal scatterer was confirmed by way of physical measurements. Physical measurements showed that the EGS4 Monte Carlo code system, together with the TSET user code, developed in this research, simulated the TSET technique accurately. However there were some problem areas. The central axis surface dose was underestimated by simulations and there was inconsistency associated with radial distribution of bremsstrahlung contamination. Monte Carlo simulation of the TSET technique predicted a 0.059 mm thickness of lead as the optimal scatterer. This scatterer was predicted to produce a minimum uniformity of 73%, a d_{80%} of between 1.8-2.1 cm and a 30% increase in dose rate (as compared to the control scatterer). Moreover, the Monte Carlo simulations TSET technique and

  9. 2005–2010 Multiwavelength Campaing of OJ287

    Directory of Open Access Journals (Sweden)

    M. Valtonen

    2011-01-01

    Full Text Available The light curve of quasar OJ287 extends from 1891 up today without major gaps. This is partly due to extensive studies of historical plate archives by Rene Hudec and associates, and partly due to several observing campaigns in recent times. Here we summarize the results of the 2005–2010 observing campaign, in which several hundred scientists and amateur astronomers took part. The main results are the following: (1 The 2005 October optical outburst came at the expected time, thus confirming the General Relativistic precession in the binary black hole system, as was originally proposed bySillanp¨a¨a et al. (1988. At the same time, this result disproved the model of a single black hole system with accretion disk oscillations, as well as several toy models of binaries without relativistic precession. In the latter models the main outburst would have been a year later. No particular activity was seen in OJ287 in 2006 October. (2 The nature of the radiation of the 2005 October outburst was expected to be bremsstrahlung from hot gas at a temperature of 3 × 105 K. The reason for the outburst is a collision of the secondary on the accretion disk of the primary, which heats the gas to this temperature. This was confirmed by combined ground based and ultraviolet observations using the XMM-Newton X-ray telescope. (3 A secondary outburst of the same nature was expected at 2007 September 13. Within the accuracy of the observations (about 6 hours, it started at the correct time. Thus the prediction was accurate at the same level as the prediction of the return of Halley’s comet in 1986. Due to the bremsstrahlung nature of the outburst, the radiation was unpolarised, as expected. (4 Further synchrotron outbursts were expected following the two bremsstrahlung outbursts.They came as scheduled between 2007 October and 2009 December. (5 Due to the effect of the secondary on the overall direction of the jet, the parsec scale jet was expected to rotate in the

  10. Development of an efficient scanning and purging magnet system for IMRT with narrow high energy photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, Bjoern, E-mail: bjorn.andreassen@gmail.co [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, P.O. Box 260, SE-171 76 Stockholm (Sweden); Svensson, Roger; Holmberg, Rickard [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, P.O. Box 260, SE-171 76 Stockholm (Sweden); Danared, Hakan [Manne Siegbahn Laboratory, Stockholm University, Frescativaegen 26, SE-114 18 Stockholm (Sweden); Brahme, Anders [Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, P.O. Box 260, SE-171 76 Stockholm (Sweden)

    2009-12-21

    Due to the clinical advantages of Intensity Modulated Radiation Therapy (IMRT) high flexibility and accuracy in intensity modulated dose delivery is desirable to really maximize treatment outcome. Although it is possible to deliver IMRT by using broad beams in combination with dynamic multileaf collimation the process is rather time consuming and inefficient. By using narrow scanned high energy photon beams the treatment outcome can be improved, the treatment time reduced and accurate 3D in vivo dose delivery monitoring is possible by PET-CT based dose delivery imaging of photo nuclear reactions in human tissues. Narrow photon beams can be produced by directing a low emittance high energy electron beam on a thin target, and then cleaning the therapeutic photon beam from transmitted high energy electrons, and photon generated charged leptons, with a dedicated purging magnet placed directly downstream of the target. To have an effective scanning and purging magnet system the purging magnet should be placed immediately after the bremsstrahlung target to deflect the transmitted electrons to an efficient electron stopper. In the static electron stopper the electrons should be safely collected independent of the desired direction of the therapeutic scanned photon beam. The SID (Source to Isocenter Distance) should preferably be short while retaining the ability to scan over a large area on the patient and consequently there are severe requirements both on the strength and the geometry of the scanning and purging magnets. In the present study an efficient magnet configuration with a purging and scanning magnet assembly is developed for electron energies in the 50-75 MeV range and a SID of 75 cm. For a bremsstrahlung target of 3 mm Be these electron energies produce a photon beam of 25-17 mm FWHM (Full Width Half Maximum) at a SID of 75 cm. The magnet system was examined both in terms of the efficiency in scanning the narrow bremsstrahlung beam and the deflection of

  11. Gamma radiation in space and in the atmosphere; Rayonnement gamma dans l'espace et dans l'atmosphere

    Energy Technology Data Exchange (ETDEWEB)

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

    1966-07-01

    We have shown that the {gamma} radiation existing in the atmosphere is caused mainly by the Bremsstrahlung of the electrons of the electromagnetic cascades ({approx} 50 per cent of the measured radiation), by the 511 keV radiation produced by the annihilation of positrons created in cascades (8 per cent of the measured intensity) and by the Compton {gamma} degradation of this line (30 per cent of the measured intensity). The rest, slightly over 10 per cent, must be attributed to secondary causes such as the nuclear de-excitation {gamma} to the internal Bremsstrahlung of charged particles created in nuclear stars, and to charged particles crossing our detector, since the latter was not fitted with a device for rejecting these particles. Experiments carried out in rockets at Colomb-Bechar confirm these results and have made it possible to detect and measure a primary {gamma} radiation having an intensity of {approx} 2 {gamma} cm{sup 2} s{sup -1} above 100 keV. The primary spectrum obeys an approximate E{sup -2} law. (author) [French] Nous avons montre que le rayonnement {gamma} existant dans l'atmosphere est provoque principalement por le bremsstrohlung des electrons des cascades electromagnetiques ({approx} 50 pour cent du rayonnement mesure), au rayonnement 511 keV provoque par l'annihilation des positrons crees dans les cascades (8 pour cent de l'intensite mesuree) et aux {gamma} de degradation Compton de cette raie (30 pour cent de l'intensite mesuree). Le reste, soit un peu plus de 10 pour cent, doit etre attribue a des causes secondaires telles que les {gamma} de desexcitation nucleaire, le bremsstrahlung interne des particules chargees creees dans les etoiles nucleaires, et aux particules chargees traversant notre detecteur car celui-ci ne comportait pas de dispositif de rejet de ces particules. Les experiences faites en fusees a Colomb-Bechar ont confirme ces resultats et permis de detecter et mesurer un rayonnement {gamma} primaire dont l

  12. Improving Flare Irradiance Models with the Low Pass Filter Relation Between EUV Flare Emissions with Differing Formation Temperatures

    Science.gov (United States)

    Thiemann, Edward M. B.; Eparvier, Francis G.

    2016-10-01

    Solar flares are the result of magnetic reconnection in the solar corona which converts magnetic energy into kinetic energy resulting in the rapid heating of solar plasma. As this plasma cools, extreme ultraviolet (EUV) line emission intensities evolve as the plasma temperature passes through line formation temperatures, resulting in emission lines with cooler formation temperatures peaking after those with hotter formation temperatures. At the 2016 American Astronomical Society Solar Physics Division Meeting in Boulder (SPD2016), we showed that Fe XVIII solar flare light curves are highly correlated with Fe XXIII light curves that have been subjected to the single-pole Low Pass Filter Equation (LPFE) with a time constant equal to the time difference between the peak emissions. The single-pole (or equivalently, RC) LPFE appears frequently in analyses of systems which both store and dissipate heat, and the flare LPFE effect is believed to be related to the underlying cooling processes. Because the LPFE is constrained by a single parameter, this effect has implications for both operational EUV flare irradiance models and understanding thermal processes that occur in post-flare loops. At the time of SPD2016, it was ambiguous as to whether the LPFE effect relates hot thermal bremsstrahlung soft x-ray (SXR) or EUV line emissions with cooler EUV line emissions since Fe XXIII flare light curves are highly correlated with SXR flare light curves. In this study, we present new results characterizing the LPFE relation between multiple emission lines with differing formation temperatures ranging from 107.2 to 105.7 K observed by SDO/EVE and SXR thermal bremsstrahlung emissions observed by GOES/XRS. We show that the LPFE equation relates Fe XVIII with cooler EUV line emissions, providing unambiguous evidence that the LPFE effect exists between EUV line emissions rather than thermal bremsstrahlung and line emissions exclusively. The exact nature of this effect remains an open

  13. Dimuon production by laser-wakefield accelerated electrons

    Directory of Open Access Journals (Sweden)

    A. I. Titov

    2009-11-01

    Full Text Available We analyze μ^{+}μ^{-} pair production generated by high-energy electrons emerging from a laser-wakefield accelerator. The μ^{+}μ^{-} pairs are created in a solid thick high-Z target, following the electron accelerating plasma region. Numerical estimates are presented for 1 to 10 GeV electron beams which are expected to be reliable in the nearest future. Reactions induced by the secondary bremsstrahlung photons dominate the dimuon production. According to our estimates, a 20 pC electron bunch with energy of 1 (10 GeV may create about 100 (5000 muon pairs. The produced μ^{±} can be used in studying various aspects of muon-related physics in tabletop installations. This may be considered as an important step towards the investigation of more complicated elementary processes induced by laser-driven electrons.

  14. Standard Guide for Dosimetry In Radiation Processing of Fluidized Beds and Fluid Streams

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This guide describes several dosimetry systems and methods suitable for the documentation of the irradiation of product transported as fluid or in a fluidized bed. 1.2 The sources of penetrating ionizing radiation included in this guide are electron beams, X-rays (bremsstrahlung) and gamma rays. 1.3 Absorbed doses from 10 to 100,000 gray are considered, including applications such as disinfestation, disinfection, bioburden reduction, sterilization, crosslinking and graft modification of products, particularly powders and aggregates. 1.4 This guide does not purport to address the safety concerns, if any, associated with the use of fluidized beds and streams incorporating sources of ionizing radiation. It is the responsibility of the user of this guide to establish appropriate safety and health practices and to determine compliance with regulatory limitations prior to use.

  15. Initial performance parameters on FXR

    Energy Technology Data Exchange (ETDEWEB)

    Kulke, B.; Innes, T.G.; Kihara, R.; Scarpetti, R.D.

    1982-06-11

    Construction of the new flash x-ray induction LINAC (FXR) at Lawrence Livermore National Laboratory has been completed. Initial tuning of the machine has produced stable current pulses in excess of 2 kA at the design energy of 20 MeV, with an 80 ns FWHM pulse width, producing single-pulse radiation doses near 500 Roentgen at one meter from the target. The electronic spot size on the bremsstrahlung target is estimated at 3 to 5 mm. In this paper we will discuss the basic FXR design; running-in and tuning of the machine; emittance measurements; beam stability; switch gap synchronization; and measurements of the radiation dose and angular distribution.

  16. Channeling crystals for positron production

    Energy Technology Data Exchange (ETDEWEB)

    Decker, F.J.

    1991-05-01

    Particles traversing at small angles along a single crystal axis experience a collective scattering force of many crystal atoms. The enormous fields can trap the particles along an axis or plane, called channeling. High energy electrons are attracted by the positive nuclei and therefore produce strongly enhanced so called coherent bremsstrahlung and pair production. These effects could be used in a positron production target: A single tungsten crystal is oriented to the incident electron beam within 1 mrad. At 28 GeV/c the effective radiation length is with 0.9 mm about one quarter of the amorphous material. So the target length can be shorter, which yields a higher conversion coefficient and a lower emittance of the positron beam. This makes single crystals very interesting for positron production targets. 18 refs., 2 figs.

  17. Determination of E2 for nitride ceramics using FE-SEM and the Duane-Hunt limit procedure.

    Science.gov (United States)

    Brochu, M; Demers, H; Gauvin, R; Pugh, M D; Drew, R A L

    2005-02-01

    This work demonstrates the possibility of using the Duane-Hunt limit of the bremsstrahlung to determine E2 values of Si3N4 and AlN ceramics. The E(DHL) versus E0 graph demonstrates that for conductive materials, the experimental curve is parallel to the theoretical (E(DHL) = E0), but both curves cross in the case of insulators. The intersection points (E2 value), are 3.01 keV for Si3N4 and 2.67 keV for AlN. Imaging of ceramic grain structure at high magnification was performed to demonstrate the validity of the calculated E2 values.

  18. sup 3 He detectors in experiments at the powerful pulsed accelerators

    CERN Document Server

    Boreiko, V F; Grebenyuk, V M; Ivanov, A I; Kalinin, A I; Krylov, A R; Parzhitsky, S S; Slepnev, V M; Stolupin, V A; Wozniak, J

    2002-01-01

    A possibility of using a thermal neutron detector in the high gamma-quantum and bremsstrahlung fields is considered in the paper. The design of the thermal neutron detector consisting of 10 counters filled with sup 3 He under the pressure of 2 atm and enclosed in the polyethylene moderator is described. The results of measuring the neutron recording efficiency and neutron lifetimes by this detector exposed to a neutron flux from the dt-reaction and from the sup 2 sup 5 sup 2 Cf and Pu-Be sources are reported. The thicknesses of the polyethylene moderator and the Pb layer used for suppression of the background in the fields of powerful electromagnetic radiation are optimized.

  19. Nuclear resonance fluorescence on {sup 87}Rb

    Energy Technology Data Exchange (ETDEWEB)

    Brueckner, Benjamin; Reifarth, Rene; Sonnabend, Kerstin [Goethe Universitaet Frankfurt, Frankfurt am Main (Germany); Glorius, Jan [Goethe Universitaet Frankfurt, Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Savran, Deniz; Isaak, Johann [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Schwengner, Ronald [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)

    2016-07-01

    The aim of the nuclear resonance fluorescence (NRF) investigation of {sup 87}Rb is the determination of the γ-strength function. For the astrophysical s-process, the γ-strength function of this specific nucleus can be used to calculate the cross section of neutron capture on the branching point nucleus {sup 86}Rb. This branching point together with {sup 85}Kr determines the abundance ratio of strontium isotopes, which could be used to probe stellar models. As one part of the {sup 87}Rb campaign, an NRF experiment on {sup 87}Rb has been carried out using bremsstrahlung at 13.2 MeV at ELBE rate at HZDR. An overview of the experimental setup as well as of the preliminary results is given.

  20. Pair creation constrains superluminal neutrino propagation.

    Science.gov (United States)

    Cohen, Andrew G; Glashow, Sheldon L

    2011-10-28

    The OPERA collaboration claims that muon neutrinos with a mean energy of 17.5 GeV travel 730 km from CERN to the Gran Sasso at a speed exceeding that of light by about 7.5 km/s or 25 ppm. However, we show that superluminal neutrinos may lose energy rapidly via the bremsstrahlung of electron-positron pairs (ν → ν + e- + e+). For the claimed superluminal velocity and at the stated mean energy, we find that most of the neutrinos would have suffered several pair emissions en route, causing the beam to be depleted of higher energy neutrinos. This presents a significant challenge to the superluminal interpretation of the OPERA data. Furthermore, we appeal to Super-Kamiokande and IceCube data to establish strong new limits on the superluminal propagation of high-energy neutrinos.

  1. Cascades from nu_E above 1020 eV

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Spencer R.

    2004-12-21

    At very high energies, the Landau-Pomeranchuk-Migdal effect reduces the cross sections for electron bremsstrahlung and photon e{sup +}e{sup -} pair production. The fractional electron energy loss and pair production cross sections drop as the energy increases. In contrast, the cross sections for photonuclear interactions grow with energy. In solids and liquids, at energies above 10{sup 20} eV, photonuclear reactions dominate, and showers that originate as photons or electrons quickly become hadronic showers. These electron-initiated hadronic showers are much shorter (due to the absence of the LPM effect), but wider than purely electromagnetic showers would be. This change in shape alters the spectrum of the electromagnetic and acoustic radiation emitted from the shower. These alterations have important implications for existing and planned searches for radiation from u{sub e} induced showers above 10{sup 20} eV, and some existing limits should be reevaluated.

  2. Electron and photon reconstruction and performance in ATLAS using a dynamical, topological cell clustering-based approach

    CERN Document Server

    The ATLAS collaboration

    2017-01-01

    The electron and photon reconstruction in ATLAS has moved towards the use of a dynamical, topo- logical cell-based approach for cluster building, owing to advancements in the calibration procedure which allow for such a method to be applied. The move to this new technique allows for improved measurements of electron and photon energies, particularly in situations where an electron radiates a bremsstrahlung photon, or a photon converts to an electron-poistron pair. This note details the changes to the ATLAS electron and photon reconstruction software, and assesses its performance under current LHC luminosity conditions using simulated data. Changes to the converted photon reconstruction are also detailed, which improve the reconstruction efficiency of double-track converted photons, as well as reducing the reconstruction of spurious one-track converted photons. The performance of the new reconstruction algorithm is also presented in a number of important topologies relevant to precision Standard Model physics,...

  3. Off-energy-shell behavior of scattering amplitude and the structure of NN potentials

    CERN Document Server

    Almaliev, A N; Shikhalev, M A

    2002-01-01

    For two rather distinct types of NN potentials - with forbidden states and common ones with short-range repulsion - an extensive investigation into off-shell behavior of the scattering amplitudes and associated pp -> pp gamma Bremsstrahlung observables are undertaken. The emphasis is on the action of the shape and deepness of the central part of the potentials on the mentioned quantities. The necessity of taking into consideration the meson-exchange sector of the NN interaction is also stressed. It is shown that, provided one uses potentials which give a good description of phase shifts as well as low off-shell momentum-transfer behavior of the scattering amplitudes, the reaction pp -> pp gamma cannot allow to make a choice between the potentials, at least up to the energy of protons about 400 MeV in laboratory frame

  4. Radiation processes in astrophysics

    CERN Document Server

    Tucker, Wallace H

    1975-01-01

    The purpose of this book is twofold: to provide a brief, simple introduction to the theory of radiation and its application in astrophysics and to serve as a reference manual for researchers. The first part of the book consists of a discussion of the basic formulas and concepts that underlie the classical and quantum descriptions of radiation processes. The rest of the book is concerned with applications. The spirit of the discussion is to present simple derivations that will provide some insight into the basic physics involved and then to state the exact results in a form useful for applications. The reader is referred to the original literature and to reviews for rigorous derivations.The wide range of topics covered is illustrated by the following table of contents: Basic Formulas for Classical Radiation Processes; Basic Formulas for Quantum Radiation Processes; Cyclotron and Synchrotron Radiation; Electron Scattering; Bremsstrahlung and Collision Losses; Radiative Recombination; The Photoelectric Effect; a...

  5. Measurement of isomeric ratios in sup 2 sup 3 sup 2 Th photofission products

    CERN Document Server

    Besshejko, O A; Zheltonozhskij, V A; Strilchuk, N V

    2002-01-01

    Measurement of activity of sup 2 sup 3 sup 2 Th photofission products with T sub 1 sub / sub 2 1 min / 10 h has been carried out using g-spectroscopy technique. The targets were irradiated by Bremsstrahlung gamma-quanta from Mevatron KD2 linear electron accelerator with boundary energy of 23 MeV. Using obtained data about photofission fragments yield isomeric ratios for sup 1 sup 1 7In, sup 1 sup 3 sup 0 Sb, sup 1 sup 3 sup 3 Te, sup 1 sup 3 sup 4 sup g I and sup 1 sup 3 sup 5 Xe nuclei have been measured for the first time at boundary energy of 23 MeV. For the first time mean angular momenta for mentioned above nuclei at sup 2 sup 3 sup 2 Th photofission have been determined.

  6. High Repetition Rate, LINAC-Based Nuclear Resonance Fluorescence FY 2008 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Scott M Watson; Mathew T Kinlaw; James L Jones; Alan W. Hunt; Glen A. Warren

    2008-12-01

    This summarizes the first year of a multi-laboratory/university, multi-year effort focusing on high repetition rate, pulsed LINAC-based nuclear resonance fluorescence (NRF) measurements. Specifically, this FY2008 effort centered on experimentally assessing NRF measurements using pulsed linear electron accelerators, operated at various repetition rates, and identifying specific detection requirements to optimize such measurements. Traditionally, interest in NRF as a detection technology, which continues to receive funding from DHS and DOE/NA-22, has been driven by continuous-wave (CW), Van de Graff-based bremsstrahlung sources. However, in addition to the relatively sparse present-day use of Van de Graff sources, only limited NRF data from special nuclear materials has been presented; there is even less data available regarding shielding effects and photon source optimization for NRF measurements on selected nuclear materials.

  7. Photoproduction of Mesons on Quasi–Free Nucleons

    Directory of Open Access Journals (Sweden)

    Keshelashvili I.

    2014-01-01

    Full Text Available The investigation of excited baryon states is important to understand the underling nature/symmetries of hadronic matter. Historically, the first nucleon excitation experiments have been done using charged pion and kaon secondary beams. Later the antiproton-proton scattering has also been involved. However, since the beginning of the 90’s meson photoproduction reactions have been considered as a powerful tool in baryon spectroscopy. In this contribution, we overview our experimental programs conducted at the bremsstrahlung photon beams of the MAMI accelerator in Mainz and the ELSA accelerator in Bonn. The results are differential and total cross sections for photoproduction of light neutral mesons and of meson pairs off quasi-free nucleons bound in the deuteron (and sometimes other light nuclei. The scientific programs of this experiments also include single and double polarization measurements as well.

  8. Transport at ''NLO'' in hot QCD

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The study of QCD kinetics is driven by a vast array of the experimental measurements of transport at the LHC, ranging from heavy quark energy loss, jet suppression, and hydrodynamics. I first review the fundamental elements of QCD kinetic theory, i.e. plasma screening, 2to2 scattering, and medium modified collinear bremsstrahlung. Then I will summarize recent progress in calculating these elements and their interplay at "NLO" -- "NLO" refers to an order $\\sqrt{\\alpha_s}$ correction to the plasma processes arising from the statistical fluctuations of soft gluons. These "NLO" calculations suggest a computational strategy where the influence of the Debye sector on the real time dynamics of the hard lightlike modes can be incorporated into a few medium coefficients (such as the drag coefficient and $\\hat{q}$), which can be simulated with a Euclidean 3D dimensionally reduced theory.

  9. PHOTOS Monte Carlo for precision simulation of QED in decays

    CERN Document Server

    Was, Z; Nanava, G

    2007-01-01

    Because of properties of QED, the bremsstrahlung corrections to decays of particles or resonances can be calculated, with a good precision, separately from other effects. Thanks to the widespread use of event records such calculations can be embodied into a separate module of Monte Carlo simulation chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo program is used for this purpose since nearly 20 years now. In the following talk let us review the main ideas and constraints which shaped the program version of today and enabled it widespread use. We will concentrate specially on conflicting requirements originating from the properties of QED matrix elements on one side and degrading (evolving) with time standards of event record(s). These issues, quite common in other modular software applications, become more and more difficult to handle as precision requirements become higher.

  10. Absorption of intense microwaves and ion acoustic turbulence due to heat transport

    Energy Technology Data Exchange (ETDEWEB)

    De Groot, J.S.; Liu, J.M. [California Univ., Davis, CA (United States); Matte, J.P. [INRS-Energie (Canada)] [and others

    1994-02-04

    Measurements and calculations of the inverse bremsstrahlung absorption of intense microwaves are presented. The isotropic component of the electron distribution becomes flat-topped in agreement with detailed Fokker-Planck calculations. The plasma heating is reduced due to the flat-topped distributions in agreement with calculations. The calculations show that the heat flux at high microwave powers is very large, q{sub max} {approx} 0.3 n{sub e}v{sub e}T{sub e}. A new particle model to, calculate the heat transport inhibition due to ion acoustic turbulence in ICF plasmas is also presented. One-dimensional PIC calculations of ion acoustic turbulence excited due to heat transport are presented. The 2-D PIC code is presently being used to perform calculations of heat flux inhibition due to ion acoustic turbulence.

  11. Calculations of Energy Losses due to Atomic Processes in Tokamaks with Applications to the ITER Divertor

    CERN Document Server

    Post, D; Clark, R E H; Putvinskaya, N

    1995-01-01

    Reduction of the peak heat loads on the plasma facing components is essential for the success of the next generation of high fusion power tokamaks such as the International Thermonuclear Experimental Reactor (ITER) 1 . Many present concepts for accomplishing this involve the use of atomic processes to transfer the heat from the plasma to the main chamber and divertor chamber walls and much of the experimental and theoretical physics research in the fusion program is directed toward this issue. The results of these experiments and calculations are the result of a complex interplay of many processes. In order to identify the key features of these experiments and calculations and the relative role of the primary atomic processes, simple quasi-analytic models and the latest atomic physics rate coefficients and cross sections have been used to assess the relative roles of central radiation losses through bremsstrahlung, impurity radiation losses from the plasma edge, charge exchange and hydrogen radiation losses f...

  12. CAST constraints on the axion-electron coupling

    CERN Document Server

    Barth, K.; Beltran, B.; Bräuninger, H.; Carmona, J.M.; Collar, J.I.; Dafni, T.; Davenport, M.; Di Lella, L.; Eleftheriadis, C.; Englhauser, J.; Fanourakis, G.; Ferrer-Ribas, E.; Fischer, H.; Franz, J.; Friedrich, P.; Galan, J.; Garcia, J.A.; Geralis, T.; Giomataris, I.; Gninenko, S.; Gomez, H.; Hasinoff, M.D.; Heinsius, F.H.; Hoffmann, D.H.H.; Irastorza, I.G.; Jacoby, J.; Jakovcic, K.; Kang, D.; Königsmann, K.; Kotthaus, R.; Kousouris, K.; Krcmar, M.; Kuster, M.; Lakic, B.; Liolios, A.; Ljubicic, A.; Lutz, G.; Luzon, G.; Miller, D.W.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Redondo, J.; Riege, H.; Rodriguez, A.; Ruz, J.; Savvidis, I.; Semertzidis, Y.; Stewart, L.; Van Bibber, K.; Vieira, J.D.; Villar, J.A.; Vogel, J.K.; Walckiers, L.; Zioutas, K.

    2013-01-01

    In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axio-recombination, the "BCA processes." Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling g_ae and axion-photon interaction strength g_ag using the CAST phase-I data (vacuum phase). For m_a < 10 meV/c2 we find g_ag x g_ae< 8.1 x 10^-23 GeV^-1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission.

  13. A sensitiviy analysis for the stabilization of the CLIC main beam quadrupoles

    CERN Document Server

    Janssens, S; Artoos, K; Fernandez Carmona, P; Hauviller, C

    2010-01-01

    In particle colliders (like the LHC), particles are highly accelerated in a circular beam pipe before the collision. However, due to the curved trajectory of the particles, they are also loosing energy because of the so-called Bremsstrahlung. In order to bypass this fundamental limitation imposed by circular beams, the next generation of particle colliders will accelerate two straight beams of particles before the collision. One of them, the Compact Linear Collider, is currently under study at CERN. The machine is constituted of a huge number of accelerating structures (used to accelerate the particles) and quadrupoles (electromagnets used to focus the particles). The latter ones are required to be stable at the nanometer level. This extreme stability has to be guaranteed by active vibration isolation from all types of disturbances like ground vibrations, ventilation, cooling system, or acoustic noise. Because of the huge number of quadrupoles (about 4000), it is critical that the strategy adopted for the act...

  14. Physical characterization of single convergent beam device for teletherapy: theoretical and Monte Carlo approach.

    Science.gov (United States)

    Figueroa, R G; Valente, M

    2015-09-21

    The main purpose of this work is to determine the feasibility and physical characteristics of a new teletherapy device of radiation therapy based on the application of a convergent x-ray beam of energies like those used in radiotherapy providing highly concentrated dose delivery to the target. We have denominated it Convergent Beam Radio Therapy (CBRT). Analytical methods are developed first in order to determine the dosimetry characteristic of an ideal convergent photon beam in a hypothetical water phantom. Then, using the PENELOPE Monte Carlo code, a similar convergent beam that is applied to the water phantom is compared with that of the analytical method. The CBRT device (Converay(®)) is designed to adapt to the head of LINACs. The converging beam photon effect is achieved thanks to the perpendicular impact of LINAC electrons on a large thin spherical cap target where Bremsstrahlung is generated (high-energy x-rays). This way, the electrons impact upon various points of the cap (CBRT condition), aimed at the focal point. With the X radiation (Bremsstrahlung) directed forward, a system of movable collimators emits many beams from the output that make a virtually definitive convergent beam. Other Monte Carlo simulations are performed using realistic conditions. The simulations are performed for a thin target in the shape of a large, thin, spherical cap, with an r radius of around 10-30 cm and a curvature radius of approximately 70 to 100 cm, and a cubed water phantom centered in the focal point of the cap. All the interaction mechanisms of the Bremsstrahlung radiation with the phantom are taken into consideration for different energies and cap thicknesses. Also, the magnitudes of the electric and/or magnetic fields, which are necessary to divert clinical-use electron beams (0.1 to 20 MeV), are determined using electromagnetism equations with relativistic corrections. This way the above-mentioned beam is manipulated and guided for its perpendicular impact

  15. The HPS experiment at JLab

    Science.gov (United States)

    De Napoli, Marzio

    2017-04-01

    Many Beyond-Standard-Model theories predict a new massive gauge boson, such as a "dark" or "heavy photon". The heavy photon is expected to mix with the Standard Model photon through kinetic mixing and therefore have a small coupling to electric charge. The Heavy Photon Search (HPS) experiment is searching for a heavy photon at the Thomas Jefferson National Accelerator Facility (JLab), in the mass range 20-500 MeV/c2. In particular HPS looks for the e+e- decay channel of heavy photons radiated by electron Bremsstrahlung, employing both an invariant mass search and detached vertexing techniques. The experiment employs a compact forward spectrometer comprising silicon microstrip detectors for vertexing and tracking and an electromagnetic calorimeter for particle identification and triggering. HPS took data successfully in 2015 and 2016 at 1.05 GeV and 2.3 GeV beam energies, respectively. First results are expected to be presented soon.

  16. GlueX overview: status and some future plans

    Science.gov (United States)

    Patsyuk, Maria

    2017-03-01

    The GlueX experiment at Thomas Jefferson National Accelerator Facility (Jefferson Lab) has started data taking in late 2014 with its first commissioning beam. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed. Linearly-polarized photons were successfully produced through coherent bremsstrahlung. An upgrade of the particle identification (PID) system with a GlueX DIRC detector, planned for 2018, will allow identification of final state kaons. The construction of the GlueX DIRC has already started. One of the plans for GlueX is to study properties of short-range correlations (SRC) in nuclei, which will shed new light on the quark-gluon structure of bound nucleons.

  17. Solar neutrino flux at keV energies

    Science.gov (United States)

    Vitagliano, Edoardo; Redondo, Javier; Raffelt, Georg

    2017-12-01

    We calculate the solar neutrino and antineutrino flux in the keV energy range. The dominant thermal source processes are photo production (γ e→ e νbar nu), bremsstrahlung (e+Ze→ Ze+e+νbar nu), plasmon decay (γ→νbar nu), and νbar nu emission in free-bound and bound-bound transitions of partially ionized elements heavier than hydrogen and helium. These latter processes dominate in the energy range of a few keV and thus carry information about the solar metallicity. To calculate their rate we use libraries of monochromatic photon radiative opacities in analogy to a previous calculation of solar axion emission. Our overall flux spectrum and many details differ significantly from previous works. While this low-energy flux is not measurable with present-day technology, it could become a significant background for future direct searches for keV-mass sterile neutrino dark matter.

  18. 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.

  19. APEX: A Prime EXperiment at Jefferson Lab - Test Run Results and Full Run Plans; Update

    Energy Technology Data Exchange (ETDEWEB)

    Beacham, James [Ohio University, JLAB

    2015-06-01

    APEX is an experiment at Thomas Jefferson National Accelerator Facility (JLab) in Virginia, USA, that searches for a new gauge boson (A') with sub-GeV mass and coupling to ordinary matter of g' ~ (10-6 - 10⁻²)e. Electrons impinge upon a fixed target of high-Z material. An A' is produced via a process analogous to photon bremsstrahlung, decaying to an e⁺+e⁻ pair. A test run was held in July of 2010, covering mA' = 175 to 250 MeV and couplings g'/e > 10⁻³. A full run is approved and will cover mA' ~ 65 to 525 MeV and g'/e > 2.3 x 10⁻⁴, and is expected to occur sometime in 2016 or 2017.

  20. Generalized polarizabilities of the nucleon in baryon chiral perturbation theory

    Science.gov (United States)

    Lensky, Vadim; Pascalutsa, Vladimir; Vanderhaeghen, Marc

    2017-02-01

    The nucleon generalized polarizabilities (GPs), probed in virtual Compton scattering (VCS), describe the spatial distribution of the polarization density in a nucleon. They are accessed experimentally via the process of electron-proton bremsstrahlung (ep→ epγ ) at electron-beam facilities, such as MIT-Bates, CEBAF (Jefferson Lab), and MAMI (Mainz). We present the calculation of the nucleon GPs and VCS observables at next-to-leading order in baryon chiral perturbation theory (Bχ PT), and confront the results with the empirical information. At this order our results are predictions, in the sense that all the parameters are well known from elsewhere. Within the relatively large uncertainties of our calculation we find good agreement with the experimental observations of VCS and the empirical extractions of the GPs. We find large discrepancies with previous chiral calculations - all done in heavy-baryon χ PT (HBχ PT) - and discuss the differences between Bχ PT and HBχ PT responsible for these discrepancies.

  1. First observation and branching fraction and decay parameter measurements of the weak radiative decay $\\Xi^0 \\to \\Lambda e^{+}e^{-}$

    CERN Document Server

    Batley, J Richard; Lazzeroni, C; Munday, D J; Patel, M; Slater, M W; Wotton, S A; Arcidiacono, R; Bocquet, G; Ceccucci, A; Cundy, Donald C; Doble, N; Falaleev, V; Gatignon, L; Gonidec, A; Grafstrm, P; Kubischta, Werner; Mikulec, I; Norton, A; Panzer-Steindel, B; Rubin, P; Wahl, H; Goudzovski, E; Khristov, P Z; Kekelidze, V D; Litov, L; Madigozhin, D T; Molokanova, N A; Potrebenikov, Yu K; Stoynev, S; Zinchenko, A I; Monnier, E; Swallow, E; Winston, R; Sacco, R; Walker, A; Baldini, W; Dalpiaz, P; Frabetti, P L; Gianoli, A; Martini, M; Petrucci, F; Savrié, M; Scarpa, M; Bizzeti, A; Calvetti, M; Collazuol, G; Iacopini, E; Lenti, M; Veltri, M; Ruggiero, G; Behler, M; Eppard, K; Eppard, M; Hirstius, A; Kleinknecht, K; Koch, U; Marouelli, P; Masetti, L; Moosbrugger, U; Morales-Morales, C; Peters, A; Wanke, R; Winhart, A; Dabrowski, A; Fonseca-Martin, T; Velasco, M; Anzivino, Giuseppina; Cenci, P; Imbergamo, E; Lamanna, G; Lubrano, P; Michetti, A; Nappi, A; Pepé, M; Valdata, M; Petrucci, M C; Piccini, M; Cerri, C; Costantini, F; Fantechi, R; Fiorini, L; Giudici, S; Mannelli, I; Pierazzini, G M; Sozzi, M; Cheshkov, C; Chèze, J B; De Beer, M; Debu, P; Gouge, G; Marel, Gérard; Mazzucato, E; Peyaud, B; Vallage, B; Holder, M; Maier, A; Ziolkowski, M; Biino, C; Cartiglia, N; Clemencic, M; Goy-Lopez, S; Marchetto, F; Menichetti, E; Pastrone, N; Wislicki, W; Dibon, Heinz; Jeitler, Manfred; Markytan, Manfred; Neuhofer, G; Widhalm, L

    2007-01-01

    The weak radiative decay $Xi^0 -> \\Lambda e^+ e^- $ has been detected for the first time. We find 412 candidates in the signal region, with an estimated background of $15pm 5$ events. We determine the branching fraction ${cal{B}}(\\Xi^0 -> \\Lambda e^+ e^- ) = [7.6pm 0.4({m stat})pm 0.4({m syst})pm 0.2({m norm})] imes 10^{-6}$, consistent with an internal bremsstrahlung process, and the decay asymmetry parameter $\\alpha_{\\Xi \\Lambda ee} = -0.8pm 0.2$, consistent with that of $\\Xi^0 -> \\Lambda \\gamma$. The charge conjugate reaction $\\overline{\\Xi^{0}} -> \\overline{\\Lambda} e^+ e^- $ has also been observed.

  2. Kooperative Produktion von neutralen Pionen und hochenergetischen Photonen in Kern-Kern-Stössen bei 60-84 MeV/u

    CERN Document Server

    Noll, H

    1985-01-01

    The described experiments which were performed at the CERN synchrocyclotron with different target-projectile combinations at different beam energies allow a systematic of the pion production in nucleus-nucleus collisions below the threshold. Thereby the pion production shows clearly the existence of collective effects in the nucleus-nucleus collision in the energy range of 60-84 MeV/u: 1.) The measured cross sections exceed those predicted in the simple nucleon-nucleon collision with Fermi motion by more than one order of magnitude. 2.) The mean velocity determined from the longitudinal rapidity cannot be explained by single nucleon collisions. 3.) The model of the collective pionic bremsstrahlung describes well both the excitation function, the energy spectra, and the angular distribution. Thereby result slow stopping ranges which indicates, that the pions in the collision are produced only during a short time. For the asymmetric systems in the rapidity distribution for low pion energies a structure in the d...

  3. Soft X-ray observations of the supernova remnants HB 3 and 3C 58

    Science.gov (United States)

    Galas, C. M. F.; Tuohy, I. R.; Garmire, G. P.

    1980-01-01

    The HEAO 1 A-2 low energy detectors have discovered soft X-ray emission from a source positionally coincident with the supernova remnant HB 3. The flux in the energy range 0.3-2.2 keV is about 6 x 10 to the -11th ergs per sq cm s. The spectral data are fitted to a hydrogen thermal bremsstrahlung model, and the physical parameters of the supernova remnant are estimated. The age derived is about 21,000 years, and the initial blast energy is about 3.1 x 10 to the 50th ergs. Upper limits to the soft X-ray flux and the luminosity of the supernova remnant 3 C 58 are also derived.

  4. The investigation of inertial fusion burning requirements of deuterium-helium3 in degenerate plasma

    Science.gov (United States)

    Nazirzadeh, M.; Khanbabaei, B.; Ghasemizad, A.

    2017-08-01

    Conditions for self-sustained burning of deuterium-helium3 as an advanced fuel in a degenerate regime have been investigated by the four temperature theory. The four temperature theory can describe the radiation field more accurately than the three temperature model. According to the four temperature theory, the photon distribution undergoes a transition from an optically thick to optically thin regime at a certain cut-off energy. The main goal of this research is to determine the critical burn-up parameter for deuterium-helium3 fuel in the degenerate regime in which the ion-electron energy exchange and the bremsstrahlung loss are smaller than those of the classic plasma. To prevent high tritium breeding via deuterium-deuterium and deuterium-tritium reactions, the utilization of equimolar deuterium-helium3 fuel is avoided.

  5. Gamma beams generation with high intensity lasers for two photon Breit-Wheeler pair production

    Science.gov (United States)

    D'Humieres, Emmanuel; Ribeyre, Xavier; Jansen, Oliver; Esnault, Leo; Jequier, Sophie; Dubois, Jean-Luc; Hulin, Sebastien; Tikhonchuk, Vladimir; Arefiev, Alex; Toncian, Toma; Sentoku, Yasuhiko

    2017-10-01

    Linear Breit-Wheeler pair creation is the lowest threshold process in photon-photon interaction, controlling the energy release in Gamma Ray Bursts and Active Galactic Nuclei, but it has never been directly observed in the laboratory. Using numerical simulations, we demonstrate the possibility to produce collimated gamma beams with high energy conversion efficiency using high intensity lasers and innovative targets. When two of these beams collide at particular angles, our analytical calculations demonstrate a beaming effect easing the detection of the pairs in the laboratory. This effect has been confirmed in photon collision simulations using a recently developed innovative algorithm. An alternative scheme using Bremsstrahlung radiation produced by next generation high repetition rate laser systems is also being explored and the results of first optimization campaigns in this regime will be presented.

  6. DARHT-II Downstream Beam Transport Beamline

    Energy Technology Data Exchange (ETDEWEB)

    Westenskow, G A; Bertolini, L R; Duffy, P T; Paul, A C

    2000-08-01

    This paper describes the mechanical design of the downstream beam transport line for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT II) Facility. The DARHT-II project is a collaboration between LANL, LBNL and LLNL. DARHT II is a 20-MeV, 2000-Amperes, 2-{micro}sec linear induction accelerator designed to generate short bursts of x-rays for the purpose of radiographing dense objects. The downstream beam transport line is approximately 20-meter long region extending from the end of the accelerator to the bremsstrahlung target. Within this proposed transport line there are 15 conventional solenoid, quadrupole and dipole magnets; as well as several specialty magnets, which transport and focus the beam to the target and to the beam dumps. There are two high power beam dumps, which are designed to absorb 80-kJ per pulse during accelerator start-up and operation. Aspects of the mechanical design of these elements are presented.

  7. Measurement of polarisation observables in K{sub s}{sup 0}Σ{sup +} photoproduction off the proton

    Energy Technology Data Exchange (ETDEWEB)

    Ewald, R. [Physikalisches Institut, Universität Bonn (Germany); Anisovich, A.V. [Helmholtz Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bantes, B. [Physikalisches Institut, Universität Bonn (Germany); Bartholomy, O. [Helmholtz Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Bayadilov, D. [Helmholtz Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Beck, R. [Helmholtz Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Beloglazov, Y.A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Brinkmann, K.-T. [II. Physikalisches Institut, Universität Gießen (Germany); Crede, V. [Department of Physics, Florida State University, Tallahassee (United States); Dutz, H.; Elsner, D.; Fornet-Ponse, K.; Frommberger, F. [Physikalisches Institut, Universität Bonn (Germany); Funke, Ch. [Helmholtz Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Gridnev, A.B. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Gutz, E. [II. Physikalisches Institut, Universität Gießen (Germany); Hannappel, J.; Hillert, W. [Physikalisches Institut, Universität Bonn (Germany); and others

    2014-11-10

    The reaction γp→K{sub S}{sup 0}Σ{sup +} is studied in the photon energy range from threshold. Linearly polarised photon beams from coherent bremsstrahlung enabled the first measurement of photon beam asymmetries in this reaction up to E{sub γ}=1650 MeV. In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay Σ{sup +}→pπ{sup 0} up to E{sub γ}=2250 MeV. The data are compared to partial wave analyses, and the possible impact on the interpretation of a recently observed prominent structure in the cross section near the K{sup *} thresholds is discussed.

  8. The CMS all silicon Tracker simulation

    CERN Document Server

    Biasini, Maurizio

    2009-01-01

    The Compact Muon Solenoid (CMS) tracker detector is the world's largest silicon detector with about 201 m$^2$ of silicon strips detectors and 1 m$^2$ of silicon pixel detectors. It contains 66 millions pixels and 10 million individual sensing strips. The quality of the physics analysis is highly correlated with the precision of the Tracker detector simulation which is written on top of the GEANT4 and the CMS object-oriented framework. The hit position resolution in the Tracker detector depends on the ability to correctly model the CMS tracker geometry, the signal digitization and Lorentz drift, the calibration and inefficiency. In order to ensure high performance in track and vertex reconstruction, an accurate knowledge of the material budget is therefore necessary since the passive materials, involved in the readout, cooling or power systems, will create unwanted effects during the particle detection, such as multiple scattering, electron bremsstrahlung and photon conversion. In this paper, we present the CM...

  9. Emittance growth in the DARHT Axis-II Downstream Transport

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Jr., Carl August [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-14

    Using a particle-in-cell (PIC) code, we investigated the possibilities for emittance growth through the quadrupole magnets of the system used to transport the high-current electron beam from an induction accelerator to the bremsstrahlung converter target used for flash radiography. We found that even highly mismatched beams exhibited little emittance growth (< 6%), which we attribute to softening of their initial hard edge current distributions. We also used this PIC code to evaluate the accuracy of emittance measurements using a solenoid focal scan following the quadrupole magnets. If the beam is round after the solenoids, the simulations indicate that the measurement is highly accurate, but it is substantially inaccurate for elliptical beams

  10. Beam Energy Considerations for Gold Nano-Particle Enhanced Radiation Treatment

    CERN Document Server

    Heuvel, F Van den; Nuyts, S

    2009-01-01

    Purpose: A novel approach using nano technology enhanced radiation modalities is investigated. The proposed methodology uses antibodies labeled with organically inert metals with a high atomic number. Irradiation using photons with energies in the kilo--electron volt (keV) range show an increase in dose due to a combination of an increase in photo-electric interactions and a pronounced generation of Auger and/or Coster-Kronig (A-CK) electrons. Methods: The dependency of the dose deposition on various factors is investigated using Monte Carlo simulation models. The factors investigated include: agent concentration, spectral dependency looking at mono--energetic sources as well as classical bremsstrahlung sources. The optimization of the energy spectrum is performed in terms of physical dose enhancement as well as the dose deposited by Auger and/or Coster-Kronig electrons and their biological effectiveness. Results: A quasi-linear dependency on concentration and an exponential decrease within the target medium ...

  11. High-energy-density electron beam from interaction of two successive laser pulses with subcritical-density plasma

    Directory of Open Access Journals (Sweden)

    J. W. Wang

    2016-02-01

    Full Text Available It is shown by particle-in-cell simulations that a narrow electron beam with high energy and charge density can be generated in a subcritical-density plasma by two consecutive laser pulses. Although the first laser pulse dissipates rapidly, the second pulse can propagate for a long distance in the thin wake channel created by the first pulse and can further accelerate the preaccelerated electrons therein. Given that the second pulse also self-focuses, the resulting electron beam has a narrow waist and high charge and energy densities. Such beams are useful for enhancing the target-back space-charge field in target normal sheath acceleration of ions and bremsstrahlung sources, among others.

  12. A new numerical technique to design satellite energetic electron detectors

    CERN Document Server

    Tuszewski, M G; Ingraham, J C

    2002-01-01

    Energetic charged particles trapped in the magnetosphere are routinely detected by satellite instruments. However, it is generally difficult to extract quantitative energy and angular information from such measurements because the interaction of energetic electrons with matter is rather complex. Beam calibrations and Monte-Carlo (MC) simulations are often used to evaluate a flight instrument once it is built. However, rules of thumb and past experience are common tools to design the instrument in the first place. Hence, we have developed a simple numerical procedure, based on analytical probabilities, suitable for instrumental design and evaluation. In addition to the geometrical response, the contributions of surface backscattering, edge penetration, and bremsstrahlung radiation are estimated. The new results are benchmarked against MC calculations for a simple test case. Complicated effects, such as the contribution of the satellite to the instrumental response, can be estimated with the new formalism.

  13. Branes from light: embeddings and energetics for symmetric k-quarks in N=4 SYM

    Energy Technology Data Exchange (ETDEWEB)

    Fiol, Bartomeu [Departament de Física Fonamental i Institut de Ciències del Cosmos,Universitat de Barcelona,Marti i Franquès 1, 08028 Barcelona, Catalonia (Spain); Güijosa, Alberto [Departamento de Física de Altas Energías,Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México,Apartado Postal 70-543, México D.F. 04510 (Mexico); Pedraza, Juan F. [Theory Group, Department of Physics and Texas Cosmology Center, University of Texas,1 University Station C1608, Austin, TX 78712 (United States); Perimeter Institute for Theoretical Physics,31 Caroline St, Waterloo, Ontario N2L 2Y5 (Canada)

    2015-01-29

    We construct the D3-brane dual to a k-quark of N=4 super-Yang-Mills theory in the totally symmetric representation of SU(N), undergoing arbitrary motion. Our method of construction generalizes previous work by Mikhailov, and proceeds by shooting light rays inward from the anti-de Sitter boundary, to trace out the brane embedding. We expect this method to have wider relevance, and provide evidence for this by showing that it correctly reproduces the known D5-brane embeddings dual to totally antisymmetric k-quarks. As an application of our solutions, we compute the energy of the D3-brane and extract from it the k-quark’s intrinsic energy and rate of radiation. The result matches expectations based on previous calculations, and makes contact with the exact Bremsstrahlung function for the fundamental representation.

  14. Exact results for Wilson loops in arbitrary representations

    Energy Technology Data Exchange (ETDEWEB)

    Fiol, Bartomeu; Torrents, Genís [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain)

    2014-01-08

    We compute the exact vacuum expectation value of 1/2 BPS circular Wilson loops of N=4 U(N) super Yang-Mills in arbitrary irreducible representations. By localization arguments, the computation reduces to evaluating certain integrals in a Gaussian matrix model, which we do using the method of orthogonal polynomials. Our results are particularly simple for Wilson loops in antisymmetric representations; in this case, we observe that the final answers admit an expansion where the coefficients are positive integers, and can be written in terms of sums over skew Young diagrams. As an application of our results, we use them to discuss the exact Bremsstrahlung functions associated to the corresponding heavy probes.

  15. New limits on naturally occurring electron capture of 123Te

    Science.gov (United States)

    Alessandrello, A.; Arnaboldi, C.; Brofferio, C.; Capelli, S.; Cremonesi, O.; Fiorini, E.; Nucciotti, A.; Pavan, M.; Pessina, G.; Pirro, S.; Previtali, E.; Sisti, M.; Vanzini, M.; Zanotti, L.; Giuliani, A.; Pedretti, M.; Bucci, C.; Pobes, C.

    2003-01-01

    Electron capture of 123Te from the K shell has been investigated in a new underground search with an array of 340-g TeO2 thermal detectors. We find that some previous indication of this decay could be attributed to electron capture (EC) of 121Te resulting from neutron activation of natural tellurium. There is therefore so far no evidence for EC of 123Te from the K shell with a 90% C.L. lower limit tK1/2>5×1019 years on the half lifetime. Taking into account the predicted K EC branching ratio, the corresponding lower limit on the 123Te EC half lifetime is t1/2>9.2×1016, which can be theoretically interpreted only on the basis of a strong suppression of the nuclear matrix elements. A complementary analysis based on the expected fraction of EC accompanied by internal bremsstrahlung is discussed.

  16. Exotic Hybrid Meson Spectroscopy with the GlueX detector at Jlab

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, David W. [JLAB

    2014-03-01

    The GlueX experiment is scheduled to begin taking data in 2015. The goal is to discover evidence for the existence of exotic hybrid mesons and to map out their spectrum in the light quark sector. Recent theoretical developments using Lattice QCD predict exotic hybrid states in a mass range accessible using the newly upgraded 12GeV electron accelerator at Jefferson Lab. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. The experiment will use 9 GeV linearly polarized photons produced via coherent bremsstrahlung to produce the exotic hybrids. The decay products will be detected in the solenoid-based GlueX detector currently under construction at Jefferson Lab. The status of the GlueX experiment including detector parameters will be presented along with theoretical motivation for the experiment.

  17. Free-free absorption coefficients and Gaunt factors for dense hydrogen-like stellar plasma

    Science.gov (United States)

    Srećković, V. A.; Sakan, N.; Šulić, D.; Jevremović, D.; Ignjatović, Lj M.; Dimitrijević, M. S.

    2018-03-01

    In this work, we present a study dedicated to determination of the inverse bremsstrahlung absorption coefficients and the corresponding Gaunt factor of dense hydrogen-like stellar-atmosphere plasmas where electron density and temperature change in a wide range. A method suitable for this wide range is suggested and applied to the inner layers of the solar atmosphere, as well as the plasmas of partially ionized layers of some other stellar atmospheres (for example, some DA and DB white dwarfs) where the electron densities vary from 1014 cm-3 to 1020 cm-3 and temperatures from 6000 K to 300 000 K in the wavelength region of 10 nm ≤ λ ≤ 3000 nm. The results of the calculations are illustrated by the corresponding figures and tables.

  18. Generic radiation safety design for SSRL synchrotron radiation beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Liu, James C. [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), MS 48, P.O. Box 20450, Stanford, CA 94309 (United States)]. E-mail: james@slac.stanford.edu; Fasso, Alberto [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), MS 48, P.O. Box 20450, Stanford, CA 94309 (United States); Khater, Hesham [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), MS 48, P.O. Box 20450, Stanford, CA 94309 (United States); Prinz, Alyssa [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), MS 48, P.O. Box 20450, Stanford, CA 94309 (United States); Rokni, Sayed [Radiation Protection Department, Stanford Linear Accelerator Center (SLAC), MS 48, P.O. Box 20450, Stanford, CA 94309 (United States)

    2006-12-15

    To allow for a conservative, simple, uniform, consistent, efficient radiation safety design for all SSRL beamlines, a generic approach has been developed, considering both synchrotron radiation (SR) and gas bremsstrahlung (GB) hazards. To develop the methodology and rules needed for generic beamline design, analytic models, the STAC8 code, and the FLUKA Monte Carlo code were used to pre-calculate sets of curves and tables that can be looked up for each beamline safety design. Conservative beam parameters and standard targets and geometries were used in the calculations. This paper presents the SPEAR3 beamline parameters that were considered in the design, the safety design considerations, and the main pre-calculated results that are needed for generic shielding design. In the end, the rules and practices for generic SSRL beamline design are summarized.

  19. ANALYSIS AND MITIGATION OF X-RAY HAZARD GENERATED FROM HIGH INTENSITY LASER-TARGET INTERACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, R.; Liu, J.C.; Prinz, A.A.; Rokni, S.H.; Woods, M.; Xia, Z.; /SLAC

    2011-03-21

    Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.

  20. Framing and localization in Chern-Simons theories with matter

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, Marco S. [Center for Research in String Theory - School of Physics and Astronomy,Queen Mary University of London,Mile End Road, London E1 4NS (United Kingdom); Griguolo, Luca [Dipartimento di Fisica e Scienze della Terra, Università di Parma andINFN Gruppo Collegato di Parma,Viale G.P. Usberti 7/A, 43100 Parma (Italy); Leoni, Matias [Physics Department, FCEyN-UBA & IFIBA-CONICET,Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Mauri, Andrea [Dipartimento di Fisica, Università degli studi di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Penati, Silvia [Dipartimento di Fisica, Università degli studi di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); INFN, Sezione di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Seminara, Domenico [Dipartimento di Fisica, Università di Firenze and INFN Sezione di Firenze,via G. Sansone 1, 50019 Sesto Fiorentino (Italy)

    2016-06-22

    Supersymmetric localization provides exact results that should match QFT computations in some regularization scheme. The agreement is particularly subtle in three dimensions where complex answers from localization procedure sometimes arise. We investigate this problem by studying the expectation value of the 1/6 BPS Wilson loop in planar ABJ(M) theory at three loops in perturbation theory. We reproduce the corresponding term in the localization result and argue that it originates entirely from a non-trivial framing of the circular contour. Contrary to pure Chern-Simons theory, we point out that for ABJ(M) the framing phase is a non-trivial function of the couplings and that it potentially receives contributions from vertex-like diagrams. Finally, we briefly discuss the intimate link between the exact framing factor and the Bremsstrahlung function of the 1/2-BPS cusp.

  1. Energy clustering, Calibration and Particle Identification with the CMS Preshower detector

    CERN Document Server

    Chang, Chiu-ping

    2013-01-01

    The Preshower detector is located in front of the CMS endcap electromagnetic calorimeter. It is a sampling detector with two layers of lead absorber, each followed by 1.9 mm pitch silicon strip sensors. The 4288 DC-coupled sensors each have an active area of 61 x 61 mm$^2$, with a total surface area of around 16 m$^2$, the largest ever built. The Preshower was installed to improve gamma/pi0 discrimination. The Preshower energy clustering algorithms and calibration strategies are described. The algorithms have been improved to deal with bremsstrahlung and photon conversions due to the tracker material in front of the Preshower. Improved photon identification, for physics analyses such as Higgs decays to two photons, as well as improved electron identification in the endcap region of CMS are discussed.

  2. Studies of photon spectra from a thallium-204 foil source as an aid to dosimetry and shielding

    CERN Document Server

    Francis, T M

    1976-01-01

    Beta ray foil sources incorporating nuclides such as thallium-204, promethium-147 and strontium-90 plus yttrium-90 ar increasingly used in industrial devices such as thickness gauges. These sources are so constructed that they give rise to complex photon spectra containing low energy Bremsstrahlung and X-rays characteristic of the constructional materials. The energy response of practical monitoring instruments is such that they are likely to underestimate the dose due to such spectra unless they are calibrated using appropriate spectra. This report describes a series of measurements carried out on a commercially available thallium-204 foil source and five commonly used shielding materials. The measurements made with a NaI(T1) spectrometer have been corrected for instrumental distortions to obtain the photon spectra in air. These spectra are presented and have been used to compute dose in air with the help of published data on mass energy-absorption coefficients. Also included in the report are data derived f...

  3. Electron specific track fitters and Jpsi resonance studies in ATLAS

    CERN Document Server

    Cheatham, Susan

    This thesis discusses the reconstruction of J/psi to electron pairs based on fully simulated ATLAS Monte Carlo samples. A possible trigger strategy is described, taking advantage of the possible presence of a muon in the final state in bb production once one b-hadron decays into J/psi+X, followed by J/psi decay into e+e-. The tracks belonging to low-energy electrons are reconstructed using a dedicated algorithm, taking into account bremsstrahlung effects. The performance of this algorithm is compared with the other ATLAS track fitters and the potential of using this tracking algorithm to map the Inner Detector material is presented. The improvement in separation of indirect from prompt J/psi, by separately considering two kinematical configurations, `cowboys' and `sailors', is also presented, along with a feasibility study of measuring the ratio of indirect to prompt J/psi.

  4. Feynman variance for neutrons emitted from photo-fission initiated fission chains - a systematic simulation for selected speacal nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

    Soltz, R. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Danagoulian, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sheets, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Korbly, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hartouni, E. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-05-22

    Theoretical calculations indicate that the value of the Feynman variance, Y2F for the emitted distribution of neutrons from ssionable exhibits a strong monotonic de- pendence on a the multiplication, M, of a quantity of special nuclear material. In 2012 we performed a series of measurements at the Passport Inc. facility using a 9- MeV bremsstrahlung CW beam of photons incident on small quantities of uranium with liquid scintillator detectors. For the set of objects studies we observed deviations in the expected monotonic dependence, and these deviations were later con rmed by MCNP simulations. In this report, we modify the theory to account for the contri- bution from the initial photo- ssion and benchmark the new theory with a series of MCNP simulations on DU, LEU, and HEU objects spanning a wide range of masses and multiplication values.

  5. Electromagnetic Radiation of Electrons in Periodic Structures

    CERN Document Server

    Potylitsyn, Alexander Petrovich

    2011-01-01

    Periodic magnetic structures (undulators) are widely used in accelerators to generate monochromatic undulator radiation (UR) in the range from far infrared to the hard X-ray region. Another periodic crystalline structure is used to produce quasimonochromatic polarized photon beams via the coherent bremsstrahlung mechanism (CBS). Due to such characteristics as monochromaticity, polarization and adjustability, these types of radiation is of large interest for applied and basic research of accelerator-emitted radiation. The book provides a detailed overview of the fundamental principles behind electromagnetic radiation emitted from accelerated charged particles (e.g. UR, CBS, radiation of fast electrons in Laser flash fields) as well as a unified description of relatively new radiation mechanisms which attracted great interest in recent years. This are the so-called polarization radiation excited by the Coulomb field of incident particles in periodic structures, parametric X-rays, resonant transition radiation a...

  6. Relativistic Electrons in Electric Discharges

    DEFF Research Database (Denmark)

    Cinar, Deniz

    to these conditions, with exception of the electric _eld magnitude where the photon distribution becomes progressively more forward directed for increasing _eld magnitude. However, exploring photon transport to the top of the atmosphere, the angular beaming properties were found to wash out because of Compton...... breakdown _eld appears plausible for TGF generation, because it minimizes the electron avalanche time and length and the total electric potential required.......Thunderstorms generate bursts of X- and Gamma radiation. When observed from spacecraft, the bursts are referred to as “Terrestrial Gamma-ray Flashes” (TGFs). They are bremsstrahlung from energetic electrons accelerated in thunderstorm electric _elds. The TGFs were _rst observed in the 90ties...

  7. Exotic dense-matter states pumped by a relativistic laser plasma in the radiation-dominated regime.

    Science.gov (United States)

    Colgan, J; Abdallah, J; Faenov, A Ya; Pikuz, S A; Wagenaars, E; Booth, N; Culfa, O; Dance, R J; Evans, R G; Gray, R J; Kaempfer, T; Lancaster, K L; McKenna, P; Rossall, A L; Skobelev, I Yu; Schulze, K S; Uschmann, I; Zhidkov, A G; Woolsey, N C

    2013-03-22

    In high-spectral resolution experiments with the petawatt Vulcan laser, strong x-ray radiation of KK hollow atoms (atoms without n = 1 electrons) from thin Al foils was observed at pulse intensities of 3 × 10(20) W/cm(2). The observations of spectra from these exotic states of matter are supported by detailed kinetics calculations, and are consistent with a picture in which an intense polychromatic x-ray field, formed from Thomson scattering and bremsstrahlung in the electrostatic fields at the target surface, drives the KK hollow atom production. We estimate that this x-ray field has an intensity of >5 × 10(18) W/cm(2) and is in the 3 keV range.

  8. Investigation of high-temperature bright plasma X-ray sources produced in 5-MA X-pinch experiments.

    Science.gov (United States)

    Sinars, D B; McBride, R D; Pikuz, S A; Shelkovenko, T A; Wenger, D F; Cuneo, M E; Yu, E P; Chittenden, J P; Harding, E C; Hansen, S B; Peyton, B P; Ampleford, D J; Jennings, C A

    2012-10-12

    Using solid, machined X-pinch targets driven by currents rising from 0 to 5-6 MA in 60 ns, we observed bright spots of 5-9-keV continuum radiation from 5±2-μm diameter regions. The >6-keV radiation is emitted in about 0.4 ns, and the bright spots are roughly 75 times brighter than the bright spots measured at 1 MA. A total x-ray power of 10 TW peak and yields of 165±20 kJ were emitted from a 3-mm height. The 3-5-keV continuum radiation had a 50-90-GW peak power and 0.15-0.35-kJ yield. The continuum is plausibly from a 1275±75-eV blackbody or alternatively from a 3500±500-eV bremsstrahlung source.

  9. Response of monitoring instruments to high-energy photon radiation

    CERN Document Server

    Haridas, G; Pradhan, S D; Nayak, A R; Bhagwat, A M

    2000-01-01

    Response of commercially available monitoring instruments to high-energy photon radiation was studied under the stored beam condition of a few milliamperes in the storage ring of the Synchrotron Radiation Source, INDUS-I, at Centre for Advanced Technology (CAT), Indore. The storage ring has a circumference of 18.96 m, where electrons at 450 MeV are stored for a few hours, during which the emitted synchrotron radiation is exploited for scientific research and other applications. Radiation environment near storage ring has bremsstrahlung photons of various energies (maximum 450 MeV). A study has indicated underestimation of dose by conventional radiation monitoring instruments by a factor of 2-4. Response after transmission of photons through massive shield was also studied, which indicated spectral degradation and good response by the survey meters.

  10. Industrial applications of electron accelerators

    CERN Document Server

    Cleland, M R

    2006-01-01

    This paper addresses the industrial applications of electron accelerators for modifying the physical, chemical or biological properties of materials and commercial products by treatment with ionizing radiation. Many beneficial effects can be obtained with these methods, which are known as radiation processing. The earliest practical applications occurred during the 1950s, and the business of radiation processing has been expanding since that time. The most prevalent applications are the modification of many different plastic and rubber products and the sterilization of single-use medical devices. Emerging applications are the pasteurization and preservation of foods and the treatment of toxic industrial wastes. Industrial accelerators can now provide electron energies greater than 10 MeV and average beam powers as high as 700 kW. The availability of high-energy, high-power electron beams is stimulating interest in the use of X-rays (bremsstrahlung) as an alternative to gamma rays from radioactive nuclides.

  11. Cable SGEMP Code Validation Study

    Energy Technology Data Exchange (ETDEWEB)

    Ballard, William Parker [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Center for CA Weapons Systems Engineering

    2013-05-01

    This report compared data taken on the Modular Bremsstrahlung Simulator using copper jacketed (cujac) cables with calculations using the RHSD-RA Cable SGEMP analysis tool. The tool relies on CEPXS/ONBFP to perform radiation transport in a series of 1D slices through the cable, and then uses a Green function technique to evaluate the expected current drive on the center conductor. The data were obtained in 2003 as part of a Cabana verification and validation experiment using 1-D geometries, but were not evaluated until now. The agreement between data and model is not adequate unless gaps between the dielectric and outer conductor (ground) are assumed, and these gaps are large compared with what is believed to be in the actual cable.

  12. Modeling crossed-beam energy transfer for inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Marion, D. J. Y. [CEA, DAM, DIF, F-91297 Arpajon Cedex (France); Univ. Bordeaux, CEA, CNRS, CELIA, UMR5107, F-33400 Talence (France); Debayle, A., E-mail: arnaud.debayle@cea.fr; Masson-Laborde, P.-E.; Loiseau, P.; Casanova, M. [CEA, DAM, DIF, F-91297 Arpajon Cedex (France)

    2016-05-15

    We developed a numerical code that describes both the energy transfer occurring when two or more laser beams overlap in a weakly non-homogeneous plasma, and the beam energy losses associated with the electron-ion collisions. The numerical solutions are validated with both the exact analytical solutions in homogeneous plasmas, and with new approximate analytical solutions in non-homogeneous plasmas that include the aforementioned inverse bremsstrahlung effect. Comparisons with kinetic particle-in-cell simulations are satisfactory, provided the acoustic wave-breaking limit and the self-focusing regime are not reached. An application of the Cross-Beam Energy Transfer model is shown for a typical case of indirect-drive implosion in a gold hohlraum.

  13. A new double-foil soft x-ray array to measure T{sub e} on the MST reversed field pinch

    Energy Technology Data Exchange (ETDEWEB)

    McGarry, M. B.; Den Hartog, D. J.; Goetz, J. A. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Franz, P. [Consorzio RFX, Associazione Euratom-ENEA per la Fusione, 35127 Padova (Italy)

    2010-10-15

    A soft x-ray (SXR) diagnostic to measure electron temperature on the Madison Symmetric Torus using two complementary methods is presented. Both methods are based on the double-foil technique, which calculates electron temperature via the ratio of SXR bremsstrahlung emission from the plasma in two different energy ranges. The tomographic emissivity method applies the double-foil technique to a tomographic reconstruction of SXR emissivity, creating a two-dimensional map of temperature throughout the plasma. In contrast, the direct brightness method applies the double-foil technique directly to the measured brightness and generates vertical and horizontal radial profiles. Extensive modeling demonstrates advantages and limitations in both techniques. For example, although the emissivity technique provides a two-dimensional mapping of temperature, its reliance on multiple tomographic inversions introduces some artifacts into the results. On the other hand, the more direct brightness technique avoids these artifacts but is only able to provide a radial profile of electron temperature.

  14. Note: Effect of photodiode aluminum cathode frame on spectral sensitivity in the soft x-ray energy band

    Energy Technology Data Exchange (ETDEWEB)

    McGarry, M. B., E-mail: mbmcgarry@wisc.edu; Den Hartog, D. J.; Goetz, J. A.; Johnson, J. [Department of Physics, University of Wisconsin–Madison, Madison, Wisconsin 53706 (United States); Franz, P. [Consorzio RFX, Associazione Euratom-ENEA per la Fusione, Padova (Italy)

    2014-09-15

    Silicon photodiodes used for soft x-ray detection typically have a thin metal electrode partially covering the active area of the photodiode, which subtly alters the spectral sensitivity of the photodiode. As a specific example, AXUV4BST photodiodes from International Radiation Detectors have a 1.0 μm thick aluminum frame covering 19% of the active area of the photodiode, which attenuates the measured x-ray signal below ∼6 keV. This effect has a small systematic impact on the electron temperature calculated from measurements of soft x-ray bremsstrahlung emission from a high-temperature plasma. Although the systematic error introduced by the aluminum frame is only a few percent in typical experimental conditions on the Madison Symmetric Torus, it may be more significant for other instruments that use similar detectors.

  15. TLD determination of neutron dose contribution in medical linac

    Energy Technology Data Exchange (ETDEWEB)

    Cano, A.; Rivera, T.; Calderon A, J. A. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Azorin, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Villasenor N, L. F. [Hospital General de Mexico, Dr. Balmis No. 148, Col. Doctores, 06726 Mexico D. F. (Mexico); Vega C, H. R., E-mail: azorin@xanum.uam.m [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2011-02-15

    The increased use of Linacs with accelerating voltage higher than 10 MV in clinical radiotherapy is producing and increasing demand of accurate dosimetric measurements of the photon induced neutron contamination of the radiotherapy beams, due that the associated Bremsstrahlung X rays may produce neutrons as a result of subsequent photonuclear reactions with the different materials constituting the accelerator head. Thermal neutron fluences can be measured with TLD-600/TLD-700 pairs arranged in both a bare and a cadmium (Cd) foil covered methacry-late box. Neutron response of Tl dosemeters irradiated with two different neutron sources has been investigated. The shape of the glow curve of these TLDs after irradiation in a medical Linac and in a Pu Be neutron source has been studied to verify the contribution of neutrons to an additional dose to staff, patients and the general public, due to photonuclear reactions generating neutrons from medical Linacs. (Author)

  16. Search for the electric dipole excitations to the $3s_{1/2} \\otimes [2^{+}_{1} \\otimes 3^{-}_{1}]$ multiplet in $^{117}$Sn

    CERN Document Server

    Bryssinck, J; Bauwens, F; Beck, O; Belic, D; Von Brentano, P; De Frenne, D; Fransen, C; Herzberg, R D; Jacobs, E; Kneissl, U; Maser, H; Nord, A; Pietralla, N; Pitz, H H; Werner, V; Ponomarev, V Yu

    2000-01-01

    The odd-mass $^{117}$Sn nucleus was investigated in nuclear resonancefluorescence experiments up to an endpoint energy of the incident photonspectrum of 4.1 MeV at the bremsstrahlung facility of the Stuttgart University.More than 50 mainly hitherto unknown levels were found. From the measurement ofthe scattering cross sections model independent absolute electric dipoleexcitation strengths were extracted. The measured angular distributionssuggested the spins of 11 excited levels. Quasi-particle phonon modelcalculations including a complete configuration space were performed for thefirst time for a heavy odd-mass spherical nucleus. These calculations give aclear insight in the fragmentation and distribution of the $E1$, $M1$, and $E2$excitation strength in the low energy region. It is proven that the $1^{-}$component of the two-phonon $[2^{+}_{1} \\otimes 3^{-}_{1}]$ quintuplet built ontop of the $1/2^{+}$ ground state is strongly fragmented. The theoreticalcalculations are consistent with the experimental data.

  17. Double-polarization observable G in neutral-pion photoproduction off the proton

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, A.; Lang, M.; Afzal, F.; Beck, R.; Boese, S.; Funke, C.; Gottschall, M.; Gruener, M.; Hammann, C.; Hannappel, J.; Hartmann, J.; Hoffmeister, P.; Honisch, C.; Kaiser, D.; Kalinowsky, H.; Kalischewski, F.; Klassen, P.; Klempt, E.; Koop, K.; Kube, M.; Mahlberg, P.; Mueller, J.; Muellers, J.; Piontek, D.; Schmidt, C.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thoma, U.; Urban, M.; Pee, H. van; Walther, D.; Wendel, C.; Winnebeck, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Eberhardt, H.; Bantes, B.; Dutz, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Frommberger, F.; Goertz, S.; Hammann, D.; Hillert, W.; Jude, T.; Kammer, S.; Kleber, V.; Klein, F.; Reeve, S.; Runkel, S.; Schmieden, H. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Anisovich, A.V.; Bayadilov, D.; Nikonov, V.; Sarantsev, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bichow, M.; Meyer, W.; Reicherz, G. [Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik I, Bochum (Germany); Brinkmann, K.T.; Gutz, E. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen und Kernphysik, Bonn (Germany); Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Crede, V. [Florida State University, Department of Physics, Tallahassee, FL (United States); Dieterle, M.; Keshelashvili, I.; Krusche, B.; Witthauer, L. [Universitaet Basel, Institut fuer Physik, Basel (Switzerland); Friedrich, S.; Makonyi, K.; Metag, V.; Nanova, M. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Gridnev, A.; Lopatin, I. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Wilson, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Florida State University, Department of Physics, Tallahassee, FL (United States); Collaboration: The CBELSA/TAPS Collaboration

    2017-01-15

    This paper reports on a measurement of the double-polarization observable G in π{sup 0} photoproduction off the proton using the CBELSA/TAPS experiment at the ELSA accelerator in Bonn. The observable G is determined from reactions of linearly polarized photons with longitudinally polarized protons. The polarized photons are produced by bremsstrahlung off a diamond radiator of well-defined orientation. A frozen spin butanol target provides the polarized protons. The data cover the photon energy range from 617 to 1325 MeV and a wide angular range. The experimental results for G are compared to predictions by the Bonn-Gatchina (BnGa), Juelich-Bonn (JueBo), MAID and SAID partial wave analyses. Implications of the new data for the pion photoproduction multipoles are discussed. (orig.)

  18. Coherent Photoproduction of pi^+ from 3/^He

    Energy Technology Data Exchange (ETDEWEB)

    Rakhsha Nasseripour, Barry Berman

    2011-03-01

    We have measured the differential cross section for the $\\gamma$$^3$He$\\rightarrow \\pi^+ t$ reaction. This reaction was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B bremsstrahlung tagging system in the energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid $^3$He target. The differential cross sections for the $\\gamma$$^3$He$\\rightarrow \\pi^+ t$ reaction were measured as a function of photon-beam energy and pion-scattering angle. Theoretical predictions to date cannot explain the large cross sections except at backward angles, showing that additional components must be added to the model.

  19. ILU industrial electron accelerators for medical-product sterilization and food treatment

    Science.gov (United States)

    Bezuglov, V. V.; Bryazgin, A. A.; Vlasov, A. Yu.; Voronin, L. A.; Panfilov, A. D.; Radchenko, V. M.; Tkachenko, V. O.; Shtarklev, E. A.

    2016-12-01

    Pulse linear electron accelerators of the ILU type have been developed and produced by the Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, for more than 30 years. Their distinctive features are simplicity of design, convenience in operation, and reliability during long work under conditions of industrial production. ILU accelerators have a range of energy of 0.7-10 MeV at a power of accelerated beam of up to 100 kW and they are optimally suitable for use as universal sterilizing complexes. The scientific novelty of these accelerators consists of their capability to work both in the electron-treatment mode of production and in the bremsstrahlung generation mode, which has high penetrating power.

  20. A cesium plasma TELEC device for conversion of laser radiation to electric power

    Science.gov (United States)

    Britt, E. J.; Rasor, N. S.; Lee, G.; Billman, K. W.

    1978-01-01

    Tests of the thermoelectronic laser energy converter (TELEC) concept are reported. This device has been devised as a means to convert high-average-power laser radiation into electrical energy, a crucial element in any space laser power transmission scheme using the available high-power/efficiency infrared lasers. Theoretical calculations, based upon inverse bremsstrahlung absorption in a cesium plasma, indicate internal conversion efficiency up to 50% with an overall system efficiency of 42%. The experiments reported were made with a test cell designed to confirm the theoretical model rather than demonstrate efficiency; 10.6-micron laser-beam absorption was limited to about 0.001 of the incident beam by the short absorption region. Nevertheless, confirmatory results were obtained, and the conversion of absorbed radiation to electric power is estimated to be near 10%.

  1. Dynamics of the microstructure of current channels and the generation of high-energy electrons in nanosecond discharges in air

    Energy Technology Data Exchange (ETDEWEB)

    Karelin, V. I.; Trenkin, A. A., E-mail: trenkin@ntc.vniief.ru; Fedoseev, I. G. [Russian Federal Nuclear Center VNIIEF (Russian Federation)

    2015-12-15

    The results of the three-dimensional numerical simulation of the dynamics of the microstructure of high-voltage nanosecond discharges in air at atmospheric pressure are presented. It is established that the fast (at a time of ≈10 ns) broadening and significant decrease in the gas concentration in the microchannels occur as a result of the ohmic heating of microchannels with the diameter of 1–30 μm. It was shown that the broadening of microchannels in a nanosecond diffusive discharge provides an increase in the ratio of the electric field strength to the gas concentration in microchannels to values sufficient for the generation highenergy electron beams and X-ray bremsstrahlung in them. Features of the dynamics of the system of microchannels and its effect on the efficiency of the generation of high-energy electrons in discharges developing in the microstructuring regime of the current channels are considered.

  2. Relativistic nonlinear electrodynamics the QED vacuum and matter in super-strong radiation fields

    CERN Document Server

    Avetissian, Hamlet K

    2016-01-01

    This revised edition of the author’s classic 2006 text offers a comprehensively updated review of the field of relativistic nonlinear electrodynamics. It explores the interaction of strong and super-strong electromagnetic/laser radiation with the electromagnetic quantum vacuum and diverse types of matter – including free charged particles and antiparticles, acceleration beams, plasma and plasmous media.  The appearance of laser sources of relativistic and ultra-relativistic intensities over the last decade has stimulated investigation of a large class of processes under such super-strong radiation fields. Revisions for this second edition reflect these developments and the book includes new chapters on Bremsstrahlung and nonlinear absorption of superintense radiation in plasmas, the nonlinear interaction of relativistic atoms with intense laser radiation, nonlinear interaction of strong laser radiation with Graphene, and relativistic nonlinear phenomena in solid-plasma targets under supershort laser pul...

  3. Rotational character of the 12C spectrum investigated through inelastic cross sections via photon emission

    Directory of Open Access Journals (Sweden)

    Garrido E.

    2016-01-01

    Full Text Available In this work the bremsstrahlung and photon dissociation cross sections for transitions between 0+, 2+, and 4+ states in 12C are computed. The nucleus is described within the three-alpha model, and the wave functions are computed by means of the hyperspherical adiabatic expansion method. The continuum states are discretized by imposing a box boundary condition. The transition strengths are obtained from the cross sections, and compared to schematic rotational model predictions. The computed results strongly suggest that the two lowest bands are made, respectively, by the states with angular momentum and parity {01+, 21+, 42+} and {02+, 22+, 41+}. The transitions between the states in the first band are consistent with the rotational pattern corresponding to three alphas in an equilateral triangular structure. For the second band, the transitions are also consistent with a rotational pattern, but with the three alphas in an aligned distribution.

  4. Exotic sources of x-rays for iodine K-edge angiography

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.

    1993-08-01

    Digital Subtractive Angiography (DSA) has been performed to image human coronary arteries using wiggler radiation from electron storage rings. The significant medical promise of this procedure motivates the development of smaller and less costly x-ray sources. Several exotic sources are candidates for consideration, using effects such as Cherenkov, channeling, coherent bremsstrahlung, laser backscattering, microundulator, parametric, Smith-Purcell, and transition radiation. In this work we present an analysis of these effects as possible sources of intense x-rays at the iodine K-edge at 33.169 key. The criteria we use are energy, efficiency, flux, optical properties, and technical realizability. For each of the techniques, we find that they suffer either from low flux, a low energy cutoff, target materials heating, too high electron beam energy requirement, optical mismatch to angiography, or a combination of these. We conclude that the foreseeable state-of-the-art favors a compact storage ring design.

  5. Note: Effect of photodiode aluminum cathode frame on spectral sensitivity in the soft x-ray energy band.

    Science.gov (United States)

    McGarry, M B; Franz, P; Den Hartog, D J; Goetz, J A; Johnson, J

    2014-09-01

    Silicon photodiodes used for soft x-ray detection typically have a thin metal electrode partially covering the active area of the photodiode, which subtly alters the spectral sensitivity of the photodiode. As a specific example, AXUV4BST photodiodes from International Radiation Detectors have a 1.0 μm thick aluminum frame covering 19% of the active area of the photodiode, which attenuates the measured x-ray signal below ~6 keV. This effect has a small systematic impact on the electron temperature calculated from measurements of soft x-ray bremsstrahlung emission from a high-temperature plasma. Although the systematic error introduced by the aluminum frame is only a few percent in typical experimental conditions on the Madison Symmetric Torus, it may be more significant for other instruments that use similar detectors.

  6. A measurement of the LPM effect

    Energy Technology Data Exchange (ETDEWEB)

    Klein, S.R. [California Univ., Santa Cruz, CA (United States). Inst. for Particle Physics; Anthony, P. [Lawrence Livermore National Lab., CA (United States)]|[Stanford Linear Accelerator Center, Menlo Park, CA (United States); Becker-Szendy, R. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

    1993-11-01

    We have performed an experiment to measure accurately the Landau-Pomeranchuk-Migdal (LPM) effect in the production of 5 to 500 MeV photons due to bremsstrahlung of 8 and 25 GeV electron beams traversing thin (2 to 6% X₀) targets of varying densities. Our measurements confirm that the LPM effect exists and that the Migdal calculations are accurate. We see that, for thin targets, LPM suppression disappears leaving a Bethe-Heitler spectrum, as predicted by theory. For intermediate target thicknesses, we lack an acceptable theory, but have measured energy spectra for targets of differing thickness. We have also measured the production rate of 500 keV to 5 MeV photons at the same electron energies, to study dielectric suppression. We see qualitative agreement with the theory of Ter-Mikaelian; more work is needed before we can make quantitative comparisons.

  7. Measurement of the luminosity in the ZEUS experiment at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, L.; Bold, T. [AGH Univ. of Science and Technology, Cracow (Poland); Andruszkow, J. [Polish Academy of Sciences, Cracow (Poland). Inst. of Nuclear Physics] [and others

    2013-06-15

    The luminosity in the ZEUS detector was measured using photons from electron bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher luminosity. At the same time the luminosity-measuring system of the ZEUS experiment was modified to tackle the expected higher photon rate and synchrotron radiation. The existing lead-scintillator calorimeter was equipped with radiation hard scintillator tiles and shielded against synchrotron radiation. In addition, a magnetic spectrometer was installed to measure the luminosity independently using photons converted in the beam-pipe exit window. The redundancy provided a reliable and robust luminosity determination with a systematic uncertainty of 1.7%. The experimental setup, the techniques used for luminosity determination and the estimate of the systematic uncertainty are reported.

  8. Beam-Helicity Asymmetries in Double Pion Photoproduction off the Proton

    CERN Document Server

    Krambrich, D; Fix, A; Roca, L; Aguar, P; Ahrens, J; Annand, J R M; Arends, H J; Beck, R; Bekrenev, V; Boillat, B; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Codling, R; Downie, E J; Dexler, P; Glazier, D I; Grabmayr, P; Gregor, R; Heid, E; Hornidge, D; Jahn, O; Kashevarov, V L; Knezevic, A; Kondratiev, R; Korolija, M; Kotulla, M; Krusche, B; Kulbardis, A; Lang, M; Lisin, V; Livingston, K; Lugert, S; MacGregor, I J D; Manley, D M; Martínez, M; McGeorge, J C; Mekterovic, D; Metag, V; Nefkens, B M K; Nikolaev, A; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S N; Price, J W; Rosner, G; Rost, M; Rostomyan, T; Schumann, S; Sober, D; Starostin, A; Supek, I; Tarbert, C M; Thomas, A; Unverzagt, M; Walcher, Th; Watts, D P

    2009-01-01

    Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz in the three isospin channels $\\vec{\\gamma}p\\to \\pi^{+}\\pi^0n$, $\\vec{\\gamma}p\\to \\pi^{0}\\pi^0p$ and $\\vec{\\gamma}p\\to \\pi^{+}\\pi^{-}p$ . The circularly polarized photons, produced from bremsstrahlung of longitudinally polarized electrons, were tagged with the Glasgow magnetic spectrometer. Charged pions and the decay photons of $\\pi^0$ mesons were detected in a $~4\\pi$ electromagnetic calorimeter which combined the Crystal Ball detector with the TAPS detector. The precisely measured asymmetries are very sensitive to details of the production processes and are thus key observables in the modeling of the reaction dynamics.

  9. Geant4 electromagnetic physics for high statistic simulation of LHC experiments

    CERN Document Server

    Allison, J; Bagulya, A; Champion, C; Elles, S; Garay, F; Grichine, V; Howard, A; Incerti, S; Ivanchenko, V; Jacquemier, J; Maire, M; Mantero, A; Nieminen, P; Pandola, L; Santin, G; Sawkey, D; Schalicke, A; Urban, L

    2012-01-01

    An overview of the current status of electromagnetic physics (EM) of the Geant4 toolkit is presented. Recent improvements are focused on the performance of large scale production for LHC and on the precision of simulation results over a wide energy range. Significant efforts have been made to improve the accuracy without compromising of CPU speed for EM particle transport. New biasing options have been introduced, which are applicable to any EM process. These include algorithms to enhance and suppress processes, force interactions or splitting of secondary particles. It is shown that the performance of the EM sub-package is improved. We will report extensions of the testing suite allowing high statistics validation of EM physics. It includes validation of multiple scattering, bremsstrahlung and other models. Cross checks between standard and low-energy EM models have been performed using evaluated data libraries and reference benchmark results.

  10. Phenomenology of collinear photon emission from quark-gluon plasma in AA collisions

    Science.gov (United States)

    Zakharov, B. G.

    2017-09-01

    We study the role of running coupling and the effect of variation of the thermal quark mass on contribution of the collinear bremsstrahlung and annihilation to photon emission in AA collisions in a scheme similar to that used in our previous jet quenching analyses. We find that for a scenario with the thermal quark mass m q ˜ 50-100 MeV contribution of the higher order collinear processes summed with the 2 → 2 processes can explain a considerable part (˜ 50 %) of the experimental photon spectrum at k T ˜ 2-3 GeV for Au+Au collisions at √s = 0.2 TeV. But for m q = 300 MeV and for the thermal quark mass predicted by the HTL scheme the theoretical predictions underestimate considerably the experimental spectrum.

  11. Exotic Hybrid Meson Spectroscopy with the GlueX detector at JLab

    Directory of Open Access Journals (Sweden)

    Lawrence David

    2014-03-01

    Full Text Available The GlueX experiment[1] is scheduled to begin taking data in 2015. The goal is to discover evidence for the existence of exotic hybrid mesons and to map out their spectrum in the light quark sector. Recent theoretical developments using Lattice QCD [2] predict exotic hybrid states in a mass range accessible using the newly upgraded 12GeV electron accelerator at Jefferson Lab. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. The experiment will use 9 GeV linearly polarized photons produced via coherent Bremsstrahlung to produce the exotic hybrids. The decay products will be detected in the solenoid-based GlueX detector currently under construction at Jefferson Lab. The status of the GlueX experiment including detector parameters will be presented along with theoretical motivation for the experiment.

  12. The Heavy Photon Search experiment at Jefferson Laboratory

    Directory of Open Access Journals (Sweden)

    De Napoli Marzio

    2015-01-01

    Full Text Available Many beyond Standard Model theories predict a new massive gauge boson, aka “dark” or “heavy photon”, directly coupling to hidden sector particles with dark charge. The heavy photon is expected to mix with the Standard Model photon through kinetic mixing and therefore couple weakly to normal charge. The Heavy Photon Search (HPS experiment will search for the heavy photon at the Thomas Jefferson National Accelerator Facility (JLab, in the mass range 20-1000 MeV/c2 and coupling to electric charge ϵ2 = α′/α in the range 10−5 to 10−10. HPS will look for the e+e− decay channel of heavy photons radiated by electron Bremsstrahlung, employing both invariant mass search and detached vertexing techniques. The experiment employs a compact forward spectrometer comprising silicon microstrip detectors for vertexing and tracking and an electromagnetic calorimeter for particle identification and triggering.

  13. Temporary acceleration of electrons while inside an intense electromagnetic pulse

    Directory of Open Access Journals (Sweden)

    Kirk T. McDonald

    1999-12-01

    Full Text Available A free electron can temporarily gain a very significant amount of energy if it is overrun by an intense electromagnetic wave. In principle, this process would permit large enhancements in the center-of-mass energy of electron-electron, electron-positron, and electron-photon interactions if these take place in the presence of an intense laser beam. Practical considerations severely limit the utility of this concept for contemporary lasers incident on relativistic electrons. A more accessible laboratory phenomenon is electron-positron production via an intense laser beam incident on a gas. Intense electromagnetic pulses of astrophysical origin can lead to very energetic photons via bremsstrahlung of temporarily accelerated electrons.

  14. Modelling of radiation impact on ITER Beryllium wall

    Science.gov (United States)

    Landman, I. S.; Janeschitz, G.

    2009-04-01

    In the ITER H-Mode confinement regime, edge localized instabilities (ELMs) will perturb the discharge. Plasma lost after each ELM moves along magnetic field lines and impacts on divertor armour, causing plasma contamination by back propagating eroded carbon or tungsten. These impurities produce enhanced radiation flux distributed mainly over the beryllium main chamber wall. The simulation of the complicated processes involved are subject of the integrated tokamak code TOKES that is currently under development. This work describes the new TOKES model for radiation transport through confined plasma. Equations for level populations of the multi-fluid plasma species and the propagation of different kinds of radiation (resonance, recombination and bremsstrahlung photons) are implemented. First simulation results without account of resonance lines are presented.

  15. Laser fusion implosion and plasma interaction experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstrom, H.G.

    1977-08-01

    Results related to the propagation, absorption and scattering of laser light by both spherical and planar targets are described. The absorption measurements indicate that for intensities of interest, inverse bremsstrahlung is not the dominant absorption mechanism. The laser light scattered by the plasma is polarization dependent and provides evidence that Brillouin scattering and resonance absorption are operative. Special diagnostics have been designed and experiments have been performed to elucidate the nature of these two processes. Implosion results on glass microshell targets filled with DT gas are also summarized. These experiments are for targets intentionally operated in the portion of parameter space characteristic of exploding pusher events. Experiments have been performed over a yield range from 0 to 10/sup 9/ neutrons per event. It is shown how this data can be normalized with a simple scaling law.

  16. Gravitational Radiation from Massless Particle Collisions

    CERN Document Server

    Gruzinov, Andrei

    2016-05-17

    We compute classical gravitational bremsstrahlung from the gravitational scattering of two massless particles at leading order in the (center of mass) deflection angle $\\theta\\sim 8 G E/b \\ll 1$. The calculation, although non-perturbative in the gravitational constant, is surprisingly simple and yields explicit formulae --in terms of multidimensional integrals-- for the frequency and angular distribution of the radiation. In the range $ b^{-1} (GE)^{-1}$ the radiation is confined to cones of angular size of order $\\theta (GE\\omega)^{-1/2}$ resulting in a scale-invariant ($d\\omega/\\omega$) spectrum. The total efficiency in GW production is dominated by this "high frequency" region and is formally logarithmically divergent in the UV. If the spectrum is cutoff at the limit of validity of our approximations ($ GE \\omega \\sim \\theta^{-2}$), the fraction of incoming energy radiated away turns out to be $\\frac{1}{\\pi} \\theta ^2 \\log \\theta^{-2}$ at leading logarithmic accuracy.

  17. Atomic spectroscopy and radiative processes

    CERN Document Server

    Landi Degl'Innocenti, Egidio

    2014-01-01

    This book describes the basic physical principles of atomic spectroscopy and the absorption and emission of radiation in astrophysical and laboratory plasmas. It summarizes the basics of electromagnetism and thermodynamics and then describes in detail the theory of atomic spectra for complex atoms, with emphasis on astrophysical applications. Both equilibrium and non-equilibrium phenomena in plasmas are considered. The interaction between radiation and matter is described, together with various types of radiation (e.g., cyclotron, synchrotron, bremsstrahlung, Compton). The basic theory of polarization is explained, as is the theory of radiative transfer for astrophysical applications. Atomic Spectroscopy and Radiative Processes bridges the gap between basic books on atomic spectroscopy and the very specialized publications for the advanced researcher: it will provide under- and postgraduates with a clear in-depth description of theoretical aspects, supported by practical examples of applications.

  18. Lost Muon Study for the Muon G-2 Experiment at Fermilab*

    Energy Technology Data Exchange (ETDEWEB)

    Ganguly, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Crnkovic, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Morse, W. M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-05-19

    The Fermilab Muon g-2 Experiment has a goal of measuring the muon anomalous magnetic moment to a precision of 140 ppb - a fourfold improvement over the 540 ppb precision obtained by the BNL Muon g-2 Experiment. Some muons in the storage ring will interact with material and undergo bremsstrahlung, emitting radiation and loosing energy. These so called lost muons will curl in towards the center of the ring and be lost, but some of them will be detected by the calorimeters. A systematic error will arise if the lost muons have a different average spin phase than the stored muons. Algorithms are being developed to estimate the relative number of lost muons, so as to optimize the stored muon beam. This study presents initial testing of algorithms that can be used to estimate the lost muons by using either double or triple detection coincidences in the calorimeters.

  19. Heavy Nuclei Photofission at Intermediate Energies

    CERN Document Server

    Deppman, A; Guimaraes, V; Demekhina, N A; Karapetyan, G S

    2013-01-01

    In the present work the yields of fission fragments, from Bremsstrahlung induced fission of 232Th, 238U targets, were reproduced by CRISP model calculations, to which a multimodal fission option had been added. An extension of the calculation to the properties of the fission products is presented. Dividing the fissioning nuclei according to their fissionability, an approach which accounts for the contribution of symmetric and asymmetric fission is introduced. It allows to calculate the main parameters of the fission fragment charge distribution: the most probable charge for a given fission product mass chain and the width parameter. Furthermore, it reproduces the features of fragment mass distribution, and evaluates the fissility of fissioning nuclei in photon-induced fission. A comparison between the results of this calculation and experimental data is accomplished.

  20. Generation of intense X-radiation and high-energy-density matter by laser-accelerated electrons; Erzeugung von intensiver Roentgenstrahlung und Materie hoher Energiedichte durch Laserbeschleunigte Elektronen

    Energy Technology Data Exchange (ETDEWEB)

    Schoenlein, Andreas

    2015-07-01

    Aim of this thesis was to study the processes of the interaction between highly intense short-pulse laser and matter. The focus lied thereby on the generation of intense X-radiation and warm dense matter. The studies performed for this thesis comprehend thereby the influence of laser parameters like energy, pulse length, focus size, and intensity as well as the influence of the target geometry on the interaction and generation of high-energy-density matter. In this thesis for this two selected experiments are presented. First a silver foil was used as target, in order to study the generation of radiation at 21 keV. Both bremsstrahlung and characteristic X-radiation were used in order to characterize the interaction. For the second experiment freely standing titanium wires were used as target. Hereby the focus lied on the characterization of the heated matter.

  1. Specific Treatments of Diane for Radiographic Applications

    Energy Technology Data Exchange (ETDEWEB)

    Toccoli, C.; Caillaud, M.; Demoulins, M.; Laithier, A.; Lemaire, S.; Ribes, J. C.; Riz, D. [CEA Bruyeres le Chatel, DIF, 91 (France)

    2009-12-15

    From a computing standpoint, flash X-ray radiography is much more time-consuming than traditional X-ray applications, and despite the constant increase of computing resources, methods to reduce the calculation time while preserving accuracy are highly needed. At the Commissariat a l'Energie Atomique, DIANE is the code devoted to flash X-ray calculations. After a brief description of the general features of DIANE, two selected methods implemented in DIANE to provide fast calculations are described. One concerns Bremsstrahlung X-ray creation without electron transport electrons: the SSB model. The quality of this model is assessed within the framework of flash X-ray applications on two test problems with a fully photon-electron transport performed with MCNP5. The other focuses on particle tracking and Woodcock tracking. The performance of tracking within large meshes is evaluated. (authors)

  2. Experimental measurements of the radiation hazards associated with manned space flights.

    Science.gov (United States)

    Clark, B C; Adams, D A

    1965-01-01

    Tissue-equivalent ionization chambers of special design have been flown on U.S. satellites to determine dose-rate levels in space. A chamber shielded by 4.7 g/cm2 measured doses from energetic protons in the inner Van Allen belt and bremsstrahlung radiation produced by relativistic electrons from the artificial radiation belt formed in July 1962. In November 1962, the maximum dose-rate in space for this shield was 30 rad/hr. Behind 0.4 g/cm2 shielding, the dose-rate peak was 20000 rad/hr. These doses have been determined to be due to artificial electrons in most regions of space, masking the dose arising from energetic protons.

  3. Investigation of123I production using electron accelerator.

    Science.gov (United States)

    Avetisyan, Albert; Avagyan, Robert; Dallakyan, Ruben; Avdalyan, Gohar; Dobrovolsky, Nikolay; Gavalyan, Vasak; Kerobyan, Ivetta; Harutyunyan, Gevorg

    2017-04-01

    The possibility of 123 I isotope production with the help of the high-intensity bremsstrahlung photons produced by the electron beam of the LUE50 linear electron accelerator at the A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute [YerPhI]) is considered. The production method has been established and shown to be successful. The 124 Xe(γ,n) 123 Xe→ 123 I nuclear reaction has been investigated and the cross-section was calculated by nuclear codes TALYS 1.6 and EMPIRE 3.2. The optimum parameter of the thickness of the target was determined by GEANT4 code. For the normalized yield of 123 I, the value of 143Bq/(mg·μA·h) has been achieved. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Modeling and numerical analysis of a magneto-inertial fusion concept with the target created through FRC merging

    Science.gov (United States)

    Li, Chenguang; Yang, Xianjun

    2016-10-01

    The Magnetized Plasma Fusion Reactor concept is proposed as a magneto-inertial fusion approach based on the target plasma created through the collision merging of two oppositely translating field reversed configuration plasmas, which is then compressed by the imploding liner driven by the pulsed-power driver. The target creation process is described by a two-dimensional magnetohydrodynamics model, resulting in the typical target parameters. The implosion process and the fusion reaction are modeled by a simple zero-dimensional model, taking into account the alpha particle heating and the bremsstrahlung radiation loss. The compression on the target can be 2D cylindrical or 2.4D with the additive axial contraction taken into account. The dynamics of the liner compression and fusion burning are simulated and the optimum fusion gain and the associated target parameters are predicted. The scientific breakeven could be achieved at the optimized conditions.

  5. Study of TeV Neutrinos with Upward Showering Muons in Super-Kamiokande

    CERN Document Server

    Desai, S

    2007-01-01

    A subset of neutrino-induced upward through-going muons in the Super-Kamiokande detector consists of high energy muons which lose energy through radiative processes such as bremsstrahlung, e^{+} e^{-} pair production and photonuclear interactions. These ``upward showering muons'' comprise an event sample whose mean parent neutrino energy is approximately 1 TeV. We show that the zenith angle distribution of upward showering muons is consistent with negligible distortion due to neutrino oscillations, as expected of such a high-energy neutrino sample. We present astronomical searches using these high energy events, such as those from WIMP annihilations in the Sun, Earth and Galactic Center, some suspected point sources, as well as searches for diffuse flux from the interstellar medium.

  6. A pre-identification for electron reconstruction in the CMS particle-flow algorithm

    CERN Document Server

    Pioppi, Michele

    2008-01-01

    In the CMS software, a dedicated electron track reconstruction algorithm, based on a Gaussian Sum Filter (GSF), is used. This algorithm is able to follow an electron along its complete path up to the electromagnetic calorimeter, even in the case of a large amount of Bremsstrahlung emission. Because of the significant CPU consumption of this algorithm, it can, however, only be run on a limited number of candidates. The standard GSF electron track reconstruction is triggered by the presence of high energy isolated electromagnetic clusters, but it is not suited for electrons in jets (usually soft and not isolated). A pre-identification algorithm based on both the tracker and the calorimeter, was therefore recently developed. It allows electron tracks within jets to be efficiently reconstructed even for small electron transverse momentum. This algorithm as well as its performance in terms of efficiency, mis-identification probability are presented.

  7. High quality electron bunch generation with CO2-laser plasma accelerator

    CERN Document Server

    Zhang, L G; Xu, J C; Ji, L L; Zhang, X M; Wang, W P; Zhao, X Y; Yi, L Q; Yu, Y H; Shi, Y; Xu, T J; Xu, Z Z

    2014-01-01

    CO2 laser-driven electron acceleration is demonstrated with particle-in-cell simulation in low-density plasma. An intense CO2 laser pulse with long wavelength excites wakefield. The bubble behind it has a broad space to sustain a large amount of electrons before reaching its charge saturation limit. A transversely propagating inject pulse is used to induce and control the ambient electron injection. The accelerated electron bunch with total charge up to 10 nC and the average charge per energy interval of more than 0.6 nC/MeV are obtained. Plasma-based electron acceleration driven by intense CO2 laser provides a new potential way to generate high-charge electron bunch with low energy spread, which has broad applications, especially for X-ray generation by table-top FEL and bremsstrahlung.

  8. Digital Mammography: Improvements in Breast Cancer Diagnostic

    Science.gov (United States)

    Montaño Zetina, Luis Manuel

    2006-01-01

    X-ray mammography is the most sensitive imaging technique for early detection of breast cancer (diagnostics). It is performed by a radiological system equipped with a rotating molybdenum (Mo) anode tube with an additional Mo filter. In the production of X-ray, bremsstrahlung photons produce an intense diffuse radiation, affecting the contrast between normal and cancerous tissue. So it is known that a good mammographic imaging can help to detect cancer in the first stages avoiding surgery, amputation or even death. In the last years there has been some developments in new imaging techniques to improve the contrast spatial resolution between different tissues: digital imaging, or the so call digital mammography. Digital mammographic imaging is considered an improvement in the prevention of breast cancer due to the advantages it offers.

  9. Low-energy electron impact cross-sections and rate constants of NH_2

    Science.gov (United States)

    Bharadvaja, Anand; Kaur, Savinder; Baluja, K. L.

    2017-08-01

    This systematic study reports various electron impact cross-sections, rate constants and transport properties of NH_2 radical in the low-energy limit. The collision study is based on R-matrix formalism and involves the use of various scattering models employing different active spaces. Both electron excited inelastic cross-sections and resonances are found influenced by correlation and polarization effects. The non-relativistic molecular bremsstrahlung radiation cross-section for soft photons, binary encounter Bethe model-based ionization cross-sections and a few molecular properties of the target radical are also reported. The present calculations are found to be in agreement with the available results. This theoretical study provides a pathway to understand collision dynamics and generates data required in various fields of applied physics.

  10. Reduction of collisional-radiative models for laser-produced argon plasmas

    Science.gov (United States)

    Abrantes, Richard June; Karagozian, Ann; Le, Hai

    2016-10-01

    The formation of a laser-induced plasma involves a variety of physical phenomena stemming from the laser-plasma interaction. A thorough understanding of these processes encourages improvement and innovation for many applications. In this work, we aim to computationally reduce a previously-developed collisional-radiative (CR) model constructed from the LANL database, which includes all of the relevant collisional and radiative processes for all the ionic stages of argon. The laser is coupled to the plasma via multiphoton ionization and inverse Bremsstrahlung, processes important for electron production and heating. The use of the CR model allows us to identify dominant mechanisms responsible for initial breakdown of the gas and thermal equilibriation processes. The results are compared with experimental data from laser-induced breakdown experiments. Research supported by the AFOSR.

  11. The τ leptons theory and experimental data: Monte Carlo, fits, software and systematic errors

    Science.gov (United States)

    Was, Z.

    2015-03-01

    Status of τ lepton decay Monte Carlo generator TAUOLA is reviewed. Recent efforts on development of new hadronic currents are presented. Multitude new channels for anomalous τ decay modes and parameterization based on defaults used by BaBar collaboration are introduced. Also parameterization based on theoretical considerations are presented as an alternative. Lesson from comparison and fits to the BaBar and Belle data is recalled. It was found that as in the past, in particular at a time of comparisons with CLEO and ALEPH data, proper fitting, to as detailed as possible representation of the experimental data, is essential for appropriate developments of models of τ decays. In the later part of the presentation, use of the TAUOLA program for phenomenology of W, Z, H decays at LHC is adressed. Some new results, relevant for QED bremsstrahlung in such decays are presented as well.

  12. Effects of fissioning nuclei distributions on fragment mass distributions for high energy fission

    Directory of Open Access Journals (Sweden)

    Rossi P C R

    2012-02-01

    Full Text Available We study the effects of fissioning nuclei mass- and energy-distributions on the formation of fragments for fission induced by high energy probes. A Monte Carlo code called CRISP was used for obtaining mass distributions and spectra of the fissioning nuclei for reactions induced by 660 MeV protons on 241Am and on 239Np, by 500 MeV protons on 208Pb, and by Bremsstrahlung photons with end-point energies at 50 MeV and 3500 MeV on 238U. The results show that even at high excitation energies, asymmetric fission may still contribute significantly to the fission cross section of actinide nuclei, while it is the dominante mode in the case of lead. However, more precise data for high energy fission on actinide are necessary in order to allow definite conclusions.

  13. Measurement of the Slope Parameter $\\alpha$ for the $\\eta\\to 3\\pi^0$ decay with the Crystal Ball at MAMI-C

    CERN Document Server

    Prakhov, S; Aguar, P; Akasoy, L K; Annand, J R M; Arends, H J; Bartolome, P A; Bantawa, K; Beck, R; Bekrenev, V; Berghauser, H; Boillat, B; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Codling, R F B; Downie, E J; Drexler, P; Filkov, L V; Glazier, D I; Gregor, R; Heid, E; Hornidge, D; Jahn, O; Jude, T C; Kashevarov, V L; Kellie, J D; Kondratiev, R; Korolija, M; Kotulla, M; Koulbardis, A; Krambrich, D; Kruglov, S; Krusche, B; Lang, M; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Manley, D M; Martínez, M; McGeorge, J C; McNicoll, E F; Mekterovic, D; Metag, V; Micanovic, S; Nikolaev, A; Novotny, R; Ostrick, M; Otte, P B; Pedroni, P; Pheron, F; Polonski, A; Robinson, J; Rosner, G; Rost, M; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D I; Starostin, A; Suarez, I M; Supek, I; Tarbert, C M; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P; Zamboni, I; Zehr, F

    2008-01-01

    The dynamics of the $\\eta\\to 3\\pi^0$ decay have been studied with the Crystal Ball multiphoton spectrometer and the TAPS calorimeter. Bremsstrahlung photons produced by the 1.5 GeV electron beam of the Mainz microtron MAMI-C and tagged by the Glasgow photon spectrometer were used for $\\eta$-meson production. The analysis of $3 \\times 10^6$ $\\gamma p \\to \\eta p \\to 3\\pi^0 p \\to 6\\gamma p$ events yields the value $\\alpha=-0.032\\pm0.003$ for the $\\eta\\to 3\\pi^0$ slope parameter, which agrees with the majority of recent experimental results and has the smallest uncertainty. The $\\pi^0\\pi^0$ invariant-mass spectrum was investigated for the occurrence of a cusp-like structure in the vicinity of the $\\pi^+\\pi^-$ threshold. The observed effect is small and does not affect our measured value for the slope parameter.

  14. Neutron total cross section measurements with the {sup 6}Li-ZnS(Ag) scintillator (BC702) employing a neutron and noise separation technique

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sung Gyun; Kye, Yong Uk; Cho, Moo Hyun [Pohang University of Science and Technology, Pohang (Korea, Republic of); Namkung, Won [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Kim, Gui Nyun [Kyungpook National University, Daegu (Korea, Republic of); Lee, Man Woo; Kang, Yeong Rok [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-05-15

    The neutron total cross-section of natural Dy has been measured in the energy region from 0.01 to 100 eV by using the neutron time-of-flight method at Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled Ta target with a water moderator, and a timeof-flight path with an 11-m length. A {sup 6}Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.5 cm has been used as a neutron detector, and a metallic Dy plate has been used for the neutron transmission measurement. The background level has been determined by using notch filters of Co, Ta, and Cd sheets. In order to reduce the gamma rays from Bremsstrahlung and from neutron capture, we have employed a neutron-gamma separation system based on their different pulse shapes.

  15. First Measurement of the Quark-to-Photon Fragmentation Function

    CERN Document Server

    Thompson, J

    1995-01-01

    Earlier measurements at LEP of isolated hard photons in hadronic $Z$ decays attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon production {\\em inside} hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energy $z\\geq 0.7$. After statistical subtraction of non-prompt photons, the quark- to-photon fragmentation function, $D(z)$, is extracted directly from the measured prompt production rate. By taking into account the perturbative contributions to $D(z)$ obtained from an $\\cal{O}(\\alpha \\alpha_S)$ QCD calculation, the unknown non-perturbative component of $D(z)$ is determined at high $z$. This measurement is compared with an earlier theoretical parametrisation widely used to determine the level of quark bremsstrahlung present in prompt photon production at the hadron colliders.

  16. AN ENERGY-CONSERVING, PARTICLE-DOMINATED, TIME-DEPENDENT MODEL OF 3C 58 AND ITS OBSERVABILITY AT HIGH ENERGIES

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Diego F.; Martin Rodriguez, Jonatan [Institute of Space Sciences (IEEC-CSIC), Campus UAB, Torre C5, 2a planta, E-08193 Barcelona (Spain); Cillis, Analia N. [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67-Suc. 28 (C1428ZAA), Buenos Aires (Argentina)

    2013-01-20

    We present a time-dependent spectral model of the nebula 3C 58 and compare it with available data. The model is for a leptonic nebula in which particles are subject to synchrotron, inverse Compton, self-synchrotron Compton, adiabatic, and bremsstrahlung processes. We find that 3C 58 is compatible with being a particle-dominated nebula, with a magnetic field of 35 {mu}G. A broken power-law injection fits well the multi-frequency data, with a break energy at about 40 GeV. We find that 3C 58 is not expected to appear in VERITAS or MAGIC II, unless the local IR background is a factor of {approx}20 off Galactic models' averages. For cases in which the cosmic microwave background dominates the inverse Compton contribution, we find that 3C 58 will not be visible either for the Cherenkov Telescope Array.

  17. Production of Ac-225 for cancer therapy by photon-induced transmutation of Ra-226.

    Science.gov (United States)

    Melville, G; Meriarty, H; Metcalfe, P; Knittel, T; Allen, B J

    2007-09-01

    The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. The production of Ac-225 has been achieved using bremsstrahlung photons from an 18 MV medical linear accelerator (linac) to bombard a Ra-226 target. A linac dose of 2800 Gy produced about 64 microCi of Ra-225, which decays to Ac-225. This result, while consistent with the theoretical calculations, is far too low to be of practical use. A more powerful linac is required that runs at a higher current, longer pulse length and higher frequency for practical production. This process could also lead to the reduction of the nuclear waste product Ra-226.

  18. Geant4 simulations of the lead fluoride calorimeter

    CERN Document Server

    Savchenko, A A; Dabagov, S B; Anastasi, A; Venanzoni, G; Strikhanov, M N

    2016-01-01

    In this paper we simulate the emission by charged particles in complex structures with help of Geant4. We take into account Cherenkov radiation, transition radiation, bremsstrahlung, pair production and other accompanying processes. As an application we investigate the full size electromagnetic calorimeter for the muon g-2 experiment at Fermilab. A calorimeter module (24 are expected in the experiment) consists of a Delrin front panel for installation of the laser calibration system, 54 PbF2 Cherenkov crystals wrapped by the black Millipore paper, and silicon photo-multiplier sensors. We report here on a simulation of radiation from positrons passing through the calorimeter system. We carry out the simulation using Geant4 toolkit, which provides a complete set of tools for all areas of detector simulation: geometry, tracking, detector response, run, event and track management, and visualization. We consider Cherenkov photons expansion when a positron moves down through the calorimeter at the arbitrary angle o...

  19. Behavior of a plasma in a high-density gas-embedded Z-pinch configuration

    Energy Technology Data Exchange (ETDEWEB)

    Shlachter, J.S.

    1982-05-01

    The theoretical analysis of a high density Z-pinch (HDZP) begins with an examination of the steady state energy balance between ohmic heating and bremsstrahlung radiation losses for a plasma column in pressure equilibrium. The model is then expanded to include the time-varying internal energy and results in a quasi-equilibrium prescription for the load current through a constant radius plasma channel. This set of current waveforms is useful in the design of experimental systems. The behavior of a plasma for physically realizable conditions is first examined by allowing adiabatic changes in the column radius. A more complete model is then developed by incorporating inertial effects into the momentum equation, and the resultant global MHD computational model is compared with more sophisticated, and costly, one- and two-dimensional computer simulations. These comparisons demonstrate the advantages of the global MHD description over previously developed zero-dimensional models.

  20. Terrestrial gamma-ray flash production by lightning

    Science.gov (United States)

    Carlson, Brant E.

    Terrestrial gamma-ray flashes (TGFs) are brief flashes of gamma-rays originating in the Earth's atmosphere and observed by satellites. First observed in 1994 by the Burst And Transient Source Experiment on board the Compton Gamma-Ray Observatory, TGFs consist of one or more ˜1 ms pulses of gamma-rays with a total fluence of ˜1/cm2, typically observed when the satellite is near active thunderstorms. TGFs have subsequently been observed by other satellites to have a very hard spectrum (harder than dN/d E ∝ 1/ E ) that extends from below 25 keV to above 20 MeV. When good lightning data exists, TGFs are closely associated with measurable lightning discharge. Such discharges are typically observed to occur within 300 km of the sub-satellite point and within several milliseconds of the TGF observation. The production of these intense energetic bursts of photons is the puzzle addressed herein. The presence of high-energy photons implies a source of bremsstrahlung, while bremsstrahlung implies a source of energetic electrons. As TGFs are associated with lightning, fields produced by lightning are naturally suggested to accelerate these electrons. Initial ideas about TGF production involved electric fields high above thunderstorms as suggested by upper atmospheric lightning research and the extreme energies required for lower-altitude sources. These fields, produced either quasi-statically by charges in the cloud and ionosphere or dynamically by radiation from lightning strokes, can indeed drive TGF production, but the requirements on the source lightning are too extreme and therefore not common enough to account for all existing observations. In this work, studies of satellite data, the physics of energetic electron and photon production, and consideration of lightning physics motivate a new mechanism for TGF production by lightning current pulses. This mechanism is then developed and used to make testable predictions. TGF data from satellite observations are compared

  1. X-ray observations of SN 1006 with INTEGRAL

    DEFF Research Database (Denmark)

    Kalemci, E.; Reynolds, S.P.; Boggs, S.E.

    2006-01-01

    The remnant of the supernova of 1006 AD, the remnant first showing evidence for the presence of X-ray synchrotron emission from shock-accelerated electrons, was observed for similar to 1000 ks with INTEGRAL in order to study electron acceleration to very high energies. The aim of the observation...... was to characterize the synchrotron emission and attempt to detect nonthermal bremsstrahlung using the combination of IBIS and JEM-X spatial and spectral coverage. The source was detected with JEM-X between the 2.4 and 8.4 keV bands and was not detected with either ISGRI or SPI above 20 keV. The ISGRI upper limit...

  2. Combined performance studies for electrons at the 2004 ATLAS combined test-beam

    Science.gov (United States)

    Abat, E.; Abdallah, J. M.; Addy, T. N.; Adragna, P.; Aharrouche, M.; Ahmad, A.; Akesson, T. P. A.; Aleksa, M.; Alexa, C.; Anderson, K.; Andreazza, A.; Anghinolfi, F.; Antonaki, A.; Arabidze, G.; Arik, E.; Atkinson, T.; Baines, J.; Baker, O. K.; Banfi, D.; Baron, S.; Barr, A. J.; Beccherle, R.; Beck, H. P.; Belhorma, B.; Bell, P. J.; Benchekroun, D.; Benjamin, D. P.; Benslama, K.; Bergeaas Kuutmann, E.; Bernabeu, J.; Bertelsen, H.; Binet, S.; Biscarat, C.; Boldea, V.; Bondarenko, V. G.; Boonekamp, M.; Bosman, M.; Bourdarios, C.; Broklova, Z.; Burckhart Chromek, D.; Bychkov, V.; Callahan, J.; Calvet, D.; Canneri, M.; Capeáns Garrido, M.; Caprini, M.; Cardiel Sas, L.; Carli, T.; Carminati, L.; Carvalho, J.; Cascella, M.; Castillo, M. V.; Catinaccio, A.; Cauz, D.; Cavalli, D.; Cavalli Sforza, M.; Cavasinni, V.; Cetin, S. A.; Chen, H.; Cherkaoui, R.; Chevalier, L.; Chevallier, F.; Chouridou, S.; Ciobotaru, M.; Citterio, M.; Clark, A.; Cleland, B.; Cobal, M.; Cogneras, E.; Conde Muino, P.; Consonni, M.; Constantinescu, S.; Cornelissen, T.; Correard, S.; Corso Radu, A.; Costa, G.; Costa, M. J.; Costanzo, D.; Cuneo, S.; Cwetanski, P.; Da Silva, D.; Dam, M.; Dameri, M.; Danielsson, H. O.; Dannheim, D.; Darbo, G.; Davidek, T.; De, K.; Defay, P. O.; Dekhissi, B.; Del Peso, J.; Del Prete, T.; Delmastro, M.; Derue, F.; Di Ciaccio, L.; Di Girolamo, B.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Dobos, D.; Dobson, M.; Dolgoshein, B. A.; Dotti, A.; Drake, G.; Drasal, Z.; Dressnandt, N.; Driouchi, C.; Drohan, J.; Ebenstein, W. L.; Eerola, P.; Efthymiopoulos, I.; Egorov, K.; Eifert, T. F.; Einsweiler, K.; El Kacimi, M.; Elsing, M.; Emelyanov, D.; Escobar, C.; Etienvre, A. I.; Fabich, A.; Facius, K.; Fakhr-Edine, A. I.; Fanti, M.; Farbin, A.; Farthouat, P.; Fassouliotis, D.; Fayard, L.; Febbraro, R.; Fedin, O. L.; Fenyuk, A.; Fergusson, D.; Ferrari, P.; Ferrari, R.; Ferreira, B. C.; Ferrer, A.; Ferrere, D.; Filippini, G.; Flick, T.; Fournier, D.; Francavilla, P.; Francis, D.; Froeschl, R.; Froidevaux, D.; Fullana, E.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Gallas, M.; Gallop, B. J.; Gameiro, S.; Gan, K. K.; Garcia, R.; Garcia, C.; Gavrilenko, I. L.; Gemme, C.; Gerlach, P.; Ghodbane, N.; Giakoumopoulou, V.; Giangiobbe, V.; Giokaris, N.; Glonti, G.; Goettfert, T.; Golling, T.; Gollub, N.; Gomes, A.; Gomez, M. D.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorfine, G.; Gorini, B.; Goujdami, D.; Grahn, K.-J.; Grenier, P.; Grigalashvili, N.; Grishkevich, Y.; Grosse-Knetter, J.; Gruwe, M.; Guicheney, C.; Gupta, A.; Haeberli, C.; Haertel, R.; Hajduk, Z.; Hakobyan, H.; Hance, M.; Hansen, J. D.; Hansen, P. H.; Hara, K.; Harvey, A., Jr.; Hawkings, R. J.; Heinemann, F. E. W.; Henriques Correia, A.; Henss, T.; Hervas, L.; Higon, E.; Hill, J. C.; Hoffman, J.; Hostachy, J. Y.; Hruska, I.; Hubaut, F.; Huegging, F.; Hulsbergen, W.; Hurwitz, M.; Iconomidou-Fayard, L.; Jansen, E.; Jen-La Plante, I.; Johansson, P. D. C.; Jon-And, K.; Joos, M.; Jorgensen, S.; Joseph, J.; Kaczmarska, A.; Kado, M.; Karyukhin, A.; Kataoka, M.; Kayumov, F.; Kazarov, A.; Keener, P. T.; Kekelidze, G. D.; Kerschen, N.; Kersten, S.; Khomich, A.; Khoriauli, G.; Khramov, E.; Khristachev, A.; Khubua, J.; Kittelmann, T. H.; Klingenberg, R.; Klinkby, E. B.; Kodys, P.; Koffas, T.; Kolos, S.; Konovalov, S. P.; Konstantinidis, N.; Kopikov, S.; Korolkov, I.; Kostyukhin, V.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; Kulchitsky, Y.; Lacasta, C.; Lafaye, R.; Laforge, B.; Lampl, W.; Lanni, F.; Laplace, S.; Lari, T.; Le Bihan, A.-C.; Lechowski, M.; Ledroit-Guillon, F.; Lehmann, G.; Leitner, R.; Lelas, D.; Lester, C. G.; Liang, Z.; Lichard, P.; Liebig, W.; Lipniacka, A.; Lokajicek, M.; Louchard, L.; Lourerio, K. F.; Lucotte, A.; Luehring, F.; Lund-Jensen, B.; Lundberg, B.; Ma, H.; Mackeprang, R.; Maio, A.; Maleev, V. P.; Malek, F.; Mandelli, L.; Maneira, J.; Mangin-Brinet, M.; Manousakis, A.; Mapelli, L.; Marques, C.; Garcia, S. Marti i.; Martin, F.; Mathes, M.; Mazzanti, M.; McFarlane, K. W.; McPherson, R.; Mchedlidze, G.; Mehlhase, S.; Meirosu, C.; Meng, Z.; Meroni, C.; Mialkovski, V.; Mikulec, B.; Milstead, D.; Minashvili, I.; Mindur, B.; Mitsou, V. A.; Moed, S.; Monnier, E.; Moorhead, G.; Morettini, P.; Morozov, S. V.; Mosidze, M.; Mouraviev, S. V.; Moyse, E. W. J.; Munar, A.; Myagkov, A.; Nadtochi, A. V.; Nakamura, K.; Nechaeva, P.; Negri, A.; Nemecek, S.; Nessi, M.; Nesterov, S. Y.; Newcomer, F. M.; Nikitine, I.; Nikolaev, K.; Nikolic-Audit, I.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olszowska, J.; Onofre, A.; Padilla Aranda, C.; Paganis, S.; Pallin, D.; Pantea, D.; Paolone, V.; Parodi, F.; Parsons, J.; Parzhitskiy, S.; Pasqualucci, E.; Passmored, S. M.; Pater, J.; Patrichev, S.; Peez, M.; Perez Reale, V.; Perini, L.; Peshekhonov, V. D.; Petersen, J.; Petersen, T. C.; Petti, R.; Phillips, P. W.; Pina, J.; Pinto, B.; Podlyski, F.; Poggioli, L.; Poppleton, A.; Poveda, J.; Pralavorio, P.; Pribyl, L.; Price, M. J.; Prieur, D.; Puigdengoles, C.; Puzo, P.; RØhne, O.; Ragusa, F.; Rajagopalan, S.; Reeves, K.; Reisinger, I.; Rembser, C.; Bruckman de Renstrom, P. A.; Reznicek, P.; Ridel, M.; Risso, P.; Riu, I.; Robinson, D.; Roda, C.; Roe, S.; Rohne, O.; Romaniouk, A.; Rousseau, D.; Rozanov, A.; Ruiz, A.; Rusakovich, N.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Salto, O.; Salvachua, B.; Salzburger, A.; Sandaker, H.; Santamarina Rios, C.; Santi, L.; Santoni, C.; Saraiva, J. G.; Sarri, F.; Sauvage, G.; Says, L. P.; Schaefer, M.; Schegelsky, V. A.; Schiavi, C.; Schieck, J.; Schlager, G.; Schlereth, J.; Schmitt, C.; Schultes, J.; Schwemling, P.; Schwindling, J.; Seixas, J. M.; Seliverstov, D. M.; Serin, L.; Sfyrla, A.; Shalanda, N.; Shaw, C.; Shin, T.; Shmeleva, A.; Silva, J.; Simion, S.; Simonyan, M.; Sloper, J. E.; Smirnov, S. Yu; Smirnova, L.; Solans, C.; Solodkov, A.; Solovianov, O.; Soloviev, I.; Sosnovtsev, V. V.; Spanò, F.; Speckmayer, P.; Stancu, S.; Stanek, R.; Starchenko, E.; Straessner, A.; Suchkov, S. I.; Suk, M.; Szczygiel, R.; Tarrade, F.; Tartarelli, F.; Tas, P.; Tayalati, Y.; Tegenfeldt, F.; Teuscher, R.; Thioye, M.; Tikhomirov, V. O.; Timmermans, C. J. W. P.; Tisserant, S.; Toczek, B.; Tremblet, L.; Troncon, C.; Tsiareshka, P.; Tyndel, M.; Karagoez Unel, M.; Unal, G.; Unel, G.; Usai, G.; Van Berg, R.; Valero, A.; Valkar, S.; Valls, J. A.; Vandelli, W.; Vannucci, F.; Vartapetian, A.; Vassilakopoulos, V. I.; Vasilyeva, L.; Vazeille, F.; Vernocchi, F.; Vetter-Cole, Y.; Vichou, I.; Vinogradov, V.; Virzi, J.; Vivarelli, I.; de Vivie, J. B.; Volpi, M.; Anh, T. Vu; Wang, C.; Warren, M.; Weber, J.; Weber, M.; Weidberg, A. R.; Weingarten, J.; Wells, P. S.; Werner, P.; Wheeler, S.; Wiessmann, M.; Wilkens, H.; Williams, H. H.; Wingerter-Seez, I.; Yasu, Y.; Zaitsev, A.; Zenin, A.; Zenis, T.; Zenonos, Z.; Zhang, H.; Zhelezko, A.; Zhou, N.

    2010-11-01

    In 2004 at the ATLAS (A Toroidal LHC ApparatuS) combined test beam, one slice of the ATLAS barrel detector (including an Inner Detector set-up and the Liquid Argon calorimeter) was exposed to particles from the H8 SPS beam line at CERN. It was the first occasion to test the combined electron performance of ATLAS. This paper presents results obtained for the momentum measurement p with the Inner Detector and for the performance of the electron measurement with the LAr calorimeter (energy E linearity and resolution) in the presence of a magnetic field in the Inner Detector for momenta ranging from 20 GeV/c to 100 GeV/c. Furthermore the particle identification capabilities of the Transition Radiation Tracker, Bremsstrahlungs-recovery algorithms relying on the LAr calorimeter and results obtained for the E/p ratio and a way how to extract scale parameters will be discussed.

  3. Effects of fluid viscosity on a moving sonoluminescing bubble.

    Science.gov (United States)

    Sadighi-Bonabi, Rasoul; Mirheydari, Mona; Rezaee, Nastaran; Ebrahimi, Homa

    2011-08-01

    Based on the quasi-adiabatic model, the parameters of the bubble interior for a moving single bubble sonoluminescence in water, adiponitrile, and N-methylformamide are calculated for various fluid viscosities. By using a complete form of the hydrodynamic force, the bubble trajectory is calculated for a moving single bubble sonoluminescence (m-SBSL). It is found that as the fluid viscosity increases, the unique circular path changes to an ellipsoidal and then linear form and along this incrementally increase of viscosity the light intensity increases. By using the Bremsstrahlung model to describe the bubble radiation, gradual increase of the viscosity results in brighter emissions. It is found that in fluids with higher viscosity the light intensity decreases as time passes.

  4. A bright point source of ultrashort hard x-rays from laser bioplasmas

    CERN Document Server

    Krishnamurthy, M; Lad, Amit D; Ahmad, Saima; Narayanan, V; Rajeev, R; Kundu, M; Kumar, G Ravindra; Ray, Krishanu

    2010-01-01

    Micro and nano structures scatter light and amplify local electric fields very effectively. Energy incident as intense ultrashort laser pulses can be converted to x-rays and hot electrons more efficiently with a substrate that suitably modifies the local fields. Here we demonstrate that coating a plain glass surface with a few micron thick layer of an ubiquitous microbe, {\\it Escherichia coli}, catapults the brightness of hard x-ray bremsstrahlung emission (up to 300 keV) by more than two orders of magnitude at an incident laser intensity of 10$^{16}$ W cm$^{-2}$. This increased yield is attributed to the local enhancement of electric fields around individual {\\it E. coli} cells and is reproduced by detailed particle-in-cell (PIC) simulations. This combination of laser plasmas and biological targets can lead to turnkey, multi-kilohertz and environmentally safe sources of hard x-rays.

  5. Vavilov-Cherenkov and Synchrotron Radiation Foundations and Applications

    CERN Document Server

    Afanasiev, G. N

    2005-01-01

    The theory of the Vavilov-Cherenkov radiation observed by Cherenkov in 1934 was created by Tamm, Frank and Ginsburg who associated the observed blue light with the uniform charge motion of a charge at a velocity greater than the velocity of light in the medium. On the other hand, Vavilov, Cherenkov's teacher, attributed the observed blue light to the deceleration of electrons. This has given rise to the appearance of papers in which the radiation of a charge uniformly moving in a finite space interval was related to the Bremsstrahlung arising at the end points of the motion interval. This monograph is intended for students of the third year and higher, for postgraduates, for professional scientists (both experimentalists and theoreticians) dealing with Vavilov-Cherenkov and synchrotron radiation. An acquaintance with the three volumes of the Landau and Lifshitz course (Quantum Mechanics, Classical Field Theory and Macroscopic Electrodynamics) is sufficient for understanding the text.

  6. Clinical feasibility of {sup 90}Y digital PET/CT for imaging microsphere biodistribution following radioembolization

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Chadwick L.; Binzel, Katherine; Zhang, Jun; Knopp, Michael V. [The Ohio State University Wexner Medical Center, Wright Center of Innovation in Biomedical Imaging, Department of Radiology, Columbus, OH (United States); Wuthrick, Evan J. [The Ohio State University Wexner Medical Center, Department of Radiation Oncology, Columbus, OH (United States)

    2017-07-15

    The purpose of this study was to evaluate the clinical feasibility of next generation solid-state digital photon counting PET/CT (dPET/CT) technology and imaging findings in patients following {sup 90}Y microsphere radioembolization in comparison with standard of care (SOC) bremsstrahlung SPECT/CT (bSPECT/CT). Five patients underwent SOC {sup 90}Y bremsstrahlung imaging immediately following routine radioembolization with 3.5 ± 1.7 GBq of {sup 90}Y-labeled glass microspheres. All patients also underwent dPET/CT imaging at 29 ± 11 h following radioembolization. Matched pairs comparison was used to compare image quality, image contrast and {sup 90}Y biodistribution between dPET/CT and bSPECT/CT images. Volumetric assessments of {sup 90}Y activity using different isocontour thresholds on dPET/CT and bSPECT/CT images were also compared. Digital PET/CT consistently provided better visual image quality and {sup 90}Y-to-background image contrast while depicting {sup 90}Y biodistribution than bSPECT/CT. Isocontour volumetric assessment using a 1% threshold precisely outlined {sup 90}Y activity and the treatment volume on dPET/CT images, whereas a more restrictive 20% threshold on bSPECT/CT images was needed to obtain comparable treatment volumes. The use of a less restrictive 10% threshold isocontour on bSPECT/CT images grossly overestimated the treatment volume when compared with the 1% threshold on dPET/CT images. Digital PET/CT is clinically feasible for the assessment of {sup 90}Y microsphere biodistribution following radioembolization, and provides better visual image quality and image contrast than routine bSPECT/CT with comparable acquisition times. With further optimization and clinical validation, dPET technology may allow faster and more accurate imaging-based assessment of {sup 90}Y microsphere biodistribution. (orig.)

  7. Dosimetry of rotational partial-skin electron irradiation.

    Science.gov (United States)

    Müller-Sievers, K; Ertan, E; Kober, B

    2001-02-01

    Often, the most appropriate treatment for superficially and extensively spreading tumors of the skin is to use electron irradiation at enlarged distances. Rotational skin electron irradiation is a proven method for the treatment of the entire skin surface. We here report modifications of this technique in the set-up of partial-skin electron irradiation and the results of dosimetric examinations with regard to optimal shielding, dose profiles and depth dose curves under various irradiation conditions. Irradiation was performed using electron beams with nominal energies of 6 MeV from a linear accelerator. The phantom was located on a rotating platform at a source-surface distance SSD=300 cm. A horizontal slit aperture (height: 32 cm) within a 2 cm thick polymethylmethacrylate (PMMA) shielding plate near the phantom was used to define the size of the irradiated region. Influences on dose distributions due to scattering processes on the PMMA edges were investigated using a flat ionization chamber and films. Absolute dose measurements and film calibration were made with the flat chamber. The quality of bremsstrahlung radiation behind the shielding was determined with a thimble ionization chamber in the phantom. The results of rotational partial-skin electron irradiation reveal some of the investigated shielding geometries to be optimal. Depth dose distributions and dose rates correspond to the results obtained in total skin electron rotational irradiation. It is possible to apply the dose superficially in the first millimeters of the skin; the dose maximum is located at a depth of 0-2 mm, the 80% isodose at 9 mm. The amount of bremsstrahlung contamination is 2.5%. The local amount of absorbed dose per monitor unit depends strongly on patient/phantom cross-section geometry. At our institute, rotational partial-skin electron irradiation was implemented into clinical routine in 1997.

  8. A high-resolution time-of-flight spectrometer for fission fragments and ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosev, Krasimir Milchev

    2007-07-01

    For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ({sup 226}Ra,{sup 222}Rn,{sup 210}Po,{sup 218}Po,{sup 214}Po) {alpha}-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a {sup 238}U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

  9. Development of the Tagger Microscope & Analysis of Spin Density Matrix Elements in gamma-p -> phi-p for the GlueX Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Alexander E. [Carnegie Mellon Univ., Pittsburgh, PA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2017-05-31

    The quark model has been successful in classifying the spectrum of mesons observed since the 1960s, however, it fails to explain some of the measured bound states. Lattice QCD predictions have shown that an excited gluonic field may contribute to the quantum numbers of the bound state and form hybrid mesons, qq-bar-g, where g is a constituent gluon. It is possible for some hybrids to possess quantum numbers forbidden by the quark model and are known as \\smoking gun" hybrids due to their lack of mixing with conventional qq-bar states. The GlueX photoproduction experiment at Jefferson Lab in Newport News, VA is designed to study hybrid mesons and to map their spectrum. A 12 GeV electron beam produces 9 GeV linearly polarized photons via coherent bremsstrahlung in a diamond radiator which are incident on a liquid H2 target. In order to determine the photon energy, the use of a tagging spectrometer which measures the energy of the post-bremsstrahlung electron is required. The tagger microscope is a scintillating fiber detector designed to measure the energy of electrons corresponding to the polarized photons. The main focus of this work is the design and construction of the tagger microscope electronics as well as the calibration of the microscope within the experiment. Additionally, the analysis of the reaction gamma-p -> phi-p, where phi (1020) -> K+K-, is discussed. This analysis provides a high-level calibration for GlueX in regards to understanding the acceptance and sensitivity of the detectors to mesons with strange quark content. By studying the phi with linearly polarized photons, information on the production mechanism can be extracted. The measurement of the phi spin-density matrix elements are shown and compared with past data which are found to be in agreement.

  10. Giant dipole resonance in very hot nuclei of mass A~=115

    Science.gov (United States)

    Suomijärvi, T.; Blumenfeld, Y.; Piattelli, P.; Le Faou, J. H.; Agodi, C.; Alamanos, N.; Alba, R.; Auger, F.; Bellia, G.; Chomaz, Ph.; Coniglione, R.; del Zoppo, A.; Finocchiaro, P.; Frascaria, N.; Gaardhøje, J. J.; Garron, J. P.; Gillibert, A.; Lamehi-Rachti, M.; Liguori-Neto, R.; Maiolino, C.; Migneco, E.; Russo, G.; Roynette, J. C.; Santonocito, D.; Sapienza, P.; Scarpaci, J. A.; Smerzi, A.

    1996-05-01

    Gamma rays, light charged particles, and evaporation residues emitted from hot nuclei formed in the 36Ar+90Zr reaction at 27 MeV/nucleon have been measured at the GANIL facility with the 4π barium fluoride multidetector MEDEA. The combination of the residue and particle measurements shows that nuclei with masses around 115 and excitation energies between 350 and 550 MeV are produced. The γ spectra measured in coincidence with the evaporation residues exhibit three components: a low-energy statistical component, a high-energy contribution due to nucleon-nucleon bremsstrahlung during the initial stages of the collision, and a contribution from the decay of the giant dipole resonance built on highly excited states. The characteristics of the bremsstrahlung component are in agreement with previously published systematics. The γ yield from the decay of the giant dipole resonance remains constant over the excitation energy range studied. A comparison with other experiments shows that the N/Z asymmetry in the entrance channel does not affect the γ yield. Statistical calculations performed using the code CASCADE and supposing a fixed width and full sum rule strength for the dipole resonance strongly overpredict the data. The hypothesis of a continuously increasing width of the resonance with temperature gives a better agreement with experiment near the centroid of the resonance but overpredicts the γ spectra at higher energies. The best account of the data is given by assuming a cutoff of γ emission from the resonance above an excitation energy of approximately 250 MeV. This cutoff is discussed in terms of the time necessary to equilibrate the dipole oscillations with the hot compound nucleus. Finally, some evidence is given for a possible new low-energy component of the dipole strength at very high temperatures.

  11. Giant dipole resonance in very hot nuclei of mass {ital A}{approx_equal}115

    Energy Technology Data Exchange (ETDEWEB)

    Suomijaervi, T.; Blumenfeld, Y.; Piattelli, P.; Le Faou, J.H.; Agodi, C.; Alamanos, N.; Alba, R.; Auger, F.; Bellia, G.; Chomaz, P.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Frascaria, N.; Gaardho/je, J.J.; Garron, J.P.; Gillibert, A.; Lamehi-Rachti, M.; Liguori-Neto, R.; Maiolino, C.; Migneco, E.; Russo, G.; Roynette, J.C.; Santonocito, D.; Sapienza, P.; Scarpaci, J.A.; Smerzi, A. [Institut de Physique Nucleaire, IN2P3-CNRS, 91406 Orsay, France INFN-Laboratorio Nazionale del Sud, Via S. Sofia 44, 95123, Catania, Italy SPhN, DAPNIA, CEN Saclay, 91191 Gif sur Yvette, France GANIL, BP 5027, 14021 Caen, France The Niels Bohr Institute, University of Copenhagen, DK-2100 O/ (Denmark)

    1996-05-01

    Gamma rays, light charged particles, and evaporation residues emitted from hot nuclei formed in the {sup 36}Ar+{sup 90}Zr reaction at 27 MeV/nucleon have been measured at the GANIL facility with the 4{pi} barium fluoride multidetector MEDEA. The combination of the residue and particle measurements shows that nuclei with masses around 115 and excitation energies between 350 and 550 MeV are produced. The {gamma} spectra measured in coincidence with the evaporation residues exhibit three components: a low-energy statistical component, a high-energy contribution due to nucleon-nucleon bremsstrahlung during the initial stages of the collision, and a contribution from the decay of the giant dipole resonance built on highly excited states. The characteristics of the bremsstrahlung component are in agreement with previously published systematics. The {gamma} yield from the decay of the giant dipole resonance remains constant over the excitation energy range studied. A comparison with other experiments shows that the {ital N}/{ital Z} asymmetry in the entrance channel does not affect the {gamma} yield. Statistical calculations performed using the code CASCADE and supposing a fixed width and full sum rule strength for the dipole resonance strongly overpredict the data. The hypothesis of a continuously increasing width of the resonance with temperature gives a better agreement with experiment near the centroid of the resonance but overpredicts the {gamma} spectra at higher energies. The best account of the data is given by assuming a cutoff of {gamma} emission from the resonance above an excitation energy of approximately 250 MeV. This cutoff is discussed in terms of the time necessary to equilibrate the dipole oscillations with the hot compound nucleus. Finally, some evidence is given for a possible new low-energy component of the dipole strength at very high temperatures. {copyright} {ital 1996 The American Physical Society.}

  12. Accretion and gas flows near Sagittarius A*: Toward an understanding of the central parsec of the Milky Way

    Science.gov (United States)

    Coker, Robert Francis

    1999-12-01

    The strong radio emission from Sgr A*, an object located at the dynamical center of the Milky Way, has been attributed to accretion of interstellar gas by a supermassive compact object or dense cluster of objects. We show that any dynamically stable cluster of objects cannot compress the ambient magnetic field or heat the accreting gas sufficiently to reproduce the spectrum of Sgr A*, reaffirming the paradigm that Sgr A* is a single supermassive black hole. We investigate how such a black hole would interact with its surroundings and attempt to determine observational consequences of this interaction. The complexity of the gas, dust, and stellar dynamics of the central parsec of the Galaxy complicates this problem, however. Focusing our attention on the black hole itself but being constrained by observations of the surrounding gas and stars, we have constructed models of the accretion process. We examine two types of accretion models. The first, involving a cold, massive, fossilized accretion disk, is found to generate too much infrared radiation as infalling gas impacts the disk. The second model is spherical accretion, in which the radio emission from Sgr A* is dominated by magnetic bremsstrahlung. Such a model requires accurate emissivities for a wide range of temperatures and field strengths. In this work, we derive the magnetic bremsstrahlung emissivities and apply them to the spherical accretion model, yielding a spectrum that is fully consistent with the radio emission from Sgr A*. We empirically determine a magnetic field profile that suggests the presence of other phenomena, such as a central magnetic dynamo. In addition, the model predicts that the observed high energy emission from the Galactic Center region is not dominated by emission from the central black hole and its environs.

  13. Beam Spin Asymmetry Measurements for Two Pion Photoproduction at CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark D. [Univ. of Glasgow, Scotland (United Kingdom)

    2015-09-01

    The overarching goal of this analysis, and many like it, is to develop our understanding of the strong force interactions within the nucleon by examining the nature of their excitation spectra. As the resonances of these spectra have very short lifetimes (tau = 1x10-23 s) and often have very similar masses, it is often impossible to directly observe resonances in the excitation spectra of nucleons. Polarization observables allow us to study the resonances by looking at how they affect the spin state of final state particles. The beam asymmetry is a polarization observable that allows us to detect the sensitivity of these resonances, and other transition mechanisms, to the electric vector orientation of incident photons. Presented in this thesis are first measurements of the beam asymmetries in the resonant region for the reaction channel pgamma p --> p π+ π-focusing on the intermediate mesonic states rho^0 and f^0, and the final state pions. The analysis used data from the g8b experiment undertaken at the Thomas Jefferson National Accelerator Facility (JLab), the first experiment at JLab to use a linearly polarized photon beam. Using the coherent Bremsstrahlung facility and the CLAS detector of Hall B at JLab allowed for many multi-channel reactions to be detected and the first measurements of many polarization observables including those presented here. A brief overview of the theoretical framework used to undertake this analysis is given, followed by a description of the experimental details of the facilities used, then a description of the calibration of the Bremsstrahlung tagging facility which the author undertook, and finally the analysis is presented and the resulting measurements.

  14. Comparison of quantitative Y-90 SPECT and non-time-of-flight PET imaging in post-therapy radioembolization of liver cancer.

    Science.gov (United States)

    Yue, Jianting; Mauxion, Thibault; Reyes, Diane K; Lodge, Martin A; Hobbs, Robert F; Rong, Xing; Dong, Yinfeng; Herman, Joseph M; Wahl, Richard L; Geschwind, Jean-François H; Frey, Eric C

    2016-10-01

    Radioembolization with yttrium-90 microspheres may be optimized with patient-specific pretherapy treatment planning. Dose verification and validation of treatment planning methods require quantitative imaging of the post-therapy distribution of yttrium-90 (Y-90). Methods for quantitative imaging of Y-90 using both bremsstrahlung SPECT and PET have previously been described. The purpose of this study was to compare the two modalities quantitatively in humans. Calibration correction factors for both quantitative Y-90 bremsstrahlung SPECT and a non-time-of-flight PET system without compensation for prompt coincidences were developed by imaging three phantoms. The consistency of these calibration correction factors for the different phantoms was evaluated. Post-therapy images from both modalities were obtained from 15 patients with hepatocellular carcinoma who underwent hepatic radioembolization using Y-90 glass microspheres. Quantitative SPECT and PET images were rigidly registered and the total liver activities and activity distributions estimated for each modality were compared. The activity distributions were compared using profiles, voxel-by-voxel correlation and Bland-Altman analyses, and activity-volume histograms. The mean ± standard deviation of difference in the total activity in the liver between the two modalities was 0% ± 9% (range -21%-18%). Voxel-by-voxel comparisons showed a good agreement in regions corresponding roughly to treated tumor and treated normal liver; the agreement was poorer in regions with low or no expected activity, where PET appeared to overestimate the activity. The correlation coefficients between intrahepatic voxel pairs for the two modalities ranged from 0.86 to 0.94. Cumulative activity volume histograms were in good agreement. These data indicate that, with appropriate reconstruction methods and measured calibration correction factors, either Y-90 SPECT/CT or Y-90 PET/CT can be used for quantitative post-therapy monitoring of Y

  15. A practical method to generate brilliant hard x-rays with a tabletop electron storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, H. [Ritsumeikan Univ., Shiga (Japan); Amano, D.; Miyade, H. [Sumitomo Heavy Industries, Ltd., Tanashi-City (Japan)

    1995-12-31

    With electron storage rings not only synchrotron radiation(SR) but also bremsstrahlung(BS) from a thin target placed in the electron orbit are mechanisms to generate brilliant x-ray beams. The calculated brilliance of BS with a 50 MeV storage ring, which is nearly 10{sup 13} photons/s, mrad{sup 2}, mm{sup 2}, 0.1% band width for 100 keV x-rays, exceeds that of SR from a 1 GeV storage ring. This photon energy spectrum is almost constant and extend up to the electron energy. The reasons for this high brilliance with this new radiation scheme is that the electron beams penetrating the thin target are utilized repeatedly, the narrow angular divergence of BS is determined by the kinematics of relativistic electron as same as SR, and the x-ray source size of the order of 1 {mu}m is determined by the size of thin target instead of electron beam sizes. Continuous injection of electron beam to the storage ring at full energy is the way to keep high and constant beam current. Peak current and repetition rate determine x-ray out put power. Note that the power of x-ray beam is also provided from a RF cavity of the storage ring. In this paper we will report some experimental results and discuss further application on a coherent bremsstrahlung generated from a set of stacked foils placed in the electron orbit of the ring. Resulting from these investigations the photon storage ring which is based on a 50 MeV exact circular electron storage ring could provide wide range of coherent and incoherent radiations from far infrared to hard x-ray in a practical amount of radiation power.

  16. A LabVIEW-based data acquisition system for the UTEP/Orsay Instrumented Collimator

    Energy Technology Data Exchange (ETDEWEB)

    Puga, A.; Cole, P.L. [UTEP, El Paso TX (United States)

    2001-09-01

    Full text: We have successfully employed an instrumented collimator of aperture 2 mm for the g8a run (summer, 2001) in Hall B of Jefferson Lab, which was designed and tested by UTEP and engineered and built by the Institut de Physique Nucl ire in Orsay, France. The instrumentation of the collimator consists of four radially mounted scintillator + light guide + PMT elements possessing a left-right, up-down symmetry, which afforded the beam of photons to be precisely aligned to the central axis of the collimator. The collimator was sensitive to rather modest beam motion of the order of a few tens of microns. We made use of the physical fact that the emission angle of the coherent Bremsstrahlung photon component is correlated with its energy for enhancing the degree of polarization of the photon beam. We can extract the spectral peak by tightly collimating the beam and thereby reduce the incoherent background, which further serves to increase the degree of polarization. The maximum polar angle is limited by the opening angle of the collimator, which gives the lower limit for the coherent Bremsstrahlung photon energy. To achieve polarizations exceeding 75%, we must collimate the beam to better than one half of a characteristic angle. This means for a collimator-goniometer distance of 22 m, the aperture of the collimator should be {approx} 2 mm for an incident electron energy of E{sub o} 5.7 GeV. We will report primarily on the bench top data acquisition system (DAQ), which interfaced LabVIEW through a SCSI connection to the VME back plane to readout CAEN QDC{sub s}. We employed this DAQ to test and calibrate the instrumented collimator. Our efforts were quite successful in that the device functioned beyond design specifications within one hour after the photon beam was directed onto the bore hole of the collimator. (Author)

  17. A HARD X-RAY POWER-LAW SPECTRAL CUTOFF IN CENTAURUS X-4

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, Deepto; Nowak, Michael A. [MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Tomsick, John A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Grefenstette, Brian W.; Fürst, Felix; Harrison, Fiona A.; Rana, Vikram [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Psaltis, Dimitrios [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States); Bachetti, Matteo; Barret, Didier [Observatoire Midi-Pyrénées, Université de Toulouse III - Paul Sabatier, F-31400 Toulouse (France); Christensen, Finn E. [Division of Astrophysics, National Space Institute, Technical University of Denmark, DK-2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Kaspi, Victoria M. [Department of Physics, McGill University, Montreal, PQ H3A 2T8 (Canada); Miller, Jon M. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Wik, Daniel R.; Zhang, William W. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wilms, Jörn, E-mail: deepto@mit.edu [Dr. Karl-Remeis-Sternwarte and Erlangen Centre for Astroparticle Physics, Universität Erlangen-Nürnberg, D-96049 Bamberg (Germany)

    2014-12-20

    The low-mass X-ray binary (LMXB) Cen X-4 is the brightest and closest (<1.2 kpc) quiescent neutron star transient. Previous 0.5-10 keV X-ray observations of Cen X-4 in quiescence identified two spectral components: soft thermal emission from the neutron star atmosphere and a hard power-law tail of unknown origin. We report here on a simultaneous observation of Cen X-4 with NuSTAR (3-79 keV) and XMM-Newton (0.3-10 keV) in 2013 January, providing the first sensitive hard X-ray spectrum of a quiescent neutron star transient. The 0.3-79 keV luminosity was 1.1×10{sup 33} D{sub kpc}{sup 2} erg s{sup –1}, with ≅60% in the thermal component. We clearly detect a cutoff of the hard spectral tail above 10 keV, the first time such a feature has been detected in this source class. We show that thermal Comptonization and synchrotron shock origins for the hard X-ray emission are ruled out on physical grounds. However, the hard X-ray spectrum is well fit by a thermal bremsstrahlung model with kT{sub e} = 18 keV, which can be understood as arising either in a hot layer above the neutron star atmosphere or in a radiatively inefficient accretion flow. The power-law cutoff energy may be set by the degree of Compton cooling of the bremsstrahlung electrons by thermal seed photons from the neutron star surface. Lower thermal luminosities should lead to higher (possibly undetectable) cutoff energies. We compare Cen X-4's behavior with PSR J1023+0038, IGR J18245–2452, and XSS J12270–4859, which have shown transitions between LMXB and radio pulsar modes at a similar X-ray luminosity.

  18. Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE-RBS

    Science.gov (United States)

    Zhou, Z.; Zhang, K.; Xia, C. D.; Liu, M. T.; Zhu, J. J.; An, Z.; Bai, B.

    2015-03-01

    A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271-1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB6 crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907-960 A.D.) had been propagated to the Waguantan kiln site of Guizhou Province in the Yuan Dynasty.

  19. Quantitative Comparison of Y-90 and Ge-68 PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Sangkeun; Kwak, Shin Hye; Lee, Jeong A; Song, Han Kyeol; Kang, Joo Hyun; Lim, Sang Moo; KIm, Kyeong Min [Korea Institute of Raiological and Medical Sciences, Seoul (Korea, Republic of); Jeong, Su Young [Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)

    2014-05-15

    The purpose of this study was to assess statistical characteristics and to improve count rate of image for enhancing Y-90 image quality by using non-parametric bootstrap method. The results showed that Y-90 PET image can be improved using non-parametric bootstrap method. PET data was able to be improved using non-parametric bootstrap method and it was verified with showing improved prompts rate. Y-90 PET image quality was improved and bias indicated that the bootstrapped image was more similar to the gold standard than other images. The non-parametric bootstrap method will be useful tool for enhancing Y-90 PET image and it will be expected to reduce time for acquisition and to elevate performance for diagnosis and treatment. Yttrium-90 (Y-90) radioembolization is one of the treatment methods unrespectable stage of hepatocellular carcinoma (HCC) and metastatic colon cancer to the liver. However, Y-90 radioembolization is a catheter-based therapy that delivers internal radiation to tumors, it results in greater radiation exposure to the tumors than using external radiation. Also, unlike other current therapies for the treatment of unresectable liver tumors, Y-90 radioembolization is much less often associated with toxicities such as abdominal pain, fever, nausea, and vomiting. Therefore Y-90 has been received much interest and studied by many researchers. Imaging of Y-90 has been conducted using most commonly gamma camera but quantitative PET imaging is required due to low sensitivity and resolution. Y-90 imaging is generally performed with SPECT by Bremsstrahlung photons. Unfortunately, the low image quality due to the nature of the Bremsstrahlung photon limits the quantitative accuracy of Y-90 SPECT. To overcome this limitation in SPECT imaging, Y-90 PET has been suggested as an alternative.

  20. Fermi LAT and WMAP observations of the supernova remnant HB 21

    Energy Technology Data Exchange (ETDEWEB)

    Pivato, G. [Dipartimento di Fisica e Astronomia " G. Galilei," Università di Padova, I-35131 Padova (Italy); Hewitt, J. W. [CRESST, University of Maryland, Baltimore County, Baltimore, MD 21250 (United States); Tibaldo, L. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Acero, F.; Brandt, T. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d' Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); De Palma, F.; Giordano, F. [Dipartimento di Fisica " M. Merlin" dell' Università e del Politecnico di Bari, I-70126 Bari (Italy); Janssen, G. H. [University of Manchester, Manchester, M13 9PL (United Kingdom); Jóhannesson, G. [Science Institute, University of Iceland, IS-107 Reykjavik (Iceland); Smith, D. A., E-mail: giovanna.pivato@pd.infn.it, E-mail: john.w.hewitt@nasa.gov, E-mail: ltibaldo@slac.stanford.edu [Centre d' Études Nucléaires de Bordeaux Gradignan, IN2P3/CNRS, Université Bordeaux 1, BP120, F-33175 Gradignan Cedex (France)

    2013-12-20

    We present the analysis of Fermi Large Area Telescope γ-ray observations of HB 21 (G89.0+4.7). We detect significant γ-ray emission associated with the remnant: the flux >100 MeV is 9.4 ± 0.8 (stat) ± 1.6 (syst) × 10{sup –11} erg cm{sup –2} s{sup –1}. HB 21 is well modeled by a uniform disk centered at l = 88.°75 ± 0.°04, b = +4.°65 ± 0.°06 with a radius of 1.°19 ± 0.°06. The γ-ray spectrum shows clear evidence of curvature, suggesting a cutoff or break in the underlying particle population at an energy of a few GeV. We complement γ-ray observations with the analysis of the WMAP 7 yr data from 23 to 93 GHz, achieving the first detection of HB 21 at these frequencies. In combination with archival radio data, the radio spectrum shows a spectral break, which helps to constrain the relativistic electron spectrum, and, in turn, parameters of simple non-thermal radiation models. In one-zone models multiwavelength data favor the origin of γ rays from nucleon-nucleon collisions. A single population of electrons cannot produce both γ rays through bremsstrahlung and radio emission through synchrotron radiation. A predominantly inverse-Compton origin of the γ-ray emission is disfavored because it requires lower interstellar densities than are inferred for HB 21. In the hadronic-dominated scenarios, accelerated nuclei contribute a total energy of ∼3 × 10{sup 49} erg, while, in a two-zone bremsstrahlung-dominated scenario, the total energy in accelerated particles is ∼1 × 10{sup 49} erg.