WorldWideScience

Sample records for 60-130 mev photons

  1. PHOTONS IN THE PROTON-INDUCED REACTION WITH IN AT E(P)=50-MEV

    BALANDA, A; BACELAR, JCS; BETAK, E; BORDEWIJK, JA; KRASZNAHORKA, A; VANDERPLOEG, H; SIEMSSEN, RH; WILSCHUT, HW; VANDERWOUDE, A

    1994-01-01

    Photon emission in proton-induced reactions at 50 MeV with In-115 was studied. Analyses of the measured photon spectrum show that the GDR couples to the compound states as well as to pre-equilibrium states. The centroid and width of the GDR strength function were determined as E(GDR) = 15.4 +/- 0.7

  2. Measurements of photon mass attenuation coefficients for Ge and BGO crystals at 10 MeV

    The photon mass attenuation coefficients of the important materials for γ-ray detection, Ge and BGO (Bi4Ge3O12) crystals, have been measured for 10.0 MeV γ-rays. The measurement system using the laser-Compton backscattering γ-rays and the high-resolution high-energy photon spectrometer has been developed and utilized. The effectiveness of the system achieving the total systematic uncertainties of 0.5% for the measurements of the photon mass attenuation coefficients was demonstrated. It was shown that the measured photon mass attenuation coefficients, 318.1±1.7 [cm2/g] for the Ge crystal and 425.2±2.4 [cm2/g] for the BGO crystal, agree within the achieved experimental uncertainties with the evaluated values including atomic and nuclear processes at 10.0 MeV. (author)

  3. Nuclear multifragmentation by 700–1500 MeV photons: New data of GRAAL experiment

    Nedorezov, V. G., E-mail: vladimir@cpc.inr.ac.ru; Lapik, A. M. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Collaboration: GRAAL Collaboration

    2015-12-15

    The cross sections of carbon nucleus photodisintegration into protons and neutrons with high multiplicity for photon energies from 700 to 1500 MeV were measured. The experiment was performed at the tagged photon beam of the GRAAL setup using the wide-aperture detector LAGRANγE. It was shown that multifragmentation up to complete disintegration into separate nucleons is initiated by elementary reactions of meson photoproduction with a subsequent intranuclear cascade.

  4. Thermoluminescence response of Ge-, Al- and Nd- doped optical fibers by 6 MeV - electron and 6 MeV - photon irradiations

    In this paper, we report the prediction of thermoluminescence responses of Neodymium-doped SiO2 optical fibre with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MeV - electron irradiations without requirement for experimental measurements. A technique has been developed to calculate prediction of 6 MeV - electron response of Neodymium-doped SiO2 optical fibre by observing the measured TL response of 6 MV - photon and the ratio of known measured photon/electron yield ratio distribution for Ge-doped, Al-doped optical fibre and standard TLD 100 dosimeter. The samples were kept in gelatin capsule an irradiated with 6 MV - photon at the dose range from 0.5 Gy to 4.0 Gy. Siemens model Primus 3368 linear accelerator located at Hospital Sultan Ismail, Johor Bahru has been used to deliver the photon beam to the samples. We found the average response ratio of 6 MV - photon and 6 MeV - electron in Ge-doped, Al-doped optical fibre and standard TLD-100 dosimeter are 0.83(3). Observing the measured value of 6 MV - photon irradiation this average ratio is useful to find the prediction of thermoluminescence responses by 6 MeV - electron irradiation of Neodymium-doped SiO2 optical fibre by the requirement for experimental measurements with various dose ranges from 0.5 Gy to 4.0 Gy by 6 MV - photon irradiations.

  5. Demonstration of multilayer reflective optics at photon energies above 0.6 MeV

    Brejnholt, Nicolai F.; Soufli, Regina; Descalle, Marie-Anne; Fernandez-Perea, Monica; Christensen, Finn Erland; Jakobsen, Anders Clemen; Honkimaeki, Veijo; Pivovaroff, Michael J.

    2014-01-01

    Focusing optics operating in the soft gamma-ray photon energy range can advance a range of scientific and technological applications that benefit from the large improvements in sensitivity and resolution that true imaging provides. An enabling technology to this end is multilayer coatings. We show that very short period multilayer coatings deposited on super-polished substrates operate efficiently above 0.6 MeV. These experiments demonstrate that Bragg scattering theory established for multil...

  6. Demonstration of multilayer reflective optics at photon energies above 0.6 MeV

    Brejnholt, Nicolai F.; Soufli, Regina; Descalle, Marie-Anne;

    2014-01-01

    Focusing optics operating in the soft gamma-ray photon energy range can advance a range of scientific and technological applications that benefit from the large improvements in sensitivity and resolution that true imaging provides. An enabling technology to this end is multilayer coatings. We show...... that very short period multilayer coatings deposited on super-polished substrates operate efficiently above 0.6 MeV. These experiments demonstrate that Bragg scattering theory established for multilayer applications as low as 1 eV continues to work well into the gamma-ray band. (C) 2014 Optical Society...

  7. Compton scattering from 12C using tagged photons in the energy range 65 - 115 MeV

    Myers, L S; Preston, M F; Anderson, M D; Annand, J R M; Boselli, M; Briscoe, W J; Brudvik, J; Capone, J I; Feldman, G; Fissum, K G; Hansen, K; Henshaw, S S; Isaksson, L; Jebali, R; Kovash, M A; Lewis, K; Lundin, M; MacGregor, I J D; Middleton, D G; Mittelberger, D E; Murray, M; Nathan, A M; Nutbeam, S; O'Rielly, G V; Schröder, B; Seitz, B; Stave, S C; Weller, H R

    2014-01-01

    Elastic scattering of photons from 12C has been investigated using quasi-monoenergetic tagged photons with energies in the range 65 - 115 MeV at laboratory angles of 60 deg, 120 deg, and 150 deg at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. A phenomenological model was employed to provide an estimate of the sensitivity of the 12C(g,g)12C cross section to the bound-nucleon polarizabilities.

  8. Methods for the measurement of the refractive index of MeV photons using total internal and external reflection

    Recently it has been theoretically and experimentally shown that for 1-10 MeV and 1-2 MeV photons, respectively, the refractive index of Si is greater than 1. Taking into account the difficulties of the carried out experiment it is proposed to measure directly the refractive index of Si and other materials detecting the total internal and external reflections.

  9. Measurements of 12C(→γ,pp) photon asymmetries for Eγ= 200–450 MeV

    Robinson, J; MacGregor, I.J.D.; Annand, J. R. M.; Aguar-Bartolomé, P.; Akasoy, L. K.; Arends, H.J.(Institut für Kernphysik, University of Mainz, Mainz, D-55099, Germany); Azimov, Y. I.; Bantawa, K.(Kent State University, Kent, OH, 44242, USA); Beck, R.; Bekrenev, V. S.; H. Berghäuser; Braghieri, A.; Branford, D.; Briscoe, W. J.; Brudvik, J.

    2013-01-01

    The 12C (→γ ,pp) reaction has been studied in the photon energy range 200-450 MeV at the Mainz microtron MAMI-C, where linearly polarised photons were energy-tagged using the Glasgow-Mainz Tagged Photon Spectrometer and protons were detected in the Crystal Ball detector. The photon asymmetry Σ has been measured over a wider Eγ range than previous measurements. The strongest asymmetries were found at low missing energies where direct emission of nucleon pairs is expected. Cuts on the dif...

  10. Disintegration of {sup 12}C nuclei by 700–1500 MeV photons

    Nedorezov, V. [Institute for Nuclear Research, Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, 117312 Moscow (Russian Federation); D' Angelo, A.; Bartalini, O. [Dipartimento di Fisica – Università degli Studi di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); INFN – Sezione di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Bellini, V. [Dipartimento di Fisica – Università degli Studi di Catania, via Santa Sofia 64, I-95123 Catania (Italy); INFN – Sezione di Catania, via Santa Sofia 64, I-95123 Catania (Italy); Capogni, M. [Dipartimento di Fisica – Università degli Studi di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); INFN – Sezione di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Casano, L.E. [INFN – Sezione di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Castoldi, M. [Dipartimento di Fisica – Università degli Studi di Genova, via Dodecaneso 33, I-16146 Genova (Italy); Curciarello, F.; De Leo, V. [Dipartimento di Fisica e di Scienze della Terra, Università di Messina, salita Sperone 31, I-98166 Messina (Italy); INFN – Sezione di Catania, via Santa Sofia 64, I-95123 Catania (Italy); Didelez, J.-P. [IN2P3, Institut de Physique Nucléaire, Rue Georges Clemenceau, F-91406 Orsay (France); and others

    2015-08-15

    Disintegration of {sup 12}C nuclei by tagged photons of 700–1500 MeV energy at the GRAAL facility has been studied by means of the LAGRANγE detector with a wide angular acceptance. The energy and momentum distributions of produced neutrons and protons as well as their multiplicity distributions were measured and compared with corresponding distributions calculated with the RELDIS model based on the intranuclear cascade and Fermi break-up models. It was found that eight fragments are created on average once per about 100 disintegration events, while a complete fragmentation of {sup 12}C into 12 nucleons is observed typically only once per 2000 events. Measured multiplicity distributions of produced fragments are well described by the model. The measured total photoabsorption cross section on {sup 12}C in the same energy range is also reported.

  11. Characterization of γ-ray detectors using the photon tagger NEPTUN for energies up to 20 MeV

    Schnorrenberger, L.; Savran, D.; Glorius, J.; Lindenberg, K.; Löher, B.; Pietralla, N.; Sonnabend, K.

    2014-01-01

    A new setup for the characterization of γ-ray detectors has been installed at the NEPTUN photon tagger facility of TU Darmstadt. The tagging technique used at NEPTUN provides a quasi monoenergetic photon source up to about 20 MeV by selecting single γ-ray energies within a bremsstrahlung spectrum. The energy is freely selectable by changing the tagging condition. The detector response function (DRF) of γ-ray detectors for quasi monoenergetic incident photons can be measured. This allows to investigate DRFs of various photon detectors as a function of the incident γ-ray energy. Simulations of DRFs that are intensively used in the analysis of nuclear physics experiments can be tested and compared to experimental data. The experimental setup is presented and the measurement of the DRF of a large volume high-purity Germanium detector is described as an example.

  12. Characterization of γ-ray detectors using the photon tagger NEPTUN for energies up to 20 MeV

    Schnorrenberger, L., E-mail: schnorrenberger@ikp.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289 Darmstadt (Germany); Savran, D. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Glorius, J. [Institut für Angewandte Physik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Lindenberg, K. [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289 Darmstadt (Germany); Löher, B. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Pietralla, N. [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 9, D-64289 Darmstadt (Germany); Sonnabend, K. [Institut für Angewandte Physik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)

    2014-01-21

    A new setup for the characterization of γ-ray detectors has been installed at the NEPTUN photon tagger facility of TU Darmstadt. The tagging technique used at NEPTUN provides a quasi monoenergetic photon source up to about 20 MeV by selecting single γ-ray energies within a bremsstrahlung spectrum. The energy is freely selectable by changing the tagging condition. The detector response function (DRF) of γ-ray detectors for quasi monoenergetic incident photons can be measured. This allows to investigate DRFs of various photon detectors as a function of the incident γ-ray energy. Simulations of DRFs that are intensively used in the analysis of nuclear physics experiments can be tested and compared to experimental data. The experimental setup is presented and the measurement of the DRF of a large volume high-purity Germanium detector is described as an example.

  13. FLUKA and PENELOPE simulations of 10 keV to 10 MeV photons in LYSO and soft tissue

    Monte Carlo simulations of electromagnetic particle interactions and transport by FLUKA and PENELOPE were compared. 10 keV to 10 MeV incident photon beams impinged a LYSO crystal and a soft-tissue phantom. Central-axis as well as off-axis depth doses agreed within 1 s.d.; no systematic under- or over-estimate of the pulse height spectra was observed from 100 keV to 10 MeV for both materials, agreement was within 5%. Simulation of photon and electron transport and interactions at this level of precision and reliability is of significant impact, for instance, on treatment monitoring of hadrontherapy where a code like FLUKA is needed to simulate the full suite of particles and interactions (not just electromagnetic). At the interaction-by-interaction level, apart from known differences in condensed history techniques, two-quanta positron annihilation at rest was found to differ between the two codes. PENELOPE produced a 511 keV sharp line, whereas FLUKA produced visible acolinearity, a feature recently implemented to account for the momentum of shell electrons. - Highlights: • Monte Carlo simulations of electromagnetic particle interactions and transport by FLUKA and PENELOPE were compared. • 10 keV to 10 MeV incident photon beams impinged a LYSO crystal and a soft-tissue phantom. • The pulse height spectra, depth doses central-axis as well as off-axis were found to agree within statistical uncertainty; no systematic difference was observed

  14. Attenuation analysis of neutrons and photons generated by 52-MeV protons transmitted through shielding materials

    Attenuation of neutrons and photons transmitted through grahite, iron, water and ordinary concrete assemblies were studied using gold foils for thermal neutron and an NE-213 organic scintillation detector with an (n-γ) discrimination technique for spectral measurements. Source neutrons and photons were produced by 52-MeV proton bombardment of a 21.4-mm-thick graphite target placed in front of the assembly. The distributions of the light output from the scintillator were unfolded by the revised FERDO code. These experimental results were used as benchmark data on neutron and photon penetration by neutrons energy above 15MeV. Multigroup Monte Carlo, one-dimensional ANISN and two-dimensional DOT-3.5 transport calculations were performed with the DLC-58/HELLO group cross sections to compare with the measurement and to evaluate the cross sections. The DOT code was also used for the estimation of room-scattered neutron and photon contribution to the measured spectra. The results of the ANISN calculation of neutrons and the three-dimensional Monte Carlo calculation agreed with the experimental values except for high energy neutrons transmitted through water and graphite. The agreement of both calculations was well within the accuracy of 7% in the measured attenuation coefficients. For photons, the ANISN calculation gave >20% overestimation of the attenuation coefficients in the case of deep penetration through the medium for which the photon mean-free-path is shorter than that of neutrons, such as in iron and concrete. The result of the DOT calculation of neutrons down to thermal energy agreed well with the gold foil measurement in the absolute value. (author)

  15. Characterization of radiation damage caused by 23 MeV protons in Multi-Pixel Photon Counter (MPPC)

    Li, Zhengwei; Xu, Yupeng; Liu, Congzhan; Gu, Yudong; Xie, Fei; Li, Yanguo; Hu, Hongliang; Zhou, Xu; Lu, Xuefeng; Li, Xufang; Zhang, Shuo; Chang, Zhi; Zhang, Juan; Xu, Zhenling; Zhang, Yifei; Zhao, Jianling

    2016-06-01

    A automatic gain control system (AGC) is designed to continuously monitor and automatically control the gain of the phoswich detectors onboard the Hard X-ray Modulation Telescope (HXMT). It consists of a Am241 radioactive source and a photo-detector. The Am241 radioactive source is tagged within a plastic scintillator (BC440M). The scintillating photons produced by the decayed alpha particles from the radioactive source is readout by the photo-detector. The Multi-Pixel Photon Counter (MPPC) produced by Hamamatsu is used as the photo-detector for AGC. To verify the feasibility of its application in space environment, four MPPCs (S10362-33-050C) were irradiated by a beam of 23 MeV protons. The integrated proton fluence that exposed to the four MPPC samples are 1.0 ×108 p cm-2 , 2.0 ×108 p cm-2 , 4.0 ×108 p cm-2 and 1.0 ×1010 p cm-2 respectively. It is found that the increment leakage current of the MPPC samples caused by irradiation damage increase linearly with the integrated fluence. The pulse-height resolution of the MPPC has deteriorated hardly after irradiation. When irradiated up to 1.1 ×109cm-2 1 MeV equivalent neutrons, the MPPC completely lost its photon-counting capability but could still work as a photo-detector for AGC. The MPPC fails as a photo-detector for the AGC when the irradiated 1 MeV neutron equivalent fluences is up to 2.7 ×1010cm-2 .

  16. Quasifree Eta photoproduction on the proton and neutron of deuterium at photon energies up to 1150 MeV

    The present thesis describes the performance of the measurement of the quasi-free eta photoproduction on the neutron and on the proton of the deuterium for photon energies from the eta production threshold up to 1150 MeV. The ratio of the cross sections on the neutron to the cross sections on the proton could be determined to σn/σp=0.728±0.033. From this the isoscalar production amplitude, renormalized to the production amplitude on the proton, could be calculated with a value of 0.07±0.01

  17. Development of a vector and tensor polarized deuteron target and measurement of the target asymmetry in the photon-deuteron fission at 450 MeV and 650 MeV photon energy

    High vector- and tensor polarization was achieved with the newly-developed target material deuterated ammonia (ND3). For the dynamic nuclear polarization (DNP) the material was prepared by irradiation under liquid argon at 90 K with electrons of the Bonn 20 MeV injection Linac. At a magnetic field of 2.5 T and a temperature of 0.2 K we yielded a vector polarization of 0.44. The highest value 0.49 was obtained at 3.5 T after further 'in situ' irradiation during the measurement of spin observables of the deuteron. The corresponding values for the tensor polarization are 0.15 and 0.19. In addition, a method to enhance tensor polarization is introduced. This method bases on the saturation of RF-transitions in the deuteron spin system. The applicance to distinct deuteron spin-flip transitions in a single crystal is very effective. This has been demonstrated with promising results. At the Bonn 2.5 GeV Electron Synchrotron we have measured two angular distributions of the target asymmetry of the reaction γ + d↑ → p + n at photon energies of 450 MeV and 650 MeV and at proton-cm-angles between 250 and 1550. For one kinematical setting also the tensor asymmetry was measured. Proton and neutron were detected in coincidence. Our results are compared with recent analyses. (orig.)

  18. Application of the photon-fluence scaling theorem to absorbed dose calorimetry for bremsstrahlung peak energy >1.02 MeV

    Application of the 'photon fluence scaling theorem' allows the ionization chamber to be placed at points in media where the photon fluence is the same, hence eliminating problems with energy response. The theorem is applicable to Compton scattered photons. For photon energies greater than 1.02 MeV, pair production alters the photon fluence in such a way as to invalidate the scaling theorem. In this report the effect of pair production is examined, so that a correction may be applied to the photon fluence scaling theorem. This correction extends application of the theorem for bremsstrahlung spectra up to at least 25 MeV peak energy. 10 refs., 4 tabs., 1 fig

  19. FLUKA and PENELOPE simulations of 10keV to 10MeV photons in LYSO and soft tissue

    Chin, M P W; Fassò, A; Ferrari, A; Ortega, P G; Sala, P R

    2014-01-01

    Monte Carlo simulations of electromagnetic particle interactions and transport by FLUKA and PENELOPE were compared. 10 key to 10 MeV incident photon beams impinged a LYSO crystal and a soft-tissue phantom. Central-axis as well as off-axis depth doses agreed within 1 s.d.; no systematic under- or overestimate of the pulse height spectra was observed from 100 keV to 10 MeV for both materials, agreement was within 5\\%. Simulation of photon and electron transport and interactions at this level of precision and reliability is of significant impact, for instance, on treatment monitoring of hadrontherapy where a code like FLUKA is needed to simulate the full suite of particles and interactions (not just electromagnetic). At the interaction-by-interaction level, apart from known differences in condensed history techniques, two-quanta positron annihilation at rest was found to differ between the two codes. PENELOPE produced a 511 key sharp line, whereas FLUKA produced visible acolinearity, a feature recently implemen...

  20. The response of the new hypersensitive thermoluminescence materials to high energy photons (0.6-6.0 MeV)

    The energy dependence of two types of LiF:Mg,Cu,P (GR-200A from China, MCP-N from Poland) and one type of α-Al2O3:C from Russia has been studied in the range 0.6-6.0 MeV. For completion, standard LiF:Mg,Ti (TLD-100 from USA) was also tested with the same methods. All the irradiations were carried out in Metrological Facilities in Spain (CIEMAT) and Germany (PTB). A build-up experiment was performed using different thicknesses of PMMA placed at the front and back of detectors. Corrections from photon attenuation, build-up factor and dose enhancement have been calculated and compared for further discussion. The results for the hypersensitive phosphors show an agreement within 5% when the 6-7 MeV photon response is compared with the standard 137Cs calibration, while an under-response of 10% is observed for TLD-100. (author)

  1. Study of radiation damage caused by 23MeV protons on Multi-Pixel Photon Counter (MPPC)

    The automatic gain control system (AGC) is designed to continuously monitor and automatically control the gain of the phoswich detectors of the Hard X-ray Modulation Telescope (HXMT). It consists of a 241Am radioactive source distributed within a plastic scintillator (BC408) viewed by Multi-Pixel Photon Counter (MPPC). To verify the feasibility of application in space experiments, four MPPCs (S10362-33-050C) from Hamamatsu were irradiated using a beam of 23MeV protons with flux 1.0×108pcm-2, 2.0×108pcm-2, 4.0×108pcm-2 and 1.0×1010pcm-2. The leakage current of irradiated MPPC samples is found to increase linearly with total dose due to radiation damage. The device has completely lost its photon-counting capability when irradiated up to 13.6Gy. The pulse-height resolution has deteriorated hardly after irradiation and couldn't work with more than 450Gy, where the measured sample has been illuminated with a few hundred photons by the 241Am radioactive source. (author)

  2. MeV- and Sub-MeV-photon Sources Based on Compton Backscattering at Spring-8 and KPSI-JAEA

    K.Kawase; M.Kando; T.Hayakawa; I.Daito; S.Kondo; T.Homma; T.Kameshima; H.Kotaki; L.Chen; Y.Fukuda; A.Faenov; Shizuma; S.V.Bulanov; T.Kimura; T.Tajima; M.Shoji; S.Suzuki; K.Tamura; H.Ohkuma; Y.Arimoto; T.Yorita; M.Fujiwara; S.Okajima

    2009-01-01

    Recently we have constructed two facilities for generating photon beams in the MeV and sub-MeV energy regions by means of the Compton backscattering with a laser and an electron beam at SPring-8 and at Kansai Photon Science Institute of Japan Atomic Energy Agency(KPSIJAEA).The MeV-photon source at SPring-8 consists of a continuous-wave optically-pumped far infrared laser with a wavelength of 118.8 μm and an 8 GeV stored electron beam.Present MeV-photon flux is estimated to be 1.3×10~3 photons/s.On the other hand,the sub-MeV-photon source at KPSI-JAEA consists of a pulse Nd:YAG laser with a wavelength of 1 064 nm and a 150 MeV electron beam accelerated by microtron.In the first trial of the photon production in this source,backscattered photon flux is estimated to be 20 photons/pulse.Both the Compton backscattered photon sources have possibilities to be used for new tools in various fields such as nuclear physics,materials science,and astronomy.

  3. Fissility of Bi, Pb, Au, Pt, W, Ta, V, and Ti nuclei measured with 100 MeV compton back-scattered photons

    Photofission cross sections of 209 Bi, nat Pb, 197 Au, nat Pt, nat W, 181 Ta, 51 V, and nat Ti nuclei have been measured at an incident photon energy of 100 MeV using monochromatic photons produced by Compton backscattering at the ROKK-1M facility (BINP, Novosibirsk). Detection of fission fragments has been performed by means of Makrofol track-etch detectors in close contact with metallic foils of the target elements. The values of fissility at 100 MeV deduced for the targets under investigation are found to range between 10-4 and 10-2. The present results show consistency with the fissility trends calculated for 69- and 600-MeV monoenergetic photons using a formalism based on the current two-step model for intermediate-energy photofission reactions. (author). 39 refs., 4 figs., 3 tabs

  4. Dilepton and double-photon production in proton-proton scattering at 190 MeV

    Caplar, R.; Bacelar, J.C.S; Castelijns, R.J.J.; Ermisch, K.; Gasparic, I.; Harakeh, M.N.; Kalantar-Nayestanaki, N.; Kis, M.; Löhner, H.; Mahjour Shafiei, M.

    2004-01-01

    The first high-statistics measurement of dilepton and double-photon yields in proton-proton scattering below the pion threshold has been performed. The data obtained allow a detailed study of off-shell effects in the proton-proton interaction.

  5. Astronomical telescope for photons-gamma rays of low energy (approximately 4 MeV using the difference method like a Venetian blind

    de Aguiar, O. D.; Martin, I. M.

    1980-07-01

    A description of a gamma ray telescope, which is sensitive to photons in the energy range of 3 - 10 MeV is presented. Collimation was provided by a passive shield which functioned somewhat like a 'venetian blind' to block the signal from one of the detectors. Signal subtraction techniques were used to obtain the desired information.

  6. The thermoluminescence characteristics and the glow curves of Thulium doped silica fiber exposed to 10 MV photon and 21 MeV electron radiation

    The thermoluminescence (TL) glow curves and kinetics parameters of Thulium (Tm) doped silica cylindrical fibers (CF) are presented. A linear accelerator (LINAC) was used to deliver high-energy radiation of 21 MeV electrons and 10 MV photons. The CFs were irradiated in the dose range of 0.2–10 Gy. The experimental glow curve data was reconstructed by using WinREMS. The WinGCF software was used for the kinetic parameters evaluation. The TL sensitivity of Tm-doped silica CF is about 2 times higher as compared to pure silica CF. Tm-doped silica CF seems to be more sensitive to 21 MeV electrons than to 10 MV photons. Surprisingly, no supralinearity was displayed and a sub-linear response of Tm-doped silica CF was observed within the analyzed dose range for both 21 MeV electrons and 10 MV photons. The Tm-doped silica CF glow curve consists of 5 individual glow peaks. The Ea of peak 4 and peak 5 was highly dependent on dose when irradiated with photons. We also noticed that the electron radiation (21 MeV) caused a shift of glow peak by 7–13 °C to the higher temperature region compared with photons radiation (10 MV). Our Tm-doped fibers seem to give high TL response after 21 MeV electrons, which gives around 2 times higher peak integral as compared with 10 MV photon radiation. We concluded that peak 4 is the first-order kinetic peak and can be used as the main dosimetric peak of Tm-doped silica CF. - Highlights: • A sub-linear response of Tm doped silica CF was measured at dose range of 0.2–10 Gy. • The TL sensitivity of Tm doped silica CF is 2 times higher as compared to pure silica CF. • Tm-doped silica CF glow curve consists of 5 individual glow peaks. • The glow peak area and peak height of Tm-doped silica CF are highly dependent on dose. • The kinetics parameters are highly dependent on dose

  7. Charged particle equilibrium corrections for photon sources from 400 keV to 1.4 MeV

    Vasudevan, Latha

    Lack of charged particle equilibrium (CPE) has practical importance in radiological health protection, in nuclear medicine, and radiobiology where small radioactive point sources irradiate the human body accidentally or may be introduced into the body for diagnostic, therapeutic, or analytical purposes. The absorbed dose under CPE is readily calculated from knowledge of the photon energy fluence and mass-absorption coefficient of the material. When estimating absorbed dose rates at points close to the source, the primary radiation field varies appreciably over the region within the range of secondary particles. Under such conditions, CPE does not exist and prediction of absorbed dose becomes difficult. However, if one applies correction factors for non-CPE conditions, absorbed dose rates can be calculated fairly easily. In this dissertation, a CPE model was developed for non-CPE conditions to predict the fraction of charged particle equilibrium (GammaCPE) attained in a water medium for point sources of energies in the range from 400 keV to 1.4 MeV using EGS4-DOSRZ Monte Carlo calculation. A new methodology to calculate absorbed dose and kerma along the central axis of the cylindrical phantom was presented and the results were found to be in excellent agreement with published values. In order to corroborate with the EGS4-DOSRZ calculation, another model based on the Klein-Nishina single scattering cross section was developed to quantify the GammaCPE attained in water for point sources. A CPE path length coefficient (mu cm-1) was found for each photon energy and compared with published values. This coefficient was used to determine dose rates averaged over 1 cm2 at depths that are of interest in skin dose exposures. Experimental measurements of CPE were carried out for a Co-60 point source using GAFCHROMICRTM MD-55 film (1990) as the dosimetry media. The films were read using a document scanner. Dose rates obtained using the scanner method were compared with those

  8. Quasifree Eta photoproduction on the proton and neutron of deuterium at photon energies up to 1150 MeV; Quasifreie Eta-Photoproduktion am Proton und Neutron des Deuteriums bei Photonenergien bis 1150 MeV

    Krebeck, M.

    1995-12-31

    The present thesis describes the performance of the measurement of the quasi-free eta photoproduction on the neutron and on the proton of the deuterium for photon energies from the eta production threshold up to 1150 MeV. The ratio of the cross sections on the neutron to the cross sections on the proton could be determined to {sigma}{sub n}/{sigma}{sub p}=0.728{+-}0.033. From this the isoscalar production amplitude, renormalized to the production amplitude on the proton, could be calculated with a value of 0.07{+-}0.01.

  9. Studies on effective atomic numbers for photon energy absorption and electron density of some narcotic drugs in the energy range 1 keV-20 MeV

    Gounhalli, Shivraj G.; Shantappa, Anil; Hanagodimath, S. M.

    2013-04-01

    Effective atomic numbers for photon energy absorption ZPEA,eff, photon interaction ZPI,eff and for electron density Nel, have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for narcotic drugs, such as Heroin (H), Cocaine (CO), Caffeine (CA), Tetrahydrocannabinol (THC), Cannabinol (CBD), Tetrahydrocannabivarin (THCV). The ZPEA,eff, ZPI,eff and Nel values have been found to change with energy and composition of the narcotic drugs. The energy dependence ZPEA,eff, ZPI,eff and Nel is shown graphically. The maximum difference between the values of ZPEA,eff, and ZPI,eff occurs at 30 keV and the significant difference of 2 to 33% for the energy region 5-100 keV for all drugs. The reason for these differences is discussed.

  10. Measurement of the differential cross sections of the reaction γ+p → π++n at mean production angles and photon energies from 735 to 2005 MeV and parametrization of the c.m. angular distributions in the energy range from 300 to 1985 MeV

    In this experiment the differential cross sections of the reaction γp → π+n in the photon energy interval from 735 MeV to 2005 MeV under the pion laboratory angle of 330 and 60.80 were measured. (orig./HSI)

  11. Estimation of effective atomic numbers of some solutions for photon energy absorption in the energy region 0.2-1.5 MeV: An alternative method

    Kurudirek, Murat

    2011-12-01

    The effective atomic numbers (ZPEAeff), which are used to describe the composite materials in terms of equivalent elements, have been estimated in some solutions for photon energy absorption in the energy region 0.2-1.5 MeV. Since the mass energy absorption (μen/ρ) and mass attenuation coefficients (μ/ρ) remain more or less the same for any given material in the photon energy region 0.2-1.5 MeV where Compton scattering is the main dominant photon interaction process, semi-empirical relations including both μen/ρ and μ/ρ have been constituted as a function of energy. These parameters were then used to obtain ZPEAeff with the help of a Z-wise interpolation procedure. The results were compared with the experimental as well as other theoretical estimations wherever possible. Consequently, the present method is found to be readily applicable to the given solutions in order to estimate accurate values of ZPEAeff for which it is not possible to directly obtain experimentally using the conventional gamma spectrometry system.

  12. Estimation of effective atomic numbers of some solutions for photon energy absorption in the energy region 0.2-1.5 MeV: An alternative method

    The effective atomic numbers (ZPEAeff), which are used to describe the composite materials in terms of equivalent elements, have been estimated in some solutions for photon energy absorption in the energy region 0.2-1.5 MeV. Since the mass energy absorption (μen/ρ) and mass attenuation coefficients (μ/ρ) remain more or less the same for any given material in the photon energy region 0.2-1.5 MeV where Compton scattering is the main dominant photon interaction process, semi-empirical relations including both μen/ρ and μ/ρ have been constituted as a function of energy. These parameters were then used to obtain ZPEAeff with the help of a Z-wise interpolation procedure. The results were compared with the experimental as well as other theoretical estimations wherever possible. Consequently, the present method is found to be readily applicable to the given solutions in order to estimate accurate values of ZPEAeff for which it is not possible to directly obtain experimentally using the conventional gamma spectrometry system.

  13. Photon activation analysis of the scraper in a 200-MeV electron accelerator using gamma-spectrometry depth profiling

    Lijuan, He; Guobing, Yu; Guangyi, Ren; Zongjin, Duan

    2014-01-01

    For a high energy electron facility, the estimates of induced radioactivity in materials are of major importance to keep exposure to personnel and to the environment as low as reasonably achievable. In addition, an accurate prediction of induced radioactivity is also essential for the design, operation and decommissioning of a high energy electron linear accelerator. The research of induced radioactivity focuses on the photonuclear reaction, whose giant resonance response in the copper is ranging from 10 MeV to 28 MeV. The 200 MeV electron linac of NSRL is one of the earliest high-energy electron linear accelerators in P. R. China. The electrons are accelerated to 200 MeV by five acceleration tubes and collimated by the scrapers made of copper. At present, it is the first retired high-energy electron linear accelerator in domestic. Its decommissioning provides an efficient way for the induced radioactivity research of such accelerators, and is a matter of great significance to the accumulation of the induced ...

  14. Photon asymmetry measurements of $\\overrightarrow{\\gamma} \\mathrm{p} \\rightarrow \\pi^{0} \\mathrm{p}$ for E$_{\\gamma}$=320$-$650 MeV

    Gardner, S; Sikora, M H; Wunderlich, Y; Abt, S; Achenbach, P; Afzal, F; Aguar-Bartolome, P; Ahmed, Z; Annand, J R M; Arends, H J; Bantawa, K; Bashkanov, M; Beck, R; Biroth, M; Borisov, N S; Braghieri, A; Briscoe, W J; Cherepnya, S; Cividini, F; Costanza, S; Collicott, C; Demissie, B T; Denig, A; Dieterle, M; Downie, E J; Drexler, P; Ferretti-Bondy, M I; Filkov, L V; Glazier, D I; Garni, S; Gradl, W; Günther, M; Gurevich, G M; Hamilton, D; Heid, E; Hornidge, D; Huber, G M; Jahn, O; Jude, T C; Käser, A; Kay, S; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Linturi, J M; Lisin, V; Livingston, K; Lutterer, S; MacGregor, I J D; Macrae, R; Mancell, J; Manley, D M; Martel, P P; McGeorge, J C; McNicoll, E F; Middleton, D G; Miskimen, R; Mullen, C; Mushkarenkov, A; Neganov, A B; Neiser, A; Nikolaev, A; Oberle, M; Ostrick, M; Owens, R O; Otte, P B; Oussena, B; Paudyal, D; Pedroni, P; Polonski, A; Prakhov, S; Rajabi, A; Robinson, J; Rosner, G; Rostomyan, T; Sarty, A; Schumann, S; Sokhoyan, V; Spieker, K; Steffen, O; Sfienti, C; Strakovsky, I I; Strandberg, B; Strub, Th; Supek, I; Tarbert, C M; Thiel, A; Thiel, M; Thomas, A; Unverzagt, M; Usov, Yu A; Watts, D P; Werthmüller, D; Wettig, J; Wolfes, M; Witthauer, L; Zana, L

    2016-01-01

    High statistics measurements of the photon asymmetry $\\mathrm{\\Sigma}$ for the $\\overrightarrow{\\gamma}$p$\\rightarrow\\pi^{0}$p reaction have been made in the center of mass energy range W=1214-1450 MeV. The data were measured with the MAMI A2 real photon beam and Crystal Ball/TAPS detector systems in Mainz, Germany. The results significantly improve the existing world data and are shown to be in good agreement with previous measurements, and with the MAID, SAID, and Bonn-Gatchina predictions. We have also combined the photon asymmetry results with recent cross-section measurements from Mainz to calculate the profile functions, $\\check{\\mathrm{\\Sigma}}$ (= $\\sigma_{0}\\mathrm{\\Sigma}$), and perform a moment analysis. Comparison with calculations from the Bonn-Gatchina model shows that the precision of the data is good enough to further constrain the higher partial waves, and there is an indication of interference between the very small $F$-waves and the $N(1520) 3/2^{-}$ and $N(1535) 1/2^{-}$ resonances.

  15. Measurement of proton polarization in the deuteron photodisintegration reaction on the linearly polarized photon beam in the energy range Eγ=290-420 MeV at angle Θpx=65 deg cms

    The results of measurement of proton polarization in the reaction plane (Pxz) and in the plane (Py) perpendicular to it, in the deuteron photodisintegration reaction in the photon energy range from 290 MeV to 420 MeV at proton escape angle in cms Θpx=65 deg, are presented. The results are compared with the predictions of theoretical calculations of the gradient-invariant model with account of dibaryon resonances. 6 refs.; 2 figs.; 1 tab

  16. Ionization chamber with build-up cup spectral sensitivity to megavoltage (0.5-20 MeV) photon fluences in free air

    In-air measurements of photon beam properties, used in radiation therapy, is common practice for determining radiation output dependence from the field size, known as head scatter factors (HSF). PMMA and brass build-up caps are most popular miniphantoms for providing electron equilibrium. Discrepancies up to 2% in HSF measurements by different combinations of detectors and equilibrium caps have been published. One of the main reasons of those discrepancies is the detector system spectral sensitivity and differences in primary and scatter radiation spectra. In the light of new model based dose calculation methods direct radiation fluence measurement is of great interest. So, understanding of detector spectral sensitivity is important task for modern dosimetry of radiation therapy. In the present study Monte Carlo (MC) method was employed to calculate ionization chamber response to monoenergetic photon fluences, normalized to water kerma units. Simulation was done using EGS4 package. Electron transport was performed with ESTEPE equal to 4%. PEGS cross sections were generated for maximal energy 20 MeV with cutoff kinetic energy 10 KeV both for photons and electrons. Scanditronix RK-05 ionization chamber was chosen as a prototype. Eight cylindrical miniphantoms, representing four materials (PMMA, Al, Cu, Pb) and two front wall thickness, were simulated. Results are presented. Miniphantom front wall thicknesses in each case are shown in the figure. Diameter depends on the material and equal respectively: PMMA - 4, Al - 2.5, Cu - 1.5, and PB - 1.5 cm. Ionization chamber outer diameter is equal to 0.7 cm. Detector sensitivity has considerable energy dependence. Two effects explain it. First is the radiation attenuation in the miniphantom. Second is pair production, which dominates in high atomic number miniphantoms for energies above 5 MeV. Depending on the miniphantom material detector response changes from 1.5 to 5 times in the energy range from 0.5 to 20 MeV. Correct

  17. Photon-induced multiple particle emissions of 90Zr and natZr from 10 to 140 MeV

    A comprehensive analysis of electrodisintegration yields of protons on 90Zr is proposed taking into account the giant dipole resonance, isovector giant quadrupole resonance (IVGQR), and quasideuteron contributions to the total photoabsorption cross section from 10 to 140 MeV. The calculation applies the MCMC intranuclear cascade to address the direct and pre-equilibrium emissions and another Monte Carlo-based algorithm to describe the evaporation step. The final results of the total photoabsorption cross section for 90Zr and relevant decay channels are obtained by fitting the (e,p) measurements from the National Bureau of Standards and show that multiple proton emissions dominate the photonuclear reactions at higher energies. These results provide a consistent explanation for the exotic and steady increase of the (e,p) yield and also a strong evidence of a IVGQR with a strength parameter compatible with the E2 energy-weighted sum rule. The inclusive photoneutron cross sections for 90Zr and natZr, derived from these results and normalized with the (e,p) data, are in agreement within 10% with both Livermore and Saclay data up to 140 MeV

  18. Determination of fission product yields in the 14 MeV photon (Bremsstrahlung) induced fission of 232Th

    The cumulative yields of various fission products in the 232Th(γ,f) with end-point Bremsstrahlung energy of 14 MeV having have been determined using off-line γ-ray spectrometric technique. The end-point Bremsstrahlung energy of 14 MeV was generated by impinging the electron beam on a solid graphite beam dump of the 20 electron LINAC (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany. From the cumulative fission yields, the mass chain yields were obtained by using charge distribution correction of medium energy. The fine structure in the mass yield distribution was interpreted from the point of nuclear structure effect such as shell closure proximity and even-odd effect. The mass yield distribution in 232Th(γ,f) is triple humped unlike 238U(γ,f), where it is double humped. This different behaviour in between 232Th* and 238U* was explained from the point of different potential energy surfaces between two systems. (author)

  19. Experimental measurement of the photon efficiency of a 4 mm thick NE 102 A scintillator for 14 MeV neutrons

    The purpose of this experiment is to determine the photon efficiency of a 4 mm thick NE 102 A neutron pinhole imaging system. Neutrons are produced by 1.5 MeV deuterons (accelerated in a VAN DE GRAAFF accelerator located at C.E.A.-Centre d'Etudes de Bruyeres le Chatel) interacting on a gaseous tritium target. A numerical calculation enables to estimate the energy deposition from a neutron in the scintillator. The photoconversion efficiency of the NE 102 A scintillator is determined. In order to confirm the results obtained with the neutrons, a complementary experiment has been made on the NE 102 A scintillator with a 10000 curies Co60 gamma source. The values obtained for the photoconversion efficiency are respectively (4.23 +- 0.42)% for neutrons and (4.16 +- 0.42)% for gamma

  20. Neutron interrogation of actinides with a 17 MeV electron accelerator and first results from photon and neutron interrogation non-simultaneous measurements combination

    Sari, A., E-mail: adrien.sari@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Carrel, F.; Lainé, F. [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, 91191 Gif-sur-Yvette Cedex (France); Lyoussi, A. [CEA, DEN, 13108 Saint-Paul-Lez-Durance Cedex (France)

    2013-10-01

    In this article, we demonstrate the feasibility of neutron interrogation using the conversion target of a 17 MeV linear electron accelerator as a neutron generator. Signals from prompt neutrons, delayed neutrons, and delayed gamma-rays, emitted by both uranium and plutonium samples were analyzed. First results from photon and neutron interrogation non-simultaneous measurements combination are also reported in this paper. Feasibility of this technique is shown in the frame of the measurement of uranium enrichment. The latter was carried out by combining detection of prompt neutrons from thermal fission and delayed neutrons from photofission, and by combining delayed gamma-rays from thermal fission and delayed gamma-rays from photofission.

  1. Air kerma to personal dose equivalent conversion factors for ICRU and ISO recommended slab phantoms for photons from 20 keV to 1 MeV

    The present report summarizes the studies carried out at ENEA-AMB-PRO-IRP (Institute for Radiation Protection) that were addressed to the determination of air kerma to personal dose equivalent conversion coefficients for two practical phantoms as proposed by ICRU (International Commission for Radiation Units and Measurements) and by ISO (International Standard Organization) for photon personal dosimeters' calibration procedure. The analyses, developed using the MCNP Monte Carlo code, were mainly aimed at establishing which of the two proposed phantoms better approximates the ICRU theoretical one. Furthermore a complete tabulation of the conversion coefficients is supplied for monoenergetic photon beams from 20 keV to 1 MeV as well as for the two ISO X-ray reference series Wide Spectrum and Narrow Spectrum. The study has been performed in the framework of the CEC Contract F13P-CT92-0064 'The Measurement of the Spectral and Angular Distribution of External Radiations in Workplace and Implications for Personal Dosimetry

  2. Comprehensive study on energy absorption buildup factors and exposure buildup factors for photon energy 0.015 to 15 MeV up to 40 mfp penetration depth for gel dosimeters

    The gel dosimeter comprises of phantom, dosimetric material and three-D spatial dose distribution has advantages over one- and two-D dosimeters. Energy absorption buildup factor (EABF) and exposure buildup factor (EBF) values of sixteen gel dosimeters have been computed for photon energy 0.015 to 15 MeV up to 40 mfp (mean free path) penetration depths. Kerma of the gel dosimeters were computed for photon energy 1 keV to 20 MeV. The water and PMMA phantom equivalence of the gel dosimeters was evaluated using EABF, and large difference was noted below 1 MeV photon energy. This study should be useful for estimation of effective dose to the human organs and simulation of the dose for radiation therapy and various medical applications. - Highlights: • EABF and EBF values of 16 gel dosimeters were computed using GP fitting method. • Water and PMMA equivalence was investigated using EABF. • Ratio of EABF of BANG1 to water and PMMA is close to unity above 1 MeV. • Photon kerma relative to air of PRESAGE shows a peak at 40 keV

  3. Mass attenuation and mass energy absorption coefficients for 10 keV to 10 MeV photons; Coefficients d'attenuation massique et d'absorption massique en energie pour les photons de 10 keV a 10 MeV

    Joffre, H.; Pages, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    In this report are given the elements allowing the definition of the values of mass attenuation coefficients and mass energy absorption coefficients for some elements and mixtures, necessary for the study of tissue equivalent materials, for photons in the energy range 10 keV to 10 MeV. After a short reminding of the definitions of the two coefficients, follows, in table form, a compilation of these coefficients, as a function of energy, for simple elements, for certain mineral compounds, organic compounds, gases and particularly of soft tissues. (author) [French] Dans ce rapport, sont donnes les elements permettant de determiner les valeurs des coefficients d'attenuation massique et d'absorption massique en energie pour certains elements et melanges necessaires a l'etude des materiaux equivalents aux tissus pour les photons dans le domaine d'energie allant de 10 keV a 10 MeV. Apres un bref rappel des definitions des deux coefficients, suit, sous forme de tableaux, un recueil de ces coefficients, en fonction de l'energie, pour les elements simples, certains composes mineraux, composes organiques, gaz, et, particulierement, pour les tissus mous. (auteur)

  4. Photonics

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov

  5. Photonics

    Andrews, David L

    2015-01-01

    This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol

  6. Photonics

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry

  7. Photonics

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas

  8. Gamma Cherenkov-transition radiation of high energy electrons and methods for the measurement of the refractive index of MeV photons using total internal and external reflections (Invited talk)

    It is given a review of the theoretical works showing that gamma ray Cherenkov-transition radiation (GCTR) is produced in some materials the refractive index of which in gamma region is greater than 1 according to the famous results of [1]. Since there are some published doubts [2] on the theoretical results of [1], and taking into account the difficulties of the experiment [1], in order to confirm or decline the results [1] it is proposed to study experimentally GCTR and an experimental method for the measurement of refractive index of MeV photons.

  9. Energy dependent response of the Fricke gel dosimeter prepared with 270 Bloom gelatine for photons in the energy range 13.93 keV-6 MeV

    Cavinato, C.C. [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP (Brazil); Campos, L.L., E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, 05508-000 Sao Paulo, SP (Brazil)

    2010-07-21

    The spectrophotometric energy dependent response to photons with effective energies between 13.93 keV and 6 MeV of the Fricke xylenol gel (FXG) dosimeter developed at IPEN, prepared using 270 Bloom gelatine, was evaluated in order to verify the possible dosimeter application in other medicine areas in addition to radiosurgery, for example, breast radiotherapy and blood bags radiosterilization. Other dosimetric characteristics were also evaluated. The obtained results indicate that the FXG dosimeter can contribute to dosimetry in different medical application areas including magnetic resonance imaging (MRI) evaluation technique that permits three-dimensional (3D) dose distribution evaluation.

  10. Energy dependent response of the Fricke gel dosimeter prepared with 270 Bloom gelatine for photons in the energy range 13.93 keV-6 MeV

    The spectrophotometric energy dependent response to photons with effective energies between 13.93 keV and 6 MeV of the Fricke xylenol gel (FXG) dosimeter developed at IPEN, prepared using 270 Bloom gelatine, was evaluated in order to verify the possible dosimeter application in other medicine areas in addition to radiosurgery, for example, breast radiotherapy and blood bags radiosterilization. Other dosimetric characteristics were also evaluated. The obtained results indicate that the FXG dosimeter can contribute to dosimetry in different medical application areas including magnetic resonance imaging (MRI) evaluation technique that permits three-dimensional (3D) dose distribution evaluation.

  11. Caractérisation et optimisation de sources d'électrons et de photons produites par laser dans les domaines du keV et du MeV

    Bonnet, Thomas

    2013-01-01

    This work takes place in the framework of the characterization and theoptimization of laser-driven electron and photon sources. With the goal of usingthese sources for nuclear physics experiments, we focused on 2 energy ranges:one around a few MeV and the other around a few tens of keV. The first partof this work is thus dedicated to the study of detectors routinely used forthe characterization of laser-driven particle sources: Imaging Plates. A modelhas been developed and is fitted to experi...

  12. Tables and graphs of photon-interaction cross sections from 0.1 keV to 100 MeV derived from the LLL evaluated-nuclear-data library

    Energy-dependent evaluated photon interaction cross sections and related parameters are presented for elements H through Cf(Z = 1 to 98). Data are given over the energy range from 0.1 keV to 100 MeV. The related parameters include form factors and average energy deposits per collision (with and without fluorescence). Fluorescence information is given for all atomic shells that can emit a photon with a kinetic energy of 0.1 keV or more. In addition, the following macroscopic properties are given: total mean free path and energy deposit per centimeter. This information is derived from the Livermore Evaluated-Nuclear-Data Library (ENDL) as of October 1978

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

    Ten radionuclides, including isomers, from 172Ta to 180Ta and 180mHf 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 175,176,180Ta and 180mHf. Those obtained for the three Ta isotopes agree with previously reported values. For 180mHf, the present measurements resulted in a half life determination of 6.05±0.06 hr, or about 10% longer than the currently adopted value for this half life

  14. Tests of a Compton imaging prototype in a monoenergetic 4.44 MeV photon field—a benchmark setup for prompt gamma-ray imaging devices

    Golnik, C.; Bemmerer, D.; Enghardt, W.; Fiedler, F.; Hueso-González, F.; Pausch, G.; Römer, K.; Rohling, H.; Schöne, S.; Wagner, L.; Kormoll, T.

    2016-06-01

    The finite range of a proton beam in tissue opens new vistas for the delivery of a highly conformal dose distribution in radiotherapy. However, the actual particle range, and therefore the accurate dose deposition, is sensitive to the tissue composition in the proton path. Range uncertainties, resulting from limited knowledge of this tissue composition or positioning errors, are accounted for in the form of safety margins. Thus, the unverified particle range constrains the principle benefit of proton therapy. Detecting prompt γ-rays, a side product of proton-tissue interaction, aims at an on-line and non-invasive monitoring of the particle range, and therefore towards exploiting the potential of proton therapy. Compton imaging of the spatial prompt γ-ray emission is a promising measurement approach. Prompt γ-rays exhibit emission energies of several MeV. Hence, common radioactive sources cannot provide the energy range a prompt γ-ray imaging device must be designed for. In this work a benchmark measurement-setup for the production of a localized, monoenergetic 4.44 MeV γ-ray source is introduced. At the Tandetron accelerator at the HZDR, the proton-capture resonance reaction 15N(p,α γ4.439)12C is utilized. This reaction provides the same nuclear de-excitation (and γ-ray emission) occurrent as an intense prompt γ-ray line in proton therapy. The emission yield is quantitatively described. A two-stage Compton imaging device, dedicated for prompt γ-ray imaging, is tested at the setup exemplarily. Besides successful imaging tests, the detection efficiency of the prototype at 4.44 MeV is derived from the measured data. Combining this efficiency with the emission yield for prompt γ-rays, the number of valid Compton events, induced by γ-rays in the energy region around 4.44 MeV, is estimated for the prototype being implemented in a therapeutic treatment scenario. As a consequence, the detection efficiency turns out to be a key parameter for prompt

  15. First Measurements of Spin-Dependent Double-Differential Cross Sections and the GDH Integrand from \\vec{^3He}(\\vec{\\gamma},n)pp at Incident Photon Energies of 12.8 and 14.7 MeV

    Laskaris, G; Lalremruata, B; Ye, Q J; Ahmed, M W; Averett, T; Deltuva, A; Dutta, D; Fonseca, A C; Gao, H; Golak, J; Huang, M; Karwowski, H J; Mueller, J M; Myers, L S; Peng, C; Perdue, B A; Qian, X; Sauer, P U; Skibiński, R; Tompkins, S Stave J R; Weller, H R; Witała, H; Wu, Y K; Zhang, Y; Zheng, W

    2013-01-01

    The first measurement of the three-body photodisintegration of longitudinally-polarized ^3He with a circularly-polarized \\gamma-ray beam was carried out at the High Intensity \\gamma-ray Source (HI\\gamma S) facility located at Triangle Universities Nuclear Laboratory (TUNL). The spin-dependent double-differential cross sections and the contributions from the three-body photodisintegration to the ^3He GDH integrand are presented and compared with state-of-the-art three-body calculations at the incident photon energies of 12.8 and 14.7 MeV. The data reveal the importance of including the Coulomb interaction between protons in three-body calculations.

  16. The S.C.I.C. detector: an unconventional design for the detection of low-energy (200-300)MeV photons

    The simulated performances of a non-homogeneous e.m. calorimeter based on a 5 X tracking section using CsI(Tl) fibres, followed by a 10 X0Pb-SCIFI head-on back section are reported. The study shows that such a technique is quite promising for the high-efficiency detection of photons in the energy range of interest at a φ-factory machine

  17. Fluence-to-effective dose conversion coefficients from a Saudi population based phantom for monoenergetic photon beams from 10 keV to 20 MeV

    Fluence-to-dose conversion coefficients are important quantities for radiation protection, derived from Monte Carlo simulations of the radiation particles through a stylised phantom or voxel based phantoms. The voxel phantoms have been developed for many ethnic groups for their accurate reflection of the anatomy. In this study, we used the Monte Carlo code MCNPX to calculate the photon fluence-to-effective dose conversion coefficients with a voxel phantom based on the Saudi Arabian male population. Six irradiation geometries, anterior–posterior (AP), posterior–anterior (PA), left lateral (LLAT), right lateral (RLAT), rotational (ROT) and isotropic (ISO) were simulated for monoenergetic photon beams from 10 keV to 20 MeV. We compared the coefficients with the reference values in ICRP Publication 116. The coefficients in the AP and PA geometries match the reference values to 9% and 12% on average as measured by root mean square while those in the LLAT, RLAT ROT and ISO geometries differ, mostly below, from the reference by 23, 22, 15 and 16%, respectively. The torso of the Saudi phantom is wider than the ICRP reference male phantom and likely to cause more attenuation to the lateral beam. The ICRP reference coefficients serve well for the Saudi male population as conservative estimations for the purpose of radiation protection. (paper)

  18. Design of the experimental apparatus to obtain a thermal neutron beam, intermediate-energy neutrons (2-144 keV) and high-energy photons (6 MeV) by means of the TRIGA reactor at the ENEA Casaccia center

    Laitano, R F

    1987-01-01

    Design of the experimental apparatus to obtain a thermal neutron beam, intermediate-energy neutrons (2-144 keV) and high-energy photons (6 MeV) by means of the TRIGA reactor at the ENEA Casaccia center

  19. High energy photon response

    This study examines the response of the Hanford 4-chip and 5-chip dosimeter to high energy photons. The dose response of the Hanford Multipurpose Personnel Diometer (HMPD) to photons with energies greater than 0.65 MeV has been evaluated relative to the dose produced by photons from a 60Co. source. The penetrating dose determined with the HMPD is compared to the 1 cm depth dose in tissue measured with an extrapolation chamber. The results of the study indicate that the HMPD can be used to estimate the 1 cm depth dose in tissue from photons with energies between 0.65 MeV and 3.0 MeV to within an accuracy of 15%. However, the 1 cm depth dose is underestimated by 38% when the dosimeter is irradiated in a beam of very high energy photons produced by bombarding a tungsten target with 25 MeV electrons

  20. Technical Note: Influence of the phantom material on the absorbed-dose energy dependence of the EBT3 radiochromic film for photons in the energy range 3 keV–18 MeV

    Purpose: Water is the reference medium for radiation therapy dosimetry, but for film dosimetry it is more practical to use a solid phantom. As the composition of solid phantoms differs from that of water, the energy dependence of film exposed within solid phantoms may also differ. The energy dependence of a radiochromic film for a given beam quality Q (energy for monoenergetic beams) has two components: the intrinsic energy dependence and the absorbed-dose energy dependence f(Q), the latter of which can be calculated through a Monte Carlo simulation of radiation transport. The authors used Monte Carlo simulations to study the influence of the phantom material on the f(Q) of the EBT3 radiochromic film (Ashland Specialty Ingredients, Wayne, NJ) for photon beams with energies between 3 keV and 18 MeV. Methods: All simulations were carried out with the general-purpose Monte Carlo code PENELOPE 2011. The geometrical model consisted of a cylindrical phantom, with the film positioned at different depths depending on the initial photon energy. The authors simulated monoenergetic parallel photon beams and x-ray beams from a superficial therapy system. To validate their choice of simulation parameters, they also calculated f(Q) for older film models, EBT and EBT2, comparing with published results. In addition to water, they calculated f(Q) of the EBT3 film for solid phantom materials commonly used for film dosimetry: RW1 and RW3 (PTW-Freiburg, Freiburg, Germany), Solid Water (Gammex-RMI, Madison, WI), and PMMA. Finally, they combined their calculated f(Q) with published overall energy response data to obtain the intrinsic energy dependence of the EBT3 film in water. Results: The calculated f(Q) for EBT and EBT2 films was statistically compatible with previously published data. Between 10 keV and 18 MeV, the variation found in f(Q) of the EBT3 film for water was within 2.3%, with a standard statistical uncertainty less than 1%. If the quantity dose-to-water in the phantom is

  1. Characterization of 2 MeV, 4 MeV, 6 MeV and 18 MeV buildup caps for use with a 0.6 cubic centimeter thimble ionization chamber

    Salyer, R.L.; VanDenburg, J.W.; Prinja, A.K.; Kirby, T.; Busch, R. [Univ. of New Mexico, Albuquerque, NM (United States); Hong-Nian Jow [Sandia National Laboratories, Albuquerque, NM (United States)

    1996-07-01

    The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm{sup 3} thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm{sup 3} active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response.

  2. Characterization of 2 MeV, 4 MeV, 6 MeV and 18 MeV buildup caps for use with a 0.6 cubic centimeter thimble ionization chamber

    The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm3 thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm3 active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response

  3. Performances of large BGO crystals below 20 MeV

    This paper presents the performances of large tapered BGO crystals to low energy photons of 6 to 20 MeV. The read-out of the crystals was made with large area photodiodes associated to shaping amplifiers

  4. Dosimetric comparison of 4 MeV and 6 MeV electron beams for total skin irradiation

    In this study, dosimetric aspects of TSEI consisting of a 4 MeV beam with no spoiler were investigated in comparison to a nominal 6 MeV beam with spoiler, and the potential for clinical applications was evaluated. The TSEI technique is based on the Stanford technique, which utilizes a beam configuration of six-dual fields. MOSFETs were used to measure the optimal gantry angle, profile uniformity, and absolute dose at the calibration point. The depth dose curve of the central axis was measured in the treatment plane using EBT2 film. Photon contamination was measured as the dose at 5 cm depth in a solid water phantom relative to the maximum dose using a parallel plate ion chamber. A MOSFET dosimeter placed on the surface of a humanoid phantom, and EBT2 films inserted into a humanoid phantom were used to verify the TSEI commissioning. Dosimetric aspects of the 4 MeV TSEI beam, such as profile uniformity (±10%) and relative photon contamination (<0.001%), were comparable to those of a 6 MeV TSEI beam. The relative depth dose of the 4 MeV electrons was 81.4% at the surface and 100% at 0.4 cm. For the 6 MeV electrons, the relative depth dose was 93.4% at the surface and 100% from 0.2 cm to 0.4 cm. The calculated B-factor of the 4 MeV TSEI beam was 1.55, and 1.53 for the 6 MeV TSEI. 80% of the prescribed dose was obtained at 0.22 cm depth for the 4 MeV TSEI beam and 0.53 cm for the 6 MeV TSEI beam in the humanoid phantom measurement. The suggested 4 MeV beam for TSEI could be applied to shallow depth skin diseases and to electron boost as second treatment course

  5. Measurement by film dosimetry and calculation of energy dose distributions for electron and photon irradiation of 42 MeV using the Alderson phantom for planning of pendulum irradiation of the mediastinum in the treatment of peripheral bronchial carcinomas

    The energy dose distribution in an Alderson phantom applying a radiation energy of 42 MeV has been determined by film dosimetry and computation; the results have been compared in order to verify both methods and to improve the irradiation of bronchial carcinoma by achieving the best possible protection of healthy tissue and of the spinal cord. The comparative evaluations have shown that there is a good agreement between the calculated results and those measured by film dosimetry. (orig.)

  6. Neutron doses in an 8 MeV linear accelerator and an 18 MeV betatron

    Using uranium fission track dosimeters, dose distributions of neutrons produced by photonuclear reaction in the shielding material were measured near an 8 MeV linear accelerator and an 18 MeV betatron. Dose equivalents, as a function of bremsstrahlung doses in the central beam, are given for different points outside the irradiation field, in particular at the location of the patient. The neutron production was determined as a function of photon energy between 8 and 18 MeV and compared with literature values. (orig./HP)

  7. Recoil proton polarization of neutral pion photoproduction from proton in the energy range between 400 MeV and 1142 MeV

    The recoil proton polarization of the reaction γp → π0p were measured at a C.M. angle of 1000 for incident photon energies between 451 and 1106 MeV, and at an angle of 1300 for energies from 400 MeV to 1142 MeV. One photon decayed from a π0-meson and a recoil proton were detected in coincidence. Two kinds of polarization scatterers were employed. In the range of proton kinetic energy less than 420 MeV and higher than 346 MeV, carbon plates and liquid hydrogen were used for determining the polarization. Results are compared with recent phenomenological analyses. From the Comparison between the present data and the asymmetry data given by the polarized target, the contribution of the invariant amplitudes A3 can be estimated to be small at 1000. (author)

  8. Two body photodisintegration of the deuteron from 100 to 800 MeV

    The total and the differential cross sections for the D(γ,p)n reaction have been measured over the photon energy range 100-800 MeV at the 855 MeV MAMI Microtron in Mainz. The data are presented in the form of thirty-five angular distributions at c.m. proton angles between 30 deg-160 deg in 10 deg intervals and at photon energies in steps of 20 MeV. Previous experimental work is reassessed in the light of the present results and the results compared with some recent theoretical calculations. (author)

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

    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

  10. The low-energy photon tagger NEPTUN

    Savran, D., E-mail: savran@ikp.tu-darmstadt.d [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Schlossgartenstrasse 9, 64289 Darmstadt (Germany); Lindenberg, K.; Glorius, J.; Loeher, B.; Mueller, S.; Pietralla, N.; Schnorrenberger, L.; Simon, V.; Sonnabend, K.; Waelzlein, C. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Schlossgartenstrasse 9, 64289 Darmstadt (Germany); Elvers, M.; Endres, J.; Hasper, J.; Zilges, A. [Institut fuer Kernphysik, Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany)

    2010-02-01

    A new photon tagging spectrometer was built at the superconducting Darmstadt electron linear accelerator (S-DALINAC). The system is designed for tagging photons in an energy range from 6 to 20 MeV with the emphasis on best possible energy resolution and intensity. The absolute energy resolution of photons at 10 MeV is expected to be about 20 keV. With scintillating fibres as focal-plane detectors a maximum rate of tagged photons of 10{sup 4} keV{sup -1}s{sup -1} will be achieved. Detailed design studies including Monte Carlo simulations are presented, as well as results for the measured tagged photon energy profile of the system realized so far. This photon-tagging facility will allow to determine the photon absorption cross-sections as a function of excitation energy and to study the decay patterns of nuclear photo-excitations in great detail.

  11. The low-energy photon tagger NEPTUN

    Savran, D.; Lindenberg, K.; Glorius, J.; Löher, B.; Müller, S.; Pietralla, N.; Schnorrenberger, L.; Simon, V.; Sonnabend, K.; Wälzlein, C.; Elvers, M.; Endres, J.; Hasper, J.; Zilges, A.

    2010-02-01

    A new photon tagging spectrometer was built at the superconducting Darmstadt electron linear accelerator (S-DALINAC). The system is designed for tagging photons in an energy range from 6 to 20 MeV with the emphasis on best possible energy resolution and intensity. The absolute energy resolution of photons at 10 MeV is expected to be about 20 keV. With scintillating fibres as focal-plane detectors a maximum rate of tagged photons of 104 keV -1s -1 will be achieved. Detailed design studies including Monte Carlo simulations are presented, as well as results for the measured tagged photon energy profile of the system realized so far. This photon-tagging facility will allow to determine the photon absorption cross-sections as a function of excitation energy and to study the decay patterns of nuclear photo-excitations in great detail.

  12. Workplace photon radiation fields

    The knowledge of workplace radiation fields is essential for measures in radiation protection. Information about the energy and directional distribution of the incident photon radiation was obtained by several devices developed by the National Radiation Protection Board, United Kingdom, by the Statens Stralskyddsinstitut, Sweden, together with EURADOS and by the Physikalisch-Technische Bundesanstalt, Germany. The devices are described and some results obtained at workplaces in nuclear industry, medicine and science in the photon energy range from 20 keV to 7 MeV are given. (author)

  13. Nuclear Resonance Fluorescence from Uranium above 2 MeV

    Kwan, E.; Howell, C. R.; Raut, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Adekola, A.; Hammond, S. L.; Karwowski, H. J.; Tompkins, J. R.; Huibregtse, C.; Kelley, J. H.; Johnson, B.

    2009-10-01

    The detection of special nuclear materials is critical to the nation's efforts to counter serious threat from nuclear terrorist attacks. A research program has been initiated at TUNL to address the need for new nuclear data on the actinides using the High-Intensity Gamma-Ray Source (HIγS). The high-intensity nearly monoenergic and 100% polarized γ-ray beams from HγS were utilized to search for dipole states in ^235U and ^238U above 2 MeV. This information is necessary for developing technologies using Nuclear-Resonance Fluorescence (NRF) to nonintrusively scan cargo for specific nuclei. The existence of strong nuclear dipole transitions in the actinides above 2 MeV is important for nuclear forensics, because interrogation photons using NRF are the most penetrating at these energies. Results from our experiments at Eγ> 2.0 MeV on uranium will be presented.

  14. PHOTON-PHOTON COLLISIONS

    Burke, D.

    1982-01-01

    Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic eγ scattering. Considerable work has now been accumulated on resonance production by γγ collisions. Preliminary high statistics studies of the photon structure function Fγ2(x,Q2) are given and comments are made on the problems that remain to be solved.

  15. Photon-photon colliders

    Sessler, A.M.

    1995-04-01

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R&D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy.

  16. Photon-photon colliders

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R ampersand D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy

  17. Electret dosemeter response to electrons with energy of 3 Mev, 7 Mev, 11 Mev

    The preliminary results obtained when electret ionization chambers are irradiated with electron of 3, 7, 11 Mev, from 12 mevatron accelerators using a external cop of polyethylene and nylon are presented. (C.G.C.)

  18. Photon-photon collisions

    Highlights of the VIIIth International Workshop on Photon-Photon Collisions are reviewed. New experimental and theoretical results were reported in virtually every area of γγ physics, particularly in exotic resonance production and tests of quantum chromodynamics where asymptotic freedom and factorization theorems provide predictions for both inclusive and exclusive γγ reactions at high momentum transfer. 73 refs., 12 figs

  19. Photon-photon colliders

    Sessler, Andrew M.

    1996-01-01

    Since the seminal work by Ginsburg, et al., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention [1]. A 1990 article by V.I. Telnov describes the situation at that time [2]. In March 1994, the first workshop on this subject was held [3]. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons—the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R&D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy.

  20. A high energy photon polarimeter for astrophysics

    Eingorn, Maxim; Vlahovic, Branislav; Wojtsekhowski, Bogdan; Urciuoli, Guido Maria; De Persio, Fulvio; Meddi, Franco

    2015-01-01

    A high-energy photon polarimeter for astrophysics studies in the energy range from 20 MeV to 1000 MeV is considered. The proposed concept uses a stack of silicon micro-strip detectors where they play the roles of both a converter and a tracker. The purpose of this paper is to outline the parameters of such a polarimeter and to estimate the productivity of measurements. Our study supported by a Monte Carlo simulation shows that with a one-year observation period the polarimeter will provide 5.5 % accuracy of the polarization degree for a photon energy of 100 MeV, which would be a significant advance relative to the currently explored energy range of a few MeV. The proposed polarimeter design could easily be adjusted to the specific photon energy range to maximize efficiency if needed.

  1. Combined photon-neutron radiography for nondestructive analysis of materials

    Combined photon-neutron radiography was investigated as a nondestructive method to determine the shape and material composition of complex objects. A system consisting of photon and neutron sources in a cone beam configuration and a 2D detector array was modeled using the MCNP5 code. Photon-to-neutron transmission ratios were determined for a car engine using 0.1, 0.5, 2.5 MeV neutrons and 0.2, 0.5, 1 MeV photons. Focusing on inherent difference between neutron and photon interactions with matter, it was possible to classify materials within the scanned object. (author)

  2. 50 MeV polarimeter

    A description is given of the construction, operation and calibration of the 50 MeV polarimeter which was used at the ZGS. The dependence of the observed counts on various parameters, including the beam polarization, beam intensity and the solid angle in the two polarimeter arms is also discussed

  3. Photon-photon collisions

    The current status, both theoretical and experimental, of two photon collision physics is reviewed with special emphasis on recent experimental results from e+e- storage rings. After a complete presentation of the helicity amplitude formalism for the general process e+e- → Xe+e-, various approximations (transverse photon, Weisaecker Williams) are discussed. Beam polarisation effects and radiative corrections are also briefly considered. A number of specific processes, for which experimental results are now available, are then described. In each case existing theoretical prediction are confronted with experimental results. The processes described include single resonance production, lepton and hadron pair production, the structure functions of the photon, the production of high Psub(T) jets and the total photon photon cross section. In the last part of the review the current status of the subject is summarised and some comments are made on future prospects. These include both extrapolations of current research to higher energy machines (LEP, HERA) as well as a brief mention of both the technical realisation and the physics interest of the real γγ and eγ collisions which may be possible using linear electron colliders in the 1 TeV energy range

  4. Photon-photon collisions

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  5. The MAX-lab tagged photon facility

    The tagged photon facility at MAX-lab in Lund, Sweden has recently been upgraded to higher energy. The present facility consists of a ∝200 MeV linac followed by a pulse stretcher ring. The extracted electron beam (∝50% duty factor) is used to generate a bremsstrahlung beam and photons are tagged by a choice of two different tagging spectrometers, optimized for different energy regions. The tagged photon range may presently be chosen between 15 MeV and 185 MeV. The energy resolution is typically ∝0.5 MeV and the tagged intensity is ∝106 MeV-1s-1. The available energy may increase somewhat in the near future. The initial experimental programme includes Compton scattering on deuterium using very large NaI detectors, (γ,π+) measurements using both solid-state and scintillator set-ups, and tests of electromagnetic calorimeter elements for the PANDA detector. Initial tests have been performed on total absorption cross-section measurements on 4He, using an active target, and on 6,7Li. A linearly polarized photon beam from coherent bremsstrahlung is being commissioned. The MAX-lab tagged photon facility is presented and an overview of the present experimental programme given.

  6. Transport calculations for a 14.8 MeV neutron beam in a water phantom

    A coupled neutron/photon Monte Carlo radiation transport code (MORSE-CG) has been used to calculate neutron and photon doses in a water phantom irradiated by 14.8 MeV neutrons from the Gas Target Neutron Source. The source-collimator-phantom geometry was carefully simulated. Results of calculations utilizing two different statistical estimators (next-collision and track-length) are presented

  7. Decay of photon with high as well as low energy

    Bhattacharyya, Indranath

    2016-01-01

    The decay of photon by the influence of magnetic field is considered. It is shown here that if the photon energy is grater than 1 MeV then photon can decay electron positron pair, but if it remains below 1 MeV then photon decays into neutrino antineutrino pair. The decay rates for both of the processes are calculated. All possible Feynman diagrams are taken into account to construct the matrix element for either of the processes. In the second process all three type of neutrinos are considered. The significance of these processes are discussed briefly.

  8. Focusing the photon dose in a head phantom

    The 30 keV photons stereotactic focusing is being examined for two kinds of collimated sources and it has been found less advantageous as compared to the gamma-knife MeV range. (author) 2 figs., 2 refs

  9. Polarization observables in deuteron photodisintegration below 360 MeV

    Glister, Jacqueline; Lee, Byungwuek; Gilman, R; Sarty, Adam; Strauch, Steffen; Higinbotham, Douglas; Piasetzky, Eliazer; Allada, Kalyan; Armstrong, Whitney; Arrington, John; Beck, Arie; Benmokhtar, Fatiha; Berman, Barry; Boeglin, Werner; Brash, Edward; Camsonne, Alexandre; Calarco, John; Chen, Jian-Ping; Choi, Seonho; Chudakov, Eugene; Coman, Luminita; Craver, Brandon; Cusanno, Francesco; Dumas, Jonathan; Dutta, Chiranjib; Feuerbach, Robert; Freyberger, Arne; Frullani, Salvatore; Garibaldi, Franco; Hansen, Jens-Ole; Holmstrom, Timothy; Hyde, Charles; Ibrahim, Hassan; Ilieva, Yordanka; De Jager, Cornelis; Jiang, Xiaodong; Jones, Mark; Kang, Hoyoung; Kelleher, Aidan; Khrosinkova, Elena; Kuchina, Elena; Kumbartzki, Gerfried; LeRose, John; Lindgren, Richard; Markowitz, Pete; Beck, S. May-Tal; McCullough, Emily; Meekins, David; Meziane, Mehdi; Meziane, Zein-Eddine; Michaels, Robert; Moffit, Bryan; Norum, Blaine; Oh, Yongseok; Olson, Michael; Paolone, Michael; Paschke, Kent; Perdrisat, Charles; Potokar, Milan; Pomatsalyuk, Roman; Pomerantz, Ishay; Puckett, Andrew; Punjabi, Vina; Qian, Xin; Qiang, Yi; Ransome, Ronald; Reyhand, Meral; Roche, Julie; Rousseau, Yannick; Saha, Arunava; Sawatzky, Bradley; Schulte, Elaine; Hashemi Shabestari, Mitra; Shahinyan, Albert; Shneor, R; Sirca, Simon; Slifer, Karl; Solvignon, Patricia; Song, JeongSeog; Sparks, Rachel; Subedi, Ramesh; Urciuoli, Guido; Wang, Kebin; Wojtsekhowski, Bogdan; Yan, Xinhu; Yao, Huan; Zhan, Xiaohui

    2011-03-01

    High precision measurements of induced and transferred recoil proton polarization in d(polarized gamma, polarized p})n have been performed for photon energies of 277--357 MeV and theta_cm = 20 degrees -- 120 degrees. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. At the low energies of this experiment, theory continues to fail to reproduce the data, indicating that either something is missing in the calculations and/or there is a problem with the accuracy of the nucleon-nucleon potential being used.

  10. Polarization Observables in Deuteron Photodisintegration below 360 MeV

    Glister, J; Lee, B W; Gilman, R; Sarty, A J; Strauch, S; Higinbotham, D W; Piasetzky, E; Allada, K; Armstrong, W; Arrington, J; Beck, A; Benmokhtar, F; Berman, B L; Boeglin, W; Brash, E; Camsonne, A; Calarco, J; Chen, J P; Choi, Seonho; Chudakov, E; Coman, L; Craver, B; Cusanno, F; Dumas, J; Dutta, C; Feuerbach, R; Freyberger, A; Frullani, S; Garibaldi, F; Hansen, J -0; Holmstrom, T; Hyde, C E; Ibrahim, H; Ilieva, Y; de Jager, C W; Jiang, X; Jones, M K; Kang, H; Kelleher, A; Khrosinkova, E; Kuchina, E; Kumbartzki, G; LeRose, J J; Lindgren, R; Markowitz, P; Beck, S May-Tal; McCullough, E; Meekins, D; Meziane, M; Meziani, Z -E; Michaels, R; Moffit, B; Norum, B E; Oh, Y; Olson, M; Paolone, M; Paschke, K; Perdrisat, C F; Potokar, M; Pomatsalyuk, R; Pomerantz, I; Puckett, A; Punjabi, V; Qian, X; Qiang, Y; Ransome, R; Reyhan, M; Roche, J; Rousseau, Y; Saha, A; Sawatzky, B; Schulte, E; Shabestari, M; Shahinyan, A; Shneor, R; Sirca, S; Slifer, K; Solvignon, P; Song, J; Sparks, R; Subedi, R; Urciuoli, G M; Wang, K; Wojtsekhowski, B; Yan, X; Yao, H; Zhan, X; Zhu, X

    2010-01-01

    High precision measurements of induced and transferred recoil proton polarization in d(polarized gamma, polarized p})n have been performed for photon energies of 277--357 MeV and theta_cm = 20 degrees -- 120 degrees. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. At the low energies of this experiment, theory continues to fail to reproduce the data, indicating that either something is missing in the calculations and/or there is a problem with the accuracy of the nucleon-nucleon potential being used.

  11. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  12. Nuclear photon science with inverse compton photon beam

    Recent developments of the synchrotron radiation facilities and intense lasers are now guiding us to a new research frontier with probes of a high energy GeV photon beam and an intense and short pulse MeV γ-ray beam. New directions of the science developments with photo-nuclear reactions are discussed. The inverse Compton γ-ray has two good advantages for searching for a microscopic quantum world; they are 1) good emittance and 2) high linear and circular polarizations. With these advantages, photon beams in the energy range from MeV to GeV are used for studying hadron structure, nuclear structure, astrophysics, materials science, as well as for applying medical science. (author)

  13. Proton-proton bremsstrahlung at 280 MeV

    A proton-proton bremsstrahlung experiment has been carried out at TRIUMF using a 280-MeV polarized proton beam impinging on a liquid-hydrogen target. All three outgoing particles were detected: the higher-energy proton in a magnetic spectrometer, the lower-energy proton with plastic scintillators, and the photon in lead-glass Cherenkov detectors. The experiment shows the first unambiguous evidence for off-shell effects in the free nucleon-nucleon interaction, in that the analyzing powers disagree strongly with the predictions of the soft-photon approximation (which incorporates only on-shell information) but are consistent with the results of calculations using the Bonn and Paris potentials

  14. Radiography studies with gamma rays produced by 14-MeV fusion neutrons

    Oxygen contained in pure water has been activated via the 16O(n, p)16N reaction using 14-MeV neutrons produced at a neutron generator with the 3H(d,n)4He source. Photons of 6.129 and 7.115 MeV, generated by the decay of 7.13-second 16N, were then used to demonstrate the feasibility of employing highly penetrating, nearly monoenergetic gamma rays for radiography studies of thick, dense objects composed of elements with medium to relatively high atomic numbers. A simple radiography apparatus was constructed by circulating water continuously between a position near the target of the neutron generator and a remote location where photon transmission measurements were conducted. A sodium iodide scintillator was employed to detect the photons. Pulses equivalent to photon energies smaller than 2.506 MeV (corresponding to the cascade sum of 1.333- and 1.173-MeV gamma rays from the decay of 5.271-year 60Co) were rejected by the electronics settings in order to reduce background and improve the signal-to-noise (S/N) ratio. Respectable S/N ratios on the order of 20-to-1 were achieved with this setup. Most of the background (N) could be attributed to ambient environmental radiation and cosmic-ray interactions with the lead shielding and detector. Four representative objects were examined by photon radiography in this study. This demonstrated how such - interesting features as hidden holes and discontinuities in atomic number could be easily identified from observed variations in the intensity of transmitted photons. Some advantages of this technique are described, and potential applications are suggested for a future scenario where fusion reactors are used to generate electric power and very intense sources of high-energy photons from 16N decay are continuously available as a byproduct of the reactor cooling process

  15. Activation analysis using γ photons

    This report summarizes all the data required for using photonuclear reactions in the field of analysis. After a brief review of the elementary properties of nuclear reactions induced by photon irradiation, the main characteristics are given of high energy (E > 20 MeV) Bremsstrahlung sources. The principle of activation analysis based on the use of photons is given. Actual examples of the analytic possibilities are described in detail, in particular in the case of the determination of very small quantities (-6) of C, N, O and F. The influence of interfering nuclear reactions is discussed. (author)

  16. Microwave Photonics

    A J Seeds; Liu, C. P.; Ismail, T; Fice, M. J.; Pozzi, F.; Steed, R. J.; Rouvalis, E.; Renaud, C.C.

    2010-01-01

    Microwave photonics is the use of photonic techniques for the generation, transmission, processing and reception of signals having spectral components at microwave frequencies. This tutorial reviews the technologies used and gives applications examples.

  17. Polychromatic photons

    Keller, Ole

    2002-01-01

    A review is given of the space-time wave mechanics of single photons, a subject with an almost century long history. The Landau-Peierls photon wave function, which is related nonlocally to the electromagnetic field is first described, and thereafter the so-called energy wave function, based on the...... positive-frequency Riemann-Silberstein vectors, is discussed. Recent attempts to understand the birth process of a photon emerging from a single atom are summarized. The polychromatic photon concept is introduced, and it is indicated how the wave mechanics of polychromatic photons can be upgraded to wave...... train quantum electrodynamics. A brief description of particle (photon) position operators is given, and it is shown that photons usually are only algebraically confined in an emission process. Finally, it is demonstrated that the profile of the birth domain of a radio-frequency photon emitted in a...

  18. Induced photonuclear interaction by Rhodotron-TT200 10 MeV electron beam

    Farshid Tabbakh; Mojtaba Mostajab Aldaavati; Mahdieh Hoseyni; Khadijeh Rezaee Ebrahim Saraee

    2012-02-01

    In this paper the photonuclear interaction induced by 10 MeV electron beam generating high-intensity neutrons is studied. Since the results depend on the target material, the calculations are performed for Pb, Ta and W targets which have high , in a simple geometry. MCNPX code has been used to simulate the whole process. Also, the results of photon generation has been compared with the experimental results to evaluate the reliability of the calculation. The results show that the obtained neutron flux can reach up to 1012 n/cm2 /s with average energies of 0.9 MeV, 0.4 MeV and 0.9 MeV for these three elements respectively with the maximum heat deposited as 3000 W/c3,4500 W/c3 and 6000 W/c3.

  19. Photon Structure

    Grindhammer, Guenter

    2001-01-01

    Large pT processes at HERA, initiated by almost real and by virtual photons, provide information on the structure of the photon. We report on the latest measurements of dijets and large pT particle production with the H1 detector. This includes a leading order determination of an effective virtual photon parton density, of the gluon density of the photon, and comparisons with models.

  20. Nuclear photonics

    Habs, D.; Guenther, M. M.; Jentschel, M.; Thirolf, P. G. [Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Max Planck Institut fuer Quantenoptik, D-85748 Garching (Germany); Institut Laue-Langevin, F-38042 Grenoble (Germany); Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany)

    2012-07-09

    With the planned new {gamma}-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 10{sup 13}{gamma}/s and a band width of {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -3}, a new era of {gamma} beams with energies up to 20MeV comes into operation, compared to the present world-leading HI{gamma}S facility at Duke University (USA) with 10{sup 8}{gamma}/s and {Delta}E{gamma}/E{gamma} Almost-Equal-To 3 Dot-Operator 10{sup -2}. In the long run even a seeded quantum FEL for {gamma} beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused {gamma} beams. Here we describe a new experiment at the {gamma} beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for {gamma} beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for {gamma} beams are being developed. Thus, we have to optimize the total system: the {gamma}-beam facility, the {gamma}-beam optics and {gamma} detectors. We can trade {gamma} intensity for band width, going down to {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -6} and address individual nuclear levels. The term 'nuclear photonics' stresses the importance of nuclear applications. We can address with {gamma}-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, {gamma} beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to {mu}m resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of

  1. Inclusive Dark Photon Search at LHCb

    Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei

    2016-01-01

    We propose an inclusive search for dark photons $A'$ at the LHCb experiment based on both prompt and displaced di-muon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon $A' \\to \\mu^+ \\mu^-$ rate can be directly inferred from the off-shell photon $\\gamma^* \\to \\mu^+ \\mu^-$ rate, making this a fully data-driven search. For Run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.

  2. Elastic and nuclear Raman scattering of photons

    Some recent experimental studies of fundamental photon scattering processes and inelastic scattering performed at the Negev IRR-2 reactor in the E 166Er and 238U in the approx. 15 MeV region, performed at the University of Illinois are discussed. (orig.) 891 KBE/orig. 892 ARA

  3. Searches for dark photons at the Mainz Microtron

    Merkel, H.; Achenbach, P.; Gayoso, C. Ayerbe; Beranek, T.; Bernauer, J. C.; Böhm, R.; Correa, L.; Denig, A.; Distler, M. O.; Esser, A.; Gómez, M.; Kegel, S.; Kohl, Y.; Mihovilovič, M.; Middleton, D. G.; Müller, U.; Nungesser, L.; Pochodzalla, J.; Rohrbeck, M.; Majos, S. Sánchez [Institut für Kernphysik, Johannes Gutenberg-Universität, D-55099 Mainz (Germany); and others

    2013-11-07

    The A1 Collaboration at the Mainz Microtron (MAMI) operates high resolution spectrometers at very high luminosities for fixed target electron scattering experiments. The setup is well suited for the search for dark photons in the mass range between 50 MeV and 300 MeV. In these experiments, a possible dark photon would appear as a sharp peak in the mass spectrum of di-lepton electro-production. In this presentation the potential of the setup is presented and the possibilities for future experiments for dark photon searches at MAMI are discussed.

  4. Photonic Lantern

    Leon-Saval, Sergio; Bland-Hawthorn, Joss

    2015-01-01

    Photonic lanterns allow for a low-loss transformation of a multimode waveguide into a discrete number of single-mode waveguides and vice versa, thus, enabling the use of single-mode photonic technologies in multimode systems. In this review, we will discuss the theory and function of the photonic lantern, along with several different variants of the technology. We will also discuss some of its applications in more detail.

  5. Emission patterns of neutral pions in 40A MeV Ta+Au reactions

    Differential cross sections of neutral pions emitted in 181Ta+197Au collisions at a beam energy of 39.5A MeV have been measured with the two-arm photon spectrometer (TAPS). The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the thermal model, nor when the reabsorption of pions is accounted for in a phenomenological model. However, high energy and high momentum tails of the pion spectra can be well fitted through thermal distributions with unexpectedly soft temperature parameters below 10 MeV.

  6. Observation of an eta'/sub c/ candidate state with mass 3592 +- 5 MeV

    An eta'/sub c/ candidate state is observed at a mass M = 3592 +- 5 MeV and with a natural linewidth GAMMA<8 MeV (95% confidence level), by using the ''crystal ball'' NaI(Tl) detector at the Stanford Linear Accelerator Center (SPEAR). The evidence is found in the inclusive photon spectrum in decays of the psi'(3684), where a signal is observed corresponding to a radiative transition to this state with branching ratio between 0.2% and 1.3%

  7. Photon energy absorption parameters for some polymers

    Singh, Tejbir; Rajni [Physics Department, M.M. University, Mullana-133 203 Haryana (India); Kaur, Updesh [Physics Department, P.K.R.J.S.S. School, Ambala City, Haryana (India); Singh, Parjit S., E-mail: dr_parjit@hotmail.co [Physics Department, Punjabi University, Patiala-147 002 Punjab (India)

    2010-03-15

    Some photon energy absorption parameters viz. mass energy absorption coefficient (mu/rho){sub en}, photon energy absorption effective atomic number (Z{sub PEA}), electron density (N{sub e}) and KERMA relative to air has been computed in the energy range from 1 keV to 20 MeV for some polymers such as nylon, poly-acrylo-nitrile, poly-methyl-acrylate, poly-vinyl-chloride, poly-styrene, synthetic rubber and poly-tetra-fluro-ethylene. The dependence of different parameters on incident photon energy and chemical composition of the selected polymers has been studied .

  8. High energy photons production in nuclear reactions

    Hard photon production, in nucleus-nucleus collisions, were studied at beam energies between 10 and 125 MeV. The main characteristics of the photon emission are deduced. They suggest that the neutron-proton collisions in the early stage of the reaction are the main source of high energy gamma-rays. An overview of the theoretical approaches is given and compared with experimental results. Theoretical attempts to include the contribution of charged pion exchange currents to photon production, in calculations of proton-nucleus-gamma and nucleus-nucleus-gamma reactions, showed suitable fitting with experimental data

  9. Microwave photonics

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  10. Photonic glasses

    Gan, Fuxi

    2006-01-01

    This book introduces the fundamental mechanism of photonic glasses - the linear and nonlinear optical effects in glass under intense light irradiation: phot-induced absorption, refraction, polarization, frequency, coherence and monochromaticity changes. Emphasis is placed on new developments in the structure, spectroscopy and physics of new glassy materials for photonics applications, such as optical communication, optical data storage, new lasers and new photonic components and devices. The book presents the research results of the authors in new glasses for photonics over the last decade. Sa

  11. Hidden Photons in Aharonov-Bohm-Type Experiments

    Arias, Paola; Diaz, Marco Aurelio; Jaeckel, Joerg; Koch, Benjamin; Redondo, Javier

    2016-01-01

    We discuss the Aharonov-Bohm effect in the presence of hidden photons kinetically mixed with the ordinary electromagnetic photons. The hidden photon field causes a slight phase shift in the observable interference pattern. It is then shown how the limited sensitivity of this experiment can be largely improved. The key observation is that the hidden photon field causes a leakage of the ordinary magnetic field into the supposedly field-free region. The direct measurement of this magnetic field can provide a sensitive experiment with a good discovery potential, particularly below the $\\sim$ meV mass range for hidden photons.

  12. Detector for high-energy photon backscatter

    Silver, Michael D.; Erker, Joseph W.; Duncan, Michael Z.; Hartford, Thomas J.; Sivers, E. A.; Hopkinson, James F.

    1993-12-01

    High energy photon backscatter uses pair production to probe deep beneath surfaces with single side accessibility or to image thick, radiographically opaque objects. At the higher photon energies needed to penetrate thick and/or highly attenuating objects, Compton backscatter becomes strongly forward peaked with relatively little backscatter flux. Furthermore, the downward energy shift of the backscattered photon makes it more susceptible to attenuation on its outbound path. Above 1.022 MeV, pair production is possible; at about 10 MeV, pari production crosses over Compton scatter as the dominant x-ray interaction mechanism. The backscattered photons can be hard x rays from the bremsstrahlung of the electrons and positrons or 0.511 MeV photons from the annihilation of the positron. Monte Carlo computer simulations of such a backscatter system were done to characterize the output signals and to optimize a high energy detector design. This paper touches on the physics of high energy backscatter imaging and describes at some length the detector design for tomographic and radiographic imaging.

  13. Processes related to photon-photon collisions

    Two types of processes, related to photon-photon collisions, are considered: deep inelastic Compton scattering, and photon pair production. The relevant theoretical and experimental literature is reviewed

  14. Unparticle effects in photon-photon scattering

    Chang, Chun-Fu; Cheung, Kingman; Yuan, Tzu-Chiang

    2008-01-01

    Elastic photon-photon scattering can only occur via loop diagrams in the standard model and is naturally suppressed. Unparticle can induce tree-level photon-photon scattering through the operator F_{\\mu\

  15. Praseodymium activation detector for measuring bursts of 14 MeV neutrons

    A new, accurate, neutron activation detection scheme for measuring pulsed neutrons has been designed and tested. The detection system is sensitive to neutrons with energies above 10 MeV; importantly, it is insensitive to gamma radiation 141Pr, an element that has a single, naturally occurring isotope, a significant n,2n cross-section, and decays by positron emission that result in two coincident 511 keV photons. Neutron fluences are thus inferred by relating measured reaction product decay activity to fluence. Specific sample activity is measured using the sum-peak method to count gamma-ray coincidences from the annihilation of the positron decay products. The system was tested using 14 and 2.45 MeV neutron bursts produced by NSTec Dense Plasma Focus Laboratory fusion sources. Lead, copper, beryllium, and silver activation detectors were compared. The detection method allows measurement of 14 MeV neutron yield with a total error of ∼18%.

  16. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    NONE

    1997-03-01

    For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

  17. Comment on "Material Evidence of a 38 MeV Boson"

    Bernhard, J; Schlüter, T; Schönning, K

    2012-01-01

    In the recent preprint 1202.1739 it was claimed that preliminary data presented by COMPASS at recent conferences confirm the existence of a resonant state of mass 38 MeV decaying to two photons. This claim was made based on structures observed in two-photon mass distributions which however were shown only to demonstrate the purity and mass resolution of the $\\pi^0$ and $\\eta$ signals. The additional structures are understood as remnants of secondary interactions inside the COMPASS spectrometer. Therefore, the COMPASS data do not confirm the existence of this state.

  18. n-p-γ Bremsstrahlung below 210 MeV bombarding energy

    The experimental knowledge of the neutron-proton-gamma below 210 MeV bombarding energy is discussed. The knowledge of this process is poor and due to the small intensity and bad resolution of the neutron beams. In this energy region the one-pion exchange is the main source of high energy photons. The different models proposed to explain the process are summarized. As at higher bombarding energies heavier mesons are also expected to couple with the photons, the investigation of the elementary process above the pion threshold is suggested

  19. Polarization sensitivity of a segmented HPGe detector up to 10 MeV

    Hutter, C; Bayer, W; Galaviz, D; Hartmann, T; Mohr, P J; Müller, S; Rochow, W; Savran, D; Sonnabend, K; Vogt, K; Volz, S; Zilges, A

    2002-01-01

    Linear gamma-ray polarization can be measured using segmented germanium detectors. The polarization sensitivity of the Compton scattering process leads to asymmetries in the signals of a segmented detector. We have measured the polarization sensitivity of a four-fold segmented large volume germanium detector up to photon energies of approximately 10 MeV for the first time. The detector and its performance are compared to smaller Compton polarimeters which have been analyzed in previous work. A possible application of the described Compton polarimeter will be parity assignments in photon scattering experiments.

  20. The effect of 14.7 MeV neutrons on MOS structures

    Six MOS transistors on a common chip were irradiated with 14.7 MeV neutrons; the accompanying gamma radiation contributed 4% to the neutron dose. The mean energy of these photons was about 1 MeV. The dependence of the threshold voltage shift on the dose equivalent was investigated for several gate bias voltages. The MOS transistors irradiated with neutrons to a total dose equivalent of 188.40 Sv were also annealed isochronously in steps of 20 degC. The annealing curves are shown and activation energies of traps calculated therefrom. It was also found that the fading curve of fast-neutron-irradiated MOS transistors differed from that of photon irradiated ones. (J.B.)

  1. Delbrueck scattering of monoenergetic photons

    The Delbrueck effect was experimentally investigated in high Z nuclei with monoenergetic photons in the range 6.8-11.4 MeV. Two different methods were used for measurements of the differential scattering cross-section, in the 25-140 deg range and in the forward direction (theta = 1.5 deg), respectively. The known Compton scattering cross-section was used in a new and unique way for the determination of the elastic scattering cross-section. Isolation of the contribution of the real Delbrueck amplitudes to the cross-section was crried out successfully. Experimental confirmation of the theoretical calculations of Papatzacos and Mork and measurement, for the first time, of the Rayleigh scattering in the 10 MeV region are also reported. One of the most interesting findings is the presence of Coulomb corrections in Delbrueck scattering at these energies. More theoretical effort is needed in this last direction. (author)

  2. Photon Stars

    Schmidt, H. -J.; Homann, F.

    1999-01-01

    We discuss numerical solutions of Einstein's field equation describing static, spherically symmetric conglomerations of a photon gas. These equations imply a back reaction of the metric on the energy density of the photon gas according to Tolman's equation. The 3-fold of solutions corresponds to a class of physically different solutions which is parameterized by only two quantities, e.g. mass and surface temperature. The energy density is typically concentrated on a shell because the center c...

  3. Microwave photonics

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  4. Photonic Nanojets

    Heifetz, Alexander; Kong, Soon-Cheol; Alan V. Sahakian; Taflove, Allen; Backman, Vadim

    2009-01-01

    This paper reviews the substantial body of literature emerging since 2004 concerning photonic nanojets. The photonic nanojet is a narrow, high-intensity, non-evanescent light beam that can propagate over a distance longer than the wavelength λ after emerging from the shadow-side surface of an illuminated lossless dielectric microcylinder or microsphere of diameter larger than λ. The nanojet’s minimum beamwidth can be smaller than the classical diffraction limit, in fact as small as ~λ/3 for m...

  5. A high energy photon polarimeter for astrophysics

    Eingorn, Maxim; Fernando, Lakma; Vlahovic, Branislav; Ilie, Cosmin; Wojtsekhowski, Bogdan; Urciuoli, Guido Maria; De Persio, Fulvio; Meddi, Franco

    2015-01-01

    A high-energy photon polarimeter for astrophysics studies in the energy range from 20 MeV to 1000 MeV is considered. The proposed concept uses a stack of silicon micro-strip detectors where they play the roles of both a converter and a tracker. The purpose of this paper is to outline the parameters of such a polarimeter and to estimate the productivity of measurements. Our study supported by a Monte Carlo simulation shows that with a one-year observation period the polarimeter will provide 6%...

  6. Monte Carlo simulation of microbeam photon irradiation of a single cell

    The numerical model presented in this paper offers the possibility of analyzing cell compartment response to irradiation microbeam fields of photons of different energies, beam sizes and cells arrangements. The results of the stochastic aspects of energy dissipation by photons interacting with the cells show that the energy deposited in the surrounding cells is 21% of the energy deposited in the target cell. The simulations with different photon beam energies ranging from 0.01 MeV to 2 MeV show that increased photon beam energy does not change the ratio of energy deposited in surrounding cell to that in target cell. (author)

  7. The ENDF/B-VI photon interaction library

    The ENDF/B-VI photon interaction library includes data to describe the interaction of photons with the elements Z = 1 to 100 over the energy range 10 eV to 100 MeV. This library has been designed to meet the traditional needs of users to model the interaction and transport of primary photons. However, this library contains additional information which used in a combination with our other data libraries can be used to perform much more detailed calculations, e.g., emission of secondary fluorescence photons. This paper describes both traditional and more detailed uses of this library

  8. Testing helicity-dependent γγ → γγ scattering in the region of MeV

    Light-by-light scatterings contain rich information on photon coupling to virtual and real particle states. In the context of quantum electrodynamics (QED), photons can couple to a virtual e+e− pair. Photons may also couple to known resonance states in the context of quantum chromodyanmics and electroweak dynamics in higher energy domains and possibly couple to unknown resonance states beyond the standard model. The perturbative QED calculations manifestly predict a maximized cross section at the MeV scale; however, no example of exact real-photon–real-photon scattering has yet been observed. Hence, we propose direct measurement with the maximized cross section at the center-of-mass system energy of 1–2 MeV to establish a firm footing at the MeV scale. Given current state of the art high power lasers, helicity-dependent elastic scattering may be observed at a reasonable rate, if a photon–photon collider exploiting γ-rays generated by the inverse nonlinear Compton process with electrons delivered from laser-plasma accelerators (LPA) are properly designed. We show that such verification is feasible in a table-top scale collider, which may be an unprecedented breakthrough in particle accelerators for basic physics research in contrast to energy frontier colliders

  9. Polarimeter for high energy photons

    Wojtsekhowski, Bogdan; Vlahovic, Branislav; Tedeschi, David; Danagulian, Samuel; Litvienko, Vladimir; Pinayev, Igor

    1999-11-01

    The physics program at TJNAF includes fundamental experiments with polarized photon beam in few GeV energy range. Development of the Polarimeter for use in Hall B experiments is the subject of present abstract. We have proposed to take advantage of the recent progress in silicon micro strip detectors for measurement of the geometry and angle correlation in electron positron pair production from an amorphous converter. A detailed analysis of the setup including MC simulation shows an experimental asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of the photon energies. This asymmetry value is confirmed by our experimental results obtained using 100 percent polarized 40 MeV γ rays at Duke FEL.

  10. Testing QCD in Photon-Photon Interactions

    Soldner-Rembold, Stefan

    1998-01-01

    At high energies photon-photon interactions are dominated by quantum fluctuations of the photons into fermion-antifermion pairs and into vector mesons. This is called photon structure. Electron-positron collisions at LEP are an ideal laboratory for studying photon structure and for testing QCD.

  11. Vesicle Photonics

    Vasdekis, Andreas E.; Scott, E. A.; Roke, Sylvie; Hubbell, J. A.; Psaltis, D.

    2013-04-03

    Thin membranes, under appropriate boundary conditions, can self-assemble into vesicles, nanoscale bubbles that encapsulate and hence protect or transport molecular payloads. In this paper, we review the types and applications of light fields interacting with vesicles. By encapsulating light-emitting molecules (e.g. dyes, fluorescent proteins, or quantum dots), vesicles can act as particles and imaging agents. Vesicle imaging can take place also under second harmonic generation from vesicle membrane, as well as employing mass spectrometry. Light fields can also be employed to transport vesicles using optical tweezers (photon momentum) or directly pertrurbe the stability of vesicles and hence trigger the delivery of the encapsulated payload (photon energy).

  12. Photonic crystals

    Busch, Kurt; Wehrspohn, Ralf B; Föll, Helmut

    2006-01-01

    The majority of the contributions in this topically edited book stems from the priority program SPP 1113 ""Photonische Kristalle"" run by the Deutsche Forschungsgemeinschaft (DFG), resulting in a survey of the current state of photonic crystal research in Germany. The first part of the book describes methods for the theoretical analysis of their optical properties as well as the results. The main part is dedicated to the fabrication, characterization and modeling of two- and three-dimensional photonic crystals, while the final section presents a wide spectrum of applications: gas sensors, micr

  13. Dosimetry in high-energy photon fields for the calibration of measuring instruments for radiation protection purposes

    This report describes the dosimetry in various reference photon fields with energies between 4.4 MeV and about 8 MeV. Two dosimetric quantities were chosen. The air kerma was determined from measurements without a phantom and the absorbed dose to water from measurements with a phantom. This mean that the range of realization of the quantity air kerma has been extended from the energy of Co-60 photons to about 8 MeV. The results can serve as basis for the calibration of radiation protection dosemeters in nuclear power plants (0-16(n,p)N-16 reaction) with high energy photons. (orig./HP)

  14. Experimental investigation of quadrupole virtual photon spectrum

    To test experimentally the quadrupole virtual photon spectrum calculation, the (e,α) excitation function of an isolated 2+ level at 20.14 MeV in 24Mg was measured. The most recent calculations in DWBA, including nuclear size effects, are compared to this experimental curve. The differential cross section d2σ/dΩdE was measured 480, 900, 1320 in the laboratory system, for total electron energies of 20.0, 20.8, 21.5, 24.0, 26.0, 28.0, 30.0, 32.0, 36.0, and 40.0 MeV. The reduced matrix element B(E2) of the 20,14 MeV level is extracted as a secondary product of this work. (author)

  15. Search for photon oscillations into massive particles

    Fouché, Mathilde; Faure, Stéphane; Rizzo, Carlo; Mauchain, Julien; Nardone, Marc; Battesti, Remy; Martin, Luc; Sautivet, Anne-Marie; Paillard, Jean-Luc; Amiranoff, François

    2008-01-01

    In this paper, we present the final results of our experiment on photon-axion oscillations in the presence of a magnetic field, which took place at LULI (Laboratoire pour l'Utilisation des Lasers Intenses, Palaiseau, France). Our null measurement allowed us to exclude the existence of axions with inverse coupling constant $M>9.\\times 10^5$ GeV for low axion masses and to improve the preceding BFRT limits by a factor 3 or more for axion masses $1.1 {meV} meV}$. We also show that our experimental results improve the existing limits on the parameters of a low mass hidden-sector boson usually dubbed "paraphoton" because of its similarity with the usual photon.

  16. Photonic crystals principles and applications

    Gong, Qihuang

    2013-01-01

    IntroductionPrimary Properties of Photonic CrystalsFabrication of Photonic CrystalsPhotonic Crystal All-Optical SwitchingTunable Photonic Crystal FilterPhotonic Crystal LaserPhotonic Crystal Logic DevicesPhotonic Crystal Sensors

  17. Photon Structure in Photon Proton Interactions

    Vossebeld, J. H.

    1998-01-01

    Photoproduction of jets at HERA provides information on the partonic structure of the photon. We report on the latest dijet photoproduction results, for real photons and for photons at low virtualities, measured with the ZEUS detector.

  18. Photon Differentials

    Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny;

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation of...

  19. Photon differentials

    Schjøth, Lars; Revall Frisvad, Jeppe; Erleben, Kenny;

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation of...

  20. Two-Photon Processes and Photon Structure

    Schienbein, I.

    2002-01-01

    In this article aspects of photon-photon physics related to the structure of real and virtual photons are reviewed. A re-calculation of the virtual photon-photon box is performed and some discrepancies in the literature are clarified. A useful compilation of various relevant limits derived from the most general expressions is provided. Furthermore, structure functions of spin-averaged, transverse and longitudinal virtual target photons are defined and discussed. Finally, the factorization of ...

  1. <600> MeV synchro-cyclotron

    1971-01-01

    One of the 14 pancakes of the new magnet coils for the 600 MeV synchro-cyclotron which were wound and coated with epoxy resin on the CERN site. These new coils will replace the present ones which have been in use for more than 14 years but are now showing signs of deteriorations.

  2. MeV fullerene impacts on mica

    Doebeli, M.; Scandella, L. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ames, F. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Hillock heights on mica irradiated with MeV C{sub 60} ions have been investigated systematically. Results show that the small range of secondary particles along the track plays a crucial role in defect production. (author) figs., tab., refs.

  3. Neutron and photon spectra in LINACs

    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 10–6 and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage. - Highlights: ► With MCNPX code realistic models of two LINACs were built. ► Photon and neutron spectra below the flattening filter and at the isocenter were calculated. ► Neutron spectrum at the flattening filter was compared against the Tosi et al. source-term model. ► Tosi et al. model underestimates the neutron contribution below 1 MeV. ► Photon spectra look alike to those published in literature.

  4. Saturated two-photon resonance ionization of He(21S)

    We have developed a photoionization method for complete conversion of a quantum-selected population to ionization, making possible sensitive and absolute measurement of the selected populations in a gas. Each photoionization involves the absorption of two photons (from a pulsed dye laser), one of which is resonant with an intermediate state. In this demonstration we measured the absolute number of He(21S) states per ion pair following interaction of pulses of 2-MeV photons with He

  5. Liquid xenon scintillation: photon yield and Fano factor measurements

    This paper presents a new measurement of the photon yield and the first measurement of the Fano factor in liquid xenon with a photomultiplier as photodetector. The observed photoelectron yield is 3.2/MeV which, after correction for detector solid angle and efficiency, corresponds to 78 600 photons/MeV. The Fano factor observed, Fs=0.033±0.045, agrees with the value measured in the gaseous state by other authors. ((orig.))

  6. Photon-Photon Interaction in a Photon Gas

    Thoma, Markus H.

    2000-01-01

    Using the effective Lagrangian for the low energy photon-photon interaction the lowest order photon self energy at finite temperature and in non-equilibrium is calculated within the real time formalism. The Debye mass, the dispersion relation, the dielectric tensor, and the velocity of light following from the photon self energy are discussed. As an application we consider the interaction of photons with the cosmic microwave background radiation.

  7. Photon-Photon Scattering at the Photon Linear Collider

    Jikia, G.; Tkabladze, A.

    1993-01-01

    Photon-photon scattering at the Photon Linear Collider is considered. Explicit formulas for helicity amplitudes due to $W$ boson loops are presented. It is shown that photon-photon scattering should be easily observable at PLC and separation of the $W$ loop contribution (which dominates at high energies) will be possible at $e^+e^-$ c.m. energy of 500~GeV or higher.

  8. An all-optical table-top collider for testing $\\gamma\\gamma\\rightarrow\\gamma\\gamma$ scattering in the region of MeV

    Homma, Kensuke; Nakajima, Kazuhisa

    2015-01-01

    Photon-photon scatterings contain rich information on the two-photon coupling to a virtual $e^+e^-$ pair in QED and also the coupling to known resonance states in the context of QCD and the electroweak interaction. Moreover, discovering weakly-coupling resonance states over many orders of magnitude on the mass scale can provide us hints on something dark in the Universe. The perturbative QED calculations manifestly predict the maximized cross section at the MeV scale, however, any examples of real-photon - real-photon scattering have not been observed in that energy scale hitherto. Hence, we propose the direct measurement with the maximized cross-section at the center-of-mass energy of 1-2 MeV to establish the firm footing at the MeV scale. Given currently state-of-the-art high power lasers, the QED-based elastic scattering may be observed at a reasonable rate, if a photon-photon collider exploiting $\\gamma$-rays generated by the inverse Compton process with electrons delivered from laser-plasma accelerators ...

  9. Generation and application of 15 to 30 MeV parametric X-ray by linac

    Akimoto, T

    2002-01-01

    15 to 30 MeV parametric X-ray (PXR) was generated using Si single crystal by 45 MeV electron LINAC. To obtain good monochromatic hard X-ray field, the appropriate conditions were determined by theoretical analysis and experiments. The intensity of PXR was increased with increasing electron energy and crystal rotation angle. However, PXR energy is independent of electron energy. By increasing measurement angle, energy of PXR decreased, but its intensity increased. 15 to 30 keV PXR energy and about 10 sup - sup 5 to 10 sup - sup 6 photon/electron of intensity were observed at 15 to 22 deg detection angle under the operation conditions of 45 MeV electron energy and 4 to 8 nA of beam current. The mass attenuation coefficient of photon of Zr, Nb and Mo, in K absorption edge was measured. Application to determine lattice distortion of target sample and off-angle of crystal was investigated. Generation and detection of PXR, measurement of characteristic properties: crystal rotation angle, detection angle, electron e...

  10. Measures of gamma rays between 0,3 MeV and 3,0 MeV and of the 0,511 MeV annihilation line coming from Galactic Center Region

    The detection of the flux of the electron-positron annihilation line coming from the Galactic Center direction allows one to estimate the rate of positrons production and the corresponding luminosity. The results of measurements of the annihilation line flux intensity at 0.511 MeV, obtained with a balloon borne experiment to measure gamma rays in the energy interval 0.3 to 3 MeV are presented. The detector looked at the galactic disk in the longitude interval -310 0 and observed a flux intensity of (6.70 +- 0.85) x 10-3 photons cm-2 s-1, which is in good agreement with the flux value estimated assuming that the Galactic Center is a line source emitting uniformly. Some likely sources of positrons and annhilation regions are also discussed. The results for the continuum spectrum emitted from the Galactic Center in the energy interval 0.3 to 0.67 MeV are presented and compared with measurements had already made. (Author)

  11. Dark photons from charm mesons at LHCb

    Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei

    2015-12-01

    We propose a search for dark photons A' at the LHCb experiment using the charm meson decay D*(2007 )0→D0A'. At nominal luminosity, D*0→D0γ decays will be produced at about 700 kHz within the LHCb acceptance, yielding over 5 trillion such decays during Run 3 of the LHC. Replacing the photon with a kinetically mixed dark photon, LHCb is then sensitive to dark photons that decay as A'→e+e-. We pursue two search strategies in this paper. The displaced strategy takes advantage of the large Lorentz boost of the dark photon and the excellent vertex resolution of LHCb, yielding a nearly background-free search when the A' decay vertex is significantly displaced from the proton-proton primary vertex. The resonant strategy takes advantage of the large event rate for D*0→D0A' and the excellent invariant-mass resolution of LHCb, yielding a background-limited search that nevertheless covers a significant portion of the A' parameter space. Both search strategies rely on the planned upgrade to a triggerless-readout system at LHCb in Run 3, which will permit the identification of low-momentum electron-positron pairs online during data taking. For dark photon masses below about 100 MeV, LHCb can explore nearly all of the dark photon parameter space between existing prompt-A' and beam-dump limits.

  12. Photon detectors

    Va`vra, J.

    1995-10-01

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF{sub 2} windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission.

  13. Nanowire photonics

    Peter J. Pauzauskie; Peidong Yang

    2006-01-01

    The development of integrated electronic circuitry ranks among the most disruptive and transformative technologies of the 20th century. Even though integrated circuits are ubiquitous in modern life, both fundamental and technical constraints will eventually test the limits of Moore's law. Nanowire photonic circuitry constructed from myriad one-dimensional building blocks offers numerous opportunities for the development of next-generation optical information processors and spectroscopy. Howev...

  14. Topological photonics

    Lu, Ling; Joannopoulos, John D.; Soljačić, Marin

    2014-01-01

    The application of topology, the mathematics of conserved properties under continuous deformations, is creating a range of new opportunities throughout photonics. This field was inspired by the discovery of topological insulators, in which interfacial electrons transport without dissipation, even in the presence of impurities. Similarly, the use of carefully designed wavevector-space topologies allows the creation of interfaces that support new states of light with useful and interesting prop...

  15. Photon detectors

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF2 windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission

  16. Photon locking

    Sleva, E. T.; Xavier, I. M., Jr.; Zewail, A.H.

    1986-01-01

    A novel observation of photon locking—the optical analog of spin locking—is reported, demonstrating the applicability of phase-coherent pulse sequences. The experiments are reported for the optical transition of iodine gas at 589.7 nm using the pulse sequence XYX-XYX̄. Locking decay rates are presented as a function of pressure and compared with optical dephasing (echo-decay) rates.

  17. Photon findings

    Urbina, Victor M.

    2000-01-01

    Two experiments were made using a microwave generator, which sent a narrow beam, through a metallic plate with horizontal movement. At the other end a horn antenna coupled to a field-strength detector. In linear polarization double cycloids paths were found and in circular polarization spiral paths were found. These experiments suggested that the photon is composed by two particles in dynamic equilibrium. The description of this model is given later as well as its parameters.

  18. Two-photon radiation in the 90Zr 0+→0+ transition

    An experiment on studying two-photon radiation in 0+→0+-transition with 1.76 MeV of 90Zr is described. Ratio of two-photon process and pair conversion probabilities Wγγ/Wπ=(7.4±1.4)x10-4 is obtained

  19. Study of spin-isospin states in 1213Cγπ+ reactions using tagged photons

    Positive photopions from 1213C(γπ+)1213B were measured at the tagged photon facilities of Saskatchewan Accelerator Laboratory. The pions produced by tagged photons (169 ≤ Eγ ≤ 217 MeV) were detected by a system of plastic scintillator ΔE-E telescopes at five angles from 35 degrees to 145 degrees. Enriched (99%) 13C and graphite targets were used. The pion spectra show strong transitions leading to g.s., 4.5, 7.5 and 10 MeV states in 12B and g.s., 3.5, 6.4, 9.5 and 13 MeV states in 13B. Differential cross sections at the mean tagged photon energy 191 MeV will be shown

  20. Elastic Photon Differential Cross-Sections for Helium Near the Delta Resonance.

    Delli Carpini, Domenico

    A complete angular distribution of coherent photon scattering off ^4He was measured at average laboratory bremsstrahlung energies of 187 MeV, 235 MeV and 282 MeV. The experiment was performed at the Saskatchewan Accelerator Laboratory using their new high duty factor electron beam. The scattered photons were observed with a high resolution NaI(Tl) total absorption scintillation detector. The energy resolution was sufficient to exclude photons from pi^0 decay and inelastic Compton scattering. These measurements test the Delta-hole formalism for this reaction and investigate modification of the Delta properties in a nuclear environment. The results are compared to theoretical calculations in the isobar-hole model. Clear deviations from the theory are evident for all the energies, especially at 187 MeV.

  1. 3D imaging using combined neutron-photon fan-beam tomography: A Monte Carlo study.

    Hartman, J; Yazdanpanah, A Pour; Barzilov, A; Regentova, E

    2016-05-01

    The application of combined neutron-photon tomography for 3D imaging is examined using MCNP5 simulations for objects of simple shapes and different materials. Two-dimensional transmission projections were simulated for fan-beam scans using 2.5MeV deuterium-deuterium and 14MeV deuterium-tritium neutron sources, and high-energy X-ray sources, such as 1MeV, 6MeV and 9MeV. Photons enable assessment of electron density and related mass density, neutrons aid in estimating the product of density and material-specific microscopic cross section- the ratio between the two provides the composition, while CT allows shape evaluation. Using a developed imaging technique, objects and their material compositions have been visualized. PMID:26953978

  2. Praseodymium activation detector for measuring bursts of 14 MeV neutrons

    Meehan, Tim, E-mail: meehanbt@nv.doe.go [National Security Technologies, LLC, P.O. Box 98521, North Las Vegas, NV 89030 (United States); Hagen, E.C. [National Security Technologies, LLC, P.O. Box 98521, North Las Vegas, NV 89030 (United States); Ruiz, C.L.; Cooper, G.W. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)

    2010-08-21

    A new, accurate, neutron activation detection scheme for measuring pulsed neutrons has been designed and tested. The detection system is sensitive to neutrons with energies above 10 MeV; importantly, it is insensitive to gamma radiation <10 MeV and to lower-energy (e.g., fission and thermal) neutrons. It is based upon the use of {sup 141}Pr, an element that has a single, naturally occurring isotope, a significant n,2n cross-section, and decays by positron emission that result in two coincident 511 keV photons. Neutron fluences are thus inferred by relating measured reaction product decay activity to fluence. Specific sample activity is measured using the sum-peak method to count gamma-ray coincidences from the annihilation of the positron decay products. The system was tested using 14 and 2.45 MeV neutron bursts produced by NSTec Dense Plasma Focus Laboratory fusion sources. Lead, copper, beryllium, and silver activation detectors were compared. The detection method allows measurement of 14 MeV neutron yield with a total error of {approx}18%.

  3. Calibration processes for photon-photon colliders

    Bartos, E.; Dubnickova, A. -Z.; Galynskii, M. V.; Kuraev, E. A.

    2003-01-01

    Processes with creation of a pair charged particles with emission of hard photon and two pairs of charged particles are considered for colliding partially polarized photon photon beams. The effects of circular and linear polarization of the initial photons are discussed in more details.

  4. Calibration processes for photon-photon colliders

    Bartos, E; Galynsky, M V; Kuraev, E A

    2004-01-01

    Processes with creation of a pair charged particles with emission of hard photon and two pairs of charged particles are considered for colliding partially polarized photon photon beams. The effects of circular and linear polarization of the initial photons are discussed in more detail.

  5. Semiconductor quantum optics with tailored photonic nanostructures

    Laucht, Arne

    2011-06-15

    This thesis describes detailed investigations of the effects of photonic nanostructures on the light emission properties of self-assembled InGaAs quantum dots. Nanoscale optical cavities and waveguides are employed to enhance the interaction between light and matter, i.e. photons and excitons, up to the point where optical non-linearities appear at the quantum (single photon) level. Such non-linearities are an essential component for the realization of hardware for photon based quantum computing since they can be used for the creation and detection of non-classical states of light and may open the way to new genres of quantum optoelectronic devices such as optical modulators and optical transistors. For single semiconductor quantum dots in photonic crystal nanocavities we investigate the coupling between excitonic transitions and the highly localized mode of the optical cavity. We explore the non-resonant coupling mechanisms which allow excitons to couple to the cavity mode, even when they are not spectrally in resonance. This effect is not observed for atomic cavity quantum electrodynamics experiments and its origin is traced to phonon-assisted scattering for small detunings ({delta}E<{proportional_to}5 meV) and a multi-exciton-based, Auger-like process for larger detunings ({delta}E >{proportional_to}5 meV). For quantum dots in high-Q cavities we observe the coherent coupling between exciton and cavity mode in the strong coupling regime of light-matter interaction, probe the influence of pure dephasing on the coherent interaction at high excitation levels and high lattice temperatures, and examine the coupling of two spatially separated quantum dots via the exchange of real and virtual photons mediated by the cavity mode. Furthermore, we study the spontaneous emission properties of quantum dots in photonic crystal waveguide structures, estimate the fraction of all photons emitted into the propagating waveguide mode, and demonstrate the on-chip generation of

  6. Status of the Advanced Photon Source (APS) linear accelerator

    A 2856-MHz S-band, 450-MeV electron/positron linear accelerator is the first part of the injector for the Advanced Photon Source (APS) 7-GeV storage ring. Construction of the APS linac is currently nearing completion, and commissioning will begin in July 1993. The linac and its current status are discussed in this paper

  7. 14 MeV proton activation analysis

    A fast nuclear nondestructive method for protein analysis using the 14 MeV proton activation has been developed. The total nitrogen content was measured through the reaction: 14N (p,n) 14O, (Tsub(1/2)=71 s). The 14O activity was detected by means of its characteristic 2.312 MeV gamma-ray line with a NaI(Tl) detector. For a fast determination of a large number of samples a mechanized sistem reacting a rate of one sample per minute has been developed. The laboratory electronics comprises a multichannel analyser, a PDP computer and an electronic module comtroller. Comparison of the results obtained by the method described and the classical Kjeldal technique for samples of various cereal grains (soya bean seads, wheat, barley and corn) showed good correlation. A problem of the analysis of the whole protein region on corn and soya-bean seads, where this region is thicker (0,2 - 2 mm), is mentioned. In this case flour was proposed to be used to obtain a protein homogeneous sample and the irradiaton dose for a sample was about 33,000 Gy, mainly (99%) from protons (27 s x 100 nA x 14 MeV)

  8. Modeling the Bremsstrahlung of 30-60 MeV electrons. Source term calculation

    The photofission process has been recently considered for the production of neutron rich isotopes and the development of radioactive beams. The radioprotection hazard should be studied accordingly. A survey of the radiative electron energy loss theory is reported in order to estimate numerically the Bremsstrahlung production of thick targets. The resulted Bremsstrahlung angular and energy theoretical distributions delivered from W and UCx thick converters are presented and compared with previous results. This study is focused on initial kinetic energies of the electron beam included in the range 30-60 MeV, suitable for the production of large photon yields able to induce the 238U fission. The source term for 50 MeV incident electrons is reported for radioprotection purposes. (authors)

  9. Virtual photon-photon scattering

    Hoferichter, Martin; Colangelo, Gilberto; Procura, Massimiliano; Stoffer, Peter(Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, Bern, CH-3012, Switzerland)

    2014-01-01

    Based on analyticity, unitarity, and Lorentz invariance the contribution from hadronic vacuum polarization to the anomalous magnetic moment of the muon is directly related to the cross section of e+e− → hadrons. We review the main difficulties that impede such an approach for light-by-light scattering and identify the required ingredients from experiment. Amongst those, the most critical one is the scattering of two virtual photons into meson pairs. We analyze the analytic structure of the pr...

  10. Virtual photon-photon scattering

    Hoferichter, Martin; Colangelo, Gilberto; Procura, Massimiliano; Stoffer, Peter(Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, Bern, CH-3012, Switzerland)

    2013-01-01

    Based on analyticity, unitarity, and Lorentz invariance the contribution from hadronic vacuum polarization to the anomalous magnetic moment of the muon is directly related to the cross section of e^+e^- --> hadrons. We review the main difficulties that impede such an approach for light-by-light scattering and identify the required ingredients from experiment. Amongst those, the most critical one is the scattering of two virtual photons into meson pairs. We analyze the analytic structure of th...

  11. Photons and photoneutrons spectra of a Linac of 15 MV

    Using the Monte Carlo code MCNP-5, the photons and photoneutrons spectra generated in the head stock of the lineal accelerator (Linac) Varian of 15 MV of the Cancerology State of Nayarit were determined. For the calculations a heterogeneous head stock was modeled, more compatible with the work conditions. In the center of the head stock a tungsten target was located on a copper support, followed by the flattened filter. The photons and photoneutrons spectra were obtained accelerating electrons and making them collide against the target to produce photons by Bremsstrahlung, these photons were transported inside the head stock and the photons and photoneutrons spectra were calculated in a punctual detector located under the flattened filter and in the isocenter. The spectra were evaluated in punctual detectors that were located in the plane from the isocenter to the long of the X and Y axes each 20 cm, in an equidistant way, up to 2 m, so much in the longitudinal and transversal axes. In the calculations were used histories 5E(6) with the purpose of obtaining smaller uncertainties to 1%. It was found that the photons spectrum in the punctual detector inside the head stock presents a pick of 1.25 MeV in the energy interval of 0.5 and 1.5 MeV, later suffers a filtration and diminishes in asymptote form. This spectrum modifies when the beam reaches the isocenter, diminishing the low energy photons. Inside the head stock the photoneutrons spectrum shows a structure with two picks, one before 1 MeV and other after 1 MeV; this is for effect of the collimators geometry and the distance. Finally an increment of the total neutrons flow to 60 cm of distance of the isocenter on the Y axis was observed, due to the design geometry of the modeling heterogeneous head stock. (Author)

  12. Nanowire photonics

    Peter J. Pauzauskie

    2006-10-01

    Full Text Available The development of integrated electronic circuitry ranks among the most disruptive and transformative technologies of the 20th century. Even though integrated circuits are ubiquitous in modern life, both fundamental and technical constraints will eventually test the limits of Moore's law. Nanowire photonic circuitry constructed from myriad one-dimensional building blocks offers numerous opportunities for the development of next-generation optical information processors and spectroscopy. However, several challenges remain before the potential of nanowire building blocks is fully realized. We cover recent advances in nanowire synthesis, characterization, lasing, integration, and the eventual application to relevant technical and scientific questions.

  13. Active neutron/photon personal dosemeters

    Though active personal dosemeters for photon fields reflect already a high level of development, there is still a need to advance the design of dosemeters for use in mixed neutron/photon fields and especially for monitoring the staff of nuclear power plants and the personnel accompanying transports of spent fuel flasks. The measurement of the neutron component is usually associated with problems. After a short description of the complex mixed fields in the nuclear fuel cycle, the commercially available active dosemeters and those under development will be listed and problems arising from their use in these fields will be discussed. Two new developments, the Siemens EPD-N2 and the PTB DOS-2002, which both are capable of indicating neutron and photon doses, will be described and discussed in detail. New response functions with respect to personal dose equivalent Hp(10) will be presented for neutrons. They have been determined by measurements in the quasi-monoenergetic reference fields at PTB in the energy range from 24 keV to 14.8 MeV and in fields with broad spectral distributions using the radionuclide sources 252Cf(bare), 252Cf(D2O,mod) - with and without cadmium shielding - 241Am-Be as well as a thermal neutron beam. The spectral distributions of all fields and the readings of the dosemeters in these fields were taken as inputs for an unfolding procedure to determine the dosemeter response in the overall energy region from thermal to 15 MeV. The procedure was tested by folding the dosemeter response with the broad neutron spectra and comparing with the readings of the dosemeters. Another problem in practical workplace fields is linked with high energy photons. Photons with energies from 6 MeV to 7 MeV from the 16O(n,pγ) reaction contribute to dose, particularly at reactors, and have to be taken into account when dosemeters are processed. Measurements with high energy photons were therefore performed with both devices and will be discussed. Finally, practical

  14. Photon spectrometry in thermal neutron standard field

    Kudo, K; Koshikawa, S; Toyokawa, H; Ohgaki, H; Matzke, M

    2002-01-01

    An NE213 liquid scintillation counter (5.08 cm in diameter and 5.08 cm long) with an LiF filter was used to measure the energy distribution of photons mixed in a thermal neutron field. The response function matrix of photons in an energy range up to 10 MeV was calculated by the EGS4/PRESTA code and properly folded with a resolution function. Pulse height spectra measured with a set of reference gamma-ray sources were compared to the calculated response function and agreed very well for all reference gamma-ray sources. The GRAVEL and MIEKE codes from the HEPRO program were used to unfold measured pulse height spectra. Energy distributions obtained by the unfolding were applied to evaluate the effective dose equivalent of photons mixed in a thermal neutron field.

  15. Optimal generation of indistinguishable photons from non-identical artificial molecules

    Cancellieri, E.; Troiani, F.; Goldoni, G.

    2009-01-01

    We show theoretically that nearly indistinguishable photons can be generated with non-identical semiconductor-based sources. The use of virtual Raman transitions and the optimization of the external driving fields increases the tolerance to spectral inhomogeneity to the meV energy range. A trade-off emerges between photon indistinguishability and efficiency in the photon-generation process. Linear (quadratic) dependence of the coincidence probability within the Hong-Ou-Mandel setup is found w...

  16. A numerical study of the characteristics of the LEALE photon beam

    At the LEALE laboratory a monochromatic photon beam with energy in the range 80/300 MeV is available. Photons are produced by positron annihilation on a liquid hydrogen target. The characteristics of the beam are calculated for various conditions (positron energy, photon collimator, target thickness), taking into account the effects contributing to the beam spreading (energy loss and multiple scattering of protons in the annihilation target, energy distribution and angular divergence of the positron beam). (author)

  17. High intensity X/γ photon beams for nuclear physics and photonics

    Serafini, L.; Alesini, D.; Bacci, N.; Bliss, N.; Cassou, K.; Curatolo, C.; Drebot, I.; Dupraz, K.; Giribono, A.; Petrillo, V.; Palumbo, L.; Vaccarezza, C.; Variola, A.; Zomer, F.

    2016-05-01

    In this manuscript we review the challenges of Compton backscattering sources in advancing photon beam performances in the 1 - 20 MeV energy range, underlining the design criteria bringing to maximum spectral luminosity and briefly describing the main achievements in conceiving and developing new devices (multi-bunch RF cavities and Laser recirculators) for the case of ELI-NP Gamma Beam System (ELI-NP-GBS).

  18. High intensity X/γ photon beams for nuclear physics and photonics

    Serafini L.

    2016-01-01

    Full Text Available In this manuscript we review the challenges of Compton backscattering sources in advancing photon beam performances in the 1 – 20 MeV energy range, underlining the design criteria bringing to maximum spectral luminosity and briefly describing the main achievements in conceiving and developing new devices (multi-bunch RF cavities and Laser recirculators for the case of ELI-NP Gamma Beam System (ELI-NP-GBS.

  19. Geant4-based comprehensive study of the absorbed fraction for electrons and gamma-photons using various geometrical models and biological tissues

    Rahman Ziaur; Rehman Shakeel Ur.; Mirza Sikander M.; Arshed Waheed; Mirza Nasir M.

    2013-01-01

    The Geant4-based comprehensive model has been developed to predict absorbed fraction values for both electrons and gamma photons in spherical, ellipsoidal, and cylindrical geometries. Simulations have been carried out for water, ICRP soft-, brain-, lung-, and ICRU bone tissue for electrons in 0.1 MeV-4 MeV and g-photons in the 0.02 MeV-2.75 MeV energy range. Consistent with experimental observations, the Geant4-simulated values of absorbed fractions show a ...

  20. Evidence for Gamma-Ray Flares in 3C 279 and PKS 1622-297 at ~10 MeV

    Collmar, W; Blömen, H; Blom, J J; Hermsen, W; McConnell, M; Stacy, J G; Bennett, K; Williams, O R

    1997-01-01

    The EGRET experiment aboard the Compton Gamma-Ray Observatory (CGRO) has observed at energies above 100 MeV strong gamma-ray flares with short-term time variability from the gamma-ray blazars 3C 279 and PKS 1622-297. During these flaring periods both blazars have been detected by the COMPTEL experiment aboard CGRO at photon energies of about 10 MeV, revealing simultaneous gamma-ray activity down to these energies. For both cases the derived fluxes exceed those measured in previous observations, and 3C 279 shows an indication for time variability within the observational period. Both sources show evidence for `hard' MeV spectra. In general the behaviour of both sources at gamma-ray energies is found to be quite similar supporting the conclusion that the underlying physical mechanism for both gamma-ray flares might be the same.

  1. Reaction mechanisms in 12C(γ,pp) near 200 MeV

    Inclusive 12C(γ,pp) cross sections have been measured with tagged photons in the range Eγ=187 endash 227 MeV using the Saskatchewan-Alberta Large Acceptance Detector (SALAD). The large angular acceptance allowed the measurement of noncoplanar pp emission. The cross sections were compared to a Monte Carlo intranuclear cascade calculation. Agreement was reasonable for the shapes of the cross sections but the calculated total cross section was 3.9 times larger than the data. copyright 1996 The American Physical Society

  2. Measurement of eta photoproduction on the proton from threshold to 1500 MeV

    Bartalini, O.; Bellini, V.; Bocquet, J.P.; Calvat, P.; Capogni, M.; Casano, L.; Castoldi, M; D'Angelo, A.(Università di Roma Tor Vergata and INFN, Sezione di Roma Tor Vergata, Rome, Italy); Didelez, J. P.; Di Salvo, R.; Fantini, A.; Franco, D.(APC, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France); Gaulard, C.; Gervino, G.; Ghio, F.

    2007-01-01

    Beam asymmetry and differential cross section for the reaction gamma+p->eta+p were measured from production threshold to 1500 MeV photon laboratory energy. The two dominant neutral decay modes of the eta meson, eta->2g and eta->3pi0, were analyzed. The full set of measurements is in good agreement with previously published results. Our data were compared with three models. They all fit satisfactorily the results but their respective resonance contributions are quite different. The possible ph...

  3. Angular distribution of photofission fragments in 238U at 5.43 MeV

    The angular distribution of photofission fragments of 238U, produced by 5.43 MeV monochromatic photons from the η,γ reaction in sulphur, has been measured using glass plates as detectors. In the analysis of the results only the contributions from the (Jπ, K) 1= (1-,0), (1-,1) and (2+,0) terms were considered. The coefficients of the angular distributions of the fission fragments were obtained. An analysis of the data available in the literature on the angular distribution near the photofission threshold is also presented. (author)

  4. Total photoabsorption cross sections for 1H, 2H and 3He from 200 to 800 MeV

    The total photoabsorption cross sections for 1H, 2H and 3He have been measured for incident photon energies ranging from 200 to 800 MeV. The results show clearly the changes in the nucleon resonances in going from 1H to 3He. In particular, for the D13 region the behaviour for 3He is intermediate between that for 1H, 2H and heavier nuclei. (author)

  5. A 50-MeV mm-wave electron linear accelerator system for production of tunable short wavelength synchrotron radiation

    The Advanced Photon Source (APS) at Argonne in collaboration with the University of Illinois at Chicago and the University of Wisconsin at Madison is developing a new millimeter wavelength, 50-MeV electron linear accelerator system for production of coherent tunable wavelength synchrotron radiation. Modern micromachining techniques based on deep etch x-ray lithography, LIGA (Lithografie, Galvanoformung, Abformung), capable of producing high-aspect ratio structures are being considered for the fabrication of the accelerating components

  6. Response of monitoring instruments to high-energy photon radiation

    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.

  7. Nuclear Photonics

    Habs, D; Jentschel, M; Thirolf, P G

    2012-01-01

    With new gamma-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest with 10^13 g/s and a bandwidth of Delta E_g/E_g ~10^-3, a new era of g-beams with energies <=20 MeV comes into operation, compared to the present world-leading HIGS facility (Duke Univ., USA) with 10^8 g/s and Delta E_g/E_g~0.03. Even a seeded quantum FEL for g-beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused g-beams. We describe a new experiment at the g-beam of the ILL reactor (Grenoble), where we observed for the first time that the index of refraction for g-beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for g-beams are being developed. Thus we have to optimize the system of the g-beam facility, the g-beam optics and g-detectors. We can trade g-intensity for band width, going down to Delta E_g/E_g ~ 10^-6 and address individual nuclear levels. 'Nuclear pho...

  8. The low energy photon tagger NEPTUN: Toward a detailed study of the Pygmy dipole resonance with real photons

    Semmler, Diego; Aumann, T.; Bauer, C.; Baumann, M.; Beckstein, M.; Beller, J.; Blecher, A.; Cvejin, N.; Duchene, M.; Hug, F.; Kahlbow, J.; Knoerzer, M.; Kreis, K.; Kremer, C.; Ries, P.; Romig, C.; Scheit, H.; Schnorrenberger, L.; Symochko, D.; Walz, C. [Institut fuer Kernphysik, Darmstadt (Germany); Lefol, R. [University of Saskatchewan, Saskatoon (Canada); Loeher, B. [ExtreMe Matter Institute EMMI and Research Division, Frankfurt (Germany); Institute for Advanced Studies FIAS, Frankfurt (Germany)

    2014-07-01

    The low energy photon tagger NEPTUN at the S-DALINAC delivers a quasi-monoenergetic photon beam between about 4 MeV and 20 MeV with a resolution of approximately 25 keV. Tagged photons provide the possibility to measure the dipole strength of nuclei in the energy range below and above the neutron threshold. The highly efficient LaBr{sub 3} based spectrometer GALATEA will be used to detect not only the direct decays to the ground state, but also cascading decays can be measured with suitable efficiency. We will measure (γ,n)- and (γ,nγ)-reactions with neutron detectors based on plastic scintillators. This talk provides an overview about setup and goals of the NEPTUN experiment as well as the current state of the commissioning phase. Planned optimizations of the setup, based on the results of a test beam time in June 2013, are also presented.

  9. Photon mapping

    Nečas, Ondřej

    2009-01-01

    V rámci této práce byla provedena praktická implementace algoritmu photon mapping. Pro dosažení kvalitnějšího výstupu byly zkoumány některé základní a pokročilejší metody globálního osvětlení. Tyto náročné algoritmy jsou často prakticky nepoužitelné a je nutná jejich optimalizace. Základem praktické implementace je optimalizace raytraceru. Vzorky nepřímého difuzního osvětlení počítané metodou Monte Carlo je možné mezi sebou interpolovat s použitím vhodné techniky....

  10. Production of high energy photon beam at TAC

    When an electron pass through an electric field, the electron loose its part of energy and photon is generated. This process is known as Bremsstrahlung (means 'radiation breaking' in German) and this photon can be used in a variety of different application. The TAC will be first Turkish Accelerator Center (TAC) where a IR-FEL and Beamstrahlung photon beam facilities will be established in first stage. The electrons will be accelerated up to 40 MeV by two LINAC and these beam will be used to generate Bremsstrahlung photon. In this study, the main parameters for Bremsstrahlung photon beam facility will be established at TAC will be detailed and fields to be used Bremsstrahlung beam will also be presented.

  11. Supernova bounds on the dark photon using its electromagnetic decay

    The hypothetical massive dark photon (γ′) which has kinetic mixing with the SM photon can decay electromagnetically to e+e− pairs if its mass m exceeds 2me, and otherwise into three SM photons. These decays yield cosmological and supernovae associated signatures. We briefly discuss these signatures, particularly in connection with the supernova SN1987A, and delineate the extra constraints that arise on the mass and mixing parameter of the dark photon. In particular, we find that for dark photon mass mγ′ in the 5–20 MeV range arguments based on supernova 1987A observations lead to a bound on ϵ which is about 300 times stronger than the presently existing bounds based on energy loss arguments

  12. Photon Aided and Inhibited Tunneling of Photons

    liu, xuele

    2013-01-01

    In the light of the interest in the transport of single photons in arrays of waveguides, fiber couplers, photonic crystals, etc., we consider the quantum mechanical process of the tunneling of photons through evanescently or otherwise coupled structures. We specifically examine the issue of tunneling between two structures when one structure already contains few photons. We demonstrate the possibility of both photon aided and inhibited tunneling of photons. The Bosonic nature of photons enhances the tunneling probability. We also show how the multiphoton tunneling probability can be either enhanced or inhibited due to the presence of photons. We find similar results for the higher order tunneling. Finally, we show that the presence of a squeezed field changes the nature of tunneling considerably.

  13. Physics at high energy photon photon colliders

    I review the physic prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking

  14. Physics at High Energy Photon Photon Colliders

    Chanowitz, Michael S.

    1994-01-01

    I review the physics prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking.

  15. ETAII 6 MEV PEPPERPOT EMITTANCE MEASUREMENT

    Paul, A C; Richardson, R; Weir, J

    2004-10-18

    We measured the beam emittance at the ETAII accelerator using a pepper-pot diagnostic at nominal parameters of 6 MeV and 2000 Amperes. During the coarse of these experiments, a ''new tune'' was introduced which significantly improved the beam quality. The source of a background pedestal was investigated and eliminated. The measured ''new tune'' emittance is {var_epsilon}= 8.05 {plus_minus} 0. 53 cm - mr or a normalized emittance of {var_epsilon}{sub n} = 943 {plus_minus} 63 mm - mr In 1990 the ETAII programmatic emphasis was on free electron lasers and the paramount parameter was whole beam brightness. The published brightness for ETAII after its first major rebuild was J = 1 - 3 x 10{sup 8} A/(m - rad){sup 2} at a current and energy of 1000-1400 Amperes and 2.5 MeV. The average normalized emittance derived from table 2 of that report is 864 mm-mr corresponding to a real emittance of 14.8 cm-mr.

  16. High Energy Photon-Photon Collisions -

    Brodsky, Stanley J.; SLAC; Zerwas, Peter M.; DESY

    1994-01-01

    The collisions of high energy photons produced at an electron-positron collider provide a comprehensive laboratory for testing QCD, electroweak interactions, and extensions of the Standard Model. The luminosity and energy of the colliding photons produced by back-scattering laser beams is expected to be comparable to that of the primary $e^+e^-$ collisions. In this overview, we shall focus on tests of electroweak theory in photon-photon annihilation, particularly $\\gamma\\gamma \\rightarrow W^+...

  17. Polarization precession in photon-photon encounters

    Sawyer, R. F.

    2004-01-01

    We calculate the rate of precession of the direction of polarization of a photon traversing a sea of plane-polarized photons moving in the opposed direction, where the interaction is the one-loop "vacuum" Heisenberg-Euler coupling of four fields. Substantial precession can take place in a distance many orders of magnitude shorter than the free path for photon-photon scattering, mediated by the same interaction. We consider briefly the possibility of some interesting collective effects in the ...

  18. Total cross section of hadron photoproduction on Be, C, Hsub(2)O and Al nuclei in the energy range Esub(γ)=(200-900) MeV

    New experimental results of the measurement of total cross section of hadron photoproduction on Be, C, H2O and Al nuclei for the photon energy of (0.2-0.9) GeV obtained on the tagged photon beam by means of hadron detectors covering the solid angle approximately 4π are reported. The results are compared with the available data on total cross section of hadron photoproduction. For the oxygen nucleus the comparison is carried out with the theoretical predictions for the photon energy up to 400 MeV

  19. Jets in Photon-Photon Collisions

    Fontannaz, M.

    1994-01-01

    We study jet production in photon-photon reactions at the next-to-leading logarithm accuracy. The discussion of the theoretical uncertainties and the role of the quark and gluon distributions in the photon is emphasized. The phenomenology at TRISTAN energies is discussed and predictions are made for LEP 200.

  20. Suzaku Observations of Extreme MeV Blazar SWIFT J0746.3+2548

    Watanabe, Shin; Takahashi, Tadayuki; Kataoka, Jun; Madejski, Greg; Sikora, Marek; Tavecchio, Fabrizio; Sambruna, Rita; Romani, Roger; Edwards, Philip G; Pursimo, Tapio

    2008-01-01

    We report the Suzaku observations of the high luminosity blazar SWIFT J0746.3+2548 (J0746) conducted in November 2005. This object, with z = 2.979, is the highest redshift source observed in the Suzaku Guaranteed Time Observer (GTO) period, is likely to show high gamma-ray flux peaking in the MeV range. As a result of the good photon statistics and high signal-to-noise ratio spectrum, the $Suzaku$ observation clearly confirms that J0746 has an extremely hard spectrum in the energy range of 0.3-24 keV, which is well represented by a single power-law with a photon index of 1.17 and Galactic absorption. The multiwavelength spectral energy distribution of J0746 shows two continuum components, and is well modeled assuming that the high-energy spectral component results from Comptonization of the broad-line region photons. In this paper we search for the bulk Compton spectral features predicted to be produced in the soft X-ray band by scattering external optical/UV photons by cold electrons in a relativistic jet. W...

  1. Suzaku Observations of Extreme MeV Blazar Swift J0746.3+2548

    Watanabe, Shin; Sato, Rie; Takahashi, Tadayuki; Kataoka, Jun; Madejski, Greg; Sikora, Marek; Tavecchio, Fabrizio; Sambruna, Rita; Romani, Roger; Edwards, Philip G.; Pursimo, Tapio

    2008-12-01

    We report the Suzaku observations of the high luminosity blazar SWIFT J0746.3+2548 (J0746) conducted in November 2005. This object, with z = 2.979, is the highest redshift source observed in the Suzaku Guaranteed Time Observer (GTO) period, is likely to show high gamma-ray flux peaking in the MeV range. As a result of the good photon statistics and high signal-to-noise ratio spectrum, the Suzaku observation clearly confirms that J0746 has an extremely hard spectrum in the energy range of 0.3-24 keV, which is well represented by a single power-law with a photon index of {Lambda}{sub ph} {approx_equal} 1.17 and Galactic absorption. The multiwavelength spectral energy distribution of J0746 shows two continuum components, and is well modeled assuming that the high-energy spectral component results from Comptonization of the broad-line region photons. In this paper we search for the bulk Compton spectral features predicted to be produced in the soft X-ray band by scattering external optical/UV photons by cold electrons in a relativistic jet. We discuss and provide constraints on the pair content resulting from the apparent absence of such features.

  2. Computational Study of Integrated Neutron/Photon Imaging for Illicit Material Detection

    Hartman, Jessica; Barzilov, Alexander

    The feasibility of integration of photon and neutron radiography for nondestructive detection of illicit materials was examined. The MCNP5 code was used to model a radiography system consisting of accelerator-based neutron and photon sources and the imaging detector array, with an object under scrutiny placed between them. For this examination, the objects consisted of a matrix of low-Z and high-Z materials of various shapes and density. Transmission-radiography computations were carried out using 2.5-MeV deuterium-deuterium and 14-MeV deuterium-tritium neutron sources, and a 0.3-MeV photon source. The radiography tallies for both neutron and photon sources were modeled for the same geometry of the system. The photon-to- neutron transmission ratios were determined for each pixel of the detector array and utilized to identify the presence of specific materials in the radiographic images. By focusing on the inherent difference between neutron and photon interactions, it was possible to determine the shape and material composition of complex objects present within a pallet or a shipping container. The use of a single imaging array of scintillation detectors for simultaneous measurements of fast neutrons and photons is discussed, and its function in the dual neutron/photon radiography applications is addressed.

  3. Shielding considerations for the 750-MeV electron accelerator at the University of Illinois

    This report summarizes some of the calculations that were carried out to provide shielding data for the 750-MeV electron accelerator under construction at the University of Illinois. All of the results described herein were obtained for a 300-MeV and/or 750-MeV electron beam. All calculations deal with doses produced by the particle beam during operation and do not include secondary radiation sources, i.e., induced radioactivity. The dose equivalents were obtained as a function of shield thickness so that various accident scenatios could be considered, i.e., various percentages of beam loss during operation. The calculated results that were considered included: (1) the earth shielding thickness (and iron door) surrounding the accelerator vault, (2) the earth shielding thickness around the beam transport tunnel, (3) an estimate of the thickness and composition of the movable shielding door in the general purpose electron beam experimental area, (4) the shield thickness around the beam dump in the bremsstrahlung irradiation facility, (5) skyshine dose from some of the experimental areas, and (6) dose rates inside and outside the tagged photon facility. The programs and cross section data bases used in the calculations, as well as the source neutron spectra calculations, are presented. The results of the dose calculations are presented and discussed

  4. RR photons

    Camara, Pablo G; Marchesano, Fernando

    2011-01-01

    Type II string compactifications to 4d generically contain massless Ramond-Ramond U(1) gauge symmetries. However there is no massless matter charged under these U(1)'s, which makes a priori difficult to measure any physical consequences of their existence. There is however a window of opportunity if these RR U(1)'s mix with the hypercharge $U(1)_Y$ (hence with the photon). In this paper we study in detail different avenues by which $U(1)_{RR}$ bosons may mix with D-brane U(1)'s. We concentrate on Type IIA orientifolds and their M-theory lift, and provide geometric criteria for the existence of such mixing, which may occur either via standard kinetic mixing or via the mass terms induced by St\\"uckelberg couplings. The latter case is particularly interesting, and appears whenever D-branes wrap torsional $p$-cycles in the compactification manifold. We also show that in the presence of torsional cycles discrete gauge symmetries and Aharanov-Bohm strings and particles appear in the 4d effective action, and that ty...

  5. Full distribution of dipole states below 9MeV in 76Se

    Cooper, N.; Werner, V.; Smith, M. K.; Goddard, P. M.; Reichel, F.; Beller, J.; Fritzsche, M.; Pietralla, N.; Romig, C.; Savran, D.; Scheck, M.; Sonnabend, K.; Wagner, J.; Chakraborty, A.; Crider, B. P.; Peters, E.; Yates, S. W.; Kelly, J.; Raut, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Deleanu, D.; Filipescu, D.; Glodariu, T.

    2011-10-01

    Systematics of photoexcitation strength near the particle emission threshold has been of great interest in recent years due its importance in stellar nucleosynthesis of certain heavy nuclei. Theories such as the QRPA and its variants are currently used to calculate photoexcitation strength in this energy region, as well as the nuclear matrix element of the hypothetical 0 ν 2 β -decay modes, such as 76Ge -->76Se + 2e- . Dipole states between 2 and 4MeV in 76Se have been studied using linearly polarized, nearly monoenergetic photons produced by Compton-backscattering at the HI γ --> S facility. The experiment completes a series of photon scattering experiments performed on this nucleus in the energy region below 9MeV, both at the S-DALINAC and at HI γ --> S. Collective dipole excitations are investigated. Supported by U.S. DOE grant nos. DE-FG02-91ER40609 and DE-FG02-97ER41033, and NSF grant no. PHY-0956310.

  6. Optomechanical photon shuttling between photonic cavities

    Li, Huan

    2014-01-01

    Mechanical motion of photonic devices driven by optical forces provides a profound means of coupling between optical fields. The current focus of these optomechanical effects has been on cavity optomechanics systems in which co-localized optical and mechanical modes interact strongly to enable wave-mixing between photons and phonons and backaction cooling of mechanical modes. Alternatively, extended mechanical modes can also induce strong nonlocal effects on propagating optical fields or multiple localized optical modes at distances. Here, we demonstrate a novel multi-cavity optomechanical device: a "photon see-saw", in which torsional optomechanical motion can shuttle photons between two photonic crystal nanocavities. The resonance frequencies of the two cavities, one on each side of the see-saw, are modulated anti-symmetrically by the device's rotation. Pumping photons into one cavity excites optomechanical self-oscillation which strongly modulates the inter-cavity coupling and shuttles photons to the other...

  7. Photon-hadron and photon-photon collisions in ALICE

    Schicker, R.

    2015-01-01

    A review is given on photon-hadron and photon-photon collisions in the ALICE experiment. The physics motivation for studying such reactions is outlined, and the results obtained in proton-lead and lead-lead collisions in Run 1 of the LHC are discussed. The improvement in detector rapidity coverage due to a newly added detector system is presented. The ALICE perspectives for data taking in LHC Run II are summarised.

  8. Status of the Advanced Photon Source (APS) linear accelerator

    A 2856-MHz S-band, electron-positron linear accelerator (linac) has been constructed at the Advanced Photon Source (APS). It is the source of particles and the injector for the other APS accelerators, and linac commissioning is well underway. The linac is operated 24 hours per day to support linac beam studies and rf conditioning, as well as positron accumulator ring and synchrotron commissioning studies. The design goal for accelerated positron current is 8-mA, and has been met. Maximum positron energy to date is 420-MeV, approaching the design goal of 450-MeV. The linac design and its performance are discussed

  9. Dark Photon Search at BABAR

    Greenwood, Ross N; /MIT /SLAC

    2012-09-07

    Presented is the current progress of a search for the signature of a dark photon or new particle using the BaBar data set. We search for the processes e{sup +}e{sup -} {yields} {gamma}{sub ISR}A{prime},A{prime} {yields} e{sup +}e{sup -} and e{sup +}e{sup -} {yields} {gamma}{sub ISR}{gamma}, {gamma} {yields} A{prime},A{prime} {yields} e{sup +}e{sup -}, where {gamma}{sub ISR} is an initial state radiated photon of energy E{sub {gamma}} >= 1 GeV. Twenty-five sets of Monte Carlo, simulating e{sup +}e{sup -} collisions at an energy of 10.58 GeV, were produced with different values of the A{prime} mass ranging from 100 MeV to 9.5 GeV. The mass resolution is calculated based on Monte Carlo simulations. We implement ROOT's Toolkit for Multivariate Analysis (TMVA), a machine learning tool that allows us to evaluate the signal character of events based on many of discriminating variables. TMVA training is conducted with samples of Monte Carlo as signal and a small portion of Run 6 as background. The multivariate analysis produces additional cuts to separate signal and background. The signal efficiency and sensitivity are calculated. The analysis will move forward to fit the background and scan the residuals for the narrow resonance peak of a new particle.

  10. Resolved Photon Processes

    Drees, Manuel; Godbole, Rohini M.(Centre for High Energy Physics, Indian Institute of Science, 560012, Bangalore, India)

    1995-01-01

    We review the present level of knowledge of the hadronic structure of the photon, as revealed in interactions involving quarks and gluons ``in" the photon. The concept of photon structure functions is introduced in the description of deep--inelastic $e \\gamma$ scattering, and existing parametrizations of the parton densities in the photon are reviewed. We then turn to hard \\gamp\\ and \\gaga\\ collisions, where we treat the production of jets, heavy quarks, hard (direct) photons, \\jpsi\\ mesons, ...

  11. Resolved Photon Processes

    Godbole, RM

    1998-01-01

    After giving a very brief introduction to the resolved photon processes, I will summarise the latest experimental information from HERA, on resolved photon contribution to large pt jet production as well as to direct photon production. I will point out the interesting role that resolved photon processes can play in increasing our understanding of the dynamics of the Quarkonium production. I will then discuss the newer information on the parton content of virtual photons as well as the kt dist...

  12. Review of neutron data: 10 to 40 MeV

    Neutron data are reviewed for incident neutron energies between 10 and 40 MeV. A census of the data shows that there are many gaps in this range and that the existing data are primarily for neutron energies around 14 MeV. Aside from total cross sections, there are few data between 10 and 13 MeV and between 15 and 40 MeV. Examples are presented to show the quality of selected data for total, elastic, inelastic, activation, and charged-particle and gamma-ray production cross sections. The spectra of emitted particles are also discussed

  13. 14 MeV neutrons physics and applications

    Valkovic, Vladivoj

    2015-01-01

    Despite the often difficult and time-consuming effort of performing experiments with fast (14 MeV) neutrons, these neutrons can offer special insight into nucleus and other materials because of the absence of charge. 14 MeV Neutrons: Physics and Applications explores fast neutrons in basic science and applications to problems in medicine, the environment, and security.Drawing on his more than 50 years of experience working with 14 MeV neutrons, the author focuses on:Sources of 14 MeV neutrons, including laboratory size accelerators, small and sealed tube generators, well logging sealed tube ac

  14. Monte Carlo electron/photon transport

    A review of nonplasma coupled electron/photon transport using Monte Carlo method is presented. Remarks are mainly restricted to linerarized formalisms at electron energies from 1 keV to 1000 MeV. Applications involving pulse-height estimation, transport in external magnetic fields, and optical Cerenkov production are discussed to underscore the importance of this branch of computational physics. Advances in electron multigroup cross-section generation is reported, and its impact on future code development assessed. Progress toward the transformation of MCNP into a generalized neutral/charged-particle Monte Carlo code is described. 48 refs

  15. Semiconductor quantum optics with tailored photonic nanostructures

    This thesis describes detailed investigations of the effects of photonic nanostructures on the light emission properties of self-assembled InGaAs quantum dots. Nanoscale optical cavities and waveguides are employed to enhance the interaction between light and matter, i.e. photons and excitons, up to the point where optical non-linearities appear at the quantum (single photon) level. Such non-linearities are an essential component for the realization of hardware for photon based quantum computing since they can be used for the creation and detection of non-classical states of light and may open the way to new genres of quantum optoelectronic devices such as optical modulators and optical transistors. For single semiconductor quantum dots in photonic crystal nanocavities we investigate the coupling between excitonic transitions and the highly localized mode of the optical cavity. We explore the non-resonant coupling mechanisms which allow excitons to couple to the cavity mode, even when they are not spectrally in resonance. This effect is not observed for atomic cavity quantum electrodynamics experiments and its origin is traced to phonon-assisted scattering for small detunings (ΔE∝5 meV). For quantum dots in high-Q cavities we observe the coherent coupling between exciton and cavity mode in the strong coupling regime of light-matter interaction, probe the influence of pure dephasing on the coherent interaction at high excitation levels and high lattice temperatures, and examine the coupling of two spatially separated quantum dots via the exchange of real and virtual photons mediated by the cavity mode. Furthermore, we study the spontaneous emission properties of quantum dots in photonic crystal waveguide structures, estimate the fraction of all photons emitted into the propagating waveguide mode, and demonstrate the on-chip generation of single photon emission into the waveguide. The results obtained during the course of this thesis contribute significantly to

  16. (γ,n) reaction in nuclei of the 12<=A<=238 interval in the intermediate energy region (300 MeV-1000MeV)

    The absolute cross section of the 12C(γ,n)11C, 19F(γ,n)18F, 23Na(γ,n)22Na, 31P(γ,n)30P, 52Cr(γ,n)51Cr, 55Mn(γ,n)54Mn, 59Co(γ,n)58Co, 75As(γ,n)74As, 103Rh(γn)102Rh, 127I(γ,n)126I, 197Au(γ,n)196Au and 238U(γ,n)237U reactions were determined, experimentally, in the energy range from 300 MeV to 1000 MeV, using Bremsstrahlung photons. The measured cross sections were compared with results estimated by Monte Carlo Method applied to intranuclear cascades initiated by phothons. A functional dependence between the average value of (γ,n) absolute cross section and the mass number, were established. The (γ,n) absolute cross sections from simple relations, which transparencies of complexe nuclei for mesons and nucleons photo produced were also determined. (M.C.K.)

  17. Photonic Crystals Towards Nanoscale Photonic Devices

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis

    2005-01-01

    Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...

  18. Photonic Crystals Towards Nanoscale Photonic Devices

    Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique

    2008-01-01

    Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...

  19. High resolution (γ, n) experiments in light nuclei at Eγ ≅ 60 MeV

    The experiments was undertaken to establish the real photon reaction mechanism on light nuclei in the intermediate photon-energy region, Eγ ≅ 60 MeV. The shortage of high quality (γ, n) data was the main motivation for starting a systematic investigation of this reaction channel. In this work, 12C and 16O were examined. In the future, both heavier (40Ca) and lighter (4He) targets will be investigated. Two neutron detector arrays were built and tested. A state-of-the-art neutron spectrometer was constructed by combining these arrays with a high resolution (≅ 300 keV) photon tagger. The intrinsic time resolution of this spectrometer (≅ 800 ps) allowed an excellent neutron energy resolution to be achieved (≅ 1 MeV) with fairly short flight paths (≅ 6 m), thereby optimizing the geometrical efficiency (≅ 10 msr) of the apparatus. The excellent energy resolution of the spectrometer allowed individual states (or cluster of states) to be resolved. This resolution approaches that available for the (γ, p) reaction. For 12C and 16O the same states seen in the (γ, p) reaction were observed over an angular range from 30-115 degrees. The most important result, concerning the obtained absolute differential cross sections, is the striking similarity between the (γ, p) and (γ, n) reaction channels. This applies to both target nuclei for all populated states, independent of character (1h or 2h1p). A much detailed comparison is thus possible with these new data, providing greater constraints on the theoretical models. Further, access to more and better data will hopefully attract greater theoretical interest. The experiment was a collaboration between the Photonuclear research group at Lund University in Sweden and the Nuclear structure group from the University of Glasgow. The data were collected at MAX-lab in Lund, Sweden, during two run periods in November 1990 and February 1992. 96 refs, 105 figs, 28 tabs

  20. Valine radiolysis by MeV ions

    Da Silveira, Enio

    2016-07-01

    Valine, (CH3)2 CHCH (NH2) COOH, is a protein amino acid that has been identified in extraterrestrial environments and in the Murchison meteorite [1]. The knowledge of half-lives of small organic molecules under ionizing radiation is important for the setup of models describing the spread out of prebiotics across the Solar System or the Galaxy. We have investigated typical effects of MeV cosmic ray ions on prebiotic molecules in laboratory by impinging ions produced by the PUC-Rio Van de Graaff accelerator. Pure valine films, deposited by evaporation on KBr substrates, were irradiated by H ^{+}, He ^{+} and N ^{+} ion beams, from 0.5 to 1.5 MeV and up to a fluence of 10 ^{15} projectiles/cm ^{2}. The sample temperature was varied from 10 K to 300 K. The irradiation was interrupted several times for Mid-FTIR analysis of the sample. The main findings are: 1- The column density of the valine decreases exponentially with fluence. 2- In some cases, a second exponential appears in the beginning of irradiation; this feature has been attributed to sample compaction by the ion beam [2]. 3- Destruction cross sections of valine are in the 10 ^{-15} cm ^{2} range, while compaction cross sections are in the 10 ^{-14} cm ^{2} range. 4- Destruction cross section increases with the stopping power of the beam and also with the sample temperature. 5- Surprisingly, during the radiolysis of valine, just CO _{2} is seen by as a daughter molecule formed in the bulk. 6- After long beam fluence, also a CO peak appears in the infrared spectrum; this species is however interpreted as a fragment of the formed CO2 molecules. 7- Considering the flux ratio between laboratory experiments and actual galactic cosmic rays, half-life of valine is predicted for ISM conditions [3]. This work on pure valine is the first measurement of a series. New experiments are planned for determining cross sections of valine dissolved in H _{2}O or CO _{2}, inspired by the study performed for glycine [4]. [1] P

  1. Photon albedo for water, concrete, and iron at normal incidence, and dependence on the thickness of reflecting material

    Marković Vladimir M.; Krstić Dragana; Stevanović Nenad; Nikezić Dragoslav R.

    2013-01-01

    Total number and angular albedo were calculated for commonly used shielding materials, water, concrete, and iron, for photons with initial energies from 10 keV up to 10 MeV and normal incident angle. Influence of material thickness on total number albedo was also investigated. Double differential albedo was determined from simulation of photon transport through materials by using PENELOPE and MCNP software. Backscattered photons were scored and grouped in equal intervals of energy and a...

  2. Aspherical Photon and Anti-Photon Surfaces

    Gibbons, G W

    2016-01-01

    In this note we identify photon surfaces and anti-photon surfaces in some physically interesting spacetimes, which are not spherically symmetric. All of our examples solve physically reasonable field equations, including for some cases the vacuum Einstein equations, albeit they are not asymptotically flat. Our examples include the vacuum C-metric, the Melvin solution of Einstein-Maxwell theory and generalisations including dilaton fields. The (anti-)photon surfaces are not round spheres, and the lapse function is not always constant.

  3. Photon-photon scattering: a tutorial

    Liang, Yi; Czarnecki, Andrzej

    2011-01-01

    Long-established results for the low-energy photon-photon scattering, gamma gamma --> gamma gamma, have recently been questioned. We analyze that claim and demonstrate that it is inconsistent with experience. We demonstrate that the mistake originates from an erroneous manipulation of divergent integrals and discuss the connection with another recent claim about the Higgs decay into two photons. We show a simple way of correctly computing the low-energy gamma gamma scattering.

  4. Azimuthal Correlations in Photon-Photon Collisions

    Arteaga, N.; Carimalo, C.; Kessler, P.; Ong, S.; Panella, O.

    1995-01-01

    Using the general helicity formula for $\\gamma^* \\gamma^*$ collisions, we are showing that it should be possible to determine a number of independent ``structure functions'', i.e. linear combinations of elements of the two-photon helicity tensor, through azimuthal correlations in two-body or quasi two-body reactions induced by the photon-photon interaction, provided certain experimental conditions are satisfied. Numerical results of our computations are presented for some particular processes...

  5. Photon-Photon Interactions via Rydberg Blockade

    Fleischhauer, Michael; Pohl, Thomas; Gorshkov, Alexey Vyacheslavovich; Otterbach, Johannes; Lukin, Mikhail D.

    2011-01-01

    We develop the theory of light propagation under the conditions of electromagnetically induced transparency (EIT) in systems involving strongly interacting Rydberg states. Taking into account the quantum nature and the spatial propagation of light, we analyze interactions involving few-photon pulses. We demonstrate that this system can be used for the generation of nonclassical states of light including trains of single photons with an avoided volume between them, for implementing photon-phot...

  6. Photonic Eigenmodes in a Photonic Crystal Membrane

    E. Ya. Glushko; O. E. Glushko; L. A. Karachevtseva

    2012-01-01

    Photonic membranes are the most widely used kind of 2D photonic crystals in signal processing. Nevertheless, some important aspects of electromagnetic field behavior in membrane like photonic crystals (MPCs) need detail investigation. We develop the approach close to resonant coupling modes method which unites both external and intrinsic problems, in-plane and out-of-plane geometries, and resonator properties of MPC. The resonator standing modes are excited by an external source through the s...

  7. Photon statistics of intense entangled photon pulses

    Schlawin, F.; Mukamel, S

    2013-01-01

    Time- and frequency-gated two-photon counting is given by a four-time correlation function of the electric field. This reduces to two times with purely time gating. We calculate this function for entangled photon pulses generated by parametric down-conversion. At low intensity, the pulses consist of well-separated photon pairs, and crossover to squeezed light as the intensity is increased. This is illustrated by the two-photon absorption signal of a three-level model, which scales linearly fo...

  8. Measurement of energy and direction distribution of neutron and photon fluences in workplace fields

    Within the EU Project EVIDOS, a spectrometer with 24 silicon detectors mounted on the surface of a polyethylene sphere is used for the determination of the energy and direction distribution of neutrons and photons. It has been characterized with respect to neutron radiation with energies from thermal up to 15 MeV and to photon radiation with energies from 65 keV to 6 MeV. The first measurements described here were performed in the simulated workplace field, CANEL, at Cadarache, with the purpose of checking the instrument and the unfolding procedures. (authors)

  9. The Heavy Photon Search experiment at Jefferson Laboratory

    Celentano, Andrea [INFN-GENOVA

    2014-11-01

    The Heavy Photon Search experiment (HPS) at Jefferson Laboratory will search for a new U(1) massive gauge boson, or "heavy-photon", mediator of a new fundamental interaction, called "dark-force", that couples to ordinary photons through kinetic mixing. HPS has sensitivity in the mass range 20 MeV – 1 GeV and coupling epsilon2 between 10−5 and 10−10. The HPS experiment will look for the e+e− decay of the heavy photon, by resonance search and detached vertexing, in an electron beam fixed target experiment. HPS will use a compact forward spectrometer, which employs silicon microstrip detectors for vertexing and tracking, and a PbWO4 electromagnetic calorimeter for energy measurement and fast triggering.

  10. The Heavy Photon Search experiment at Jefferson Laboratory

    The Heavy Photon Search experiment (HPS) at Jefferson Laboratory will search for a new U(1) massive gauge boson, or heavy-photon, mediator of a new fundamental interaction, called dark-force, that couples to ordinary photons through kinetic mixing. HPS has sensitivity in the mass range 20 MeV – 1 GeV and coupling ε2 between 10−5 and 10−10. The HPS experiment will look for the e+e− decay of the heavy photon, by resonance search and detached vertexing, in an electron beam fixed target experiment. HPS will use a compact forward spectrometer, which employs silicon microstrip detectors for vertexing and tracking, and a PbWO4 electromagnetic calorimeter for energy measurement and fast triggering

  11. The Heavy Photon Search experiment at Jefferson Laboratory

    Celentano, Andrea

    2015-01-01

    The Heavy Photon Search experiment (HPS) at Jefferson Laboratory will search for a new $U(1)$ massive gauge boson, or "heavy-photon," mediator of a new fundamental interaction, called "dark-force," that couples to ordinary photons trough kinetic mixing. HPS has sensitivity in the mass range 20 MeV - 1 GeV and coupling $\\varepsilon^2$ between 10$^{-5}$ and 10$^{-10}$. The HPS experiment will search for the $e^+e^-$ decay of the heavy photon, by resonance search and detached vertexing, in an electron beam fixed target experiment. HPS will use a compact forward spectrometer, which employs silicon microstrip detectors for vertexing and tracking, and a PbWO$_4$ electromagnetic calorimeter for energy measurement and fast triggering.

  12. Characterization of gamma-ray detectors with tagged photons

    Schnorrenberger, Linda

    2012-07-01

    Photon detectors are used for various kinds of experiments in the field of nuclear physics. The response function of photon detectors on gamma rays is complex and needs to be considered during the analysis of experimental data. This thesis experimentally investigates such response functions for different detector types in a large energy range (2-20 MeV). The experiments described in this thesis were performed at the NEPTUN photon tagging facility, which provides a mono energetic photon source with tunable energy and intensity. As these were the first experiments to be performed at NEPTUN, within this study extensive development and commissioning of the setup also with respect to future campaigns were accomplished. The setup is shown to be well suited for the systematic study of detector response functions, while measurements of nuclear reactions need further improvements. (orig.)

  13. Energy response improvement for photon dosimetry using pulse analysis

    Zaki, Dizaji H.

    2016-02-01

    During the last few years, active personal dosimeters have been developed and have replaced passive personal dosimeters in some external monitoring systems, frequently using silicon diode detectors. Incident photons interact with the constituents of the diode detector and produce electrons. These photon-induced electrons deposit energy in the detector's sensitive region and contribute to the response of diode detectors. To achieve an appropriate photon dosimetry response, the detectors are usually covered by a metallic layer with an optimum thickness. The metallic cover acts as an energy compensating shield. In this paper, a software process is performed for energy compensation. Selective data sampling based on pulse height is used to determine the photon dose equivalent. This method is applied to improve the energy response in photon dosimetry. The detector design is optimized for the response function and determination of the photon dose equivalent. Photon personal dose equivalent is determined in the energy range of 0.3-6 MeV. The error values of the calculated data for this wide energy range and measured data for 133Ba, 137Cs, 60Co and 241Am-Be sources respectively are up to 20% and 15%. Fairly good agreement is seen between simulation and dose values obtained from our process and specifications from several photon sources.

  14. Aspects on the optimal photon beam energy for radiation therapy

    The selection of optimal photon beam energy is investigated both for realistic clinical bremsstrahlung beams and for monoenergetic photon beams. The photon energies covered in this investigation range from 60Co to bremsstrahlung and monoenergetic beams with maximum energies up to 50 MeV. One head and neck tumor and an advanced cervix tumor are investigated and the influence of beam direction is considered. It is shown that the use of optimized intensity modulated photon beams significantly reduces the need of beam energy selection. The most suitable single accelerator potential will generally be in the range 6-15 MV for both superficially located and deep-seated targets, provided intensity-modulated dose delivery is employed. It is also shown that a narrow penumbra region of a photon beam ideally should contain low-energy photons (≤4 MV), whereas the gross tumor volume, particularly when deep-seated targets are concerned, should be irradiated by high-energy photons. The regions where low photon energies are most beneficial are where organs at risk are laterally close to the target volume. The situation is completely changed when uniform or wedged beams are used. The selection of optimal beam energy then becomes a very important task in line with the experience from traditional treatment techniques. However, even with a large number of uniform beam portals, the treatment outcome is substantially lower than with a few optimized intensity-modulated beams. (orig.)

  15. The High Energy Emission of the Crab Nebula from 20 keV to 6 MeV with INTEGRAL

    Jourdain, E

    2009-01-01

    The SPI spectrometer aboard the INTEGRAL mission observes regularly the Crab Nebula since 2003. We report on observations distributed over 5.5 years and investigate the variability of the intensity and spectral shape of this remarkable source in the hard X-rays domain up to a few MeV. While single power law models give a good description in the X-ray domain (mean photon index ~ 2.05) and MeV domain (photon index ~ 2.23), crucial information are contained in the evolution of the slope with energy between these two values. This study has been carried out trough individual observations and long duration (~ 400 ks) averaged spectra. The stability of the emission is remarkable and excludes a single power law model. The slopes measured below and above 100 keV agree perfectly with the last values reported in the X-ray and MeV regions respectively, but without indication of a localized break point. This suggests a gradual softening in the emission around 100 keV and thus a continuous evolution rather than an actual c...

  16. Quantum Computing using Photons

    Elhalawany, Ahmed; Leuenberger, Michael

    2013-03-01

    In this work, we propose a theoretical model of two-quantum bit gates for quantum computation using the polarization states of two photons in a microcavity. By letting the two photons interact non-resonantly with four quantum dots inside the cavity, we obtain an effective photon-photon interaction which we exploit for the implementation of an universal XOR gate. The two-photon Hamiltonian is written in terms of the photons' total angular momentum operators and their states are written using the Schwinger representation of the total angular momentum.

  17. 10 MeV Medical Cyclotron Prototype Beam Commissioning

    GUAN; Feng-ping; GE; Tao; YIN; Zhi-guo; SONG; Guo-fang; ZHANG; Tian-jue; JI; Bin; LI; Peng-zhan; CAO; Lei; HOU; Shi-gang; LIU; Geng-shou; WANG; Feng; LEI; Yu; WU; Long-cheng; WEN; Li-peng; LI; Zhen-guo; CUI; Tao; JIA; Xian-lu; YAO; Hong-juan; PAN; Gao-feng; ZHANG; Su-ping; CAI; Hong-ru; XIE; Huai-dong

    2012-01-01

    <正>A 10 MeV medical cyclotron prototype for the production of short-lived isotopes has been developed independently at CIAE with a time span of 2 years. On the inner target, 8 hours stability test has been finished. The extraction beam is 10 MeV with a beam intensity of 100 μA.

  18. Preliminary Report on the Evaluation of an Electron-Positron Collider as a source of Monoenergetic Photons

    Fast, James E.; Campbell, Luke W.

    2009-11-30

    Abstract Active interrogation methods are being investigated to detect shielded special nuclear material (SNM). These approaches utilize either neutron or photon beams to excite the SNM in concert with either neutron or gamma ray detectors to observe the stimulated emissions. The two primary methodologies with photon beams are photofission and nuclear resonance florescence (NRF). Photofission requires photons energies of 7-10 MeV while NRF requires photon energies around 2 MeV. For both techniques, photons that are not in the appropriate energy band, e.g. the low energy tail of a Bremsstrahlung photon beam, contribute unwanted additional radiation dose to cargo. Typically less than 10% of the photons are in the usable energy band. The additional photon production generates a commensurate amount of additional radiation dose in the source and target areas, impacting shielding requirements and/or dose to operators and equipment and at the expense of a similar increase in power consumption. Hence it is highly desirable to produce narrow energy (“monoenergetic”) photon beams with tunable energy in the range of ~2-20 MeV.

  19. Preoperative irradiation in carcinoma of the pancreas. [/sup 60/Co or 46 MeV photons

    Pilepich, M.V. (Washington Univ., St. Louis, MO); Miller, H.H.

    1980-11-01

    Seventeen patients with carcinoma confined to the pancreas and the peripancreatic area received preoperative radiation therapy in an attempt to increase the resectability rate and to reduce the incidence of recurrence. The tumors were considered either unresectable or of borderline resectability. The radiation dose ranged between 4000 to 5000 rads, the majority of patients (75%) receiving 4400 to 4600 rads in 4 1/2 to 5 weeks. After a period averaging six weeks the patients were reevaluated for surgery. Eleven patients were explored and six underwent radical resection. Two patients remained disease free after five years. Pancreatic resection is feasible following a course of preoperative radiotherpy to a moderately high dose. It is suggested that the response of the primary tumor to radiotherapy be used as a criterion for selecting patients for reexploration and resection.

  20. The experiment 787 high efficiency photon veto detector in the 20 - 300 MEV range

    Experiment E787 is searching for the rare decay K → πνν at the Brookhaven Alternating Gradient Synchrotron (AGS). To suppress the background from the dominant K → ππo branch, a fast lead scintillator sandwich veto assembly system was used. An inefficiency level of ∼ 1 x 10-6 has been achieved for detecting πo. The limitations are in part geometrical in part due to photonuclear interactions. Our present understanding of these limitations will be presented together with our upgrading plans using pure CSI crystals. (author). 7 refs., 4 figs

  1. Controllable photon source

    Oszetzky, Dániel; Nagy, Attila; Czitrovszky, Aladár

    2006-10-01

    We have developed our pervious experimental setup using correlated photon pairs (to the calibration of photo detectors) to realize a controllable photon source. For the generation of such photon pairs we use the non-linear process of parametric down conversion. When a photon of the pump beam is incident to a nonlinear crystal with phase matching condition, a pair of photons (signal and idler) is created at the same time with certain probability. We detect the photons in the signal beam with a single photon counting module (SPCM), while delaying those in the idler beam. Recently we have developed a fast electronic unit to control an optical shutter (a Pockels cell) placed to the optical output of the idler beam. When we detect a signal photon with the controlling electronic unit we are also able to open or close the fast optical shutter. Thus we can control which idler photons can propagate through the Pockels cell. So with this photon source we are able to program the number of photons in a certain time window. This controllable photon source that is able to generate a known number of photons with specified wavelength, direction, and polarization could be useful for applications in high-accuracy optical characterisation of photometric devices at the ultra-low intensities. This light source can also serve as a standard in testing of optical image intensifiers, night vision devices, and in the accurate measurement of spectral distribution of transmission and absorption in optical materials.

  2. Monochromatic and identifiable photons used in photonuclear research

    A general overview is given of the most common experimental procedures for the production and utilisation of monochromatic and (or) identifiable photon probes actually operational in 1979. Their basic characteristics, merits and drawbacks, together with their respective major domains of experimental physics to which they are usually applied, are also investigated. Methods for producing such monochromatic and (or) identifiable photon probes, with a continuously variable energy from a few MeV up till about 180 GeV, are treated in some detail. Some of the most promising future trends in the ulterior development of such electromagnetic probes are also mentioned

  3. Two-Photon Total Annihilation of Molecular Positronium

    Pérez-Ríos, Jesús; Greene, Chris H

    2014-01-01

    The rate for complete two-photon annihilation of molecular positronium Ps$_{2}$ is reported. This decay channel involves a four-body collision among the fermions forming Ps$_{2}$, and two photons of 1.022 MeV, each, as the final state. The quantum electrodynamics result for the rate of this process is found to be $\\Gamma_{Ps_{2} \\rightarrow \\gamma\\gamma}$ = 9.0 $\\times 10^{-12}$ s$^{-1}$. This decay channel completes the most comprehensive decay chart for Ps$_{2}$ up to date.

  4. Photon interaction data for ENDF/B-VI

    The ENDF/B-VI photon interaction library includes data for the elements hydrogen (Z=1) through fermium (Z=100) over the energy range 10 eV to 100 MeV. This library contains data to meet the needs of traditional photon transport methods. However, this library also contains data that can be used to perform much more detailed transport calculations. This paper describes the contents of this library and how it can be used for both traditional and more detailed transport calculations

  5. Axion-like particle searches with sub-THz photons

    Capparelli, L; Ferretti, J; Giazotto, F; Polosa, A D; Spagnolo, P

    2015-01-01

    We propose a variation, based on very low energy and extremely intense photon sources, on the well established technique of Light-Shining-through-Wall (LSW) experiments for axion-like particle searches. With radiation sources at 30 GHz, we compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude, for masses m_a <~ 0.01~meV. This could motivate research and development programs on dedicated single-photon sub-THz detectors.

  6. Axion-like particle searches with sub-THz photons

    Capparelli, L. M.; Cavoto, G.; Ferretti, J.; Giazotto, F.; Polosa, A. D.; Spagnolo, P.

    2016-06-01

    We propose a variation, based on very low energy and extremely intense photon sources, on the well established technique of Light-Shining-through-Wall (LSW) experiments for axion-like particle searches. With radiation sources at 30 GHz, we compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude, for masses ma ≲ 0.01 meV. This could motivate research and development programs on dedicated single-photon sub-THz detectors.

  7. Low-power communication with a photonic heat pump.

    Huang, Duanni; Santhanam, Parthiban; Ram, Rajeev J

    2014-12-15

    An optical communication channel is constructed using a heated thermo-electrically pumped, high efficiency infrared light-emitting diode (LED). In these devices, electro-luminescent cooling is observed, resulting in greater than unity (> 100%) efficiency in converting electrical power to optical power. The average amount of electrical energy required to generate a photon (4.3 meV) is much less than the optical energy in that photon (520 meV). Such a light source can serve as a test-bed for fundamental studies of energy-efficient bosonic communication channels. In this low energy consumption mode, we demonstrate data transmission at 3 kilobits per second (kbps) with only 120 picowatts of input electric power. Although the channel employs a mid-infrared source with limited quantum efficiency, a binary digit can be communicated using 40 femtojoules with a bit error rate of 3 x 10-3. PMID:25607478

  8. Photon and photoneutron spectra produced in radiotherapy Linacs

    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 10-6 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)

  9. Photon and photoneutron spectra produced in radiotherapy Linacs

    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)

  10. Nuclear photon science with inverse-Compton scattering

    Recent developments of the synchroton radiation facilities and intense lasers are now guiding us to a new research frontier with probes of a high energy GeV photon beam and an intense and short pulse MeV γ-ray beam. New directions of the science developments with photo-nuclear reactions are discussed. The inverse Compton γ -ray has two good advantages for searching for a microscopic quantum world; they are 1) good emmitance and 2) high linear and circular polarizations. With these advantages, photon beams in the energy range from MeV to GeV are used for studying hadron structure, nuclear structure, astrophysics, materials science, as well as for applying medical science. (author)