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Your search keyword '"Compton scattering"' showing total 18 results
18 results on '"Compton scattering"'

1. Neutron activation analysis using gamma-gamma coincidence to eliminate spectral interferences.

Author

Martinez, Francis J. and Landsberger, Sheldon

Subjects
*NUCLEAR activation analysis, *COINCIDENCE, *COMPTON scattering, *GAMMA rays, *RADIOISOTOPES, *GAMMA ray spectrometry
Abstract

The use of neutron activation analysis (NAA) sometimes has limitations with the identification of specific gamma ray peaks due to spectral interferences. The implementation of gamma-gamma coincidence techniques using the XIA Pixie-16 system has demonstrated the ability reduce many of these challenges. Experiments were performed on two different NIST reference materials using gamma-gamma coincidence techniques to identify long-lived radionuclides that are often difficult to evaluate due to various spectral interferences. The experiments have shown that utilizing gamma-gamma coincidence with the XIA Pixie-16 system for 177mLu, 124Sb, 160 Tb, 175Yb, and 153Sm can eliminate spectral interferences and high backgrounds due to Compton scattering. [ABSTRACT FROM AUTHOR]

Published
2022
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2. Inter-crystal scattering recovery of light-sharing PET detectors using convolutional neural networks.

Author

Lee, Seungeun and Lee, Jae Sung

Subjects
*CONVOLUTIONAL neural networks, *COINCIDENCE, *MONTE Carlo method, *SPATIAL resolution, *LIGHT scattering, *POSITRON emission tomography, *COMPTON scattering, *RADIOACTIVE tracers
Abstract

Inter-crystal scattering (ICS) is a type of Compton scattering of photons from one crystal to adjacent crystals and causes inaccurate assignment of the annihilation photon interaction position in positron emission tomography (PET). Because ICS frequently occurs in highly light-shared PET detectors, its recovery is crucial for the spatial resolution improvement. In this study, we propose two different convolutional neural networks (CNNs) for ICS recovery, exploiting the good pattern recognition ability of CNN techniques. Using the signal distribution of a photosensor array as input, one network estimates the energy deposition in each crystal (ICS-eNet) and another network chooses the first-interacted crystal (ICS-cNet). We performed GATE Monte Carlo simulations with optical photon tracking to test PET detectors comprising different crystal arrays (8 × 8 to 21 × 21) with lengths of 20 mm and the same photosensor array (3 mm 8 × 8 array) covering an area of 25.8 × 25.8 mm2. For each detector design, we trained ICS-eNet and ICS-cNet and evaluated their respective performance. ICS-eNet accurately identified whether the events were ICS (accuracy > 90%) and selected interacted crystals (accuracy > 60%) with appropriate energy estimation performance (R2 > 0.7) in the 8 × 8, 12 × 12, and 16 × 16 arrays. ICS-cNet also exhibited satisfactory performance, which was less dependent on the crystal-to-sensor ratio, with an accuracy enhancement that exceeds 10% in selecting the first-interacted crystal and a reduction in error distances compared when no recovery was applied. Both ICS-eNet and ICS-cNet exhibited consistent performances under various optical property settings of the crystals. For spatial resolution measurements in PET rings, both networks achieved significant enhancements particularly for highly pixelated arrays. We also discuss approaches for training the networks in an actual experimental setup. This proof-of-concept study demonstrated the feasibility of CNNs for ICS recovery in various light-sharing designs to efficiently improve the spatial resolution of PET in various applications. [ABSTRACT FROM AUTHOR]

Published
2021
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3. Cs2ZrCl6 scintillation properties studied using γ-ray spectroscopy and Compton coincidence technique.

Author

Swiderski, L., Brylew, K., Janiak, L., Mianowska, Z., Moszyński, M., Mykhaylyk, V., Nagorny, S.S., Nahorna, V.V., and Wang, P.

Subjects
*COINCIDENCE, *PHOTOMULTIPLIERS, *ENERGY function, *COMPTON scattering, *SPECIAL effects in lighting, *PHOTONS
Abstract

The scintillation properties of cesium-zirconium hexachloride (Cs 2 ZrCl 6) were investigated by γ-ray spectrometry and the Compton Coincidence Technique. The tested cylindrical sample had 20 mm diameter and 12 mm height. The crystal shows a high light output of 40 900 photons per MeV as measured by a spectroscopy type photomultiplier with 20 μs pulse integration time under γ-ray excitation at room temperature. A small deviation from linear response as a function of energy deposited in γ-ray absorption or Compton scattering processes, combined with a high light yield, results in good energy resolution equal to 4.3 % at 662 keV and 2.3 % at 2.6 MeV. Due to long lasting scintillation decay the sample properties were studied at different shaping time constants in an analogue spectroscopy chain or using different integration time gates when employing a digital analyzer. [ABSTRACT FROM AUTHOR]

Published
2023
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4. Dynamics of Nuclear Cascades in the Photoproduction of Light Neutral Mesons.

Author

Nedorezov, V. G. and Turinge, A. A.

Subjects
*COMPTON scattering, *MESONS, *PARTICLE analysis, *PIONS, *PARTICLES (Nuclear physics), *PHOTONS, *COINCIDENCE
Abstract

New experimental data on the multifragmentation of carbon nuclei that is initiated by the photoproduction of neutral pions and eta mesons are discussed. The novelty is associated with the exclusive character of the processes being studied, in which case a determination of partial meson-photoproduction reactions is followed by an analysis of complementary particles for coincidence. The experiment being discussed was performed by the GRAAL (GRenoble Accelerateur Anneau Laser) Collaboration in a beam of 500- to 1500-MeV Compton photons. The possibility of performing new experiments within the BGO-OD Collaboration (Bonn, Germany) is considered. A new method for studying the interaction of short-lived mesons with nuclei on the basis of detecting cascade recoil nucleons is proposed. [ABSTRACT FROM AUTHOR]

Published
2020
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5. A New Method and Apparatus for High-Resolution γ-Radiographic Introscopy of Bulk Heavy-Metal Products and Blanks. First Application Results.

Author

Gorbunov, M. A., Dudin, S. V., Ignatyev, O. V., Kupchinskaya, E. A., Kupchinsky, A. V., Morozov, S. G., and Pulin, A. A.

Subjects
*COMPTON scattering, *SCINTILLATION counters, *PHOTOMULTIPLIERS, *DETECTORS, *COINCIDENCE circuits, *COINCIDENCE, *MANUFACTURED products
Abstract

A -introscopy method and an installation using "electronic focusing" of -quanta transmitted through the studied object are proposed. The apparatus contains a powerful 60Co-source; a device for positioning the studied object; and a measuring facility, including a thin scintillation coordinate detector-scatterer with 64 silicon photomultipliers (SiPMs) and digital detector pulse processors (PDPs), a total absorption scintillation detector with analog-digital PDP, a unit for coincidence and energy event selection and on-line coordinate calculation, and a communication interface to a PC. The spatial resolution achieved for thick objects is 400 μm. The theoretical limit is μm. [ABSTRACT FROM AUTHOR]

Published
2019
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6. A Monte Carlo simulation method for polarized gamma-ray nuclear resonance fluorescence.

Author

Chi, Zhijun, Zhang, Hongze, Lin, Jin, Zhang, Xuanqi, Ding, Hao, Zhang, Zhi, Du, Yingchao, Huang, Wenhui, and Tang, Chuanxiang

Subjects
*INVERSE Compton scattering, *NUCLEAR research, *GAMMA-ray scattering, *COMPTON scattering, *GAMMA rays, *INVERSE scattering transform, *COINCIDENCE, *MONTE Carlo method
Abstract

With the rapid development of inverse Compton scattering gamma-ray sources, highly polarized gamma rays play a significant role in fundamental nuclear physics research based on nuclear resonance fluorescence (NRF). To meet the requirements of those applications, especially for guiding experiments and optimizing detection systems, a Monte Carlo simulation method for linearly polarized gamma-ray NRF is developed and implemented in the general-purpose toolkit Geant4. To validate the effectiveness of this method, simulations are compared with both theoretical and experimental results and are found to agree well with both. As a typical application of the linearly polarized gamma-ray NRF technique, a gamma-ray polarization measurement method is proposed in the energy region from hundreds of keV to several MeV, and its feasibility is analyzed based on the developed simulation method. Compared with the conventional Compton scattering method, the analyzing power of the NRF method is improved about 3.7-fold by using a 28 Si target, and reaches a value of more than 0.99 at a reasonable data acquisition time. [ABSTRACT FROM AUTHOR]

Published
2023
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7. Geant4 simulation study on detection efficiencies of the Compton suppression system at the HL-2A tokamak.

Author

Zhang, Jie, Zhang, Pengfei, Zhang, Yipo, Yang, Jinwei, Yuan, Guoliang, Song, Xianying, Li, Xu, and Zhou, Yan

Subjects
*COMPTON scattering, *FUSION reactors, *MOLECULAR spectra, *INFORMATION storage & retrieval systems, *GERMANIUM, *BISMUTH, *COINCIDENCE
Abstract

A Compton suppression system (CSS), which plays an important role in γ-ray diagnostics, has been developed to acquire the γ-ray emission spectra generated in the HL-2A tokamak plasma. It takes advantages of the anti-coincidence method of two branches of γ-ray signals, one is from a high purity germanium (HPGe) detector, and the other from several bismuth germinate (BGO) detectors, to output the suppressed spectra. In the present paper, a Geant4 simulation, together with its subsequent data processing which took accidental coincidences into account, was performed to study the detection efficiencies of the CSS for γ-rays with energies between 0.2 and 13 MeV. Calculation results showed that there were small detection efficiency differences between the unsuppressed and suppressed spectra when HPGe count rates were smaller than 105 cps, and the area ratios of additional peaks to their corresponding full energy peaks were not associated with HPGe count rates. Based on the calculation results, the empirical formulas of detection efficiencies of the CSS were put forward. Finally, after the experimental verification of the empirical formulas, a suppressed γ-ray spectrum acquired by the CSS during 2018 HL-2A experiment campaign was unfolded using the detection efficiencies. This work makes it possible for the analyses of the γ-ray emission spectra generated from the HL-2A tokamak. • The detection efficiencies of the Compton suppression system at the HL-2A tokamak have been calculated using Geant4. • The detection efficiency calculations with Geant4 have taken accidental coincidences into account. • The empirical formulas of detection efficiencies of the Compton suppression system have been put forward. [ABSTRACT FROM AUTHOR]

Published
2019
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8. Investigation of GaGG:Ce with TOFPET2 ASIC Readout for Applications in Gamma Imaging Systems

Author

Mihael Makek, Damir Bosnar, Luka Pavelić, and Ana Marija Kožuljević

Subjects
compton imaging, Materials science, positron emission tomography, General Chemical Engineering, Scintillator, 01 natural sciences, Coincidence, 030218 nuclear medicine & medical imaging, Inorganic Chemistry, Crystal, GaGG, 03 medical and health sciences, 0302 clinical medicine, Silicon photomultiplier, 0103 physical sciences, lcsh:QD901-999, General Materials Science, silikonski fotomultiplikator, pozitronska emisijska tomografija, Compton-sko oslikavanje, polarizacija gama-zraka, TOFPET2, 010308 nuclear & particles physics, business.industry, Resolution (electron density), Detector, Compton scattering, Condensed Matter Physics, NATURAL SCIENCES. Physics, gamma polarization, PRIRODNE ZNANOSTI. Fizika, Optoelectronics, lcsh:Crystallography, business, silicon photomultiplier, Voltage
Abstract

We investigated two detector modules, each consisting of a 8 &times, 8 matrix of GaGG:Ce crystals with a crystal size of 3 &times, 3 &times, 20 mm3 and a 3.2 mm pitch. The light is collected by a 8 &times, 8 silicon photomultiplier array, with one silicon photomultiplier matching one crystal. The signals are read out and processed using the TOFPET2 ASIC. Performed laboratory tests of the detectors were performed using a 22Na source, where energy and coincidence time resolution with different optical coupling were examined between the crystals and silicon photomultipliers, as well as under various operating voltages. The mean energy resolution of 9.8&plusmn, 0.6% at 511 keV was observed and it was shown that the coincidence time resolution of 384&plusmn, 33 ps could be achieved. The results reassure that the GaGG scintillator is a very promising candidate for the development of imaging systems, in particular, ones utilizing Compton scattering where the energy resolution plays a critical role and a moderate timing performance is acceptable.

Published
2020

9. Scintillator Pixel Detectors for Measurement of Compton Scattering

Author

Damir Bosnar, Luka Pavelić, and Mihael Makek

Subjects
positron emission tomography, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, scintillation detector, Scintillator, 01 natural sciences, Compton camera, Compton scattering, silicon photomultiplier, medical applications, Coincidence, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Silicon photomultiplier, Optics, 0103 physical sciences, Physics, Scintillation, Pixel, 010308 nuclear & particles physics, business.industry, Detector, Gamma ray, Condensed Matter Physics, lcsh:QC1-999, NATURAL SCIENCES. Physics, Electronic, Optical and Magnetic Materials, PRIRODNE ZNANOSTI. Fizika, Computer Science::Programming Languages, business, lcsh:Physics
Abstract

The Compton scattering of gamma rays is commonly detected using two detector layers, the first for detection of the recoil electron and the second for the scattered gamma. We have assembled detector modules consisting of scintillation pixels, which are able to detect and reconstruct the Compton scattering of gammas with only one readout layer. This substantially reduces the number of electronic channels and opens the possibility to construct cost-efficient Compton scattering detectors for various applications such as medical imaging, environment monitoring, or fundamental research. A module consists of a 4 &times, 4 matrix of lutetium fine silicate scintillators and is read out by a matching silicon photomultiplier array. Two modules have been tested with a 22 Na source in coincidence mode, and the performance in the detection of 511 keV gamma Compton scattering has been evaluated. The results show that Compton events can be clearly distinguished with a mean energy resolution of 12.2% &plusmn, 0.7% in a module and a coincidence time resolution of 0 . 56 &plusmn, 0 . 02 ns between the two modules.

Published
2019

10. Double photon emission coincidence imaging with GAGG-SiPM Compton camera.

Author

Uenomachi, Mizuki, Mizumachi, Yuki, Yoshihara, Yuri, Takahashi, Hiroyuki, Shimazoe, Kenji, Yabu, Goro, Yoneda, Hiroki, Watanabe, Shin, Takeda, Shin'ichiro, Orita, Tadashi, Takahashi, Tadayuki, Moriyama, Fumiki, and Sugawara, Hirotaka

Subjects
*RADIOISOTOPES, *COINCIDENCE circuits, *COMPTON scattering, *COINCIDENCE, *CAMERAS, *POSITRON emission tomography, *SCINTILLATORS
Abstract

Compton imaging is a promising gamma-ray imaging method based on the Compton scattering kinematics due to high Compton scattering probability for sub-MeV to MeV gamma-rays. A conventional Compton camera has a disadvantage of low signal-to-background ratio (SBR), which is caused by drawing of multiple Compton cones. A method to solve this fundamental problem is the double-photon emission computed tomography (DPECT), which uses the coincidence detection for cascade gamma-rays and significantly increases the SBR using intersections of two Compton cones. In this study, we demonstrated the DPECT method by using 134Cs radio isotope, which is one of important radioisotopes for the imaging of fuel debris, with two Ce:Gd 3 (Al,Ga) 5 O 12 (GAGG) scintillator Compton cameras. [ABSTRACT FROM AUTHOR]

Published
2020
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11. Performance testing of a Compton suppressed coincidence measurements using the Advanced Radionuclide Gamma-spectrOmeter.

Author

Davies, A.V., Burnett, J.L., and Britton, R.

Subjects
*RADIOISOTOPES, *COINCIDENCE, *GERMANIUM detectors, *SODIUM iodide, *NEUTRON radiography, *MAGNITUDE (Mathematics), *GAMMA ray spectrometry, *NEUTRON spectroscopy, *COMPTON scattering
Abstract

A Compton-suppressed multidimensional gamma-spectrometer is being developed within the Shallow Underground Laboratory at Pacific Northwest National Laboratory (PNNL, USA). This Advanced Radionuclide Gamma-spectrOmeter system consists of two Broad Energy Germanium detectors, surrounded by a 12-detector sodium iodide Compton suppression shield, situated inside a low-background lead and copper shield, fitted with a cosmic veto background reduction system. The detector has advanced functionality, including operation in single or combined detector mode, coincidence mode and Compton suppressed coincidence mode. Performance testing experiments measuring a neutron irradiated natural uranium sample, have demonstrated order of magnitude improvements in gamma detection sensitivity compared to conventional gamma-spectrometry techniques. Importantly this research demonstrates the feasibility of processing and analysing high-multiplicity datasets and the potential for high-detection sensitivity radionuclide measurements. [ABSTRACT FROM AUTHOR]

Published
2020
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12. In-beam spectroscopic study of 63Zn.

Author

Ghosh, U. S., Rai, S., Mukherjee, B., Biswas, A., Mondal, A. K., Mandal, K., Chakraborty, A., Chakraborty, S., Mukherjee, G., Sharma, A., Bala, I., Muralithar, S., and Singh, R. P.

Subjects
*COMPTON scattering, *HEAVY ion fusion reactions, *EXCITED states, *COINCIDENCE, *PARITY (Physics)
Abstract

Investigation on the excited states of 63Zn was done through in-beam γ-ray spectroscopic techniques using the 52Cr(18O,α3n) fusion-evaporation reaction at a beam energy of 72.5 MeV. Detection of the emitted γ rays from the excited nuclei was performed in the coincidence mode using 14 Compton suppressed Ge clover detectors of the Indian National Gamma Array. Based on the γ-γ coincidence data, 13 new transitions have been placed in the level scheme following their coincidence relationship and intensity balance. Spin and parity assignments of the excited levels have been carried out by extracting the directional correlation from oriented states ratio and polarization asymmetry values of the emitted γ rays. Shell model calculations have been performed in the f5/2pg9/2 model space with a 56Ni core using the jj44bpn interaction, to interpret the observed excited states of the nucleus. A reasonable agreement is found between the experimental findings and the shell-model calculations. In order to understand the evolution of a collective shape built on the 9/2+ (1704 keV) state, we have performed total Routhian surface calculations with a 1g9/2 quasineutron and found reasonable agreement. [ABSTRACT FROM AUTHOR]

Published
2019
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13. A DOI-Dependent Extended Energy Window Method to Control Balance of Scatter and True Events

Author

Naoko Inadama, Eiji Yoshida, Keishi Kitamura, Kengo Shibuya, Tomoyuki Hasegawa, Taiga Yamaya, Hideo Murayama, Fumihiko Nishikido, and Chihfung Lam

Subjects
Physics, Nuclear and High Energy Physics, Scanner, business.industry, Image quality, Detector, Physics::Medical Physics, Compton scattering, Photoelectric effect, Coincidence, Optics, Nuclear Energy and Engineering, Electromagnetic shielding, Electrical and Electronic Engineering, business, Sensitivity (electronics)
Abstract

In a conventional PET scanner, coincidence events are limited by the energy window for detection of photoelectric events. In contrast, Compton scatter events occur both in a patient and in detector crystals. Scatter events within the patient cause scatter coincidences, but scatter events within crystals have useful information for an activity distribution. The PET scanner with an extended energy window has higher sensitivity but higher scatter fraction than the PET scanner with a default energy window. In this work, we develop a scatter reduction method using a depth-of-interaction (DOI) detector. The DOI detector can make an upper layer act as an absorber of patient scatter, thus shielding a lower layer. Therefore, Compton scatter events with an interaction at the lower layer mainly have more crystal scatter events than patient scatter events. Our method proposes a different energy window for each layer. The energy window of the upper layer is limited to the region of photopeak events, the same as done for the conventional PET scanner. The energy window of the lower layer is extended to the region of crystal scatter events and photopeak events. We tested our proposed technique for a whole-body PET scanner using GATE simulations. Simulation results show the DOI-PET scanner can provide more true events while keeping a low scatter fraction using our scatter reduction method. We conclude this method is promising for obtaining high image quality using DOI information and energy information.

Published
2008

14. New setup for the characterisation of the AGATA detectors

Author

F. Le Blanc, S. Leboutelier, D. Linget, P. Pariset, B. Travers, A. Korichi, T.M.H. Ha, N. Karkour, X. Grave, P. Desesquelles, N. Dosme, E. Legay, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), CSNSM SNO, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire d'Orsay (IPNO), CSNSM INFOR, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and CSNSM ELEC

Subjects
Nuclear and High Energy Physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Tracking (particle physics), 01 natural sciences, Coincidence, Collimated light, TOHR setup, PSA, Optics, 0103 physical sciences, Digital acquisition, Scanning, 010306 general physics, Instrumentation, Digital signal processing, Physics, 010308 nuclear & particles physics, business.industry, Detector, Compton scattering, HPGe segmented detectors, γ-Ray tracking, Semiconductor detector, AGATA, business
Abstract

A crucial step in the process of γ - ray tracking is related to the location of the interaction points of all the γ - rays within the AGATA (Advanced GAmma Tracking Array) segmented detectors. This requires a full understanding of the sensitivity of each highly segmented high-purity germanium (HPGe) detectors via the characterisation of the 2D and 3D position response. In this paper, we describe the experimental scanning setup that we developed at Orsay for the AGATA detectors. A collimated 137Cs source on an automated x–y positioning table was used for the front face scanning of the AGATA symmetric prototype detector. The 3D scanning measurement is performed using coincidence techniques based on γ - ray Compton scattering from the AGATA detector into an ancillary coupled detector. In our setup, TOHR (high resolution tomograph developed for small animal imaging) is used as an ancillary detector. The data is collected using TIGRESS cards for digital signal processing. The data flow, readout and storage is NARVAL as used for the full AGATA project. The analysis of the collected data and the obtained results is shown to illustrate our device performances.

Published
2012

15. A new SNR with TeV shell-type morphology: HESS J1731-347

Author

HESS Collaboration, Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balzer, A., Barnacka, A., de Almeida, U. Barres, Bazer-Bachi, A. R., Becherini, Y., Becker, J., Behera, B., Bernl��hr, K., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Borrel, V., Brucker, J., Brun, F., Brun, P., Bulik, T., B��sching, I., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Charbonnier, A., Chaves, R. C. G., Cheesebrough, A., Chounet, L. -M., Clapson, A. C., Coignet, G., Conrad, J., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., Dickinson, H. J., Djannati-Ata��, A., Domainko, W., Drury, L. O'C., Dubois, F., Dubus, G., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fiasson, A., Fontaine, G., F��rster, A., F����ling, M., Gallant, Y. A., Gast, H., G��rard, L., Gerbig, D., Giebels, B., Glicenstein, J. F., Gl��ck, B., Goret, P., G��ring, D., H��ffner, S., Hague, J. D., Hampf, D., Hauser, M., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hinton, J. A., Hoffmann, A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., de Jager, O. C., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzynski, K., Katz, U., Kaufmann, S., Keogh, D., Khangulyan, D., Kh��lifi, B., Klochkov, D., Kluzniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Laffon, H., Lamanna, G., Lennarz, D., L��hse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, D., Maxted, N., McComb, T. J. L., Medina, M. C., M��hault, J., Moderski, R., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nekrassov, D., Nguyen, N., Nicholas, B., Niemiec, J., Nolan, S. J., Ohm, S., Olive, J-P., Wilhelmi, E. de O��a, Opitz, B., Ostrowski, M., Panter, M., Arribas, M. Paz, Pedaletti, G., Pelletier, G., Petrucci, P. -O., Pita, S., P��hlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Rayner, S. M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Ruppel, J., Ryde, F., Sahakian, V., Santangelo, A., Schlickeiser, R., Sch��ck, F. M., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sikora, M., Skilton, J. L., Sol, H., Spengle, G., Stawarz, L., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tibolla3, O., Tluczykont, M., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Vialle, J. P., Viana, A., Vincent, P., Vivier, M., V��lk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., Wierzcholska, A., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., Zechlin, H. -S., Laboratoire Univers et Particules de Montpellier (LUPM), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), APC - Astrophysique des Hautes Energies (APC - AHE), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), HESS, Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'Annecy de Physique des Particules (LAPP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)

Subjects
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Electron, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Coincidence, Pion, cosmic rays, 0103 physical sciences, Angular resolution, High Energy Stereoscopic System, Supernova remnant, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, supernova remnants [ISM], [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Compton scattering, Astronomy and Astrophysics, Cherenkov Telescope Array, Space and Planetary Science, astroparticle physics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The recent discovery of the radio shell-type supernova remnant (SNR), G353.6-0.7, in spatial coincidence with the unidentified TeV source HESS J1731-347 has motivated further observations of the source with the High Energy Stereoscopic System (H.E.S.S.) Cherenkov telescope array to test a possible association of the gamma-ray emission with the SNR. With a total of 59 hours of observation, representing about four times the initial exposure available in the discovery paper of HESS J1731-347, the gamma-ray morphology is investigated and compared with the radio morphology. An estimate of the distance is derived by comparing the interstellar absorption derived from X-rays and the one obtained from 12CO and HI observations. The deeper gamma-ray observation of the source has revealed a large shell-type structure with similar position and extension (r~0.25{\deg}) as the radio SNR, thus confirming their association. By accounting for the H.E.S.S. angular resolution and projection effects within a simple shell model, the radial profile is compatible with a thin, spatially unresolved, rim. Together with RX J1713.7-3946, RX J0852.0-4622 and SN 1006, HESS J1731-347 is now the fourth SNR with a significant shell morphology at TeV energies. The derived lower limit on the distance of the SNR of 3.2 kpc is used together with radio and X-ray data to discuss the possible origin of the gamma-ray emission, either via inverse Compton scattering of electrons or the decay of neutral pions resulting from proton-proton interaction., Comment: 10 pages, 10 figures, accepted for publication in A&A

Published
2011

16. Study of the electron-positron annihilation coincidence peak two-dimensional pofile

Author

Carlos Takiya, Otaviano Augusto Marcondes Helene, E. do Nascimento, and Vito R. Vanin

Subjects
Nuclear physics, Physics, Positron, Annihilation, Electron–positron annihilation, Astrophysics::High Energy Astrophysical Phenomena, Compton scattering, General Physics and Astronomy, High Energy Physics::Experiment, Electron, Radiation, Pulse shaping, Coincidence
Abstract

Positron annihilation radiation profi le in aluminum was observed with a pair of Ge detectors in coincidence. 22Na was used as a source of positron and the two-dimensional gamma energy spectrum wasfi tted using a model function. Annihilation components of positron at rest with conduction band, 1s, 2s, and 2p electrons were observed. The in-flight positron annihilation was also observed. The model function also took into account the detector response function, relative effi ciency corrections and the gamma backscattering. Coincidences involving a combination of Compton effect, pileup, ballistic defi cit, and pulse shaping problems were treated as well.

Published
2004

17. Virtual compton scattering at Jefferson Laboratory

Author

S. Jaminion, Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), and Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Photon, Proton, 010308 nuclear & particles physics, Nuclear Theory, Compton scattering, Measure (physics), Electron, 01 natural sciences, Coincidence, Nuclear physics, Pion, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Virtual Compton Scattering (VCS) off the proton below pion production threshold allows to measure at fixed four-momentum squared 6 new observables of the proton called the Generalized Polarizabilities. Their determination will put new constraints on models of nucleon structure. Experimentally, we measure an absolute cross section of photon electro-production off the proton (ep → ep γ). At Jefferson Laboratory (Virginia, USA), the scattered electron is detected in coincidence with the recoiling proton in two high resolution spectrometers in order to access the missing particle.

Published
1999

18. ENERGY-DISTRIBUTIONS OF 1.12-MEV GAMMA-RAYS COMPTON SCATTERED BY K-SHELL ELECTRONS OF GOLD, LEAD, AND THORIUM

Author

P. N. Baba Prasad, P. P. Kane, and G. Basavaraju

Subjects
Physics, Photon, Annihilation, Scattering, Gamma ray, Electron shell, Compton scattering, Coincidence circuit, Atomic physics, Coincidence
Abstract

Measurements are reported of the pulse-height distributions of photons of initial energy 1.12 MeV after Compton scattering through 60' and 100' by K-shell electrons of Au, Pb, and Th. The energy distributions of scattered photons, obtained in the case of Au and Pb targets by a deconvolution of the detector response function, show a rise for energies lower than about 0.25 MeV, a broadening of the Compton line, and a negligible shift of the Compton peak. On account of natural radioactivity of the Th target, the corresponding pulse-height distributions are not precise enough to make the deconvolution procedure worthwhile. The energy distributions are compared with theoretical calculations based on the nonrelativistic impulse approximation. It is clear that a relativistic calculation incorporating the e6ects of electron binding in intermediate states is required. In the present experiment, a fast-slow coinci- dence system was used with resolving times of 30 nsec and 2 p, sec, respectively. Pulse-height analysis of anode pulses from the y detector was made with the help of a 20-channel analyzer gated by the output of the coincidence circuit. The lin- earity of pulse height was checked not only through the singles spectra of the y rays of different en- ergies but also through the spectra obtained in the coincidence mode. Annihilation quanta from a Na source, and 1.17- and 1.33-MeV y rays from a ~Co source were used for the spectral measure- ments in the coincidence mode. The photopeaks obtained in the coincidence mode agreed 'with the positions of the corresponding peaks in the singles spectra. Therefore, useful linearity and gain stability checks could be made more frequently in the singles mode than would have been possible in the coincidence mode. If a check showed a pulse- height shift of more than 2%, the corresponding data were discarded. Pulse-height distributions of the scattered y rays were studied at 60' and 100' scattering angles. In each case, the pulse-height distribution of false events was determined and subtracted from the measured distribution in order to obtain the "true" distribution. In all cases, the chance coineidenee rate was less than 1% of the total rate and was con- sidered negligible. The rate in each channel cor- responding to Nz of Eq. (2) in the preceding paper was negligible in the case of the high-Z targets used here. For the reasons mentioned in Sec. II of the pre- ceding paper, the distribution of false events was determined with an equivalent aluminum target in the case of targets of thickness less than 30 mg/cm'. In the case of the thicker lead targets, an equivalent copper target was also used. A cor- rection-had to be made in the case of thorium for its radioactivity. As a result, the errors in the thorium measurements are large.

Published
1977

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