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Study of Pulse Shape Discrimination of Sub-MeV Neutrons From Gamma-Rays with Liquid Scintillator
M. Yoshioka,M. Ueyama,Y. Koba,Y. Nakamura,T. Kajimoto,D. Moriguchi,Y. Uozumi,N. Shigyo 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
We have studied pulse shape discrimination of sub-MeV neutron from spallation nuclear reactions. Neutron measurements were carried out with a 2-inch NE213 scintillator viewed by a phototube (HAMAMATSU H1949) for the carbon-carbon reaction at 290 MeV/n. Neuron energies were measured with the TOF technique by using a timing pick-up plastic scintillator. Output signals of detectors were digitized and stored with a digitizer (Acqiris DC282). The digital pulse shape discrimination (DPSD) has been investigated through comparison between three different analyzing algorithms. Effects on the neutron-gamma (n/g) discrimination were also investigated after the subtraction of background and abnormal events. Moreover, in order to realize better n/g discrimination the detector system was cooled down to about zero degrees centigrade by Peltier devices to suppress the dark current of the phototube which would be the main cause distorting pulse shapes. Experimental studies were made in terms of the temperature dependence of detector performance including pulse shape.
Measurement of Deuteron Induced Thick Target Neutron Yields at 9 MeV
N. Shigyo,K. Hidaka,K. Hirabayashi,Y. Nakamura,D. Moriguchi,M. Kumabe,H. Hirano,S. Hirayama,Y. Naitou,C. Motooka,C. Lan,T. Watanabe,Y. Watanabe,K. Sagara,S. Maebaru,H. Sakaki,H. Takahashi 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The double differential thick target neutron yields from 9 MeV deuteron incidence were measured at the Kyushu University Tandem Accelerator Laboratory. A copper and a titanium foils which are thick enough for a deuteron to stop in the foils were placed at the center of a vacuum chamber. An NE213 liquid organic scintillator was employed to detect neutrons emitted from targets and placed at 9 directions from 0˚ to 140˚. To consider the contribution of scattered neutrons from the floor, we also measured neutron yields with an iron shadow bar located in front of the scintillator. Because incident deuteron beam was not pulsed and the Time-of-Flight method was not applied, the energy spectrum was derived from unfolding the light output spectrum using the FORIST code. The detection efficiency was calculated with the SCINFUL-QMD code. The experimental results were compared with the calculation data of the TALYS code, and it turned out that the calculation data does not reproduce the experimental ones satisfactorily.
Status of JENDL High Energy File
Y. Watanabe,K. Kosako,S. Kunieda,S. Chiba,R. Fujimoto,H. Harada,M. Kawai,F. Maekawa,T. Murata,H. Nakashima,K. Niita,N. Shigyo,S. Shimakawa,N. Yamano,T. Fukahori 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The present status of the JENDL high-energy file is reported. The recent version (referred to as JENDL/HE-2007) contains neutron and proton cross section data for energies up to 3 GeV for 107 nuclides over the wide mass range from H to Am. The newly evaluated data for 41 nuclides have been added to the first version (JENDL/HE-2004) along with some revisions. The JENDL/HE-2007 includes neutron total cross sections, nucleon elastic scattering cross sections and angular distributions, nonelastic cross sections, production cross sections and double-differential cross sections of secondary light particles (n, p, d, t, ^3He, α, and π) and gamma-rays, isotope production cross sections, and fission cross sections in the ENDF-6 format. The evaluations were performed on the basis of experimental data, nuclear model calculations, and systematics based on measurements. The evaluated cross sections are compared with available experimental data and the other evaluations. Some results of benchmark tests with MCNPX codes are shown.
T. Kajimoto,N. Shigyo,K. Ishibashi,D. Moriguchi,Y. Nakamura,H. Arakawa,S. Kunieda,T. Watanabe,R. C. Haight 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
We measured neutron-production double-differential cross-sections by neutron incidence from 50 to 150 MeV. A ^(238)U fission ionization chamber was set to take the incident-neutron flux. Six NE213 liquid scintillators which had a thickness of 12.7 cm and 12.7 cm in diameter, were placed at 15˚, 30˚, 60˚, 90˚, 120˚, and 150˚ to detect neutrons emitted from a sample. The energy of incident neutron was determined by the time of flight (TOF) technique. The energy spectra of neutron emitted from the sample were derived by the unfolding their light output spectra with the response functions of the detectors. The response functions were measured with the spallation neutrons above 25 MeV. In the unfolding process, we assumed that neutron energy spectra reproduced the shape by the moving source model. The neutron-induced neutron-production double-differential cross sections were parameterized with the moving source model by the least-square method. The experimental results were compared with calculations of the PHITS and the TALYS codes.
Kajimoto, T.,Shigyo, N.,Sanami, T.,Iwamoto, Y.,Hagiwara, M.,Lee, H.S.,Soha, A.,Ramberg, E.,Coleman, R.,Jensen, D.,Leveling, A.,Mokhov, N.V.,Boehnlein, D.,Vaziri, K.,Sakamoto, Y.,Ishibashi, K.,Nakashim North-Holland Physics Pub 2014 Nuclear instruments & methods in physics research. Vol.337 No.-
The energy spectra of neutrons were measured by a time-of-flight method for 120GeV protons on thick graphite, aluminum, copper, and tungsten targets with an NE213 scintillator at the Fermilab Test Beam Facility. Neutron energy spectra were obtained between 25 and 3000MeV at emission angles of 30<SUP>o</SUP>, 45<SUP>o</SUP>, 120<SUP>o</SUP>, and 150<SUP>o</SUP>. The spectra were parameterized as neutron emissions from three moving sources and then compared with theoretical spectra calculated by PHITS and FLUKA codes. The yields of the theoretical spectra were substantially underestimated compared with the yields of measured spectra. The integrated neutron yields from 25 to 3000MeV calculated with PHITS code were 16-36% of the experimental yields and those calculated with FLUKA code were 26-57% of the experimental yields for all targets and emission angles.
Measurement of Neutron-Production Cross Sections for 290 MeV/u Carbon Ion Incidence
D. Moriguchi,Y. Nakamura,T. Kajimoto,Y. Koba,M. Ueyama,M. Yoshioka,N. Shigyo,Y. Uozumi,D. Satoh,T. Sanami,M. Takada,N. Matsufuji 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
Neutron-production double-differential cross sections for 290 MeV/u carbon-ion incidence on carbon target were measured with NE213 liquid organic scintillators by time-of-flight technique. NE213 liquid organic scintillators 12.7 cm in diameter and 12.7 cm thick were placed in the directions of 15˚, 30˚, 45˚, 60˚, 75˚, and 90˚. The typical flight path length was 4.0 m. In order to reduce neutrons from the beam dump, an iron and a concrete shield was placed between the detectors and the beam dump. For measurement of background, a shadow bar was set between the target and each detector. Neutron detection efficiencies were obtained by calculations with a Monte Carlo simulation code SCINFUL-QMD. The cross sections were obtained for neutron energy above 2.8 MeV. The experimental results were compared with the calculation data of the PHITS code.
Neutron-Production Double-Differential Cross Sections from Heavy-Ion Interactions
D. Satoh,D. Moriguchi,T. Kajimoto,Y. Koba,Y. Nakamura,N. Shigyo,M. Ueyama,Y. Uozumi,M. Yoshioka,N. Matsufuji,M. Takada,T. Sanami 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The existing data of neutron-production double-differential cross sections on C, Cu, and Pb targets bombarded with heavy-ions from He to Xe at 230 - 600 MeV/nucleon were revised by using a new set on neutron-detection efficiency values of an NE213-type liquid organic scintillator calculated with SCINFUL-QMD. The revised data were compared with the experimental data obtained by our new measurements, and the predictions of the Monte-Carlo particle transport codes, PHITS, FLUKA, MCNPX, and Geant4. While the revised and new experimental data showed good agreement, the Monte-Carlo codes failed to reproduce the high-energy peaks in the forward angular region.