Measurement of Continuous Energy Neutron Incident Neutron Production Double Differential Cross sections

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 12480141
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nuclear engineering
• Research Institution: Kyushu University
• Principal Investigator: ISHIBASHI Kenji Kyushu University, Faculty of Engineering, Professor, 大学院・工学研究院, 教授 (00159766)
• Co-Investigator(Kenkyū-buntansha): NAKAMURA Takashi Tohoku University, Faculty of Engineering, Professor, 大学院・工学研究科, 教授 (70026029) ; ARIMA Hidehiko Kyushu University, Faculty of Engineering, Research Associate, 大学院・工学研究院, 助手 (20253495) ; SHIGYO Nobuhiro Kyushu University, Faculty of Engineering, Research Associate, 大学院・工学研究院, 助手 (40304836) ; MEIGO Shin-ichiro Japan Atomic Energy Research Institute, Resercher, 中性子科学研究センター, 研究員 ; TAKADA Hiroshi Japan Atomic Energy Resarch Institute, Researcher, 中性子科学研究センター, 研究員
• Project Period (FY): 2000 – 2002
• Keywords: Continuous Energy Neutron Incidence / Neutron Production Cross / Phoswich Detector / NaI(TL) Scintillator / Plastic Scintillator / Recoil Proton Method

Research Abstract

The neutron-production double-differential cross sections for neutron incidence up to 800 MeV were measured up to 800 MeV at Los Alamos Neutron Science Center (LANSCE). The incident neutrons have continuous energies as emitted neutron at the facility. The energy of emitted neutron was obtained by the deposition energy of recoil proton from the radiator. The energy of incident neutron was determined by the time-of-flight method and the emitted neutron energy.
First, the two sizes of phoswich type recoil proton detectors consist of Nal(Tl) and plastic scintillator were constructed and tested by the continuous energy neutron generated from the spallation reaction by Ar beam and Pb target at National Institute for Radiological Science (NIRS). Next, the detectors were checked by mono energetic proton up to 500 MeV at High Energy Accelerator Research Organization (KEK), We obtained the characteristics of the detectors experimentally.
Then we measured the neutron-incident neutron-production (n, xn) double-differential cross sections at LANSCE. The irradiated targets were an iron and a lead. The detection angles were 15, 30 and 90 degrees. It was difficult to discriminate the neutron events from the background ones for the smaller phoswich detectors. To increase the detection efficiency, the combination of organic scintillator and the time-of-flight method was adopted. The scheme made the discrimination much clear and was effective for lower energy emitted neutron below 100 MeV.
The capability of the measurement of (n, xn) double-differential cross sections for the continuous incident energy neutron was shown in this study.