| Project/Area Number |
10480113
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Nuclear engineering
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
NAKAMURA Takashi Tohoku University ・ Graduate School of Engineering ・ Professor, 大学院・工学研究科, 教授 (70026029)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKADA Masashi National Institute of Radiological Sciences ・ International Space Radiation Laboratory ・ Researcher, 国際宇宙医学研究センター, 研究員(研究職) (50291109)
YAMADERA Akira Tohoku University ・ Cyclotron and Radioisotope Center ・ AssociateProfessor, サイクロトロン・ラジオアイソトープセンター, 助教授 (90004465)
BABA Mamoru Tohoku University ・ Cyclotron and Radioisotope Center ・ Professor, サイクロトロン・ラジオアイソトープセンター, 教授 (20005466)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Project Status |
Completed (Fiscal Year 1999)
|
| Budget Amount *help |
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1998: ¥2,900,000 (Direct Cost: ¥2,900,000)
|
|---|
| Keywords | Mixed field / Neutron Spectra / Phoswich detector / Space enviroment / Liquid scintillator / Plastic scintillator / Response function / 中性子 / 荷電粒子 / 有機液体シンチレータ / 粒子弁別 / 荷電粒子混在場 / ホスウィッチ検出器 / 高エネルギー加速器 |
|---|
| Research Abstract |
Neutron spectra have scarcely been measured on board a spacecraft or an aircraft, because the neutron measurement requires a discrimination between neutron and charged-particle events. In this viewpoint, we have developed a new phoswich detector consisting of an NE213 liquid scintillator (133mm diam. X 133mm long) surrounded by an NE115 plastic scintillator (10mm thickness). The light induced by charged particles in the NE115 scintillator has a long characteristic decay time constant of 225nsec, whereas the light by recoil protons from neutrons in the NE213 has the time constant of 30nsec. These differences in the light-decay time constant make it possible to separate pulses of the different particle species. This detector can measure the neutron spectrum up to about 130MeV by discriminating between neutron and charged-particle events in a mixed field in space.
A mixed field of neutrons and charged particles were produced by bombarding 70MeV protons on a 2mm thick Be target at the NIRS
… More
(National Institute of Radiological Sciences) cyclotron facility and by bombarding 100MeV/n carbon ions on stopping length carbon or aluminium target at the HIMAC (Heavy Ion Medical Accelerator in Chiba) in the NIRS. The detector was placed at 3〜5m downstream from the target at 0〜45deg. To the beam axis. It was found that this phoswich detector was able to discriminate neutron and gamma-ray events from incident charged-particle events.
The response functions of the phoswich detector to neutrons were measured with neutrons from the Be+C target bombarded by 135MeV protons from the RIKEN (Institute of Physical and Chemical Research) ring cyclotron. The measured response functions for neutrons were compared with Monte Carlo calculations, SCINFUL code. From these experimental and calculated response functions, the response matrices were completed for neutrons up to 130MeV. By unfolding the experimental spectra with the FERDOU code, the gamma-ray and neutron spectra in a mixed field of neutrons and charged particles at NIRS cyclotron were obtained. Less
|
