Experimental inspection of the (n, gamman') reaction in heavy nuclei
| Project/Area Number |
07680522
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
エネルギー学一般・原子力学
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
BABA Mamoru Tohoku Univ., Quantum Sci.Ene.Eng., Associate Prof., 工学部, 助教授 (20005466)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MATSUYAMA Shigeo Tohoku Univ., Quantum Sci.Eng.Eng., Reserach Assoc., 工学部, 助手 (70219525)
|
|---|
| Project Period (FY) |
1995 – 1996
|
| Project Status |
Completed (Fiscal Year 1996)
|
| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
|
|---|
| Keywords | (n, gamman, ) reaction / Bi / TOF method / correlation exp / Li(p, n) source / NE213 / dynamic-biasing / 中性子反応 / (n,γn′)反応 / 低バックグラウンド / 信号対雑音比 / 飛行時間法 / n・γ相関測定 / 断面積 / スペクトル |
|---|
| Research Abstract |
The present research aims at the experimental inspection of (n, gamman, ) reaction using a Bi sample and TOF and/or correlation methods.
1.Detector preparation :
We supplemented electronics circuits necessary to do experiments, and prepared a BaF_2 gamma-ray detector having a good energy resolution (<9% for Cs-137 gamma-ray) and a timing resolution (<600ps). For TOF experiments, we optimized the performance of an existing NE213 (5"-diam x2"thick) detector for pulse-height, TOF,and pulse-shape properties, and developed a data processing method based on a dynamic-biasing technique using three-parameter data. It enabled measurements of neutrons lower than 20 ke V.
2.Measurement and Analysis
We carried out TOF experiment for 1-2 MeV neutrons first because problem were foreseen in the correlation methods because of the uncertainty in the overall gamma-ray detection efficiency and the gamma-ray contamination ratio into the neutron detector. The TOF experiments employed a quasi-monoenergetic ^7Li (p, n) source because the updated detector system proved that the monoenergetic T(p, n) source with a Ti-T target have backgrounds neutrons. Up to now, we could not confirm any significant difference between the spectra for Bi and C,Al which have no appreciable (n, gamman, ) cross sections. Thus we have not confirmed yet the evidence of the (n, gamman, ) process. Nevertheless, further experiments will be worthwhile using an updated experimental system and method established in this study because the signal-to-noise ratio is good enough to observe reactions with cross section<1mb/(Sr MeV). The experimental system developed in the present study is useful for other research works too.
|
Report
(3 results)
Research Products
(10 results)
