1997 Fiscal Year Final Research Report Summary
Development of Neutron Dosimetry System by Helium Accumulation Method
| Project/Area Number |
07558071
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 展開研究 |
|---|
| Research Field |
エネルギー学一般・原子力学
|
|---|
| Research Institution | Oita National College of Technology (1996-1997)
Kyushu University (1995) |
|---|
Principal Investigator |
KANDA Yukinori Oita National College of Technology, Principal, 校長 (40016845)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKAO Yoshiyuki Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Re, 大学院・総合理工学研究科, 助手 (60206711)
|
|---|
| Project Period (FY) |
1995 – 1997
|
| Keywords | Helium Production Cross Section / Helium Accumulation Method / Neutron Dosimetry / Helium Atoms Measurement System / Boron / Ultra-High Vacuum / Dosimeter |
|---|
| Research Abstract |
The purpose of this work is to develop an apparatus to measure low level helium in a solid sample for neutron dosimetry in the practical use such as area monitoring in the long-term and reactor surveillance. The results of this work are as follows.
1. The Helium Aroms Measurement System (HAMS) which can measure helium atoms in the range of 5x10^7-1x10^<15> by utilizing current measurement or pulse measurement for helium detection has been developed by improving an old one. The performance of HAMS answers the purpose of this work. To achieve this performance, the vacuum chambers and vacuum pumping system were redesigned and a pulse conting system was applied to helium measurement.
2. Sample vaporizing condition and method were examined to reduce background gas in helium measurement. (1) An experiment of vaporizing dummy Iron samples to find out sample vaporizing condition which minimized helium background was performed. (2) An sample vaporizing method with radiation from a tungsten heater for helium background reduction was developed. Helium production cross sections of Fe, Pb, asn Sn were obtained by helium gas measurements based on these results.
3. Two types of absolute calibraton methods of the HAMS were developed. One was the helium-ion-implanted sample method. The other was the atmosphere measurement method. The cross-check of the sensitivity of HAMS to helium by using these methods and the standard gas method is important for reliable neutron dosimetry extending over a long period of time.
4. The validity of the neutron dosimetry by the helium accumulation method was confirmed. The amount of helium contained in samples which were irradiated by neutrons with "Yayoi" at University of Tokyo was measured by the HAMS.These results agree with the measured results by another research institute and the estimated values by the multi-foil activation method within the error.
|
