Development of a new type neutron dosimetry system for a long-range neutron energy

1992 Fiscal Year Final Research Report Summary

• Project/Area Number: 02558024
• Research Category: Grant-in-Aid for Developmental Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: Nuclear engineering
• Research Institution: KYUSHU UNIVERSITY
• Principal Investigator: KANDA Yukinori Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Professor, 総合理工学研究科, 教授 (40016845)
• Co-Investigator(Kenkyū-buntansha): KAWANO Toshihiko Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Re, 総合理工学研究科, 助手 (30234090) ; TAKAO Yoshiyuki Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Re, 総合理工学研究科, 助手 (60206711)
• Project Period (FY): 1990 – 1992
• Keywords: Helium production cross section / Helium accumulation method / Neutron dosimetry / Helium / Neutron / Alpha particles

Research Abstract

A new type neutron dosimetry system by using helium accumulation method has been studied. It is useful to neutron dosimetry in fast neutron irradiation fields such as the first wall of fusion reactor or the experiment of incineration of radioactive waste e.g. TRU.
This system requires He-production cross sections and the Helium atoms measurement system (HAMS). But the experimental data for He-production cross sections are few. Therefore it is necessary that the cross sections are measured. The measurements are difficult because the number of He atoms produced in samples, which are irradiated at a experimental facility for measuring the cross sections, is a few atoms of -1X10^<10> on a calculation. Fir st of all, we have to develop HAMS which have high sensitivity to He atoms. The results of this study are described below.
Appropriate designs of vacuum system and trap to purify a He gas sample, the procedure of He measurements, and degassing allow HAMS, which has been developed in this study, to measure 1X10^<10> He atoms in a Al sample to an accuracy of *5%. And a method to calibrate measuring efficiency of HAMS in the range of -1X10^9 He atoms have been developed.
Because of nuclear reaction, high energy alpha-particles are produced and some of them leave from a sample. Two kinds of methods to exclude the effect of alpha-particles loss have been developed.
The He-production cross sections of Al, Si, and C for near 14MeV neutrons have been measured by using HAMS. The samples were irradiated with FNS a JAERI.
A excitation function of Al(p,xalpha) reaction for the proton energy range of 0-18MeV have been measured. Al samples were irradiated with tandem Van de Graaff accelerator at Kyushu University.