Development of a measurement method of the absolute neutron emission rate using a multi-layered manganese bath detector

2014 Fiscal Year Final Research Report

• Project/Area Number: 24760057
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Applied physics, general
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: MATSUMOTO Tetsuro 独立行政法人産業技術総合研究所, 計測標準研究部門, 主任研究員 (70415793)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 中性子放出率 / マンガン / 放射化 / 中性子線源 / NaI(Tl)検出器 / 不確かさ

Outline of Final Research Achievements

Radioactive neutron sources such as 252Cf and 241Am-Be(a,n) are used for various purposes. The neutron emission rate (neutrons per second) of the neutron source is very important for radiation protection and safety management. In the present study, we develop a new type of manganese bath for determination of neutron emission rate of a radioactive neutron source. The manganese bath has a multilayered structure composed of polyethylene plates and manganese alloy plates containing 70 % manganese. In measurements of neutron emission rate, a neutron source is set in the center of the manganese bath at first. 56Mn is produced by the 55Mn(n,g)56Mn reaction. The neutron emission rate is finally determined by measuring gamma rays emitted from 56Mn using a NaI(Tl) scintillation detector with a 5.08 cm diameter and a 5.08 cm length and a high purity Ge detector with relative efficiency of 60 %.

Free Research Field

中性子計測