Shimoyama T, Harano H, Matsumoto T, Moriyama K, Hata T, Kudo K, Koyamada T, Uritani A
National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
Radiat Prot Dosimetry. 2007;126(1-4):130-3. doi: 10.1093/rpd/ncm028. Epub 2007 May 18.
This paper describes the 8-MeV neutron field where the neutrons are generated in the (9)Be(alpha,n)(12)C reaction by bombardment of a beryllium target with a 2.4-MeV (4)He(+) beam from a Van de Graaff accelerator. The neutron field is being prepared for a new national standard on neutron fluence in Japan. Absolute measurement of the neutron fluence was taken using a proton recoil neutron detector, consisting of a silicon surface barrier detector with a polyethylene radiator. Neutron spectra were measured using a newly developed recoil proton spectrometer and a liquid organic scintillation detector. The gamma rays existing in the field were also characterised using a liquid organic scintillation detector. The ambient dose equivalents of the gamma rays were estimated to be <100 microSv at the neutron fluence of 10(7) neutrons cm(-2).
本文描述了一个8兆电子伏的中子场，该中子场是通过用范德格拉夫加速器产生的2.4兆电子伏的氦离子束轰击铍靶，在（9）Be（α，n）（12）C反应中产生中子而形成的。该中子场正在为日本一项关于中子注量的新国家标准做准备。使用由带有聚乙烯散热器的硅面垒探测器组成的质子反冲中子探测器对中子注量进行了绝对测量。使用新开发的反冲质子谱仪和液体有机闪烁探测器测量了中子能谱。还使用液体有机闪烁探测器对该场中存在的伽马射线进行了表征。在中子注量为10（7）个中子·厘米（-2）时，伽马射线的环境剂量当量估计小于100微希沃特。
