活化法测量散裂靶中子能谱的实验验证

散裂靶中子的能谱对加速器驱动次临界系统的倍增因数和嬗变率等影响很大,计算表明散裂靶中子谱在MeV能区与裂变中子谱相近。本文利用活化法测量临界装置的泄漏中子谱和中子注量率,提出了用In、Al、Mg、Ti、Au、Zn、Ni、Rh、Fe和Co等活化箔测量散裂靶中子能谱和中子注量率的方案。结果表明,将活化箔在散裂靶中子场中辐照5h,中子注量最高达5×1014 cm-2量级,辐照后1h内取出活化箔,根据半衰期的长短安排测量顺序,可测量散裂靶的中子能谱和中子注量率。

Experiment Verification of Measurement for Neutron Spectrum of Spallation Source by Activation Method

The spectrum of spallation neutron source is of great influence on the multiplication factor and transmutation rate of ADS. It is shown that the spectra of spallation target neutron and fission neutron are similar in MeV region. In this paper, the leakage neutron spectrum and neutron fluence rate of the critical assembly were measured by activation method with In, Al, Mg, Ti, Au, Zn, Ni, Rh, Fe and Co foils as activation foils. The results show that the activation method can be used to measure the neutron spectrum in the spallation target neutron field. The neutron fluence should be up to 5×10¹⁴ cm^-2 in 5 h. The activation foils should be taken out in 1 h after irradiation. The measure order is according to the length of the half-life.