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Development of a dual counter type neutron spectrometer for the direct measurement of neutron energy spectra

直接测量中子能谱的双计数器型中子能谱仪的研制

基本信息

批准号：
04680228
负责人：
AOYAMA Takahiko
金额：
$ 1.02万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04680228/
关键词：
Neutron detection Neutron spectrometer Proton recoil counter _3He proportional counter Delayd coincidence method Full energy absorption Energy response function Monte Carlo calculation

项目摘要

A full-energy-absorption neutron spectrometer using dual concentric proportional counters has been devised to obtain neutron energy spectra directly from pulse height spectra without unfolding fot neutron energy range from 10 keV to 1 MeV.1. A hollow cylindrical multi-anode proton-recoil counter with a large volume (-5 lit.) filled with propane at 3 atm was designed and constructed to obrain a high proton recoil probabitity, and a commercial _3He counter was installed in the hollow counter coaxially.2. An energy resolution of 23% was obtained with the proton recoil counter for 764 keV equivalent proton energy, and a gamma-ray rejection rate of 95% was attained for gamma-ray energies of the order of 1 MeV using pulse shape discrimination.3. A pulse procession circuit was constructed to obtain delayd coincidence between proton-recoil and neutron-capture signals and to generate gate signals for a multichannel analyzer. Total electronics including the circuit was constructed to analyze the height of full-energy-absorption proton-recoil pulses alone.4. Irradiation of monoenergetic neutrons with an energy berween 80 and 600 keV on the spectrometer evidenced the appearance of a single peak on a pulse height spectrum corresponding to the full-energy-absorption as abserved in the energy response functions calculated by Monte Carlo computer simulation. An energy calibration curve was obtained by using the pulse height spectra. Observed neutron detection efficiencies of the same order as those of calculated assured the reliability of the Monte Carlo calculation.

设计了一种使用双同心正比计数器的全能量吸收中子能谱仪，可以直接从脉冲高度谱获得中子能谱，而无需展开 10 keV 至 1 MeV 的中子能量范围1。为了获得较高的质子反冲概率，设计并构造了一个大体积（-5升）的空心圆柱形多阳极质子反冲计数器，其中充满了3 atm的丙烷，并在空心计数器内同轴安装了商用_3He计数器。 2．质子反冲计数器对于764 keV当量质子能量获得了23%的能量分辨率，对于1 MeV量级的伽马射线能量，利用脉冲形状辨别获得了95%的伽马射线抑制率。 3．构建脉冲处理电路以获得质子反冲信号和中子俘获信号之间的延迟重合，并为多通道分析器生成门信号。构建了包括电路在内的整个电子器件来单独分析全能量吸收质子反冲脉冲的高度。 4．能量在 80 和 600 keV 之间的单能中子在能谱仪上的辐照证明，在与蒙特卡罗计算机模拟计算的能量响应函数中观察到的全能量吸收相对应的脉冲高度谱上出现了单峰。通过使用脉冲高度谱获得能量校准曲线。观测到的中子探测效率与计算的中子探测效率处于同一数量级，保证了蒙特卡罗计算的可靠性。