利用252 Cf快裂变室测量BC501A液闪探测器的相对探测效率和响应函数

本文利用²⁵²Cf快裂变室和多参数数据采集系统,逐事例的同时记录了自发裂变中子和瞬发伽马的飞行时间(TOF),脉冲形状甄别(PSD)和反冲能量(RE,裂变中子是通过测量反冲质子;瞬发伽马是通过测量康普顿反冲电子)三维信息.详细介绍了通过离线数据分析完全扣除三维信息中的伽马事例贡献,以获得Φ50.8 mm×50.8 mm的BC501A液闪探测器的相对探测效率和响应函数的方法.在不通过探测器响应函数进行数据转换的条件下,利用中子的能量直接确定了中子的有效测量阈值.得到的中子 关键词： 252Cf快裂变室')" href="#">²⁵²Cf快裂变室 BC501A液闪探测器 相对探测效率 响应函数

Response function and relative efficiency measurements of the BC501A scintillator by using a 252 Cf fast fission chamber

The response function and relative efficiency of a Φ50.8 mm×50.8 mm BC501A scintillator has been measured by using a²⁵²Cf fast fission chamber. In this method,a multi-parameter data acquisition system is employed to take the time-of-flight (TOF),pulse shape discrimination (PSD) and recoil energy (RE. note: fission neutron induces recoil proton while the prompt gamma ray induces Compton recoil electron) of the fission neutron and prompt gamma ray in an event-by-event mode with a TOF gate. The off-line data analysis method for separating the prompt gamma ray from the fission neutron as well as its contribution to the TOF spectrum and RE spectrum to obtain the relative efficiency and response function is discussed in detail. An accurate calibration of the effective neutron detection threshold is carried out by a linear extrapolation of the section around the point of inflexion in the relative efficiency plots using neutron energy directly. The relative efficiency with 0.51 MeV effective neutron detection threshold agrees with the Monte Carlo calculation result of NEFF. The response function from 0.5 MeV to 5 MeV generally agrees with the published experimental result of the NE213 scintillator of the same size.