基于Si-PIN探测器的电流型计数式α粒子测量

为解决基于Si-PIN探测器的传统计数型粒子测量系统在测量低强度脉冲辐射场时存在的计数率低和不能直接测量粒子时间信息的问题,提出了电流型计数测量方法。其原理是对电流型Si-PIN探测器在粒子入射时输出的脉冲信号进行线性放大和高速数字化,并使用数字信号处理算法进行数据分析以获得粒子测量信息。利用电流型Si-PIN探测器、电流型前置放大器和高带宽数字示波器组建了电流型计数测量系统,并在241 Am-244 Cm和239 Pu源上开展了α粒子测量实验。实现了脉冲幅度谱和粒子入射时间的联合测量,同时利用FIR及IIR型数字滤波器改善了能谱测量的能量分辨率。系统的最大计数率达2×106 s-1,适用于低强度脉冲辐射场测量。

Current-mode-counting Measurement of α-particle with Si-PIN Detector

The current-mode-counting measurement method was proposed to overcome the shortcomings of traditional counting system with Si-PIN detector such as relatively low count rate and the inconvenience of time information measurement of particles in low intensity pulsed radiation measurement. In the method, the pulse generated by Si-PIN detector as induced by incident particle was amplified linearly and then digitized at high speed, and the spectrum was acquired by digital signal processing algorithms with the waveform data. The current-mode-counting measurement system was developed with Si-PIN detector, current-sensitive preamplifier and wideband digital oscilloscope. Experiments were carried out with ²⁴¹Am-²⁴⁴Cm and ²³⁹Pu sources, and spectra and time distributions of incident α-particles were acquired. The energy resolution of spectra was enhanced by FIR and IIR digital filters in data processing. The count rate is up to 2×10⁶ s^-1, and the system is suitable for the measurement of low intensity pulsed radiation field.