适合新型便携式高能中子剂量仪的模拟电路系统设计

Design of an Analog Circuit System for a New Portable Dose Detectors Used for High-Energy Neutrons

介绍了一种适合于便携式二元慢化型高能中子剂量仪的模拟电路系统的设计解决方案。该方案采用低噪声结型场效应管和高性能运算放大器构成具有暗电流消除功能的电荷灵敏前置放大器。前置放大器信号经极零相消后由一级二阶S-K滤波器和低通滤波器成型放大为满足后续电路需求的准高斯信号,然后经过甄别电路和单稳态成型电路把模拟脉冲变成固定宽度的数字脉冲,以便于后续数字电路的进一步处理。由Multisim电路仿真软件仿真结果和实际电路测试结果可知,在计数率从0.1～20 kHz范围内,该方案完全满足便携式二元慢化型高能中子剂量仪的信号处理要求。

It presents a solution of an analog circuit system for a kind of portable Dual -Moderated Dose Detec-tors for High-Energy Neutrons .Using low-noise JFET and high -performance operational amplifier , a kind of charge-sensitive preamplifier with the function of dark current cancellation was set up .Signal from the pre-amplifier was processed by an analog system made up with pole -zero cancellation circuit , second order S -K filter and low-pass filter circuit to form a signal with quasi -Gaussian shape and enough amplitude , which met with the demands of subsequent digitalization circuit .The digitalization circuit was formed by a pulse amplitude discriminator , based on the Schmitt trigger , and a mono -stable trigger and the signal would become a fixed width of digital pulses , which could be read and processed by MCU -cored data acquisition system .Both re-sults from the simulation of EDA software （ Multisim） and the actual circuit test indicated that this design whol-ly met the signal-processing requirements of Dual -Moderated Dose Detectors for High -Energy Neutrons in the count rate range from 0.1~20 kHz.