宽量程fA级电离室电流测量

Current Measurements of Wide Range fA Level in Ionization Chamber

针对辐射探测中电流电离室输出电流十分微弱,且电流范围较宽,模拟电路处理困难,难以达到精确测量等问题,设计了可检测nA级到fA级的宽量程电流电离室微弱电流计。提出了以高精度前置放大电路、高分辨率模数转换为基础,从电气隔离、恒温控制、电磁屏蔽等方面,解决模拟处理电路微弱信号易受温度漂移、湿度、电磁干扰影响等问题的方法,从而提高了测量的分辨率。经验证,测量的分辨率达到±1 fA。

In the field of radiation detection,the output current of current ionization chamber is very weak,and the current range is wide.Thus,it is difficult to design such analog circuits and to reach more precise measurements.To achieve this,an ionization chamber faint galvanometer is designed to detection broad range current from nA level to the fA level in the paper.Based on precision preamplifier,high-resolution analog-to-digital conversion,the solution was drawn from electrical isolation,temperature control,electromagnetic shielding,etc.,to solve the problems that weak signal is susceptible to temperature drift,humidity,electromagnetic interference effect.The verification indicates that measurement resolution achieved 1fA.