电荷积分放大电路对测量电离室时间响应速度的影响

摘要

测量放大器的时间响应速度直接影响电离室时间响应速度的测量研究.本文介绍了选用电荷积分放大器设计测量电路的原因,分析了用稳定辐射源照射电离室单元产生阶跃电流信号的机理,提出了通过测量电流信号变化的过程来研究放大器时间响应速度的方法.通过实验研究了放大器的时间响应速度与探测器单元极间电容、放大器输入端保护电阻以及反馈积分电容大小的关系,得出放大器的时间响应速度与电离室极间电容和保护电阻的时间常数有关,而与反馈积分电容大小无关.这为电离室和测量电路的设计提供了理论指导.%The time response speed of measuring amplifier directly influences the research on ionization chamber's time response speed.The reasons why the measuring circuit was designed with charge integration amplifier were presented.The mechanism of emerging stepped current signal of ionization chamber unit irradiated by a stable radiation source was analyzed.The method of studying amplifier time response by measuring the changing process of current signal was proposed.The relationship of the amplifier's time response speed with the detector unit interelectrode capacitance,the amplifier' s input protecting resistance and its feedback integral capacitance was studied through experiment.It is concluded that the amplifier's time response speed is concerned with the constant time of ionization chamber unit interelectrode capacitance and protecting resistance.And it is not concerned with the feedback integral capacitance.It provides theoretical guidance on designing ionization chamber and measuring circuit.