【作者】 胡传皓； 曾国强； 葛良全； 容易； 卿松；

【Author】 HU Chuanhao;ZENG Guoqiang;GE Liangquan;RONG Yi;QING Song;Nuclear Technology Key Laboratory of Earth Science, Chengdu University of Technology;

【机构】 成都理工大学四川省地学核技术重点实验室；

【摘要】 本文设计了一种基于结型场效应晶体管源级复位的电荷灵敏前置放大器。该电路由两个核心部分组成,分别为由N沟道结型场效应晶体管和高频三极管级联构成的高增益放大电路;由电平比较器、脉冲发生器和高速模拟开关构成的复位电路。该前置放大器采用脉冲复位工作方式,当输出阶梯信号幅值达到触发阈值时复位电路输出负脉冲,使场效应管处于正向偏置,积分电容通过该正向导电沟道泄放电荷,使电路恢复正常工作状态。相比于阻容反馈式电荷灵敏前置放大器,该复位型前放不使用大阻值反馈电阻,因而降低了电阻引入的噪声;采用周期复位方式,能够有效避免大阻值反馈电阻造成的电荷泄放时间较长,脉冲堆积严重的问题。因此,该复位型前放非常适用于Si-PIN、SDD、HPGe等高分辨率、高计数率探测器。更多还原

【Abstract】 A charge-sensitive preamplifier based on the source reset of junction field effect transistors was designed. The circuit consists of two key parts, one of which is a high-gain amplifier circuit consisting of a cascade of N-channel junction field effect transistors and high-frequency transistors, the other is a reset circuit consisting of a level comparator, a pulse generator, and a highspeed analog switch. The preamplifier adopts a pulse reset working mode. When the amplitude of the output ladder signal reaches a trigger threshold, the reset circuit outputs a negative pulse, so that the field effect transistor is forward biased, and the integral capacitance discharges the charge through the forward conductive channel, so that the circuit resumes normal operation. Compared to the R-C feedback charge-sensitive preamplifiers, this reset-type preamplifier does not use a largeresistance feedback resistor, thus reducing the noise introduced by the resistor; using a periodic reset method can effectively avoid the long time of charge discharge and the serious pulse pile-up caused by the large feedback resistor. Therefore, the reset preamplifier is very suitable for high resolution, high count rate detectors such as Si-PIN, SDD and HPGe更多还原