방사선 계측 계수율 향상을 위한 자가 초기화 전치 증폭기

Abstract

This work presents a self-reset configuration of front-end circuits for radiation sensorsto reduce pile-up events and measurement time while maintaining energy information. Theproposed system includes delay circuit, comparator, and switch transistor to detect the falling timemoment and then immediately send a reset signal to a switch transistor connected on the feedbackloop of a preamplifier. When the op-amp starts generating a normal output signal induced froma radiation detector, the delayed circuit will also get the preamplifier output as an input signal toproduce a delayed signal. Then, the comparator compares both of the normal output and delayedsignal to generate on- and off- signals for a transistor switch. Finally, the normal output wouldinstantly return to a baseline and be prepared state for the next radiation impact event on thedetector instead of decaying away with a long trail. This self-reset technique would dramaticallyreduce the dead time to 137 ns which can be used in direct radiation measurements under highactivity environments. This technique can be adopted in many applications that require a highspeed measurement systems, for instance, patient and cargo scanning technologies, radiationmonitoring in nuclear plant facilities or developing advanced high energy physic experimentalfacilities.