Design of a Rise Time Discrimination Circuit for X-ray Proportional Counter

Abstract

It is possible to distinguish X-rat events from non X-ray events in proportional counters using the method of rise time discrimination (RTD). In order to subtract non X-ray background, we have developed a simple RTD circuit which will be applied to the proportional counter planned for a sounding rocket experiment. The entire circuit consists of two parts ; the rise time measurement circuit and the time to amplitude conversion circuit which includes the self-calibration mode. From the test with X-ray detecting system, we obtained that the background can be rejected more than 80% in the energy band 2-12keV. However we confirmed that the RDT method is not proper to be used for the energy range above 12keV.