One- and Two-Pole Compensation of Charge- Sensitive Amplifiers With Resistive Feedback to Improve the Energy Resolution in GRETA

The gamma-ray energy tracking array (GRETA) is a detector system currently under construction in the USA. The energy of the gamma ray is measured in real time inside field-programmable gate array (FPGA), employing the typical processing chain of the shaper, pole–zero compensation (PZC), baseline restoration, and pulse high analysis. In this article, we propose a two-pole PZC for GRETA based on the analysis of the charge-sensitive amplifier (CSA). We derived the time- and discrete-domain versions of the PZC and implemented the discrete version. We present the implementation of the two-pole PZC inside an FPGA to meet the high computational rate required for GRETA. The full-width at half-maximum (FWHM) energy resolution of the 60Co 1.33-MeV line at 100 kgammas/s was improved by about 23% for the two-pole PZC compared to the one-pole PZC.