Performance of multichannel FX chip with DC coupled CdTe Schottky detector

This paper describes the performance of multichannel ASIC (called FX) which has been connected with Schottky CdTe detector by DC coupling. Because of DC coupling, leakage current of the detector flows into readout electronics and changes its performance. The I-V characteristics of CdTe Schottky detector have been measured and we have performed both simulation and experimental verification of FX IC behavior vs detector leakage current. Due to the low values of Schottky CdTe detector leakage currents (140 pA for bias voltage of 700 V) performance of FX IC is slightly influenced. Performed measurements show that the gain of readout channel stays constant with changes of leakage current, while the offset voltage at the discriminator input changes linearly of about 4.5mV per 100pA of the detector leakage current.