CMOS low noise switched charge sensitive preamplifier for CdTe X-ray detection

A CdTe detector readout based on MOS switched charge sensitive preamplifier without feedback resistor is presented. CMOS technology allows high integration level, relatively low power consumption and provides a nearly ideal switch that does not introduce significant drift current to the integration capacitor. No external components are required. CdTe detectors combine low current with high resistivity and low capacitance that reduces noise levels. Noise performance is compared for semi-Gaussian pulse shaping and a low pass filter limiting of the preamplifier output. The more direct second approach exhibits very similar performance in comparison to the first one, due to 1/f noise; and can be better for specific shaping and reading times.