Low-power charge sensitive amplifier for semiconductor scintillator

A design of low-noise charge sensitive amplifier (CSA) for measurement of optical response of photo-detector registering light produced by semiconductor scintillator is presented. Detailed analysis of the CSA suitable for large parasitic detector capacitance is provided, regarding noise, power and stability. Two scenarios where input transistor is biased in strong inversion and weak inversion are compared, with included accurate 1/f noise modeling. The experimental prototype was implemented in 0.5 μm CMOS process with a 5 V power supply.