Signal processing and noise analysis on realistic radiation detector model

Abstract

In this paper, equations for signal processing and noise analysis were derived for a realistic radiation detector model, and simulations were performed under various conditions. Realistic radiation detector model was composed of silicon PIN diode detector, Charge Sensitive Amplifier (CSA), and CR-RC2 shaper. For the realistic CSA model, a finite bandwidth model with a single pole response amplifier was presented and related equations were derived. Through realistic CSA model, it was possible to calculate the signal distortion phenomena such as charge transfer loss and ballistic deficit of the actual circuit and the noise value of the CSA output stage. For the realistic shaper model, signal and noise transfer functions were derived for the CR-RC2 circuit with non-inverting amplifier. In particular, the equation for the internal noise of the shaper, which has been ignored in the current noise analysis, was derived. Through this, it was possible to analyze the effects of amplifier characteristics, resistance value, and signal gain for each stage on the overall noise in the radiation detector of the CSA–shaper structure. For comparison with the simulation, a circuit equivalent to the realistic radiation detector model was made and measurements under the same conditions as the simulation were made. As a result of the verification experiment, the measured values matched well with simulations under various conditions, and through this, the validity of this model was verified. Signal processing and noise analysis were mainly performed for PCB circuits using commercial components, but also included content for CMOS front-end detectors. This model consists only of analytic formulas for the time domain function and the transfer function, nonetheless it has been shown to give accurate results.