Discrete time domain analysis of radiation detector noise

Abstract In this paper, the analysis of radiation detector noise is carried out based on digital signal processing in the discrete time domain. To generate accurate noise models, detector noise sources are analyzed and modeled in the discrete region. Poisson noise generator was used for shot noise, and White Gaussian Noise Generator was used for Johnson Noise and Channel Thermal Noise. For flicker noise, White Gaussian Noise Generator with 1/ f filter was applied. The output noise was calculated by convolution sum of the system impulse function and noise input. In order to improve the accuracy noise analysis, the time domain equation was derived based on the advanced model compared to the existing noise model. CSA model based on a realistic limited-bandwidth OP-AMP. For the realistic detector model, Laplace transformed function of CSA and shaper out signal for Parallel and series noise were derived and inversed for time domain signal. The results of the existing frequency domain analysis match well with the discrete time domain analysis. The discrete time domain analysis can increase the accuracy of noise investigation because it can visualize the results of existing frequency domain models and provide different representation methods for the same results.