The Research Of 1/f Noise In Nuclear Radiation Detector

Compared with other types of detectors,semiconductor nuclear radiation detectors have obvious advantages,such as high energy resolution,wide linear energy range,shorter pulse rise time and smaller size.That is why the semiconductor nuclear radiation detector has been widely used in nuclear radiation detection.However,the detector will be subject to irradiation damage when it is used in nuclear radiation detection.This kind of damage is mainly lattice defects such as gaps and vacancies in the detector material.The existence of lattice defects,which is the source of 1/f noise,will change the electrical properties of the detectors.In order to understand the relationship between irradiation damage and 1/f noise of semiconductor nuclear radiation detector,the 1/f noise of semiconductor nuclear radiation detector is tested and analyzed in this thesis.Firstly,the principle of electrical noise and the working principle of semiconductor nuclear radiation detector are introduced.The relationship between irradiation damage and 1/f noise of semiconductor nuclear radiation detector is analyzed.Then,three kinds of 1/f noise mathematical models are introduced and compared,by which the 1/f noise is generated.The comparison shows that the 1/f noise generated based on the Fractional Brownian Motion model has good performance on frequency domain and long range correlation.After that,the parameter estimation method of 1/f noise is introduced and compared in detail.The results show that the estimation error of the 1/f noise spectrum characteristic parameters is less than 1.3% based on the wavelet estimation method when the SNR is greater than 0 dB,and the estimation error of the noise amplitude is less than 2.6%,therefore it is suitable for the estimation of 1/f noise parameters under white noise background.Finally,the test platform for 1/f noise in semiconductor nuclear radiation detector was built to test and analyze the 1/f noise of irradiated and non-irradiated detectors in different sizes.The results show that the lattice defect produced by irradiation results in obvious change of the 1/f noise.The spectrum characteristic parameter of 1/f noise is related to the size of the detector,and the noise amplitude is related to the size of the detector,the irradiation dose and the bias voltage.Thus,1/f noise can be used to assess the performance degradation of semiconductor nuclear radiation detectors,and become the indicator of reliability evaluation and detector screening.