Study And Test Of Energy Spectrum Reading Of Pixel And Hemispherical Cadmium Zinc Telluride Detectors

With the wide application of nuclear technology in nuclear energy applications,nuclear medical imaging,industrial non-destructive testing,homeland security,astronomy,and cutting-edge physics,people are increasingly demanding performance from nuclear radiation detectors.The development of a nuclear radiation detector that can work at room temperature environment and has high performance in terms of energy resolution,spatial resolution,and detector efficiency has become a key research direction in this field.Cadmium zinc telluride（Cd Zn Te or CZT）detector which has emerged in recent years is a new type of compound semiconductor detector.It has attracted much attention because of its high energy resolution,high spatial resolution and high detection efficiency,and can work at room temperature normally,and has good portability.With the support of the National Natural Science Foundation of China,"Key Technology Research on Precise Positioning of Rays and the Position of CZT Detector"（No.11805215）,relying on the resources and platform of the Institute of High Energy Physics of Chinese Academy of Sciences Research,the thesis carried out research on related technologies of energy spectrum testing based on CZT detector.The main research contents and results are as follows:1.According to the characteristics of the output signal of the CZT detector,the analog signal readout circuit that we designed mainly includes a low noise charge sensitive preamplifier circuit,a filter shaping amplifier circuit,a peak hold circuit,a timing circuit and a power supply circuit.The performance of the designed low-noise charge-sensitive preamplifier circuit was tested by a laboratory separation device,and its electronic noise was lower than 2ke V（1Me V）.The experimental test results of the analog signal readout circuit designed in this paper show that the readout circuit has a high signal-to-noise ratio,which reduces the impact of electronic noise on the detector signal and effectively improves the detector energy spectrum performance.2.Using the finite element method to simulate the weight potential distribution in the pixel-type CZT crystal that used in the experiment,and approximately evaluate the unipolar region inside the crystal according to the weight potential distribution.Build an experimental platform to obtain the relationship between the depth information and the charge collection efficiency inside the pixel-type CZT detector through the depth sensitive technology（C/A value method）.Subsequently,the technology was used to correct the ¹³⁷Cs characteristic peak energy spectrum.After the correction,the energy resolution was increased from 4.20%to 2.65%@662ke V,which greatly improved the energy resolution of the detector,and the obvious improvement in terms of"low energy tailing"phenomenon has been made,verifying the feasibility and practicability of the deep sensitivity technique and its application in energy spectrum correction.3.We studied the portable energy spectrometer technology based on the hemispherical CZT detector.The energy spectrometer has a volume of 30×30×115mm³,a weight of 200g,an energy resolution of 2.0%@662ke V,and an energy response range of 30ke V～1.5Me V,the maximum count rate is 10000cps,power consumption is 800m W.Compared with commonly used scintillator detectors such as Na I and Cs I and HPGe semiconductor detectors,this spectrometer has the advantages of good portability,high energy resolution,and the ability to work normally at room temperature.At the same time,the portable energy spectrometer is suitable for environmental dose monitoring and nuclide identification energy and spectrum analysis of different radiation types in the environment.