Research On The Gamma Ray Spectral Response Characteristics And Relevant Spectral Analysis Methods Of Cadmium Zinc Telluride (CdZnTe) Detector

Gamma-ray (γ) energy spectra measurement and analysis has been the key technique widely used in nuclear technologies and nuclear monitoring. The advent of room temperature operated Cadmium Zinc Telluride (CdZnTe, CZT) semiconductor detectors shows promise for designing high resolution portableγ-spectrometers. In recent years, the worldwide effort to fight against nuclear and radiation terrorism has caused the urgent demand for CZTγ-spectrometers. Therefore, the study on CZTγ-spectrometers has attracted a lot of researchers from the world. This dissertation topic is proposed under the critical demand for portableγ-spectrometers from the Chinese Chemical Defense Army to fight against terrorism. This research focuses on studying the CZTγdetector characteristics for detector type selection, and solving the corresponding spectra analysis problems.This dissertation makes the following four major contributions:(1) Experimentation and Monte Carlo simulation are conducted to investigate thoroughly theγspectra response characteristics of CZT detectors, which include energy resolution, detection efficiency and angle response. The experimental and simulated results match each other closely. The results show that CZT detectors can be applied for radionuclide identification for antiterrorism.(2) CZTγspectra usually have the following two disadvantages: serious statistical fluctuation and peak shape with a low energy tail. These characteristics present an obstacle for data analysis. In order to solve this problem, a set of data processing methods are utilized, including low band filtering, smoothing and peak seeking using the wavelet analysis method, and peak fitting using a complementary error fitting function. All these methods work efficiently.(3) A novel idea reconstructingγspectra using the Direct Demodulation (DD) method is proposed because of the still limited energy resolution of CZT spectra. The energy resolution of reconstructedγspectra is greatly improved, making it easier to find peaks and to distinguish the overlapped peaks. This shows promise for...