Research On Scattering Detection Technology Based On Discrimination Grade CdZnTe Detector

CdZnTe has some excellent characteristics such as high atomic number, high density,high resistance and so on, so that it can work at room temperature. Compared with the Si and Ge detectors, the CdZnTe detector has a special status in the domain of ? and ?-ray detection.First, this thesis sums up the principles, characteristics, application and development of Compton scattering detection technology, and the structure of Compton scattering detection system designed in this thesis, and CdZnTe detectors and nuclear electronics magnifying circuits which the system used are introduced simply.Secondly, FPGA high-speed data acquisition system connected after nuclear electronics magnifying circuit is also introduced. The data acquisition system uses multi-level structured,modular design. Each module of this system is programmed by the Verilog HDL language.The interface uses DLL(Dynamic Link Library) to achieve communication between PC and serial port under VC++ environment. According to receive different control commands sent by PC, FPGA sets corresponding time for 54 channels parallel data acquisition.And then, programming threshold value discrimination system based on FPGA is introduced. The system reads Compton scattering spectrum unscrambling information and sends it to FPGA module, which drives 8 chips of DACs(10bits). FPGA reads control commands from PC by serial port, and then it rapidly drives DACs to give accurate threshold values.Finally, spectrum unscrambling algorithm about multi-angle Compton scattering is systematically expounded. By learning the traditional spectrum unscrambling algorithm and integrating with detection characteristics of Compton scattering detection system, the spectrum unscrambling algorithm is designed based on full spectrum least squares algorithm.According to add some empirical peak locate criterions in this spectrum unscrambling, the actual spectrum unscrambling has a good result.