A Readout Electronic System for a 3D Position-Sensitive CdZnTe Gamma-Ray Spectrometer Based on the CPRE10-32 Readout ASIC

Semiconductor detectors are widely used in x-ray and γ-ray detection. A series of semiconductor materials, Si, Ge, GaAs, HgI2, CdZnTe, etc. are mostly used. Due to the physical properties of CdZnTe, nuclear detection and imaging instruments based on CdZnTe detectors have been used in the fields of homeland security, medical imaging, astronomical observation, and physical research. As a room-temperature semiconductor material, CdZnTe can be used to design imaging and spectroscopic devices in a small size. Extensive research on CdZnTe detectors has led to different types of detectors being designed, among which pixelated detectors are widely used due to the high energy resolution and the capability of acquiring the 3D position information. The applications of the pixelated detectors are spectral detection, Compton imaging and coded aperture imaging. In order to get the excellent energy spectrum, a low noise readout electronics is required, and the correction of the spectrum based on the depth of interaction (DOI) is also important. To acquire the DOI information inside the CdZnTe detector, there are two ways which are commonly used. One is using the cathode/anode ratio. However, it can only be conducted in single-pixel interaction events. By acquiring the time information between the cathode and anode, the other method called electron drift time can be used to determine the DOI information of several-pixel interaction events. To realize the Compton imaging, the energy data and the DOI data are necessary which has been mentioned before. The coded aperture imaging demands a programmable energy threshold. Considering all demands above, a readout electronic system having all these functions is needed for the implement of pixelated 3D position-sensitive CdZnTe spectrometer. As the critical part of the electronic system, the readout application specific integrated circuit (ASIC) called CPRE10-32 was designed for multi-channel detectors as CdZnTe spectrometer is. Based on the CPRE10-32 readout ASIC, the readout electronic system can be designed. Within this chapter, a detailed description of the readout electronic system will be provided. The performance of the electronic system will also be provided including electronic characterization, spectral characterization and the spectral correction using the DOI data.