Hybrid Pixel-Waveform Waveform (HPWF) Enabled CdTe Detectors for Small Animal Gamma Gamma-Ray Imaging Applications
Abstract: This paper presents the design and preliminary evaluation of small-pixel small CdTe gamma ray detectors equipped with a hybrid pixel pixel-waveform waveform (HPWF) readout system for gamma ray imaging applications with additional discussion on CZT due to its similarity. The HPWF readout system utilizes a pixelated anode readout circuitry which is designed ned to only provide the pixel address. This readout circuitry works in coincidence with a high high-speed speed digitizer to sample the cathode waveform which provides the energy, timing, and depth depth-of-interaction interaction (DOI) information. This work focuses on the developed and experimentally evaluated prototype HPWF-CdTe CdTe detectors with a custom CMOS pixel pixel-ASIC ASIC to readout small anode pixels of 350 Îźm in size, and a discrete waveform sampling circuitry to digitize the signal waveform induced on the large cathode. The intrinsic timing, energy, and spatial resolution were experimentally evaluated in this paper in conjunction with methods for depth of interaction (DOI) partitioning of the CdTe crystal. While the experimental studies discussed in this paper are primarily for evaluating evalua HPWF detectors for small animal PET imaging, these detectors could find their applications for ultrahigh-resolution resolution SPECT and other imaging modalities.