Feasibility study of a position-sensitive hemispheric CZT radiation detector (Conference Presentation)

In this work, we reconfigured the design of the electrodes, incorporating the high-granularity position-sensitive 3D concept into a larger geometrical form factor, e.g., hemispheric detectors, to improve the uniformity of charge collection and the energy resolution. We designed and fabricated new position-sensitive hemispheric detectors and measured the pulse-height spectra and acquired charge transport data and other electrical measurements with different sealed radioactive sources before and after modifying the design, and compared their performance to identify the optimum configuration. We then applied charge-loss corrections by utilizing the x-y-z positional information from the charge-sensing pads for each event. Based on our simulations and experimental data, we optimized a new configuration for our position-sensitive hemispheric detectors that can effectively be fabricated as large as 20x20x15-mm3 size. Furthermore, our simulation suggests that we can achieve an energy resolution of <1% (FWHM) at 662 keV from even 10x10x5 mm3 sized position-sensitive hemispheric detectors using average-grade CZT crystals.