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Sub-pixel resolution in pixelated CdZnTe gamma ray detectors with different pixel sizes (0.5 mm to 1.72 mm) using a focused laser beam (Conference Presentation)

Paper Abstract

High-resolution position-sensing has been proposed to correct response non-uniformities in Cadmium Zinc Telluride (CZT) gamma ray detectors by virtually subdividing the area into small voxels and equalizing responses from each voxel. 3D pixelated detectors coupled with multichannel readout electronics are the most advanced type of CZT devices offering many options in signal processing and enhancing detector performance. The main hurdle in achieving high sub-pixel position resolution is the relatively low signal induced on the neighboring pixels because of the electrostatic shielding effect caused by the collecting pixel. In addition, to achieve high position sensitivity one should rely on time-correlated transient signals, which means that digitized output signals must be used. Previous results have shown the benefit of using a focused laser beam to study position resolution in 3D pixelated detectors. We present the results of our studies to measure the amplitude of the pixel signals so that these can be used to measure positions of the interaction points. This is done with the processing of digitized correlated time signals measured from several adjacent pixels taking into account rise-time and charge-sharing effects. In these measurements we used a focused pulsed laser to generate a 10-micron beam at one milliwatt (650-nm wavelength) over the detector surface while the collecting pixel was moved in cardinal directions. The results include measurements that present the benefits of combining conventional pixel geometry with digital pulse processing for the best approach in achieving sub-pixel position resolution with different pixel dimensions ranging from 0.5 mm to 1.72 mm.

Paper Details

Date Published: 19 September 2017
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Proc. SPIE 10392, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XIX, 103920V (19 September 2017); doi: 10.1117/12.2275429
Show Author Affiliations
Luis A. Ocampo Giraldo, The Pennsylvania State Univ. (United States)
Aleksey E. Bolotnikov, Brookhaven National Lab. (United States)
Giuseppe S. Camarda, Brookhaven National Lab. (United States)
Gianluigi De Geronimo, Brookhaven National Lab. (United States)
Rubi Gul, Brookhaven National Lab. (United States)
Jack Fried, Brookhaven National Lab. (United States)
Anwar Hossain, Brookhaven National Lab. (United States)
Kenan Unlu, The Pennsylvania State Univ. (United States)
Emerson Vernon, Brookhaven National Lab. (United States)
Ge Yang, Brookhaven National Lab. (United States)
Ralph B. James, Savannah River National Lab. (United States)


Published in SPIE Proceedings Vol. 10392:
Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XIX
Arnold Burger; Ralph B. James; Michael Fiederle; Larry Franks; Stephen A. Payne, Editor(s)

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