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Energy-loss correction in charge sharing events for improved performance of pixellated compound semiconductors
- Source :
- Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 940:142-151
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- The sharing of charge between multiple pixels can significantly degrade the energy resolution of small pixelated compound semiconductor detectors. This paper describes an energy calibration and reconstruction technique to correct for absorbed energy that is split over two neighbouring pixels, defined as bipixel events. Results were obtained with a 1 mm thick CdTe detector with 250 µm pixel pitch and an inter-pixel spacing of 50 µm, using the STFC HEXITEC ASIC. The proportion of charge sharing events was found to be 54% for photons at 59.5 keV when applying a noise threshold of 3 keV. Across the energy range investigated, bipixels were the predominant shared event type and the absolute fraction of shared events was found to be dependent on the noise threshold used. The reconstruction technique described reduces the degradation of energy resolution due to charge sharing in bipixel events compared to simple charge sharing summing techniques. This improved counting efficiency compared to using only isolated events and improved energy resolution compared to pixel addition techniques. When only isolated pixels were included, a FWHM energy resolution of 1.42 keV at 140.5 keV was achievable; inclusion of bipixel events using pixel addition results in an energy resolution of 3.33 keV whereas the reconstruction technique described here results in an energy resolution of 2.14 keV. When bipixel events are combined with single pixel events, the number of counts within the 140.5 keV photopeak of 99mTc increased by over 100%.
- Subjects :
- Physics
0303 health sciences
Nuclear and High Energy Physics
Range (particle radiation)
Photon
Pixel
Physics::Instrumentation and Detectors
business.industry
030303 biophysics
Detector
Counting efficiency
Dot pitch
030218 nuclear medicine & medical imaging
Charge sharing
03 medical and health sciences
0302 clinical medicine
Optics
business
Instrumentation
Energy (signal processing)
Subjects
Details
- ISSN :
- 01689002
- Volume :
- 940
- Database :
- OpenAIRE
- Journal :
- Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
- Accession number :
- edsair.doi...........e4518f425d666a49a81e6a22f8be9ee4