Presentation + Paper
4 October 2022 Improved performance and longevity of large volume thallium bromide devices
Author Affiliations +
Abstract
Thallium bromide (TlBr) is a promising material for room temperature gamma radiation detection due to its high density, high atomic number, and wide bandgap. Additionally, TlBr has a cubic crystal structure and melts congruently at a relatively low temperature. Advances in material purification, crystal growth and device processing have led to improved material quality including a significant increase in the mobility-lifetime product of electrons in TlBr. This has enabled single carrier collection devices with thicknesses of 1 cm and beyond. The arrays have been flip-chip bonded to carrier boards using a low temperature curing conductive polymer. In this paper we report on results from planar and pixelated devices. Planar TlBr devices with dimensions of 12 mm × 12 mm × 7 mm exhibit an energy resolution ranging from 3% to 5% FWHM at 662 keV when using a shaping time of 2 s. The energy resolution in planar devices improves with a reduction of the shaping timing consistent with the expected amelioration of the depth dependence. The 1-cm thick pixelated arrays, with a pitch of 1.72 mm, produce an energy resolution in the anode spectrum ranging from 1.8% to 4.4%, without applying depth corrections. This work presents spectra from a selected pixel for 133Ba and 57Co irradiation. Measurements of the room-temperature stability of the planar and pixelated detectors show that the position of the 662-keV photopeak is stable over a period of ~200 days, but the shape of the photopeak in the anode spectra exhibits small changes. These detectors show promise for applications in radio-isotope identification devices and for medical imaging.
Conference Presentation
© (2022) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
H. Kim, L. Cirignano, J. F. Christian, A. Kargar, Y. Ogorodnik, S. Kim, M. Breen, M. R. Squillante, and K. Shah "Improved performance and longevity of large volume thallium bromide devices", Proc. SPIE 12241, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XXIV, 1224106 (4 October 2022); https://doi.org/10.1117/12.2635925
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KEYWORDS
Sensors

Cesium

Thallium

Gamma radiation

Semiconductors

Amplifiers

Sensor performance

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