Pixellated thallium bromide detectors for gamma-ray spectroscopy and imaging

T. Onodera, K. Hitomi, T. Shoji, Y. Hiratate

Research output: Contribution to journalConference articlepeer-review

33 Citations (Scopus)

Abstract

Recently, pixellated semiconductor detectors exhibit high-energy resolution, which have been studied actively and fabricated from CdTe, CZT and HgI2. Thallium bromide (TlBr) is a compound semiconductor characterized with its high atomic numbers (Tl=81, Br=35) and high density (7.56g/cm3). Thus, TlBr exhibits higher photon stopping power than other semiconductor materials used for radiation detector fabrication such as CdTe, CZT and HgI2. The wide band gap of TlBr (2.68eV) permits the detectors low-noise operation at around room temperature. Our studies made an effort to fabricate pixellated TlBr detectors had sufficient detection efficiency and good charge collection efficiency. In this study, pixellated TlBr detectors were fabricated from the crystals purified by the multipass zone-refining method and grown by the horizontal traveling molten zone (TMZ) method. The TlBr detector has a continuous cathode over one crystal surface and 3×3 pixellated anodes (0.57×0.57mm2 each) surrounded by a guard ring on the opposite surface. The electrodes were realized by vacuum evaporation of palladium through a shadow mask. Typical thickness of the detector was 2mm. Spectrometric performance of the TlBr detectors was tested by irradiating them with 241Am (59.5keV), 57Co (122keV) and 137Cs (662keV) gamma-ray sources at temperature of -20°C. Energy resolutions (FWHM) were measured to be 4.0, 6.0 and 9.7keV for 59.5, 122 and 662keV gamma-rays, respectively.

Original languageEnglish
Pages (from-to)199-204
Number of pages6
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume525
Issue number1-2
DOIs
Publication statusPublished - 2004 Jun 1
EventProceedings of the International Conference on Imaging Technique - Stockholm, Sweden
Duration: 2003 Jun 242003 Jun 27

Keywords

  • Imaging detector
  • Pixellated detector
  • Thallium bromide
  • X- and γ-ray detector

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

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