High Efficiency CsI(Tl)/HgI2 Gamma Ray Spectrometers

Y. J. Wang, B. E. Patt, J. S. Iwanczyk, S. R. Cherry, Y. Shao

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

CsI(Tl)/HgI2 gamma-ray spectrometers have been constructed using 0.5” diameter detectors which show excellent energy resolution: 4.58% FWHM for 662 keV 137Cs gamma-ray photons [1]. Further efforts have been focused on optimization of larger size (≥1” diameter) detector structures and improvement of low noise electronics. In order to take full advantage of scintillation detectors for high energy gamma-rays, larger scintillators are always preferred for their higher detection efficiencies. However, the larger capacitance and higher dark current caused by the larger size of the detector could result in a higher FWHM resolution. Also, the increased probability of including nonuniformities in larger pieces of crystals makes it more difficult to obtain the high resolutions one obtains from small detectors. Thus for very large volume scintillators, it may necessary to employ a photodiode (PD) with a sensitive area smaller than the cross-section of the scintillator. Monte Carlo simulations of the light collection for various tapered scintillator/PD configuration were performed in order to find those geometries which resulted in the best light collection. According to the simulation results, scintillators with the most favorable geometry, the conical frustum, have been fabricated and evaluated. The response of a large conical frustum (top-2”, bottom-1”, 2” high) CsI(Tl) scintillator coupled with a 1” HgI2 PD was measured. The energy resolution of the 662 keV peak was 5.57%. The spectrum shows much higher detection efficiency than those from smaller scintillators, i.e., much higher peak-to-Compton ratio in the spectrum.

Original languageEnglish (US)
Pages (from-to)601-605
Number of pages5
JournalIEEE Transactions on Nuclear Science
Volume42
Issue number4
DOIs
StatePublished - Jan 1 1995

Fingerprint

Gamma ray spectrometers
gamma ray spectrometers
Phosphors
scintillation counters
frustums
Photodiodes
detectors
Detectors
photodiodes
Full width at half maximum
Gamma rays
gamma rays
Scintillation counters
Geometry
Dark currents
high resolution
geometry
dark current
nonuniformity
low noise

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Electrical and Electronic Engineering
  • Nuclear and High Energy Physics

Cite this

High Efficiency CsI(Tl)/HgI2 Gamma Ray Spectrometers. / Wang, Y. J.; Patt, B. E.; Iwanczyk, J. S.; Cherry, S. R.; Shao, Y.

In: IEEE Transactions on Nuclear Science, Vol. 42, No. 4, 01.01.1995, p. 601-605.

Research output: Contribution to journalArticle

Wang, Y. J. ; Patt, B. E. ; Iwanczyk, J. S. ; Cherry, S. R. ; Shao, Y. / High Efficiency CsI(Tl)/HgI2 Gamma Ray Spectrometers. In: IEEE Transactions on Nuclear Science. 1995 ; Vol. 42, No. 4. pp. 601-605.
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