This paper presents details of the design and performance of three prototype Scintisphere detectors for use in gamma-ray spectroscopy. In these detectors, spherical CsI(Tl) scintillation crystals, having diameters ranging from 3.4 cm (20 cm3) to 8.3 cm (300 cm3), were polished and packed in dry MgO powder. The scintillation light from the crystal was viewed using a single 1 × 1 cm2 silicon PIN diode. A low-noise preamplifier was also integrated within the detector housing. The measured noise level was equivalent to ∼800 electrons (FWHM). Such a configuration results in a relatively high light-collection efficiency. For example, in the 300 cm3 (8.3 cm diameter) detector, an average of ∼10 electron/hole pairs were generated for each keV deposited in the crystal. One of the key features of this detector design is that it minimizes the spatial variations in the light-collection efficiency throughout the detector. Compared with a standard 3-in NaI(Tl) scintillation counter, this leads to a much-improved energy resolution, particularly for photon energies above 1 MeV. The results presented in this paper clearly demonstrate that these spherical CsI-photodiode detectors could be used as an ideal replacement for the standard 3-in NaI(Tl) detectors in many applications.
- Spherical detector
- γ-ray spectroscopy
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering
- Electrical and Electronic Engineering