CHARACTERISTICS OF THE NEW YALO(3) - CE COMPARED WITH BGO AND GSO

The characteristics of YAlO3:Ce used as a fast scintillation detector with high density (5.35 gm/cm3) and high light yield were investigated and compared with other scintillation materials. The decay of the scintillation light could be described by the sum of two exponentials with decay constants of 31 ns and 246 ns, contributing 98% and 2% to the total light yield, respectively. The light yield of 19700 photons/MeV was measured by comparing the number of photoelectrons produced in YAlO and in BGO under the same conditions. The energy resolution at a gamma ray energy of 511 keV was 6.7% for a 4.0 x 8.0 x 25.0 mm3 sample. The FWHM of a timing measurement using two YAlO crystals detecting annihilation quanta (with 200 keV threshold) was 1.1 ns. Monte Carlo simulations showed that the crystal depth for the absorption of 90% of 511 keV gamma quanta is 51.8 mm in YAlO (compared with 25.2 mm in BGO).