Scintillation properties of LuYAP and LYSO crystals measured with MiniACCOS, an automatic crystal quality control system

The Crystal Clear Collaboration has built a small animal PET, the ClearPETtrade and is now working on a dedicated PET for mammography, the ClearPEMtrade. The gamma-ray detectors in these machines consist of matrices of small scintillation crystals coupled to photo detectors. In all the detectors for the ClearPEMtrade about 6000 LYSO (2times2times20 mm³) crystals are used while for the ClearPETtrade the number is around 5000 LYSO and the same amount of LuYAP crystals with a dimension of 2times2times10 mm³ in a phoswich combination. An automatic system to measure the light yield, decay time and energy resolution of those L(Y)SO and Lu(Y)AP pixels of different sizes on a fast basis (around 500 per day) was constructed at CERN, the MiniACCOS (mini automatic crystal quality control system). This paper offers a short description of the MiniACCOS system and presents first results of crystal measurements of about 10000 LYSO and LuYAP pixels and compares them to previously produced batches of LuYAP crystals produced by two different growth methods