An analysis of side readouts of monolithic scintillation crystals

We have explored a method of using the side surfaces of a thin monolithic scintillation crystal for reading out scintillation photons. A Monte-Carlo simulation was carried out for an LYSO crystal of 50:8mmx50:8mmx3mm with 5 silicon photomultipliers attached on each of the four side surfaces. With 511 keV gamma-rays, X-Y spatial resolution of 2:10mm was predicted with an energy resolution of 9:0%. We also explored adding optical barriers to improve the X-Y spatial resolution, and an X-Y spatial resolution of 786um was predicted with an energy resolution of 9:2%. Multiple layers can be stacked together and readout channels can be combined. Depth-of- interaction information (DOI) can be directly read out. This method provides an attractive detector module design for positron emission tomography (PET).