Readout of LYSO using a new silicon photodetector for positron emission tomography

This article focuses on the characterisation of three versions of a custom designed silicon photodetector using nuclear spectroscopy techniques. Room temperature gamma ray spectroscopy experiments have been performed using an LYSO excited by ¹³⁷Cs and ²²Na sources and read out by the new photodiodes. We have measured an energy resolution of 13.1% FWHM for the 511 keV gamma rays from a ²²Na source and 11.2% FWHM for the 662 keV gamma rays from a ¹³⁷Cs source. This is one of the best ever-reported energy resolutions for a lutetium based scintillator crystal read out by a silicon photodetector.