Feasibility Study on Silicon Photomultiplier With Epitaxial Quenching Resistors as the Readout for PET Detectors

The silicon photomultiplier (SiPM) with epitaxial quenching resistors (EQR) is a novel SiPM technology currently under research and development. It has distinguished features of simple device structure, high fill factor, high microcell density, large dynamic range, and fast recovery time. In this paper, we report its latest developments aiming at positron emission tomography (PET) applications. The EQR type SiPM with active area of
$2.2~\hbox{mm} \times 2.2~\hbox{mm}$
demonstrated a peak PDE of 11.6% at 460 nm, PDE greater than 8.0% at 420 nm, temperature coefficient for breakdown voltage of 16 mV per
$^\circ {\rm C}$
, with the fill factor of 40% and microcell density as high as
$\sim 9000/\hbox{mm}^{2}$
. We measured a time resolution better than 357 ps FWHM and a 17.5% FWHM energy resolution at 511 keV by 1-to-1 coupling of the device with a
$2~\hbox{mm} \times 2~\hbox{mm} \times 10~\hbox{mm}$
lutetium yttrium oxyorthosilicate (LYSO) crystal without any preamplifiers. Those preliminary results show the potential of using such SiPM to build a high spatial resolution and high timing resolution PET system.