An SiPM based readout for the sPHENIX calorimeters

Conceived and constructed over a decade ago, the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory was designed to discover Quark-Gluon Plasma, QGP. Following up on the discovery of QGP, the PHENIX collaboration has embarked on a series of upgrades designed to explore the properties of QGP, with the next phase being sPHENIX. The sPHENIX upgrade replaces the current central arm spectrometer with a compact superconducting solenoid, electromagnetic and hadronic calorimetry optimized to study jets produced in p+p, p+A and A+A collisions at RHIC. The compact nature of the detector (r ~ 1m) means that the optical readout of the calorimetry will be in the vicinity of the of the magnetic field of the solenoid, which will require an optical readout immune to effects of magnetic fields. For sPHENIX, we have designed an optical readout system based on Silicon Photo-Multipliers (SiPMs) for both the electromagnetic and hadronic calorimeters. In this paper we will present the conceptual design of the readout system based on SiPMs and the results of preliminary studies of SiPM performance in context of the the sPHENIX readout requirements.