The performance of the sPHENIX prototype calorimeter readout electronics

The PHENIX collaboration has proposed a major upgrade, sPHENIX, to probe the nature of the Quark-Gluon Plasma, QGP, by studying jets produced in p+p, p+A, and A+A collisions at RHIC. The sPHENIX detector consists of a super-conducting solenoid, electromagnetic and hadronic calorimetry, and central tracking optimized for jet studies. The compact nature of the detector (r ~ 2.5m) 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 MultiPixel Photon Counters (MPPCs) for both the electromagnetic and hadronic calorimeters. As part of the design stage for sPHENIX, prototype electromagnetic and hadronic calorimeters with an MPPC based front end were built for evaluation as part of the Fermi National Laboratory Test Beam Experiment T-1044. In this paper we will present the design of the readout system based on MPPCs and the performance of the electronics in the test beam.