SiPM Testing and Sorting Simulation for the sPHENIX Collaboration

The sPHENIX collaboration studies heavy ion collisions in an effort to better understand the strong nuclear force. The collaboration has proposed a new detector to be built at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The electromagnetic and hadronic calorimeters will use approximately 100,000 silicon photomultipliers (SiPMs) to detect light from showers produced in the calorimeters by particles produced by the collisions. The SiPMs will be supplied by Hamamatsu, model S12572-015P. There will be four SiPMs per calorimeter tower, all operated at the same voltage. The SiPMs need to be sorted so each calorimeter tower has balanced gain. One of the objectives of my research was to test the gain and operating voltage of an SiPM by measuring single photoelectron peaks shift with bias voltage. The second objective of my research was to develop a method to sort the tested SiPMs with similar gain into groups of four. In this poster I will give details of the test stand, show gain measurements, and the results of the simulation used to develop the sorting method.