sPHENIX Electromagnetic Calorimeter Block Evaluation

sPHENIX is a detector under construction at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, and will begin collecting data in February of 2023. By the collision of heavy nuclei, RHIC is capable of creating a quark-gluon plasma (QGP), a hot, dense state of unconfined quarks and gluons. Jets, collimated sprays of energetic particles, serve as important probes of the plasma, as they have been modified relative to jets in baseline proton-proton collisions because their parent partons have lost energy to the QGP. In order to provide precision measurements of jets and jet energy loss, sPHENIX has both electromagnetic and hadronic calorimetry at midrapidity. The electromagnetic calorimeter (EMCal) is the innermost calorimeter system and is composed of blocks made of tungsten powder and scintillating fibers. Particles will embed energy into the calorimeter blocks, and the fibers collect that energy in the form of light, which is then read out by a silicon photomultiplier (SiPM). We report a study of the EMCal's energy response to single photons measured in an sPHENIX-based GEANT4 simulation. We have evaluated the average response, as well as how the response varies as a function of where a photon lands in the EMCal. Inefficiencies in light collection near the edges of the towers are seen and corrected for, using a procedure developed during beam tests of EMCal prototypes. This poster presents the results of these studies.