Improving the Geometric Description of the sPHENIX Hadronic Calorimeter in GEANT4 for Accurate Jet Energy Measurements

The sPHENIX detector at the Relativistic Heavy Ion Collider (RHIC) includes tracking detectors, an electromagnetic calorimeter (EMCal), an inner hadronic calorimeter (HCal), and a solenoid magnet surrounded by an outer HCal. GEANT4 is used to study the hadronic energy deposited in the HCal by jets formed during 200 GeV p+p and Au+Au collisions. The outer HCAL geometry is quite complex, for example, the cryogenic services required to cool the super-conducting magnet requires a cut-out in a section of the outer HCal. The level of detail included in the simulation of the detector, specifically in the description of the chimney cutout, can affect the accuracy of the simulation of jets produced at sPHENIX. The description of the HCal geometry uses a geometry description markup language (GDML) implementation of the as-built CAD drawings of the detector which provides a highly realistic description of the detector geometry at the expense of increased computational time. This poster will present a comparison of a detailed description of the geometry from a GDML implementation of the CAD drawings to using simple GEANT4 shapes to approximate the geometry. The necessary detail in GEANT4 will be evaluated by comparing results of jet performance plots between the detailed geometry and a simplified model, to gauge if there are deviations and changes in the jet performance.