sPHENIX HCal discussion

[Megan Connors <meganeconnors AT gmail.com>]

Dear all,

GSU student, Kristyn Spears, filled in Marzia's form last week but I wanted to make sure everyone had a chance to comment on her abstract for the CEU program. Please let us know if you have any comments on her abstract copied below. The CEU submission deadline is Wed, Aug 2.

Thanks,

-Megan

Title: "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), inner hadronic calorimeter (HCal), and a solenoid magnet surrounded by an outer HCal. GEANT4 is used to study the hadronic energy of jets formed during 200 GeV p+p and Au+Au collisions, and reconstruct jets with simulated sPHENIX calorimeters. While the EMCal and inner HCal are reasonably described in GEANT4 as cylindrical, the outer HCal geometry is more complex. A chimney-like structure is required to cool the super-conducting magnet which cuts into 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 simulations of jets produced at sPHENIX. The use of uniformed shapes creates a discrepancy between the physical detector and what is depicted in GEANT4. An alternative description of the HCal geometry uses a geometry description markup language (GDML) implementation of CAD drawings of the detector which increases the CPU time to generate sufficient statistical precision in the simulation. 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 simple and detailed geometry, to gauge if there are deviations and changes in the jet performance.