sPHENIX HCal discussion

["Lajoie, John G [PHYSA]" <lajoie AT iastate.edu>]

Hi Megan, Kristyn:

 

Very nice – just a few comments that I hope will help make the thrust of your presentation more clear.

 

Line 2: “… an inner hadronic …”

Line 3: I think you need to be a bit more specific here, what you study with G4 is the energy deposited by the jets in the HCAL. Something like “GEANT4 is used to study the hadronic energy deposited in the HCAL by jets formed during 200 GeV …”

Line 4: I would drop this line “While the EMCal and inner HCal are reasonably described in GEANT4 as cylindrical, the outer HCal geometry is more complex.” and combine with the following sentence. Replace it with “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 inner HCAL and EMCal geometry is every bit as complex as the outer HCAL, and is not represented by cylinders in the sPHENIX MC.

Line 8: drop “The use of uniformed shapes creates a discrepancy between the physical detector and what is depicted in GEANT4.”  You’ve already made this point with the previous sentence.

Line 8-9:  “The description of the HCal geometry in sPHENIX simulations 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.”

Line 10:  “…between the detailed geometry and a simplified model to …”

 

John

 

John Lajoie (he, him, his)

Harmon-Ye Professor of Physics

Iowa State University

 

(515) 294-6952

lajoie AT iastate.edu

 

From: sPHENIX-HCal-l <sphenix-hcal-l-bounces AT lists.bnl.gov> On Behalf Of Megan Connors via sPHENIX-HCal-l
Sent: Monday, July 31, 2023 4:01 PM
To: sphenix-hcal-l AT lists.bnl.gov; sphenix-jet-structure-l AT lists.bnl.gov
Cc: kspears4 AT student.gsu.edu
Subject: [Sphenix-hcal-l] CEU abstract GEANT4

 

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.