GEANT4 simulations for the Lund R 3 B prototype Douglas Di Julio Lund University, Lund, Sweden.
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Transcript of GEANT4 simulations for the Lund R 3 B prototype Douglas Di Julio Lund University, Lund, Sweden.
GEANT4 simulations for the Lund R3B prototype
Douglas Di Julio Lund University, Lund, Sweden
Outline
• TSL proton tests
• GEANT4 proton simulations
• Preliminary GEANT4 -ray simulations
Experimental tests at TSL
180 MeV Protons
1 mm thick 60x60 mm2 SSSDs
Prototype
Beam profile
• 180 MeV protons• Two-1mm thick SSSDs
– Beam positioning and electronic collimator• Goal: measure resolution of the crystals and to test gain corrected summing• Calibration: Cu Collimator
Beam spot ~40 mm2
Energy Resolution
Resolution measured with the LundR3B calorimeter
Compilation of energy resolution data
Gain Corrected Summing• At 180 MeV:
– 21% events lost to inelastic processes– 32% recovered from add back– 47% deposit full energy in single crystal
• At 300 MeV, no events deposit full energy, however 60% can be recovered by gain correct summing
GEANT4 simulations
Gain Corrected Summing• Gain corrected
summing with central, above and below crystals
• M=1 events centered around proton incident energy
• M>1 events contained in structure shifted to lower energies
GEANT4 Simulations
• Material: CsI and Mylar for foils
• Vacuum gap between crystals
10x30
130 mm
15x4
210x10
Gain Corrected Summing
• Binary Cascade model used
• Resolution: R = 5.15E1/2
Simulated Sum Spectrum
Gain Corrected Summing
Edep in crystal Edep in wrap
Sum
Detector resolutionswitched off
Gain Corrected Summing
• Reducing the foil thickness can reduce the effect
• Counteracts energy resolution presented earlier
• How does the reduced foil thickness effect light collection?
M=2 events
Preliminary -ray simulations
Resolution measured with CsI/APDElements, relation used in simulation
For -ray simulations:•Low energy package – Photoelectric, conversion, Rayleigh, and Compton Scattering•Low energy package for e-•Multiple scattering, ionisation, Bremsstrahlung, and annihilation (for e+)•Uniform irradiation of the full central crystal face
Preliminary -ray simulations1 MeVSum Spectrum15 crystals
6.1 MeVSum Spectrum15 crystals
Future work
• Compare simulation results with in-beam tests at the Lund Nuclear Microprobe
• Light collection properties– Light cross talk between crystals