PowerPoint

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HCal Simulation with Geant4
3/31/2008M. Konno
1. Setup
200 cm (Y)
200 cm (Z)
50 cm (X)(75 cm)
Absorber:(Pb or Fe)
Scintillator
- 50 layers 1 layer = 1.0 cm (1.5 cm)
Particle: + (Ein = 0.5-100 GeV)

Processes: - Decays - EM interaction - Hadronic interaction (Model: LHEP_BERT)

Items: - Efficiency - Energy loss (, resolution) - Shower profile (transverse)

2. Particle Shot
Single particle (+, Ein = 10 GeV)
(Absorber: Fe, 12 mm)

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3. Energy loss in calorimeter
(Absorber: Fe, 12 mm)
Lower tail seen
(same data in log scale)

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4. Efficiency (for shower)
~85 % for 7 mm
~95 % for 12 mm

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5. Energy loss (Eloss>50MeV)
* Secondary particles flow out?

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6. Energy resolution (RMS/Mean, Eloss>50MeV)
* Only small fraction of particle energy measured. Its not the total energy.

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7-1. Shower profile - dE/dx vs. x
(Absorber: Pb, 7mm)
(Absorber: Fe, 7 mm)
* The dE/dx distributions are different between Pb and Fe.
(beam direction: x)

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7-2. Shower profile - dE/dx vs. x
(Absorber: Pb, 12 mm)
(Absorber: Fe, 12 mm)
* The dE/dx distributions are different between Pb and Fe.
(beam direction: x)

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8-1. Shower profile - dE/dr vs. r
(Absorber: Pb, 7mm)
(Absorber: Fe, 7 mm)

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8-2. Shower profile - dE/dr vs. r
(Absorber: Pb, 12 mm)
(Absorber: Fe, 12 mm)

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9-1. Shower profile R vs. Ein
The radius not changing much with Ein The energy loss is centered (In other words, a long tail seen around the center) R(Fe) < R(Pb)

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9-2. Shower profile R vs. Ein
The radius not changing much with Ein The energy loss is centered (In other words, a long tail seen around the center) R(Fe) < R(Pb)

10. Summary
The energy loss (, E) and efficiency are not so different between two absorbers Pb and Fe.

Efficiency: ~85% for absorber length = 35 cm (0.7 cm x 50 layers) Efficiency: ~95% for absorber length = 60 cm (1.2 cm x 50 layers)

R80(Fe, 12mm): ~12 cm, R80(Pb, 12mm): ~21 cm R(Fe) < R(Pb)
- Put EMCal in front of HCal- Introduce the photon detection efficiency Study the segmentation in YZ plane with PYTHIA jet information as Pb+Pb collisions Optimize the materials and geometry parameters to fit in ALICE detector Try to use other hadronic models
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