ECAL and HCAL Simulation Status
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Transcript ECAL and HCAL Simulation Status
ECAL and HCAL Simulation
Status
Rick Wilkinson
Fabio Cossutti
Simulation
Sim Hit: One ns of energy deposit in an
active volume
Done by GEANT4 (Sunanda Banerjee)
Depends strongly on geometry modeling
ECAL (Paolo Meridiani)
HCAL (Jeremy Mans)
Digitization
Digitization includes: pulse shape, pileup,
amplification, noise, ADC encoding, trig prims,
zero suppression
CMSSW Digitization has details not in ORCA
Common framework for all systems (Wilkinson)
ECAL (Cossutti, P. Govoni, Wilkinson)
HCAL (Fedor Ratnikov, Wilkinson)
Preshower (Chia-Ming Kuo)
Digitization using Calibration?
Allows added realism
Make hot channels hot, noisy channels noisy
Allows blind test of calibration techniques
Simulate the data with one set of constants
Use derived calibration for reconstruction
Noises
Pedestal
ECAL
Barrel
200 ADC
ECAL
Endcap
200 ADC
HCAL
HF
Pedestal
width
1.26 ADC
(40 MeV)
Gain Width
0.3 %
Rear non-uniformity
Front done in OSCAR
2.87 ADC 0.3 %
(150 MeV)
5 ADC
0.56 ADC 0
(0.75 GeV) (0.1 GeV)
2 ADC
0.3 ADC
0
(0.75 GeV) (0.14 GeV)
Photostatistics
Photoelectrons / GeV
1 / sqrt(N)
ECAL Barrel
2250
2.1% / sqrt(E)
ECAL Endcap
1800
2.4% / sqrt(E)
Photoelectrons / GeV
Sampling Frac.
HCAL (HB)
17
117
HCAL (HE)
17
117
HCAL (HO)
18.4
217
HCAL (HF1)
2.84
1
HCAL (HF2)
2.09
1
178
ECAL Digitization: Details
(Fabio Cossutti)
Gain Switching (including hysteresis)
Calibration Interface (Shahram Rahatlou)
No database access yet, just interface
Uses gain ratios, pedestals, & widths
Correlated Noise
Implemented with a global correlation matrix
Currently a unit matrix
HCAL Digitization: Details
Layer 0: Weighting done by GEANT4 (Banerjee)
Calibration Interface (Fedor Ratnikov)
Time Slew (Jeremy Mans)
Fetch pedestals, gains, & noise
For each of four capacitors in channel
Small signals delayed by ~10 ns
Correlated Noise
Effect is big in HCAL (Michal Szleper)
Not simulated, but infrastructure exists
Trig Prims
ECAL Trig Prims (Ursula Berthon)
HCAL Trig Prims (Jeremy Mans)
Zero Suppression
ECAL Selective Readout (Philippe Gras)
Trig prim > 5 GeV: read all 25x25 crystals
Trig prim > 2.5 GeV: read 5x5 crystals
Otherwise
HCAL Zero Suppression (Jeremy Mans)
90 MeV threshold in barrel
450 MeV in endcap
Pedestal-subtracted amplitudes
Can store both suppressed & unsuppressed digis
Validation
ECAL
Hits (Xingtao Huang)
Digis (F. Cossutti)
RecHits (Chiara Rovelli)
•30 GeV photons
•400 GeV photons
•60 GeV pions
•Neutrinos (for noise)
HCAL
•100 GeV Pions
•Hits (Salavat Abdullin)
•Digis (Dmitri Konstantinov)
ECAL Simulation Plans
New Geometry (Brian Heltsley)
Handles material behind the crystals better
Important for HCAL
Study shower shape
~1% discrepancy, maybe Cerenkov
Energy deposit inside APD