HCAL Digitization Rick Wilkinson

Program Flow CaloHitResponse CaloSamples (analog signal) HcalElectronicsSim HBHEDataFrame (or HF, or HO) SimHits DetId= , 10samples 0:0 1: : : : : : : : : (HB 1,1,1) 10 samples 4 presamples ADC=4, capid=1, DV ADC=6, capid=2, DV ADC=8, capid=3, DV ADC=5, capid=0, DV ADC=58, capid=1, DV ADC=54, capid=2, DV ADC=33, capid=3, DV ADC=21, capid=0, DV ADC=14, capid=1, DV ADC=9, capid=2, DV Energy GeV Tof ns Geant track #0

SimHits One SimHit is created for each: Generator particle Detector Unit Nanosecond of shower development A typical 100 GeV charged pion will have: 30 detector cells 75 SimHits (~1/4 with long time of flight)

CaloHitResponse HcalHitCorrection CaloSimParameterMap CaloVShape ● Do Time Slew ● Photostatistics ● Shaping ● Superimpose Delay 3 ns for big hits, up to 10 ns for small hits 14 ns peak in HB, HE, HO 2 ns peak in HF 17 photoelectrons per incoming GeV (HF hits already in p.e.) FOR EACH HIT:

Time Slew Observed effect: small signals arrive later than large ones Implementation: Delay is applied to each SimHit, based on expected signal charge Exaggerates the effect: real signal can be a sum of many SimHits Tuning may be needed HCAL: ~6 fC/GeV HF: ~2 fC/GeV HO uses “Slow” Others use “medium”

Calibration Databases ● Digitization is designed to use calibration & condition interfaces ● Gains & gain widths ● Pedestals & pedestal widths ● Digi encoding ● Trigger primitive encoding & compression ● For now, I just get hardcoded numbers, through the DB interface ● Datasets will always know what conditions were used to make them ● Allows a more realistic simulation of the real detector ● Hot channels will be hot, & noisy channels will be noisy. ● Each simulated event could be assigned to an actual run. ● Allows a more realistic simulation of calibrations ● Can simulate with one set of constants ● Blindly try to determine calibrations ● Reconstruct with derived calibrations

HcalElectronicsSim ● Convert from photoelectrons to fC ● Calculate from Fedor's calibrations: ● /- 0 GeV/fC (HB, HE, HO) ● /- 0 GeV/fC (HF) ● Result is 0.32 fC/pe (HB, HE, HO) ● Amplification of 2000x. ● HF: 1 fC/pe for short fibers, 0.72 fC/pe for long ● ORCA uses 2.3 pe/fC ● Apply pedestals & pedestal noise ● Again, retrieved from DB interface ● / fC (HB,HE,HO) ● / fC (HF) ● Use Fedor's encoding Service FOR EACH Analog signal:

Trigger Primitives ● Tower Mapping done through geometry service ● One-to-one in barrel ● Energy split between two trigger towers in double-wide  endcap regions ● 6 cells to one tower in HF ● Energy summed by TPGCoder conditions object ● 125 MeV per ADC ● Output is HcalTriggerPrimitiveDigi ● compressed using a HcalTPGTranscoder conditions object

Still Missing: ● Zero suppression