ecal simulation report brian heltsley simulation mtg 07 june 2010
DESCRIPTION
Ecal Simulation Report Brian Heltsley Simulation Mtg 07 June 2010. Recent Release Activity. Bugs in APD digitization described last time fixed & published in 38X Correctly redigitized MinBias-with-APD MC sample examined more closely Ecal Alignment for Reco to be activated. - PowerPoint PPT PresentationTRANSCRIPT
B. Heltsley Simulation Mtg - 07 Jun 20101
Ecal
Simulation
ReportBrian Heltsley
Simulation Mtg 07 June 2010
Recent Release ActivityBugs in APD digitization described last time fixed & published in 38X
Correctly redigitized MinBias-with-APD MC sample examined more closely
Ecal Alignment for Reco to be activated
B. Heltsley Simulation Mtg - 07 Jun 20102
Ecal Alignment NewsES Alignment studied
B. Heltsley Simulation Mtg - 07 Jun 20103
More on alignmentEgamma group noticed EE misalignment & reduced efficiency for endcap electrons
ES studies indicate relative EE-ES alignment is near-ideal
Egamma studies show similar-sized offsets
We decided to ‘turn on’ Ecal alignment
B. Heltsley Simulation Mtg - 07 Jun 20104
Alignment validationTried feeding in fake <1cm misalignments for EB, EE, ES via a TestProducer– Ran standard geometry self-consistency diagnostics. Oops!
• All three Ecal geometry classes had some built-in assumptions of perfect geometry
– These codes >5 years old
• getClosestCell( GlobalPoint& ) broken!• getCells( GlobalPoint&, double ) broken!
• Finally finished fixing these last week
• Changes published for 38X
DB Payloads with ES, EE alignments created– Being tested in a re-Reco by Egamma, ES groups
Also zero-alignment payload for MC Reco
B. Heltsley Simulation Mtg - 07 Jun 20105
Study of APD-MC Re-Digi
B. Heltsley Simulation Mtg - 07 Jun 20106
Number
B. Heltsley Simulation Mtg - 07 Jun 20107
Energy
B. Heltsley Simulation Mtg - 07 Jun 20108
APD energies probably a bit too high
E4/E1
B. Heltsley Simulation Mtg - 07 Jun 20109
Too many spikes!
Timing
B. Heltsley Simulation Mtg - 07 Jun 201010
APD Simulation Conclusions
Many qualitative features of the data which were previously completely missing from simulation are now surprisingly well-modeled
Need to move APD pulse back by 4-5 ns – Happens at digitization (parameter)
Probably need to reduce APD energy factors (~20%?) to retune spectrum & number
That MC sample did not have latest geometry with increased epoxy thickness– Iterate once more with 38X?
Planning for making APD geometry the default in 38X (any reason not to?)
B. Heltsley Simulation Mtg - 07 Jun 201011
Other Sim changes in progress(unchanged since last time)
Test containment factor– Sets overall MC energy normalization for EB & EE separately by
looking at simulated single 50 GeV photons– Not sure if GEANT has changed since this was updated
Change from fixed, uniform single-sample ADC noise to measured channel-by-channel values? – Can test with only a cfg change. Who/when ?
Correlation matrix for ES (which has 3 time samples)– Ming & I are examining this– Would be much more efficient than current CPU & memory-
intensive so-called “fast” method which tries to account for some of the correlations (ironically, with slower code)
B. Heltsley Simulation Mtg - 07 Jun 201012
Simulation Housekeeping(Unchanged since last time)
In progress– Reform digitized hit response handline
• Has same problem as analog version, too many new ‘s & delete’s
– Add ES digi creation to EB/EE templatized version, if possible– Inefficient ES Digi object (collection of std::vector<int> )
• Should look more like EB & EE Digi objects (long optimized)
• F. Ferri & P. Gras agree
• Migration would have to be carefully orchestrated
B. Heltsley Simulation Mtg - 07 Jun 201013
Backup slides
B. Heltsley Simulation Mtg - 07 Jun 201014
APD Simulation3rd generation geometry introduced– Input from Q. Ingram & I. Musienko
– Epoxy layer about twice as thick as in 2G APD geometry (which was 200 m)
– Further APD measurements could alter details
APD DigitizationTag set in 3_7_0_pre1 that allows it
Choose APD geometry w/1 or 2 layers
APD digitization either added to crystal digis &/or separately (as an “MC truth”), controllable via cfg.py parameter
APD layer-gains controllable via cfg.py
What test(s) & validation(s) are required to use as default?
B. Heltsley Simulation Mtg - 07 Jun 201015
The Real Thing
DPG has not yet addressed this to my knowledge
APD Layout 3G (vertical not to scale)
B. Heltsley Simulation Mtg - 07 Jun 201016
CrystalSilicone GlueEpoxy
Non-depeleted SiHi-gain active Si
Lo-gain active Si
Bulk SiCeramic
Capsule
1.65 mm
30 m
575m0.1 m
5 m45 m 400 m
Crystal
5mm
3_7_0_pre3
The Real Thing
Digitization parametersSimCalorimetry/EcalSimProducers/python/
apdSimParameters_cff.pyapdAddToBarrel = cms.bool(False), apdSeparateDigi = cms.bool(False), apdSimToPELow = cms.double(4.41e6), apdSimToPEHigh = cms.double(157.5e6), apdTimeOffset = cms.double(-10.0), apdDoPEStats = cms.bool(True), apdDigiTag = cms.string("APD"), apdShapeTstart = cms.double( 74.5 ), apdShapeTau = cms.double( 40.5 )
Shape: S(t) = A(t) ( 1 – exp[A(t)] ) where A(t) = (t – tS)/
B. Heltsley Simulation Mtg - 07 Jun 201017
The Physical APD
B. Heltsley Simulation Mtg - 07 Jun 201018
The Real Thing
Issues include:What are relevant interactions?
Thermal neutrons? K0L ? e- ?
Can GEANT simulate any of this?Thin layersSpecial physics lists?S. Banerjee investigating