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Ecal Simulation Status Report Brian Heltsley Full Simulation Mtg CMS Week 14 June 2010 Focus for last 3 months Improved noise models APD simulation studies Housekeeping. Measured Correlations. Numbers from Sasha Ledovskoy EB & EE have different correlations - PowerPoint PPT Presentation
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B. Heltsley Simulation Mtg - 15 Jun 20101
Ecal Simulation
Status ReportBrian Heltsley
Full Simulation Mtg
CMS Week
14 June 2010
Focus for last 3 months• Improved noise models• APD simulation studies
• Housekeeping
Measured Correlations
B. Heltsley Ecal Status@Sim Mtg - 12 Apr 20102
Numbers from Sasha LedovskoyEB & EE have different correlations
Noise frequency is higher in EE than EBBoth have high correlations in neighboring samples
RecHit Energy Spectrum MC/data agreement improves using measured
(fixed) ’s, online ZS/SR:(EB)=1.089, ZS/SR(EB)=78.75 MeV;(EE)=2.018, ZS/SR(EE)=225 MeV
B. Heltsley Ecal Status@Sim Mtg - 12 Apr 20103
Recent Noise ProgressStructural code changes allowing separate EB, EE correlation matrices completed in CMSSW_3_6_0_pre3, but values still set to identity
Tag set prepared using – measured correlations– Fixed, measured ’s (i.e. same for all channels) – online ZS/SR thresholds
Above tag set fully validated with REDIGI of MIN_BIAS MC (next slides) (lots of work by many people!!)
Was taken for CMSSW_3_7_0_pre1 & back-ported to 3_6_1
B. Heltsley Ecal Status@Sim Mtg - 12 Apr 20104
Commissioning-PromptReco-v7 vs REDIGI_MinBias7TeV
B. Heltsley Ecal Status@Sim Mtg - 12 Apr 20105
EB EE+ EE-
OccupancyModelingImproves
Commissioning-PromptReco-v7 vs REDIGI_MinBias7TeV
B. Heltsley Ecal Status@Sim Mtg - 12 Apr 20106
EB EE+ EE-
354p1 354p1
Timing ResolutionModelingImproves
Data
ES DevelopmentsChanges & validations from CM Kuo
Up until now, several ES MC values have been set in the cfg file only– Pedestals
– Gain (hi or lo)
– MIPtoADC
– MIPtokeV
– ZS threshold
ZS algorithm not same as online
Tag set & DB payloads created which fix the above
Installed for CMSSW_3_7_0_pre1 & back-ported to 3_6_1
B. Heltsley Ecal Status@Sim Mtg - 12 Apr 20107
Data
New MC
Old MC
APD SimulationJanuary– Could EB spikes be from energy deposition in APDs (2 behind
each crystal)? Yes
February & March– Are geometry & material details important? Yes
April– Do existing GEANT cutoffs hurt APD simulation? Yes
May– Can we tune APD digitization parameters using data with
a large MIN_BIAS sample? Yes
June– Can APD simulation be an option in CMSSW? Yes
B. Heltsley Simulation Mtg - 15 Jun 20108
Many Contributors!ASCTF (T. Virdee) & EcalDPG (T. Tabarelli, A. Bornheim)– Guidance, priorities
S. Banerjee– GEANT implementation & performance
I. Musienko, Q. Ingram– Specifications & materials
B. Heltsley– Geometry implementation & Digitization
A. Holzner– Analysis & MIN_BIAS production
J. Branson, M. Malberti, L. Di Matteo, D. Petyt– Analysis, comparisons with data
Probably others!! (apologies for omissions)B. Heltsley Simulation Mtg - 15 Jun 2010
9
B. Heltsley Ecal Status@Sim Mtg - 16 Mar 201010
5x5 mm2 APDs initially present in simulation as shown
APD thickness magnified greatly for visualization purposes – actual (potentially active) thickness in original simulation is 5m. Material is Si.
Inactive by default
Origin of APD deposition?
B. Heltsley Simulation Mtg - 15 Jun 201011
-
+
KLn
n
-
+n
nKL
From J. Branson
B. Heltsley Simulation Mtg - 15 Jun 201012
APD Layout 3G (vertical not to scale)
B. Heltsley Simulation Mtg - 15 Jun 201013
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
Why local materials are important to simulation
B. Heltsley Simulation Mtg - 15 Jun 201014
Z
APD
Epoxy
100 m
From J. Branson
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 - 15 Jun 201015
Study of APD-MC Re-Digi
B. Heltsley Simulation Mtg - 15 Jun 201016
From
M. M
alber
ti
Number
B. Heltsley Simulation Mtg - 15 Jun 201017Fro
m M
. Mal
berti
Energy
B. Heltsley Simulation Mtg - 15 Jun 201018
APD energies probably a bit too high
From
M. M
alber
ti
E4/E1
B. Heltsley Simulation Mtg - 15 Jun 201019
Too many spikes!
From
M. M
alber
ti
GEANT Performance
B. Heltsley Simulation Mtg - 15 Jun 201020
From
S. B
aner
jee
Timing
B. Heltsley Simulation Mtg - 15 Jun 201021
GEANT Performance
B. Heltsley Simulation Mtg - 15 Jun 201022
From
S. B
aner
jee
+17%
+5%
+9%
APD Simulation Conclusions
Many qualitative features of the data which were previously completely missing from simulation can now be modeled (surprisingly well)
As of CMSSW_3_8_0_pre3– APD’s will be ACTIVE at GEANT stage of simulation
• Permits later reDigi+reReco when those are understood better
• Modest CPU penalty
– Digitization of APD SimHits will be performed, but saved only in a dedicated, tagged collection (which is small)
• Experts can study APD even in default generation
• We have moved APD pulse backward by 5 ns additional
• We have reduced both layer gains by 20%
B. Heltsley Simulation Mtg - 15 Jun 201023
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? – Studies in progress by T. Tabarelli & F. de Guio
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 - 15 Jun 201024
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 - 15 Jun 201025