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