ecal simulation status & plans brian heltsley simulation mtg 26 apr 2010

B. Heltsley Simulation Mtg - 26 Apr 20101

Ecal Simulation Status & Plans

Brian Heltsley

Simulation Mtg 26 Apr 2010

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 Digitization– Tag 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?


The Real Thing

DPG has not yet addressed this to my knowledge

APD Layout 3G (vertical not to scale)


CrystalSilicone GlueEpoxy

Non-depeleted SiHi-gain active Si

Lo-gain active Si

Bulk SiCeramic

Capsule

1.65 mm

30 m

375?m0.1 m

5 m45 m 400 m

Crystal

5mm

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!!)

After we were late in the above validation, & had several glimmers of hope for 360_pre?, it has appeared in CMSSW_3_7_0_pre1 & been validated (& perhaps back-propagated to 3_6_1 ?).


Commissioning-PromptReco-v7 vs REDIGI_MinBias7TeV


EB EE+ EE-

OccupancyModelingImproves

Commissioning-PromptReco-v7 vs REDIGI_MinBias7TeV


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

Got entangled with EB/EE noise model changes, & associated ES Reco code/DB changes, & is installed in CMSSW_3_7_0_pre1 (& perhaps back-propagated to 3_6_1 ?)


Data

New MC

Old MC

Sim changes in progressTest 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)


Simulation HousekeepingThese already done for 3_7_0_pre1– Just 10 numbers per correlation matrix instead of 100– Reform EB & EE analog hit response handling

• Current practice makes a new CaloHitResponse object for all DetId’s (one ‘new’ & one ‘delete’ per DetId per event !)

• New practice: create object once per job, modify

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

– Looking at these & further changes for, possibly, 38XB. Heltsley Simulation Mtg - 26 Apr 2010

9

Backup slides


Which Calos can be aligned?

Ecal– EB: barrel– EE: endcap– ES: preshower

Hcal– HB: barrel– HO: outer– HE: endcap– HF: forward

Forward– ZDC: zero-degree calorimeter @ 140m– Castor

CaloTower : a reco object which might need alignmentB. Heltsley Simulation Mtg - 26 Apr 2010

11


Application of Calo Alignments

If applyAlignment parameter is set, a given calo has alignments applied– This part is part of generic/templated code– Alignment from GlobalAlignmentRcd for that calo

applied for all volumes– Calo cells are grouped together into the physical

construction objects for alignments• EB: by supermodule level (36 alignments)• EE: by Dee (4 alignments)• ES: by Dee and layer• Others in sensible groupings

Short term alignment goals

Insert global tracker alignment into various calo alignment slots in DB

Load dummy ‘zero’ alignments payloads into DB

Turn on alignment flags for calos

Have this as a standard asap so that when alignments do become known, it is only a matter of inserting new payloads

HAS NOT HAPPENED YET!



Measuring Alignments

Three parallel efforts in progress– Preshower: Ming Kuo has begun examining offsets

between projected tracks & hit strips in ES– Electrons (Ecal only) [no new work in >1 year]

• Select an “appropriate” sample of electrons• Compare extrapolated Track to matched Supercluster

position• For each e have an expected & measured position• Then, probably proceed in a manner similar to other

alignment algorithms

– Cosmic rays (Ecal & Hcal)• Cornell student Gala Nicolas-Kaufman beginning to help• Not yet demonstrated that it is useful• Start with zero-field data from CRAFT2009

EB, EE noise in simulationSee last month’s talk for details of issues

EB, EE noise simulation in <=CMSSW_3_6_0:– Needed time-correlations accounted for among ten

samples for each crystal– Needed separate correlations for EB, EE– Had wrong single sample noise value– Had different SR/ZS thresholds than used online

Improvements were identified & tested– W/correlations, measured single sample noise can be

used in simulation to improve agreement w/data– Ditto for ZS threshold


Measured Correlations


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


The Physical APD


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

Tentative 2nd Generation APD


Picture from iguana 3_5_0_pre5

Thicknesses magnified for visualization purposes

Plastic Capsule4mm

“Ceramic” case1.6mm

Bulk Silicon400µ

Epoxy200µ

Non-depeleted Si0.1µ

Sensitive 5µ Si

Less sensitive 45µ Si

CrystalAPD Geometry Implementation by B. Heltsley

S. Banerjee: making SimHitsJ. Branson: running studies

But is a simple APD good enough?

Perhaps

Perhaps not (Jim Branson et al.)– If Ecal spikes are related to APDs, perhaps

more detail would help us understand what is happening

– Details of APD response and local materials can potentially make a difference

• e.g. Protective epoxy coating has ‘lots of oxygen’ which has larger neutron cross section.

• Won’t know unless we try it, so…


APD Names & materialsNumbered from 01-17 – # different barrel crystal shapes– Even though identical, must have different names because they

reside in differently-named mother volumes

EAPD_nn: sensitive volume (higher gain): Si

EATJ_nn: sensitive volume (lower gain): Si– (“After The Junction”)

EGLU_nn: Epoxy: C (54%), H (13%), O(33%)

EBSi_nn: Bulk Si

ECER_nn: Ceramic (?) package: Si(30%), O(48%), K(6%)– Using Borosilicate_Glass until actual composition is known

EAND_nn: Non-Depleted layer: Si

ECAP_nn: PEEK Capsule: C (54%), H (13%), O(33%)


from CMSCommonData/data/materials.xml

Other views


Crystal

Side View, magnified thicknesses

Crystal

Front View, Correct thicknesses


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, but Sunanda Banerjee has a private tarball of changes to make these volumes active and generate SimHits.

APD Layout (not to scale)


CrystalSilicone GlueEpoxy

Non-depeleted SiHi-gain active Si

Lo-gain active Si

Bulk SiCeramic

Capsule

1.65 mm

30 m

600m0.1 m

5 m45 m 400 m

ecal simulation status & plans brian heltsley simulation mtg 26 apr 2010

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