ecal simulation status & plans brian heltsley simulation mtg 26 apr 2010
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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?
B. Heltsley Simulation Mtg - 26 Apr 20102
The Real Thing
DPG has not yet addressed this to my knowledge
APD Layout 3G (vertical not to scale)
B. Heltsley Simulation Mtg - 26 Apr 20103
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 ?).
B. Heltsley Simulation Mtg - 26 Apr 20104
Commissioning-PromptReco-v7 vs REDIGI_MinBias7TeV
B. Heltsley Simulation Mtg - 26 Apr 20105
EB EE+ EE-
OccupancyModelingImproves
Commissioning-PromptReco-v7 vs REDIGI_MinBias7TeV
B. Heltsley Simulation Mtg - 26 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
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 ?)
B. Heltsley Simulation Mtg - 26 Apr 20107
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)
B. Heltsley Simulation Mtg - 26 Apr 20108
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
B. Heltsley Simulation Mtg - 26 Apr 201010
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
B. Heltsley Simulation Mtg - 26 Apr 201012
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!
B. Heltsley Simulation Mtg - 26 Apr 201013
B. Heltsley Simulation Mtg - 26 Apr 201014
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
B. Heltsley Simulation Mtg - 26 Apr 201015
Measured Correlations
B. Heltsley Simulation Mtg - 26 Apr 201016
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 Simulation Mtg - 26 Apr 201017
The Physical APD
B. Heltsley Simulation Mtg - 26 Apr 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
Tentative 2nd Generation APD
B. Heltsley Simulation Mtg - 26 Apr 201019
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…
B. Heltsley Simulation Mtg - 26 Apr 201020
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%)
B. Heltsley Simulation Mtg - 26 Apr 201021
from CMSCommonData/data/materials.xml
Other views
B. Heltsley Simulation Mtg - 26 Apr 201022
Crystal
Side View, magnified thicknesses
Crystal
Front View, Correct thicknesses
B. Heltsley Simulation Mtg - 26 Apr 201023
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)
B. Heltsley Simulation Mtg - 26 Apr 201024
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
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