1. B. Heltsley Simulation Mtg - 07 Jun 2010 1 Ecal Simulation Report Brian Heltsley Simulation Mtg 07 June 2010

2. 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 B. Heltsley Simulation Mtg - 07 Jun 2010 2

3. Ecal Alignment News ES Alignment studied B. Heltsley Simulation Mtg - 07 Jun 2010 3

4. More on alignment Egamma 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 2010 4

5. Alignment validation Tried 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 2010 5

6. Study of APD-MC Re-Digi B. Heltsley Simulation Mtg - 07 Jun 2010 6

7. Number B. Heltsley Simulation Mtg - 07 Jun 2010 7

8. Energy B. Heltsley Simulation Mtg - 07 Jun 2010 8 APD energies probably a bit too high

9. E4/E1 B. Heltsley Simulation Mtg - 07 Jun 2010 9 Too many spikes!

10. Timing B. Heltsley Simulation Mtg - 07 Jun 2010 10

11. 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 2010 11

12. 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 2010 12

13. 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 ) 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 2010 13

14. Backup slides B. Heltsley Simulation Mtg - 07 Jun 2010 14

15. APD Simulation 3 rd 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 - 07 Jun 2010 15 The Real Thing DPG has not yet addressed this to my knowledge

16. APD Layout 3G (vertical not to scale) B. Heltsley Simulation Mtg - 07 Jun 2010 16 Crystal Silicone Glue Epoxy Non-depeleted Si Hi-gain active Si Lo-gain active Si Bulk Si Ceramic Capsule 1.65 mm 30  m 575  m 0.1  m 5  m 45  m 400  m Crystal 5mm 3_7_0_pre3 The Real Thing

17. Digitization parameters SimCalorimetry/EcalSimProducers/python/ apdSimParameters_cff.py apdAddToBarrel = 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 2010 17

18. The Physical APD B. Heltsley Simulation Mtg - 07 Jun 2010 18 The Real Thing Issues include:  What are relevant interactions?  Thermal neutrons? K 0 L ? e - ?  Can GEANT simulate any of this?  Thin layers  Special physics lists?  S. Banerjee investigating