Ecal Simulation Status Ecal Shape Status & validation SLHC Ecal simulation needs

1. Ecal Simulation Status • Ecal Shape Status & validation • SLHC Ecal simulation needs • Ecal noise improvement plans • 1st/2nd Generation APD Simulation Brian Heltsley Ecal DPG 11 Feb 2010 B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

2. EE Shape Validation • Historical summary (previously reported) • Structural changes to Ecal code relating to having separate EB & EE shapes was ready last fall. First stage went into 3_4_0 which had separate EE shape classes but kept the EB shape for the EE object, so no real change in behavior. (B. Heltsley) • C. Neu extracted EE pulse shape from EE TB data & this was checked into CMSSW into the EE class but not published • K. Theofilatos extracted the necessary EE weights from the above that are used in the reconstruction • Weights needed to put into the DB (help from J. Fay, F. Cavallari, …) • Coordination along the way from F. Ferri, M. Hildreth, T. Tabarelli, … • BUT • Validation was plagued by puzzles which it was thought better to solve than have any doubt • Finally B. Gobbo stepped up to the plate to provide the definitive validation assurances. B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

3. EE Shape validation Grazie, Benigno! New shape (black) Is different! RecHit/SimHit is the same! All changes to go into CMSSW_3_6_0_pre1. Thanks to the Very very many people who contributed to this completion. B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

4. SLHC Ecal Simulation • What is required of Ecal Simulation to plan for the SLHC? • Chris Neu (U.Va.) organized an initial meeting of some interested parties • C. Neu, C. Jessop, B. Cox, S. Banerjee, R. Ruchti, B. Heltsley • Just getting started … • Time slot is tentatively Fridays 14:00 Eastern time, 20:00 CERN time, as convenient for these participants & open • Chris should give an update in a few weeks B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

5. Ecal Noise Plans • Ecal noise simulation to be improved • T. Tabarelli de Fatis has outlined a plan for us in the simulation group to follow • Resurrect the (time-dimension) correlation matrix code for the barrel • Make structural changes to have a separate correlation matrix for the endcap • Adjust other parameters as necessary so as to match reality as closely as possible; will require iterative procedure • Simulate noisy channels in inner EE • C. Neu & myself to implement, preferably for CMSSW_3_6_0_pre1 or pre2 • Details to follow B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

6. Other matters • L1 Emulator Update • How to make a L1 ‘spike’ veto? • J. Jackson (Bristol) has implemeted some necessary tools in CMSSW_3_5_0_pre? • Studying different algorithms & thresholds • Work in progress… • ES gain: preshower gain needs to be adjusted in the cfg (C.M. Kuo) B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

7. 5x5 mm2 APDs initially present in simulation as shown APD thickness magnified greatly for visualization purposes – actual thickness in simulation is 5m. Material is Si. Inactive by default, but Sunanda Banerjee has a private tarball of changes to make these volumes active and generate SimHits. See Jim Branson’s talk following this one. B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

8. 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 Ecal DPG Sim Status - 11 Feb 2010

9. The Physical APD Top 100 has ~20% Boron B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

10. Notes on real APD • Two active layers • Different thicknesses & gains • Epoxy coating on front • Bulk inactive Si on back & sides • Top 100m formed by Boron implantation & diffusion at ~20% concentration • 2 stable isotopes of Boron (Z=5) • 115B5 has 80% abundance, JP=3/2 • 105B5 has 20% abundance, JP=3+ • 10B + n  7Li (0.84 MeV) + (1.47 MeV)  has =3840 barns for thermal neutrons. •  drops with increasing neutron energy as 1/velocity • Can GEANT simulate any of this? • Sunanda Banerjee investigating Technical information courtesy of Yuri Musienko & Jim Branson The Real Thing B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

11. Tentative 2nd Generation APD “Ceramic” case 1.6mm Bulk Silicon 400µ Plastic Capsule 4mm Less sensitive 45µ Si Sensitive 5µ Si  Non-depeleted Si 0.1µ APD Geometry Implementation by B. Heltsley Epoxy 200µ Crystal B. Heltsley Ecal DPG Sim Status - 11 Feb 2010 Picture from iguana 3_5_0_pre5 Thicknesses magnified for visualization purposes

12. Other views Side View, magnified thicknesses  Crystal Front View, Correct thicknesses  Crystal B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

13. APD Names & materials from CMSCommonData/data/materials.xml • Numbered 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 (add Boron?) • 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 (add Boron?) • ECAP_nn: PEEK Capsule: C (54%), H (13%), O(33%) B. Heltsley Ecal DPG Sim Status - 11 Feb 2010

14. Modified files • Geometry/EcalCommonData/ • data/ebalgo.xml • interface/DDEcalBarrelAlgo.h • src/DDEcalBarrelAlgo.cc • src/EcalBarrelNumberingScheme.cc • These 4 files are in • /afs/cern.ch/user/h/heltsley/public/apdbkh • Builds in CMSSW_3_5_0_pre5 • Slight mods will be needed for pre6 due to DDD changes by Michael Case • Feedback appreciated • Sunanda has adapted his code to return depth=1 & depth=2 for the 2 APD layers (crystal has depth=0) • See next talk for status of testing B. Heltsley Ecal DPG Sim Status - 11 Feb 2010