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ECAL L1 Trigger efficiency w ith CRAFT Data

This study aims to determine the efficiency of the ECAL L1 Trigger using CRAFT data. The trigger information produced will be checked and the L1EM trigger efficiency will be extracted. Muon cosmics data will be used as a source of EM activity.

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ECAL L1 Trigger efficiency w ith CRAFT Data

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  1. ECAL L1 Trigger efficiency with CRAFT Data Stéphanie Baffioni, Baptiste Guegan, Pascal Paganini, Alexandre Zabi LLR-Ecole Polytechnique in collaboration with LIP Alexandre Zabi - LLR Ecole Polytechnique

  2. OUTLINE ECAL trigger efficiency with collision data:  DATASET: Gather reconstructed data that have been triggered with an unbiased trigger condition such as requiring a muon trigger. Ecal trigger objects must have been produced and saved for these events. Matching Offline info with Online: - Offline reconstructed Electron/Photon used in your analysis can be matched (in position) to trigger objects such as L1EM candidate - Trigger conditions efficiency could be determined as a function of offline pT, eta.  Adjusting threshold and selection: - Running a trigger simulation (trigger emulator) on these events allows to other trigger conditions.  No collision data yet.. but 420M events available from CRAFT, could we use them? Alexandre Zabi - LLR Ecole Polytechnique

  3. Trigger Tower 5  5 crystals barrel cystals Pb/Si preshower  = 0.087 endcap supercystals (5x5 crystals)  barrel Super Module (1700 crystals)  = 0.087 S T R I P EndCap “Dee” 3662 crystals HV  2 x12 12 bits Logic 1 x6 12bitADC 2 bits 0 MGPA x1 APD/VPT crystal 25 ns sampling VFE architecture for single channel ECAL Detector P. Paganini /LLR-IN2P3-CNRS

  4. Global Calo Trigger Global Trigger D C C … S C C S T C C L B ECAL Trigger Path Regional Calo Trigger HCAL Trigger Primitives • Per regional RCT crate: • 4 highest isolated E.M objects • 4 highest non-iso E.M objects • 4 highest central, forward,  jets • 4 isolated E.M objects • 4 non-iso E.M objects • 4 central, forward,  jets E.M objects : based on the sum of 2 Trigger Towers • ECAL Trigger Primitives for each BXs : • Trigger tower ET (8b) • Compacity bit (ECAL fine grain) Copper links = 10 m L1 accept signal !!! VME 9U ECAL Off-Detector crates : service cavern Pre-Trigger primitives @ 40 MHz, 800 Mb/s Optical fibers ≈ 70 m Front End On-Detector : experimental cavern Trigger Concentrator Card Synchro Link Board P. Paganini /LLR-IN2P3-CNRS

  5. OUTLINE During CRAFT, the ECAL Trigger has been used to generate L1EM candidate throughout the full chain including: TPG+RCT+GCT Can we use the data to check the trigger info and extract the L1EM trigger efficiency?  Checking the Trigger information produced: - Comparing the ECAL TPG produced with the Emulator - Identify problems and investigate  L1TPG efficiency: - Offline reconstructed cluster (“Electron”): can we determine the efficiency with which we produce the corresponding TPG ?  L1EM Candidate efficiency: - Match offline reconstructed object (SuperCluster) with L1EM candidate determine efficiency as a function of ET What source of EM activity could we use from Muon cosmics data? Alexandre Zabi - LLR Ecole Polytechnique

  6. DATA SET/SOFTWARE • Muons that have large bremm associated energy deposit in the ECAL could be used to perform this study •  DATASET: • - Ecal skim provided by the PFG group: consists of selecting events with • at least 1 SuperCluster (algorithm adapted to Muon reconstruction) with • E>2GeV • /Cosmics/Commissioning08_CRAFT_ALL_V4_ecalSkim_fromRECO_ecalSkim_fromRECO_v2/RECO • RUN SELECTION: • “Good” status from ECAL DPG/PFG • ECAL APD Gain 50 (nominal gain for LHC) • Selective Readout • Magnetic Field: ON and stable • ECAL trigger “ET_HARDCODED” • RCT configured with “EEG_*” and GCT configured • Run numbers: 67977, 68000, 68021, 68094, 68100, 68124, 68129, 68286, 69351, 69357, 69364, 69750, 69788, 69800, 69850, 69874, 69892, 69902 •  CMSSW_2_2_X/EcalCosmics: • - Using a lot of the code provided by the ECALCosmics analysis group to • which we added Trigger information. Alexandre Zabi - LLR Ecole Polytechnique

  7. S T C C L B Offline/ quasi online TP DAQ TP stream Comparison Emulator Individual crystal data streams Emulated TP Checking Trigger info: TPG Data vs Emulator • Per Trigger Tower/Event, 1 Trigger Primitive is sent to the DAQ • From the 10 samples ADC of 25 crystals of the TT, emulator computes • 5 possible Trigger Primitives (TP0, TP1, TP2, TP3, TP4) depending on the samples used. • Ideally, when: • The 25 crystals of the tower have been read-out • The trigger latency is the same for all towers, • The crystal data are properly timed in, • The Trigger Primitive data are properly timed in, • the TP from the data should always matchthe same TPi in the emulator Alexandre Zabi - LLR Ecole Polytechnique 7 11 March 2009 CRAFT analysis workshop

  8. Checking Trigger info: TPG Data vs Emulator Well known problems explaining why data-emulator comparison failed : • 2 ECAL trigger fibres swapped w.r.t correct position: TT17 TT18 in supermodule EB+7 z axis = index of the emulated TP matching the data relative timing (in c.u.) [-1 (black) means comparison failed, 0 (white) means no data or masked towers] • Bug in the firmware of the ECAL Trigger Concentrator Card where TPs from previous event may be mixed with the ones of current event: affects supermodule EB+8 and partially EB-7 and EB-10 Problem now solved! Alexandre Zabi - LLR Ecole Polytechnique

  9. Checking Trigger info: TPG Data vs Emulator “Without known problems” (see previous talks from Pascal), all runs ET DATA(ADC) Run: 69475 (error in data configuration) Runs: 66621 and 66627 (hot cells) No particular run Some pb in tower i=36 i=11 for runs >70127 (under unvestigation) ET Emulator (ADC) • Treatment of hot cells  remove the corresponding towers • + remove run 69475 (error in data config) • + remove run 68288 (timing problems) Runs: 66482, 66510, 66621, 66627, 67977, 68000, 68021, 68094, 68100, 68124, 68129, 68141, 68264, 68276, 68279, 68286, 68288, 68483, 68500, 68665, 68926, 68949, 68958, 69044, 69333, 69335, 69343, 69351, 69357, 69364, 69382, 69438, 69464, 69475, 69482, 69522, 69536, 69557, 69559, 69564, 69573, 69587, 69594, 69750, 69788, 69800, 69850, 69874, 69892, 69902, 69912, 69997, 70036, 70088, 70127, 70147, 70170, 70195, 70352, 70370, 70379, 70402, 70410, 70411, 70412, 70413, 70414, 70415, 70416, 70417, 70421, 70664, 70674 Alexandre Zabi - LLR Ecole Polytechnique

  10. Checking Trigger info: TPG Data vs Emulator Excellent correlation between the Data and Emulator Matching efficiency Alexandre Zabi - LLR Ecole Polytechnique

  11. Checking Trigger info: TPG Data vs Emulator For the cases where the energy matches, all runs: Fine Grain bit: used to check compatibility of shower shape with electron •  0.00014% of mismatched FG (was 0.7 % before, bugs in emul) • + better treatment when two emulated TP samples match TP data • + actions previous slide Alexandre Zabi - LLR Ecole Polytechnique

  12. Checking Trigger info: masking problematic channels • Explanation: Due to a change of parameter (TXBC0 delay) in the SLB • Delay of the ECAL trigger • Desynchronization with the other triggers • Wrong readout of Tp and crystal data Consequence: Possibilty to read out TP data from gap instead of physics orbit (laser, testpulse). High trigger rate for the whole trigger primitive range from 1 to 255. B.Guegan/LLR-IN2P3-CNRS, CERN

  13. Checking Trigger info: masking problematic channels Events with data taking problems: corresponding trigger tower masked Alexandre Zabi - LLR Ecole Polytechnique

  14. TPG efficiency ANALYSIS OVERVIEW • L1 Muon candidate present • Events not bias from EM-trigger conditions • SuperCluster must have E_crystal_max > 0.4 GeV • For reliable ECAL timing • DR(reco Muon, Supercluster) < 0.15 • Using linear extrapolation from TK outer layer to ECAL surface • Avoids SuperCluster from noise fluctuations • Is TPG produced? (matching defined later) • Corresponding TPG (ADC counts) > 0 Denominator Numerator Alexandre Zabi - LLR Ecole Polytechnique

  15. SC ECAL m TK Matched SC 0.15 TPG Efficiency: Denominator The SC are matched to reconstructed global muons to insure they are coming from Muon brem signal in ECAL DR(reco Muon, Supercluster) Muons @ ECAL surface Alexandre Zabi - LLR Ecole Polytechnique

  16. TPG Efficiency: Timing requirements Crystal time extracted from the fit of 10 time samples to the expected shape. Clear correlation between the xtal time and the Bx assignment.  Dealing here with not on-time muons (not synchronized with any bunch crossing ): applying timing requirements for reliable trigger info. Alexandre Zabi - LLR Ecole Polytechnique

  17. TPG efficiency: Denominator • Starting point: define what we consider as offline reconstructed “electron” • “Electron” = the TOWER containing the most energetic Xtal of the SC seed cluster • Tower energy: summing energy in each crystal Tower ET (GeV) no intercalibration TP ET (GeV) Good energy correspondence between offline (“Electron”) and online (TPG) objects if no intercalibration constants used. Alexandre Zabi - LLR Ecole Polytechnique

  18. TPG efficiency: Numerator Matching TPG with offline reconstructed object (SuperCluster): Considering the Tower (25 crystals) which contains the crystal with the maximum energy of the SuperCluster. There is matching if the corresponding TPG has been produced (>0) Note: - No TPG produced bellow 750 MeV - 97% efficiency reached at 1.5 GeV Under investigation: - Late turn-on curve (Zero-Suppression responsible?) - Not 100% efficient Alexandre Zabi - LLR Ecole Polytechnique

  19. L1EM CANDIDATE EFFICIENCY ANALYSIS OVERVIEW performed by LIP group • L1 Muon candidate present • Avoid bias from EM-triggered events • At least one global reco Muon • Supercluster must have E_crystal_max > 0.4 GeV • For reliable ECAL timing • DR(reco Muon, Supercluster) < 0.15 • Using linear extrapolation from TK outer layer to ECAL surface • Ensures that the Supercluster is not noise • Finally, system is considered efficient if • EM L1cand found and DR(EM L1cand, Supercluster) < 0.5 Denominator Numerator (F. De Guio et al) Alexandre Zabi - LLR Ecole Polytechnique

  20. Two superclusters One L1 Candidate Matched EM L1 cand L1EM CANDIDATE EFFICIENCY: Numerator DR (EM L1cand, SC) EM candidate produced by the GCT is efficient if it is close to a reconstructed Supercluster. Alexandre Zabi - LLR Ecole Polytechnique

  21. L1EM CANDIDATE EFFICIENCY: Timing requirements Alexandre Zabi - LLR Ecole Polytechnique

  22. SUMMARY/OUTLOOK • The ECAL L1 trigger has been used in CRAFT • The data match the emulated data at the TPG level but we still have to • understand remaining 0.1% difference. • L1 TPG efficiency • The first efficiency curves have been extracted from Muon data. • Turn-on curves visible above the 1GeV trigger threshold and plateau • at 97%. 3% missing under investigation: L1EM emulator on the full • TPG+RCT+GCT chain • Good start to develop the tools to assess Trigger efficiencies with collision data Alexandre Zabi - LLR Ecole Polytechnique

  23. CMS Trigger 1 Bunch crossing / 25 ns 40 000 000 Hz, ≈ 1000 TB/s ≈ 109 interactions/s Level 1 Trigger 100 000 Hz, 150 GB/s Dedicated Hardware (ECAL + HCAL + Muon) ECAL Trigger Primitives: 1ststep of L1 ECAL trigger ECAL electronics <---- 1.5 MB / evt) ----> High Level Trigger 150 Hz, 225 MB/s Computer farm Alexandre Zabi - LLR Ecole Polytechnique

  24. The ECAL Trigger Primitives: first stage of ECAL Trigger Linear filter: Weighted sum with 5 weights Only positive values are kept (otherwise 0) Raw samples Linear pulse Linearizer Strip pulse Filtered pulse Strip ET Linearizer 5 crystals from VFE (1 strip) Peak Finder Linearizer Filter Linearizer Multiplies ADC by gain ratio (MGPA) after pedestal subtraction, calibration coefficient and sin() to compute ET Sets ET saturation scale Linearizer P. Paganini /LLR-IN2P3-CNRS

  25. The ECAL Trigger Primitives: first stage of ECAL Trigger Look Up Table (1024 values) Triggering on cosmic: ‘identity LUT’ (with min-threshold) to keep the LSB as low as possible Beam :non-linear LUT based on ECAL resolution (ie LSB should follow (ET)/ET) Strip ET Tower ET 10b Tower ET 8b TP (9b) = ET 8b + FG 1b Per Trigger Tower For each BX Compression Tower FG 1b Fine Grain Filter Used to characterize transversal profile of EM shower Required for the EM streams  ) > ratio x ET( ) Max ET( P. Paganini /LLR-IN2P3-CNRS

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