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HLT Calorimeter improvements

HLT Calorimeter improvements. Ignacio Aracena SLAC ATLAS Forum November 14 2007. Outline. Introduction The ATLAS Trigger/DAQ system The ATLAS Calorimeter The FEB data unpacking The Jet Trigger Slice The Missing ET Trigger Slice Use case of L2 FEB jets Summary. Trigger. DAQ.

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HLT Calorimeter improvements

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  1. HLT Calorimeter improvements Ignacio Aracena SLAC ATLAS Forum November 14 2007

  2. Outline • Introduction • The ATLAS Trigger/DAQ system • The ATLAS Calorimeter • The FEB data unpacking • The Jet Trigger Slice • The Missing ET Trigger Slice • Use case of L2 FEB jets • Summary

  3. Trigger DAQ Calo MuTrCh Other detectors Level 1 40 MHz 2.5 ms Det. R/O L1 accept (100 kHz) ROIB L2SV DFM ROD ROD ROD Region of Interest (RoI) Dataflow High Level Trigger ~10 ms ROB ROB ROB L2 ReadOutSystem RoI requests RoI data (~2%) L2N L2PU EBN L2 accept (~3.5 kHz) Event Builder SFI EFN EFP ~ sec EF SFO EF accept (~0.2 kHz) The ATLAS Trigger/DAQ system

  4. Trigger DAQ Calo MuTrCh Other detectors Level 1 40 MHz 2.5 ms Det. R/O L1 accept (100 kHz) ROIB L2SV DFM ROD ROD ROD Region of Interest (RoI) Dataflow High Level Trigger ROB ROB ROB ~10 ms L2 ReadOutSystem RoI requests RoI data (~2%) L2N L2PU EBN L2 accept (~3.5 kHz) Event Builder SFI EFN EFP ~ sec EF SFO EF accept (~0.2 kHz) The ATLAS Trigger/DAQ system Timing constraints implies fast data access from L2 to ROS and fast algorithms at L2 and EF

  5. The ATLAS Calorimeters • EM calorimeter • LAr/Pb calorimeter • 3 long. samplings (+presampler) • DhxDj ≈ 0.025x0.025, 170K cells • Hadronic Calorimeter • Scintillator Tiles/Iron plates in barrel (|h|<1.7) • DhxDj ≈ 0.1x0.1, 10K cells • LAr/Cu in end-caps (HEC) (1.5 < |h| < 3.2) • DhxDj = 0.1x0.1 (1.5 < |h| < 2.5) • DhxDj = 0.2x0.2 (2.5 < |h| < 3.2) • Forward Calorimeter • 3.1 < |h| < 4.9 • DhxDj = 0.2x0.2 LAr barrel + HEC has ~180K cells

  6. The FEB data unpacking • Problem • Reading information from LAr Calorimeter cells is slow for the trigger • Large amount of data to be transfered over the TDAQ network • Long processing time of trigger algorithms • Idea • Use information from the LAr Front-End Boards (FEB) • Each FEB receives signals from 128 calorimeter cells • Use sums over calorimeter cells

  7. Detectors Level 1 Det. R/O DFM ROIB L2SV ROD ROD ROD Dataflow High Level Trigger L2 ROS ROB ROB ROB L2N L2P EB EBN SFI EFN EFP EF SFO The FEB data unpacking FEB sums are computed in the RODs No additional computing time at L2, but less data than using all cells! Use cases for FEB unpacking: (i) Level-2 jets (ii) Event Filter Missing ET

  8. The Jet trigger slice

  9. L1 JETROI T2CaloJet time L2 TrigL2JetHypo TrigCaloCellMaker TrigCaloTowerMaker EF TrigJetRec TrigJetHypo The Jet trigger slice • Level 1 • Sliding 0.8x0.8 window (4x4 L1 jet elements) • Level 2 • Feature Extraction (FEX) algorithm T2CaloJet • Hypo Algo TrigL2JetHypo: Cut on jet ET • Event Filter • FEX algorithms: • TrigCaloCellMaker: data unpacking • TrigCaloTowerMaker: Calorimeter towers • TrigJetRec: Jet reconstruction • Hypo algorithm • TrigJetHypo: Cut on jet ET

  10. The Level-2 jet trigger Seeded by Level-1 jet RoI • Sum of trigger towers (4x4) with ET and h, j position • Trigger Towers = sums of calorimeter cells in DhxDj=0.2x0.2 Level-2 jet algorithm executes three tools: • Data preparation • Choice between cell (cell jets) or FEB granularity (FEB jets) • Read out region DhxDj=1.0x1.0 with center at L1 jet RoI position • Cone algorithm • Assume cone-shaped jet with RCone=0.4 • Calibration • Apply energy correction term for LAr, Tile, HEC

  11. The L2 FEB jets – old results Previous study showed the L2 FEB jets work in |h| < 1.5 (SLAC-ATLAS forum, May 2 2007) Problem: Strange shape in L2 Jet E vs MC jet E, side branches splitting off from main branch! QCD dijets (J5) Update: Fix mapping problems in the HEC fix bug in conversion from Ex, Ey, Ez to L2 jet h and j New FEB sum calculation applies noise cut: new noise cut!

  12. L2 FEB jet ene vs MC jet energy - |h|<3.2 70 < pT < 140 GeV 140 < pT < 280 GeV J4 J3 280 < pT < 560 GeV 560 < pT < 1120 GeV J5 J6

  13. L2 FEB jet energy scale • L2 FEB jets energy scale with respect to MC truth jet • athena 13.0.30 + fix for FEB (2*snoise cut) • DR(L2 jet – MC truth jet) < 0.07 Energy scale within 5% in most of the region Note: No special FEB calibration used! Applied calibration weights were derived from cell-based Level-2 jets! Compare with L2 cell jet energy scale Energy scale >95%, except for jets with E<200GeV and 1.5 < |h| < 2.5

  14. The L2 FEB jet energy resolution Athena 13.0.30 + FEB fix QCD dijets L2 FEB jets energy resolution Compare with cell jets energy resolution

  15. L2 FEB jet position resolution Athena 13.0.30 + FEB fix QCD dijets, 140 < PT < 280 GeV (J4) • Dj (L2 – MC) / (MC truth jet phi) • RMS ~ 0.05 for J4 sample • Dh (L2 – MC) / (MC truth jet eta) • RMS ~ 0.07 for J4 sample

  16. L2 FEB jet position resolution Athena 13.0.30 + FEB fix QCD dijets, 280 < PT < 560 GeV (J5) • Dj (L2 – MC) / (MC truth jet phi) • RMS ~ 0.04 for J5 sample • Dh (L2 – MC) / (MC truth jet eta) • RMS ~ 0.08 for J5 sample

  17. No. events with L2 jet PT > L2 signature eff. = All events with matched offline jet Level-2 jet turn-on curves Athena 13.0.30 + FEB fix QCD dijets cell jets Level-2 jet improves turn-on curve wrt Level-1 Cell and FEB jet have comparable turn-on curves

  18. No. events with L2 jet PT > L2 signature eff. = All events with matched offline jet Level-2 jet turn-on curves Athena 13.0.30 + FEB fix QCD dijets cell jets Level-2 jet improves turn-on curve wrt Level-1 Cell and FEB jet have comparable turn-on curves

  19. Pure Alg processing time + data collection time DFM ROIB L2SV ROD ROD ROD FEB unpacking (mean 52ms) ROB ROB ROB Cell unpacking (mean 69ms) L2N input : Bytestream with J4 dijets 140 < PT < 280 GeV L2P EBN SFI EFN EFP SFO L2 FEB jets in online system (i) Measure timing in a realistic environment: Use “Preseries” machines installed in Point 1 Detectors Det. R/O Level 1 Dataflow High Level Trigger L2 ROS EB EF FEB unpacking ~17ms (~25%) faster on Preseries. Preparations ongoing for tests in next week’s technical run with the ATLAS TDAQ

  20. L2 FEB jets in online system (ii) From test in online environment in the preseries Two separate runs: (i) FEB based unpacking (ii) cell based unpacking Histograms not normalized to same number of processed events FEB unpacking Cell unpacking input : Bytestream with J4 dijets Good agreement between both methods (FEB vs cells). New 2*snoise cut in LAr bytestream encoding works well. First tests with real TDAQ system in next week’s technical run.

  21. Recent studies in the jet slice Summary of recent studies presented during Nov. T&P weeks: • FEB studies (I.A.) • Update Event Filter jet calibration (Cibran Santamarina et al, McGill U., Montreal) • Pile-up studies in 1033 scenario (Wendy Taylor et al, York U. Toronto) • Energy scale studies (Patricia Conde et al, LIP Lisbon) • Impact of extra detector material • In Z→mm + jet events

  22. Extra material in trig1_calib1 clearly affects the energy scale. In crack region energy underestimated by > 5%. ~ Level-2 jet energy scale (i) Use samples with misalignment and miscalibration: trig1_calib1 resolution fit trig0_calib0: resolution fit: Worse resolution for large h regions (Patricia Conde et al.)

  23. Level-2 jet energy scale (ii) Study the L2 jet energy scale with Z → mm events EM energy fraction is event dependent (prod. mechanism) (Patricia Conde et al.) Z+partons →mm+jets, samples 8143/8144 12.0.6.4 Larger EM energy fraction for Z→mm + jets with E > 100GeV Energy scale is overestimated New method :Introduce dependency on EM energy fraction in the calibration (Chicago calibration method)

  24. The Missing ET trigger slice

  25. L1 MET T2MissingET L2 TrigL2MissingETHypo EFMissingET EF TrigEFMissingETHypo The Missing ET slice • Level 1 • MET and sumET computation based on Jet elements (Trigger towers) • Level 2 • One FEX algorithm T2MissingET • “dummy” algorithm: forward L1 MET to EF • Hypo Algo TrigL2MissingETHypo: • Cut on MET or sumET • Event Filter • One FEX algorithm EFMissingET • sum over all cells or all FEBs • Hypo algorithm TrigEFMissingETHypo • Cut on MET or sumET time

  26. FEB cell cells with e > 2*snoise EF Missing ET – METX and METY Same fixes as for L2 FEB jets improve also FEB MissingET in the Event Filter Default EF MET with cell granularity has no noise cut QCD dijet events, 140 < PT < 280 GeV, athena 13.0.30 + FEB fix J4 J4

  27. FEB cell cells with e > 2*snoise EF Missing ET – sumET and MET Same fixes as for L2 FEB jets improve also FEB MissingET in the Event Filter Default EF MET with cell granularity has no noise cut QCD dijet events, 140 < PT < 280 GeV, athena 13.0.30 + FEB fix J4 J4

  28. DFM ROIB L2SV High Level Trigger L2 ROS ROB ROB ROB L2N L2P EB EBN SFI EFN EFP EF SFO EF MissinET - timing • Timing measurement in offline framework (athena.py) • FEB method is ~4 times faster than cell method • Online tests scheduled for technical run FEB cell 2327MHz CPU (pcphuat27) Pure algorithm processing time

  29. L1 METx L2 mHTx Use case of L2 FEB jets – L2 mHT Missing ET computation at Level-2 is considered too time consuming Currently no real Level-2 Missing ET algorithm: bypass L1 MET, possible to correct for muon contribution Use fast (FEB) Level-2 jets for missing ET: mHT QCD dijets, 140<PT<280GeV Longer tails with L2 mHT than with L1 MET. Work in progress.

  30. Summary FEB data unpacking: • Bugfixes and new FEB Ex, Ey, Ez computation • Cut at 2*snoise gives best performance • FEB method and cell method have similar performance • Timing measurements • Level-2 jets 25% faster with FEB (online, on the preseries) • EF Missing ET ~4 times faster with FEB (offline environment) • Open issue: Database access of LAr constants during data-taking Level-2 mHT: • First look into Level-2 mHT based on Level-2 FEB jets • No improvement in resolution wrt L1 MET • Use L2 mHT to reject fake Missing ET

  31. BACKUP SLIDES

  32. L2 FEB jet position resolution Athena 13.0.30 + FEB fix QCD dijets, 560 < PT < 1120 GeV (J6) • Dj (L2 – MC) / (MC truth jet phi) • RMS ~ 0.04 for J6 sample • Dh (L2 – MC) / (MC truth jet eta) • RMS ~ 0.08 for J6 sample

  33. L2 FEB jet position resolution Athena 13.0.30 + FEB fix QCD dijets, 1120 < PT < 2240 GeV (J7) • Dj (L2 – MC) / (MC truth jet phi) • RMS ~ 0.04 for J7 sample • Dh (L2 – MC) / (MC truth jet eta) • RMS ~ 0.09 for J7 sample

  34. No. events with L2 jet PT > L2 signature eff. = All events with matched truth jet Level-2 jet turn-on curves Athena 13.0.30 + FEB fix QCD dijets cell jets Level-2 jet improves turn-on curve wrt Level-1 Cell and FEB jet have comparable turn-on curves

  35. No. events with L2 jet PT > L2 signature eff. = All events with matched truth jet Level-2 jet turn-on curves Athena 13.0.30 + FEB fix QCD dijets cell jets Level-2 jet improves turn-on curve wrt Level-1 Cell and FEB jet have comparable turn-on curves

  36. L2 FEB jet energy scale • L2 FEB jets energy scale with respect to MC truth jet • athena 13.0.30 + FEB cut ene_cell > 0) • DR(L2 jet – MC truth jet) < 0.07 • L2 FEB jets energy scale with respect to MC truth jet • athena 13.0.30 + FEB cut ene_cell > 100) • DR(L2 jet – MC truth jet) < 0.07 Note bigger scale on y-axis compared to distributions on Slide 13.

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