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Cathode Strip Chambers Status Report

Cathode Strip Chambers Status Report. Greg Rakness University of California, Los Angeles. CMS week plenary session CERN 22 Sept. 2008. Sources of Muons Used for CSC Commissioning (I). Cosmic rays Expansion of the system from few  468 chambers

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Cathode Strip Chambers Status Report

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  1. Cathode Strip Chambers Status Report Greg Rakness University of California, Los Angeles CMS week plenary session CERN 22 Sept. 2008 G. Rakness (UCLA)

  2. Sources of Muons Used for CSC Commissioning (I) • Cosmic rays • Expansion of the system from few  468 chambers • Asynchronous muons over the full angular spectrum G. Rakness (UCLA)

  3. Intra-CSC Trigger Synchronization  Cosmic Rays Use chamber overlaps with cosmic rays to synchronize the chambers to each other on average Synchronize chambers on one endcap w.r.t. a reference chamber on that endcap  Synchronization of (most) chambers to better than 0.2bx ME+ ME D. Wang (UF) G. Rakness (UCLA) ChamberId = SectorId*100+StationId*10+CSCID

  4. ME1 ME2 ME3 ME4 ME+3 ME+4 ME+1 ME+2 Recall: Chamber Illumination with Cosmic Rays Run 57795 (CRUZET-4): Plots by A. Kubik and M. Schmitt (Northwestern) G. Rakness (UCLA)

  5. Sources of Muons Used for CSC Commissioning (II) • Single beam bunch in LHC (~2x109 protons) • Beam passes through CMS  beam dump • Synchronous muons approximately parallel to beam • Beam captured  several turns • Synchronous muons approximately parallel to beam G. Rakness (UCLA)

  6. ME+ ME x TOF  2 bx CSC “Halo Muon” Trigger  Single Beams Normal proton collisions (Beam-1) halo muon • LHC mode: both endcaps trigger simultaneously on IP muons • “Halo Muon” trigger: CSC Track Finder selects tracks with small  • Trigger on outgoing endcap (i.e., ME for Beam-1) •  Approximate timing of muons from IP • [Note: for first beams, the incoming endcap was also included in the trigger (delayed by 2bx). This is no longer true…] G. Rakness (UCLA)

  7. Chamber Illumination: Beam-2 Halo ME1 ME2 ME3 ME4 ME+1 ME+2 ME+3 ME+4 Run 62096: G. Rakness (UCLA) http://lotus.phys.northwestern.edu/~kubik/newdata/run62096/

  8. Beam Halo Event through Both Endcaps Run 62384 Event 56199 More event displays are stored athttp://www.nuhep.northwestern.edu/~schmittm/CMS/TEMP/event_displays/ G. Rakness (UCLA)

  9. Zoom in.. Most beam halo events look like this… G. Rakness (UCLA)

  10. 3-Muon Event in the CSC’s http://www.nuhep.northwestern.edu/~schmittm/CMS/RESULTS/results.html G. Rakness (UCLA)

  11. Sources of Muons Used for CSC Commissioning • Single beam bunch in LHC (~2x109 protons) • Dumps into collimators ~150m away from CMS • Synchronous “splashes” of muons + stuff G. Rakness (UCLA)

  12. Coincident with collimator dumps:“Monster” CSC events • Some numbers: • Event size  3MB (normal size ~few kB) • 160k/200k strips with data • Causes (irrecoverable) error somewhere in CSC DCC  Global DAQ Myrinet chain • Forced to stop and restart run… • Local DAQ took event with no errors • Local readout through different path… • To avoid this DAQ problem: remove CSC from Global DAQ during beam dumps into upstream collimator  Under investigation… G. Rakness (UCLA)

  13. Collimator dump  “Monster” CSC event Reconstructed segments from Local DAQ data… G. Rakness (UCLA)

  14. Data Analysis Halo muons: angles of muons and beam structure G. Rakness (UCLA)

  15. Single beam: reconstructed track angle w.r.t. the transverse plane (Separate normalization of blue and black curves  not quantitative…) Beam halo • Reasonable description of beam ON data: combination of • beam halo • cosmic rays Cosmic rays G. Rakness (UCLA) http://www.nuhep.northwestern.edu/~schmittm/CMS/RESULTS/results.html

  16. Separate Beam Halo and Cosmic Rays by Track Angle  look at the BX distribution ~ Cosmic rays ~ Beam halo Cosmic rays do not care about beam structure… Beam halo muons come in single bx number, as expected… A. Kubik (Northwestern) G. Rakness (UCLA)

  17. Beam-2: Distribution of BX values https://cmsdaq.cern.ch/elog/shift/3528 For BEAM-2 (10 Sept): CSC Halo measured to be in time with HF technical trigger… Delayed BPTX2 to be in time with HFTT and CSC Halo… For BEAM-1 (19 Sept):  “… CSC remains [the] reference…” I.Mikulec (Trigger elog 680) G. Rakness (UCLA)

  18. Data Analysis (II) Chamber performance with Beam Halo Muons G. Rakness (UCLA)

  19. Number of hits on a reconstructed segment. In MC we assume 100% efficiency for fiducial hits. A. Kubik (Northwestern) G. Rakness (UCLA)

  20. Efficiency to obtain a recHit in each given layer, for all chambers in ME+2/2 S. Stoynev (Northwestern) G. Rakness (UCLA)

  21. Towards Alignment Constants… G. Rakness (UCLA)

  22. Endcap z-positions with magnet at 0T, 3T ZCMS [mm] XSLM [mm] • First reconstructions: • ME+2,3,4 stations at B=0T, 3T • Simultaneous Rφ fit for all SLMs in ME+2, ME+3 at B=0T, 3T • Compression comparable to MTCC at equivalent magnetic field G. Gomez (Cantabria) • Integration of Barrel-Endcap-Link systems underway • Initial integrated model of link+endcap available • Provide an integrated, global muon geometry • Upload geometry in ORCON/ORCOFF to be used in reconstruction • Combine/Compare with track-based alignment G. Rakness (UCLA)

  23. Track Based Alignment J. Pivarski (Texas A&M) Use simultaneous solution of fits to residuals from overlapping regions to align chambers to each other (For details, see alignment meeting Wednesday) G. Rakness (UCLA)

  24. Summary Q: Is CSC ready for beam? Online DQM “EMU status00” plot: Green = system able to provide at least two muon stubs A: Yes (but we still have a lot to do!) G. Rakness (UCLA)

  25. Backup slides G. Rakness (UCLA)

  26. +y +z CMS +x LHC Beam Notation • LHC “Beam 1”: • Enters p5 from p4 • Traverses CMS from ME+ to ME • LHC “Beam 2”: • Enters p5 from p6 • Traverses CMS from ME to ME+ G. Rakness (UCLA)

  27. CSC Inter-Endcap Synchronization with HE Avg = 6.3 Avg = 5.2 Avg = 5.2 Avg = 5.1 Before: CRUZET-3 Accurate TTC  CCB fiber lengths implemented (Jay Hauser [UCLA]) After: CRUZET-4 G. Rakness (UCLA) ME+ and ME endcaps synchronized with each other

  28. Separate beam halo and cosmic rays by track angle (previous slide)  look at the BX distribution ~ Cosmic rays The beam halo comes mostly at a single bx, while the cosmic rays are everywhere, as expected. A. Kubik (Northwestern) ~ Beam halo (zoom-in) G. Rakness (UCLA)

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