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Toward Assessing HF with Beam Halo Muons & Beam-Gas Events …tuning HF when beam returns

Toward Assessing HF with Beam Halo Muons & Beam-Gas Events …tuning HF when beam returns . excerpts from US-CMS presentation 9/26/08 Michael Schmitt, NWU work of Cathode Strip Chamber muon group. Cathode Strip Chambers: CSC’s. HF-. Minus Muon Endcap. Muon group analyzed three runs

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Toward Assessing HF with Beam Halo Muons & Beam-Gas Events …tuning HF when beam returns

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  1. Toward Assessing HF with Beam Halo Muons & Beam-Gas Events …tuning HF when beam returns excerpts from US-CMS presentation 9/26/08 Michael Schmitt, NWU work of Cathode Strip Chamber muon group

  2. Cathode Strip Chambers: CSC’s HF-

  3. Minus Muon Endcap

  4. Muon group analyzed three runs • compared with beam halo MC • 62084: Wed. afternoon, beam 2 50 passes • 62096: Wed. eve, beam 2 hundreds of passes • 62232: Thur. near midnight, beam 2 captured. • Muon trigger • “hit” CSC chamber = • rechits in at least four layers out of six

  5. +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+

  6. +y +z +x Sept. 5th to 7th & 9th • Machine • Beam 2 injected IP8 • Threaded to dump in IP6 • Steered then inject and dump • Beam 1 injected IP2 • Threaded through to collimators in IP5 • CMS Tues, 9-Sept • 20 shots of Beam 1 onto collimator 150m upstream of CMS • Large CSC events require CSC (reduced HV for subsequent dumps) Traverses CMS from ME+ to ME

  7. First Events: Collimators Closed ~2 x109 protons on collimator ~150 m upstream of CMS HO,HF - dark blue; HB,HE - light blue;ECAL- pink; Muon - green; Tracker & Magnet Off ~200 muons per cm2

  8. Sept. 10th : 27 km/hr (Aymar) • Machine: • Beam 1 injected IP2 • Threaded around the machine in 1h • Trajectory steering gave 2 or 3 turns • Beam 2 injected IP8 • Threaded around the machine in 1h30 • Trajectory steering gave 2 or 3 turns • Q and Q’ trims gave a few hundred turns • CMS • Big splash events observed when beam onto collimators (as before) - 100-1000 TeV observed in ECAL-HCAL HCAL DQM gave information instantly • Halo muons observed once beam started passing through CMS with the CSCs and Calos • Prompt analysis from CSC fully reconstructed muons on real time September 10

  9. First beam: many events with a large number of hit chambers beam 1

  10. fan-like, several tracks on incident side, a little on the other. beam 1

  11. particles do not shower in muon iron yokes: muons beam 2 (early) very clean chambers…little noise

  12. many very clean events reconstruct muons through entire CMS detector

  13. events with 2 or 3 muons:

  14. muons reconstruct across 20m w/o beam alignment

  15. What do muon triggers look like in HCal? muon track does pass through the tower with the high energy measurement.

  16. Beam-Halo: HE+Muon CSC Run 62096 Event 598642 Run 62096 Event 4632 • Time distribution of HE-matched hits may be useful for rejection of halo hits in the future S. Won S. Won

  17. f h Beam Direction HF- HF+ Beam - Gas events hit HF+

  18. Summary: muon and beam gas data look good thousands of clean, well-reconstructed beam halo events are available linked with Schmitt to assess HF (with Lawson and Carleton)

  19. BACKUP

  20. Track Based Alignment J. Pivarski (Texas A&M) Use simultaneous solution of fits to residuals from overlapping regions to align chambers to each other

  21. Chamber Illumination: Beam-2 Halo ME1 ME2 ME3 ME4 ME+1 ME+2 ME+3 ME+4 Run 62096:

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