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The CMS muon system

Borislav Pavlov (University of Sofia “St. Kliment Ohridski”) for the CMS Collaboration. The CMS muon system. Introduction. Introduction CMS Muon System DT CSC RPC Moun Trigger Summary. CMS: design & construction. CMS. Muon System. System Conditions & Requirements.

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The CMS muon system

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  1. Borislav Pavlov (University of Sofia “St. Kliment Ohridski”) for the CMS Collaboration The CMS muon system

  2. Introduction • Introduction • CMS Muon System • DT • CSC • RPC • Moun Trigger • Summary B. Pavlov

  3. CMS: design & construction CMS Muon System B. Pavlov

  4. System Conditions & Requirements System Conditions Requirements • Muon identification • Muon Trigger • Unambiguous BX identification • Trigger single and multimuon with well defined pt thresholds few GeV to 100 GeV • Muon momentum measurement • Charge assignment correct to 99% confidence level up to 7 TeV • Momentum resolution • Stand alone dpt/pt = 8 - 15% at pt = 10 GeV • dpt/pt = 20 - 40% at pt = 1 TeV • Global • dpt/pt = 1 - 1.5% at pt = 10 GeV • dpt/pt = 6 - 17% at pt = 1 TeV • Barel h < 1.3 • Particle rates < 10 Hz/cm2 • Low Magnetic field • Endcap0.9 < h < 2.4 • Particle rates100-1000 Hz/cm2 • Magnetic field • Uniform axial> 3 T in ME1/1 • Highly non-uniform radial field • Up to 1 T in ME1/2 B. Pavlov

  5. MB4 MB3 MB2 MB1 CMS Muon System ¼ longitudinal slice Reduced RE system |h| < 1.6 1.6 ME4/1 restored ME3 ME2 ME1 B. Pavlov

  6. Requirements Spatial resolution (F) (per station) 75mmME1/1 and ME1/2 150mm for the others (At the trigger level< 2mm) Correct BX identification > 92% per chamber ( 99%global) Trigger Track Efficiency>99 % per chamber Resolution (per station) Position RF : 100 mm Z : 150 mm Angle:1 mrad BX identification Efficiency >98% per station Drift Tubes - DT Cathode Strip Chambers - CSC BARREL ENDCAP Resistive Plate Chambers - RPC • (Dedicated Trigger Detector) • Good timing : Resolution < 3ns (RMS), 98% within a 20ns window • Good Rate capability • Low cluster size • High efficiency > 90% per chamber ( 95% global) • rFresolution ~ 1cm B. Pavlov

  7. 42mm Independent Subunit 13 mm Wire (Gas tightness, HV, Front End) Electrode Strip Cathode Al Strips Mylar F SL q SL Honeycomb F SL Drift Tube Chambers 4 Layers = 1 Superlayer (SL) GAS: Ar/CO2 (85/15) HV: Wires 3600 V Strips 1800 V I-beams -1200 V Tmax: 380 ns Single Wire 100mm F Drift Velocity : ~ 55mm/ns Resolution : < 300 mm 150mm q B. Pavlov

  8. DT Local trigger - Bunch Track Identifier (BTI) Based on meantime technique MT is independent on the track angle and position MT1 = 0.5 * (T1 + T3) + T2 MT2 = 0.5 * (T2 + T4) + T3 • Signals are shifted in registers • BTI looks for coincidence every clock period • hits in ≥ 3 planes • At a time T=Tmax after muon crossing • the drift times are aligned i.e. • the hits form an image of the muon track Allows effective bunch crossing identification B. Pavlov

  9. 60 MB1 3SL 2 RPC ~2.0 x 2.54 m2 960kg 60 MB2 3SL 2 RPC ~2.5 x 2.54 m2 1200kg 60 MB3 3SL 1 RPC ~3.0 x 2.54 m2 1300kg 40 MB4 2SL 1 RPC ~4.2 x 2.54 m2 1800kg 10 MB1 2SL 1 RPC 10 MB2 2SL 1 RPC 10 MB3 2SL 1 RPC 4 3 5 2 6 1 7 12 8 11 9 10 Barrel Muon DT The Barrel Muon system comprises 250 chambers In 7 flavors for 5 wheels Total 1700 m2 B. Pavlov

  10. CIEMAT AACHEN Production sites DT Production Sites TORINO LEGNARO B. Pavlov

  11. Cosmic Event in a CMS sector B. Pavlov

  12. Magnetic field = 1T Cosmic muon trajectory in the barrel DTs http://cms.cern.ch/ B. Pavlov

  13. Wire spacing ~3mm Gas:Ar(40%) + CO2 (50%)+CF4(10%) HV wires ~ 3.6 kV Gas gap 9.5mm Cathode Strip Chambers (CSC) Trapezoidal Chambers (100 or 200 in F), 6 layers Radial cathode strips – measureF(75-150 mm) Wires orthogonal to strips Precise timing measurement (BX) - ~4.5 ns Coarse measurement of the radial position (16-54 mm) B. Pavlov

  14. CSC Outer section of 4’th station staged 6 planes per chamber 468 chambers 6000 m2sensitive area 2 Million wires 220 K cathode channels 1 chamber ~ 1000 readout chanels ME1/1 –special design Inserted in endcap Calorimeter support B. Pavlov

  15. PNPI – 114 assembled IHEP – 148 assembled CSC production sites Chamber with on-board electronics Dubna FNAL – 148assembled Dubna – 72 assembled B. Pavlov

  16. ISR FAST Site Final Testing before installation at SX5 B. Pavlov

  17. CSCs on YE+1 and YE-1 14 June, 2006 YE+1 YE-1 B. Pavlov

  18. Chamber commissioning at SX5 using test pulses and cosmic rays Cosmic Ray First particles detected by installed “CMS” subsystem!! B. Pavlov

  19. Resistive Plate Chambers Resistive Plates – bakelite with bulk resistivity (2 ± 1).1010Ωcm Gas gap (2mm ± 20μm wide) Gas mixture, containing 96% C2H2F4(Freon), 3,5 % isobutan, SF6 – 0,5 % Graphite electrodeswith resistivity 300 kΩ / cm Insulating PET film (0.3 mm thick) Detecting copper strips 40μm thick,2–4 cm wide and 1250 mm long Spacers (cylinders with diameter 10 mm and height 2mm) Copper shielding Linseed oil treatment B. Pavlov

  20. RPC - Principle of Action B. Pavlov

  21. CMS RPC Fast detectorsfor thefirst level triggerof the experiment Considerablygood space resolution Able to work in areas with background~ 10 3 Hz/cm 2 Price – as low as possible Requirements Time resolution≤ 1.8 ns (98 % within 20 ns) Efficiency> 95 % Rate capability≤ 1kHz/cm2 • Average cluster size < 2 strips • Number of streamers< 10% • Operation plateau> 300V • Power consumption2-3 W/m2 • Operational voltage 8.5 –10 kV B. Pavlov

  22. Main Barrel RPC Types Length: 2.455 m Width: 1.5, 2.0 , 2.5 m Pitch: 40.8, 40.6, 41.0 mm # Strips for Gap: 48, 36, 48, 60 Left Right RB4 Width: 1.48 m Pitch: 34.8 mm # Strips for Gap: 42 Left Right RB3 Width: 1.5, 2.0 , 2.5 m Pitch: 27.3, 29.3 mm # Strips for Gap: 84, 90 Out RB2 In Width: 1.5, 2.0 , 2.5 m Pitch: 22.7, 24.3 mm # Strips for Gap: 84, 90 Out RB1 In B. Pavlov

  23. Barrel RPC Production ISR Chambersproduction and quality certification involve several steps. Pavia Sofia GT Bari GT Single gap Double gap HT Chamberassembling Sites Chambertest Sites RB1 in Pavia RB2 & RB4 in Bari RB3 in Sofia (& Bari) 120 RB1 at HT 240 RB2 and RB4 at GT 120 RB3 in Sofia (& Bari) B. Pavlov

  24. Bari Sofia RPC Production Sites Pavia B. Pavlov

  25. RPC tests at ISR ISR RPC storage and test area B. Pavlov

  26. Installation of DT and RPC At ISR Coupling RPC to DT Fast test Transportation to SX5( CMS surface hall) At SX5 Installation in the CMS Detector Started in June B. Pavlov

  27. Cosmic event in the RPCs B. Pavlov

  28. CERN Project Co-ordination ISR Assembly Station China Korea Pakistan Gap production Korea Front-end electronics Pakistan Endcap RPC B. Pavlov

  29. Korea Pakistan RPC Production Sites ISR Lab Test of first chambers B. Pavlov

  30. Muon Trigger B. Pavlov

  31. Summary CMS Muon System – big international project - 3 Continents Magnet test and Cosmic runs are going now DT Chambers DT production ended (266 out of 250) Delivered to CERN - 262 Installed - 146 CSC Chambers Production finished (496 out of 468 CSCs) Delivered to CERN – 495 Installed - 432 RPC Chambers 460 (out of 480) barrel RPCs assembled. End of production - December. Delivered to CERN – 380 Installed - 278 Endcap RPC – YE+1 and YE+2 installed Endcap RPC - YE+3 and YE-1 will be installed until the end of the year B. Pavlov

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