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Muon Detection & Measurement @ SLHC

Muon Detection & Measurement @ SLHC. CMS. ATLAS. Frank Taylor MIT Int’nl Workshop on Future Hadron Colliders FNAL October 16-18, 2003. Critical Issues. Rate demand on tracking & trigger technologies Occupancy vs. pattern recognition Ghost tracks & Track Matching between ID & Muons

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Muon Detection & Measurement @ SLHC

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  1. Muon Detection & Measurement @ SLHC CMS ATLAS Frank Taylor MIT Int’nl Workshop on Future Hadron Colliders FNAL October 16-18, 2003

  2. Critical Issues • Rate demand on tracking & trigger technologies • Occupancy vs. pattern recognition • Ghost tracks & Track Matching between ID & Muons • Trigger PT – resolution & Rate • Stability of chamber parameters under rate • Space charge effects, R-T relation affected • Spatial resolution vs. rate • Beam crossing timing • Longevity • Chambers & Electronics (Rad Hard & SE Upsets) • Shielding size & activation • Thick enough • Personnel access F.E. Taylor

  3. SLHC Environment ~ 600 @ RHIC F.E. Taylor

  4. CMS Muon System • Three types of gaseous detectors: • Drift Tubes in Barrel (DTs) • Cathode Strip Chambers in Endcaps (CSCs) • Resistive Plate Chambers (RPCs) in both barrel and endcaps • Coverage: || < 2.4 F.E. Taylor

  5. ATLAS Muon System • Muon Spectrometer: • Toroidal magnetic field: <B> = 0.4 T • Air-core coils • 3 detector stations • - cylindrical in barrel • -wheels for endcaps • Coverage: || < 2.7 • Technologies: • Fast trigger chambers: TGC,RPC • High resolution tracking detectors: MDT,CSC F.E. Taylor

  6. CMS Barrel Drift Tube Chambers Drift time ~ 320 to 400 ns F.E. Taylor

  7. Monitored Drift Tube Chambers (MDT) Barrel • 6 / 8 drift tube layers,arranged in • 2 multilayersglued to a spacer frame • Length: 1 – 6 m, width: 1 – 2 m • Gas: Ar:CO2 (93:7) @ 3 bar • Maximum drift time ~ 600 ns End Cap F.E. Taylor

  8. CMS CSC Endcap • 468 CSCs of 7 different types/sizes • > 2,000,000 wires (50 mm) • 6,000 m2 sensitive area • 1 kHz/cm2 rates • 2 mm and 4 ns resolution/CSC (L1-trigger) • 100 m resolution/CSC (offline) Charge integration time ~ 400 ns F.E. Taylor

  9. CMS f precision coordinate Drift Tubes (DT) In barrel 0<|h|<1 40 mm x 13 mm cell 2nd coordinate Beam crossing time t ~ 400 ns Cathode Strip Chambers (CSC) in endcap 1<|h|<2.4 2-D readout f strips 3 to 16 mm ATLAS q precision coordinate Monitored Drift Tubes (MDT) in Barrel & Endcap 0<|h|<2.7 except 1st layer 30 mm dia. cell t ~ 600 ns 2nd Coordinate RPC in barrel & TGC in endcap CSC inner endcap layer 2.0<|h|<2.7 2-D readout q strips 3 mm f strips ~ 10 mm Gas Detectors-Tracking Technologies F.E. Taylor

  10. ATLAS l vs. h Design Criterion m-rate dominated by prompt & decays in inner tracker volume CMS 10 to 15 l in front of M1 station F.E. Taylor

  11. Neutron Flux – ATLAS @ 1034 cm-2 s-1 2-10 mSv/h in access 4 20 100 • (MDT) ~ 5x10-4 e (CSC) ~ 2x10-4 • (RPC) ~ 5x10-4 e(TGC) ~ 10-3 N neutrons (kHz/cm2) @ 300 keV but strongly energy dependent F.E. Taylor

  12. Photon Flux – ATLAS @ 1034 cm-2 s-1 2 4 20 • (MDT) ~ 8x10-3 e (CSC) ~ 5x10-3 • (RPC) ~ 5x10-3 e(TGC) ~ 5x10-3 N photons (kHz/cm2) F.E. Taylor

  13. Rate ‘Cross section’ vs. PT - ATLAS m m m mb/GeV F.E. Taylor

  14. Muon Chamber Counting Rate – ATLAS @ 1034 gsare dominate component @ 1035 -> max rate ~ 10 kHz/cm2 MDT ~ 0.5 C/cm-yr Calorimeter Electronics “Chimney” TDR now smaller F.E. Taylor

  15. Muon Track in ATLAS 5 X Bkg. @ 1034 Occup. ~ 10 % F.E. Taylor

  16. Precision Tracking Chamber Occupancy L ~ 5x1034 cm-2 s-1 MDT & CSC 2X larger ~ acceptable 10X larger very uncomfortable and something has to done Occupancy (%) F.E. Taylor

  17. MDT Performance under Rate single tube resolution vs. drift radius , Ar:CO2(93:7), 3 bar Degradation due to space charge fluctuations F.E. Taylor

  18. Luminosity effects HZZ  ee event with MH= 300 GeV for different luminosities 1032 cm-2s-1 1033 cm-2s-1 Praha July 2003 1034 cm-2s-1 1035 cm-2s-1 F.E. Taylor SLHC prospects Albert De Roeck (CERN)

  19. Pattern Recognition to be Studied • Track matching between ID & Muon System • Spatial matching • 1/P matching • Second Coordinate & Ghost tracks • Muon Track Isolation • Decay ms from b, c, p, K • Dominate Bkg from H -> ZZ* -> mmmm is tt and Zbb • Isolation cut DR = (Dh2 + Df2)1/2 < Rmax F.E. Taylor

  20. Trigger Issues • Resolution • Sharpness of Pt turn-on • Rate • Reals & Accidentals • Possible to raise threshold ? • Resolution & Accidentals permitting F.E. Taylor

  21. CMS Trigger primitive developed from track curvature in muon system of DT, CSC, RPC F.E. Taylor

  22. ATLAS Muon Trigger Primitives F.E. Taylor

  23. RPC – used in both CMS & ATLAS 3 mm gap • Intrinsically fast response ~ 3 ns • R&D effort to understand long term characteristics • Rate handling depends on electrode resistivity • r observed to increase by 2 orders of magnitude F.E. Taylor

  24. Thin Gap Chambers (TGC) in ATLAS Not to scale • Small drift distance & close wire spacing t ~ 25 ns • 1.8 mm wire spacing, 1.4 mm anode - cathode • Has to use a heavily quenched gas F.E. Taylor

  25. TGC Timing TGC inefficient for 12.5 ns beam crossing interval F.E. Taylor

  26. Trigger PT Resolution e@ turn-on important F.E. Taylor

  27. Trigger Resolution & Rate Accidentals X 10 Accidentals 6 GeV @ 1035 (100 nb-1 s-1 ) Trig Rate ~ 104 Hz & mostly ‘real’ if accidental rate nominal – higher thresholds ~ larger fraction of accidentals 20 GeV 20 GeV 6 GeV F.E. Taylor

  28. Conclusions • R&D Program • Experience with LHC running • Calibration of shielding & Backgrounds • Identify the ‘real’ problems • Detector issues clear at this time (2003) • Faster & More Rad-Hard trigger technology needed • RPCs (present design) will not survive @ 1035 • TGCs need to be faster … perhaps possible • Gaseous detectors only practical way to cover large area of muon system (DT, MDT & CSC) Area ~ 104 m2 • Better test data needed on resol’n vs. rate • Bkg. g and neutron efficiencies • Search for faster gas => smaller drift time • Drive technologies to 1035 conditions • Technologies DT, MDT & CSC not precluded F.E. Taylor

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