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Production and Quality Control at CERN of MWPC for the LHCb Muon System

Production and Quality Control at CERN of MWPC for the LHCb Muon System. Jean-Sebastien Graulich, CERN. The LHCb Muon System Chamber Production Quality control Conclusions. LHCb Experiment. Precision B physics experiment to study CP Violation and Rare Decay

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Production and Quality Control at CERN of MWPC for the LHCb Muon System

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  1. Production and Quality Control at CERN of MWPC for the LHCb Muon System Jean-Sebastien Graulich, CERN • The LHCb Muon System • Chamber Production • Quality control • Conclusions Jean-Sébastien Graulich

  2. LHCb Experiment • Precision B physics experiment to study CP Violation and Rare Decay • See talk N21-8 by W. Witzeling M1 M2 M3 M4 M5 Jean-Sébastien Graulich

  3. Chamber Dimension Muon System Chambers • 4 Regions/Station • Mainly MWPC • See N1-4 for GEM • 20 different chamber dimensions • 1380 chambers Jean-Sébastien Graulich

  4. Requirements • High efficiency (>99%) in 25 ns => 4 gas gaps • Efficiency uniformity => Strong mechanical specifications on the gap and the wire pitch • High rate capability (up to 0.2 MHz/cm2) for inner chambers • Good ageing properties (over 10 years) Jean-Sébastien Graulich

  5. Chamber production at CERN • CERN is in charge of the production of inner chambers for Stations 2,3,4,5 (about 10 % of the total) • “Double Sandwich” design • O-ring gas tightness Jean-Sébastien Graulich

  6. Production of M3R1 Wired Panels 35 Produced 30 Scheduled 25 20 Wired Panels 15 10 5 0 5/9/03 2/1/04 5/3/04 23/1/04 13/2/04 26/9/03 26/3/04 17/10/03 31/10/03 21/11/03 12/12/03 Time Chamber production at CERN • Production rate of 1 ch/week achieved for M3R1 (16 ch) • Upgrade to 2 ch/week in progress Jean-Sébastien Graulich

  7. HV HV HV HV Technical data Pitch: 2 mm Gap: 5 mm Wire: 30 µm,Au plated W Gas: Ar/CO2/CF4 (40/55/5) HV: 2550 V Gas Gain: 5x104 Jean-Sébastien Graulich

  8. Quality control • Wire fixation bars thickness (half gap) • Wire Pitch • Wire Tension (see poster N16-64 by D. Pinci) • Gas Leak Rate • Dark Current • Gas Gain Uniformity • Rest current (after High Rate g Irradiation) • Wire fixation bars thickness (half gap) • Wire Pitch • Wire Tension (see poster N16-64 by D. Pinci) • Gas Leak Rate • Dark Current • Gas Gain Uniformity • Rest current (after High Rate g Irradiation) Jean-Sébastien Graulich

  9. Half gap thickness • Measurement: Precise gage • Specification • Min 95 % into [2.45, 2.55] mm, all points into [2.42, 2.58] mm Jean-Sébastien Graulich

  10. Half gap thickness Distribution Jean-Sébastien Graulich

  11. Wire Pitch • Measurement: CCD Camera • Precise moving table • Telecentric Optics • Simple Pattern recognition • Specification • Min 95 % into [1.95, 2.05] mm, all points into [1.90, 2.10] Jean-Sébastien Graulich

  12. Wire Pitch Distribution Jean-Sébastien Graulich

  13. Gas gain uniformity • Measurement • Quick test with radioactive source • Safety issue • Border effect • Test station • Use 241Am source Jean-Sébastien Graulich

  14. 241Am Peak Jean-Sébastien Graulich

  15. Delay line Setup • Delay line and amplifiers developed by CBPF See N16-75 by A. Barbosa All wires connected together (Anode bar) Jean-Sébastien Graulich

  16. Delay line output • Define time window • Reconstruct ADC spectrum for events in time window • ADC peak position normalized using a precision pulser Jean-Sébastien Graulich

  17. Gas gain uniformity • Specification • Gap averages between [0.75G0, 1.25G0], • Min 95% into [0.7G0, 1.3G0], all surface into [0.5G0, 1.5G0] Jean-Sébastien Graulich

  18. Gas gain uniformity Jean-Sébastien Graulich

  19. Gas gain uniformity Jean-Sébastien Graulich

  20. Summary • CERN will produce 10% of the MWPC for the LHCb Muon System • The quality control program shows that the chambers are produced according to the specifications • A test station for gas gain uniformity has been developed and confirms the good quality of the chambers Jean-Sébastien Graulich

  21. Quality control Suppl. • Panel Planarity • Done at the panel production site • Min 95 % of the surface within 50 mm, Maxi. deviation < 100 mm • Wire Tension Measurement • All tension higher than 50 g, Max deviation < 0.1 T0 • Gas Tightness • Leak rate < 2 mbar/hour (@4 mbar Over pressure) • Measured with a reference volume in a thermally isolated box • Aging tests • test at ENEA Casaccia in June 2003 (0.5 C/cm have been accumulated in 1 month). No visible effect on current ratio, no Malter current observed. But cathode deposit. • New run is under way with reduce content of CF4 Jean-Sébastien Graulich

  22. Lear rate • Leak rate: < 2 mbar/hour (@? mbar DP) • Measured with a reference volume in a thermally isolated box TCh = TRef = Constant dV/V ~ d (DPCh-DPRef)/PCh Absolute Error on Patm cancels out Jean-Sébastien Graulich

  23. Lear rate Jean-Sébastien Graulich

  24. Same Table as for the Pitch Scan in Frequency 12 simultaneous channels Wire Tension Jean-Sébastien Graulich

  25. Wire Tension Jean-Sébastien Graulich

  26. M3R1 Production Flow Jean-Sébastien Graulich

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