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  • Количество слайдов: 28

The Making of ATLAS Muon chambers @NIKHEF • • • The NIKHEF Muon Mission The Making of ATLAS Muon chambers @NIKHEF • • • The NIKHEF Muon Mission Drift tube wiring Chamber assembly X-ray scan of BOL-0 at CERN Status and Plans Marcel Vreeswijk (NIKHEF)

NIKHEF Muon Mission • 5 m 2 m BOL=spacer+2 x 3 drift tube layers+ NIKHEF Muon Mission • 5 m 2 m BOL=spacer+2 x 3 drift tube layers+ In-Plane alignment Construct: 96 Barrel Outer Large (BOL) chambers High Mechanical Precision: 20 mm RMS on wire positions This talk: has expansion length o 0. 1 m in Xras West side BOL-0 and Serial Production Marcel Vreeswijk (NIKHEF) s

Tube wiring + QC • Drift tubes: • Extruded aluminum drift tubes (3 cm) Tube wiring + QC • Drift tubes: • Extruded aluminum drift tubes (3 cm) • Wire (50 mm gold-plated tungsten) positioned by two end-plugs Endplug QC on drift tubes, specs: • Wire position: |Z, Y|<25 mm • Wire tension=> frequency 27. 2+-1. 4 Hz, RMS<0. 3 Hz • Leak rate: <2. 5 10 -8 bl/s • HV check: <20 n. A @3500 V Marcel Vreeswijk (NIKHEF)

QC-Wire position Drift Tube Wire position Spec: |Y, Z|<25 mm Coil For BOL-1 All QC-Wire position Drift Tube Wire position Spec: |Y, Z|<25 mm Coil For BOL-1 All tubes checked In future: Fast pre-check endplug End. Plug RMS: ~6 mm Rejection <<1%: 2 tubes with Z> 50 um (1 checked: no twister) cut No twister to position wire Marcel Vreeswijk (NIKHEF) s

QC-Wire tension Quality Control on drift tubes, specs: • Wire Frequency: 27. 2 (+-1. QC-Wire tension Quality Control on drift tubes, specs: • Wire Frequency: 27. 2 (+-1. 4)Hz, RMS<0. 3 Hz Principle: Lorentz force Drift tube on current through wire causes vibration Frequency RMS: 0. 17 Hz Horse-shoe magnet Tension re-measured just before gluing on table (checks creep + broken wires) Rejection <<1%. Marcel Vreeswijk (NIKHEF) s

QC-Leak Rate + HV Quality Control • Leak rate: <2. 5 10 -8 bl/s QC-Leak Rate + HV Quality Control • Leak rate: <2. 5 10 -8 bl/s • HV: < 20 n. A at 3400 V Principle: HV Drift tube (1% He) Vacuum chamber He sniffer Automated ‘Matrix’ for 80 tubes Marcel Vreeswijk (NIKHEF) s

QC-Leak Rate Leak-rate spec Leak rate is low: from 3 bar to 2 bar QC-Leak Rate Leak-rate spec Leak rate is low: from 3 bar to 2 bar takes several years!! Rejection 1% (!) 10 -6 bl/s 3 tubes inspected: • 1 physical hole in aluminum • 2 ‘dust’ on O-ring Marcel Vreeswijk (NIKHEF) s

QC-HV • A typical ‘Matrix’ fill Current (n. A) Measure 5 hrs. Average last QC-HV • A typical ‘Matrix’ fill Current (n. A) Measure 5 hrs. Average last 3 hrs Tube with excess<

Chamber Assembly • Spacer monitored by RASAS No Flexo lo ng Situation mid 2000 Chamber Assembly • Spacer monitored by RASAS No Flexo lo ng Situation mid 2000 In-plane lens NIKHEF Comb be am RASAS tower Xplate In-plane mask Frascati comb ‘Ear’ with sphere and RASAS-MASK Sphere tower with changeable block to adapt expansion length o 0. 1 m in Xras West side has to tube layers Marcel Vreeswijk (NIKHEF) s

‘RASAS’ Monitors Monitor positioning during assembly by RASAS monitor: Support ‘ear’ which holds the ‘RASAS’ Monitors Monitor positioning during assembly by RASAS monitor: Support ‘ear’ which holds the mask xplate Changeable blocks Block 3 The RASAS tower which holds the camera and lens Block 2 Ypitch 26. 011 mm Block 1 Scatter 5 um Measured temperatures explain (small) drift Marcel Vreeswijk (NIKHEF) s

Gluing BOL-0 2 x glue units 2 x 3 glue nozzles Tube diameter 3 Gluing BOL-0 2 x glue units 2 x 3 glue nozzles Tube diameter 3 cm Distance 65 mm Side rope Central rope • Tube layer 1 central ropes • Spacer glued on layer 1 • Tube layer 2 central ropes • Spacer+1 glued on layer 2 • Tube layer 3 central+side ropes tube • Spacer+1+2 on layer 3 • etc…. tube Marcel Vreeswijk (NIKHEF) s

Sag Compensation • Residue: order 10 mm • Own weight leads to large sag Sag Compensation • Residue: order 10 mm • Own weight leads to large sag of xplates • Compensate (at Bessel points) with pneumatic system • Need typical P=3 bar (8 towers) to carry chamber (150 kg) Sagcompensation tower Additional weight for balance Marcel Vreeswijk (NIKHEF) s

Gluing BOL-0 Glue: Days needed 1 Glue Spacer 1 1 st layer+platforms 1 spacer Gluing BOL-0 Glue: Days needed 1 Glue Spacer 1 1 st layer+platforms 1 spacer on 1 st 1 2 nd layer+spacer 4 layers Total <10 days Marcel Vreeswijk (NIKHEF) s

The BOL-0 was mechanically finished Dec 5 th 2000 Next, studies: • X-ray scan The BOL-0 was mechanically finished Dec 5 th 2000 Next, studies: • X-ray scan Marcel Vreeswijk (NIKHEF) s

Test @CERN in Tomograph Marcel Vreeswijk (NIKHEF) s Test @CERN in Tomograph Marcel Vreeswijk (NIKHEF) s

Test @CERN in Tomograph Analysis of Martin Woudstra Wire positions RMS 16 mm Marcel Test @CERN in Tomograph Analysis of Martin Woudstra Wire positions RMS 16 mm Marcel Vreeswijk (NIKHEF) s

Test stand Like cosmic ray setup at CERN (shutdown in 2000) DAT CHA Test Test stand Like cosmic ray setup at CERN (shutdown in 2000) DAT CHA Test of alignment principle with prototype muon sector, using cosmic tracks --> 10 mm on sagitta Marcel Vreeswijk (NIKHEF) s

Test stand @NIKHEF Tests five chambers using cosmic rays (end 2001) • Checks wire Test stand @NIKHEF Tests five chambers using cosmic rays (end 2001) • Checks wire positions • Checks DCS + DAQ Trigger modules, consisting of 50 cm iron, with two layers scintillator. Ecut>1 Ge. V Expected rate: 100 Hz Marcel Vreeswijk (NIKHEF) s

Status and Plans • Finished BOL-0 at NIKHEF (dec. 5 th 2000) with high Status and Plans • Finished BOL-0 at NIKHEF (dec. 5 th 2000) with high mechanical precision (16 mm RMS) • Quality Control automated • Production of tubes started May 2001 • Now: Produce first chamber • Expect to finalize 10 chambers by end 2001 • Produce 1 chamber/2 weeks: 24 chambers/year -> finish summer 2005 • Late 2002, evaluate need to speed up chamber production (work weekends and/or two gluing steps/day) • Cosmic ray setup operational end 2001 Marcel Vreeswijk (NIKHEF)

Sag Compensation • Xplate sag before and after compensation Chamber up Chamber (upside) down Sag Compensation • Xplate sag before and after compensation Chamber up Chamber (upside) down Understood within +-10 mm After sag adjustment we observe (almost) symmetric sags for chamber up and down positions-> no stress Marcel Vreeswijk (NIKHEF) s

Gluing BOL-0 • RASAS monitors NW NE Global X Global Z, RASAS X SW Gluing BOL-0 • RASAS monitors NW NE Global X Global Z, RASAS X SW Global Z SE • Relatively large Z movement layer 6 (spacer floats on glue? ) Global Y (up) Lever arm in stacking block • Stability in Y appears good Marcel Vreeswijk (NIKHEF) s

Temperature Stability • Aluminum expands 24 um/ o. C/m, Granite 7 um/ o. C/m Temperature Stability • Aluminum expands 24 um/ o. C/m, Granite 7 um/ o. C/m • Under normal conditions, temperature stable within +-0. 4 o. C • Test case: increase temp. by 1 o. C: check RASAS monitors Free to expand Xplate 2. 4 m fixed monitor granite Raw: 50 um Correct for AL 24 um/ o. C/m + Correct for granite 7 um/ o. C/m Marcel Vreeswijk (NIKHEF) s

Assembly Station • Granite table: 6 m x 2. 5 m Situation mid 99 Assembly Station • Granite table: 6 m x 2. 5 m Situation mid 99 North X East Z Up Y • Three bare Cross-Plates are positioned on the station, carried by sphere holders • The combs which will support the tubes are also visible • In the background: wiring station, Quality Control setup(s) West side has expansion length o 0. 1 m in Xras Marcel Vreeswijk (NIKHEF) s

Alignment Relative measurement of three points. Accuracy the coded mask ~ 100 um block Alignment Relative measurement of three points. Accuracy the coded mask ~ 100 um block size 1 um In-Plane Projective alignment • Alignment scheme: West side has expansion length o 0. 1 m in Xras Marcel Vreeswijk (NIKHEF) s

RASNIK • Components provided by NIKHEF Light source + mask Image sensor Lens + RASNIK • Components provided by NIKHEF Light source + mask Image sensor Lens + holder Marcel Vreeswijk (NIKHEF) s

ATLAS-Muon • Magnet system: air core toroid, • End cap toroid constructed in the ATLAS-Muon • Magnet system: air core toroid, • End cap toroid constructed in the Netherlands B field measurement by Hall probes (on CAN bus) designed and provided by NIKHEF calibration 0. 02% |BHall| - |Bcoil| West side has expansion length o 0. 1 m in Xras Marcel Vreeswijk (NIKHEF) s

QC-Leak Rate Quality Control on drift tubes, specs: • Leak rate: He (4 bar) QC-Leak Rate Quality Control on drift tubes, specs: • Leak rate: He (4 bar) 2. 5 x 10 -8 bl/s HV (future) Drift tube (1% He) Vacuum chamber cut He sniffer Leak rate is low: from 4 bar to 2 bar takes several years!! Rejection 4% Marcel Vreeswijk (NIKHEF) s

BOL-0 Heat Studies (No flexoos in BOL-0) The BOL-0 was covered with heat blankets, BOL-0 Heat Studies (No flexoos in BOL-0) The BOL-0 was covered with heat blankets, producing 50 W/m 2 Xplate Inplane 50 um 400 um Yrasnik= 2 x sag g Chamber sag at pl X a es Gradient between MLs: 2. 5 to 4 o. C Sag of Chamber: 200 um Sag of xplate: 25 um 6 to 50 to 80 um/o. C= acceptable 10 um/o. C = acceptable Marcel Vreeswijk (NIKHEF) s