The Assembly of ATLAS Muon chambers NIKHEF

The Assembly of ATLAS Muon chambers @NIKHEF • • • The NIKHEF Muon Mission Chamber assembly Assembly QA Assembly QC Summary, Status and Plans Marcel Vreeswijk (NIKHEF)

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: West side BOL-1 and length o Production BOL-0, has expansion Serial 0. 1 m in Xras Marcel Vreeswijk (NIKHEF) s

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

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 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

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

Tube Placing Start with QC tubes Procedure Place tubes on combs (Re-)Measure Wire Frequency Run Final-OK program IF all tubes OK, follow placing scheme Marcel Vreeswijk (NIKHEF) s

Glu Preparation Marcel Vreeswijk (NIKHEF) s

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 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

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

The road to BOL-0 Marcel Vreeswijk (NIKHEF)

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

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

Gluing BOL-0 • Guido laser test indicate tube heights in combs <10 um. • Stability Xplates during gluing Layer 1 Yrasnik=2 x Sag Layer 1: d. Sag=7 um Layer 2 Start glue Layer 2: d. Sag=10 um Layer 3 Start glue • The sag of the xplates in layer 1 and 2 change in time. Glue crimp? Temperature? • Layer 3, 4, 5, 6: Sag stable Marcel Vreeswijk (NIKHEF) s

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

The road to BOL-0 Marcel Vreeswijk (NIKHEF)

The road to BOL-1 • From 1 st tube layer to 6 th tube layer took 14 days (spacer not counted) • With optimal/parallel preparation the present scheme would allow a 7 day production cycle • Infrastructure and manpower-> 10 working-days/chamber Marcel Vreeswijk (NIKHEF)

Test @CERN in Tomograph Marcel Vreeswijk (NIKHEF) s

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 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 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

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

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)

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

Precision Mechanics • intrinsic accuracy better than 10 um Positioning combs and sphere holders Tools: • Laser + optics (straightness combs), • silicon sensor (to line up combs), • Slof (height-meter), • tilt-meters (check Torque), • Balmonitor (d. Z between multilayers) The quantities which affect the wire positions are checked and found to be precise within 10 um Granite table has sag of 25 um + 10 um light on/off West side has expansion length o 0. 1 m in Xras Marcel Vreeswijk (NIKHEF) s

Assembly Station • The Balmonitor is a Cross-Plate equipped with lenses. Each lens is combined with a ‘fork’ on the combs to form a RASNIK system • The Balmonitor measures the Z and Y difference between Sphere tower and Comb between North and South. (Z difference between Multilayers) • Additionally the Balmonitor is used to check for height difference between sphere towers at the West side has expansion length o 0. 1 m in Xras reference and non-reference side (West/East) Marcel Vreeswijk (NIKHEF) s

Gluing BOL-0 • Result for side (106) and central (103) ropes Central rope tube Central rope, sometimes bad (stability glue unit? ) Marcel Vreeswijk (NIKHEF)