2. Marcel Vreeswijk (NIKHEF) The Assembly of ATLAS Muon chambers @NIKHEF 2m 5m5m NIKHEF Muon Mission: 96 Barrel Outer Large (BOL) chambers Tube Production Assembly Station Assembly: Tube placing & Gluing Tomograph@CERN + test stand@NIKHEF Summary: Status & Plans

3. Marcel Vreeswijk (NIKHEF) Tube wiring + QC Drift tubes: Extruded aluminum drift tubes (3cm) Wire (50  m gold-plated tungsten) positioned by two end-plugs QC on drift tubes, specs: Wire position: |Z,Y|<25  m Wire tension=> frequency 27.2+-1.4 Hz, RMS<0.3Hz Leak rate: <2.5 10 -8 bl/s HV check: <20nA @3500V Tube Length +-0.5mm Endplug

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

5. Marcel Vreeswijk (NIKHEF) QC-Wire tension Quality Control on drift tubes, specs: Wire Frequency: 27.2 (+-1.4)Hz, RMS<0.3Hz Rejection <<1%. s Horse-shoe magnet Drift tube Principle: Lorentz force on current through wire causes vibration Frequency RMS: 0.17 Hz Tension re-measured just before gluing on table (checks creep + broken wires)

6. Marcel Vreeswijk (NIKHEF) QC-Leak Rate + HV Quality Control Leak rate: <2.5 10 -8 bl/s HV: < 20nA at 3400V s Drift tube (1% He)Vacuum chamber HV He sniffer Principle: Automated ‘Matrix’ for 80 tubes

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

8. Marcel Vreeswijk (NIKHEF) QC-HV A typical ‘Matrix’ fillA typical ‘Matrix’ fill s Gauge Tube with excess<<spec. Measure 5hrs. Average last 3hrs Tube nr Current (nA)

9. Marcel Vreeswijk (NIKHEF) Chamber Assembly West side has expansion length o 0.1m in Xras Spacer monitored by RASAS Situation mid 2000 Sphere tower with changeable block to adapt to tube layers NIKHEF Comb Frascati comb RASAS tower ‘Ear’ with sphere and RASAS-MASK In-plane mask In-plane lens Xplate longbeam s No Flexo

10. Marcel Vreeswijk (NIKHEF) ‘RASAS’ Monitors s Monitor positioning during assembly by RASAS monitor: Changeable blocks Support ‘ear’ which holds the mask The RASAS tower which holds the camera and lens xplate Block 1 Block 2 Block 3 Ypitch 26.011mm Scatter 5um Measured temperatures explain (small) drift RASAS Height (mm)

11. Marcel Vreeswijk (NIKHEF) Temperature Stability s Aluminum expands 24um/ o C/m, Granite 7um/ o C/m Under normal conditions, temperature stable within +-0.4 o C Test case: increase temp. by 1 o C: check RASAS monitors Xplate 2.4m fixed monitor granite Free to expand Raw: 50um Correct for AL 24um/ o C/m + Correct for granite 7um / o C/m

12. Marcel Vreeswijk (NIKHEF) Precision Mechanics West side has expansion length o 0.1m in Xras intrinsic accuracy better than 10um The quantities which affect the wire positions are checked and found to be precise within 10um Granite table has sag of 25um + 10um light on/off s Positioning combs and sphere holders Tools: Laser + optics (straightness combs), silicon sensor (to line up combs), Slof (height-meter), tilt-meters (check Torque), Balmonitor (dZ between multilayers )

13. Marcel Vreeswijk (NIKHEF) Assembly Station West side has expansion length o 0.1m in Xras 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 reference and non-reference side (West/East) s

14. Marcel Vreeswijk (NIKHEF) Tube Placing I s Place tubes (with clocking pins) on combs (Re-)Measure Wire Frequency Run Final-OK program IF all tubes OK, follow placing scheme FOK program ensures 72 tubes are OK Tube numbers and positions stored in dbase Specs: RMS< 0.3 Hz BOL1: 27.2+-0.7 Hz Later: 27.2+-1.4 Hz Frequency Small calibration problem

15. Marcel Vreeswijk (NIKHEF) Tube Placing II Fix gas jumpers -length differences get ‘neutralized’ Spec=-+0.5mm (FE-cards+ground foil) s

16. Marcel Vreeswijk (NIKHEF) Tube Placing QC s Vacuum on Remove clocking pins, loosen gas jumpers Check precision: Guido Laser (not automated yet) Tube Position (South) Tube Position (North) Y deviation (  m 

17. Marcel Vreeswijk (NIKHEF) Sag Compensation s ‘Dry’ Check Position spacer (+tube layers) on the table Check sag-compensation (not automated yet) Sagcompen- sation tower Additional weight for balance Actual Gluing: Chamber is pre-positioned: 1mm strips under sphere blocks+50% sag-comp. Then strips are removed + 80-90% sag-compensation Strip

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

19. Marcel Vreeswijk (NIKHEF) s Tube diameter 3cm Distance 65  m Central rope, Glu: 2019 Gluing 2 x glue units 2x3 glue nozzles tube Side rope, Glu: 2011 automated 50  m tape on Bessel points

20. Marcel Vreeswijk (NIKHEF) Gluing BOL s

21. Marcel Vreeswijk (NIKHEF) Monitoring s 3 systems monitor chamber during assembly: RASAS system (include temperature check) In-Plane system RASNIKS on cross-plates (sag) badly positioned -> action! Compensation on Monitoring system->actions not yet user friendly…. time Sag 0 50  m

22. Marcel Vreeswijk (NIKHEF) The BOL-0 s The BOL-0 was mechanically finished Dec 5th 2000 The BOL 1 was finished yesterday

23. Marcel Vreeswijk (NIKHEF) Power Outage- BOL1 s Power outage Amsterdam, during curing of layer 5 Chamber immediately covered with foil (sag compensation remained on + vacuum probably ok No indications for damage

24. Marcel Vreeswijk (NIKHEF) Gluing BOL-1 RASAS monitors SE NW SW NE Global Z, RASAS X Global X s Global Y (up) Global Z Positioning spacer appears sufficiently accurate However, differences with and without tubes (+glue) in combs --> touch (Y pitch dangerously small)

25. Marcel Vreeswijk (NIKHEF) The road to BOL-1 From 1st tube layer to 6th 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

26. Marcel Vreeswijk (NIKHEF) s Test @CERN in Tomograph (BOL0) Wire positions RMS 16  m Analysis of Martin Woudstra

27. Marcel Vreeswijk (NIKHEF) s Parameters BOL0 Zpitch wires: 30.0354  m (30.0353 expected) Ypitch wire-planes : 26.026  m (26.011 expected). Especially between two inner layers we have a larger pitch. Inelastic deformation during gluing? dY multilayers ~75  m. Hard to understand. ALL chamber scanned at CERN have deviations in this parameter?! dZ multilayers ~12  m. We expected deviations of this order, based on Balmonitor measurements Relevant Parameters (goal 20  m): RO side  =15.8  m HV side  =16.1  m

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

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

30. Marcel Vreeswijk (NIKHEF) Status & Plans Finished BOL-0 at NIKHEF (dec. 5th 2000) with high mechanical precision (16  m RMS) Quality Control Tube Assembly automated Production of tubes started May 2001 First chamber, BOL1, produced! Difficulties due to small Y pitch. Automate steps+QC chamber assembly Cosmic ray setup end 2001….

31. Marcel Vreeswijk (NIKHEF) s Expected shifts

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

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

34. Marcel Vreeswijk (NIKHEF) Gluing BOL-0 In-Plane and Xplate monitors X-inplane very stable Y-inplane alternates with chamber orientation, because off granite sag of 30um down up Cross-plate sag. For chamber up (down) positions, a negative (positive) sag points down. s

35. Marcel Vreeswijk (NIKHEF) BOL-0 Tubes press glue away? Tubes deform? Affects precision praxial platforms! Thickness Multi-layers BOL0 has tape between tubes at one side 2 layers 3 layers Much work.. s

36. Marcel Vreeswijk (NIKHEF) BOL-0 Heat Studies (No flexoos in BOL-0) s Inplane Yrasnik= 2 x sag The BOL-0 was covered with heat blankets, producing 50W/m 2 Gradient between MLs: 2.5 to 4 o C Sag of Chamber: 200um  50 to 80 um/ o C= acceptable Sag of xplate: 25um  6 to 10 um/ o C = acceptable 400um Yrasnik= 2 x sag Xplate 50um Chamber sag Xplate sag

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