The Making of the BOL-0 @NIKHEF

1. The Making of the BOL-0 @NIKHEF • Assembly Station • Sag adjustment • Gluing BOL-0 • Temperature studies • Summary NIKHEF ATLAS MUON group: H. vdGraaf, F.Linde, G. Massaro, M. Vreeswijk, P. Werneke Marcel Vreeswijk (NIKHEF)

2. Assembly Station • Granite table: 6m x 2.5m Situation mid 99 East Z Up Y North X • 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 0.1m in Xras Marcel Vreeswijk (NIKHEF) s

3. Precision Mechanics • intrinsic accuracy better than 10um • 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) 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 West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF) s

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

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

6. Assembly Station • RASAS- the big fit The individual block deviations, 8 for Y and 4 for Z (+4 for mask orientation) can be also fitted from the observed the residuals. The final residuals can be explained by statistics (and systematics). Marcel Vreeswijk (NIKHEF) s

7. Assembly Station • RASAS -temperature stability • Aluminum expands 24um/C/m, Granite 7um/C/m • However, the relevant quantity is the relative expansion of Xplate and precision comb. East side has expansion length of 2.4m in Xras Marcel Vreeswijk (NIKHEF) s

8. Sag Compensation • Sag compensation has been used manually. • Three pressures: 2 x outer (practically equal) and inner Xplates. Sagcompen-sation tower Additional weight for safety After consistent results we adjusted the sag to obtain (almost) symmetric weight distribution Marcel Vreeswijk (NIKHEF) s

9. Sag Compensation • Xplate sag before adjustment Chamber up Chamber (upside) down Asymmetric sag Xplates, due to asymmetric weight distribution during gluing spacer -> Adjust Marcel Vreeswijk (NIKHEF) s

10. Sag Adjustment • Xplate sag after adjustment Chamber up Chamber (upside) down After sag adjustment we observe (almost) symmetric sags for chamber up and down positions Marcel Vreeswijk (NIKHEF) s

11. Assembly Station +Spacer Summary: • Assembly Station alignment good for wire position to the 10um level. • Asymmetric distribution long-beams adjusted successfully. • Sag (compensation) of cross plates understood within 20um. • Observed sag of granite table of about 30um Marcel Vreeswijk (NIKHEF) s

12. QC-Wire position • Quality Control on drift tubes, specs: • Wire position: |Y,Z|<25um 1 tube was found with R>100um. A destructive check revealed: no twister in endplug Rejection 2% Marcel Vreeswijk (NIKHEF) s

13. QC-Wire tension • Quality Control on drift tubes, specs: • Wire tension: 350gr+-5% (+batch 275gr) Rejection 5% (3%). >1 month after production, creep of the order of 1gr over >1 month Marcel Vreeswijk (NIKHEF) s

14. QC-Tube Length • Quality Control on drift tubes, specs: • Length: +-400um (Rejection 5%) • For each layer, tubes are selected on length when possible • Follow a special scheme such that gas connector fits Marcel Vreeswijk (NIKHEF) s

15. QC-Leak Rate • Quality Control on drift tubes, specs: • Leak rate: He (4 bar) 2.5 x 10-8 bl/s • (official: Ar(3 bar) 1.0 x 10-8 ) 10-1 Rejection 4% Marcel Vreeswijk (NIKHEF) s

16. QC HV Check • Quality Control on drift tubes, specs • HV 3000V , current <20nA Rejection 4% Marcel Vreeswijk (NIKHEF) s

17. Gluing BOL-0 • In the BOL-0 all tubes passed the QC. Different wire tensions are used. • Wire tension for layer 1-4: 350 gr (nominal) • For layer 5: 275 gr • layer 6: 275gr + 5 tubes with 350gr (interesting check X-ray tomograph) Marcel Vreeswijk (NIKHEF) s

18. tube tube Gluing BOL-0 • Problems: • Nozzle mounting very critical • Central glue ropes between tubes not uniform/symmetric glue Bigger central glue cilinder • Solutions: • Reduce Glue machine X speed by two (now ~10m/s) • Double amount of glue 103 (instead of 106, 2011) for central ropes which is more fluid • (keep nominal amount of glue for side ropes, 106) Glue stop for tape Marcel Vreeswijk (NIKHEF) s

19. Start glue Start glue Gluing BOL-0 • Guido laser test indicate tube heights in combs <10um. • Stability Xplates during gluing Layer 1 Yrasnik=2 x Sag Layer 1: dSag=7um Layer 2 Start glue Layer 3 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 Marcel Vreeswijk (NIKHEF) s

20. NW NE Global X Global Z, RASAS X SW SE Gluing BOL-0 • RASAS monitors Global Z • Relatively large Z movement layer 6 (spacer floats on glue?) Global Y (up) Lever arm in stacking block • Stability in Y appears very good ( for some layers the RASAS indicated problems which could be online corrected) Marcel Vreeswijk (NIKHEF) s

21. 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 down up up Cross-plate sag. For chamber up (down) positions, a negative (positive) sag points down. Marcel Vreeswijk (NIKHEF) s

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

23. Xplate Inplane Yrasnik= 2 x sag Yrasnik= 2 x sag BOL-0 Heat Studies (No flexoos in BOL-0) The BOL-0 was covered with heat blankets, producing 50W/m2 Gradient between MLs: ~4 oC Gradient over Xplates: <0.3 oC (would be larger with flexoos) Gradient over tube layers: ~0 oC Sag of Chamber: 200um /4oC= 50um/oC= acceptable Sag of xplate: 25um / 4oC = 6um/oC = acceptable Marcel Vreeswijk (NIKHEF) s

24. Summary • We have constructed BOL-0 at NIKHEF • The xplates are not equipped with flexoos. • We used araldite 103 for central ropes after we observed problems with 106 • We expect the wire positions to be within 20um(RMS) (Xray scan end of January) • However, we observed layer to layer shifts of maximal 20um. • Heat studies show a chamber sag of 50um/C and a xplate sag of 6um/C. Marcel Vreeswijk (NIKHEF) s

25. Assembly Station • Accuracy combs and sphere holders • The intrinsic accuracy of mechanics is good • The granite table has a relatively large sag of about 25um. Additional effects of 10um with light on and off (temperature gradient) • 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) West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

26. Assembly Station West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

27. Assembly Station West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

28. Gluing BOL-0 Layer 1 Layer 2 Marcel Vreeswijk (NIKHEF)

29. RASAS • RASAS- stacking The stacking has been checked using the RASAS monitors. The bare spacer has been put into A+, A-, C+ and C- orientations for the 3 stacking blocks The nominal steps are dY=26.011 um and dZ=15.017 um After a fit of the Mask-orientations (4), the residuals are shown below. Marcel Vreeswijk (NIKHEF)

30. um Assembly Station • RASAS- block deviations The fitted block deviations are within 10um as expected from measurements with a 3D coordinate machine. • The expectation values of the masks are extracted from: • CCD angles from dedicated calibration, 0.1 mrad • RASNIK measurements of relative angle from the MASK and CCD (0.1 mrad). Inmrad Marcel Vreeswijk (NIKHEF)

31. Assembly Station • RASAS -temperature stability The Xplates are made off aluminum and expand about 24um/C/m. East side has expansion length of 2.4m in Xras Marcel Vreeswijk (NIKHEF)

32. XPlate RASNIKs • The calibration (zero level) of the Xplate rasniks can be extracted from: 1) The RASNIK reading for the up and down position of the bare Xplates before gluing the spacer. Problem: old data, components touched. 2) The response for the up and down position (A+,A-) of the spacer. Problem: large effects due to large gravitational force, leading to possibly large second order effects 3) The RASNIK response for the up and down position of the airborne spacer. Problem:hysteres due to bad design of crane beams. West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

33. XPlate RASNIKs • calibration Xplate rasniks, by rotation of airborne (horizontal) spacer This method yields consistent results compared to up/down positions of the bare Xplates West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

34. In-Plane RASNIKs • The calibration of the In-Plane (Y) is extracted from data in A+, A-, C+, C- positions. • A model to account for asymmetric weight distribution over the XPs in the + and -- orientations has been used to fit the data. Data of the four in-plane systems: Data Although steps appear large and uncontrolled, the data is reasonably well described by the model (10 um) Model West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

35. In-Plane RASNIKs • Model Parameters Uncertainties 10% Implications: 1) Sag of Xplates as function of additional weigth consistent with data. FEA predicts slope of 0.56!!!!! 2) Sphere block in centre are off in height by appr. 30um as confirmed by laser+Si-sensor and also qualitatively by optical alignment tool!!!!! 3) In A+ position, when the spacer was glued, longbeam weight on outer Xplates!!!! West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

36. Sag Compensation Marcel Vreeswijk (NIKHEF)

37. Sag Compensation 0.4 bar Marcel Vreeswijk (NIKHEF)

38. Sag Compensation • Shape without sag compensation Marcel Vreeswijk (NIKHEF)

39. Sag Compensation • Shape with sag compensation Marcel Vreeswijk (NIKHEF)

40. The road to BOL-0 Marcel Vreeswijk (NIKHEF)

41. The road to BOL-0 Marcel Vreeswijk (NIKHEF)

42. QC • Quality Control on drift tubes, specs: • Wire position: |Z,Y|<25um • Wire tension: 350gr+-5% (+batch 275gr) • Leak rate: He 2.5 x 10-8 lb/s (official: Ar 1.0 x 10-8 ) • HV check: <20nA @3000V • Length: +-400um By mistake Marcel Vreeswijk (NIKHEF)

43. Gluing BOL-0 • Layer 3 Marcel Vreeswijk (NIKHEF)

44. In-Plane RASNIKs • The calibration of the In-Plane (Y) is extracted from data in A+, A-, C+, C- positions.. West side has expansion length o 0.1m in Xras Marcel Vreeswijk (NIKHEF)

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

46. Production • Production of 100 BOL chambers will start April 1th • How many people are involved? • People who do the work • People who do the visual inspections • And ‘stuurlui’ Marcel Vreeswijk (NIKHEF)