Marcel Vreeswijk (NIKHEF)
The Assembly of ATLAS The Assembly of ATLAS Muon chambers @NIKHEFMuon chambers @NIKHEF
The Assembly of ATLAS The Assembly of ATLAS Muon chambers @NIKHEFMuon chambers @NIKHEF
2m
5m
NIKHEF Muon Mission: 96 Barrel Outer Large (BOL) chambers
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
Marcel Vreeswijk (NIKHEF)
Tube wiring + QC
•Drift tubes:•Extruded aluminum drift tubes (3cm)
•Wire (50m gold-plated tungsten) positioned by two end-plugs
QC on drift tubes, specs:•Wire position: |Z,Y|<25m •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
Marcel Vreeswijk (NIKHEF)
QC-Wire position
Wire position Spec: |Y,Z|<25m
s
EndPlug
Drift Tube
Coil
Rejection <<1%:2 tubes with Z> 50um (1 checked: no twister)
cut cut
For BOL-1All tubes checked
In future: Fast pre-check endplug
No twisterto positionwire
RMS: ~6m
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
FrequencyRMS: 0.17 Hz
Tension re-measured just before gluing on table(checks creep + broken wires)
Marcel Vreeswijk (NIKHEF)
QC-Leak Rate + HVQuality 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
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 2bartakes several years!!
10-6 bl/s
Leak-rate
spec
Marcel Vreeswijk (NIKHEF)
QC-HV• A typical ‘Matrix’ fillA typical ‘Matrix’ fill
s
Tubbies: Leak current 30-5-2001, av. laatste 3 metingen
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
nA
Gauge
Tube withexcess<<spec.Measure 5hrs. Average last 3hrs
Tube nr
Cur
rent
(nA
)
Current as function of time
0
1
2
3
4
5
6
30-05-0118:00
30-05-0119:12
30-05-0120:24
30-05-0121:36
30-05-0122:48
31-05-010:00
Date & Time
tub
e c
urr
en
t (n
A)
Tube A1
Tube A2
Marcel Vreeswijk (NIKHEF)
Chamber Assembly
West side has expansion length o 0.1m in Xras
• Spacer monitored by RASASSituation mid 2000
Sphere tower with changeable block to adapt to tube layers
NIKHEF Comb
Frascati comb
RASAStower
‘Ear’ with sphere and RASAS-MASK
In-plane mask
In-plane lens
Xplate
longbeam
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No Flexo
Marcel Vreeswijk (NIKHEF)
‘RASAS’ Monitors
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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
RA
SA
S H
eigh
t (m
m)
Marcel Vreeswijk (NIKHEF)
Temperature Stability
s
•Aluminum expands 24um/ oC/m, Granite 7um/ oC/m
•Under normal conditions, temperature stable within +-0.4 oC
•Test case: increase temp. by 1 oC: check RASAS monitors
Xplate 2.4mfixed monitorgranite
Free toexpand
Raw: 50um
Correct for AL 24um/ oC/m
+ Correct for granite 7um/ oC/m
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 10umGranite 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)
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
Marcel Vreeswijk (NIKHEF)
Tube Placing I
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Place tubes (with clocking pins) on combs (Re-)Measure Wire FrequencyRun Final-OK programIF all tubes OK, follow placing scheme
FOK program ensures 72 tubes are OK
Tube numbers and positions stored in dbase
Specs:RMS< 0.3 HzBOL1: 27.2+-0.7 HzLater: 27.2+-1.4 Hz
Frequency
Small calibration problem
Marcel Vreeswijk (NIKHEF)
Tube Placing II
Fix gas jumpers-length differences get ‘neutralized’Spec=-+0.5mm (FE-cards+ground foil)
s
Marcel Vreeswijk (NIKHEF)
Tube Placing QC
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Vacuum onRemove clocking pins, loosen gas jumpersCheck precision: Guido Laser (not automated yet)
Tube Position (South)
Tube Position (North)
Y d
evia
tion
(m
Marcel Vreeswijk (NIKHEF)
Sag Compensation
s
‘Dry’ CheckPosition spacer (+tube layers) on the tableCheck sag-compensation (not automated yet)
Sagcompen-sation tower
Additionalweight for balance
BOLP (bar) South Mid NorthL1 2 1.3 2L2 2.5 1.7 2.5L3 3 2.1 3L4 3.5 2.5 3.5L5 4 2.9 4L6 4.5 3.3 4.5
Gauge Actual Gluing:Chamber is pre-positioned: 1mm strips under sphere blocks+50% sag-comp.
Then strips are removed + 80-90% sag-compensation
Strip
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
Understoodwithin +-10m
Marcel Vreeswijk (NIKHEF) s
Tube diameter 3cmDistance 65m
Central rope,Glu: 2019
Gluing2 x glue units2x3 glue nozzles
tube
tube tube
tubetube
Side rope,Glu: 2011
automated
50m tape on
Bessel points
Marcel Vreeswijk (NIKHEF)
Gluing BOL
s
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
50m
Marcel Vreeswijk (NIKHEF)
The BOL-0
s
The BOL-0 was mechanically
finished Dec 5th 2000
The BOL 1 was finished yesterday
Marcel Vreeswijk (NIKHEF)
Power Outage- BOL1
s
Power outage Amsterdam, during curing of layer 5Chamber immediately covered with foil (sag compensation remained on + vacuum probably okNo indications for damage
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)
Marcel Vreeswijk (NIKHEF)
The road to BOL-1Date Item Comment15/06 Glu Spacer Use sagcompensation26/06 Layer 1-half Problem glu-machine27/06 Layer 1-rest Ok27/06 Praxial Platforms No measurements…..
27/06 Spacer on 1st layer Ok28/06 Preparations29/06 2nd layer + spacer Spacer+1st+2nd layer ok01/07 Preparations02/07 Preparations03/07 3rd layer Spacer+3 layers ok04/07 4th layer Spacer+4 layers ok05/07 5th layer Spacer+5 layers ok06/07 Preparations09/07 6th layer Mechanically finishedJuly Gas manifolds +Protective covers>July Xray tomo@CERN>2001??? FE-Electronics
•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
Marcel Vreeswijk (NIKHEF) s
Test @CERN inTomograph (BOL0)
Wire positionsRMS 16m
Analysis of Martin Woudstra
Marcel Vreeswijk (NIKHEF) s
Parameters BOL0
Zpitch wires: 30.0354m (30.0353 expected)
Ypitch wire-planes:
26.026m (26.011 expected). Especially between two inner layers we have a larger pitch. Inelastic deformation during gluing?
dY multilayers ~75m.Hard to understand. ALL chamber scanned at CERN have deviations in this parameter?!
dZ multilayers ~12m. We expected deviations of this order, based on Balmonitor measurements
•Relevant Parameters (goal 20m):
RO side =15.8m HV side =16.1m
Marcel Vreeswijk (NIKHEF)
Test stand
s
DATCHADATCHA
Like cosmic ray setup at CERN (shutdown in 2000)
Test of alignment principle with prototype muon sector,using cosmic tracks --> 10m on sagitta
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>1GeVExpected rate: 100Hz
Marcel Vreeswijk (NIKHEF)
Status & Plans
• Finished BOL-0 at NIKHEF (dec. 5th 2000) with high mechanical precision (16m 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….
Marcel Vreeswijk (NIKHEF) s
Expected shifts
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)
Marcel Vreeswijk (NIKHEF)
Gluing BOL-0• Guido laser test indicate tube
heights in combs <10um.
• Stability Xplates during gluing
Start glue
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
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 down
up up
Cross-plate sag. For chamber up (down) positions, a negative (positive) sag points down.
s
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
Marcel Vreeswijk (NIKHEF)
BOL-0Heat Studies (No flexoos in BOL-0)
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Inplane
Yrasnik= 2 x sag
The BOL-0 was covered with heat blankets, producing 50W/m2
Gradient between MLs: 2.5 to 4 oCSag of Chamber: 200um 50 to 80 um/oC= acceptableSag of xplate: 25um 6 to 10 um/oC = acceptable
400um
Yrasnik= 2 x sag
Xplate
50um
Chamber sag
Xplate
sag
Marcel Vreeswijk (NIKHEF)
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?)
tube
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