the making of the bol-0 @nikhef

Marcel Vreeswijk (NIKHEF)

• Assembly Station• Sag adjustment• Gluing BOL-0• Temperature studies• Summary

The Making of the BOL-0BOL-0 @NIKHEFThe Making of the

BOL-0BOL-0 @NIKHEFNIKHEF ATLAS MUON group: H. vdGraaf, F.Linde, G. Massaro, M. Vreeswijk, P. Werneke


Assembly Station

West side has expansion length o 0.1m in Xras

• Granite table: 6m x 2.5m

•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)

Situation mid 99

North X

East Z

Up Y

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Precision Mechanics


• 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

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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)


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)

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Spacer


• 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


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).

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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

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Sag Compensation• Sag compensation has been used manually.

• Three pressures: 2 x outer (practically equal) and inner Xplates.

Model Pressure (bar)longbeams crane sagbar XP total Predict from weight Observed

Outer + 32 17 10 10 69 3.5 3.0 - 3.4Outer - 0 17 10 10 37 1.9 1.2 - 1.4Inner + 0 0 20 10 30 0.8 0.4 - 0.5Inner - 64 0 20 10 94 2.4 2.2 - 2.3

weigth (kg)

After consistent results we adjusted the sag to obtain (almost) symmetric weight distribution

Sagcompen-sation tower

Additionalweight forsafety

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Sag Compensation• Xplate sag before adjustment

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Chamber (upside) down

Chamber up

Asymmetric sag Xplates, due to asymmetric weight distribution during gluing spacer -> Adjust


Sag Adjustment• Xplate sag after adjustment

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After sag adjustment we observe (almost) symmetric sags for chamber up and down positions

Chamber up

Chamber (upside) down


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

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QC-Wire position

Quality Control on drift tubes, specs:•Wire position: |Y,Z|<25um

Rejection 2%

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1 tube was found with R>100um. A destructive check revealed: no twister in endplug


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

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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

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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 )

Rejection 4%

10-1

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• Quality Control on drift tubes, specs

QC HV Check

•HV 3000V , current <20nA

Rejection 4%

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Current versus HV

0

20

40

60

80

100

2000 2500 3000 3500

HV (V)

Tube

cur

rent

(nA)

Current versus HV

Current versus time

0

10

20

30

40

50

9:00 11:24 13:48 16:12 18:36

Time (h)

Tube

curre

nt (n

A)

Current versus time

Accumulated excess current Tubes

0

5

10

15

20

25

0 200 400 600

Total # tested tubes

To

tal

# o

verc

urr

en

t tu

bes

AccumulatedOvercurrent Tubes


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)

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Gluing BOL-0Problems:•Nozzle mounting very critical•Central glue ropes between tubes not uniform/symmetric

•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)

Solutions:•Reduce Glue machine X speed by two (now ~10m/s)

Bigger central glue cilinder

Glue stop for tape

tube

glue

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tube


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

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Gluing BOL-0• RASAS monitors

SE

NW

SW

NE

Global Z,RASAS X

Global X

Global Y (up)

•Stability in Y appears very good ( for some layers the RASAS indicated problems which could be online corrected)

Global Z

•Relatively large Z movement layer 6 (spacer floats on glue?)

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Lever arm in stacking block


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.

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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..

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BOL-0Heat Studies (No flexoos in BOL-0)

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Yrasnik= 2 x sag

XplateInplane

Yrasnik= 2 x sag

The BOL-0 was covered with heat blankets, producing 50W/m2

Gradient between MLs: ~4 oCGradient over Xplates: <0.3 oC (would be larger with flexoos)Gradient over tube layers: ~0 oC

Sag of Chamber: 200um /4oC= 50um/oC= acceptableSag of xplate: 25um / 4oC = 6um/oC = acceptable


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.

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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)


Assembly Station



Gluing BOL-0

Layer 1

Layer 2


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.


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).

In mrad

um


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


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.


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


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.

0 1 2 3W E

A+ Y -28 -45 -50 -26A- Y 102 195 200 94

E WC+ Y -18 -55 -50 -41C- Y 82 205 200 114

0 1 2 3W E

A+ Y -41 -42 -48 -25A- Y 111 192 198 95

E WC+ Y -25 -48 -42 -41C- Y 95 198 192 111

Data of the four in-plane systems:

Although steps appear large and uncontrolled, the data is reasonably well described by the model (10 um)

Model

Data


In-Plane RASNIKs


• Model Parameters

Implications:

1) Sag of Xplates as function of additional weigth consistent with data.

Model Datasag@LO sag@LO

outer XP + 57 53outer XP - 37 35inner XP + 36 40inner XP - 76 83

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 alsoqualitatively by optical alignment tool!!!!!

3) In A+ position, when the spacer was glued, longbeam weight on outer Xplates!!!!

slope 1 XP sag um/kgWoff 36 XP Sag for 32 kgMW 32 Middle Sphere tower alignment (um)ME 25 Middle Sphere tower alignment (um)Was 16 Weigth difference on outer XP in +/-

Uncertainties 10%


Sag Compensation


Sag Compensation

0.4 bar


Sag Compensation• Shape without sag compensation


Sag Compensation• Shape with sag compensation


The road to BOL-0Date Item Comment1999 Cleanroom Prepare assembly stationApril 2000 Spacer Construct spacer

Nov. 2000 Setup ready Glue machine studies15/11 1st layer Gluing central ropes16/11 Platforms Problems with intrinsic

accuracy20/11 Spacer Spacer on 1st tube layer21/11 2nd layer Gluing central ropes22/11 Spacer Spacer+1st+2nd layer23/11 3rd layer First layer to layer;

problems with glumachine

24 –28/11 Glu machine Change CentralCilinders

29/11 4th layer Ok

1/12 5th layer Ok5/12 6th layer 20um Z shift

BOL0S M N S M N

L1 2.1 1.3 2.2 2.1 1.3 2L2 2.6 1.75 2.9 2.7 1.75 2.8L3 2.8 1.9 3.3 2.7 1.9 3.1L4 3.5 2.2 3.7 3.4 2.2 3.5L5 4.2 2.6 4.1 4.1 2.6 3.7L6 4.7 3.4 4.6 4.6 3.4 4.2

FLES BINNEN


The road to BOL-0BOL0bar S M N S M NL1 2.1 1.3 2.2 2.1 1.3 2L2 2.6 1.75 2.9 2.7 1.75 2.8L3 2.8 1.9 3.3 2.7 1.9 3.1L4 3.5 2.2 3.7 3.4 2.2 3.5L5 4.2 2.6 4.1 4.1 2.6 3.7L6 4.7 3.4 4.6 4.6 3.4 4.2

BOL0kg S M N S M NL1 26 16 25 53 65 50L2 34 22 35 68 88 70L3 34 24 39 68 95 78L4 43 28 44 85 110 88L5 51 33 46 103 130 93L6 58 43 53 115 170 105

BOL0kg S M N S M NL1 27 16 27 53 62 53L2 33 20 33 65 81 65L3 39 25 39 78 100 78L4 45 30 45 90 119 90L5 51 35 51 103 138 103L6 57 39 57 115 157 115

PRED./TOWER PRED./XP

BOTTLE GAUGE

FORCE/TOWER FORCE/XP


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

QC Rejection Tool

Wire position 2% ‘Pick-up coil’

Tension 350gr 275gr

5%3%

CAEN-frequency

Leak rate 4% Coffin

HV 4% nAmp meter

By mistake


Gluing BOL-0• Layer 3


In-Plane RASNIKs


• The calibration of the In-Plane (Y) is extracted from data in A+, A-, C+, C- positions..


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


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’

the making of the bol-0 @nikhef

Documents

sag compensation xplate

expansion length o

sag of granite table

um west

sphere holdersthe combs

sphere towers

multilayersassembly

um level