Chamber construction

• Construction Tools

• Production sites

• Assembly Sequence (“travelers”)

• Manpower

P. Campana LNF – LHCb Muon EDR Cern April 16th, 2003

Construction tools

Several steps in the chamber construction have been automatedto speed up production, reduce the needed manpower and increase precision and reliability of the MPWC. Tools are used to

• glue the frames to the panel• wire the panels• solder the wires• control the wire pitch • control the wire tension• assembly the layers• close the chambers

Each production site will have a set of tools.

Among the various sites, tooling has small differences (mainly due to characteristics of the different regions) :

• anode readout (R4)• cathode readout (R3 and inner M4-M5)• anode-cathode high density readout (inner M2-M3)

These “theme variations” do not change the main conceptual design of the chambers that remains uniform in the whole detector

These differences in the tools explain the small variations in the procedures for chamber assembly in the various sites

Some of these procedures have still to be validated with the experience we will accumulate in the first months of the production

Glueing the frames to the panel

Technique : perform a precise glueing of the frames (HV bars, lateral and side bars) onto the panels at the quote of 2.5 mm (to set the anode plane at the right level) with +- 50 micron precision

PANEL

GLUEING TOOL

HV BAR

GLUE

2.5 mm

2 panels can be glued per day on one glueing frameThis procedure is the same in all sites

Status : 1 table ready for PNPI1 (4 needed), 1 table ready for CERN (1 needed)1 table under construction in Potenza/Ferrara and 1 (simplified version)

in Florence (6 needed in the INFN sites)

CERN/PNPI

Glueing table with vacuum system for the frame and the panel positioning

The material is glued with structural epoxy and left under vacuum for several hours

Very good precision achieved

Wiring methods

COMBS

CERN (2 pairs)PNPI (6 pairs needed !)

INFN(3 pairs)

1 panel = 2 anode planes

1 panel = 1 anode plane

WIRE

WIRE

The different wiring methods do not affect the layout of the chambers

The time needed for the cure of the glue is a limiting aspect of chambers production (for PNPI site in particular, a large number of combs is needed)

Winding is performed at a speed of 6 -10 turns/min

The largest chamber is wired in about 2 h (positioning included)

Status :CERN, PNPI and Ferrara, readyLNF under setup (control of the uniformity of the wire tension)

Wiring Machines

Automated soldering (laser)

Status :

LNF (2 laser heads + cameras for wire pitch control) ready; mechanical settings to be adapted to the final chamber dimensions

Ferrara (2 laser heads + cameras for wire pitch control, integrated in the wiring machine) under setup

CERN, PNPI (iron head) device under procurement and setup

Ferrara

Ferrara

Laser 25 W 805 nm working at 60% nominal power

Soldering pads adapted for a continous solderingand for eye-guiding wire positioning

Tin-plates traces shows better results (truealso for iron soldering) at lower power

Low flux, low T, soldering wire (same of CSC-CMS)

Solder velocity : 5 cm/min (largest chamber done in 30 min with two-heads setup)

Two small cameras control the process

Afterwards, visual, detailed control of the soldering quality

Production sites (clean rooms)

CERN, PNPI, LNFready;Ferrara, Florenceunder setup

Travelers : material preparation & construction procedures

1) Preparation, cleaning and controls of panels and of side material (HV, side and closing bars; wire, etc...)

>> check of wire quality : visual inspection + stress test?>> dimensional controls

2) Glueing of bars on panels

>> dimensional controls

3) Wiring, glueing of wires

4) Wire soldering

5) QC on wire pitch and tension

6) Cutting wires’ end, cleaning of anode panels (for R4, mounting of R and C on anode bars)

7) HV test of single anode panels

8) Preliminary assembly of WPC, test with HV and dry gas

>> the 4 anode layers are assembled without glue for dimensional control and undergo preliminary tests with HV in dry gas environment

9) Final glueing/closing

>> two lines pursued:• in the high density region (all the boundary is filled with HV

connections and FEE pins), the baseline is the use of O-ring

• the rest would be closed permanently with glue

( this decision has to be validated also with the yield in the chamber construction)

10) Gas leak test

>> in case of closing with glue, a supplemental peripheral glueing has to be applied

11) HV training with final gas mixture

12) Chamber uniformity control

13) Final assembly of Faraday cage and FEE - Cosmic Ray test

>> this step is largely linked to the availability of the final electronics (only in July 2004). One part of the production will be equipped only afterwards. Tests on full preproduction and after on a small sample of chambers will be done with ASDQ

Manpower needed

Evaluation from “Travellers”

Site Chambers/week

Manpower(fte)

Notes

Ferrara 2.5 5 Panels glued in Potenza, chamber assembled and tested in Rome2

PNPI 1 5 14

CERN 1 2

LNF 2.5 6 +1 person from Rome1 for chamber assembly

Status of tooling as of end of march 03

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CERN

PNPI1

FE *

LNF * * * * *

ready * = under preparation in Potenzawell advanced ** = under preparation in Florenceunder preparation *** = under preparation in Rome 1to be built

Conclusions (open points)

• Final choice of glue

• Validation and commissioning of tooling

• Validation of closing methods

• HV training procedures