Production Readiness Review of

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Production Readiness Review of Frascati MWPC
Production Site
December 4th, 2003 P. Campana
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• Scope and Goals of the PRR
• Verify / assess
• Readiness of the chamber design and of the
  construction procedures
• Readiness of the tooling and of the production
  site
• Quality controls and assurance tests
• Material procurement and its flow
• Interface and integration issues
• Chamber logistics
• Manpower availability
• Production and installation schedule

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• Status of LNF production site
• In August, the set up of the clean room (transfer
  and set up of tooling)
• In September-November startup of M3R3
  (pre)production 4 final chambers done (two more
  under construction)
• 2 chambers tested under beam
• choice between double and single cathode readout
• test ASDQ vs Carioca
• Several upgrades of the tooling done and to be
  done (automatic gluing, more HV bar gluing
  tables, etc...)
• A lot of effort in finalizing QA/QC tests and in
  optimizing the work flow (this has still to
  improve)
• The production speed was limited by material
  availability and to several operations we plan to
  do in outside company (e.g. components on HV bars)

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• EDR recommendations
• A small pre-production series should be
  constructed and tested for each chamber type
• The goal was to build and test 4 final chambers
  we succeeded in building them, but due to time
  shortage, and many other commitments (and a
  small accident), only 2 were (nearly) fully
  tested
• 2. At least one of these pre-production chambers
  of each type should have undergone a successful
  ageing test
• This has been done with LNF prototypes in
  Casaccia. This item has been discussed at length
  in CERN PRR and will be not treated here
• 3. The opening of the chambers should be
  exercised. In fact, the reviewers are mostly
  worried about the proposal to close two of the
  three chamber types by gluing
• This will be discussed later

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• A wire replacement procedure should be defined
  and tested for each chamber type.
• This happened several times and will be
  explained in the afternoon
• 5. At nominal gas flow rate, the eventual
  formation of pockets should be checked by
  efficiency mapping, especially in the case of the
  longest chamber type.
• We did uniformity checks and no particular
  problems appeared
• 6. As the gap size is probably the most critical
  parameter for pulse height uniformity, an effort
  should be made to produce panels of best possible
  flatness.
• This will be reported later
• 7. The sagitta of the panels due to wire tension
  should be measured, for those panels carrying
  wires only on one side.
• Calculations and direct measurements show no
  sizeable effect

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• The precision of the wiring should be checked on
  all pre-production chambers.
• This has been done for the pre-production
• 9. Gluing should be handled with the utmost
  attention, with well tested, constant procedures,
  in particular under lt50 humidity
• Does not represent a problem and its
  automatisation is under way
• 10. Chamber materials and components (panels,
  bars, wires, glue, resistors and capacities)
  should be identical as much as possible for all
  chamber types.
• Largely achieved (already discussed at CERN PRR)
• 11. A well-defined testing procedure during
  production should be established with the
  pre-series, including some final two weeks of
  operation at nominal voltage with final gas
  mixture and flow.
• Fully done for 2 chambers, under way for the
  remaining 2
• 12. On the basis of the experience gained with
  the pre-production series, the production
  schedule should be re-evaluated
• This item will be discussed later

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Chamber gluing and its reliability In the period
2001-2003, 11 MWPC chambers were built in
Frascati of various dimensions (1.5/2.0 mm pitch,
6 of final size) and all the chambers have been
glued and built with similar techniques None of
the 960 wire pads of 9 chambers (some 15,000
wires), tested under HV showed problems so
important to need a reopening of the chamber In
these chambers we observed that after few weeks
of constant gas flowing also the wire pads that
initially were more sensitive to HV, recovered
and could be operated at the same HV as the
others In the overall design we considered of
utmost importance the availability of the access
to single pads we believe this is mandatory for
a detailed tracking of problems (especially
before chamber closing) and even afterwards, in
case a single pad shows some HV-weakness, it can
be re-routed on a lower-HV line (the so called
hospital channel, which we foresee in our
layout), without spoiling the overall chamber
efficiency and without the need of reopening (or
worst) throwing away a full chamber
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A stressing HV test should not be performed in
the presence of humid gas, such as open air
during their construction in the clean room We
experienced that only after a very long (several
weeks) training with increasing steps in HV and
maintaining always a low current limit (in the
range of 300-400 nA for a gap of a big chamber),
the chamber can reach operating voltage well
beyond its working point The first two final
M3R3 chambers (C001-C002) were kept for 3 weeks
at 2.75 kV (200 V inside efficiency plateau) with
currents of few nA/gap We observed that a
resonably fast and simple HV test (few hours,
current limited to 200 nA per wire layer) during
the production in the clean room is able to spot
problems (see Carlos talk) On the experience
gained in two years of MWPC construction, we
believe that, once reasonable HV QC tests have
been performed, the chambers can be safely closed
with a definitive gluing
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Status of panel production It is going on (300
for PNPI 100 for INFN) at a rate of 25-30/week
for a single mould (yesterday, 130 done, 6
discarded) See Carlos talk for details on
planarity measurements Rome 2 is setting up the
automatic measuring device at the company New
moulds (M2-3, M4-5) under construction (one
ready by Christmas) The final set up (with 3
moulds) foresees 20 panels/day (total no. of
panels 5360 gtgt 270 working days spare) A
detailed production plan for panels has to be
setup to ensure continuity for various production
centers We are planning also a clever scheme
for expedition of panels to CERN/PNPI to minimize
the number of transports and the number of boxes
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• Program outline
• Carlo Construction procedures, travellers and
  QC/QA
• Davide Source and cosmic ray test stands
• Gaia Test beam on M3R3 chambers
• gtgtgt break
• Alessio Access to chamber construction
  information
• Adalberto - Interface and integration issues
• Pierluigi Material procurement, logistics,
  manpower, production schedule
• gtgtgt lunch
• Visit to production site