LNF activities on WPC Panels Construction of prototypes and layout Status of tooling Proto 0, open items, plan,...

First long panel (M3R3) produced on last Thursday, measured on Friday. Quite satisfactory (within specs). No border effects, except in one point, where O-ring to avoid foam leakage was uncorrectly mounted. Some small improvements under way (better foam mixing). More panels under construction to test reliability of production. Meanwhile we proceed for construction of mould for stations M4, M5 (drawings ready) Mechanical characterization nearly completed in Potenza

Some more mechanics is needed to move easily the top cover of the mould and speed up operations, together with cooling system To study and to setup : production and quality controls procedures (at the company and at home) production time plan optimization of no. of moulds vs cost and production time: M3R3 (done), M5R2 (all R1 & R2 panels), all smaller panels obtained by cut ? Build also M2R3 ? About 5000 panels to be produced 2/hour = 70 weeks (to be verified)

Status of 3 protos All closed with glue, under HV training. In air up to 3.2 kV, 0 nA. Up to now, no problems. Soon after HV training, gain scan with source and equip with ASDQ. Bring to test beam in May. We are satisfied with geometry and construction procedures: HV bars at 2.5 mm level, 5 mm spacers, closing bars with protection for HV traces, cathode ground planes with no traces, gas bars with economic nipples for plastic pipes with independent I/O per each gap, no screws, only reference holes at the 4 corners

New type of glue (3M DP460) for chamber closing Araldite not good for structural gluing (does not attach on copper Fr4 plates). DP460 is tixthropic and can be handled for a while (few hours curing) : very strong attachement Two methods 1. “or-ing” of glue: a calibrated amount all around the frame 2. “peripheral”: glue on the outside part of the chamber, to seal against gas leaks Both methods fast and easy, although (2) seems better, but...

In a chamber glued on the periphery, we observed dark current (few nA) with wet atmospheric conditions, due to glue between outer traces and ground plane panel Wire bar glue May be this is due only to bad surface cleaning, but we want to investigate better this effect. No problems (no current) with the other gluing. Not yet fully tested the real gas leakage (not measurable with present setup: much less than 1 bubble/min) HV traces ground

Wire Tension Measurement Test done with 1 channel (KLOE /Atlas method) and “hand movement ”- 16 channels unit with serial interface under production Probe (100  m Al wire) WPC wires to ground Mechanical frame and automated movement needed

Status of other tooling / other activities (LNF) Tools for chamber assembly and gluing under definition: reference bars with ventouses, chariots, working tables, shelfs, etc... Wiring machine: we started to copy Fe & CERN ones Assembly clean area (delayed): civil works will start in May, ready in summer

Soldering machine : final cabling, ctrls and second head (to be used for proto 0) Drawings for all PNPI-INFN chambers (10 types) HV cards: 3 cards to fit all regions (prototypes ready to be tested) Mechanics of muon system: ready to mount the wall (half of M2)

Steps to INFN proto 0 M3R3 Pads, HV bars, closing bars, gas bars ordered (pads and HV bars in 3 pieces to be joined) Material for panels available ASDQ and SPB ordered and under arrival HV cards to be prepared Ferrara wiring machine adapted to M3R3 Plan to wire in Ferrara, bring to LNF, solder and close Work to be done in May-June, test in August Meanwhile, as M4M5 mould is ready, prepare above steps for proto M5R2

Open items : Wire choice (Toshiba vs Luma; Kloe had positive experience with Luma, 70 km, inspection tests) Gas flow and connections (as simple as possible!, plastics) Quality tests after closing : gas leakage, source test, CR (see Rome 1 contribution) 2002 and beyond production plan and material procurement

Cost update quotation on pads (in 3 pieces, one side, R3) around 100 FS/pad quotation on HV bars : 40 FS/m These prices can be lower for large production, and the company could produce long elements if needed gas bars (large #, Fr4, machined) : 6 FS/unit closing bars (large #, Fr4, machined) : 10 FS/m Prices in agreement with previous table costs

0.05 l/h 50cc/60min 1cc/min in 75 litri