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Status of production at LNF

Detailed update on production status at LNF, focusing on chamber differential and integral closing rates, reasons for delays, wire tension, HV-bar issues, panel winding rates, and upcoming production schedules.

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Status of production at LNF

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  1. Status of production at LNF Monday 24-may: closed chamber 30. Will close 2 more this week. E. Dane, C. Forti, D. Pinci, A. Sarti – LHCb Muon CERN 25-may-04

  2. Chamber differential closing rate

  3. Chamber integral closing rate

  4. Panel differential winding rate

  5. Panel differential winding rate

  6. Panel average winding rate

  7. Reasons of delay For some time the company producing the cathodes did not send the FR4 foils with cathode pads to the Internormal. In 2 periods: 7-16 Apr. and 27 Apr.  5-May we winded only ground panels (layers L1 and L3) and could not close chambers. HV-bars drawing current: from 15-Apr we found panels drawing current during the HV test. The possible cause was a set of HV-bars with much humidity in their plastic bag. They were cured by heating (under infrared lights) and, if needed, removing the conformal coating and cleaning them. Then we started a systematic check of all HV-bars. We found a panel with tested HV-bars drawing current: we investigated the wire under the microscope but did not find a systematic difference between samples from good vs. bad panels.

  8. Observation of wire from one panel drawing current We found a panel with tested HV-bars drawing current: we investigated the wire under the microscope but did not understand much. gold removed

  9. Observation of last 6 spools received All samples seem OK

  10. Wire tension In panels with smaller <T> : wires have been glued at smaller tempe- rature and/or wires have been cut too soon ( after ~12 hrs) We reached the goal s < 2 g We have increased the power of heating lights and fresh gas was put in the clean room conditioning system

  11. Fraction of substituted wires 113 panels of chambers 6-35 < 1 per mil

  12. HV test 100 panels of chambers 6-30

  13. B higher Uniformity test: currents in gaps and bi-gaps C>>D The uniformity between different gaps of a same chamber and of different chambers is improving compared to cham 1-10 CD OK In chamber 22, gap B draws ~ 50% more current 320 vs. 220 nA

  14. Currents in chamber 24

  15. Currents in chamber 22

  16. C Effect of brass bars ch 22 (C,D) Chamber 22 gaps C,D The 3 brass bars put below the chamber as support, produce a visible effect on gap currents D

  17. >95% in range (0.8 – 1.25) G0 14 chambers rejected less than 4 gaps OK N. of goodgaps in each chamber (1-25) >90% in range (0.8 – 1.25) G0 8 chambers rejected less than 4 gaps OK

  18. >95% in range (0.8 – 1.25) G0 4 chambers rejected: 1,2,4,5 less than 2 bigaps OK N. of goodbi-gaps in each chamber (1-25) >90% in range (0.8 – 1.25) G0 2 chambers rejected: 4 and 5 less than 2 bigaps OK

  19. End of M3R3 production (52+2 chambers) End M3R3: 30-jul / 16-aug Start M5R3 in September

  20. End of M3R3 production (216 wired panels=54 chambers) End M3R3 calculated from winding rate: 30-jul / 21-aug

  21. LNF production schedule (updated 24-may-04, ch. 30) (52+2) M3R3 + 52 M5R3 + 52 M1R4 + 125 M1R3 = 283 Holidays: 2 weeks (Christmas) + 1w Easter + 4w August = 7w End prod. = Plan: 15-mar-06 Extrapolation: 26-jun-06

  22. Conclusions • Wire tension: • reached the goal s < 2 g • 2. <T> smaller in 4 panels  temperature in winding machine increased. • Wire pitch: never found a wire out of specs (<1.9 or >2.1 mm) • Other procedures are stable and OK: wire soldering machine, panel • preparation, WTM, HV test, chamber assembly. • We are investigating the cause of some panels drawing current even if • HV-bars. May be the wire is dirty ? It gets dirty during soldering procedure ? Chambers produced up to now: one chamber (N.3) leaks. Uniformity test: 4 chambers (1,2,4,5) with bi-gaps area < 95% in range (0.8 – 1.25) G0  we will build 2-4 more M3R3 chambers. Cosmic ray stand, nearly ready, will allow soon to switch on 6 chambers together for a ~2 weeks conditioning

  23. HV test 100 panels of chambers 6-30

  24. HV and ground connections check Altough the beam flux has a 15 cm diameter, the system can give very precise information A 2.75 cm pad disconnected from ground A wire pad (13 wires x 2 mm pitch) disconnected from HV

  25. Gap C Gap D Chamber 12 A bent panel between gaps C and D provides this situation: the gain in the gap C and D not uniform... What about efficiency, time resolution and cluster size? ... to be investigated with test beam or cosmic rays... ... while the gain of the Bi-Gap CD is rather flat. Bi-gap CD

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