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Michigan B184 Update December 3, 2004 |
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UM chambers: We are dealing with the two dropped chambers this week. In principle we need to re-certify the chambers. EML4A07 - leak rate for both ML are around 0.4 mbar/day for Ar+CO2 at 3 bars (for over 60 hours). - dark current has no problem at 3.4 kV - electronics test is fine - CR data is fine (tdc spectra and charge width) EML4C07 - leak rate: still certify, so far looks at the level of 1-2 mar/day - dark current is fine Planned crane operation this afternoon was canceled since the crane team has to deal with trucks for CMS. Next week we will put EML4C07 back to box and perform CR test, and EML4A07 will be mounted to the transportation card. The damaged (shape distorted) box for EML4A07 will be repaired by CERN, maybe some time next week. ========================================================================= UW chambers 1. Passed CR test: EMS2A04, EMS2A12 2. Chambers in progress EMS3a08: check leaks Chamber to be reworked for UW EML2C09: Dealing with hot tubes for almost one week. EMS3A06: Dealing with hot tubes for almost one week. EMS3C16: Taking CR data EML1C07: Soon be ready for CR test =================================================================== 1. Problems and other issues a) UW chambers that have done CR test at UW appeared to be very difficult to work for due to noisy tubes, either hot tube or the epoxy applied. so it is expected that their 44 chambers that need to be reworked will take about 3 months if all chambers behavior like the two we are working with. b) This afternoon there was a demonstration on how to lift chambers in bldg180. Curtis, Matt and I were there (Bing was at another meeting). Matt has taken some pictures. My personal feeling is that if this is still not safe, hardly we can do anything then. Curtis will report the detail, I guess. Zhengguo Zhao