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Michigan B184 Update May 7, 2004 |
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1) Chambers passing CR test
a) Chamber passed CR test this week: EML3A15, EMS4C16
b) Total number of chamber which have passed CR test at CERN: 18
2) Chambers in progress
EML3A07: Taking CR data
EML4A05: Taking CR data
EMS5C08: Ready for CR test
EMS5C02: Glued survey target and B sensor platform. T sensor and
inplane system tested.
EMS4C10: Glued survey target and B sensor platform. cabling
done. start pressure cycling.
3) Chambers in hospital: none
4) Claudio's report on noise in CR tests:
Good news from B184: the noisy chamber (EML3A15) we took long time
to investigate is today very quiet. For who's interested to see
everything we stored about this chamber, the place is
atums1.cern.ch:/home/muonuser/chamber/data/eml3a15, with a README
file explaining in short the different run conditions). Of course
it didn't depend on the chamber (we didn't flush more gas than
before, not mezz cards replaced, ...), but likely the changes on the
setup helped a lot:
1) Same ground for Scintillator HV PS and TTC (plus computers and LV PS),
while NIM crate and Chamber HV PS on a different ground.
2) A splitter box with filter (as used in H8) for the trigger scintillator.
3) Shorter (and new) HV cables
4) PS far away from the chamber as much as possible
Since this chamber is the space Washington will use, we are packing
it. I suspect the different splitter box for the scintillator, and
maybe a little bit the cables, is/are the real responsible of the
improvement, since the runs with different combination of HV
on/off/disconnected and ground schemes
(atums1.cern.ch:/home/muonuser/chamber/data/noisetest/) do not show
any difference between them. I plan today on the next (hopefully
good) chamber to see which one of these factors had a major role on
killing the noise.
5) Other issues,
Noise problem almost solved. As claudio reported, this morning we
have a quiet chamber past CR test. More step-by-step study is
needed to find out what is/are the noise source(s).
Integration work goes fast now. we are quite confident that we could
work out two chambers per week, amy be even more, if nothing
unexpected is going to happen. of course, this is assume that cr
test could catch the speed.
CERN is going to close from tomorrow to next monday. I wish you all
have a wonderful holiday and safely return to work at CERN next
Tuesday.
Zhengguo Zhao