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Michigan B184 Update September 10, 2004 |
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1) Chambers passing CR test
a) Chambers passing CR test this week: EML3A01, EML4A13, EMS4C04
b) Total number of chambers passing CR test at CERN: 58
2) Chambers in progress
EML5A03: CR data has been analyzed. The bottom multilayer has a
relatively long tail in TDC spectrum. We will flush more gas to
seen whether it improves. Otherwise the long tail may come from
the tube distortion.
EML4C15: First mezz card scanning failed due to low correlation
efficiency of the two cards. We are repeating the scan and then
will decide next step.
EMS5A14: Long term leak rate is about 2 mbar/day, high according to
our criteria. Short term leak rate is about 7mbar/day for helium
at 3 bars. We will use the Vecco to see whether there are leaks
from the Al ring and endplug location and then decide what to do.
Since we have problems with old HEIM tubelets and also endplugs,
we have to be more cautious with leak certification.
Notice that ATLAS specification changes to <10mbar/day for chamber
working gas.
3) Chambers in hospital.
EMS5C02: Epoxy has been applied to the location of Al ring and
endplug location for ML1 (bottom ML). This chamber also has high
dark current, about 3-5k nA/sublayer. The high current is more or
less evenly distributed on the tubes. We are now cleaning the
location between signal cap and endplug for all tubes.
4) Problems and other issues
a) We relocated our stations, shrinking from 6 to 5. We will reduce
by one more station so that we have more space for working on UW
chambers.
b) Operators are still unable to test DCS box. Some problems need to
be solved by Jeff. (Jeff has been informed and he will come to
solve the problem)
c) We installed the DAQ system for leak rate measurment. This system
is from the last shippment. however, no user name and password
attached. I'm wondering whether Dan still remembers them (gashead,
ArCO2937?).
Zhengguo Zhao