|
|
Michigan B184 Update May 28, 2004 |
Back to B184 updates * Previous * Next
1) Chambers passing CR test. Total: 22
Chambers passing CR test this week: EML3A07, EML4A05, EMS4C02, EMS5C08
2) Chambers in progress
EML3C05: will be ready for CR test (mezz scan) this afternoon
EMS4A12: One multilayer had zero pressure when crate was opened. The
leak was from the old ET. This multilayer needs to be
recertified. ET installed, cabling done, T sensors and inplane
system tested.
EMS5A10: ET installed, leaks found due to brass chip crossing signal
cap O-ring. needs to be recertified.
EML3C15: ET installed and is performing pressure recycling.
3) Chambers in hospital: none
4) Problems and other issues.
- CR test. Starting from the 21st chamber (EMS4C02) we set the mezz
card threshold to -40 mV. The hitmap showed many hot channels
before removing the noise. However, once the noise is removed,
hitmap/TDC/width distribution look fine.
Claudio has been working very hard to optimize the test procedure,
from different settings to automate the CR data analysis codes.
- The most time consuming work is still chamber gas leak
re-certification. because the old HEIM brass tubelets material
problem, we have to be extremely cautious with any chamber that
failed long term tightness test. For any chamber which has long term
leak rate great than 1 mbar, we MUST pay attention to it.
- For almost every chamber, we find 1-2 tubes with high dark current
(~100nA at 3.4 kV). We need to pin down the high dark current to the
tube, treat them with -HV.
ATLAS dark current specification is too loose. We should not use it
for our test.
- We found dents on 6 tubes of EML3C15 chamber. They were all marked
before.
- A NEW dent was found on one tube of EMS4C10 yesterday.
- Bldg 184 is becoming very crowded. To "calculate" precisely the
transportation of the chambers is a challenge to us. We now keep 6
stations and UW team has set up 3 stations.
- UW team has everything on their shipment. They almost rely on us to
start their work. I'm calling for UM people at CERN to try our best
to help them, under the assumption that our work won't be affected
much. We would like to emphasize the following that we have
discussed about at yesterday's meeting with UM team in bldg184:
(a) Remind each other the rules we have, SAFETY( personal and
chamber), quality and the last is quantity.
(b) Any parts, tools borrowed by UW should be registered so that we
have a record. Ask them to return the tools to the location when
they pick it up.
(c) Before one disconnecting any power cord or gas line, one MUST
first ask and check whether it is being used by others.
(d) When you move anything around or pass a chamber, be cautious not
to hit the chamber. It is not allowed to put any tools directly
on the tubes, or on an unstable place where your tool may easily
fall down onto a tube.
CERN is going to close next Monday.
Zhengguo Zhao