Michigan B184 Update July 9, 2004

1) Chambers passing CR test
 
  a) Chambers passing CR test this week:  EML4C03, EMS5C04
  b) Total number of chambers passing CR test at CERN:   35
 
2) Chambers in progress 
 
  EML3A09: CR data analysis.   
  EMS4A02: taking CR data. 
  EML4C13: waiting for CR test
  EMS4A14: installing mezz card
  EML3C11: testing dark current
 
3) Chambers in hospital. 
 
  EMS5C14: Epoxy was applied to the location between AL ring and noryl
  for all tubes.  The chamber cured for 3 days and was then
  pressurized with Helium to 3 bars.  The leak rate is about 7mbar/day
  for helium at 3 bars.  This time epoxy does not improve the leak
  rate.  Q196 didn't find any leaks.  We are waiting for the Vecco to
  scan the leaks once more, and then make decision what to do with it.
 
  The Vecco has arrived at CERN, but not yet to bldg184, according to
  Ed, who keeps tracking on it with the help of Atlas secretary.
  
4) Problems and other issues
 
  a) Mezz card rejection.  We have twice mezz card pre-selection,
  based on mezz card ID and the DB.  We probably need to do more round
  of preselection.
 
 The criteria to reject mezz card (HV off and on)from the mezz card
 scan done by us is still not clear to me. If we stick on the criteria
 Tieshen gave me (e.g. resolution<3 unit, correlation efficiency > 80
 ...) we found many more needs to be rejected.
 
  Since mezz scan already gives warning messages. I suggest that in
  the summary file from the mezz scan to add message indicating which
  mezz card needs to be rejected due to what reason. Then operators
  can easily see which card needs to be replaced for what reason. If
  we don't follow the criteria we have, what do we test.  If we
  strictly follow the criteria, we need to replace many more mezz
  card, it seems to me. e.g. each chamber I have seen a few mezz cards
  that have resolution > 3 units (0.78ns/unit).
 
  We need to discuss this issue more in detail, and measure needs to
  be taken to make the criteria clear.
 
b) Mysterious chamber HV trips
 
   Many times we find that HV trips during the night.  Now we found
   bugs (insects) are the ones to be blamed, at least we found 2 trips
   due to bugs.  We probably need to find a bug trap to install in
   bldg184.  Anyone know where and what kind of bug trap we should
   use?
 
c) Chamber transportation
 
  We request crane operators to come every morning, and we have good
  relations with them.  So far there have been no problems handling
  chambers with the crane.  But chamber transport has become
  difficult, at least much slower than before, even though we request
  the transportation one week in advance.  I will discuss this Joerg
  after his vacation.
 
Zhengguo Zhao
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