Michigan B184 Update June 18, 2004

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1) Chamber passing CR test
 
 a) Chamber passed CR test this week:  none 
 b) Total number of chamber passed CR test at CERN:   26
 
 2) chamber in progress 
 
   EMS4C06: Retaking CR data  
   EML3A13: CR data has been taken and analyzed, redo the mezz scan
            with HV off and on.
   EMS5C06: Ready for CR test 
   EML3A11: Ready for CR test
   EML3A05: T sensors and inplane system tested, dark current measured. 
 
 3) Chambers in hospital 
 
   EMS5A10: After epoxy cured for three days, we pressurized it with
        helium to 3 bar.  Vecco was used to scan the leaks. Leak rate
        was reduced by half.  Continue to debug the leaks.

 4) Problems and other issues  
 
   a) Tubes having high dark current

   EMS5C06 and EML3A13 have 12 and 4 tubes with high dark current
   respectively.  The dark current ranges from 100 na to over 1000
   na. All are being treated with -HV=3.2-3.4 kV.
 
   It's extremely time cosuming to deal with chambers with so many
   tubes having high dark current.
 
   b) Parts and tools
 
     - since we have preassembled all FC and motherboards, we are able
     to count our parts once more.  This time should be more precise.
     A list of parts UM requested has been sent to Bing.
 
     - We are running out of SHH boards.  A message has been sent to
     Robert.
 
     - We do find another box of B sensor platform.  
 
     - Since UW is sharing all our parts, parts inventory will be more
     difficult.  We have a notebook to register all they take.
 
     - A HV power supply was broken by UW. 
 
     - A Q196 is broken by UW. 
 
   c) There were twice the power cords were unplugged without
   notifying the users.  This cause lost our time for CR test.
 
   A sign is now put on the switch board please "don't disconnect the
   power cord "
 
   We now decide to the fix extension cord to each station. 
 
   This is week we fight toubles, leaks, high dark current, rejecting
   mezz cards, .....
 
   d) Reminders
 
     - Don't tune any devices before consulting experts.  The low
     voltage power supply on DAQ system for CR test is not allowed to
     be tuned.
 
     - Please inform me before you bring any tools and parts away from
     bldg 184.  This is just to avoid spending lots of time searching
     around.
 
     - As you can see, if we don't work out the chambers for CR
     test. We don't have much to do, so speeding up the CR test is
     crucial again.
 
Zhengguo Zhao

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