Michigan B184 Update March 12, 2004


1) EML4A15 chamber had one very hot channel, two relatively hot
channels when bing was here last week. It spent us one week to deal
with these hot channels, and then spikes relating to 12.5-25 ns
clocking. In the end, we applied -hv to this hot tube.  Jeff is
reporting the detail about how to reduce the spikes.
 
Finally we crated this chamber yesterday afternoon and moved this
chamber to B184 platform this morning.
 
2) For chamber EMS5A08, we struggled one week, trying to certify it,
and now we found cracks on 10 endplugs in total.  It has gone many
times presurizing/depressurizing. here are the tubes having cracking
endplugs(use the DB definition):
 
ML1-1-16,57; ML1-2-17; ML1-3-16,21  all at OR end       
(57 is not listed in the table)

ML1-3-50      at HV end       
 
ML2-1-8,14    both ends  (8, 14 are not listed in the table)
 
Of which 5 belong to the table (listing about 200 endplugs used to
this chamber) I got from Helmut and 5 not.  We succeeded in curing the
leak with epoxy for 4 endplugs, and failed one due to it's location
around the corner. (it has been done twice).  For this chamber, I
suggest that we simply apply expoxy to all tubes. We will start doing
so this afternoon.
 
3) EML3C03, we spent one day to trace the three tubes having high dark
current. and treated with -HV=2500 V. there has been a mysterious HV
trip: dark current is about 80-180 na/60 tubes, which is very
low. then it tripped sometimes.  this morning we use indpendent HV
channels for the multilayer, no trip yet (maybe the source of trip
disappered due to HV cooking).  We can always find the reason and solve
it. It's a question of time and effort made.  We now have 6 stations
to work with. we are working in parallel with 5 chambers so far.  I'm
very happy to see that we have a confortable working atmosphere to
work together. people are coperating, helping and remind each other,
though they have their own stations and responsibilities. These three
words are our principle: safety, quality and quantity.

Zhenngguo Zhao
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