Michigan B184 Report February 19, 2004


1) Alan, Reza, Li have been trained and are able to work
independently. After working on another one or two chambers, they will
become experts on the chamber integration, I believe.
 
Alan and Reza work together for one station. Li and Helmut (now plus
Bingyun for training) for another station. Station leaders are: Alan
and Li.  Helmut has responsibility of doing many other things overall.
 
2) Two chambers (EML3C01, EMS5C16) have been CR tested. One is sitting
on the platform of bldg 184, and the other will be in the same
location next Monday. We will use the platform as a buffer for storing
CR tested chambers. Then they will be moved to bldg180.
 
CR test shows three hot channels in EML4A15. Two are not so hot and
one is very hot. We are cooking this chamber with HV=3080V and will
take data over weekend. We are trying to cook chambers with HV as long
as we can. It seems three days is possible.
 
Both two stations are working on another two chambers (one EML3, one
EMS5), gluing T sensors, survey targets, B sensor platform and
cabling the chambers.
 
3) Two DAQ systems for CR test are working in expert mode. Next week
Jeff will shift them to operator mode so that we can operate the
system alone.
 
All PCs in bld184 are working, and be able to access network. Thanks
to Shawn and Jeff. Wireless is also working fine.
 
Problems and questions: 
 
1) Cracks on endplug of EMLS5A08 (the second michigan chanber) were found.
 
EMS5A08 is one of the two EMS5 chambers which failed long term leak
tightness test (They have been certified at ISR in 2002). This is also
why we intentionally deal with these two first. leaks were found from
old type ETs last year when I measure the pressure of the chambers.
This time we tried hard to recertify EMS5A08. In the end, we found
leaks at fixed location between half jumper and endplug at the rate of
10^-2 or 10^-3 cc/s. Then using magnifier one can see cracks on the
edge of the endplug. We first found three, then another two.
 
The first one can be easily seen by eye. I inserted a plastic red cap
which we used to locate the leak onto the signal pine, then a piece of
endplug with a dimension of about 10x2 mm^2 dropped down. Indicating
that the crack is very fragle.
 
Since we have already 5 tubes with cracks, we decided to apply epoxy
to cover the endplug and half jumper emtirely.  We will see what will
happen then.
 
According to Bing, the early endplugs seemed have quality problem.
 
The questions are:
 
1) How many endplugs will be found with cracks? Are we going to suffer
finding more developed in the future?
 
2) Can we use epoxy to cure the cracks? do we risk losing the whole
multilayer by curing the cracks?
 
In the beginning we found one endplug with crack, I intended to simply
kill it in order to risk lossing the emtire multilayer in the
future. But now we find 5, and it may worth trying of curing them with
epoxy.
 
Both Bing and I are thinking whether we should apply epoxy to endplugs
for the entire chamber. It cost about 1.5-2 days for two persons. We
will have to make decision some time next week when we know the leak
rate of the five endplug cured with epoxy by Helmut.
 
3) So far the DAQ systems for CR test are unable to tell the
information about threshold, efficiency..... Therefore they are not
crossed on check list.
 
4) The measurement of the survey target/B platform positions are not
done so far. We need feeler gauge to do so.
 
5) DAQ system for testing inplane system needs to be worked out. I
believe Ed is making effort.
 
We keep a hard copy of the traveler for each chamber. I suggest that
we add the hitmaps of each sublayer and TDC spectrum of each mezz card
as well as tracks from top layer to bottom layer (top mezz card to
bottom mezz card) to the webpage.

Zhengguo Zhao
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