L14 has been tripping very frequently since yesterday afternoon. during
an access to the southhall, tripping between sense and guard wires in one
cell (the 17th least-downstream cell in the superlayer) in the box was
seen.
however, this cell in question is physically located pretty much
square-dab in the middle of the sector. as such, it's very hard to
discern which sense wire is to blame. as such, replacing the afflicted
sense wire could mean (if luck is not with us) replacing up to three sense
wires. as such, it is somewhat of a relatively large project (a couple of
hours, i'd guess, counting in the contortion involved with getting into
the right positions to restring a wire). since the hall is to be open all
day tomorrow, it has been decided that we should try to live with the
"bad" box until then.
it is not quite as bleak as it sounds. currently, L14 appears to have
been "treated" enough by our HV fiddling that it now, currently, holds HV
up to 3800. this would be sufficient for data taking purposes.
hopefully, this "treatment" will hold until tomorrow. if it relapses to
tripping constantly at 3750, then we may have to replace them today.
hmmmm... a (potential) problem occurs to me. with the neutron wall
installed in the left sector, the subdetector doesn't go out entirely.
as such, i seriously doubt that there is enough clearance between the top
of the wire chambers and the blast coil. remember that we have to use
1-1.5 meter long straight needles to string a wire. the needles bend
some, but, depending on exactly where the afflicted cell lies relative
to the coil, needle bending may not be feasible. the hall just closed
back up, so i can't check this. i guess we'll find out tomorrow...
aaron
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