They have almost totally worked with detectors on forward
carriage. I have no info on the others. I believe that
scin installation is not yet complete and must wait for
the drift chamber wire removal exercises to end before
work can be completed.
Info regarding the June data...
-There are 8 scins which never read out correctly. They have
replaced all known bad tubes, so these are thought to be
electronics problems of some sort. They will be fixed
in the next month or so.
-High voltages changed regularly throughout the run. This
is not felt to be of major importance for the accuracy we
require. I believe that's right.
-Pedestals are measured for all tubes and included in the
database. Values are about 600 ch. and are NOT subtracted
for the data shown in CED. Pedestals show small time variation.
-The left and right tubes of all scins have been gain matched
within 10% by Simon Taylor.
-The time walk correction factors were measured by Latifa E. and
are presently included in the recsis database. They make
small improvements in the timing accurasy.
-The counter-to-counter offsets are the biggest problem in
the present data set. Those offsets are typically a few nsec.
They will be determined over the next week or two (by a
combination of John Ficencic and Maurik Holtrop) and
then included in recsis. So, you can ask them about that.
-There were times toward the end of the June run when entire
fastbus crates were off for at least a shift. No specific
runs are known yet, but you should be aware of the possibility
of major problems.
It would be nice to know what the present timing resolution is,
but no one has yet measured it. The best *guess* among the experts
is "about a few nanoseconds". They expect accuracy of about
1 ns after application of the next round of corrections.
They are aware we are one of their major consumers and realize we
need a solid 1-2 ns accuracy as soon as possible to enable accurate
time-based tracking.
regards,
Steve