Dear colleagues.
this night's shift was a debugging shift, unfortunateley again with no
useful data.
CCR provides improved beam with BQM TBLR=180,50,120,90, with slits at
LRTB=-8,8,2,-8. Max. injection 100mA, lifetime 15-20 min.
/scratch/dblast07 appeared to be full, runs pro2003-01...99.dat removed
after checking that they are all identically present on spuds (see
md5sum-* on ~blast/ ).
Again like last night, a lot of noise showed up in the wire chamber when
displaying events with nsed.
Noticed that the Coda event rate was constantly about 170 Hz, independent
of ring current (!). Also, the coda event rate differed very much from the
PHYS* and BPHYS* rates shown in visual_scal. Further analysis showed that
170 Hz event rate was also stable against change of trigger settings
(varied between elastic_only, elastic_coinc, elastic_een and physics, and
with a highly biased craptrigger.settings.
At 3am, CCR optimized beam quality a little more, resulting in
BQM TBLR=140,40,100,70, with slits at LRTB=-6,8,1,-8. Max. injection
100mA, lifetime 15-20 min.
Still, nsed shows Xmas trees. Noticed that in most triggered events less
than two Tofs have fired (either one or none).
Doubting if a poor beam quality is really the reason for the noise events.
Requesting to switch off the beam, we find that still we have 170 Hz event
rate and Xmas trees (run #481). This is also the case after switching off
the Wch HV's (run #483).
Assuming we have a problem with the Trigger Supervisor (TS), we
power-cycle the VME crate in rack 4 (didn't help)
Noticing that there are Camac problems (cnaf 1 23 0 0 etc.), we reset and
power-cycle also the camac crates and the VME crate in rack 3.
Still, Coda takes data without beam and Wch off at 170 Hz, nsed showing
Xmas trees. We have no further idea and wait for Karen and Doug to come
in.
Hall not yet open, not until technicians are ready to work on ion
polarimeter.
Regards,
Michael and Aaron
--+-------------------------------------+--------------------------+ | Office: | Home: | |-------------------------------------|--------------------------| | Dr. Michael Kohl | Michael Kohl | | Laboratory for Nuclear Science | 5 Ibbetson Street | | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 | | Middleton, MA 01949 | U.S.A. | | U.S.A. | | | - - - - - - - - - - - - | - - - - - - - - -| | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de | | Work: +1-617-253-9207 | Home: +1-617-629-3147 | | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 | | http://blast.lns.mit.edu | | +-------------------------------------+--------------------------+
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