Operators: nikolas seely tong
plan this evening was to redo the bump study from monday. first tried going to horizontal bump of +2.0mm. after optimizing the slits for this beam position, got very good BQM rates (about factor of 2 or less more than with no bump), but trigger rates were far too high (dead time > 90%). moved to a bump of +1mm (horizontal) and reoptimized the slits. BQM rates were close to the rates for no bump. when we first started this, trigger rates were high (dead time still around 90%), and wc s/n was bad ~1.1 in the first chamber. turned the wire chambers off for an hour and came back online. s/n is much better now (~2/1 in the first chamber) . somehow, trigger rates had changed, and were similar to rates with no bump. chief operator confirmed that the bump was at +1mm (horizontal), so not sure what changed.
lifetime/Imax for +1mm bump was 16min/80mA,
BQM rates: (ULDR) 52,15,12,7
rates for 0 bump:
BQM rates: (ULDR)86,17,12,13
rates for phys0 and bphys0 were:
+1mm bump, before chambers off:
phys0 2500 bphys0 156
phys1 1500 bphys0 90
...
0 bump, before chambers off:
phys0 350 bphys0 200
phys1 270 bphys0 120
...
+1mm bump, after chambers off
phys0 440 bphys0 150
phys1 400 bphys0 150
plan for tonight: continue bump scan. finish +1mm bump. then do -1mm(horiz) and +/-1 vertical bumps. take roughly 1/2 shift of data at each setting. for each setting, once the bump is set, optimize the slits for that setting.
JS
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