Operators: karpiusp mcilhany ----
Running completely tensor pol D2 flipping target spin and beam helicity to achieve the combinations:
target: beam helicity:
T+ +
T+ -
T- +
T- -
with each run (i.e. NOT fill) containing only one of the above states.
At beginning of shift:
BQMs: U = 156, D = 54, L = 112, R = 70 @ 65.8 mA
Max fill current: 110 mA
Lifetime: 7 minutes
PHYS0 Rate: 120/82 Hz/mA
Gas: D2 @ 60 sccm
WC signal:noise = 2:1
0015 - Noticed LIGIT rising from nominal values. Also, beam lifetime affected
(got worse).
0020 - sealed off the ABS from the target chamber (closed valves 11,14,15)
0030 - saw high BQMs (~doubled) and ligit rising sharply - asked CCR to retune.
Set detector to "exp disable" and auto ring disabled
0105 - Situation worsening - even AFTER closing the ABS from target chamber AND the beam was off. Vacuum technician called. Situation immediately
improved (without touching anything!).
0205 - Situation got worse again and Brian ORourke was called in.
0300 - Target temperature has steadily been rising since midnight. Currently
at 140K. Called Genya Tsentalovich about what to do. He suggests
checking that the target cell compressor is working - ACCESS - it was.
Set point on target cell controller has been set at 100K the whole evening.
The %power of the heater has been randomly jumping around from 0% to 100%.
0400 - After Brian's initial analysis, nothing wrong could be found except that
LIGIT and IG103 and IG104 were high. He suspects that the target cell is
to blame.
0415 - Call put into Ernie Ihloff about suggestions. He suggests heating cell
to 300K. ACCESS - comrpessor to target cell turned OFF. Target cell
controller setpoint set to 300K. Now we wait a few hours until cell is
heated and presumably the ice that is suspected to be on the cell is
evacuated.
0750 - Still heating up cell, currently around 255K. Plan is to reach 300K and
then cool it back down to 100K, with the hopes that remocingthe ice layer
will have solved the problem.
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:29 EST