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User name Kai
Log entry time 04:56:25 on November 10, 2009
Entry number 298715
Followups:
keyword=run process
We started our production at 00:10am with BPMA=BPMB=(0,0). Left dipole is
still down. Only right arm goes to production. The target alarmed when we
asked for 100uA directly. RC Yi Qiang suspected that it is because the
temperature goes out of the high limit range, so our strategy is to
increase the JT valve accordingly when we ask MCC to ramp up the beam
current from 60uA to 100uA with 10uA as a step slowly. The target runs
well up to 90uA. Once we went to the 100uA, the target is still fine both
when beam is ramping up and when beam became stable, but get alarmed when
beam trips. We saw that the heat power reading reaches to zero on the
strip chart of the high power heat. Then I suspect it is because that we
turn off the local power heater today when there is no beam, but haven't
run it under 100uA beam which might cause the problem. So I increased the
local power heater from 0 to 35V, which roughly corresponds to 100 watts
power supply. We then ask for 100uA again, but the target is still silent
when beam stable, and went to alarm when beam trips. The current target
status is that temperature is within the range 21.5kv~22.5kv which is
good. Cryoflow is stable, and there is 100watts local power supply. And
the pressure is still dropping sharply when beam trips. I'm not sure if
it is a PID problem that it cannot response enough quick to maintain the
target temperature and pressure. As we are running smoothly under 90uA,
which is still a good production, so I'm not going to take risk on 100uA
before JP come here to fix the problem tomorrow.
A copy of this log entry has been emailed to: jpchen