Operator: tancredi
CCR tuned beam to a higher current but only 175 mA could b eachived. However
at those currents the "cell temperature" (as reported on the ABS summary
screens on dblast14, not the abs controls, for lack of better definition) was off
scale, meaning close to 300 K.
Also, the Wch trips were just continous and ligit pressure extremely high (4e-7).
Asked for beam at 150 mA while gas is on. VZ updated the temperature sensor calibrations, which did not yield a big change.
At 150 mA ligit started to drop (2.2 e-7 with abs on) and cell temperature went as
low as 160 K. It stayed at 170-180 K for most of the shift. Trips were still quite
frequent and needle was less than 200 C/hr. Slowly things improved, probably
as a result for LLoncoy adjusting the ring RF phase with temperature/current.
Finally took data at almost 300 C/hr.
Quite often we do get horrible fills though.
at 12:00 closed V11 and V14 (manually or from the hall panel) and switched off
nozzle cold head and cryo compressors. Since the nozzle sensor is caput I have
no way to tell what nozzle temperature is right now. Waited 1 hr before turning
RF off (Rf was kept off to facilitate warming up)
With run 13670 started empty target data taking. Ligit pressure was 0.7e-7.
Since now cell T is not really an issue and wch should stay quite, LLoncoy will push beam current back up in steps.
Spin angle still 32. We should go back to 45 !!!!
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:32 EST