today with Alice, we planned to do a long run with ~80kW in the FPC to check if the lock problems are coming from the interaction with the machine or not.
the goal is to check this assumption on a full day comparable with a day of X-ray production.
we started the amplifier at 10am.
during a move of MaY (injection mirrors of the FPC), we observed a sudden total loss of resonances...
the reason was an abnormal displacement of the motor despite the fact the measured position was reasonable.
we already observed an issue like that....
to fix the problem, one just had to move back MaY.
the cavity started to be locked at 11:15am
the RF frequency has been changed to 500.09595MHz equivalent to 33.33973MHz
but we don't have a beating signal @ 500MHz => one will ask to Vincent to fix the issue.
laser motor CH0 : 1.503453 mm
laser moror CH2 : - 50µm
~ 83kW at 12:30pm
| Ronic Chiche wrote: |
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at the begining of the day, we started to get ~81kW in the FPC for 33% amplifier ratio and after ~1h, we got 84kW after CEP and alignment tuning.
at the end of the day, we got 89kW without walking alignment.
we tried to improve a bit the robustness of the FPC and RF locks:
see the capture for the new locking parameters.
| Ronic Chiche wrote: |
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the RF frequency changed from 500.1003MHz to 500.0913MHz => it reduced by 9kHz @ 500MHz which is equivalent to 600Hz @ 33MHz (we measured 500Hz @ 33MHz). the electron orbit length increased, so we have to increase the cavities length => increase motor values by ~ 68µm.
for the laser cavity : 1.496 560 mm => 1.564 560 mm
the initial values for the motor of the FP cavity are : MOT.03=-130 000 steps and MOT.06=-900 000 steps.
68µm is roughly 11 000 steps (6nm/step) => MOT.03=-130 000 steps and MOT.06=-889 000 steps.
optimum CEP position : -210.8µm => -192µm
I got 80kW in the FP cavity after CEP and walking alignment
then, 82kW after waiting 3h.
then, 84kW after waiting 5h.
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