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AdV-DET (Output mode cleaner)
mwas - 14:12 Thursday 16 August 2018 (42455) Print this report
OMC lock acquisition speed optimization
Summary:
* restored a good speed for the OMC lock acquistion,
5 minutes in total = ~2 minutes to lock OMC1, ~1 minute for DARM hand off to DC signal, ~2 minutes to lock OMC2
The part of full ITF lock acquistion due to OMCs should drop from 50% during latest commissioning run to ~25%.

Increased the temperature ramp speed to what was before the July intervention (0.3 degree amplitude, 0.0005 Hz frequency). So a factor 2 faster for OMC1 and 2.5 for OMC2 than in the past few weeks.
Adjusted the Peltier locking filter gain to be a factor ~2 below oscillation.

Reduced in ITF_LOCK.ini omc1/2_therm_ramp to 5 seconds (from 15 seconds for OMC1 and 10 seconds for OMC2). The automation of the OMC lock should be detecting properly any thermal transient in the OMC, so this shouldn't be needed anymore.

Switched on the SDB1 picomotors. Used the two folding mirrors in front of OMC1 to realign the beam while looking at OMC1 locked on the order 2 carrier mode. This improved the alignment from order 1 and 0 TEM modes of same height, to order 1 mode 5 times lower than order 0 mode.
Switched the SDB1 picomotors off.

Relaxed the condition on OMC temperature stabilization precision before starting a scan in the automation from +/-3mK to +/-5mK.

09:24 UTC locked in LOW_NOISE_3, the OMC2 lock switched to quickly to full bandwidth control with PZT
09:36:40 UTC unlocking ITF on purpose, to check OMC lock again.

Figure 1, Relocking OMCs at 09:51:30 UTC, OMC1 locked at 09:53:30 UTC, OMC2 lock starts at 09:54:25 UTC, OMC2 locked at 09:56:10 UTC
relaxed the OMC saturation check to ensure PZT correction is in +/-7 V instead of +/-5 V

Figure 2, 10:14:40 UTC OMC2 lock ramp starts, 10:16:45 UTC OMC2 locked
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