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Entry  Fri Oct 4 00:32:24 2019, gautam, Update, ALS, More locking updates ALS_singleArm.pngALS_OOL_20191003.pdf
    Reply  Sat Oct 5 21:26:34 2019, gautam, Update, ALS, Y-end green alignment tweaked ALSY_alignment.pngALSY_OOL.pdf
       Reply  Sun Oct 6 15:23:27 2019, gautam, Update, ALS, Arm control using error signals achieved ALSY_20191006.pdftransitionIRALS.pngarms_ALS.pdf
Message ID: 14938     Entry time: Fri Oct 4 00:32:24 2019     Reply to this: 14943
Author: gautam 
Type: Update 
Category: ALS 
Subject: More locking updates 


I managed to achieve a few transitions of control of the XARM length using the ALS error signal. The lock is sort of stable, but there are frequent "glitches" in the TRX level. Needs more noise hunting, but if the YARM ALS is also "good enough", I think we'd be well placed to try PRMI/DRMI locking with the arms held off resonance (while variable finesse remains an alternative).


Attachment #1One example of a lock stretch. 

Attachment #2ASD of the frequency noise witnessed by POX with the arm controlled by ALS. The observed RMS of ~30pm is ~3-4 times higher than the best performance I have seen, which makes me question if the calibration is off. To be checked...

Attachment 1: ALS_singleArm.png  94 kB  Uploaded Fri Oct 4 01:41:48 2019  | Hide | Hide all
Attachment 2: ALS_OOL_20191003.pdf  19 kB  Uploaded Fri Oct 4 01:41:53 2019  | Hide | Hide all
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