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MIF (ASC)
tomotada.akutsu - 21:48 Thursday 09 January 2020 (12443) Print this report
PRMI's MICH's ASC loops are closed! (locked?)

Kokeyama, Ushiba, Akutsu

Achieved to close/lock the ASC loops for MICH of PRMI. Fig 1 shows spectra of the error signals relevant to the ASC loops; the red ones were measured with the loop on, while the blue ones with loop off (the diaggui file was saved at the place entitled on the top of Fig 1). The UGFs of the loops would be 0.3Hz and 0.2 Hz for pitch and yaw, respectively, but we would need to do furthur investigation including direct measurement of the open-loop transfer functions and so on to confirm that. During the lock, RF90's sideband buildup (K1:LSC-POP_PDA2_RF90_I_ERR_DQ) was (relatively) stably around 0.6 or higher.

The implementation of a gurdian script is mostly done but still on the way (maybe there are bugs), and will be completed soon hopefully...  -> Now (mostly) finished by Kokeyama-san just before we left the control room (?)

 

Note; about the PRMI lock itself; it seems the PRMI LSC lock can be easily closed some time, but not some time... maybe the alignement of the mirrors would be related, but judging from the RF90's sideband buildup flashing, the alignment seems not so bad even when the LSC loop is in hard time to close the loop... hmm...

Images attached to this report
Comments to this report:
keiko.kokeyama - 21:54 Thursday 09 January 2020 (12445) Print this report
Thanks to the great new phasing method, the AS WFSs respond so well for the BS motion! See the attachments. The right bottom panel is the BS oplev, moving around for testing. Most of the WFSs respond well. The best one is AS WFS1 28Q. (We tuned all the four phases on AS WFS1 RF28 so that the BS signals go to Q. The used script is /users/Commissioning/script/asc/rotate_demod_phase.py.)

Nakano-kun, we left PRMI lockd with these MICH ASC loops. I hope they will last.
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keiko.kokeyama - 22:39 Thursday 09 January 2020 (12446) Print this report
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