First of all, the conclusions / results from the exercise of the Y arm locking yesterday are:
The position of the beam spots on both ETMY and ITMY are now not so bad ( ~ 5 mm off from the center).
The input PZTs are coarsely aligned to the Y arm.
Nevertheless IP_ANG is still too high to come out from the view port at the Y end station.
After the alignments of PRM, SRM and Michelson, POP is still largely clipped.
(what I did)
- Alignments of the Input PZTs
- Adjustment of the demodulation phase for the Y arm PDH.
- Activation of oplev on ITMY
- PDH locking
(Broken or likely broken stuff)
* IP_ANG doesn't give a signal to the digital side.
* ETMY coils look weak and 2 - 3 times weaker than the other test masses. (or OSEM readout gain maybe lower)
* reload button on sitemap.adl doesn't work.
* Farfalla, a lab laptop, seems out of network.
The Y arm has been locked with the IR beam. The purpose is to use the arm as an alignment reference for the input PZTs.
Detail will be posted later. Here is a picture of ITMY suspension. You can see there is a beam spot in the middle of the test mass.