This morning, I aligned the 3 stages of OSEMS (14 in total). This involved some clean filing of one fo the middle stage brackets. A month ago, we noticed that this bracket held the AOSEM already at an extreme in height range, however after beating the streets to see what could be done (via SUS engineering and SUS LLO), we decided to leave it and hope we didn't need more range. The recent SRM mass alignment has sent a small differential pitch up the chain causing this AOSEM to now need more height range. Dam*. The bracket itself has slots for additional height adjustment, however the bracket then runs into the side of the AOSEM itself (hence the poor design statement above). Since we can't do much at this point to fix the range, I disassembled the bracket, removed the AOSEM and filed the bracket down where it hits the AOSEM. I used a Class B file. There is another AOSEM hugging the edge of the mechanical range, but I'm leaving it for now.
With improved mechanical range on this one AOSEM, I was able to align it and the rest of the OSEMs. I've run quick TFs in V, L, and R - all look good so the chamber is ready for OFI installation (and for Jason to post final alignment numbers of SRM).
This is how the magnet looked in the UR M2 AOSEM before bracket "attitude adjustment".
This is the bracket-AOSEM mechanical intereference that didn't work today. (Note, we've reported that on many of our HSTS suspensions at LHO these brackets are at the end of their range, it just bit us this time. I do not know why they are all high at this stage, but the suspension pendulum modes match the model so the pendulum lengths are correct. Our last round of diagnosis on this many months ago was hand washed off that the LHO suspension structures were possibly from a different batch than the LLO ones and therefore there is a mechanical difference in how these AOSEMs are mounted.)
And this is the bracket with my hand-crafted AOSEM relief shape which shoulda been in the bracket in the first place.