Locking green arms: did green arms manual and mostly touched up ETM P and TMS P.

 

ALS COMM had some trouble finding IR so started an initial alignment. 

 

It looked like the camera servo was taking the Y arm to a bad alignment, but looking at the ALS Y camera the spot looked nice, it was just very clipped. I was able to recover the power on ALC-C_TRY_A_LF by aligning the beamsplitter. See first attached screenshot. So we thought there was a problem with the camera servo but again it was just alignment onto ISCT1.

 

During the MICH_BRIGHT part initial alignment ISI_BS_ST2 watched tripped. Untripped it, re-requested SEI_BS to FULLY_ISOLATED_NO_ST2_BOO. It tripped again so I did the BS alignment by hand - minimizing the dark fringe while looking at AS_A_DC_NSUM as MICH swung around. Manual’d the INIT_ALIGN guardian to SRC_ALIGN. 

 

After this fairly elaborate initial alignment things looked much better, arms locked, IR was found, DRMI acquired extremely quickly.

 

Changed CSOFT gains in the guardian so that we acquire with the gains that we tweaked at power 25W (alog 58813). The CSOFT_P gain used in ENGAGE_SOFT_LOOPS is defined in lscparams. The CSOFT_Y gain is in POWER_25W. I forgot to reload the guardian in time, and had to change the gains by hand in this lock, so this is untested while acquiring lock.

 

Changed REDUCE_RF9_MODULATION_DEPTH state number from 570 to 510 so it would come after POWER_25W in the guardian. Made edge cases from POWER_25W to Reduce_RF9, and from reduce RF_9 to MAXIMUM_POWER so we can do less manual’ing around. In this particular lock I accidentally did reduce_RF45_modulation_depth which we’ve been skipping lately. Anyway, now if you request MAXIMUM_POWER it should go from POWER_25W to REDUCE_RF9 to MAXIMUM_POWER.

 

I tried out MAXIMUM_POWER with the O3 wait times and convergence checkers in place, all I changed was the power it would go to - 47W. It went up extremely quickly - from 25W to 47W in less than 3 minutes. It was scary but it worked!

 

I think this lock will be a nice one to look at ITMY absorption on the HWS. See second and third attached screenshots for some times and the HWS image and spherical power. I see some kind of signal on the ETMY and ITMX (??) HWSs as well, but nothing so clear as ITMY.