Tonight, we transitioned CARM and DARM to IR signals, took loop transfer functions, and determined that we could engage the LSC boosts (FM4 in the CARM and DARM servos, which are the same as the XARM and YARM servos).
Q is preparing spectra to post, and I will dig out time series. Look for these tomorrow, if they aren't posted tonight.
For the time series data fetching, I have taken notes on what we were doing when, so that I can actually find the data.
11:09pm: CARM's LSC boost on for the first time
11:14pm: DARM transferred to AS55Q
11:21pm: DARM's LSC boost on for the first time
11:53pm: CARM transition
12:02am: DARM transition done, both LSC boosts on
12:04am: lockloss after reducing CARM digital offset to 0.4
12:45am: PRMI + 2 arms flashing, with no CARM or DARM offsets (arms still on ALS) because we forgot to put in the CARM offset before restoring PRM alignment. PRMI may have been actually locked, or we may just have been flashing....need to look through the data to see what our recycling looked like.
1:05am: pretty smooth transition completed (both CARM and DARM), but we lost lock while reducing the CARM offset.
1:19am: lockloss - why?? We were just sitting at a CARM offset of about 1.3nm (1.3 counts), holding on IR signals. We were not touching any IFO things while looking at some plots, and just lost lock. Want to see if we can understand why.
1:27am: another nice smooth transition for both CARM and DARM to IR signals, but almost immediate lockloss when reducing the CARM offset.
Using the new ALS lock acquisition scripts (elog 9816) and our transition scripts, getting back to PRFPMI lock is pretty smooth and procedural.
* Align arms using ASS (ifo configure screen, restore xarm and yarm, run both arms' ass scripts).
* Align PRMI, no arms (ifo configure screen, restore prmi sideband)
* Find ALS beatnotes, with arm lasers on opposite sides of the PSL. For both, when increasing the value of the temperature slider, the beatnote should increase in frequency. (ifo configure screen, restore CARM and DARM als)
* Run ...../scripts/ALS/Lock_ALS_CARM_and_DARM.py
* Run "Find resonance" scripts from ALS screen for each arm.
* Put in a 3 count offset to CARM loop.
* Restore PRM alignment. (PRMI should acquire lock immediately, although PRM may need some small alignment tweaking). Enable PRCL and MICH outputs, PRM and BS actuation outputs.
* Reduce CARM offset to 2 counts.
* Set offsets of 1/sqrt(TRX) and 1/sqrt(TRY) filter banks in the AUXERR section of the LSC screen. The outputs of both should equal 2 counts (to match the 2 count offset in the CARM loop).
* Run .../scripts/PRFPMI/Transition_CARM_ALS_to_TransSqrtInv.py , making sure to reduce the CARM digital offset if needed, to keep the arm transmissions at about 0.1 counts.
* Engage FM4 of the CARM filter bank, which is the LSC boost.
* Run .../scripts/PRFPMI/Transition_DARM_ALS_to_AS55.py , making sure to reduce the CARM (or should be DARM?) digital offset if needed, to keep the arm transmissions at about 0.1 counts.
* Engage FM4 of the DARM filter bank, which is the LSC boost.
Notes for going forward:
When we have small-ish digital CARM offsets, such that both of our arm transmitted powers are about 0.1 or higher, we see clear coherence between our CARM_IN1 (the 1/sqrt(trans) signals) and a normalized REFL11_I (again using a spare filter bank like XARM to get REFL11 normalized by (TRX+TRY) ). We have not yet tried transitioning the CARM digital error signal to this normalized REFL11.
Even though we see that the IFO is much less noisy (as measured by significantly reduced RIN in TRX and TRY as visible by eye on Dataveiwer), we are still losing lock when we reduce the CARM offset. I have noted above several times, for when we had locklosses, so that I can see if I see anything elucidating in the time series data.