Much of the afternoon was spent increasing our arm circulating powers, while holding fixed at 50W injected to the vacuum (so about 40W into the PRM).  Between the spot move and CO2X annular heating, we've increased our arm circulating powers from ~240kW to ~260kW while injecting 50W to the vacuum.

Two plots are attached, and they are both a bit hard to read, but I hope that if someone needs to look further, they can use the timestamp on the ndscope for their own zooming-in-ing.   The first shows the lock at 50W where Camilla and I moved spots around.  The second shows the lock where Elenna, Varun, and turned up the CO2X annular heating (during which time the spots were already at their new positions). 

Earlier today we noticed that we do indeed seem to have some point absorbers on ITMX (alog 62598).  This lead us to wonder about moving our spots on the ITMs. 

• Since ITMY looks very nice and free of point absorbers, I changed the ADS to dither ITMX for dof2, rather than using ITMY.   This made it easier to change the ITMX A2L gains so that I could move the spot on ITMX. 
  • I also had dither lines engaged for ITMY, and was roughly changing the ITMY A2L gains to minimize the peaks in DARM.
• For methodology, I was trying to look at the HWSx (newly aligned and working, thank you Camilla!), and see that when I made a spot move, that the beam position on the HWS was roughly the direction I wanted to go.  That worked pretty well, although it's much better if one waits to look after things have thermalized at the new spot position.
• After getting some improvement from moving the spot on ITMX, I moved the spots on the two ETMs, to see if there was a better place that matched the new ITM spot positions.  The increase in powers around -4h on the spot_Moves.png is the big win from the ETM moves. 
• I did another iteration checking on the ITM spot positions, and then the ETMs, but I got into diminishing returns, and stopped.

I have put the new spot positions into lscparams, and we have now locked with them twice.

Since we still weren't getting circulating powers as high as we had been during our commissioning period last spring (where we had ~280kW circulating) and Varun pointed out that our REFL_A_LF was increasing quite dramatically, I wondered if some TCS might help.  Camilla and I had found last week that CO2Y didn't do much good for us (alog 62509). Since CO2X is newly aligned, we gave that a try!  We started with annular heating, with the thought that there is already extra central heating due to the point absorbers. It seemed to pretty clearly do good things, although when I cranked it up from 1.5 W requested to 3 W requested, we seem to have gone past a peak.  I think that we should try CO2X annular heating with ~2W requested. 

We think that having the CO2X annular heating on is a good thing, and we've successfully locked once with it left on, so we're leaving CO2X on.  Just kidding.  The guardian flipped the CO2 mask back to central heating which I didn't realize, so that's what it was using during that last lock acquisition.  After we arrived at 50W, things started to look really bad, and then we lost lock.  It was only after we lost lock that I realized it had put the wrong mask in.  So, tomorrow I'll look at the guardian and make sure that it leaves the CO2X with the annular mask in place.  It would be nifty if we could just leave it on always, but that may make acquisition challenging, so we may need to turn it on once we're at full power and partially thermalized.

With the new spot positions, Camilla and Ryan noticed that the ITMY modes 5 and 6 seemed unhappy with their nominal gains.  I thought that I saw the modes ringing up a teensy bit on my next lock, so I put in their gains (alog 62602).  Those seemed fine, although we weren't locked for a long long time.  Since we lost lock and are relocking, and I don't want to watch them all night, for tonight I have set lscparams to leave gains of 0 for both mode 5 and mode 6.  This should be re-looked at tomorrow.