The short version: Wind (finally, at 50 mph) gave us trouble locking today. I tried some stuff that may have helped, but I need commissioning time (and wind!) to see if it will do any good, but ALS REFL CTRL seems a good IFO witness. Everything is switched back after winds died down.

Travis started have troubles locking when we were having sustained winds around 40 mph and gusts over 50, so I came out to see if some of the stuff we've tried in the past would help. I can't really say for sure if what I've done has helped because winds have now died down, but I wanted to log some ideas. As I found in alog 30547, it would probably be beneficial to push the St1 RX/RY blends down to reduce the amount that the BSCs tilt above .1 hz, so I switched the ST1 RX/RY blends from the normal Quite_250 to the Quite_90 blends. I have also worked on commissioning St2 RX/RY loops (which we don't normally use) that improve the St2 motion at 1-10hz so I tried turning those on. We also use some sensor correction from St1 to St2 around .5hz, which doesn't hurt us when winds are below 30mph, but could couple St1 tilt to St2 motion with high winds, so I tried turning this off. The first 2 attached plots show the EY ISI St2 seismometers and the ground seismometer (which is a better indicator ground tilt than Y motion at these wind speeds).

The first plot shows the St2 RX/RY GS13s and you can see the the table is moving less between .1-20hz (blue is the "high wind" state, red is nominal), while the wind had dropped off  a little (cyan to pink). 

The second plot shows that this improvement in RX didn't make a drastic difference in Y (green is the "high wind" state, brown is nominal), but we gave up a bit of isolation around .5 hz by turning off the St1-St2 sensor correction.

The third plot shows the difference in the ST2 CPS. Below the blend (250mhz) the CPS are a good witness of how much tilt is being injected into the table motion, so at 40  mph it would probably be a good idea to turn this off, if we can lock with more .5hz motion. 

On Monday or Tuesday, I'll try to get a configuration (lower ST1 RX/RY blends, ST1-2 sc off, maybe a hack to get ST2 RX/RY iso loops on) in the SEI_CONF guardian.

I have added a state (and tested the transition while at DC READOUT) to the SEI_CONF called MORE_WINDY that turns off the ST1-2 sensor correction. Operators should try this state (MORE_WINDY) with high winds (40+) and low microseism.

TITLE: 03/18 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Wind
OUTGOING OPERATOR: Travis
CURRENT ENVIRONMENT:
    Wind: 35mph Gusts, 26mph 5min avg
    Primary useism: 0.26 μm/s
    Secondary useism: 0.24 μm/s 
QUICK SUMMARY:

Jim W. is here and configuring SEI in response to the high winds.

TITLE: 03/18 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Wind
INCOMING OPERATOR: Patrick
SHIFT SUMMARY:  First half of the shift was good, but the second half was plagued by high winds.  We had one short lock stretch during a lull in the winds, but the wind picked back up with even more ferocity.  Gusts to ~60 mph for the last couple of hours.  JimW is on site poking at ISI blends in hopes of helping combat the effects of the wind. 
LOG:  See previous aLogs.

Apparently wind is still an issue.  After a brief lull, sustained winds are back above 40 mph.

No issues coming back up.  Winds are still 30+ mph with a few 50 mph gusts, but we managed to get back to NLN.  PI mode 23 has been giving a bunch of alarms since the winds started, but they quickly ring back down (on the order of seconds).  Also have received a few Tidal X and Y error messages, but they don't seem to be affecting locking.

Lockloss likely due to high winds, which were gusting to 50 mph at the time of the lockloss.

Locked in Observing for 11.5 hours.  Wind has picked up significantly since the beginning of the shift (now approaching 40mph) and the range has started to suffer as a result (~50 MPc).  No issues otherwise.

TITLE: 03/18 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 67Mpc
OUTGOING OPERATOR: Ed
CURRENT ENVIRONMENT:
    Wind: 10mph Gusts, 9mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.25 μm/s
QUICK SUMMARY:  No issues handed off.  Observing for the past 7 hours. 

TITLE: 03/18 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 68Mpc
INCOMING OPERATOR: Travis
SHIFT SUMMARY:
LOG:
 

12:12UTC GRB alert. Livingston contacted for confirmation of alert. Both IFOs observing.

7:20 Lockloss - ?

7:57 NLN 

7:59 Checked a2l measurement - looked fine

8:00 accepted damping diffs for ITMY and ETMX as per the whiteboard notes

8:01 Intention Bit: Undisturbed 71Mpc

No alignments necessary. Had to spend time at Locking ALS to avoid repeated locklosses at FIND_IR. No further issues.

TITLE: 03/18 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 69Mpc
OUTGOING OPERATOR: Patrick
CURRENT ENVIRONMENT:
    Wind: 4mph Gusts, 3mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.26 μm/s 
QUICK SUMMARY:

No news is good news
 

TITLE: 03/17 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 69Mpc
INCOMING OPERATOR: Ed
SHIFT SUMMARY: In observing the entire shift. No issues or changes in status to report. Note Cheryl's alog about SDF changes for bounce mode damping if we lose lock.
LOG:

~03:39 UTC Unidentified noise in control room. Sounded vibrational. Lasted for about a minute. HVAC?

No change in status or issues to report.

I analyzed the HWS data for the lock-acquisition that occurs around 1173641000. The "point source" lens appears very quickly (within the first 60s) and then we see a larger thermal blooming over the next few hundred seconds. I've plotted the data below (both gradient field and wavefront OPD). There are a few obviously errant spots in the HWS gradient field data. Since I'm still getting used to Python, I've not managed to successfully strip these off yet. However, it is safe to ignore them.

Check out the video too. Next step is to match a COMSOL model of thermal lensing with a point absorber to the data to get a best estimate of the size of absorber and the power absorbed (preliminary estimates are of the order of 10mW).

FYI: this measurement compares the system before, during and after a lock-acquisition (ignore the title that says "lock-loss"). The previous measurement, 34853, looked at lens decay before, during and after a lock-loss.