Today is a relatively quiet day for ground motion- no earthquakes and the microseismic motion has been mostly below the 50th percentile, according to the BLRMS screen in the control room. I took a deeper look at the locking patterns to see if I could see any change in locking success. From a purely subjective point of view, locking the IFO to the point of being able to do commissioning work is a time consuming process because there can be so many locklosses.

Here is some actual data from today:

Within a 2 hour and 10 minute period, there were 37 lock attempts. Commissioning work essentially begins once the IFO reaches the PRFPMI locked with 3F state (guardian state number 1200). At this point, the PRMI is moved to the 1 FSIG sensors (state 1205), and then the ASC WFS can start the engagement and testing. Out of those 37 lock attempts, only six lock attempts actually achieved guardian state 1200. Of those 6 PRFPMI lock successes, only five allowed commissioning work- one lock reached state 1200 and then immediately lost lock after.

Of those final five locks where commissioning took place, four of the locklosses were caused by commissioning work (testing new loop engagement strategies). One lockloss appears to have occurred independent of the ASC work- ASC was in a steady state at the time and there was no oscillation in ASC preceding the lockloss.

I think that it would be beneficial to spend some time investigating why the locking process is so slow and so fragile. Commissioning will cause locklosses, but based on this one period of investigation, that only accounts for 13% of the locklosses. It also doesn't seem like these locklosses can be explained by ground motion. The PNC for the X arm has been enabled for all of these lock attempts.

I have attached a plot of the LSC LOCK guardian state number, marking the period of time I chose to do this quick analysis. It might be worthwhile to note that a majority of these locklosses seem to occur around state 1005- Engage PRMI 3F. It will probably also help to set up some programs that can collect actual statistics of the locklosses, so bigger trends can be investigated.