In our ongoing quest to figure out what causes the ETMX glitch locklosses, I've rerun all O4 NLN locklosses with our most up-to-date locklost code to see if we can pinpoint when it started and how/if it comes and goes.

To do this I made a histogram plot for all of O4 showing the amount of locklosses we had each day in blue, and then over that plotted the number of  those locklosses that have ETMX glitches right before the lockloss (plot). Basically, it looks like it's been with us since the start of O4. There are times where we go a week or maybe almost a whole month without getting locklosses from them, but they're still pretty regular and we see them every few days otherwise. In O4b, it looks like we saw them very often between end of August to early October and then saw less of them in December, but it's also hard to quantify because we had less locklosses in December, but that could've been either due to more time locked, or due to more time when the detector was down (same with November - that was when we had all the NPRO stuff).

I also have this plot as a pdf, and here's the link to my lockloss tool in case anyone wants to peruse the early O4 ETM glitch locklosses. Also keep in mind that a few ETMX glitch locklosses will have been missed being tagged by the lockloss tool - our code relies on the glitch surpassing a threshold and then going back down and staying below another threshold for a set amount of time, but in a few cases the glitch leads right into the lockloss, meaning it doesn't stay below that threshold long enough for the lockloss tool to realize it was an ETM glitch and thus not tagging it. This doesn't happen very often but it's still important to note that there are more ETM glitch locklosses than we have plotted on this histogram.