Camilla, Oli

We were wondering what the bias had been during O3, as compared to the amount of ETMX glitch locklosses that had occurred during O3. We referenced Iain Morton's presentation, slide 17. Ignoring the 'SAME' lockloss tags since we know those were caused by the PSL glitching, we found that only 5% of the locklosses from O3b had an ETM_GLITCH tag, while 15% of the locklosses from O4a (plus a bit of O4b) had an ETM_GLITCH tag. Since the method in use at this time for finding ETMX glitches wasn't very good at catching the smaller glitches, we can guess that both percentages may actually be a bit higher, but either way, the percentage of locklosses from ETMX glitches during O3b were much less. We decided to look at what the ETMX bias was during O3b and how that compares to the bias we've been using throughout O4 (until it was changed on Monday 86027).

For all of O3 and up until February 28, 2023 (67698), we had been at a bias of around -450, and then after that date we changed to a bias of around +130, which is what we've had for all of O4 up until a couple of days ago.