There were six separate locks during this shift, including a new record lock stretch of 25 hours. Typical inspiral range was ~ 75 Mpc. At least two locklosses were caused by earthquakes. Total observation time 57 hours (duty cycle 59%).
Very loud (SNR ~ 1e3) glitches associated with range drops and ETMY saturations continue (roughly 40 during this shift). The correlation between glitches and saturations was investigated; it was found that every SNR > 1000 Omicron trigger (and most with SNR 100 – 1000) was simultaneous with a range drop and an ETMY saturation. Considering the possibility that the 'dust glitches' and the ETMY saturations are actually the same thing. (More detailed alog on this coming soon; details and follow-up at PreO1WorstGlitches wiki).
Spectrograms showed some excess noise in several broadband lines between 10 and 40 Hz on Thursday, and a set of narrower lines between 10 and 50 Hz on Friday. Cause unknown.
The third observation period on Saturday had a significantly higher strain noise floor and lower range (~ 60 Mpc). Robert suggested that this was high frequency noise in an oscillator ( alog). Not followed up.
The periodic 60 Hz glitch which occurs every 72 minutes continues, with slightly lower SNR than during ER7. They are vetoed very efficiently by H1:SUS-ETMY_L2_WIT_L_DQ.
More details can be found at the DQ shift wiki page.
Probably the ~60Mpc segment was due to a calibration issue -- in the previous lock, the OMC-READOUT_ERR_GAIN was off by a few tens of percent, and this will change the DARM loop gain and the calibration. I suspect the gain-matching calculation was off for this lock, too. You can check to see if this was the cause by comparing the height of the calibration lines from one lock to the next. This is something the summary pages can do, but it looks like they haven't been updated for the new line frequencies and amplitudes.
(A source of RF noise had been recently suppressed with a bandpass filter on the 9MHz oscillator, this would not have changed between the locks.)