DQ Shifters: Riley McNeil and Emil Lofquist-Fabris.

• Daily observing duty cycle: 57.91%, 38.96%, 38.57%, 51.84%, 53.67%, 89.90%, 55.83%. Week average: 55.24% Observing.

• This week was plagued by earthquakes, most notably the 8.8 magnitude earthquake from Russia and its subsequent aftershocks.

  • These really hindered the duty cycle of the detector.

  • The elevated ground motion in the earthquake band appears to be related to light scattering just above 20 Hz.

• BNS range was consistently around 150-155 Mpc throughout the week, with 1 exception being on Sunday, when the detector ran without the squeezer for 2 and a half hours, dropping the range by about 15 Mpc.

• There were also multiple days where the SQZ had issues staying locked, causing the detector to drop out of observing.

• Throughout the shift there has been recurring glitching/noise in the 20-40 Hz range, seen both in the glitch and strain plots. However, they were less significant in the last two days.

  • This has been seen in previous shifts, however relatively inconsistently.

• There was a recurring spike in noise in the H1 Y-manifold beam tube motion [X] at the exact same time every day this week (right after 17:00)

• For the first 4 days of the shift, there was a recurring noise from ~11:00-13:00 in the corner station accelerometers (all degrees of freedom), however starting Friday it stopped showing up.

• There was a low chi-squared PyCBC trigger that appears to be a blip, with the new SNR being the same as its original SNR on August 2.

See the full report here: https://wiki.ligo.org/DetChar/DataQuality/DQShiftLHO20250728