DQshifter: Beverly

LHO fellows: Evan, Young-Min

Full results may be found here.

• Overall duty cycle: 50%; BNS range: about 70 Mpc
• Bad glitching in the approximately 100 Hz to approximately 300 Hz band appeared on 19 Dec. Investigations suggested it might be due to a problem with the ETMY L2 ESD (coil driver). The hardware was replaced (see the alogs 32730 and 32738). The following day's lock (20 Dec) was short and the effect of the replacement on the glitches was not completely clear. The new coil driver was then removed and replaced with the original one ( 32780). On 21 Dec, the glitching was much better but not completely back to "normal". After some calibration measurements, advice was given by Jeff to veto out the observational data on 20 Dec since the new coil driver introduced a frequency dependent systematic error in the calibration ( 32799). At least one of the loud glitches on 21 Dec shows the same profile in ETMY_L2_NOISEMON as on 19 Dec.
• The 1080 Hz glitches are still present and became very strong on 21 Dec. The cause of this phenomenon is still unknown.
• Some unusually strong transients were seen in the feature at 70 Hz on 20 Dec. According to Robert S., this feature may be caused by elliptical baffles (see 31886).
• The excess noise seen after about 14:00 on 21 Dec is reflected also in the bounce / roll modes.
• There is an interesting discussion of maintenance day activities including turned off phones and a possible remaining phone in the PSL enclosure ( 32783). We were informed that the PSL enclosure phone is definitely off.