ITF found in Bad_Weather and LOCKED_ARMS_IR, due to the high wind activity it was not initially possible to proceed with the locking acquisition.
At 22:00 UTC I started to relock and, at 22:56 UTC, the ITF was back in Science Mode.
It unlocked at 23:23 UTC, I tried to relock but due to the strong gusts of winds it kept unlocking at ACQUIRE_LOW_NOISE_3.
At 2:59 UTC the wind calmed down and, after a couple of attempts, it was possible to reach LOW_NOISE_3 again at 4:04 UTC.
ITF left locked

SBE
SIB2 Position loop closed via VPM at 22:00, the horizontal loop opened again at 22:12 UTC during the locking acquisition.

The NCal cancelling line at 36.04 Hz was left by mistake. It was visible during the short look segments of the night. It has been removed at 4:00 UTC.

ITF found in Bad_Weather, high wind activity which was preventing the lock.

After many failed attempts the ITF could reach LN3 at 18:59 UTC; the planned calibrations have been skipped. 

The wind activity increased again and the ITF unlocked at 19:24 UTC.

ITF left in Bad_weather and in locked arms.

CAL

Testing two new NCals

SBE

There are problems with SIB2; today I have recovered the vertical position but thekeep opening. The issue has been already reported in the logbook and to the SBE on-call.

Same plot updated with one week more of data.

Again the same plot, including one more week of data.

Two new NCal have been started around 3 UTC: NEN at 18.02 Hz and NWN at 18.04 Hz (rotor rotation, half of the h(t) signal). The sign of the canceling line might be wrong. It will be checked later today (if the relock is possible). They have been stopped around 4:20 UTC.

The compputation of the NWN temperature has been fixed (it uses a +- 20 V ADC and was configured for a +- 10 V ADC)

In addition, the frequencies of the following lines have been adjusted: NNF: 18.04 -> 18.08, WNN: 18.26 Hz -> 18.22 Hz, WSN: 18.28 Hz -> 18.24 Hz

Taking advantage that we are locked on the IR, we moved the PR vertically (F0_Y_SET by -60 um) to bring the beam on the TX from 14 urad to 13 urad.

The beam is still well centered on the ITMs. (See attached plot).

Today, I found ITF in locking CARM_NULL_1F.  5:22 UTC ITF in SCIENCE. 07:39 UTF ITF unlocked. The ITF status set in BAD_WEATHER due to strong wind and sea activity, which made locking impossible during this shift.

ITF found in Science, BNS Range ~51Mpc
Sea and Wind activity quite high during the shift

• 02:10UTC, ITF unlocked

SBE
SIB2 Position Loop properly closed after opening by the guardian several times:
    23:11UTC, 23:20UTC, 23:33UTC, 23:41UTC, 00:23UTC, 00:33UTC, 00:38UTC, 00:49UTC, 01:24UTC, 01:50UTC, 03:53UTC, 04:04UTC, 04:18UTC

QPD
B2_QD2 galvo loop properly closed after opening, following the closiure of the SIB2 Position loop:
    23:12UTC, 23:21UTC, 23:34UTC, 23:42UTC, 00:23UTC, 00:33UTC, 00:39UTC, 00:50UTC, 01:24UTC, 01:50UTC
03:33UTC, I rearmed vBias of B1p_QD1 and B5_QD2
04:10UTC, I rearmed vBias of B1p_QD1 and B1p_QD2

Guard Tours (UTC):
23:17 - 23:54
01:06 - 01:42
03:08 - 03:45

Since the power observed for the LED of the WEN NCal was again unstable, it has been switched off this morning at 4:03 UTC while the ITF was unlocked. The corresponding DMS flag has been shelved.

ITF found in LOW_NOISE_3 and in Science Mode.
It unlocked at 15:46 UTC, back in Science Mode back in 16:39 UTC.
At 19:08 UTC, similar to yesterday (see report #67221), there was a period of missing data with the same error from SUSP_Fb and FbmFFE.
ITF left locked.

I was able to close the WI ID loop without issues by applying the standard procedure. After that, I removed the Earthquake mode and realigned the cavities. Then I started the lock acquisition, but there was a problem with the north cavity: although it initially locked, the lock was lost after a short time.
At 05:27 UTC, I set Troubleshooting mode and began contacting the ISC on-call and the SUSP on-call. Around 07:00 UTC, I also contacted Paolo.
After some investigation, he discovered an incorrect value for the gname SAT_NI_MAR_ENBL. Once this issue was fixed, we were able to relock the cavities; unfurtunately the ITF keep unlocking in CARM_NULL_3F. The ISC on-call was still connected and continued investigating the problem.

We discovered that this gname can be modified by clicking the "Reallocation" button on the SUSP GUI. We also found that two other gnames were affected: SAT_NE_LOWN_ENABL and SAT_WE_LOWN_ENABL.

In the end, we were able to restore the correct values, and finally, at 10:50 UTC, the ITF was put into Science Mode.

Guard tours (time in UTC)

11:30-12:00
  

ITF found in LOW_NOISE_3 and SCIENCE mode (Autoscience ON); BNS Range ~53 Mpc.
ITF unlocked at 01:36UTC due to end TM (MIR or MAR) correction saturation (pdf 1). WI Guardian opened F0 loops, reflections caused by movement of WI visible on WE_CAM. ITF set to DOWN in EARTHQUAKE mode waiting for WI oscillatons to subside.
Attempted to close WI F0_DC_ENBL at 02:50UTC with no success. Second attempt at 04:02UTC unsuccesful again, ISC on call notified.
Recovered at 05:22UTC thanks to intervention by Berni, lock acquisition in progress.

Guard tour (UTC)
          -> 21:38
23:02 -> 23:45
01:05 -> 01:55
03:02 -> 03:42

ISC
ViolinModes red flag on DMS excited at around 00:50 UTC (fig.1)

When I arrived, locking acquisition was in progress

• 13:31UTC, Science mode
• 19:30UTC, Calibration mode to perform the planned measurements 
  • 19:31UTC, Check Hrec
  • 20:02UTC, ISC injections
• 20:21UTC, back to Science

Guard Tours (UTC):
12:47 - 13:20
15:47 - 16:24
18:12 - 18:47
20:57 - 

Today (Jul 5) around 18:00 UTC I have set back the ASC_SR_TX_SET to 0.022 with a 2 hours long ramp. As it was reset a few hours before by the unlock, and the BNS range has been lower by a few Mpc since that relock.

ITF found in LOW_NOISE_3 and in Science Mode.
At 10:53 UTC there was a temporary lack of channels, while investigating I've found this message on SUSP_Fb: 2025-07-05 10h53m53 UTC frame 1435748051 not send to FbmFFE: sending queue is full.
The ITF unlocked at 12:21 UTC and, after a period of instability of the Injection, it was possible to start relocking at 12:42 UTC.
Relock in progress.

Guard tour (UTC)
04:56 - 5:32
10:12 - 12:40
12:47 -

ITF remained locked in LOW_NOISE_3 with SCIENCE mode (Autoscience ON) for the whole shift; BNS Range ~54 Mpc. 

Guard tour (UTC)
22:35 -> 23:08
00:30 -> 01:08
03:05 -> 03:40
04:56 -

I extended the analysis of the BNS range fluctuations over the past two days to include all _mean and _rms channels from the trend frames (~15k in total). The most correlated channels are those related to B5, i.e., the beam at the dark port before the Output Mode Cleaner. This is probably not informative.

Other notable channels include: V1:Sc_BS_CMRF, the control of the Common Mode Rejection Factor at the Beam Splitter, and V1:Sa_WI_F0_ACC_X, the X-axis acceleration at Filter 0 of the West Input.

Attached:

• The text file with the full ranking of channels showing a Pearson correlation greater than 0.2 (in absolute value),

• and a few plots of the most correlated channels.

Following the analysis done in the past days, which showed correlation between B1p DC (and the B1p beam shape) and the BNS range, we decided to make a scan of the SR tx in order to try to drive this effect.

In the Figure 1 a trend of the test is visible and we can say that for SR tx offset of ~ 0.022

- the B1p DC is minimum

- the OG is lower than the 0 position

- the frequency noise coupling is higher than the 0 position

but the BNS range is maximum; this may lead to a lower mistery noise? to be understood

We leave for this lock a ramp going to the optimal point for SR tx (which will be reset at the next unlock)

I analyzed the LSC noise injections done last Monday, 30/06. In the plots the results on DARM and Hrec.

There is basically no difference with the recent past: CARM is still affecting DARM (ISC recalibration still pending) but not Hrec because of CAL own measurements; Hrec is instead affected more by MICH up to 30 Hz.

Figure 1During the step of the ring heater on June 20 the modes order 7 and 11 have moved in opposite direction, while simple simulations of a single arm would expect for all modes to move in the same direction in the arm FSR, with the change in the FSR smaller for very high order modes as they start to be clipped in the arm.

I have reused the Finesse 3 simulation that Augustin has been developping for scattered light (https://git.ligo.org/augustin.demagny/finesse-simulation-04)  to look instead at the CARM to B1 transfer function. These simulations include a misalignment of SR by 2urad. I have added appertures of 170mm in radius to add realistic losses to very high order modes, and simulated with the max TEM number of 10.

Figure 2 shows the result around the first FSR for a nominal end mirror radius of curvature of 1683 meters, while Figure 3 shows the same for 1679m radius of curvature for both end mirrors. It shows the same effect that the two HOM spanning around the first FSR of the arm move in opposite directions, which is counterintuitive, but similar to what has been observed experimentally on figure 1. Note that peak in the middle of the figure is slightly above 50kHz, while the analytical calculation predicts an FSR with a spacing of 49'969 Hz (slightly below 50kHz). Does this mean that the peak we see is not the FSR, but something else? What is strange is that it remains in the simulation when the max TEM is reduced to 0, so it cannot be the order 9 mode. The side modes around 44kHz and 56kHz, also remain present for max TEM 1, and disappear for max TEM 0, so this is actually two images of the order 1 mode, and then it makes sense that they move in opposite direction when the RoC is changed.

Figure 4 and 5 shows the frequency range of modes order 1-3, respectively for 1683m on EM and 1679m. These modes behave as expected, moving to lower frequency for a shorter radius of curvature.

Figure 6 and 7 shows the frequency range of modes 4-6, the picture is confused with more modes than one would expect. Some of the modes move to higher frequency for a shorter RoC, while others move to lower frequency. In particular the mode around 33kHz, which could be the order 6 mode moves to higher frequency, so the opposite of the low order modes.

I will add the modified code into git under 'high order mode - CARM.ipynb'.

I’m just adding a spectrogram to better highlight the data segment and frequency range affected by this noise issue.

ITF in Science for the whole shift, BNS Range ~53Mpc

VPM
08:35UTC, SNEB_Quadrants process stopped for a mistake, restarted it properly after 1 minutes

Last night, there was a malfunction of the control of one of the NCal that did not correctly measure the rotation speed. This was triggered by a drop of the LED power around 20:45 UTC. This ended this morning slightly before 3:00 UTC. As a consequence, two new lines were present during this period, one at exactly 36.36 Hz, the other one, not very stable, around 39 Hz.

There was another short occurrence of this issue around 8:30 UTC.

To mitigate this issue, we plan to adjust the NCal LED threshold as soon as possible.