Operators: Hido, Yasui

Shift time: 9:00-17:00 JST

Check Items: There was no issue on the regular check of VAC, CRY, and TEMP.

(Ikeda-san’s script for comparing cryocooler temperatures was very helpful!)

IFO state (JST):

9:00 OBSERVING

12:33 LOCKLOSS

(While recovering the IFO, there was an earthquake near the Tokara Islands around 12:50.)

13:45 OBSERVING

17:00 OBSERVING

K1CALCS

Channels in JGW-L2314962

It's related to klog#34468
They were updated based on the latest value of optical gain of DARM and ETMX actuator efficiencies in klog#34466.

Changes were accepted on observation.snap (Fig.1), down.snap (Fig.2), and safe.snap (Fig.3).
Finally, numerical rounding errors were reverted after re-loading observation.snap as shown in Fig.4.

I updated line tracking parameters (JGW-L2314962).

All detected changes are coming from the planned commissioning activities.
- Chagens in foton Fig.1 are related to klog#34466 (k1calcs).
- No changes in guardian (Fig.2).
- Changes in SDF tables shown in Fig.3-4 are related to this klog#34467, klog#34469 (k1calcs), and klog#34464 (k1calex, k1caley).
- No changes in the model (Fig.5).

Finally, I raised CFC_LACTCH and IFO guardian moved from CALIB_NOT_READY to READY.

CAL group

We did the calibration measurements and update the prameters.

Estimated parameters in the Pre-maintenance measurements are as follows.
 H_etmxtm = 3.840823152e-14@10Hz ( 0.04% from previous measurements)
 H_etmxim = 1.546766367e-14@10Hz  ( 0.70% from previous measurements)
 Optical_gain =  2.114710228e12         ( -0.69% from previous measurements)
 Cavity_pole = 18.100765775 Hz           ( -0.15% from previous measurements)

Previous values are listed in klog#34424.

Fig. 2 and Fig.4 shows the ratio of the sensing functions estimated.

Estimated parameters in the Post-maintenance measurements are as follows.
 H_etmxtm = 3.839861341e-14 @10Hz ( -0.03% from pre-maintenance measurements)
 H_etmxim =  1.484142700e-14@10Hz ( -4.05 % from pre-maintenance measurements)
 Optical_gain =  2.126367691e12         ( 0.55 % from pre-maintenance measurements)
 Cavity_pole = 18.041050536 Hz           ( -0.33% from pre-maintenance measurements)

k1calcs

I accepted the following SDFs in observation.snap, down.snap, and safe.snap.
This is caused by calibration measurements.

Date: 2025/07/04

Member: Misato Onishi, Keisuke Sakanoue

We performed our usual WSK calibration at UToyama.

The results look no problem.

Results

Comparison with Previous Results

Comparing with previous results, no significant issues were found.
Attached graph is the result summary including the latest measured data.

We accepted the SDFs reported on klog34463.

CALEX, CALEY

K1:CAL-PCAL_{EX,EY}_TCAM_{MAIN,PATH1,PATH2}_{X,Y}

A CAL Tcam session was performed to obtain beam position information necessary for Pcal. The parameters have already been updated, and SDF has alreadly been accepted.

Operator: Shingo Hido, DanChen

Update Time: 2025/07/04 16:16:28

Update Time: 2025/07/04 16:17:06

Update Time: 2025/07/04 16:17:41

Update Time: 2025/07/04 16:18:19

With Shingo Hido, Hirotaka Yuzurihara

This afternoon, during the Pcal Tcam session, the EYA Tcam stopped and could not capture images. An error message was displayed on the screen: "An error occurred while capturing frame for ZWO ASI294MC."

As a countermeasure, "Recovery" and "Force" under the "Recovery" menu were executed, but a GRD timeout error occurred and recovery was unsuccessful.
After manually setting the GRD to "DOWN," executing "Recovery" - "Recovery" restored normal operation.

If the same error occurs in the future, setting the GRD to "DOWN" before attempting recovery may be an effective procedure.

Kimura and Furuyado (Shinkoh Denki)
 In order to repair the insulation defects caused by rust in the distribution board PLX-129,
we confirmed the replacement procedure and the on-site situation.
(See attached photos.)
Based on the results of the check, a distribution board repair plan will be prepared and the repair will be implemented.

With Takahumi USHIBA

Purpose and Overview

• Due to tidal motion, an offset gradually accumulates in the feedback signal applied to the IP (Inverted Pendulum).
• The purpose of this work was to offload this offset before the IP feedback signal saturates.
• Because there is LPY coupling, the offloading causes a drift in the PY alignment of ETMX. Therefore, after offloading, the PY alignment was manually adjusted to maximize the green transmission, and the good oplev setpoints were updated accordingly.

Procedure

1. Request RESET_ASC_FEEDBACK and DOWN to LSC_LOCK
   This was necessary to correct the alignment and set all suspensions to LOCK_ACQUISITION.
2. Monitoring TM Oplev and Green Transmission
   TM oplev signals and green transmission were monitored during the procedure.
3. ETMX-IP-ISC2LVDT Filter Bank
   Opened the filter bank of ETMX-IP-ISC2LVDT.
   The objective was to bring the output signal to zero.
   Set the ramp time to 100 seconds.
   Set the gain to 0.
   Waited for 100 seconds.
   Observed that the green transmission decreased (flash level dropped to around 0.4), which was too low for locking.
   Pressed Clear History.
   Restored the ramp time to 3 seconds.
   Restored the gain to 1.
4. Recovery of Green Transmission by Adjusting TM Oplev Setpoints
   Manually adjusted TM oplev setpoints referencing the green transmission value.
   After adjustment, the green transmission recovered to approximately 0.9.
5. Updating Good Oplev Setpoints
   Updated oplev setpoints to reflect the adjustments made during this work today:
   Pitch: 37.2 → 39.1
   Yaw: –9.26 → –1.76
6. Lock Trial
   Performed a lock acquisition trial.
   Successfully achieved lock.

I took the TCam photos for four mirrors at 9:09 ~ 9:19 this morning. The previous work is klog34382.

• ETMX
  • original
  • fitting result
  • previous reference
• ETMY
  • original
  • fitting result
  • previous reference
• For these mirrors, I updated the reference positions. I also re-draw the yellow line shown at the k1mon4. For the other mirrors, we don't need to update the reference positions.

We accepted the SDFs reported on klog34454.

CALEX, CALEY

K1:CAL-PCAL_{EX,EY}_TCAM_{MAIN,PATH1,PATH2}_{X,Y}

A CAL Tcam session was performed to obtain beam position information necessary for Pcal. The parameters have already been updated, and SDF has been accepted.

Operator: Shingo Hido, Dan Chen

Update Time: 2025/07/04 09:03:40

Update Time: 2025/07/04 09:04:08

Update Time: 2025/07/04 09:04:49

Update Time: 2025/07/04 09:05:15

After checking the updated PDF, it seems that all three peaks in question (1st No.2, No.6, and No.9) have issues in the fitting results. I plan to adjust the settings to use a longer FFT length and reanalyze them.

output from check_IFO_status.py

Operators

Takaaki Yokozawa, Hiroshi Takaba, Dan Chen

Shift Time

9:00–17:00 JST

Check Items

• VAC: No issues were found.
• CRY cooler: No issues were found.
• Compressor: No issues were found.
• OBS INTENT: The OBS INTENT was ON throughout the shift.

Note

• There was a period when the interferometer did not lock for an extended time. Just before the unlocked duration reached one hour, an earthquake occurred.
• After that, earthquakes continued to occur sequentially.
• Related klog: klog34448

Today, IFO could not be recovered to even RF-locked state automatically by the guardian for a long time (more than 1 hour).
Since this is the first time that IFO could not be recovered automatically during O4c observing run, I investigated the reason.

Figure 1 shows the ETMX OpLev values before and after the final lock of the interferometer.
Though pitch and yaw values were recorded well, LS oplev values were changed a lot.
This is probably due to the DARM control feedback signals, so it is hard to control.

To avoid the same instability, what we can do is
1. Record LS Oplev values of ETMX and move suspensions so that LS OpLev values becomes close to the one before lockloss.
2. Move ETMX angle during the lock acquisition so that arm alignment becomes good, for example by ADS using GRX.
3. Decouple L2P and L2Y more to reduce the misalignment when LS OpLev values are changed.

Since there are several advantages and disadvantages in the above 3 countermeasures, we need to consider what kind of treatment should be done.

According to klog32643, the peaks got the very high Q values seem to be violin mode:

• Peak of 1st No.2: "EYIMP"

• Peak of 1st No.6: "IYIMP"

• Peak of 1st No.9: "EXIMP"