Time stamp of the visitors(27+2 pepole) who entered center preroom and xarm.
(Monitored with Ikeda-san.)

15:00? center preroom
15:22 center parking area
15:24 Xarm in
15:30 Xarm out
15:30 out of mine
15:40 Mine shutter closed
 

We turned ON the OBS INTENT flag around 18:49 JST, June 27, 2025 after the approval of Ushiba-san.

CAL group

We did the calibration measurements.

Estimated parameters taken while visitors were present are as follows.
 H_etmxtm = 3.850142293e-14 @10Hz ( 0.52% from previous measurements)
 H_etmxim = 1.621508136e-14 @10Hz  ( 3.2% from previous measurements)
 Optical_gain =  2.126800024e12         ( 0.63% from previous measurements)
 Cavity_pole = 18.183601559 Hz            ( -0.16% from previous measurements)

Previous values are listed in klog#34310.

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

Post-tour measurement results (inside the mine) are as follows.
 H_etmxtm = -3.830386471e-14 @10Hz ( -0.51% from above measurements)
 H_etmxim = -1.565605347e-14 @10Hz ( -3.44% from above measurements)
 Optical_gain = 2.127919074e12           ( 0.05% from above measurements)
 Cavity_pole = 18.267333924 Hz            ( 0.46% from above measurements)

The parameters were updated based on the results from `0627/1606`.
From the current results, it is assumed that the influence of visitors is minimal (at least, no variations larger than the weekly fluctuations were observed).

All detected changes are coming from the planned commissioning activities.
- Changes in foton Fig.1 are related to klog#34393 (k1calcs) and klog#34386 (k1omc).
- Changes in guardian (Fig.2) are related to klog#34386 (k1omc).
- Changes in SDF tables shown in Fig.3 are related to klog#34393 (k1calcs), klog#34386 (k1omc), and klog#34391 (k1calex, k1caley).
- No changes in the model (Fig.4).

As a result of our discussion in the CAL group, we decided not to update the line tracking parameters this time.
This line tracking is for online use only and does not affect the LL.

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

We accepted SDFs related to the weekly cal measurement.

CALCS

K1:CAL-MEAS_{CURRENT, LATEST}

We accepted the SDFs reported on klog34391.

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 is expected to be accepted.

Operator: Shingo Hido, Dan Chen

Update Time: 2025/06/27 15:07:49

Update Time: 2025/06/27 15:08:24

Update Time: 2025/06/27 15:09:03

Update Time: 2025/06/27 15:09:35

Abstract

In klog#34162, ~5% difference around 100Hz between online and low-latency h(t) was pointed out.
So I checked validity of this fact and it seems to come from the incompleteness of online calibration.
This fact suggests that actual sensitivity is slightly better than one shown in control room by using online h(t).
 

Details

Major and known factors of incompleteness of online calibration are 1) digital AAs for 65kHz->32kHz and 32kHz->16kHz 2) compensation of whitening filter on DCPD preamp board and 3) timing mismatch between error signal and feedback signal. Response of these effects are shown in Fig.1 and Fig.2 (zoom up around 0dB).

Because 1) is a super-Nyquist effect (zero/pole above Nyquist frequency), they cannot be compensated by using foton filters which are IIR filters based on bilinear transform. So this effect can be compensated only on low-latency and/or offline h(t). Only phase delay is compensated also on online h(t) as an approximant as time delay.

2) comes from the mismatch between the best estimation of circuit response of DCPD preamp whitening and digital dewhitening on FM10 of K1:OMC-TRANS_DC_{A,B}. By updating digital dewhitening filters, accuracy of online h(t) can be improved. But this update makes a change of open loop gain around UGF. So the DARM servo filter is also update at the same time. Because phase around 7-70Hz is also changed, we should check that there is no problem also on GR and RF lock.

3) comes from the accuracy of timing (phase) adjustment between error signal and feedback signals. In low-latency calibration, arbitrary time delay is compensated. On the other hand on online calibration, time delay compensation is done as a integer multiple of the sampling rate. The best estimation of timing mismatch between two signals is ~7.8 samples in 16kHz (=476us). Current timing compensation of online h(t) is 7 samples. So there is 0.8 samples mismatch. Compensation can be update as 8 sample and mismatch can be reduced 0.2 samples even online calibration. For doing it, model or foton filter updates are required.

As shown in Fig.2, total bias coming from these effect is ~0.45dB (=~5%) which is consistent with a mismatch between low-latency and online. This fact suggest low-latency h(t) is more close to the actual sensitivity and actual sensitivity is slightly better than one shown in control room.

Fig.3 and Fig.4 (just zoom up around 0dB) show the possible accuracy of online h(t) when all compensations mentioned above will be adopted. Accuracy of online h(t) can be improved from blue (current) to orange (best effort). By the way, bad accuracy above 1kHz comes from digital AA effect. In KAGRA, OMC model is running as 32kHz model. For this reason, two digital AAs which cannot be compensated on online h(t) contaminates accuracy. If we can change OMC model as 16kHz, additional improvement (orange -> black) will be available. Of course, they can be compensated in low-latency h(t). So it's not a problem on search groups.

[mTakahashi, Miyoki]

The aater level of the chiller for the beam dumpers sert in the PSL room was confirmed to be full. So no problem.

I cleared the filter bank history of 1:VIS-ETMX_IP_ISC2LVDT_L filter bank.

I accepted SDF of the following channels.

k1omc model (fig1):

K1:OMC-QPDV{1,2}_{PIT,YAW}:

These modification is related to the low-pass filter implementation reported in klog34386.

[Aso, Ushiba]

Abstract:

We implemented low-pass filter for OMC in-vac QPD to check if they can be used for OMC ASC or not.
To avoid conflict with OMC initial alignment with INITIAL_ALIGNMENT guardian, the filters are managed by OMC_LSC guardian.

Detail:

Though in-vac OMC QPD signals varies a lot, long-term trend seems stable.
Figure 1 shows the minutes trend data of OMC in-vac QPDs, and the average value seems almost constant.
They might be used for OMC ASC during the OBSERVATION, so we set low-pass filter at K1:OMC-QPDV{1,2}_{PIT,YAW} filter banks to see only slow trend of the signals.
Figure 2 and 3 show the filters we set at the filter banks (we set the same filters at the other filter banks).
Figure 4 shows the QPD signals after low-pass filter engagement and it looks fine because no large glitches.

After checking the filters seem good, I implemented the function in the OMC_LSC guardian to turn on them for OBSERVATION and turn off at DOWN state to avoid conflict with OMC initial alignment with INITIAL_ALIGNMENT guardian.
Figure 5 (DOWN state) and 6 (OMC_LSC_LOCKED_FOR_10W state) show the guardian script I modified.

We will monitor the signals during the observing run this weekends.

The Planetary Imager for the ETMX showed the strange images (see the attached image). This is the same issue of klog33355.
To fixt the issue, I pushed the 'recover' button on the medm. After rebooting, the screen in the control came back to the normal situation.

The previous work is klog34301.

• ITMY
  • 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 measured Spectrum and OLTFs after the Pcal-X calibration work.

MICH has diff by ~1.4dB from the ref.
PRCL has diff by 0.6dB from the ref. (Almost same as the previus measurement on 6/19 = klog34296)

The title should be "Spectrum and OLTF measurement on June 26 after the site work"!!!

I took the TCam photos for four mirrors at 8:42 ~ 8:50 this morning. I will check the images.

I tweaked beam spot on ITMY by changing drivealign matrix but no significant change can be observed even waiting for more than 1 hour.
So, I reverted ITMY drive align matrix.

Abstract:

I tried to reduce the Type-A suspension kick when lockloss happens.
Since it seems difficult to set proper ISC WD threshould and the speed of suspension kick is not to fast, I modified ASC_LOCK guardian to turn off ASC feedback to MN stage as early as possible when lockloss happens.

Detail:

To set proper threshould for ISC WD by using ASC signals, I first checked the signals of K1:VIS-ITMY_ISCWD_WD_AC_Y_RMSMON during the OBSERVATION state and when lockloss happened.
Figure 1 shows the largest signals of the trigger channel during the silent run yesterday.
Figure 2 shows the smallest signals of the trigger channel when the lockloss happened.
Though the signals in fig2 is slighty larger than the signals in fig1, it doesn't seem good way to set the threshould between them because the difference is small.
So, I gave up to set ISC WD threshould.

Then, I checked the ASC feedback signals when lockloss happened (fig3).
Since feedback signal change is about 1 cnt even after 300ms (about 5 smples with 16Hz) after lockloss, it would be enough slow to stop feedback by guardians.
So, I modified the DOWN state of the ASC_LOCK guardian as shown in fig4 and fig5.

Since the guardian doesn't change OBSERVATION state, this modification oesn't affect to the IFO during OBSERVATION.

I accepted the following SDF changes which were made by Pcal-X calibration reported klog34375.

CALEX

K1:CAL-PCAL_EX_{1,2}_PD_BG_TX_V_SET
K1:CAL-PCAL_EX_1_PD_BG_RX_V_SET
K1:CAL-PCAL_EX_{1,2}_OE_{T,R}_SET
K1:CAL-PCAL_EX_{1,2}_RX_V_R_SET
K1:CAL-PCAL_EX_WSK_PER_{TX1,TX2,RX}_SET
K1:CAL-PCAL_EX_2_INJ_V_GAIN
K1:CAL-PCAL_EX_CURRENT_TIME

Time stamp

• 09:17 Entered the central area
• 09:18 Exited the central area
• 09:35 Entered the X-end
• 13:02 Measurement completed
• 13:17 Exited the X-end
• 13:39 Entered the central area
• 13:48 Exited the central area
• 13:52 Exited the tunnel