Results of the partial pressure measurement at 7:43 on Jan. 11 are as follows; 

The partial pressure of the residual gas components were recovered to the level before the interlock device operated and the gate valves closed.

[Kimura and Yasui]

 BS CC-10 pressure reached 7.5 x 10^-6 (Pa) at 16:10. 

The threshold of the CC-10 contact output was then set to (7.5 + 0.5) x 10^-6 (Pa) of 8.0 x 10^-6 (Pa). 

After setting, the interlock device was enabled.

I changed the ETMX BF yaw setpoint to offload the MNY actuator outputs.
The value was changed from -1700 to 200.

ETMX OpLev SUM is now about 100 cnts while it was ~10000 cnts before cooling, so I started to investigation.
Figure 1 shows the MN OpLev SUM when changing the MN Optic align values at PAY_FLOAT state.
When MN Optic align values are -1200 cnts from the aligned position, MN OpLev SUM is more than 9000, which implies that MN OpLev beam is clipped somewhere.

Since the cooling would change the relative angle between TM and MN, this phenomena can happen even if we kept the good alignment of ETMX.
What we can do depends on the situation:
1. If the clipping happens on the BS of the detection port, we can recover it by realigning the optics on the reciever side.
2. If the clipping happens inside the cryostat, we need to move injection beam to recover the clipping.

Anyway, ETMX MN OpLev damping performance getting worse and it is dificult to lock the interferometer stably in this condition, so we need to fix the probem.

Uchiyama, Tanaka

Ushiba-san asked us to install an oscillation stopper (発振止め) in Fig.1 between the VMON port on TM HPCD and the whitening charsis and to turn on the 3-stage whitening filters.

We installed it (fig.2) and turned on them . Also, we engaged the dewhitening filters in the TM_COILDRV_VMON filterbank (fig.3).

Uchiyama, Tanaka

We tried to replace the TM HPCD to the one for beacon summing (s2315283) at EX.

We requested the ETMX guardian to go to the SAFE state before the replacement. We turned off the old coil driver after ETMX reached the SAFE state. Then, we replaced the coil driver to the one for beacon.

After that, we restored ETMX to the PAY_FLOAT state, and we measured the TFs from ETMX_TM_COILOUTF_H{1,2}_IN2 to ETMX_TM_WIT_P and the TFs from ETMX_TM_COILOUTF_H{3,4}_IN2 to ETMX_TM_WIT_Y at 10 Hz. Fig.1,2,3,and 4 show the results of H1, H2, H3, and H4, respectively.

In the old coil driver setup, the summing adaptor has 2.7dB loss at the input of the driver. So we compensated it with the gain in FM10 of COILOUTF. On the other hand, in the new coil driver setup, there were no loss according to the TF measurement results by the AEL group (JGWdoc). Therefore, the gain of the TF (brown) when we used the new driver and we turned off FM10 of COILOUTF should be the same as the previous results (blue). In this sense, H2 result seem to be fine but the others seem to be ~6dB lower than the ones in the previous setup.

We suspected that the previous health check was performed last June, that is, the payloads were not cooled and the gain became lower by cooling. So we replaced the new driver to the old one. And we measured the TF. The red line in the figures are shown the results. The reds seem to be the same as (or slightly larger than) the blues. Therefore, the cooling seems to be not the cause of -6dB.

We left the old coil driver in the ETMX rack and we brought back the new one. I asked AEL group to investigate the cause.

I took the TCam photos for four mirrors at 14:42~14:52 after the initial alignment. I diagnosed the analysis results and it's unnecessary to update the reference values.
The mirror appearances were same as usual and healthy.

I edited the medm screen for the initial alignment, to remove the misunderstanding.

[Yokozawa, Yuzurihara]
We performed the full initial alignment (Xarm, Yarm, OMC and PRMI) in 14:08~14:40. During Yarm alignment, I changed the setpoint of BS in pitch: 10.9 -> 12.9.

[kimura and Yasu]

 We turned off two TMPs and two dry-pumps at 14:50.

[Kimura and Yasui] 

GVbsx and GVbsy were opened in the following steps.

2Step 1: 

 13:45 Disabled the enable/disable switch in the GVbsx and GVbsy interlock device.

Step 2

13:48 Opened GVbsy and closed the GVs of the TMP.
BS-CC-10 pressure was 1.4 x 10^-5 Pa.

Step 3

13:50 Opened GVbsx and closed the GVs of the TMP.
BS-CC-10 pressure was 1.4 x 10^-5 Pa.

Results of the partial pressure measurement are as follows;

Because TMPs will be off, I recovered the target temp for the precision cooler from 19 to 20 and turned off two Sunrise heaters around 14:00.

I found several filter banks (ITMX_NBDAMP_V1, ITMY_NBDAMP_R1, and ITMY_MNOLDAMP_P) not loaded after modifying the filter parameters.
This time, I loaded all of them because these changes are just gains, notch frequencies, and filter name, and I could confirm new filter seems fine.
However, if it is a complex modification, it would take time to confirm loading new filters are good or not.
So, please be careful not to forget to load the filter banks after changing the filters.

I noticed ITMX NBDAMP V1 filter was designed but not loaded, so I load filter bank and measure the OLTF.
Figure 1 shows the result, and there seems no significant difference between reference (before load) and current one.
So, the lop seems fine.

Conclusion

Details

Introduction

1. Relationship between the tightening levels of set screws and the mirror’s spectrum

2. Relationship between number and type of clamps and the mirror’s spectrum

3. Relationship between clamps position and the mirror’s spectrum

4. Relationship between tapping locations and the mirror’s spectrum

Next

I tried to reproduced a change in the pressure value (KGRVAC:CCG_BSY_01:VAL:PRESS) after it became larger than the threshold of guardian notification from the guardian log (See Fig.1).
Log is recorded only when pressure value was larger than the threshold of guardian notification and pressure value is changed, so sampling interval is not a constant value.

Guardian threshold was set as 8.0e-6Pa in klog#32116. The first log appears at 10:55:35.885674 JST. That is, the time when the pressure value first reached the Guardian threshold. Interlock threshold which was shown as red line in Fig.1 was set as 9.4e-6Pa in klog#32173. Readout value first reached interlock threshold at 10:57:52.902407 JST. It took 147s to increase from 8.0e-6Pa (Guardina threshold) to 9.4e-6Pa (interlock threshold). Fig.2 is a same plot with longer duration. Attached text file is an original guardian logs used to make these plots.
 

Owing to two TMP operations near BS, the vacuum level at the MICH area seemed to decrease and reached the equilibrium pressure? This means that more TMPs operation will result in the lower pressure.

The pressure difference at BS before and after closing GVs is just 2 times. 

So can we open GVs? or shall we temporally operate all TMPs in the MICH area and wait to reach the same vacuum level?

To solve the coupling issue in klog, we started to perform the sensor balancing and diagonalization for ITMY sensors.

ITMY photosensor balancing was performed with the script. Fig.1 and Fig.2 show the results in the horizontal and vertical sensors, respectively. They seem to be fine.

After that we performed the ITMY MN sensor diagonalization with the script. Fig.3,4,5,6,7, and 8 show the diagonalization results. They seem to be fine except for the coupling from Y to other DoFs in Fig,8.

I found that the values of the coupling ratios at the Y resonace frequency, 3.11 Hz which were picked up by the script (the last column in the left panel of fig.9) seem to differ from the measument results themselves (the last column in the right panel of fig.9) as for only Y. I tried to input the actual measurement results but the situation was not changed. We need more investigation.

Because Kimura-san started two TMPs/Dry pumps near BS(Kimura-san? will report) for the pumping in the MICH area, I,

• turned off two Sunrise heaters near SR2+X side and PR3-Y side,
• changed the target temp of the precision cooler near SR2 from 20.00 to 19.00.

to adjust the temperature around BS at around 18:00.

I implemented modal damping for ITMX GAS filters with the same manner as ETMY (klog31916) and ETMX (klog31933).
Figure 1 shows the spectra of LVDTs and OpLevs with (red) and without (blue) modal damping.
Spectra of F3 GAS filters became worse when engaging modal damping but it is not due to modal damping but the ADC glitches, so it doesn't matter.
Other than F3, the spectra became better, so modal damping seems to work well.

I implemented it into te guardian, so M1 modal damping is automatically turned on when the suspension is LOCK_ACQUISITION state.

[TSYamamoto, Yuzurihara]

TS Yamamoto-san and I have worked on developing the line monitor for one-day data in which the LSC_LOCK guardian is in the state more than PRFPMI_RF_LOCKED. The related klog is klog#31884.
Today, I implemented the automation of the process. The process of analyzing the one-day data runs on k1det1 and will start every 9:25. In the future, it's better to move the running place to the detchar cluster and manage the jobs by using HTCondor. (It's also the same for the Gauch.)
You can access the latest result from the link or the summary page --> DetChar --> Line Monitor.
The result of 2024/12/30 can be seen in the link. The line fit results can be seen in the link.

(Work on 1/8)
We found that these oscillations grow over the course of several hours, so we turned on these two control loops (Y3, Y4).
Additionally, we modified the Guardian to enable turning them ON/OFF.