> Is it possible that a same thing is happening in IX (IY and EX)?

I guess YES in IX, however, No in IY and EX.

Note that following is EY situation not IX.

Current (wrong) channel assignment:
- EY-No.1 #Ch3 = K1:CRY-TEMPERATURE_EY_4K_COOLING_BAR_REF4
- EY-No.1 #Ch6 = K1:CRY-TEMPERATURE_EY_4K_COOLING_BAR_REF2

Correct channel assignment:
- EY-No.1 #Ch3 = K1:CRY-TEMPERATURE_EY_4K_COOLING_BAR_REF2
- EY-No.1 #Ch6 = K1:CRY-TEMPERATURE_EY_4K_COOLING_BAR_REF4

Is it possible that a same thing is happening in IX (IY and EX)?

I found a correlation between the change in VIS-ITMX_MN_DAMP_L_INMON that was pointed out by Ushiba-kun and the sudden temperature reduction of  IX_4K_REF4_HEAD and IX_4K_COOLING_BAR_REF2.

So, some heat shock caused this change.

In addition, the cryocooler, which was turned off today, seemed to be connected with the REF4 cooling bar, not REF2. So, should we change the cryocooler that should be turned off?

Attached figure shows the first one hour spectrogram of the photosensor signals.
It seems to become a bit stiffer.
We need to keep monitoring.

I injected excitatio signals between 0.1Hz and 1Hz (fig1).
After excitation, we can clearly see the oscillation in photosensor yaw signals (fig2).

I increased the current for ITMX IM heater to 0.2A (fig1).

Ushiba, Tanaka

We continued the trial of releasing ITMX. We tried to confirm that EQ around MN or IM touches or not by measuring the response from one coil to the related sensor, Yaw photosensor in the horizontal coil case, PIT (or Roll) photosensor in the MN vetrial coil case, and TM PIT oplev (or MN Roll oplev) in the IM vetrial coil case when we excite the stage at 0.125 Hz with one coil. Since each EQ is near each coil, if any EQ is touched, the response from the coil near the touched EQ should be smaller than the others from the other coils near the untouced ones.

We performed the measurement for ITMX and for ITMY, and compared them.

Fig. 1 and Fig.2 show the results with each horizontal coil at MN and IM stages, respectively. Fig.3 and Fig.4 show the results with each vertical coil at MN and IM stages. Also, the following table is the summary of the responce values.

As for horizontal coils, IX responses are 10 dB lower than IY responses but each response of IX are almost the same. This may indicate that the EQs in horizontal dirction do not touch anywhere. On the other hand, as for vertical coil, IX responses are more than 20 dB lower than IY responses. Also, PIT responces by V1 or V3 seems to be lower than Roll responce by V2. However, PIT response by V1 seems to be almost the same the one by V3. So something distutbs PIT motion rather than Roll motion.

The temperature changes at EY_4K_REF4_4K_HEAD from 50K to 90K after turning off the REF4 cryocoolers took 5 days to reach.

EY_4K_COOLING_BAR_REF2 also shows the same tendency. So, the same tendency will be expected in the IX  case. In IX, the heater at IX IM will be used. So more rapid warming up is expected?

Seemingly interesting. Please softly touch the duct in this area later.

[Kimura and Yasui]

 On May 16, ion pumps #5 and #7 were stopped and the TMPs were started in preparation for warming up the ITMX.
The #29 ion pump next to the IXV was also stopped.
After the TMPs were started, the P-54  cryo-cooler for cooling the ITMX was stopped.
 These operations were carried out between 14:00 and 15:10.

Date: 2025/05/16

Member: Misato Onishi, Keisuke Sakanoue, Dan Chen

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.

[YamaT-san, Ikeda]
We replaced the drive in Pod#1 Disk#2 of E18 (Fig. 3) with a replacement HDD obtained from Cross Head (Fig. 1) (the drive with the red LED shown in Fig. 2).
After the replacement, the drive entered standby status as a Pool Spare (Fig. 4), and we confirmed that the LED changed to green (Figs. 5 & 6).
Additionally, the log time was set to 2006, so we corrected the system time.

After the replacement, several read errors occurred (Fig. 7), and we are planning to replace it again once additional HDDs arrive.
[Documentation]
T2516683 E18 Maintenance Manual
 

If I had to say, 'K1:PEM-MIC_PSL_TABLE_PSL3_Z_OUT_DQ', is similar?

But this microphone doesn't have enough coherence with DARM or REFL_PDAs

I checked the PEM sensors (from PSL to BS) spectrum for the same time with 64s FFTs.

No significant structures at 116 Hz are found.

If MN(IM) and/or MNR(IMR) were supposed to drift horizontally, is it better to drive MN horizontally, not pitch and yaw to locate MN at the center of the inner space of MNR?

Under the condition where MN(IM) and MNR(IMR) are attached, the pitch and yaw actuation just changes the contacting points.

I offloaded the F0 GAS with the FR.

I offloaded the F0 and F1 GAS filters with the FRs.

A front-end computer for PRM suddenly hung up around 15:05 JST.
It seems a same issue as K1ALS0 on May. 4th (see also klog#33675).
Finally, K1PRM was recovered by power cycles from BMC interface.

-----
Because there seemed to be no concern about secondary disaster and ITMX measurements were running, I recovered PRM after finishing ITMX measurements around 17:06 JST (see also Fig.1). For restarting PRM front-end, I requested SAFE to all suspensions connected to the Dolphin network. Because there were lots of SDF differences and it's difficult to clear all of them, I rebooted PRM only with taking snapshot of SDF difference windows. Fortunately there was no trouble and I didn't need to use snapshots.

With Hiroshi Takaba

We conducted the integrating sphere calibration for Pcal-Y.
The results are attached. (PDF file)

There were no unexpected issues during the measurement.
The related EPICS parameters were updated.
(See the attached graph fig_001.png for updated results.)

Time: 2025/05/15 16:50:34

Additionally, I performed several measurements to identify the rubbing point in the suspension.

Test mass TFs

Excited a TM coil at 10Hz and measured the TF to TM OpLev Pitch.

MN to MN TFs at 0.1Hz

Re-measurement of the MN to MN TFs at 0.1Hz to avoid the 0.3Hz Yaw resonance.

I could not finish the measurements for the IM TFs. 

Summary

By applying a large negative offset in MN Pitch, the MN Yaw TF became much better. However, the cross couplings are still very large. Also, the TM OpLev is completely out of range in this state. So, even if we can release the IX suspension, we cannot recover the IFO alignment. Time for warm up?

Pitch adjustment

I tried to measure the MN OpLev TFs with a large offset applied to variou DoFs.
In most cases, the TFs were pretty bad. However, when -10000cnts (equivalent to 30000cnts at the coil output) was applied to Pitch, the TF became much better.

Blue curve is the healthy TF in room temperature.
Brown is when no offset is applied to MN.
Red is when P=-10000 is applied.

Note that the shadow sensor efficiency has changed by the cooling. From the difference in the free mass region (10Hz or more), the sensor efficency has increased by about 10dB when cooled.

After finding this, I tried to further tilt the MN by using the moving mass in the same direction. However, the TF did not change any more.

Then I reduced the Pitch offset to -5000 and used the moving mass to keep the pitch angle. This allowed me to put some offset also in Roll.
Below is when P=-5000 and R=-2000 are applied.

The brown curve in this figure is the TF with P=-10000. 

I found that Roll does not change the TF so much. In fact, if I apply a positive offset to Roll, the 0.33Hz peak shifts to higher frequency. So Roll adjustment seem to be not effective.

While it may be possible to find a combination of offsets and moving mass positions, the TM OpLev is completely out of range in such a configuration (at least it is so when P=-10000 is applied).
Then we cannot recover the IFO alignment. Therefore, warm up seems unavoidble in anyway.

For your reference,  I attached other TFs with various MN offsets (applied to the maximum value before saturating the coils).

Additional Test of HIB Card

Overview
We investigated the results when using different IO chassis.
This time, the environment used was slightly different.

PC
 V4
IO Chassis
 S1301984
Cable
 Optical 10m? (Orange)

Results
 There were no differences caused by the Host card.

Host cards used

120018
120016
QS13491142
QS13491113
QS13491022
QS13491183
HIB35
QS13491182 (Add)

Target cards tested and results

197224: Only CR3 lights up green; CR2 is off. Fig2 (normally both are on. Fig1)
Half of the PCIe Express Slot was unusable.
On the A0 side, the card was not recognized. On the A2 side, the card was recognized.

197219, 201050: The LEDs CR5 and CR7 lit up red, and the card was not recognized. Fig3

Conclusion
All cards except 197224, 197219, and 201050 could connect with any of the Host cards.
However, there were a few cases where connection issues occurred when plugging the cable into the Target card connector.
All such issues were resolved by reinserting the cable.