We generated the ground vibration noise by continuously tapping the PC table outside of the OMC booth.
We need more investigations, but just for memo.
We generated the ground vibration noise by continuously tapping the PC table outside of the OMC booth.
We need more investigations, but just for memo.
See also
https://klog.icrr.u-tokyo.ac.jp/osl/?r=18434
https://klog.icrr.u-tokyo.ac.jp/osl/?r=18495
https://klog.icrr.u-tokyo.ac.jp/osl/?r=27364
https://klog.icrr.u-tokyo.ac.jp/osl/?r=28985
https://klog.icrr.u-tokyo.ac.jp/osl/?r=28999
[YokozaWashimi]
We located a 3-axial accelerometer below the OMC chamber, near a seismometer.
Used channel names are
K1:PEM-PORTABLE_OMC_RACK_OMC1_ADC0_DSUB13_OUT_DQ
K1:PEM-PORTABLE_OMC_RACK_OMC1_ADC0_DSUB14_OUT_DQ
K1:PEM-PORTABLE_OMC_RACK_OMC1_ADC0_DSUB15_OUT_DQ
and the signal unit is calibrated to m/s2.
Plots attached here are reference data (21 JST,) no one inside the mine.
The shape and value of the Geophone's ASD is similar to the seismometers at 40-130 Hz and to the accelerometers at 50-130, and 160-250 Hz.
From these results, the in-vac table may not reduce the ground vibration.
The peak around 30 Hz is only found in the geophone signal and is larger than the seismometer and accelerometer.
Something inside the vacuum makes amplification?
For this peak frequency, the coherence with SEIS Z is very large.
We generated the ground vibration noise by continuously tapping the PC table outside of the OMC booth.
We need more investigations, but just for memo.
Ushiba, Tanaka
### Abstract
We succeeded LSC lock of IMC with IO guardian. The transmitted beam from MCE seems not to hit trans PD. So we aligned IMC to minimize the REFL power and to hit on the camera position reported in klog28978 manually. We found when the error signals of REFL WFS are 0, the IMC alignment got bad. So we need more investigation whether the beam clip or not on the REFLWFS path.
### What we did
Today I checked how our portable shaker could generate vibration using the 3-axial accelerometer, near the MCF chamber.
The output signal was the same as in the last week's work.
Because the shaker moves vertically, the Z signal was the largest, but an excess of around 70 Hs was found in X&Y.
Even though the shaker was OFF (blue), the peak at 60 Hz and 58.8 Hz was much larger than last week. Due to vacuum evacuation?
After this work, I moved this accelerometer to the OMC area.
I changed the setpoints of the GAS filters for the height adjustment.
Before | After | |
F0 | 4422 | 4444 |
F1 | -1970 | -1406 |
F2 | -1460 | -1311 |
F3 | 554 | 710 |
Photo of the inside. (white tapes are temporary attached)
[Takahashi, Ushiba]
We adjusted the mirror height with respect to the target marker on chamber flange center.
Fortunately, ITMX height can be easily recovered by changing the GAS setpoint to the ones just before vacuum evacuation before O4.
Figure 1 and 2 show the photos around magnets with laser leveler, which was set at target mirror height.
Note:
ITMX is slightly tilted in roll, so laser hits slightly high position in fig1 and low in fig2.
I changed the setpoints of the GAS filters for the height adjustment.
Before | After | |
F0 | 4422 | 4444 |
F1 | -1970 | -1406 |
F2 | -1460 | -1311 |
F3 | 554 | 710 |
When we adjusted PR3 height(klog:28800), we used reference point which was copied from target seal at chamber +X+Y side. (pic.1)
I removed the half-wave plate (HWP) that changed the polarization and was located between the shutter and the periscope at the very end of the PLS table (before Fig.1, after Fig.2).
Now the polarization is back to S.
I left the HWP on the PSL table just the side of the shutter. I saw a beam to RFAM and was careful not to block it by the HWP.
By the way, I noticed that the aperture of the HWP was only .5 inch. The beam diameter looked more than 1cm on the sensor card. Was there no clipping?
> I noticed that the aparture of the HWP was only .5 inch. Beam diameter looked more than 1cm on the sensor card. Was there no clipping?
Some of us have already known it (for example 28776). We have been worried about this, and so sometimes this point was discussed in some morning meetings. In any case, please prepare the better HWP for the next case.
> I noticed that the aparture of the HWP was only .5 inch. Beam diameter looked more than 1cm on the sensor card. Was there no clipping?
Some of us have already known it (for example 28776). We have been worried about this, and so sometimes this point was discussed in some morning meetings. In any case, please prepare the better HWP for the next case.
I attached a graph showing the time change of beam position analysis result.
Since the 25th, there are occasional changes of 1 or 2 mm, which are thought to be due to changes in scattered light caused by slight changes in the orientation and position of the mirror.
Overall, there appears to be no significant shift changes on the Pcal beam position.
Date: 2024/3/29
I checked the alignment change from the last alignment adjustment on 25th.
This time, I requested "ISOLATED" state to the suspension for taking the pictures.
Then I compared a picture on 3/25 taken just after the alignment adjustment, and a picture today.
I can not see any change.
Before this, I confirmed that the ETM position on the Tcam pictures did not change.
[Ikeda, Washimi, Takahashi]
We replaced the P2 feedthrough flange.
Old | New | Inductance | |
1:PI LV1 1-6 2-7 3-8 4-9 5-G |
317Ω 248Ω 146Ω OL 5.3Ω |
317Ω 248Ω 146Ω OL OL | 35.38mH 52.41mH 61.53mH
|
2:SF LV 1-6 2-7 3-8 4-9 5,6-G |
198Ω 78.6Ω 111Ω OL 3,6Ω |
198Ω 78.7Ω 111Ω OL 0,0.4Ω | 39.21mH 10.12mH 68.95mH
|
3:TM H2 1-6 2-7 3-8 4-9 5-G |
OL 18.5Ω OL OL 1.4Ω |
OL 18.6Ω OL OL OL |
8.631mH
|
4:F0 LV 1-6 2-7 3-8 4-9 5-G |
196Ω 77.3Ω 114Ω OL 1.7Ω |
196Ω 77.1Ω 114Ω OL 0.5Ω | 42.59mH 10.56mH 73.79mH
|
5:PI FR 1-6 2-7 3-8 4-9 |
5.0Ω 4.7Ω 3.2Ω 3.3Ω |
4.8Ω 4.8Ω 3.2Ω 3.3Ω |
|
6:IM H1 1-6 2-7 3-8 4-9 5-G |
5.8MΩ 17.8Ω OL OL 2.3Ω |
5.8MΩ 17.7Ω OL OL 4.3Ω | 0.531V(6+) 8.357mH 1.70V(3+)
|
7:TM H3 1-6 2-7 3-8 4-9 5-G |
OL 18.5Ω OL OL 10.6Ω |
OL 18.5Ω OL OL OL |
8.662mH
|
8:PI SM 1-6 2-7 3-8 4-9 |
6.3Ω 6.9Ω 6.1Ω 5.1Ω |
6.6Ω 6.8Ω 6.1Ω 5.2Ω |
|
The Pin-6 in P2-2(SF LV) was grounded. There were not any other cross-connections. Though the Pin-5 in P2-1, P2-3, and P2-7 were grounded, they were floated after the flange replacement. It may be due to the condition of the aluminum foil covering the Dsub connectors.
Photo of the inside. (white tapes are temporary attached)
[Ikeda, Washimi, Takahashi]
We applied new cabling to the primary coils for the BF damper. The lead wires were re-cabled on the side of the coil bobbin with the PEEK tie-anchor or the PEEK plate. Additionally, the lead wires were fixed on the coil bobbins with an adhesive (TRA-BOND 2116).
Since about 2 weeks ago, I could not access the Y-end water fluid meter via the network.
(The cause is not understood, but its web server sometimes hangs up.)
Today I went to the Y-end and checked it. The measurement was continued.
So I saved the data on the CF memory and rebooted the Y-end water fluid meter, manually.
After that, it worked well and the data was not lost.
Sorry, "DAC noise" was typo of "ADC noise".
Washimi, Akutsu following 28985.
For the further inspection of the invac OMC geophone that had a strange lower signal boundary (see 28985), the analog output of the geophone distributor was inspected, and we confirmed that the strange lower bound was already there. Is it of specification of this geophone? or some mulfunction?? In any case, it might be nice to open OMM-OMC chamber soon.
Looked around the NAB at IYA, and touched it. I did not find particular issues on the NAB so far, though I inspected it from one side of the IYA flange (though accessible only from the one side).
This should is the last of the NABs that should be checked in the Noto earthquake recovery.
Looked around the NAB at EYA, and touched it. I did not find particular issues on the NAB so far, though I inspected it from one side of the EYA flange.
Washimi-kun
Thank you for your replies.
I have several comments and additional questions.
1. You mentioned injection signals have high pass at 60 Hz, and it means the injected vibration is no frequency response (white noise in frequency region above 60 Hz). However, excess noise around 60 Hz is much smaller than those around 80 Hz. Does it imply vibration inside the chamber around 80 Hz is enhanced somehow from the ground vibration?
2.You said sensor noise and DAC noise are about 2e-6 but I cannot understand what the DAC noise level is. Does it mean DAC noise (~1e-6V/rtHz) is equivalent to 2e-6 m/s^2/rtHz?
3. What I would like to know is not the injected vibration is large enough with respect to the ground motion but the vibration on the optical table is enhanced from the tje injected vibration. If so, the ground vibration is somehow enhanced by the stack (or chamber) and it is so problematic. So, I would like to know the relations between injected signal and vibration on the stack.