Reports of 26700
CAL (XPcal)
dan.chen - 6:59 Friday 29 March 2024 (29005) Print this report
Comment to Alignment recovery of Pcal-X (28796)

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.

  • TCam_ETMX_00001_2024_0325_145559.png
  • TCam_ETMX_00001_2024_0329_052158.png

I can not see any change.
Before this, I confirmed that the ETM position on the Tcam pictures did not change.

Images attached to this comment
VIS (BS)
ryutaro.takahashi - 23:53 Thursday 28 March 2024 (29004) Print this report
Replacement of feedthrough flange

[Ikeda, Washimi, Takahashi]

We replaced the P2 feedthrough flange.

  1. Checked the resistance between all pins in each Dsub connecter on the present flange (leaked previously) without the flip cables.
  2. Removed the present flange.
  3. Tagged a number and name to all Dsub connectors on the new flange.
  4. Connected the in-vacuum cables to the Dsub connectors.
  5. Closed the flange with two screws temporally.
  6. Checked the resistance between all pins in each Dsub connecter on the new flange without the flip cables.
  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.

Images attached to this report
VIS (EY)
ryutaro.takahashi - 21:03 Thursday 28 March 2024 (29003) Print this report
Re-cabling of BF damper

[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).

Images attached to this report
PEM (EY)
tatsuki.washimi - 18:49 Thursday 28 March 2024 (29002) Print this report
Maintenance of the Y-end water fluid meter

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.

Images attached to this report
PEM (Center)
tatsuki.washimi - 18:19 Thursday 28 March 2024 (29001) Print this report
Comment to MCF/MCE shaking/tapping test (28943)

Sorry, "DAC noise" was typo of "ADC noise".

VAC (MCF)
takashi.uchiyama - 18:06 Thursday 28 March 2024 (29000) Print this report
Pumping down of IMC has started
2024/03/28

Uchiyama

I started pumping down of IMC from 9:41.
Finally, TMP was in the normal state at 17:19.
MIF (General)
tomotada.akutsu - 16:29 Thursday 28 March 2024 (28999) Print this report
Invac OMC geophone signal sanity check

Washimi, Akutsu following 28985.

Summary

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.

Details

  • Setup: [Distributor] - [R. Takahashi-san's Dsub-LEMO convertor (Figs. 1 and 2)] - [Washimi-san's portable oscilloscope driven by a battery]
  • Measurements: tapped (rather touched) a sticking out part (mass spectrometer) as like yesterday, then immediately the oscilloscope showed the signal was strangely bounded in the lower region (Fig. 3). From this figure, you may be able to estimate how large the signal is.

Note

  • We used an battery-driven oscilloscope. Please be careful not to use "usual" oscilloscope that might have its signal GND connected to power supply's GND. KAGRA's analog signals are differential types, and if you connect the negative side of the differential pair signals, the whole system might be, in the worst case, broken. Never do it.
  • In any case, the coupling path from the part touched to the geophone is unknown. This has to be known for the better sensitvity of KAGRA. We need to open the OMM-OMC chambers soon to check the coupling.
  • On the other hand, even when the geophone responded, OSTM's OSEMs are not so much (Fig. 4). In this figure, the lower one shows the invac geophone, and the upper four are of these OSEMs. The signal was made by my light tapping on the floor near this desk. Hmmm... is this due to difference of the frequency range?? I did not take time for this point today so much, so further investigation should be done later by someone.
Images attached to this report
AOS (Baffles & Beam dumps)
tomotada.akutsu - 11:21 Thursday 28 March 2024 (28998) Print this report
NAB check at IYA

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.

Images attached to this report
AOS (Baffles & Beam dumps)
tomotada.akutsu - 11:20 Thursday 28 March 2024 (28997) Print this report
NAB check at EYA

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.

Images attached to this report
DetChar (General)
nami.uchikata - 9:11 Thursday 28 March 2024 (28986) Print this report
O4a summary page
I have made dedicated summary page for O4a of KAGRA.
Currently, uploaded to the ICRR cluster and will be moved to the Kamioka cluster.
https://www.icrr.u-tokyo.ac.jp/~uchikata/Detchar/O4aSumm/gps/1368975618-1371337218/
PEM (Center)
takafumi.ushiba - 0:48 Thursday 28 March 2024 (28996) Print this report
Comment to MCF/MCE shaking/tapping test (28943)

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.  

PEM (Center)
tatsuki.washimi - 18:53 Wednesday 27 March 2024 (28995) Print this report
Comment to MCF/MCE shaking/tapping test (28943)

Answers for Ushiba-san:

  1. For the shaker, the Injected signal (digital) was 20-5000Hz white noise. However, due to the shaker's specs, it was high-pass at ~60Hz. 
  2. I checked the coherence in xml files, but somehow it was not recorded. (Only in the template file, coherence was recorded. that's a mystery). I will try it from frame files.
  3. The sensor and DAC noise level is about 2e-6 m/s2/√Hz for the ACC. So about over 30 Hz is actual vibration.
  4. The injected vibration should be much larger than the vibration on the table because the shaking vibration was very large and I could feel it by hand.

 

VIS (IY)
ryutaro.takahashi - 17:50 Wednesday 27 March 2024 (28993) Print this report
Re-cabling of BF damper

[Ikeda, Washimi, Takahashi]

We applied new cabling to the primary coils for the BF damper. The lead wires for V2, V3, and H3 coils were re-cabled on the side of the coil bobbin with the PEEK plate. Additionally, the lead wires of the coils were fixed on the coil bobbins with an adhesive (TRA-BOND 2116).

Images attached to this report
VIS (EX)
tomotada.akutsu - 17:45 Wednesday 27 March 2024 (28994) Print this report
Comment to Height adjustment of ETMX (28780)

Maybe the following would not directly relate with this issue, but judging from the photo you attached, the tail of a PEEK-tie like one and the metal bottom plate seem about touching. If they touch with each other, such variation of resonant frequency may easily happen.

VIS (IX)
tomotada.akutsu - 17:39 Wednesday 27 March 2024 (28992) Print this report
Comment to Recovery of BF damper (28613)

The capton sleeved cables seemingly sit on the coil; shook will not move them?? The worst case would be that the sleeves just sliding off the coil, and being located in-between the primary and secondary coils. Will it not happen with this setup?

VIS (IX)
ryutaro.takahashi - 17:32 Wednesday 27 March 2024 (28991) Print this report
Comment to Recovery of BF damper (28613)

[Takahashi, Ikeda, Washimi]

We repaired the H2 LVDT for the BF damper. The pin-socket connection on the primary coil was loose because the Kapton insulation tube was too long. The tube was shortened and the pin-socket was reconnected fast.

Images attached to this comment
VIS (EX)
ryutaro.takahashi - 16:53 Wednesday 27 March 2024 (28990) Print this report
Comment to Height adjustment of ETMX (28780)

[Takahashi, Ikeda, Hirata]

We checked the BF visually. We did not find any rubbing points around BF and inside the tube that the suspension rod goes through. We measured the TF from BF to BF by fixing the BF body. The measured TF showed simple 0.6-Hz resonance. This is consistent with the result of the simulation.

Images attached to this comment
VAC (MCE)
nobuhiro.kimura - 16:41 Wednesday 27 March 2024 (28988) Print this report
Comment to Dia. 400 flange at the MCE trance port has been attached (28960)
[Kimura, Sawada, Nakajima and mTakahashi]
On 25 March, to eliminate a loose fastening bolt on the top flange of the MCE that was expected to cause a vacuum leak, the fastening bolt was loosened at one end and retightened by diagonal tightening.
The tightening torque was 40 Nm, and the elastomer seal was reused.
VIS (EX)
ryutaro.takahashi - 16:40 Wednesday 27 March 2024 (28989) Print this report
Comment to Could not go to Aligned state (28983)

I tried the ALIGNED state. The GURDIAN stopped in waiting for "RMS<10 MN_OLDAMP_P MN_OLDAMP_Y". COILOUTFs of MN control have been saturated.

MIF (General)
tomotada.akutsu - 14:10 Wednesday 27 March 2024 (28985) Print this report
Noise hunting: tapping around OMC chamber

Summary

Referring PEM's tapping activies around the OMC chamber in the past (For example 27442, 26011, 27258, 25919), I manually (by my hand/fingers) tapped or rather touched around the OMC chamber. Everywhere was somehow sensitive, but particulary I confirned that some sticking out parts (or mechanically "weak" parts) of the vacuum pump unit attached on the tube in-between OMM-OMC was quite sensitive to the in-vac geophone in the OMC chamber. Moreover, the geophone's behavior itself is strange.

Background/Motivation

In O4a we found that still some acoustic coupling at the OMC chamber to the interferometer sensitivity was large. This coupling should be the first prioritized enemy for us to overcome for the better sensitivity. So far some PEM acitivies revealed that the invac geophone itself was largely responding to tapping the chamber. This would mean the vibration isolation situation in the OMC chamber would be, say, out of question, to the level that it would be even too early to discuss about stray-light noise. This coupling mechanism has to be fully revealed and to be taken care well enough at first.

Details

Firstly, I looked at the filter bank of the relevant invac geophone channel K1:PEM-ACC_OMC_VACTABLE_OMC_Y_OUT. (The relevant MEDM can be accessible by sitemap -> OMC -> OMC Dock -> GEOPHONE OMC; see 25919)In short or in conclusion, I am still not confident on what are activated  in this filter bank (see note below). I compared the filters activated in the filter bank with those for the other geophones, but could not become convinced fullily. This point should be clarified.

I firstly tried to rely on OUT channel after the filters, but I felt the behavior was strange and unuseful. Maybe due to the filters, the filtered signal showed large low-frequency surge when shook was applied, and the surge always started with going "positive". Whether this behavior would be real DC moves or not, the DC trend was not useful for my today's work. So I mainly looked at the singal just before the filter chain. As written in the note below, still there is a strange thing, though.

Anyway, I strated tapping. What surprised me was that my light stomping on the floor outside of the clean booth was clearly observed with the invac geophone. Also, I just tapped the top surface of the desk outside the clean booth, and it was also observable. Too sensitive. I maybe like to do the similar thing for the other place for comparison.

Next, I entered in the clean booth. I checked that the vacuum gauge attached to the OMC-OMM chambers showed 1.2e-5 Pa, so the inside of these chambers must be vacuum. Tapping around the vacuum chambers, I found everywhere was somehow responsible, but particulalry the vacuum pump unit was the worst (best response, in some sense, but worst for detecting GW). Particularly, some sticking-out parts such as a slender tube of a mass spectrometer, and manual handles for gate valves (there are two gate valves). The structure of the gate valve is thin, so the structure might be easily fluctuating. The white-ish support structure of the vacuum pump unit was also sensitive.

Although still the coupling path is not clear, one solution would be that these mechanically weak structures should be put away from the most sensitive part of the interferometer, the OMC chamber.

Note

  • As shown in Fig. 1, the input stage itself of this geophone signal is strange. For some reason the lower was bounded by something. Maybe as a result of this lower bound, the filtered signal always start with positive surge. Moreover, the low-frequency surging itself would indicate that the filter setting might be not good. I think that this should need to be checked at first from the bottom.

Images attached to this report
DetChar (General)
nami.uchikata - 13:12 Wednesday 27 March 2024 (28987) Print this report
Combined segment lists for O4a period
Daily segment lists are automatically generated, but I have made combined segment lists for O4a period for two flags, which are available at (System B)

/home/detchar/Segments/K1-GRD_SCIENCE_MODE_NO_IPC_ERROR/K1-GRD_SCIENCE_MODE_NO_IPC_ERROR_SEGMENT_UTC_O4a.xml
/home/detchar/Segments/K1-GRD_LOCKED/K1-GRD_LOCKED_SEGMENT_UTC_O4a.xml
AOS (Baffles & Beam dumps)
tomotada.akutsu - 10:29 Wednesday 27 March 2024 (28984) Print this report
IY WAB released.

Hirata, Akutsu

By detaching two trianglar retainers, we released the WAB at IY, which had been restrained in 28797. (Note that in 28797 the title is "released" but in fact "restrained" on that day... funny)

This is the last WAB released in the Noto earthquake recovery.

Images attached to this report
VIS (EX)
dan.chen - 9:25 Wednesday 27 March 2024 (28983) Print this report
Could not go to Aligned state

This morning, I requested Aligned state to ETMX suspension, but it could not reach. I waited about 30 min, and just gave up it.

I hope it is just I needed more patience or luck.

Comments to this report:
ryutaro.takahashi - 16:40 Wednesday 27 March 2024 (28989) Print this report

I tried the ALIGNED state. The GURDIAN stopped in waiting for "RMS<10 MN_OLDAMP_P MN_OLDAMP_Y". COILOUTFs of MN control have been saturated.

VIS (EX)
ryutaro.takahashi - 22:20 Tuesday 26 March 2024 (28982) Print this report
Comment to Height adjustment of ETMX (28780)

Though I tried to measure the TF in the BF height of 1520um, the TF did not change. It is necessary to check around the BF visually.

Images attached to this comment
PEM (Center)
takafumi.ushiba - 17:52 Tuesday 26 March 2024 (28981) Print this report
Comment to MCF/MCE shaking/tapping test (28943)

Washimi-kun,

I have several questions on the measurements and the results.

1. What are the frequency regions you injected white noise?
2. Are the excess noises linearly coupled (Do the excess noises have a coherence with injected signals)? Or, nonlinear coupling?
3. Does the reference signals see some signals (real vibrations)? Or just see the noise?
4. How about the relation between injected vibration and vibration on the table? Smaller, comparable, or even larger?

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