Comment to Long term stability of PRFPMI (Click here to view original report: 12683)

Wow. Great.

Comment to Long term stability of PRFPMI (Click here to view original report: 12683)

Oh man...

Comment to Long term stability of PRFPMI (Click here to view original report: 12683)

Thank you for your great work!

But, ..., Alaska earthquake may break the lock. Also, very large earquake occurred in Jamaica, maybe it will be difficult to lock the interferometer tonight.

Long term stability of PRFPMI

More than 4 hours lock!!

Comment to Stopped the Trubo and dry pumps at 3,5,6,13 (Click here to view original report: 12667)

I checked the drift of the GAS output for the Type-A and Type-B suspension.

Type-A, ITMX F3 and ITMY F2 and F3 drift is larger.

Type-B BS GAS drift larger. (Maybe, the temperature drift is larger around BS area.)

CARM signal demod phase optimization

- The demodulation phase for the CARM signal (RF45) rotated by 90 degree. I cabled the Q-MON of the I/Q demod board to the CARM servo. This is because the limitation of the rotation angle of the analog phase shifter as reported in klog12668.
- Now the CARM loop UGF is 50 kHz, and seems much more stable. I left the IFO locked, and we will see the long term stability.
- I also tried to transit 3f MICH signal to 1f, but it still cannot be stable enough. Actually the RF17Q did not have coherence with RF51Q. I will try again tomorrow.
- DARM OLG was measured again.

Replacing LVDT Combiner for ETMX

[Kamiizumi, Shimode, Tomura]

Shimode-san modified one board (S1706801) of the LVDT Combiner (S1706809).

Coils for Ch.4 and Ch.6 were laid down to reduce the crosstalks from adjacent channels.

This chassis was installed to EXV2 rack as a replacement and former LVDT Combiner for ETMX (S1706805) was brought back to Mozumi.

Comment to Stopped the Trubo and dry pumps at 3,5,6,13 (Click here to view original report: 12667)

Many thermometers in the corner station such as MCF, PR2, SR2 show 0.3 C temp reduction maybe due to turbo pump stop.

I heat up a little bit in the corner station, however not enough at all. we need to put more heater in the corner station.

(Corner)
Delonghi Heater
C-HT01:25C/L4(~1200W) -> L5 (~1500W)
C-HT02:26C/L4(~1200W) -> L5 (~1500W)
C-HT03:26C/L5(~1500W)

SUNRISE Heater
C-HT04:26C/L3 (~1200W)
C-HT05:26C/L2 (~700W)

Spurious coupling of BF LVDTs: Combiner modification made little impact

[Miyakawa, Kamiizumi, Tomura, Shimode, Okutomi]

• We replaced the LVDT combiner for the ETMX BF LVDTs to a modified one.
  • The modified chassis has rotated inductors by 90 deg on one of the two boards.
  • This modified board is assigned to the horizontal LVDTs, while the verticals have the initial board-mounting configuration.
• We measured the transfer function in the longitudinal DoF of the BF.
  • The result was similar to the previous measurement, nothing improved. (see the figure below)
  • It means that the inter-channel couplings in the LVDT combiner was not the main reason of the spurious coupling at higher frequencies.
• I suggest some scenarios to explain this spurious coupling.
  • The main coupling path could be the LVDT-actuator unit itself where the receiver coil of sensing and the actuator coil are shared.
  • The mechanical transfer function has poor overall gain due to the position the actuation force applies on.
  • Geometrical configuration of the sensing and actuation coils can cause the coupling.
    • Because the IP and GAS coils also have the coupling with similar characteristics even without sharing the sensing and actuation coils.
• A better way to understand this spurious coupling is to measure the pure actuator-to-sensor coupling and investigate the setup to reduce it.
  • A prototype BF LVDT unit (could be in NAOJ Mitaka) sounds useful to test it.

Modification of the Common Mode Servo for Summing Node

[Shimode, Tomura]

In the morning of Jan. 24, 2020, we modified the Common Mode Servo for Summing Node (S1809503) in the ALS1 rack.

The resistor R173 on the CM Servo Main Board (S1809477) was changed from 10kOhm to 91kOhm to reduce the gain of the slow path output offset to 1/5.

Comment to Channels affected by DARM DoF (Click here to view original report: 12658)

I additionaly checked ETMX IM damping channel and they are affected by PCal lines.

More information is available here.

https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11426

 

Following link is list of channels which is affected by DARM DoF. It maybe better to avoid to use these channel in noise source study.

https://github.com/gw-detchar/tools/blob/master/GlitchPlot/Script/DARMaffected.dat

OMC QPD centering loop OPLGs

Attached are the current OPLTFs of the OMC QPD centering servo.

Yaw loops are OK.

The DOF1 Pitch is marginally stable because I added more agressive roll-off filters only to this loop.

The DOF2 Pitch is more problematic as the notch at 9Hz is deep. Therefore, I had to increase the UGF to 50Hz.

Placed portable PEMs to the IXC area

[YokozaWashimi]

For the check of the air compressor with new configuration, we placed two microphones and one accelerometer.

K1:PEM-SENSOR_RACK_IX0_BNC2 : Microphone around IX0 rack

K1:PEM-SENSOR_RACK_IX0_BNC3 : Microphone around the air compressor

K1:PEM-SENSOR_RACK_IX0_BNC4 : Accelerometer on the air compressor

Remove the IXC seismometer

[Yokozawa, Washimi]

We removed the IXC seismometer for R&D

Comment to Stopped the Trubo and dry pumps at 3,5,6,13 (Click here to view original report: 12667)

The temperature drift was small, and GAS output drift  would not so large drifting, I decided to stop the vacuum pumps during mid night.

If you find the serious temperature drift, please let me know.

Comment to RF45 demod phase (Click here to view original report: 12661)

Hi all,

My original thought was the following:
- as the DAC output is finally output by a Dsub-BNC converter, it will be useful if the output range (seen in MEDM) is from -5 to +5 V.
- as the analog phase shifter only receives positive voltage, it is safer to set limits.
- though it is not very useful, I thought it is fine if we can shift the phase by 90 deg. at max. 

Comment to Stopped the Trubo and dry pumps at 3,5,6,13 (Click here to view original report: 12667)

Two hour trend of the ondotori and Type-A and Type-B GAS filters

IYC OpLev vs IYC infrasound

0.75Hz peak in IYC OpLev is not observed in IYC infrasound microphone (red)

Comment to RF45 demod phase (Click here to view original report: 12661)

I discussed the mystery of current setting of demod. phase with Nakano-kun.

We may need some modifications on analog part
because DAC output range is not enough for changing from 0deg. to 360deg.

- Current setting of demod. phase is 8.362 Volts (see fig1)
- We can set demod. phase as between 0V and 5V (see fig2)
- We can do as between -5V and 5V by removing saturation block from k1alspll.
- We need to set as between 0V to 12V for changing from 0deg. to 360deg.

Stopped the Trubo and dry pumps at 3,5,6,13

For evaluating the drift of the temperature, we stopped the turbo and dry pumps of the 3,5,6,13 (pumps between BS and IXC/IYC)

10:05 started the turned off the turbo pumps

10:20 stopped the dry pumps and chillers