With Lucia and Yamamoto-kun.

Summary

We went ot the tunnel and realized the IP coil driver is broken. Its number is S1706250.

Details

Before going to the tunnel, at the control room we did some tests, which failed:

• We tried moving the IP with DC actuation and also with a line and
• We tried measuring a transfer function.

Nevertheless, we were able to move the IP using the horizontal fishing rods, which suggested the problem was outside the vacuum chamber. The current position of the IP is as follows:

• L: -74 µm,
• T: -47 µm and
• Y: 4034 µrad,

which is relatively close to the set point (see the commented entry).

In the tunnel we realized the coil driver was off. We turned it on but after a few seconds it turned itself off. According to what I have heard from experts this symptom suggests an electrical ground problem. We need to replace the coil driver. 

With Tomura-san, Yamamoto-kun and Lucia.

The suspension was recovered and  it's back in ALIGNED state.

We changed to high power coil driver. The new one's S number is S1706255.

We measured the transfer function for IP-L and it looks good:

• Directory: /kagra/Dropbox/Subsystems/VIS/TypeBData/SR2/TF/Measurements/20200518/
• File: SR2_IPL_exc.xml

In case you don't see the picture attached please click here: entry 14401.

Further investigation about the origin of the event suggests the cause was not an earthquake. The description of the picture is as follows:

• The SR2 event happened at 23:42 UTC on May 7th when there's no earthquake.
• The seismometer in the BS area clearly shows a perturbation at 00:33 UTC on May 8th, but nothing at 23:42 UTC on the 7th.
• The perturbation mesured by the seismometer affected the feedback in SR3 IP.
• Such perturbtion was likely the earthquake which happened southeast of Honshu island. See this report.

There will be a report in the VIS General section about this event, please stay tuned.

In case you don't see the picture attached please click here: entry 14401.

Further investigation about the origin of the event suggests the cause was not an earthquake. The description of the picture is as follows:

• The SR2 event happened at 23:42 UTC on May 7th when there's no earthquake.
• The seismometer in the BS area clearly shows a perturbation at 00:33 UTC on May 8th, but nothing at 23:42 UTC on the 7th.
• The perturbation mesured by the seismometer affected the feedback in SR3 IP.
• Such perturbtion was likely the earthquake which happened southeast of Honshu island. See this report.

This report is related to entry 14404, in which the BS actuation is also shown.

I checked the other PEM channels around SR2.

No any strange large signals are detected.