• Could you also put a summary of the screw lengths sticking out of the suspended breadboad before and after making it sit down? Those are also important information to look back.
• Note1: As shown in the klog28593 attached file, the distance from the center of PR2 mirror (or its chamber flange?? I saw the laser level in red seemed displaced from the RM's wire break...) to the top of the suspended breadboard before making it sit down was around 390 mm, while the nominal expectatoin was 380 mm, so the suspended breadboard was lower than the nominal. Anway we met this in the past and maybe we will not need to "modify" this; see klog17595. At that time we put a 10 mm thick aluminum plate under the mid baffle to compensate the height. Anyway this kind of explanation for such a descrepancy should be repeatedly added for future workers.
• Note2: the suspended breadboard was a little bit tilted; to put it concretely, the PR3 side of this breadboard was lower. Maybe at that time we let it go because we did not want to touch POP-POM anymore, and I believe it would be the same this time as well.

The screw lengths before fixing breadboard are as follows:

[Hirata, Dan Chen-san, Ikeda-san]

We continued adjusting length Oplev by Traverser.

• Firstly, we checked tilt Oplev. It's little bit off centered, so we aligned it to [0,0] moving IM pitch and yaw.
• For centering length Oplev we moved Traverser to AR side(X: -15000um, Y: -15000um). We centered tilt Oplev too(IM YAW Pico: -3250), and adjust V2 OSEM position.
• Length Oplev value was slightly increased, but no significant change. We talked with Ushiba-san.
• After that, we realized that power cable which I connected to the Traverser driver was 18V. (24V is correct)
• We recovered Traverser to this morining situation.(move Traverser X:+15000um, Y:+15000um)
• When I recovered V2 OSEM position, I touched small hexagon. It pushed IM Yaw direction, and we lost Oplev tilt.
• We recovered tilt Oplev by IM Yaw Pico.

Next week, we will try to move Traverser by 24V.

[Hirata, Washimi-san, Ikeda-san]

We tried to adjust length Oplev by Traverser. But we didn't finish it.

• First, Ikeda-san and Washimi-san did cabling and connected 24V power cable for Traverser.
• We checked and adjusted tilt Oplev.
• Moved Traverser [x, y]=[-1500um,-1500um] (It's Traverser coodinate system), and IM Yaw pico -3550steps. Tilt Oplev changed more significantly than last week trial. We think Traverser is working now.
• Length Oplev horizontal value changed from 280(before moving Traverser) to 278.9. It decreased little bit.
• When we checked IM H2 OSEM, We lost tilt Oplev (again). We recovered it.

Tommorow, after opening chamber top, we will try to measure Traverser position directly.

[Hirata, Dan Chen-san, Ikeda-san, Ushiba-san]

We checked Traverser position, and moved it to the previous position. Finaly, length Oplev was recovered.

• Removed bolts, and opened PR2 chamber top part.
• Measured Traverser position by caliper and compared with old data (2022/7/26) which was measured before closing chamber.
• We confirmed Traverser works well or not. Direction is correct.
• We moved Traverser to previous position(2022/7/26). -1100um to y direction, and -3000um to x direction.
• We measured Traverser position by caliper again. It was almost recovered to previous position(2022/7/26).
• At the same time, length Oplev was recovered.
• We closed chamber top.
• Adjusted tilt Oplev by IM Yaw pico -2400 steps.
• Length Oplev is HOR:-13.4um.
• We checked IM OSEM(3700～7640). All flags are not touching.

After that, Ushiba-san realized BF damper V1 is around edge of calibration line(about 5800). Tomorrow, we will open chamber top, and see BF and BF damper situation.

Detail on BF V1 LVDT:

According to the log of PR2 LVDT calibration (klog2906), BF LVDT V1 was calibrated between -5500 and 3000.
Current value is about -5800: that means we are not sure LVDT is now in linear range or not.
I think this situation is not good.
However, this situation seemed happened long before the earthquake, so it would not be a critical issue and I'm not so sure if it should be fixed or not.

Note:

BF V1 LVDT signals can be changed when SF GAS position changes; however, V1 value won't be changed so much even at ALIGNED state because current error signals of SF GAS is just 10 um or less.

[Hirata, Dan Chen-san, Ikeda-san, Takahashi.R-san]

We checked BF and BF damper tilt, and adjusted BF damper LVDT V1, V2 and V3 secondary coil.

• We opened PR2 chamber top.
• We checked tilt of Bottom filter and BF damper by 2 laser levelers from opposite side. We can see only 0.5mm or 1mm difference, but it's within measurement error by laser leveler. It looks no big tilt.
• Takahashi-san talked with Ushiba-san. We should adjust Secondary coil to calibration line "0"(klog:2906).
• We found BF damper V2 and V3 LVDT secondary coil holder were tilted.
• We locked BF damper and started adjusting work.
• We moved Secondary coil to calibrated "0" positon. Targets are V1:-1103, V2:-516, V3:-142. The result is attached.(pic4:Before, pic5:After adjusting)
• V1 Secondary coil holder reached to the limit. So V1 is little bit far from the target(-1552).
• BF damper was released.
• Chamber top was closed.

Tomorrow, we should check payload (Oplev, OSEM, earthquakestops) again.

[Hirata, Dan Chen-san, Ikeda-san]

We checked Payload part earthquake stops and OSEMs. We didn't find any bad point.

• First we aligned tilt Oplev by IM Yaw and Pitch pico.
• After that we checked OSEM flags. It looks not touching.
• We checked earthquke stops, and found TM HR side one was very close to the mirror.
• We locked RM, and change the distance around 2mm. We checked other earthquake stops too.
• RM was released.
• We aligned tilt Oplev again.
• Closed chamber.
• We investigated IM V2 60Hz issue. (Another report)

After that, I talked with Ushiba-san. He will take care of BF Yaw set point, and do health check.

[Hirata, Takahashi.R-san, Washimi-san, Ikeda-san]

We checked PR2 SF and BF LVDT yoke, and adjusted them.

• We opened chamber top part, and checked BF damper LVDT cables. We didn't find any cables which are touching.
• We found that SF LVDT screws were loose. Takahashi-san checked set point, and after tightening LVDT screws, he changed set point.
• SF LVDT yoke was shifted. We fixed it.
• BF LVDT yoke was shifted too. We adjusted it.
• We adjusted tilt Oplev and checked OSEM positions. They are not touching.
• All earthquake stops are not touching.
• Washimi-san found IM OSEM V2 pin 5 (ground) was disconnected, so we fixed it. (It was reported klog:28707)
• We closed chamber.

I checked and took pictures of earthquakestops for PR2 payload.

I uploaded those pictures to KAGRA Dropbox here.