In addition to this report by Hirata-san, we checked the inclination of the Recoil Mass of the TM by a laser leveler.

A rough estimation via the attached figure shows that the RM is tilted upward about 13mrad~4/300 with facing to the +x direction.

By the way, if the notes in the photo in 28380 is collect, the tilt direction of RM might be aligned to what it should be for TM; the PRM should face up in the BS direction by 1/300 along the IR beam line. But the estimated value 4/300 might be larger than this nominal one... hmm.

Referring as to Fig. 11 of this paper, ~0.01 mrad pitching difference of an OMSE body and its flag might be acceptable.

[Hirata, Dan, Rishabh]

We picked up fallen magnets on the breadboard and security frame, and rescued the magnet inside recoilmass. All magnets are measured polarity.

・First we locked recoilmass for preventing swinging recoilmass.
・We picked up two fallen magnets on the breadboard and the security frame.
・One magnet was inside recoilmass. Dan Chen-san pushed it by allen key, and it was fallen on the security structure. So we can picked it up easily.
・We measured magnets polarity by porarity checker.
・After released recoilmass, we checked IM OSEM flag status after removing the magnet inside recoilmass. It seems that there is no big difference.

[Hirata, Dan, Washimi]

With Dan Chen-san, we soaked fallen magnets in Aceton for removing adhesive. And left them inside hume hood. We checked them in the evening, but adhesive was still hard.
With Washimi-san and Dan Chen-san, we looked for spare magnets. Dan Chen-san found them at PR3 clean booth changing room.
1 set for PR, 1 set for SR. (1 set means 4 magnets, 4 pillars and 4 bases.)

[Hirata, Aso-san]

Aso-san and I checked polarity of magnet on the mirror by KANETEC TM-801. The polarity is "S".

Yesterday, Takahashi-san and I checked Gain polarity and matrix on the MEDM screen. According to that and result of measurements, PRM Testmass magnet polarity should be as below. Fallen magnet was named A,B and C. (please see attached picture.)

• H1 Gain:+, Polarity:S (not fallen one)
• H2 Gain:-, Polarity:N → magnet C  (It was inside recoilmass, and has short base one. Measured polarity was N.)
• H3 Gain:+, Polarity:S → magnet A (on the breadboard one. Measured polarity was S.)
• H4 Gain:-, Polarity:N → magnet B (on the security frame one. Measured polarity was N.)

[Hirata, Ikeda-san, Dan-san]

We assembled 4 spare magnet assemblies for PRM Testmass. Magnets are glued with bases and pillars. We left them inside PR3 cleambooth.

Hirata, Ikeda,Aso

This is a follow up entry to this: https://klog.icrr.u-tokyo.ac.jp/osl/?r=28427

We tried to center the OpLev of PRM by tilting the IM with the moving mass.

• Since we knew that the H1 OSEM flag is close to touching the upper sidewall of the coil, we first locked the IRM and moved the H1 OSEM body as high as possible.
  • The OSEM body is mounted to the IRM sidewall through an interface plate with a bunch of M4 screws. The corresponding holes on the interface plate are intentionally made larger (7mm) to allow for the adjustment of the position.
  • We were able to move the OSEM body up by about 1mm at this time.
• We then tilted the IM with the moving masses both in pitch and roll. The roll adjustment was necessary to prevent the other horizontal OSEMs from rubbing.
• As we tilt the IM in pitch in the direction to move the OpLev beam towards the QPD center, the H1 OSEM flag moves up and eventually touches the OSEM body.
• So we lowered the IM by moving the BF fishing rod. However, after several trials, the BF keystone reached the lower end and it was no longer possible to further lower the IM.
• The OpLev beam spot was still on the edge of the QPD.
• We figured that the only way to continue the IM tilt adjustment is to modify the interface plate of the H1 OSEM to allow it to be moved further up.
• We took out the H1 OSEM and brought back the interface plate.
• We plan to make the 7mm holes elongated in the vertical direction. Alsoa part of the plate needs to be cut by a milling machine to allow for a large vertical adjustment.
• Hirata-san will do this modification at NAOJ ATC on Monday morning and bring the plate back to Kamioka on that day.
• Takahashi-san and Hirata-san will continue to try the adjustment of the PRM pitch with the modified interface plate.

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

We assembled PRM IM H1 OSEM with interface plate which I did additional machining at Mitaka yesterday.

• IM H1 OSEM and modified interface plate were assembled.
• We locked IRM.
• We installed it to the IRM, and adjust the position almost to the center of OSEM flag.

[Takahashi, Hirata, Dan, Washimi, Ikeda]

We tried to align the TM and started the preparation for the magnet gluing.

1. Lifted the BF keystone to the setpoint with the FR.
2. Confirmed if the flaps on the IM are touching the OSEMs. Any flaps were not touching the OSEMs.
3. Align the TM using the moving masses on the IM with the pico-motors. The TM could be aligned to the Oplev center.
4. Confirmed if the flaps on the IM are touching the OSEMs. Any flaps were not touching the OSEMs.
5. Fixed the IM and IRM with the stoppers.
6. Made the RM sit on the EQ stop (catcher) and bound the RM to the catcher with the belts.
7. Fixed the TM to the RM with the stopper so that the TM surface can be parallel with the RM surface.
8. Removed the H2, H3, and H4 OSEMs from the RM.
9. Attached the gluing jig into the H3 position. The magnet base fitted the TM surface. The position of the magnet base with the gluing jig was lower than the gluing seal on the TM by 1mm. The H1 OSEM was higher than the survived magnet by 1mm. This corresponds to the rotation of the TM.

Picture of H3 on PRM

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

We tried to set laser leveler to check the roll of PRM Testmass, and finaly we decided we can check it by 2 laser levelers.

• First, we used small tripods for adjusting height of laserleveler inside vacuum chamber, but it's impossible to align laserleveler with wirebreakers. because there is a Mid-size baffle infront of the mirror.
• We put laserleveler on the security frame with some spacer and adaptor which can adjust height 5 or 6mm. First wire breaker were small and position was too high, so it's difficult to use them. But we were able to hit the laserleveler on the second wire breaker.
  We used green laserleveler for left side, and red laserleveler for the other side.

Next step, we started releasing suspention.

• We re-assembled 3 OSEMs with Recoilmass.
• RM, TM, IM and IRM were released.
• Takahashi-san checked Oplev, and confirmed TM position is not changed before locking suspention.

Tomorrow, we will start checking the roll of Testmass.

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

We measured roll of PRM TM, and recovered it. After that, we started setting glueing jigs, and finished it. 

1.TM roll measurement

• We set laserleveler at the position we tried yesterday.(pic1:-Y ,pic2:+Y)
• -Y side is 3mm higher than +Y side.(pic3)

2.TM roll and Oplev position recovering

• Takahashi-san recovered roll by IM moving mass. We set +Y and -Y side laserlevelers at the target height, and we checked both 2nd wire breaker's position each after moving IM.
• We cheked Oplev, and centerd it by adjusting IM Yaw and Pitch. We checked that any IM flags and earthquake stops are not touched.
• After recovering TM roll and Oplev position, we measured RM roll. -Y side is 1.5mm higher than +Y side. We measured height of RM "stands-off"(Those are parts at the side of RM to keep wire position). Because it's center of RM.(pic4:+Y, pic5:-Y, 6)

3.Setting gluing jigs

• IRM, IM, RM and TM were locked. After that, H2, H3 and H4 OSEMs were removed.
• We set glueing jigs and magnet. And checked gap of magnet base and TM surface. We saw small gap.
• We align TM with RM by earthquake stops for TM. The length of the earthquakestops on the HR side will be the same if the HR surface is parallel to the RM.
• After aligning TM, we couldn' see any gaps by visual inspection at all glueing jigs.(pic7, 8)
• Note that, spare magnet bases don't have cross shape grooves at the bottom. (I'm sorry. I should modify drawings.) (pic9)

[Hirata, Dan Chen-san]

We measured magnetic flux density of PRM TM magnets by KANETEC TM-801. We measured 3 times. Average is as below.

Original magnets(fallen one)

• H1 is not fallen. We cannot measure. 
• H2 (magnet C): 282.3 mT (Pol.N)
• H3 (magnet A): 283.7 mT (Pol.S)
• H4 (magnet B): 280.7 mT (Pol.N)

New magnets

• H1: 283.7 mT (Pol.S)
• H2: 284.0 mT (Pol.N)
• H3: 289.7 mT (Pol.S)
• H4: 295.3 mT (Pol.N)

I attached pictures of 2nd wire breakers after recovering TM roll. (pic1, 2) Laser leveler hit on the 2nd wire breaker. Pic3 is target position.

[Hirata, Aso-san, Dan Chen-san, Ikeda-san, Komori-san, Takidera-san]

We glued magnets on the PRM Testmass AR side. H2, H3 and H4.

• We used TRA-BOND 2116.
• Magnet polarity are H2:N, H3:S, H4:N.
• Aso-san checked amount of adhesive several times, using one spare magnet base and fused silica plate.
• After that, we put them into glueing jigs which we set last Friday.

We will release magnet jigs tomorrow noon.

Hirata, Dan, Ikeda, Komori, Aso

We brought this suspension to the following state:

• OpLevs are centered (both tilt and length)
• All the OSEMs are in good range.

However, as reported by Ushiba-san, the TFs are strage. So we need to find what is rubbing.

Removal of the gluing jigs

After curing the glue for 24 hours, we removed the gluing jigs from the mirror. All the magnets are bonded well now.

We then put back the coils.

OpLev centering

After releasing the mirror, we found that the OpLev beam shifted a lot in downwards. This means the mirror rotated a lot in -pitch, which is expected from the increased weight of the magnets.
The mirror was originally tilted in +pitch a lot. So this is a good sign.
We moved the IM moving mass to recover the OpLev beam centering. Along the way, we had to adjust the positions of the IM OSEMs because some of them were rubbing.
In the end we were able to center the tilt QPD with all the OSEMs in good positions.
We then found that the LEN OpLev is shifted by ~300.
We corrected this using the traverser just like PR3.
However, even after this, we could not bring the Guardian to the aligned state (oscillation happened).
As revealed by Ushiba-san's health check measurements, something must be rubbing and the TFs are quite different from the reference. This is probably why the local damping loops were unstable.

Pictures of the magnets.

Work done on 2024.02.06.

> We then found that the LEN OpLev is shifted by ~300.
> We corrected this using the traverser just like PR3.

PRM Traversers were moved.

X: -450 um
Y: -450 um

Traverser Direction

(This work was done on 2024/2/5)

I attached pictures of TM magnets after assembling OSEMs.

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

We checked OSEM flags and cables which are touched or rubbing something.

• One cable from IM was touched to the IRM parts.(pic.1, 2)
• Some OSEM flags were touched or very close to the hole wall.(pic.3-8)
• All earthquake stops were not touching.

After locking IRM and IM, we started to fix them.

• First, we modified cabling little bit. It is fixed to the BF bottom plate. PEEK cable clamp was not tightened so much. So we can untighten screws easily, and pushed  it little bit (about 2 or 3mm). Now we can see gaps between this cable and IRM. (pic.9)
• Once we released IRM and IM, and checked OSEM flags and Oplev signal. We need to adjust Yaw direction, but Ushiba-san realized BF was rotated little bit, and it's within control range. OSEMs were almost same situation.
• We locked IRM and IM again. And moved OSEM holders to center flags as possible as we can.(pic.10-14)

After those works, Ushiba-san run health check script. According to Ushiba-san, vertical results are not good. We need to check more tomorrow. 

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

We checked PRM suspention again.

• Earthquake stops and cables were not touching.
• We took pictures of inside BF yoke from 4 bottom holes. (pic1-4, 5, 6)
• We can see small gap between yoke and coil. It is slightly different from each other.  
• We can see something inside yoke. It might be a parts (lever for yaw picomotor) or screw head, but we are not sure. (pic2, 3, 7, 8)

After Ushiba-san's health check, we started preparation for tightening locating clamps for piano wire.
We prepared tool and checked procedures by old k-log(16348).

Tools are below.

• jack (M38 × 3 mm per thread)
• an hexagonal tool (#8) (for pushing up RM from the bottom)
• Teflon sheet
• Spacer

Procedure is as below.

1. Lock IRM and IM by earthquake stops.
   (We added additional clamps to prevent IRM goes up accidentaly, and put locking screws between IRM and IM to prevent IM accidentaly goes up.)(pic9, 10, 11)
2. Lock RM and TM, and remove OSEMs from RM. 
3. Remove 2 side plates of IRM with OSEMs. (need to disconnect cables)
4. Remove outer locating clamps for the tungsten wire.
5. Released the mirror from the RM.
6. Put peek spacer between between the clamped tunsten wire and RM just below the wire breakers.
7. Jack up RM 2mm, using lower earthquake stops for support. We can use bubblelevel to avoid large tilt. We can access screws for clamping piano wires.
8. Lock TM to RM.
9. Check piano wires are inside grooves, and tighten screws of locating clamps for piano wires. (2Nm)
10. Release TM from RM.
11. Jack down RM, and confirm RM is supported by earthquake stops from security structure.
12. Remove peek spacers that are between the RM and the tungsten wires below the wire breakers.
13. Lock RM and TM.
14. Put OSEM back to the RM.
15. Release TM and RM.
16. Put back outer locating clamps for tungsten wires, and check wires are inside grooves.
17. Tighten outer locating clamp screws. (2Nm)
18. Reassemble IM side panels. (Connect cables)
19. Release IM and IRM.

Tomorrow we will continue from procedure "2".

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

We finished work for tightining locating clamps for PRM TM piano wires. We followed procedure which was written on k-log28557. I attached pictures before and after work.(pic1:-Y before, pic2:-Y after, pic3:+Y before, pic4: +Y after)
After this work,

• Suspention was released.
• Oplev is not centered. We need to check and align it.
• We need to check OSEM signals. It should be adjusted.
• We covered aluminum foil over the side door of PRM chamber. 

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

1. Work after tightning clamp screws

• In the morning, we centered Oplev. After that, all OSEM signals became good value. So we didn't move any OSEMs.

2. Bottom filter check

• We started preparing opening chamber top part. First, we removed many bolts for chamber top. We keep those bolts in 2 plactic boxes which we got around mirapro area.
• After Miyoki-san's cleaning work, we opened chamber top part by crane. Beforehand, we locked payload for the safety.
• We locked SF GAS filter. And we locked BF itself by 3 side screws.
• We removed 16 magnets which were assembled on the yoke, and removed yoke part.
• We checked inside coil. We didn't find any suspicious parts inside coil and yoke. 

(Next trial will be posted by Takahashi-san.)

After checking the inside of the actuator coil, we tried to see the inside of the BF body with a fiber scope from the top holes, but it was difficult. We attached the yoke again to see the behavior of the BF keystone. When we pulled the keystone down by hand, the LVDT signal was critically damped. When we pulled the keystone up by hand, the LVDT signal oscillated several times but bounced at a lower limit a little below the present level (around 730, setpoint is 1280). Something, e.g. the bar on the rotating receptacle, would be touching the bottom plate.

[Takahashi, Hirata, Dan, Washimi, Ikeda, Aso]

We continued the adjustment of the suspension opening the top belljar.

1. The height of the BF keystone was almost at the lower limit. We lifted the keystone with the FR by ~30000 steps. We adjusted the horizontal OSEM position on the IRM so that the flaps could keep a clearance. The height of the BF keystone was set to ~1800 (the setpoint was 1280). The behavior of BF GAS became natural.
2. We attached all magnets to the yoke on the BF. We released the TM, RM, IM, IRM, and BF.
3. When we released the SF keystone, we found the BF V2 coils were very close to each other. We adjusted the position of the secondary coil. The V2 signal was changed from 6400 to 600 in um.
4. We tried to set the height of the SF keystone to -500 (the setpoint was 0). Though the SF keystone was close to the upper limit, the LVDT signal showed -1900 um. Though we tried to lift the keystone with the FR, the signal had no response. When we touched the Dsub connector for the SF LVDT, the signal jumped to 2000 um.
5. The cable connection at the connector was unstable. We fixed the connector on the SF bottom plate with peek ties.
6. We removed four ballast masses (φ40 x 3t) from the BF. The SF LVDT signal changed from 2000 to 1300 while the BF V1~3 signals changed from 4700 to 60, 6400 to 50, and 3900 to 60 respectively. The amount of changed signal between the SF LVDT and the BF V1~3 were inconsistent.
7. We calibrated the SF LVDT compared with the BF V (plot). The coefficient was about 0.2um/count.

[Takahashi, Washimi, Ikeda, Aso]

We continued the adjustment of the suspension opening the top belljar.

1. We checked the TM height with a laser leveler. The wire braker on the RM was consistent with the flange center level.
2. We adjusted the height of the secondary coil for the SF LVDT so that the LVDT signal could be 0 count (-1938 um). We calibrated the SF LVDT (plot). The coefficient was 0.23um/count.
3. We found the signal of the BF LVDT was 0. We checked the resistances of the coils at the feedthrough. They were normal. After reconnection of the Dsub connector to the feedthrough, the LVDT signal was recovered. The signal value was 1800 um. The cable connection became stable.
4. When we pulled down the BF keystone, it touched a mechanical lower limit soon. The limit was at 700 um at the last time. It's strange.
5. We pulled up the BF keystone with the FR from 1803 to 2715 um by -360000 steps. The RM height was changed by about +1mm by eye with the laser leveler. Finaly the BF keystone was set to 2549 um, then the RM height was consistent with the flange center level.
6. We adjusted the OSEM positions and insertions taking the alignmemnt of the TM to the Oplev.
7. We put the top belljar on the chamber.

[Hirata, Washimi-san, Ikeda-san]

We checked IM OSEM flags.

• First, we checked IM H2 coil by LCR meter. The value was almost same as acceptance check list.
• We found IM H2 OSEM flag is touching.
• H2 OSEM holder is reached to its limit.
• Aso-san advised us that all OSEM plates should be modified except H1. H1 was already modified.
• We removed OSEM holders.
• We realized V2 OSEM holder was already modified(7-D7 screw hole is D10), and we can adjust it to the good position.

OSEM holders will be modified at Mitaka.

• Lateral OSEM(H2,H3) D7 holes should be long hole to move it more higher position.JGW-D2415637
• Top OSEM(V1,V3) should be modified as same as V2 (D7 to D10).JGW-D2415636

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

We assembled PRM IM OSEM holders which were modified at Mitaka, and adjusted OSEM position. All OSEM flags are not touching.

• We assembled OSEM holders and OSEM with IMR.
• Payload part were released and checked tilt Oplev. Oplev was not on the QPD. It was shifted Yaw direction, and little bit Pitch direction. We adjusted it to "0".
• After recovering tilt Oplev, we checked OSEM position and adjusted again.
• Almost all OSEM signals were out of range. So we adjusted them. Target was 6000 counts.
• We checked tilt Oplev and OSEM position again. And adjusted bad one again. It looks all OSEM flags are not touching.
• We checked earthquake stops, and closed the chamber side door.

After this work, Takahashi-san talked with Ushiba-san. And we realized BF and SF LVDT position was far from the set point. So, Takahashi-san did off-loading.(It will report later.)

I offloaded the SF and BF GASs. The IM OSEMs were set around 6000 counts for H and 9000 counts for V.

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

We measured Traverser position. The result is attached.(pic.1) Previous position was klog:21607(2022/7/26). Pic.2 shows rough difference value between today and 2022/7/26.

[Hirata, Dan Chen-san]

We took photos for PRM payload earthquake stops. I uploaded today's photo to KAGRA dropbox.

During this work, we found two earthquake stops for test mass AR side were very close to the mirror surface(within 1mm?). We talked with Takahashi-san and Ushiba-san, and decided to withdraw them.

I checked PRM "SF GAS" LVDT cable resistance and inductance at the feedthrough flange with flip cable (flange port No.3-6). According to the klog:28586, this in-vac cable connector was unstable and fixed. So we measured it.

No ground fault and no interconnection between each pins.