KAGRA Logbook

[Takahashi, Washimi, Hirata]

We did preparation for installation of SRM IRM dampers.Today, we locked suspension, and Breadboard. After that we removed Mid-size baffles from the breadboard.

1. Lock IP and Topfilter
After opening the top flange of chamber, we locked IP and Topfilter. We covered suspension by Seiden-sheet. (Guardian status was already SAFE mode.)

2. Check the mirror height
We checked the mirror height by laser leveler. Beam height is indicated on SRM chamber(Main mark is on +Y+X side. Copy is on -Y+X side. pic1, pic2 )
Unfortunately, Beam height is close to the edge of side flange. So laser leveler could only be used near the center.(pic3) We put green laser leveler at the +X side, and align to the Beam height mark on the chamber.
And put red laser leveler at -X side, and align it to the +X side green laser leveler(pic4). Recoilmass front ring has center mark. We can see the laser leveler height and the recoilmass center line.

・+X side (Green line) looks same as recoilmass center line.(pic5)
・-X side (Red line) looks 3 millimeters away from the recoilmass.(pic6)

3. Check the Bread board height
Laser leveler can only used around center of side flanges. So we can only check the height near the center.

・+X side (Green line) is 380.5mm.(pic7)
・-X side (Red line) is 383.0mm.(pic8)

4. Lock the Breadboard
Turn 4 foot screws to lower that until they touch the block. After that, added 4 masses(Total 20kg) on the breadboard for locking. (pic9)

5. Lock the Suspention
Bottomfilter, IMR, IM, RM and TM were locked.

6. Mark the Mid-size baffle position
To record the current baffle positions, 3 blocks(AL clamps) were set on each baffle.(pic10)

7. Remove Mid-size baffles
We removed 4 fixed clamps, and removed mid-size baffles(AR side and HR side). Clamps for the mid-size baflles remain on the bread board.(Note that those positions have been changed.) (pic11)
Removed Mid-size baffles are on the tables have 4 pillars, and wrapped by plastic films. 4 pillars preventing plastic film touch baffles. (pic12)

*We weighed removed baffles.

・HR side : 4.94kg
・AR side : 4.931kg

Today's pictures are https://www.dropbox.com/scl/fo/1dw0adstbz35z85i0vd91/AJlOguQbuxD332fX1ZaIiYE?rlkey=xv1ztcd0wli70ukd0hxlslcl0&st=sfhiadap&dl=0