[Akutsu, Michimura]
We have installed a dichroic steering mirror on the PR2 suspended optical bench inside the vacuum chamber. This mirror will be used for the POP beam and the green beam for Xarm.
Since we couldn't see the POP beam right now, the mirror is roughly placed, and the pedestal is fixed with two clamps (see this photo and this photo). We checked that this structure does not block the PR2 oplev beam.
Before installation, we inspected the pedestal. It looked a little dirty (see this photo), and we wiped it before installation.
Picomotor cables are not connected yet (see this photo).
Next:
1. Put picomotor cables.
2. Adjust the alignment and position of the mirror using beams.
3. We might have to replace the pedestal with cleaner one before pumping down.
I fogot one tip: the obelisk post is 342 mm tall, and the mirror holder here is 8822-UHV, which is 34.9 mm from the bottom to the assumed mirror center, while the height of the suspended optical table (set by VIS) in the PR2 chamber is nominally 380 mm from the top surface to the interferometer beam line. So a spacer with 3mm thickness should be required inbetween the obelisk post and the mirror holder if you like to "more precisely" tune the height.
In addition to that, please note that the main beam flys with launching up around PR2 at the rate of 1/300; considering this fact, let's say we would need to add 5 - 6mm in total if you might like precise life, as the post would be ~ 70cm away from the center of the PR2 mirror.
About the dirty, I'm sorry but I can say I knew this would happen from the first; as I learned the PR2 chamber won't be in vacuum in phase 1, so I asked to omit vacuum comaptiblilty and got it auickly with inexpensive cost.