I assembled the high quality viewport window (Cat.B) to be installed for TMSY later.

It is now left in a desiccator at the side of the IMC beam tube. See also 7466 for TMSX... and now I find myself mistook the direction of the side arrow (pointing the obliqued surface) when I read 7465, although I thought I checked carefully the obliqued surface with my eyeballes... OMG. But maybe I will go as is. For optical viewpoint, only the thinkness direction does matter but not the facing direction of the wedged surface, while for vacuum sealing, this upside-down of the surface might matter... let's see.

And, even though referred in 4115 as not to do so, today I had used a torque wrench to do the plus (i.e. Phillips) screws by 5Nm. And some of the screw head got stripped... By the way, looking at the photo in 4115, the arrow seems pointing to the air side (this is Cat.C but the same company made Cat.B and C simultaneously...). According to the specification sheet (whichever Cat.B or C), "an arrow on the OD at the thickest point of the wedge pointing to S1", and S1 is not the wedged surface, and S2 has wedge; so the "proper" assembly should be with the arrow point downward... So, from the vacuum viewpoint, we do not need to care according to the leak check done so far???