Enomoto, Akutsu

Assembled a category C window (the dimension is the same as shown here) to an viewport adaptor, and installed the assembled viewport window to the SR2 chamber for treating POS and GreenY beams. On the surface of the flange, the thickest side of the window glass is indicated by a marker pen, which is in the direction of minus Y (Fig 5 and 6) of the whole interferometer's coordinate.

As indicated here, an arrow at the outer diameter of the window points the S1 (non-wedged side) and the position is the thickest (Fig 2, 3, 4). Note that the wedged side (S2) should face air (out) side in the adaptor.

When it was installed, the direction of the thickest side is, just determined by me, so that the output beam (POS) can be separated from its ghost beams... hopefully. Note that the IR beam would come from +Y direction to the viewport.

The memo of the viewports is wiki-ed here.