The TCS viewports were installed on BSCs 1 and 3 today. The gap on the optic enclosure for the primary optics was between .030" and .040" on both viewports. So the new Kapton shims created a good gap for pulldown onto the Viton. They were proofed and leak tested Wednesday and Thursday. There was a small issue with the proofing as the Kapton wedge on top of the primary optics doesn't seal (nor is it expected to). So although the pressure for proofing (15.5 psi) was reached it would not hold. This was determined not to be an issue. The leak test went without incident, Helium flow was 1 LPM and each optic was targeted for ~30 seconds and the enclosure was targeted for ~1 - 1.5 minutes. No leaks were seen, calibration using internal leak showed 1.0e-7 torr L/s with a stated value of 9.8e-8 torr L/s.

The viewports replaced the blanks on the chambers today. Kyle noted the gap pre-torquing of the bolts was low and the gap was found to be 0.02". Lower than is normally sought (>0.025"). This seems to be from a deeper recessed knife edge on the viewport. John gave the okay to torque the viewports down and continue. They are now metal to metal on the flange.