The first picture shows the inside of the cryostat, with the ADR in the foreground and the sorption fridge behind it.  The WaFIRS module is shown in the middle of the cryostat, mounted to the 300mK radiation shield.  The circular hole in the shield corresponds to the dewar window, where the light from the telescope enters the spectometer.

The corrugated feedhorn (shown at right) couples the light to a rectangular waveguide which then feeds it into the parallel plates.

The various temperature stages in the dewar are thermally isolated using Kevlar isolation posts.  The posts are made of 2 pieces of aluminum held together with Kevlar yarn and tensioned with belleville spring washers. The picture on the right shows the posts supporting the grating module, and the picture on the left shows 4 Kelvin bench, before the 300 mK box is mounted to the posts shown.