radiometer platform layout

Here is the layout of the Radiometer main platform. The signal beam shown is for the B-channel (around 563GHz). Coming from the subreflector (not shown) it reflects off the tertiary mirror and then through various optical components and the diplexer where side-band rejection occurs. The chopper is used to switch the beam from source to hot load calibration such that when channel A is calibrating, B and C (119GHz) are on source.