Receiver Module

The receiver insert is designed as a plug-in unit inserted from the top of the cryostat. It is constructed in 3 sections, separated by stand-offs made of glass-fiber tubes. The room temperature part is a circular plug made of aluminum, with its center bored out for the vacuum signal window. The 80K stage is mainly a lens holder, and it makes contact with the 80 K radiation shield via a ring of BeCu spring fingers. The 4K stage is connected to the cold head through flexible pure copper straps. On the 4K stage are the SIS mixer block, followed by an isolator, and a HEMT amplifier. The HEMT operates at 5 GHz with a 2 GHz bandwidth. The IF is further amplified and filtered at the 20 K stage of the cryostat before exiting the dewar.

This photo is a real receiver insert for 178 -250 GHz channel, shown in an up-side-down sense.