We supply our coolers with the temperature sensors and heaters wired to a micro-D connector fixed on the cooler. (We can send the datasheet for the Glenair connectors we use). A GL7 has a 25-way MDM, and a GL4 has a 21-way MDM. The end user will need to either make or buy the cables to connect this plug to the world outside the cryostat. It is not possible for us to provide that cable, as every user has their own system of wiring into the cryostat. The user will also want to connect wires to their own experiment that they are cooling, and to their GM or PTC as well.
In our system, we have a cryostat cable that terminates at one end in a hermetic (vacuum) 55-way connector that fixes to the outside of the cryostat. There is a loomed ribbon cable that joins the outside connector to an internal 51-way MDM connector that we permanently fix into the inside of our cryostat, on the ‘warm’ side of the 4K plate, inside the 40K radiation shield. The loomed ribbon cable is made of manganin / constantan wires, which have high electrical conductivity, but very low thermal conductance, to minimise the flow of heat from the outside world into the cryostat. This cable was made for us by a specialist cryogenic wiring company – we have one of these fixed on each of our cryostats, it is part of the cryostat, not part of the sorption cooler. It is very important to have the right specification for the cryostat cable as otherwise it will impose a heavy heat load on the experiment.
Then, for each set-up we make an adaptor cable for the internal wiring. This adaptor connects the CRC sorption cooler (plus other sensors) to the fixed cryostat wiring cable. If the CRC sorption cooler has its electrical plug on the ‘warm’ side of the 4K plate, i.e. in the same space as the cryostat cable termination, the adaptor can use copper wires since it is entirely within a single zone of the cryostat. If it needs to pass through into the 4K space then close attention will be needed to the material, length and thermal sinking of the wires. So, if our customer already has a cryostat with a fixed wiring cable installed, they will need to make their own adaptor to connect their cryostat wiring to the CRC cooler. We are happy to advise on wiring if needed.