The technicians in the cryogenics lab build and maintain the refrigeration systems that cool the electronics inside the vertex room of the antennas. Here Tommy and Michael are working on "cold heads." The coldhead will be installed in a vacuum dewar, and helium gas will be used to cool the system down to about 15ºKelvin, or -432ºFahrenheit.
The technicians must work in a clean environment. In some cases they wear white cotton gloves when handling the components. If oil from their hands gets on the components, it will freeze and act as an (unwanted!) insulator.
Linda uses the Internet to check the specs on one of the pieces of equipment.