Portable Solid Nitrogen Cooling System for High Transition Temperature Superconductive Electronics

In this work we present a miniature solid nitrogen cooling system designed for 45 K operation of (high-TC) superconductor Josephson devices. The system utilizes a small 100mL fiberglass Dewar and external pump to solidify nitrogen in thermal contact with a circuit board insert. Cooling tests reveal that the system holds at its base temperature of 45 K for over 12 hours. This can provide a low power, low weight system for ultra-portable superconductive electronics and other cryogenic sensors.