Construction of a gravity-fed circulating liquid nitrogen dewar for experiments in high vacuum

摘要

The construction of a high-vacuum gravity-fed liquid nitrogen dewar is detailed. The dewar allows the liquid nitrogen to be directed to internal parts of the chamber using standard fittings and stainless steel tubing. By using the chamber vacuum as the primary insulation for the dewar, a lifetime in excess of 12 h prior to the need for refilling is found.