The first of its kind, Pond Engineering's integrated Argon Triple Point cell and maintenance system allows users to realize this ITS-90 Fixed Point according to NIST Technical Note 1265 for cryogenic fixed points with an uncertainty better than 0.35 mK when used with quartz envelope long stem or capsule Standard Platinum Resistance Thermometer (SPRTs).
The self-contained system incorporates an internal storage dewar which holds approximately 2.5 L of liquid nitrogen. Once cooled and frozen, the volume of liquid nitrogen in the internal storage dewar is sufficient to realize the triple point and maintain the cell on plateau for several hours. To calibrate multiple thermometers on a single plateau or to extend the plateau, users simply add liquid nitrogen to the internal storage dewar.