High-Purity Metal Fixed Point Cells

These cells were jointly developed with National Institute of Advance Science and Technology (AIST/NMIJ) to realize the defining points of ITS-90. Cells are designed specifically to realize the liquid-solid equilibrium of certain high-purity metal elements. Cells are available as sealed or open cells. All cells contain the high-purity thermometric metals in graphite crucibles, surrounded by an envelope of pure fused quartz. Sealed cells are completely enclosed in quartz and filled with an argon gas, which assumes a pressure of one standard pressure (101325 Pa) at the freeze point. Sealed cells are consequently protected against contamination and the influence of ambient pressure, and are easy to handle, as there is no need to prepare an inert gas supply-exhaust system. A series of Model 37000 are sealed cells, and can be used for the calibration of SPRTs.