INNOVATIONS IN THERMAL METROLOGY -IMPROVEMENTS AT THE COPPER POINT

摘要

At NCSLi 2009, a new and novel combination of fixed point cell, heat siphon, and immersion compensator was described that is suitable for indium, tin, zinc, or aluminum. Research has continued to try and extend the concept to other ITS-90 fixed points, in particular, silver and copper. In developing a solution to these two higher temperature fixed points (silver melts at 961.78℃ and copper at W84.62℃), solutions were sought that did not involve the use of quartz glass which is both fragile and porous at these temperatures. In order to accurately measure the copper point, a new and novel thermometer was designed and produced. This report presents results obtained with the metal clad cells and as an aside describes the performance of the new very high temperature thermometers.