Realization of Zinc Fixed Point Cell in NIMT

Abstract: The temperature scale at National Institute of Metrology (Thailand), NIMT, is realized in accordance with the ITS-90 in the temperature range from triple point of mercury (-38.8344oC) up to the freezing point of silver (961.78oC). The sealed type cells are presently used as the national standard. In this paper, the significance of a new set of NIMT fixed point cells, the open type cell, will be discussed. The realization of new zinc freezing point cell had only been compared with the current cell. The temperature difference and the comparison uncertainty were investigated