SRM 1970: succinonitrile triple-point standard - a temperature reference standard near 58.08 degrees C
Billy W. Mangum, Samir El-Sabban · Journal of Research of the National Bureau of Standards · 1985
Triple-point-of succinonitrile cells have been tested and established as Standard Reference Material (SRM) 1970.Of the 115 cells tested, 109 were accepted as SRM 1970.Five of the 115 cells had triple-point temperatures lower than 58.0785 'C (the low-temperature limit established for SRM 1970) and, consequently, were rejected.One of the 115 cells broke during tests on it.The mean value of the triple-point temperatures (obtained by freezing) of the 109 cells is 58.0796±0.0015'C, where the uncertainty is the total estimated uncertainty relative to the International Practical Temperature Scale of 1968, Amended Edition of 1975.The standard deviation of the triple-point temperatures is 0.48 mK.The purity of the succinonitrile of the SRM 1970 cells is estimated to range from 99.999,97% to 99.999,84%.The preparation of the cells, the various tests performed on them, and the procedure recommended for their use are described.