Open AccessThe International Practical Temperature Scale of 1968 in the region 90.188 K to 903.89 K as maintained at the National Bureau of Standards
Author(s) -
George T. Furukawa,
John L. Riddle,
William R. Bigge
Publication year - 1976
Publication title -
journal of research of the national bureau of standards. section a. physics and chemistry
Language(s) - English
Resource type - Journals
eISSN - 2376-5704
pISSN - 0022-4332
DOI - 10.6028/jres.080a.053
Subject(s) - reproducibility , international temperature scale of 1990 , tin , boiling point , resistance thermometer , freezing point , calibration , triple point , zinc , platinum , analytical chemistry (journal) , scale of temperature , materials science , chemistry , mathematics , metallurgy , temperature measurement , physics , statistics , thermodynamics , environmental chemistry , biochemistry , catalysis
The reproducibility of the International Practical Temperature Scale of 1968 (IPTS-68) in the region 90.188 K to 903.89 K as maintained at the National Bureau of Standards is discussed. The realizations of the triple point of water, the freezing points of zinc and tin, and the boiling point of oxygen are described. The average of the standard deviations of the resistance measurements at the triple point of water of 213 platinum resistance thermometers received for calibration over a two-year period corresponds to ±0.15 mK. The standard deviations of the resistance ratio R ( T )/ R (0°C) obtained with check thermometers employed for monitoring the zinc, tin, and oxygen point measurements correspond to ±0.28 mK, ±0.30 mK, and ±0.16 mK, respectively; the results of repeated calibrations with five thermometers show comparable reproducibility at the tin and oxygen points but the reproducibility is worse by a factor of two at the zinc point. When suitably packed for protection from possible mechanical shock platinum resistance thermometers can be shipped by common carrier and retain their calibrations.