Special Problems When Realising the Triple Point of Hydrogen as a Defining Fixed Point of the ITS-90
B Fellmuth, D I. Head, F Pavese, A Szmyrka-Grzebyk, Weston L. Tew
The two special problems, which appear when realising the triple point of hydrogen as a temperature fixed point due to the influences of the deuterium content and the catalyst, have been investigated by filling a large number of sealed triple-point cells. The cells differ with respect to the deuterium content (29 mmol D/mol H to 155 mmol D/mol H), type of catalyst (hydrous ferric oxide and gadolinium oxide), catalyst-to-liquid volume ratio (a few per cent to more than 100 per cent) and cell design. At higher catalyst-to-liquid volume ratios, the shape of the melting curve depends on the type of the catalyst, but only the melting temperature of that sample part being in direct contact with the catalyst and thus distorted is changed. The slope of the dependence of the triple-point temperature on the deuterium content has been found to be (5.2 0.4) mK per mmol D/mol H.
International Sympoisum on Temperature and Thermal Measurements in Industry and Science | 8th | | VDE
deuterium, ferric hydroxide, gadolinium oxide, hydrogen, ITS-90, ortho-para conversion, sealed triple point cell, temperature, triple point
, Head, D.
, Pavese, F.
, Szmyrka-Grzebyk, A.
and Tew, W.
Special Problems When Realising the Triple Point of Hydrogen as a Defining Fixed Point of the ITS-90, International Sympoisum on Temperature and Thermal Measurements in Industry and Science | 8th | | VDE, Berlin, 1, GE, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=830758
(Accessed December 10, 2023)