At the National Metrology Institute of Japan (NMIJ), the triple points of 20Ne and 22Ne were realized using modular sealed cells, manufactured by the Istituto Nazionale di Ricerca Metrologica (INRiM) in Italy to measure the difference of the triple-point temperatures of 20Ne and 22Ne. Standard platinum resistance thermometers (SPRTs) were used that were calibrated by NMIJ on the International Temperature Scale of 1990 (ITS-90). In previous reports, sealed cells of 20Ne and 22Ne were mounted one at a time in a cryostat and their triple points were realized in separate cool-downs (the single-cell measurement). In this study, first, the triple point was realized using the single-cell measurement for 20Ne and 22Ne cells. Second, the 20Ne and 22Ne cells were mounted together on the same copper block and their triple points were realized subsequently one after the other in the same cool-down of the cryostat (the double-cell measurement). The melting curves observed by the single-cell and the double-cell measurements were almost identical for each cell. The difference of the triple-point temperatures between the two cells, 22T −20 T , was estimated, not only using the subrange of SPRTs defined in the ITS-90 from 13.8033 K to 273.16 K (subrange 1) but also that defined from 24.5561 K to 273.16 K (subrange 2). The difference in (22T −20T ) between the subranges 1 and 2 is within 0.06 mK, which is caused by the subrange inconsistency in the ITS-90. The standard uncertainty in (22T −20 T ) due to the subrange inconsistency is estimated to be 0.017 mK. After correction for the effects of impurities and other isotopes in the 20Ne and 22Ne cells, the difference in the triple-point temperatures between pure 20Ne and pure 22Ne is estimated to be 0.146 64 (5) K on subrange 1, which is consistent within the uncertainty with the former studies. When 22T −20T for pure 20Ne and pure 22Ne is estimated on subrange 2, 22T −20T becomes 0.146 60 (5), which agrees very well with the former reports of INRiM evaluating 22T −20T on subrange 2.
Study on the Difference of the Triple Point Temperatures of 20Ne and 22Ne using Sealed Cells / Nakano, T.; Tamura, O.; Steur, PETRUS PAULUS MARI; Pavese, F.. - In: INTERNATIONAL JOURNAL OF THERMOPHYSICS. - ISSN 0195-928X. - 35:6-7(2014), pp. 1032-1043.
Study on the Difference of the Triple Point Temperatures of 20Ne and 22Ne using Sealed Cells
STEUR, PETRUS PAULUS MARI;
2014
Abstract
At the National Metrology Institute of Japan (NMIJ), the triple points of 20Ne and 22Ne were realized using modular sealed cells, manufactured by the Istituto Nazionale di Ricerca Metrologica (INRiM) in Italy to measure the difference of the triple-point temperatures of 20Ne and 22Ne. Standard platinum resistance thermometers (SPRTs) were used that were calibrated by NMIJ on the International Temperature Scale of 1990 (ITS-90). In previous reports, sealed cells of 20Ne and 22Ne were mounted one at a time in a cryostat and their triple points were realized in separate cool-downs (the single-cell measurement). In this study, first, the triple point was realized using the single-cell measurement for 20Ne and 22Ne cells. Second, the 20Ne and 22Ne cells were mounted together on the same copper block and their triple points were realized subsequently one after the other in the same cool-down of the cryostat (the double-cell measurement). The melting curves observed by the single-cell and the double-cell measurements were almost identical for each cell. The difference of the triple-point temperatures between the two cells, 22T −20 T , was estimated, not only using the subrange of SPRTs defined in the ITS-90 from 13.8033 K to 273.16 K (subrange 1) but also that defined from 24.5561 K to 273.16 K (subrange 2). The difference in (22T −20T ) between the subranges 1 and 2 is within 0.06 mK, which is caused by the subrange inconsistency in the ITS-90. The standard uncertainty in (22T −20 T ) due to the subrange inconsistency is estimated to be 0.017 mK. After correction for the effects of impurities and other isotopes in the 20Ne and 22Ne cells, the difference in the triple-point temperatures between pure 20Ne and pure 22Ne is estimated to be 0.146 64 (5) K on subrange 1, which is consistent within the uncertainty with the former studies. When 22T −20T for pure 20Ne and pure 22Ne is estimated on subrange 2, 22T −20T becomes 0.146 60 (5), which agrees very well with the former reports of INRiM evaluating 22T −20T on subrange 2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
