A Determination of Thermodynamic Temperatures and Measurements of the Second Virial Coefficient of⁴He Between 13.81 K and 287 K Using a Constant-Volume Gas Thermometer

Abstract

The construction of a constant-volume gas thermometer for use between 10 K and 300 K is described. The thermometer features gas-flow temperature control and the capability for continuous operation. Relative PV isotherms giving values for thermodynamic temperature and the second virial coefficient for 4He were measured at 27 K, 43 K, 54 K, 63 K and 84 K referenced to 20 K on NPL-75 and at 172 K referenced to 273.15 K. Further measurements at the isotherm temperatures referenced to 273.15 K were used to redetermine the reference temperature at 20 K. Constant-volume gas-thermometry measurements were carried out at 72 temperatures between 13.81 K to 287 K. The results agree well with NPL-75 from 13.81 K to 27.1 K but differ from IPTS-68 significantly from 27.1 K to 273.15 K.

Progress towards the determination of thermodynamic temperature with ultra-low uncertainty

“…Particularly, the mutual consistency of various AGT data at T Ga is indeed striking, considering that these data were obtained with rather different, weakly correlated experiments [52], and motivates the further development of AGT at a higher temperature range. that the magnitude of the differences (T − T 90 ) have a smaller (less negative) magnitude than previously determined by AGT [13,17], in slightly better agreement with the CVGT data of Kemp et al [53] than with those of Astrov et al [54]. Most importantly, the outstanding progress achieved by the AGT method during the last few years is well illustrated by the visual comparison of the uncertainty of the WG4 interpolation (shaded area in figure 4) with the much smaller uncertainty associated with the dense NPL dataset.…”

Ab initiopotential energy curve for the helium atom pair and thermophysical properties of the dilute helium gas. II. Thermophysical standard values for low-density helium

“…In this connection we refer to Figure 2 of the paper by Hurly and Moldover [1] who obtained the same results for their potential in the temperature range 10-10,000 K. [30] agree at the higher temperatures with the second virial coefficients determined by Blancett et al [33] and by Holste et al [37]. Above room temperature the data by Schneider et al [31,32], Waxman [34], and Kell et al [36] are in close agreement up to about 500 K.…”

Review of temperature measurement

“…6-12͒. Examples of the utilization of constant volume gas thermometry are reported by Guildner and Edsinger, 7 by Berry, 9 Kemp et al 10 and in Refs. [13][14][15][16].…”