| Zugriffsnummer | 27902 |
| Dokumenttyp | Bericht |
| Sprache | Englisch |
| Titel | Supplementary information for the ITS-90: Chapter 4, Interpolating constant-volume gas thermometry |
| Autor(in); Institution |
Steur, P. P. M.; Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, ITALY
Fellmuth, Bernd; 7.4, Temperatur, PTB-Berlin
Tamura, O.; National Metrology Institute of Japan (NMIJ/ AIST), Tsukuba, JAPAN
|
| Quelle/Jahr | Consultative Committee for Thermometry (CCT): Report of the 26th meeting (May 2012) to the International Committee for Weights and Measures:(2012), 9 S. |
| URL | |
| Berichtsnummer | CCT/12-05 |
| Konferenzangaben | 26rd CCT Meeting, Paris, 04-05, May, 2012, Frankreich |
| Zusammenfassung | In the range 3 K to the triple point of neon (~ 24.6 K), the ITS-90 is defined in terms of a 3He or 4He constant-volume gas thermometer, CVGT, calibrated at three temperatures. Background information on absolute constant-volume gas thermometry can be found in the reports of four modern gas thermometry experiments [Berry 1979, Steur and Durieux 1986, Kemp et al. 1986/87 and Astrov et al. 1989], which provide details of current good practice, and form the basis for the numerical values assigned to the low-temperature portions of ITS-90. These experiments demonstrate in different ways the very great care required in apparatus design and data analysis when a helium gas thermometer is used to determine thermodynamic temperatures in terms of a single reference temperature. Measurement difficulties can be reduced to trivial levels, however, if the single reference temperature is replaced by two or three designated calibration temperatures, provided that these calibration temperatures lie within the measurement range, and that the measurement range itself be not overly wide. These requirements are met in the case of the ITS-90 gas thermometer: with appropriate design and choice of gas density (the criteria are not too restrictive), measurements accurate to the order of 0.2 mK are not difficult to obtain. |
