Abstract：The argon triple-point,one of the required reference fixed points at the low-temperature range in the international temperature scale of 1990 (ITS—90),is significant in the verification of national primary standard.A new type of sealed argon triple-point device,used to calibrate long-stem platinum resistance thermometers（SPRTs）in quasi-adiabatic conditions,is developed by National Institute of Metrology.The software used for automatic measuring and instrument controlling is developed as well.The results show that the plateau time of the new type of sealed argon triple-point device can reach above 23 hours,and the difference of the plateau is within 0.2 mK during 16 hours.The reproducibility is 0.1 mK.The new device successfully eliminates defects of the short plateau time and the great difficulty in the realizing of the argon triple-point with a continuous heat flux method.This research improves the argon triple-point device,and ensures the accuracy of the temperature verification.
［1］Preston-Thomas H.The International Temperature Scale of 1990(ITS—90)［J］.Metrologia,1990,27(2):107-108.
［2］Ancsin J, Phillips J.Argon Triple Point Realization Cryostat for Platinum Resistance Long Stem Thermometers［J］.Review of Scientific Instruments,1976,47(12):1519-1521.
［3］Bloembergen P,Bonnier G,Ronsin H. An International Intercomparison of Argon Triple Calibration Facilities,Accommodating Long-stem Thermometers［J］. Metrologia, 1990, 27(2): 101-106.
［4］Marcarino P,Steur P P M,Dematteis R.Realization at IMGC of the ITS—90 Fixed Points from the Argon Triple Point Upwards［J］.AIP Conference Proceedings,2003,684(1):65-70.
［5］Pavese F,Ancsin J,Astrov D N,et al.An International Intercomparison of Fixed Points by Means of Sealed Cells in the Range 13.81K-90.686K［J］.Metrologia,1984,20(4):127-144.
［6］Ahmed M G, Hermier Y, Moussa M R, et al. Argon Triple-Point Device to Calibrate Long-stem Thermometers in Quasi-adiabatic Conditions［J］.AIP Conference Proceedings,2003,684(1):197-202.
2011, Vol. 32 
