Trilateral comparison in fixed points of Zn, SN, In, Ga and Hg

Project Description

In the 2002 there was a comparison of EUROMET project No. 552. Because it is already 5 years, it is good to have the possibility to trace the stability of SPRT in fixed points of Zn, Sn, In, Ga and Hg.
In the CMI laboratory there will be initial measurement of thermometer Pt 25 (Tinsley) in these fixed points.
The same measurement will be done in PTB and SMU and after returning of SPRT again in CMI.

Final Report 2010-12-27

The subject of the project was the intercomparison of Pt25 thermometer Tinsley calibrated in all laboratories in fixed points of  Zn, Sn, In, Ga and Hg.

CMI was stabilized two Pt25 thermometers and selected one for comparison. After that the measurements were done. The results between CMI and PTB  are within the laboratory specifications with differences -0.43 mK, 0.01  mK, 0.14 mK, -1.24 mK and -0.29 mK for Zn, Sn, In, Ga and Hg, respectively.

After that the same measurements were done with SMU. The thermometer drifted, so CMI prepared another thermometer. The results between CMI and SMU  are within the laboratory specifications with differences 0.69 mK, 0.28  mK and 0.15 mK and 0.42 mK for Zn, Sn, In, Ga and Hg, respectively.