Comparison of the realizations of the ITS-90 at the freezing points of Al(660,323 °C) and Ag (961,78 °C)

Project Description

The comparison will be to EUROMET Key comparison No. 4 for the field of thermometry and follows basically the ideas of CCT K4. The aim is a comparison of the realisation of Al and Ag freezing points of 20 EUROMET members. Some of them will participate only for the Al freezing point.

The comparison is organised in 4 loops. In each loop there will besides the pilot laboratory PTB another NMI which has already participated in CCT K4 or CCT K3 (for the Al freezing point), acting as subpilots. These laboratories are BNM/INM, IMGC, NPL and SMU. EUROMET-T K4 will be linked to CCT K4 using the measurements of the pilot and the subpilots.

Contrary to CCT K4, EUROMET-T K4 will be a comparison of thermometers and not of fixed point cells. For additional information on the stability of the thermometers in each loopn a SPRT for measurement at the Al freezing point and 2 HTSPRTs for measurements at the Ag freezing point will be calibrated by all participants.

Final Report 2008-04-23

The comparison is completed and the results are available in the KCDB.