CIPM MRA COMPARISON REPORTS

This comparison was initiated by National Physical Laboratory (NPL, UK) and was designed to compare the realization of the ITS-90 at the freezing point of zinc, 692.677 K (Zn FP) through a) the calibration of two SPRTs and b) independent measurements of a transfer open zinc cell. Each participant was to use two transfer standard SPRTs to measure two Zn fixed point cells, namely their own national standard cell and a transfer standard cell (see Appendix1: Technical Protocol). The primary objective was to link NPL Zn realization to CCT-K9.