The Reproduction of the As-Maintained Unit of Voltage at IEN by Means of 2e/h

The IEN participates in the joint venture of the national standardizing laboratories which reproduce the as-maintained unit of voltage by means of the fundamental constant 2e/h. In this paper, the adopted long-life thermally cyclable junctions with Nb-base electrodes are described. Also, the apparatus, procedures, and measurements used to monitor the unit of voltage at IEN during recent years are outlined. The results indicate a small positive drift of about 6 × 10-8 per year for VIEN-69; on January 1, 1980 they gave the relation 2e/h = (483 594.41 ± 0.1) GHz/VIEN-69.