High precision comparison between SNS and SIS Josephson voltage standards

Recently, a new Josephson voltage standard based on a 1 V programmable chip provided by the National Institute of Standards and Technology (NIST) was implemented at the Swiss Federal Office of Metrology (OFMET). A comparison with a conventional Josephson voltage standard showed an agreement of (1.4/spl plusmn/3.4)/spl times/10/sup -10/ at 1 V. This result demonstrates the new system is functioning properly and can be used in various types of measurements. In particular, it will be one of the key components of the Watt balance experiment (1999) at OFMET.