Stabilization of magnet current using Josephson voltage standard

A feedback method is suggested, allowing the stabilization of a high current source by using the programmable Josephson voltage standard (PJVS) voltage reference. It is demonstrated that a current of 0.1 A from a calibrator with an inherent stability of 10⁵ A/A to 10⁶ A/A can be stabilized within a standard deviation of 2×10⁸ A/A. The advantage of the feedback method is that in principle, any high current can be stabilized effectively if the appropriate current sensing resistors are available. The compliance voltage of the stabilized current to the load depends only on the compliance voltage of the main current source and of the voltage-to-current converter, regardless of the output level of the PJVS array.