Ultrastable Voltage Source to 10 kV Using Capacitive Feedback

A unique system has been developed with the capability for use as a voltage monitor or regulated voltage source to a stability level as good as 1 ppm/12 h, or 0.1 ppm/15 min. The system employs a precision capacitor charged to a voltage level matching the level of interest, so that it provides optimum discrimination against amplifier noise and also obviates the need for a voltage divider. A useful voltage range from 1 kV to 10 kV has been demonstrated and there is reason to hope that the technique can be applied at higher voltage levels. The short term stability, for time intervals of 1 hour or less, is superior to that obtainable from a conventional system containing the usual voltage reference, voltage divider, and dc amplifier.