A Highly Stable 150 KV Supply

Abstract

A high voltage power supply has been constructed for use with the ORNL Superconducting Microscope described elsewhere in these proceedings. A simplified schematic diagram of the system is shown in Figure 1. The regulator circuit employs a “bouncer” with a cathode-follower output. This configuration results in a low output impedance and the bouncer can thus drive a load capacitance over a wider bandwidth than the conventional common-cathode circuit. The voltage divider for the regulator is a dual unit originally developed to determine the stability of resistive high-voltage dividers. A dual capacitive divider is an integral part of the voltage divider as shown in Figure 1. The dual units have proven to be very useful in practice since one divider may be used in the regulator while the second is used to monitor the noise present on the high voltage. Mercury cells are used as reference elements in the regulator. Wide-band noise on the output is about one ppm at present. Modifications are now under way to eliminate at least two of the known sources of noise in the system.