Generating Voltmeter -- This is a windmill type instrument that mechanically chops the electric field to generate
a signal exactly proportional to the accelerator's terminal voltage. This is a critical system responsible for
precisely controlling electron beam energy.
2 MV Accelerator
[gif 90K][png 82k][jpeg 19K] photo - 17-Aug-95
The accuracy of the GVM's measurement will eventually set limits on single frequency lasing stability. Therefore,
an entirely new system was designed and built with the goal of <100 parts-per-million accuracy and wide bandwidth.
A precision 4 blade chopper is driven at 10,000 RPM by a regulated brushless servo motor. The signal is integrated
and demodulated in such a way that phase and frequency noise are cancelled.