Investigation into the Liner Stabilizer for the Oxford Injector

A mathematical analysis is presented of a combined liner and spray charge control system for regulating the voltage of the single ended Van de Graaff which forms the injector of the Oxford coupled Electrostatic Generators. The stabilizer design, based on this analysis, incorporates automatic switch-over to an auxiliary generating voltmeter stabilizer loop. An automatic gain control in the slit amplifiers eliminates the necessity for manual gain adjustments in most operating conditions. The voltage stability achieved in operation gave a beam energy stability of ± 7 parts in 105 i.e. 4.447 ± 0.000325 MeV measured using the resonance in the reaction 15N(¿, ¿)19F. Repeated voltage breakdowns of the HT terminal were prevented by a protection circuit based on the analysis of the breakdown behaviour of the generator. The calculated performance of the circuit has been verified by the observed behaviour after total breakdown.