New half voltage and double pulse operation of the HERMES III linear induction accelerator

The standard operating mode produces bremsstrahlung with an endpoint energy of about 18 MeV. This paper describes a new mode with a 8.5 MeV endpoint energy and the same standard mode pulse characteristics achieved by operating only half of the accelerator at full charge with the advantage of minimal setup time. An extension of the new half voltage mode is to use the other half of the accelerator for delivering a second pulse at a later time using the same technique. This double pulse mode is ideal for beam generation which requires a long interpulse time in the millisecond regime. The beam characteristics of the two half voltage pulses are nearly identical with the nominal radiation pulse full width at half maximum of 21 ns and 10-90% risetime of 11 ns.