THE IMPROVEMENT OF THE OUTPUT PERFORMANCE OF A LOW-ENERGY MEDICAL STANDING-WAVE ACCELERATOR

An important objective in the operation of low energy medical standing wave linear accelerators for medical X-ray use, is to limit the sprea d of energies into the low energy region in order to reduce skin dose to a minimum. This article suggests how this might be achieved by adju stment of the timing of the electron beam pulse relative to the rf pow er pulse. A theoretical model of a tube based on equivalent circuits i s examined to support this proposal. In addition, parameters which aff ect the dose rate are optimized, in particular the beam loading, and t he coupling constant between the accelerator tube and the rf power sou rce.