Electron Linear Accelerator Structures and Design for Radiation Therapy Machines

Requirements for straight- and bent-beam medical accelerator configurations are compared. Technical progress of straight-beam accelerators over the past 12 years is reviewed and the trade-off between optimized shunt impedance and maximum accelerating gradient in structure design is examined. Relative advantages of side-coupled and interlaced structures are delineated in the light of much higher permissible internal electric fields, recently demonstrated. A novel concept for a single-section standing-wave structure with multiple photon mode capability is presented.