Comparison of Conventional L and S-Band Electron Linacs as Pion Sources Suitable for Radiotherapy

A discussion on target configuration and negative pion yield, supported by high power electron beam experimental data, establishes 250-330 kW at 500 MeV to be desirable beam parameters for an electron linac which, in combination with a Stanford carrousel type pion spectrometer, would provide a practical source of ¿- mesons suitable for radiotherapy applications. A preliminary analysis confirms that peak current limitations imposed by cumulative beam breakup may be avoided by adopting specific microwave design procedures, which minimize higher order mode transverse shunt impedances in potentially troublesome zones of individual waveguides, and which introduce higher order mode stop bands at specific locations along the beam centerline, similar to the techniques used for the MIT and IKO high duty factor linacs.