A versatile 2 MeV, 200 mA compact X-band linac

A small, high performance electron linear accelerator is described. It is a modified version of a commercially available portable X-ray source. The fixed power supplies were replaced with remote controllable supplies allowing a systematic exploration the linac´s parameter space. A condition in which the linac performs nearly in accordance with its theoretical limits was found. The 9.3 GHz RF linac and beamline deliver a 2 nsec train of approximately 10 psec pulses with a peak current, limited by beam loading of the RF structure, of more than 200 mA and a beam energy of around 2 MeV with a 5% FWHM energy spread. The small energy spread is due largely to the focusing of the beam through a 500 μm lead pinhole early in the beamline. A 6 μm Mylar vacuum window covers the pinhole allowing the use of the beam in a rough vacuum environment with minimal degradation of the beam emittance. The unnormalized beam emittance is 6 π mm-mrad and the final spot size is 260 μm diameter for f/20 focusing