Development of an intense pulsed relativistic electron beam of large diameter and uniform flux

Experiments were carried out on a 4 MV pulsed electron-beam generator of nu / gamma approximately=1, in order to obtain a broad, uniform flux distribution for sample irradiations. Various cathodes were tested, and a design using multiple razor-blade emitters was chosen for its uniform emission and small electron angles. The flux of the propagated beam was measured as a function of both radial and axial distance in the irradiation drift tube. Small electron angles and the relatively uniform flux distribution of the injected beam resulted in propagation with a slow change of radial flux profile as a function of axial drift distance. Between the positions of maximum convergence the irradiation flux passed through regions with a fairly uniform flux of 40 cal cm-2 over a diameter of 100 mm.