On the energy distribution of a spiraling electron beam

A retarding-field analyzer was used to investigate the energy conversion and the energy spread of a spiraling electron beam, where the trajectory is generated from a magnetic-corkscrew/magnetic-ramp combination. It was found that in the absence of space-charge effects, the corkscrew will generate a near-rectangular transverse energy distribution from a monoenergetic rectilinear-flow beam. The width of this distribution is independent of the degree of energy conversion but proportional to the beam voltage. The magnetic ramp amplifies both the mean transverse energy and the energy spread linearly.