Crossed-field beam tester

Design, construction and operation of a beam tester for measurement of electron beams in crossed-field electron tubes is described. A small jet of gas, preferable helium, is injected into the interaction space of simulated injected Beam Crossed-Field Amplifiers of real size. The interaction of the gas molecules with the electrons of the injected electron beam results in the release of far ultraviolet photons which are collected and counted by means of a solar blind photon detector. The mechanical and optical design of the beam tester allows the determination of electron distribution within the interaction space with a resolution as small as 20 × 20 × 25 µm³.