Effect of surrounding metallic walls on the floating potential of the target under electron-beam irradiation in medium vacuum

We present experimental results and numerical estimates that witness to the possibility of controlling the floating potential of an insulated metal target being irradiated by a continuous electron beam in medium vacuum by means of applying a dc bias on the metal cylindrical wall surrounding the beam and the target. This dependence extends a possibility to control the surface potential of a dielectric subject to electron beam treatment under the same conditions. •Electron-beam irradiated target potential was set by the biased walls around beam.•Walls bias also controls the sheath between beam plasma and walls and target.•Method can be used to control the potential on e-beam irradiating dielectric target.