An x-ray source includes an enclosing vessel, a first roller arranged at least partially within the enclosing vessel, a second roller arranged at least partially within the enclosing vessel and to be in rolling contact with the first roller, and a drive assembly operatively connected to at least one of the first and second rollers. The drive assembly causes the first and second rollers to rotate while in contact to bring portions of the first and second rollers into and out of contact within the enclosing vessel as the first and second rollers rotate. The first roller has a surface at least partially of a first triboelectric material and the second roller has a surface at least partially of a second triboelectric material, the first triboelectric material having a negative triboelectric potential relative to the second triboelectric material. The enclosing vessel is structured to provide a controlled atmospheric environment, and the first triboelectric material, the second triboelectric material and the controlled atmospheric environment are selected such that rolling contact between the first and second rollers produces x-rays.