An x-ray tube includes a vacuum enclosure, a shaft having a first end and a second end, a flange attached to the first end of the shaft, the flange having an outer perimeter, and a ferrofluid seal assembly having an inner bore, the inner bore having an outer perimeter smaller than the outer perimeter of the flange. The shaft is inserted through the bore of the ferrofluid seal assembly such that the ferrofluid seal assembly is positioned between the first end of the shaft and the second end of the shaft and such that the first end extends into the vacuum enclosure, and the ferrofluid seal is configured to fluidically seal the vacuum enclosure from an environment into which the second end of the shaft extends.