Abstract: An apparatus for the treatment of a sample in a vacuum enclosure having a wall on which a vacuum-tight feedthrough is mounted; the sample being supported on an elongate hollow rotor rotatable about an axis and disposed within the vacuum enclosure, the sample having a front face which is to be treated and also having a rear face; energy conducting means passing from the feedthrough towards the rear face of the sample through the rotor; inner magnet field generator(s) affixed to the rotor; outer magnet field generator(s) mounted to rotate outside of the vacuum enclosure about the axis, the outer magnetic field generator(s) being magnetically coupled to the inner magnet field generator(s), and thereby capable of causing the inner magnet field generator(s) and the rotor to rotate about their common axis; and a source for directing material or radiation at the front face.