An x-ray tube includes a housing containing cooling oil and a vacuum envelope disposed within the housing and including a solid envelope wall. The oil is disposed between the housing and wall. An anode and cathode are arranged in a vacuum environment and surrounded by the wall. A rotor connected to the anode is arranged on bearings within the vacuum environment. Additionally, a stator assembly positioned within the oil surrounds the rotor to define an oil-filled annular gap. The stator assembly includes a stator core, stator teeth spaced apart by intervening stator slots, and stator windings disposed within the stator slots. Each stator tooth includes a tooth tip positioned adjacent to the boundary wall and set a distance apart from the stator windings to form an intra-slot cooling channel in fluid communication with the oil-filled annular gap such that the stator teeth inclusive of its tooth tips are immersed in oil.