apparatus for connecting an hv cable to the cathode of an x - ray tube is provided with a housing disposed for attachment to the x - ray tube , and a quantity of epoxy or other electric insulating material contained within the housing . the epoxy serves to insulate the exposed end portions of the hv cable conductors , which extend beyond the cable insulation for insertion into the x - ray tube casing . the connector apparatus further includes a heat transfer device , such as a heat pipe , which extends long the cable within the connector housing . a quantity of working fluid contained in the heat transfer device is disposed for bi - directional movement along the device to transfer heat from a first location within the insulating material to a second location proximate to the housing .