During operation of a reflection target x-ray source, heat must be removed from many components. The electron beam must be steered to the target and may interact with structures along this path. There is also heat generated in the target itself. This can be excessive, since only a very small percentage of the electron beam's energy is transformed into x-rays. Finally, the x-rays must exit the vacuum through the window, which can also be heated both by the x-rays, reflected electrons, and radiant heat from the target. A water cooled reflective x-ray source provides for water or other fluid cooling of the centering aperture, x-ray target, and/or exit window.