Patent ID: 7260181

Claim:
An x-ray tube comprising: an anode defining a target; a cathode in operative relationship with the anode to produce x-rays; an evacuated envelope enclosing the anode and cathode, the evacuated envelope including a metal frame portion, the metal frame portion having a metal frame portion backscatter coefficient; an x-ray transmissive window joined in a vacuum tight manner to the metal frame portion of the evacuated envelope, the x-ray transmissive window having a window material backscatter coefficient; and a backscatter layer deposited on both (i) an inner vacuum surface of the x-ray transmissive window including a region of the x-ray transmissive window corresponding to a path for desired x-rays to exit through and (ii) an inner vacuum surface of the metal frame portion of the evacuated envelope around the x-ray transmissive window, the backscatter layer having a backscatter coefficient greater than the backscatter coefficient of both of the x-ray transmissive window and the metal frame, and the backscatter layer further being configured to re-direct backscattered electrons generated during x-ray generation to not be absorbed within (i) the x-ray transmissive window or (ii) the metal frame portion of the evacuated envelope around the x-ray transmissive window.