X-RAY TUBE

PROBLEM TO BE SOLVED: To provide an X-ray tube having a new structure used for medical, industrial and analytic applications. SOLUTION: This X-ray tube is provided, in a vacuum tube 11, with: a positive electrode 12 having a conical shape having a tip side 12a extended onto an X-ray radiation direction line L1 with a conical top part 12a1 thereof located on the X-ray radiation direction line L1; a field emission type annular negative electrode 14 annularly surrounding the radial outside of the positive electrode tip part 12a coaxially with the positive electrode tip part 12a, and having an outer peripheral surface formed of a nano-carbon film; and an electron screening member 16 arranged on both sides of the annular negative electrode 14 in the X-ray radiation direction, and screening electrons emitted by the annular negative electrode 14; and is structured such that an X-ray extraction window 11a formed of an X-ray-permeable thin film is arranged on a tube wall of the vacuum tube in front of the positive electrode tip part 12a on the X-ray radiation direction line L1. COPYRIGHT: (C)2009,JPO&INPIT