Patent ID: 7218703

Claim:
An X-ray microscopic inspection apparatus having X-ray generating means for generating an X-ray by allowing an electron beam from an electron source to impinge on a target for X-ray generation, for inspecting an object by utilizing said X-ray, said X-ray microscopic inspection apparatus comprising: a field emission electron gun having an ultra-high vacuum electron gun chamber, an anode and an electron generating portion, wherein the electron generating portion is adapted to generate electrons and said anode is adapted to generate an electric field to accelerate said electrons; said field emission electron gun further comprising a magnetic superposition lens including a magnetic circuit and a magnetic field generating portion, wherein said magnetic field generating portion is disposed separately from said ultra-high vacuum electron gun chamber and said magnetic superposition lens is adapted to generate a magnetic field, wherein said electron generating portion is disposed in said magnetic field and said magnetic field is superposed to said electric field thereby reducing the loss amount of said electron beams from said electron source by focusing the accelerated electrons prior to being impinged on said target for X-ray generation.