X-ray generating device

摘要

An X-ray generating device comprises a focal electrode ( 10 ) placed adjacent to the cathode ( 9 ) and provided with a focal aperture ( 10 a) aligning with the cathode. A positive voltage is applied to the focal electrode relative to the cathode so that equipotential lines around the focal aperture may bulge toward the X-ray target ( 2 ). Thereby, the part of the electron beam having a large diverging angle is captured by the focal electrode, and only the part of the electron beam having a uniform diverging angle is allowed to pass through the focal aperture so that the electron beam can be favorably micro focused upon the X-ray target and can be given with a high intensity.