| 摘要 |
PROBLEM TO BE SOLVED: To provide an X-ray tube device in which the size of focus electrode need not be large and the focal size can be changed while the focal profile is made not to be changed for any focal size. SOLUTION: The three electrodes 13-15 insulation-fixed at the bottom of a groove 12 of an insulating block 11 have an analogous outline and are arranged in concentric form and are formed with a group of carbon nanotubes on the front surface and a gate 16 is arranged in front of these. A focus electrode 17 having a groove (hollow part) corresponding to the groove 12 is installed on the insulating block 11. Negative potential is selectively given to the electrodes 13-15 by switches 21-23 and electrons are emitted from the electrodes turned into negative to the gate 16, and passing through the gate 16 and focused by the focus electrode 17, proceed to the anode. Since the outline of the electrodes 13-15 is made analogous, only the size of electron emission face is different, and emission face is maintained in the analogous shape, and the X-ray focus is similarly maintained in analogous shape and only the size is different. COPYRIGHT: (C)2006,JPO&NCIPI
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