PURPOSE: To generate X-ray having the desired ray quality without enlarging a device by providing multiple different ring-shape focus surfaces on a target basic material, and selecting the focus surface in response to the use of photographing.
CONSTITUTION: Two kinds of doughnut-shape focus surfaces 1, 2 are bonded on a target basic material 3. An anode provided with a target and a part for supporting multiple cathodes are sealed inside of a vacuum case 6. Cathodes 4, 5 are provided opposite to the focus surfaces 1, 2. Electron beam from the cathodes 4, 5 collides with the focus surfaces 1, 2 to generate X-ray. At this stage, the X-ray having the ray quality corresponding to the material of the focus surfaces 1, 2 can be generated. The X-ray having the desired ray quality can be obtained by providing a filter corresponding to each cathode and the material of the focus surfaces. furthermore, a shallow groove is provided in a part to be bonded, and since the focus surface 1 is fitted therein, contrast and image quality is improved without enlarging a device.
DAN YOSHIHIKO
KIZUYA MINORU
HITACHI DEVICE ENG