| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To control the amount of movement of a focus caused by a temperature rise of a positive electrode of a microfocus X-ray tube. <P>SOLUTION: This X-ray tube 10 is provided with two negative electrodes comprising a negative electrode 12 forming a microfocus 32 and an emission negative electrode 13 used only to heat the positive electrode 14, two targets comprising a first target 18 and a second target 19 in positions in the positive electrode 14 facing the two negative electrodes 12, 13. The focus 33 formed of the emission negative electrode 13 in the second target is larger than the microfocus 32. An X-ray tube current larger than that of the conventional microfocus X-ray tube is applied by sharing the emission negative electrode 13 capable of generating a large emission cathode current and the microfocus negative electrode 12 to control the emission cathode current so that the positive electrode temperature rises quickly and the positive electrode temperature is kept high. As a result, the variation of the amount of movement of the focus can be made small. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
