| 摘要 |
<p>PROBLEM TO BE SOLVED: To lower a heat conduction loss and electric power consumption and to prevent stray emission from the periphery of a grid hole. SOLUTION: This impregnated cathode structure 65 is provided with a cylindrical internal sleeve 41 holding a cathode 45 at one end in the axial direction, a cylindrical external sleeve 47 with different diameters having a small outside diameter part 49 at one end in the axial direction and a large outside diameter part 51 at the other end, and a cylindrical holder 55 having an inside diameter approximately equal to the outside diameter of the large outside diameter part 51 of the external sleeve 47 and fixed to an insulating support member 61. Here, the internal sleeve 41 is supported inside the small outside diameter part 49 of the external sleeve 47 through a supporting body 53, and the periphery of the large outside diameter part 51 is fixed to the internal circumference of the holder 55.</p> |
