| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase a withstand voltage characteristic of a radiation generating unit 10 in which a radiation generating tube 20 which generates radiation by applying voltage between a cathode 22 and an anode 23 provided at both ends of a tubular member 26 is stored within a storage container 12 filled with an insulative substance 18.SOLUTION: The tubular member 26 has an annular protrusion 27 on an outer periphery thereof, and when a relative dielectric constantεof the insulative substance 18 is greater than a relative dielectric constantεof the tubular member 26, the distance between the cathode 22 and the anode 23 is L, the shortest distance between the cathode 22 or the anode 23 and the protrusion 27 is d, the rise angle of the protrusion 27 from the surface of the tubular member 26 at the position with the distance d isθ, the width of the protrusion 27 is W, and the height of the protrusion 27 is H, the relations expressed by the following expression (1) is satisfied. 1>d/L≥0.001×ln(H/W)-0.001×ln[cos(θ)]-0.004×(H/W)×cos(θ)+0.004 ...(1)</p> |
