| 摘要 |
<p>PROBLEM TO BE SOLVED: To properly conduct heat transfer from a heater wide to a cathode sleeve for the prevention of the breakage of a coat layer by winding the heater wire having the surface covered with an insulating material on the circumferential surface of the cathode sleeve consisting of a conductive material and having a cathode base, and covering the heater wire with a coat layer. SOLUTION: A circular cathode base 11, consisting of a porous V base with a porosity of about 20% impregnated with an electron-emitting material is fitted and brazed to one end opening part of a cylindrical cathode sleeve 12 formed of Mo and having openings in both ends. The surface of a heater wire 13 formed of a conductive metal (for example, copper) is covered with an insulating coating layer 14 of about 100μm thickness formed by electrode position by the use of, for example, alumina, and the heater wire 13 is wound directly on the circumference of the cathode sleeve 12. A cost layer 15 of about 0.35 mm thickness is formed adhering closely on the circumferential surface of the cathode sleeve 12 having the heater wire 13 wound thereon by plasma flame coating, and fixed so as not to be peeled off by an external force. As a result of this, a cathode structure in which the heater wire 13 is surely fixed can be provided.</p> |
