| 摘要 |
PROBLEM TO BE SOLVED: To prolong a lifetime by disposing a getter material in a quantity so as to adsorb discharge gas staying inside a tube for a long period. SOLUTION: A magnetron is provided with a cathode structural body including a filament 7 interposed between an upper end shield 17a and a lower end shield 17b, and two cathode leads 12a, 12b for supplying power to the filament 7. The cathode structure includes a ceramic spacer 18 for holding the two cathode leads 12a, 12b, a metal sleeve 19 inserted into at least one of the cathode leads 12a, 12b and caulked in abutment against the ceramic spacer 18 on the side of the lower end shield 12a so as to prevent axial movement of the ceramic spacer 18, and a getter material 20b filled in a clearance between the metal sleeve 19 and the cathode lead 12b.
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