| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for restricting the lowering of degree of vacuum in a getter part capable of sufficiently adsorbing the gas by arranging the getter part in a recessed part of a member for supporting a negative electrode part inside of a case. SOLUTION: A glass stem 4 holds the whole of a negative electrode structure and secures vacuum tightness, and a lead wire 5 for applying electrical potential from outside is sealed in a vacuum tube. A getter part 7 is supported by the lead wire 5 at a tube inside through a nickel wire 6 in the condition that a vapor spraying direction thereof is directed to the inner wall side of a cylinder 2 so as to prevent the generation of a contact of the getter part 7 with the peripheral part of a sheath 3. In the getter part 7, barium or the like is sealed in a columnar container made of nickel or the like formed into a recessed part. The getter part 7 is sealed after evacuating a bulb of an X-ray tube device so as to maintain the inside of the tube at a high degree of vacuum. A vapor spraying area is widened so as to increase the adsorbed amount in total, and a room for adsorbing further much gas is obtained.
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