To provide a vacuum tube of a kind that does not have a defect relating to the characteristics of the operation, reliability and service life of the vacuum tube, and can be manufactured substantially more economically.

This relates to a vacuum tube (1) for power process or conversion, for instance, an X-ray tube or a traveling wave tube having at least one surface that is cooled during operation by heat radiation together with a getter that is useful for avoiding undesirable pressure increase. In particular, the tube is provided in a manner in which the getter is partially or wholly cooled on the surface of a tube (1) that is cooled, and the coating has such a thickness that has temperature radiant power suitable for cooling.