Abstract: A traveling wave tube structure is used for propagation of an electron beam, and includes a metal tube member having an inner surface defining a hollow space, a helix member provided in the hollow space, and a plurality of supporting rods provided between the inner surface and the helix member and circumferentially spaced at predetermined angles from one another. Each of the supporting rods is formed from a quartz rod member covered with a substance selected from the group consisting of boron nitride and artificial diamond. The quartz contributes mechanical strength while the named covering substances are especially beneficial due to their dielectric constants and thermal conductivities.

Abstract: The discharge section of an ion laser tube is made up of a plurality of axially spaced pillar members, each accommodating and holding a respective capillary tube within a central hole, the capillary tubes defining the discharge path. The pillar members are made of high thermal conductivity material, such as aluminum nitride, while the capillary tuves are made of a material, such as silicon carbide, having a high durability under plasma bombardment. The gap between adjacent capillary tubes is preferably equal to or less than the inner diameter of the capillary tubes.