| 摘要 |
1,196,398. Travelling-wave tubes. VARIAN ASSOCIATES. 17 Feb., 1969 [19 Feb., 1968], No. 8549/69. Heading H1D. A slow-wave circuit is introduced into and mounted within the bore of the body portion of a microwave tube by gluing it on a mandrel, heating the body portion to expand the bore, and introducing the mandrel, cooled by a coolant flowing therethrough to prevent melting of the glue, into the expanded bore, whereafter the body portion is allowed to cool and provide an interference shrink-fit on the slow-wave circuit, and the glue is removed-by a solvent, for example. As described, the method is applied to a simple helix 1 mounted between three support rods 3 of beryllium oxide, alumina, boron nitride, or sapphire, which mayafter they have received a lossy coating of pyrolitically deposited carbon-be fixed to the helix by glue brushed on at the same time as the helix is glued to the steel mandrel 2. Flats are thereafter ground on those portions of the rods which will contact the tube body, as shown. The tube body may be formed of a tubular stack of alternatively magnetic and non- magnetic rings (Fig. 8, not shown), and is heated to about 800‹ C. in a N 2 /H 2 atmosphere to expand the bore. Reference is additionally made to the use of the method with bifilar or cross-wound helices, or with ring-bar structures. |
