Power handling ability of helices mounted in beryllium oxide

An investigation of the use of high-thermal-conductivity materials in microwave tubes is being conducted with particular emphasis on improving the average power handling capability of the traveling-wave tube helix structure. The normal helix structure supported by sapphire or alumina rods inside a glass or metal vacuum envelop must dissipate the heat generated by r-f losses and d-c beam interception primarily by radiation since cooling by conduction through the support structure is generally negligible. If the helix is supported in a fluted cylinder which is fabricated out of a high-thermal conductivity material, the traveling-wave tube is capable of operating at a much higher power level for a given helix temperature.