New method of integrating periodic permanent magnet (PPM) assembly in traveling wave tubes (TWTS)

Abstract

In traveling wave tube (TWT) amplifiers, an axial focusing magnetic field is required to keep electrons traveling in a narrow, pencil-like beam over the considerable length of the circuit. Conventionally, this focusing has been accomplished by using a periodic permanent magnet system housing axially polarized ring magnets. Making the structure to this point has been a complicated process consisting of brazing multiple metals together and honing the piece to the desired specifications. We present a new method of fabricating this housing structure monolithically using iron, developing magnetically oversaturated housing regions, and saving processing time and effort.