Drift tube for generating radio frequency radiation from relativistic electron beam

摘要

Disclosed is a drift tube (122) comprising a hollow cylindrical conductive element having a periodic grating surface (123) formed on its inner surface. The ends (125) of the cylindrical conductive element are radiused to minimise electric stress buildup. The drift tube (122) is configured such that the interaction between a relativistic electron beam from an electron beam source passing through the inner space of the hollow element and the internal grating (123) produces radio frequency radiation by the Smith-Purcell effect. The frequency of the radio frequency radiation is determined by the spacing, face angle and geometry of the grating (123), as well as the energy of the electron beam.