CONTINUOUS TRANSMISSION-LINE MODELING OF A DTL INCLUDING BEAM LOADINGAND OTHER PERTURBATIONS

The rf structure of a DTL is first modeled by a circular waveguide fil led with an anisotropic medium with scalar permeability mu and tenser permittivity epsilon = ($) over cap z ($) over cap z epsilon(z) + ($) over cap r ($) over cap r epsilon(t). The two structures are equivalen t in four pertinent characteristics from which the waveguide parameter s and a radius a are determined. The exact geometry of the DTL includi ng the facing angles, the beam holes and the stems is used in the proc ess via SUPERFISH computations. A transmission line modeling the waveg uide is then established, which is further improved to include the fir st order effects of structure losses, beam loading and external rf sou rces. Comparisons with experimental results are favorable.