Research on backward traveling wave electron linac

Future electron linacs require high gradient acceleration. In this paper, t he studies on the high shunt impedance backward traveling wave electron lin ac accelerating structure (BTW) are presented. At first, the characteristic s of BTW are researched. The option of mode and optimal design methods of a ccelerating cavity for BTW are studied. A physical design method for BTW ac celerators, including longitudinal and transversal particle dynamics, is gi ven. Based on above studies, a 9MeV BTW accelerating tube at 3 pi/4 mode wi th frequency 2856MHz for inspecting large container as radiation source at customs is designed, and a comparison with disk-loaded waveguide accelerati ng tube is made. The result of research leads to the conclusion that backwa rd traveling wave accelerating structure is preferable. Because BTW has hig her effective shunt impedance, shorter filling time and more stable operati on.