Design of high power electron linac at PNC

A high power CW (Continuous Wave) test electron linac was designed to develop a higher power linac to transmute radioactive wastes. The test linac is energized by two 1.2MW CW L-band klystrons to produce an electron beam with the energy of 10MeV and current of 100mA. The average beam power is 200kW-1MW for the duty factor 20-100%. In designing such a high power linac, authors selected a traveling-wave accelerator with TWRR (Traveling Wave Resonant Ring). This is to enhance the threshold current of BBU (Beam Break-Up) and to get high accelerator efficiency that results from the low value of attenuation constant τ and high field multiplication factor M which are permitted only with TWRR. A kind of efficient cooling structure is adopted to an accelerator structure in order to disperse the generated heat by RF (Radio Frequency). The variational method is used to calculate the sizes and parameters of the disk-loaded accelerator structure employed. There is a discrepancy of the order of a few hundredth of one percent between the calculated sizes and the experimental ones. The M determined in the design agreed well with those measured in low and high power tests. (author)