Investigation results on the transport of high-current electron beam in the system of periodic focusing at the LIU-30 accelerator

Specifications were obtained at the LIU-30 30 MeV linear induction accelerator designed for the production of electron beam with the current of 250 A and pulse duration 250 A in injection section with the energy of 3 MeV in solenoidal magnetic field. 5 acceleration sections (AS), each designed for the energy increase of 5.5 MeV, specify beam transport in the system of periodic focusing (SPF). The SPF optimization is performed for the minimum growth of the coherent oscillations amplitude in the range from 1 to 3.8 KGs while passing from the first AS to the fifth one, changing the distance between them from 5.5 to 1.2 m. The number of short solenoids was 120. It is worth noting that in a sectionized metal-ceramic tube (SMCT) is it possible to transport the current two times higher than in a resistive tube. A beam with the current of 200-250 A had instant emittance of 0.35-0.4 cmxrad, effective emittance reached 0.6-0.65 cmxrad. With the collimator which transmitted about 40% of the electron source current the course current was 70 A and had emittance 0.15 cmxrad. However, in the end of the first AS effective emittance was also 0.6 cmxrad, which may coincide with the SPF acceptance of the first AS. 6 refs.; 6 figs