BEAM DYNAMICS OF A LINAC INJECTION SYSTEM.

The beam dynamics of chopper-buncher system for a tandem Van de Graaff was studied through a computer code. The chopper-buncher is of an advanced design, employing a compensated chopper, a harmonic pre-buncher and a post-accelerator final buncher. The computer program simulates the transfer of individual particles through the various optical elements of the complete system. Nonlinear effects and coupling of transverse and longitudinal motions, as well as random processes, were included in the computation. The ultimate goal of this system is beam pulses shorter than 100 psec over a wide range of ion masses, with a beam transmission of about 15%. This system can match the beam of a tandem Van de Graaff to the input of a linac.