Analysis of Beam Dynamics Design of the He2+ RFQ LINAC

KOMAC has been developing a radio frequency quadrupole (RFQ) to use as the semiconductor irradiation system by accelerating helium beams. This 200 MHz RFQ can accelerate He2+ ions from an initial energy of 100 keV to 4 MeV with the peak beam current 10 mA and beam duty 1 %. The four-vane type is selected for higher efficiency at high frequency. The main design goals are to provide the 1.7 Kilpatrick as the maximum peak surface electric field while limiting the required rf power to less than 200 kW for the rf power economy point. The total length is limited as 3.2 m for the smooth brazing. The design specifications of the RFQ are listed in Table I. The beam dynamics design of 200MHz-He RFQ is done in PARMTEQM code. The cross section of the two dimensional surface of the RFQ cavity is made by the SUPERFISH code with the proper power dissipation. The more detail design for the electromagnetic field distribution will be started using the CST MWS code