Optimization of RFQ Structures for Acceleration of the Multicharged Ions with Different Charge to Mass Rations

This paper considers problems of RFQ channel optimization for acceleration of multicharged ions of different types. The capture ratio, emittance and current values of multi-charged ions may be better if the ions are preaccelerated before their injection into linear accelerator or booster synchrotron. For this reason, separate and simultaneous preacceleration of multicharged ions with different charge to mass (A/Z) ratios is considered here for a single radio-frequency quadrupole (RFQ) channel. The magnitude of the RFQ injection energy is about a few keV/u whereas the magnitudes of injection energy into a booster or the following linac cascade are ≥300 keV/u. In addition, we discuss the approach of the fast channel parameter optimization technique by using swarm computations and gradient descend for improving the capture ratio. The optimization is aimed at changing the regular part of the RFQ or matching section profile in order to improve the matching of the arbitrary oriented in phase space input beam.