Conceptual design of LEBT and RFQ for the HIAF linac

In this paper, we present conceptual design and beam dynamics analysis of the Low Energy Beam Transport (LEBT) and Radio Frequency Quadrupole (RFQ) for the linac section of a heavy ion accelerator facility, high intensity Heavy Ion Accelerator Facility (HIAF) project, which is promoted by the Institution of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS). A novel scheme is prompted that a Multi-Harmonic-Buncher (MHB) is used for bunching the continuous beam up-stream of the RFQ. The modulation m and synchronous phase ψ of the RFQ do not start from 1.0 and −90° but 1.05 and −45° instead. The results indicate that it is possible to keep transverse emittance growth within tolerable limits while the longitudinal emittiance is much smaller than the design without an external buncher.