SFRFQ （Separated Function Radio Frequency Quadrupoles） accelerator is a new post accelerator of RFQ （Radio Frequency Quadrupoles） type, which has been developed since the beginning of the 1990s at Peking University. In order to demonstrate the possibility of the SFRFQ, a prototype cavity has been designed. A special dynamics design method has been proposed to avoid the sparking problem and decrease the energy spread at the exit of SFRFQ. It consists of two aspects： the asymmetry structure design for transverse focusing and the inner buncher design for longitudinal bunching. This allows the improvement of the beam properties without increasing the cavity length. The simulation results show that the energy spread can be substantially reduced by using the inner buncher in the SFRFQ structure.
To meet the requirements of developing SFRFQ and upgrading the 1 MeV ISR RFQ accelerator,an ECR O^+ ion source and LEBT system have been developed.Using two Einzel Lenses to focus the beam,more than 3mA O^+ beam with the energy of 22keV can be obtained at the end of LEBT.Its normalized root-mean-square emittance is about 0.12πmm·mrad.
