Study on the longitudinal capture efficiency of a CW heavy-ion Linac

Purpose The continuous-wave (CW) linear accelerator, SSC-Linac, has been put into operation successfully as the new injector of Separate Sector Cyclotron (SSC) for Heavy Ion Research Facility in Lanzhou (HIRFL). The SSC-Linac is operated at the frequency of 53.667 MHz, which is the four times of the SSC operating frequency. In order to improve the longitudinal capture efficiency and increase the beam current extracted from the SSC, an independent multi-harmonics buncher (MHB) operating at a fundamental frequency of 13.417 MHz had been designed and manufactured.
Method This buncher adopts the dual-gap structure and sawtooth waveform is generated by multi-harmonics synthetized technology. Beam dynamics simulation with MHB was carried out and discussed in this paper. Furthermore, the beam commissioning using ^84 Kr ^14+ had been performed on SSC-Linac.
Results and conclusion The measured maximum capture efficiency 86.5% was obtained, which was well agreed with the simulation results. Due to the successful commissioning of MHB and the outstanding-performance of SSC-Linac, the extracted beam current from SSC has been improved one order of magnitude higher than before.