Generally, a standard bunching system is composed by an SW pre-buncher, a TW buncher and a standard accelerating section. However, there is one way to simplify the whole system to some extent by using the hybrid buncher, which is a combined structure of the SW pre-buncher and the TW buncher. Here the beam dynamics studies on an S-band bunching system with the hybrid buncher is presented, and simulation results show that similar beam performance can be obtained at the linac exit by using this kind of bunching system rather than the standard one. In the meantime, the structure design of the hybrid buncher is also described. Furthermore, the standard accelerating section can also be integrated with the hybrid buncher, which can further simplify the usual bunching system and lower the construction cost.
Purpose As the development of smaller accelerators technique,an X-band bi-period side-coupled accelerating structure has been designed for medical use.Methods The structure’s working frequency is 9.3 GHz.π/2 mode is chosen for the structure’s stability.There are 11 accelerating cells and 10 coupling cells,the first 5 of the accelerating cells work as non-light velocity part(βof the electron from 0.17 to 0.94),while the other 6 work as light velocity part.After CST simulation,the coupling constant between accelerating cells and coupling cells is 5%,and effi-cient shunt impedance is 142 MΩ/m.To feed power into the structure,a coupler is designed in the middle of the structure and the coupling coefficient is 1.4.Results After optimization,the particle’s capture efficiency is more than 30%,the particle energy is 2 MeV and the peak current is 60 mA,with the magnetron’s input power being 0.32 MW.Conclusion X-band side-coupled accelerator efficiency is high and is a more optimized design.This design is very meaningful for the development of smaller accelerators technique.
