Design of a 200-MHz continuous-wave radio frequency quadrupole accelerator for boron neutron capture therapy

摘要

A high-intensity continuous-wave(CW) radio frequency quadrupole(RFQ) accelerator is designed for boron neutron capture therapy.The transmission efficiency of a 20-mA proton beam accelerated from 30 keV to 2.5 MeV can reach 98.7% at an operating frequency of 200 MHz.The beam dynamics have a good tolerance to errors.By comparing the high-frequency parameters of quadrilateral and octagonal RFQ cross sections,the quadrilateral structure of the four-vane cavity is selected owing to its multiple advantages,such as a smaller cross section at the same frequency and easy processing.In addition,tuners and undercuts are designed to tune the frequency of the cavity and achieve a flat electric field distribution along the cavity.In this paper,the beam dynamic simulation and electromagnetic design are presented in detail.