High power test of an injector linac for heavy ion cancer therapy facilities

Abstract

A hybrid single cavity (HSC) linac, combined with radio frequency quadrupole and drift tube structure in a single interdigital-H cavity, operates with high rf power as a prototype injector for cancer therapy synchrotron. The HSC adopts a direct plasma injection scheme (DPIS) with a laser ion source. The input beam current of the HSC is designed to be 20 mA ${\mathrm{C}}^{6+}$ ions. According to simulations, the HSC can accelerate a 6-mA ${\mathrm{C}}^{6+}$ beam which meets the requirement of the particle number for cancer therapy ($1{0}^{8\ensuremath{\sim}9}\text{ }\text{ions}/\text{pulse}$). The HSC injector with DPIS makes the existing multiturn injection system and stripping system unnecessary; what is more, it can also bring down the size of the beam pipe in existing synchrotron magnets, which can reduce the whole cost of the synchrotron. Details of the field measurements of the HSC linac and results of the high power test are reported in this paper.