Simulation study of a double-gap particle buncher for low-energy protons

Abstract

A continuous dc proton beam produced from an external ion source flows into an injector, which changes the direction of the ions into the plane where ions are accelerated by using an external radiofrequency (rf) electric field. However, the applied rf characteristics of the cyclotron only allow 10% of the injected beam to be accelerated while the rest of it is lost. A beam buncher is installed before the injector generates a pulsed beam from the continuous beam to increase the injection efficiency. The same external rf electric field applied at the buncher accelerates and decelerates the ions, forming a pulsed beam and thus improving the accelerated beam’s intensity. The buncher employed at Korea Institute of Radiological and Medical Sciences (KIRAMS) is used to measure the performance characteristics, which are compared with the the results of simulations of the ion’s time of flight. A buncher with the basic acceleration frequency increases the beam’s intensity by at least two times.