Commissioning results of single bunch selection system for the RAON heavy-ion accelerator facility

To enable neutron time-of-flight experiments at the RAON heavy-ion accelerator facility, we tested a single bunch beam selection method by combining an RF chopper and a double gap buncher in the low-energy beam transport section. The RF chopper converts a CW beam into a hundreds-nanosecond pulsed beam. Then, the double gap buncher performs bunching to shorten the pulse length to less than one radio frequency quadrupole (RFQ) cycle. Ideally, a single isolated bunch can be achieved after the RFQ. In this study, we discuss the design concept of the single bunch selection system and present initial beam commissioning results.