LINAC2026 - 33rd Linear Accelerator Conference

Longitudinal Acceptance Improvement via RF Phase Retuning in RAON Superconducting Linac Beam Commissioning

Not scheduled

2h

Daejeon Convention Center

Poster Presentation MC1.A01: Beam Dynamics, beam simulations, beam transport Poster Session

Speaker

Ji-Ho Jang (Institute for Basic Science)

Description

The RAON superconducting linac consists of quarter-wave resonator (QWR) and half-wave resonator (HWR) sections and is designed to accelerate ion beams from protons to uranium, with a uranium beam energy of up to 18.5 MeV/u. During the 2026 beam commissioning, three QWR cavities and eight HWR cavities were not available for operation. The absence of multiple cavities can disturb the longitudinal beam dynamics by changing the energy gain and synchronous phase profile from the nominal lattice. This may reduce the longitudinal acceptance and increase the risk of beam loss. To mitigate this effect, RF phases of the cavities both upstream and downstream of the inactive cavities were retuned to keep the beam within the stable RF bucket. In this work, simulation and experimental studies on this phase-retuning method are presented. The results show that appropriate RF phase adjustment can compensate for missing cavity operation, improve the longitudinal acceptance, and enhance beam transmission during superconducting linac commissioning.

Funding Agency

This work was supported by the Institute for Basic Science (IBS-I001-D1).