ESTIMATION AND CORRECTION OF THE UNCONTROLLED BEAM LOSS DUE TO THE ALIGNMENT ERROR IN THE LOW-ENERGY LINEAR ACCELERATOR OF RAON

RAON(Rare isotope Accelerator Of Newness) mainly consists of the front-end system, ISOL system, reaccelerator for ISOL system, charge stripper section and main linear accelerator(linac) for ECR ion source [1]. Since the beam energy at the down-stream of the front-end system is low, 0.3 0.5 MeV/u, the trajectories of the beam is very sensitive to the alignment error of the magnets and cavities at the entrance of the main linac. It can cause the uncontrolled beam loss due to the large amplitude of the trajectory. The effect of the alignment errors of the magnets and cavities was estimated and corrected by using analytical model which is based on analytical model and code TRACK [2]. The calculation result based on the analytical model agrees very well with the simulation by using the TRACK code. Using the analytical model, the position and number of the corrector and Beam Position Monitor(BPM) in low energy linac was determined to compensate the amplification of the beam trajectory under 400 um. We will present the result of the estimation of the alignment error and the correction using steering magnet with strip-line Beam Position Monitor (BPM) in a low energy section.