Magnetic Field Measurements in a Cryomodule with Nearby Warm-Section Quadrupole Magnets of RAON Heavy Ion Accelerator

For the Korean heavy ion accelerator RAON, a normal-conducting quadrupole magnet doublet with an intermediate beam diagnostic devices between two cryomodules is served for collimating the heavy ion beam. Although the fringe field of a magnet at a superconducting cavity position is low enough, differently from a strong superconducting solenoid, it can degrade the acceleration performance in the case of quench of the cavity directly and/or indirectly by contaminating the cryomodule wall and magnetic shields. In this study, we analyze the magnetic measurement results in the cryomodule assembled with the magnet doublet compared to the calculated ones and discuss the future plan.