Radiation-Resistant C-Type Dipole Dump Magnet for MIR/THz FEL Applications at TARLA

Abstract

Radiation-induced degradation remains a critical challenge for dipole magnets used in free electron laser (FEL) beam dump and spectrometer systems. This study presents the design, manufacturing, and performance evaluation of a radiation-resistant C-type dipole dump magnet developed for MIR/THz FEL beamlines at the Turkish Accelerator and Radiation Laboratory (TARLA). The magnet is optimized to provide a 42° bending angle for electron beams with energies up to 40 MeV. Three-dimensional magnetic field simulations, coupled with particle tracking in COMSOL Multiphysics and nuclear radiation analyses using the MCNP, demonstrate that the proposed dipole magnet generates a magnetic field of 0.457 T at an operating current of 24.5 A. Performance analyses confirm efficient beam deflection and reliable operation over the 2–45 MeV energy range, with reduced energy measurement errors for smaller RMS transverse beam sizes. Electromagnetic and thermal finite element analyses are conducted to ensure field uniformity, minimize fringe fields, and enhance radiation tolerance. Experimental characterization of the fabricated prototype shows strong agreement with simulation results, validating the proposed design. This work provides a robust and transferable approach for radiation-resistant magnet development in advanced FEL facilities.