Design and Simulation of Solenoid for Buncher of a Linear Accelerator

One of the most important components of a linac is buncher. Throughout most of the buncher, the electrons are well forward of the crest and have velocities considerably less than light velocity, thus they are in a region of radial defocusing and a considerable fraction of the beam will be lost unless defocusing action is counteracted by some other applied forces. The simplest way to do this is to set up a longitudinal magnetic field which interacts with the radial motion of the electrons and causes them to follow helical orbits through the space occupied by the field. In this paper, five solenoids were designed to provide necessary magnetic field inside the buncher. Magnetic field was analytically calculated and compared with simulation results of CST. Because of resistance in wires, some amount of energy appears in form of heat, so heat power was calculated analytically and cooling system was designed for these solenoids by ANSYS.