Cooling and Operation of the MSU Cyclotron Gas-Stopper Magnet

The two coils of the cyclotron gas-stopper magnet at Michigan State University (MSU) were each cooled down and filled with liquid helium made from 300-K gas separately using three PT415 coolers in the fall of 2014. The magnet was first powered in late 2014. During the process of powering the magnet, discharges occurred because the interlock system caused the magnet to discharge. As the magnet was powered to higher currents, the coil positions were changed using the cold mass support adjustments to ensure that forces on the cold mass supports were within the design limits. The force pattern on the cold mass supports was expected to change as the iron pole pieces saturated. Changes in the coil inductance were expected and observed as the iron pole pieces saturated. This paper describes the process that brings the magnet current up to its full current.