Cold Tests and Magnetic Characterization of a Superconducting Magnet for a Compact Cyclotron for Radioisotope Production

A superconducting magnet able to provide the required field of 4 T has been developed for a compact cyclotron to produce radioisotopes for medical imaging, in the framework of the AMIT project. It consists of two coils in Helmholtz configuration, embedded in a stainless steel casing to hold the Lorentz forces. The cooling scheme is based on a low pressure forced internal flow of two-phase liquid-vapour helium through a narrow channel machined in that casing. This paper reports on the cooling tests and the preliminary magnetic measurements of the magnet. Regarding cooling tests, liquidHelium froma Dewar has been used first to train the magnet and to estimate the thermal losses. Later, refrigeration will be accomplished from a stand-alone cryogenic supply system that would allow a user-friendly operation of the cyclotron, without external supply of cryogens. Regarding magnetic measurements, a custom magnetic measurement bench developed in collaboration with ALBA/CELLS, has been used to map the magnetic field and first results are presented and discussed in this paper.