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

摘要

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 confi-guration, 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, liquid Helium from a 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.