Development of the superconducting magnet system for a bioreactor

A superconducting magnet for a bioreactor system was developed in order to determine the biotechnical and biomedical responses of microorganisms to a high magnetic field. The magnet has a horizontal bore, and the field strength at the center is 7 tesla at an operating current of 120 Amperes. The room-temperature bore diameter is 160 mm. Persistent current mode and detachable power leads are adopted. A cryocooler was installed to cool the radiation shields, which enable continuous operation for 6 months without the need to resupply liquid helium. Magnetic shields cover the cryostat to minimize the leakage field. Two reactors are installed inside and outside of the bore. Magnetic shields also cover the outside reactor in order to reduce the strength of the magnetic fields to less than the geomagnetic level. The temperatures of the reactors are controllable, ranging from 283K to 343K with /spl plusmn/0.1K.<>