A superconducting magnetic lens for solar rays protection in manned interplanetary missions

During the interplanetary flights the crewmembers will be exposed to cosmic ray radiation (CR) with great risk for their health. The adsorbed dose due to CR depends on the galactic (GCR) or solar (SCR) origin. GCRs are isotropic and relatively high in energy and deliver a dose nearly constant. The SCRs are usually much less energetic, of the order of few tens of MeV but during some exceptional solar bursts, a great number of particles, mainly protons, are ejected at higher energies. In this case the dose delivered in a few hours by a solar burst inside a spacecraft can easily exceed 1 year cumulated dose by GCRs. The high-energy component of SCRs is quasidirectional so that a shielding system based on a superconducting magnetic lens (a toroid) can reduce the dose rate of SCRs to the level delivered by GCRs. This paper presents the concept, the general aspects and the main technical solutions that are adopted for this magnet.