Superconducting magnet with cryogenic thermal buffer

A superconducting magnet device (14; 46), including at least one coil winding (161-164) of superconducting wire, configured for generating a static magnetic field B0, wherein the at least one coil winding (161-164) is adapted to establish a thermally conductive contact with a cold head (38) of a cryocooler that is configured for bringing to and keeping the at least one coil winding (161-164) at a temperature below the critical temperature, and at least one gas-tight container (40;48) that permanently contains an amount of helium, wherein the at least one gas-tight container (40; 48) is in thermally conductive contact to the at least one coil winding (161-164) for taking up thermal energy from the at least one coil winding (161-164) in at least one operational state; and a magnetic resonance imaging system (10) that is configured for acquiring magnetic resonance images from at least a portion of a subject of interest (22), comprising such a superconducting magnet device (14; 46) for generating a static magnetic field B0 in an examination space (20) of the magnetic resonance imaging system (10).