Two magnets set records for field intensity

A record for the most intense continuous magnetic field was set in February by a 254‐kG solenoid and then surpassed in July by a 301‐kG solenoid. Both magnets were hybrids built at MIT's Francis Bitter National Magnet Laboratory (NML). The designs were described at the 6th International Conference on Magnet Technology at Bratislava in August by the magnets' developers—Mathias J. Leupold, Robert J. Weggel and Yukikazu Iwasa, all of NML. A hybrid magnet consists of a large superconducting coil surrounding a compact water‐cooled coil. The concept was proposed in 1965 by D. Bruce Montgomery of NML and Martin Wood of Oxford, as a method for efficiently generating a large magnetic field without unduly reducing the volume available for experiments in the central cavity. (The inner bore of both record-setting magnets is 3.2 cm.)