Magnets

A continuous magnetic field of 126 000 gauss, believed to be the strongest ever produced, has been generated at the Massachusetts Institute of Technology Lincoln Laboratory in a solenoid magnet about the size of a grapefruit, which was designed by Henry H. Kolm of the Laboratory staff. The Kolm magnet, which is reported to be six times as powerful as an iron‐core magnet producing the same volume field, consists mainly of a ribbon of thin copper, six inches wide at one end, tapering to an inch and a half at the other, and 135 feet in length. More than 3000 square channels have been cut into the ribbon, and when it is wound between insulating material, the channels line up in a spokelike pattern, permitting water to be forced through for cooling purposes. The 126 000‐gauss field is produced with an electric current of 10 000 amperes in a tube in the center of the coil, a space one inch in diameter by two inches long. Three hundred and twenty gallons of water per minute are used to dissipate the heat produced by 1 800 000 watts of electricity, the present limit of the MIT power supply. When a new source of 8 000 000 watts is installed, still stronger magnetic fields are expected.