Supermagnet

To design a large supermagnet then, the resistivity of copper at the operating temperature, magnetic field and stress level is needed, together with the heat-transfer rate between copper and liquid helium in the particular coil geometry used. These parameters plus knowledge of the short sample characteristics of the superconductor enable one to design a stable magnet that need never quench.

Beneath the electronic revolution that began with the transistor lie the abstruse theories of a science called solid-state physics. Now physicists are working on new sources of light, supermagnets, metals that conduct electricity perfectly.

The Argonne supermagnet, doughnut-shaped and two feet in diameter, produced a magnetic field of 44,000 gauss— about 88,000 times stronger than the earth's magnetic field.

Whereas a conventional electromagnet might need a small power plant to operate it, the “'supermagnet” can be operated on an ordinary truck battery. This greatly reduces power costs. Incidentally, superconductivity is not new, even though experimentation with it began in earnest only in the 1960s. Since 1911 it has been known that cooling metals to absolute zero will cause resistance to disappear if electricity is passed through the metal at that temperature.