Experiments with Megagauss Targets at SLAC

The high pressures and current densities associated with MG fields limit their useful lifetime to 1 ¿sec or less. The pulse duration of the SLAC electron beam being of the same order of magnitude, a successful marriage of the two techniques was achieved in experiments that use transverse fields in the range 1 to 2 MG as targets for a 19 GeV electron beam. The fields were generated in volumes of dia. 3 to 5 mm by discharging a very fast capacitor bank into small single turn coils, or by flux compression with electromagnetically driven aluminum foils. The termination of the capacitor bank, designed to minimize the destructive effects of the exploding coils, permitted a repetition rate of one shot per hour. Magnetic bremsstrahlung emitted by the electrons was recorded on X-ray film and nuclear emulsions. In an additional experiment, nuclear emulsions mounted in the high field region survived the violent self-destruction of the coils. In these, the magnetic deflection by far exceeds the multiple scattering, which is normally the dominant effect in nuclear emulsions.