A Pulsed Beam Shutter for Radio-Frequency Separated Beams at the ZGS

A pulsed beam shutter magnet is required to deflect a beam of separated high energy particles into a beam stop after a desired number of particles have reached the 12-ft bubble chamber at the ZGS. The magnet has a core, wound from 2 mil grain-oriented steel, an aperture 15 cm × 15 cm, and a ¿Bdl=1kGm. The pulse has a risetime of ¿3 ¿s and a flattop of 40 ¿s. The above is achieved by discharging a high voltage capacitor bank into the magnet inductance, followed by a power-crowbar. The design of the magnet and the switching circuits is described and formulas for calculating the pulse shapes are given. Graphs of calculated flattops to 500 ¿s are shown.