Prototype studies of a 1 MHz chopper for the kaon factory

The 1.025-MHz beam chopper will create 108-ns gaps in the 1GeV/c H/sup -/ beam to allow enough time for the magnetic field to be established in the kicker magnets in each of the 5 accumulator rings of the kaon factory at the Tri-University Meson Facility (TRIUMF). The required deflection of 1 mrad can be achieved with a set of plates 5-cm apart in which the product of voltage difference and plate length is 37.7 kV-m. The kick must have a rise and fall time of less than 39ns and a flat top of 49ns, and 92ns on alternate pulses. The 1-MHz chopper concept involves an energy storage system where the electric pulses are stored in a large-diameter low-loss coaxial cable. Measurements of the performance of a high-voltage prototype are presented. Results show that this novel design can be implemented successfully for the kaon factory.<>