AN ALTERNATIVE DESIGN CONCEPT FOR A I MHz BEAM CHOPPER FOR THE KAON FACTORY

Abstract

A high repetition rate ( lo6 discrete pulses/s) beam chopper operating at a 100% duty cycle is required to create holes in the beam for kicker magnet operation in the 5 rings in the proposed KAON Factory synchrotron. The results of prototype studies on a novel design for an energy efficient 150 kW beam chopper are described as the “reference” design in another paper at this conference [l]. Initial measurements are presented for an alternative method of pulse control which permits the deflection voltage to be twice the magnitude of the high voltage power supply level and thus twice that in the reference design. A 150 kW tetrode was mounted at the center of a 10 cm diameter low loss cable which is open circuit at one end and short circuit at the other end. In prototype tests at 3% duty factor, 7 kV electrical pulses were stored in the coaxial cable. By using a novel pulse control technique the magnitude of the stored pulses was quadrupled and the frequency at the open circuit end of the cable was halved. Results are shown in which the deflection voltage was 14 kV and rise and fall times were between 30 ns and 40 ns.