Generation of ultra-short electron bunches for light source research

Abstract

An S-band thermionic 1.5-cell rf gun injector system is being built at NSRRC for Taiwan Photon Source (TPS) booster. At optimized field ratio, an electron beam with linear energy chirp can be generated by the rf gun. The beam is then compressed by an alpha magnet such that ultra-short electron bunches at femto-second bunch length can be obtained. Particle dynamics has been studied for an rf gun with nose cone at the cathode, simulation results show that 74 pC bunches at about 97 fs is achievable. Some of the critical components such as the rf gun and alpha magnet have been fabricated and being tested in house. Experiments for intense coherent THz radiations and tunable femto-second X-ray from ultra-short bunches are being proposed as future applications. © World Scientific Publishing Company.