Commissioning the Felix Bunching System

The FELIX injector consists of a thermionic triode gun driven at 1 GHz, a 1 GHz subharmonic prebuncher, and a travelling wave (3 GHz) buncher. Further acceleration will be achieved with two identical constant-gradient, travelling-wave (3 GHz) linacs. The buncher, which provides an exit energy of 4 MeV, has the feature that an unambiguous relation between the particle phase and energy is established. In this article we report our experiences in commissioning the bunching system. This includes a discussion of the gun characteristics, emittance measurements with and without rf modulation, and investigations of the achievable pulse length behind the gun.