First experiments with the RF gun based injector for the Tesla Test Facility Linac

During 1997 and 1998 a first accelerator module was tested successfully at the TESLA Test Facility Linac (TTFL) at DESY. Eight superconducting cavities have accelerated the beam to an energy of more than 120 MeV. The injected 10 MeV electron beam was produced by a sub-harmonic injector using a thermionic gun, a buncher cavity, and one standard superconducting acceleration cavity. Since the achieved single bunch charge is not as high as required for a TESLA Linear Collider, a laser driven RF gun has been developed and been brought in operation late fall 1998. The aim of the new injector is to achieve the TESLA bunch charge and time structure, i.e. 8 nC bunches with 1 MHz repetition rate in 0.8 ms long bunch trains. This allows beam dynamics experiments in the TTFL. An overview of the injector is given and results of first experiments are described