Initial data of linac preinjector for SPring-8

The construction of the SPring-8 (Super Photon ring 8 GeV) linac was started in 1991 March. The preinjector of linac (2856 MHz, 60 pps) was already installed in Tokai Establishment of JAERI, and its commissioning is under way. We obtained the initial data of the electron gun, bunching section and several monitors. The electron beam is emitted by thermal cathode assembly, and extracted by 200 kV high voltage. Three types of grid pulsers were prepared to generate different pulse length, 1 nsec, 10-40 nsec and 1 /spl mu/sec. On the 1 nsec mode, this gun generated 22 A peak currents. The electrons were transported to the prebuncher along the magnetic field, about 600 Gauss, by eight helmholtz coils. The bunching efficiency was obtained to be 64-65%, and the energy spread was obtained /spl plusmn/2% at the energy of 9 MeV after the buncher with 2 MW RF power.<
>