Heavy ion induction linac studies at LBL

The authors present the results of recent experiments on the multiple beam induction linac MBE-4. This device models the low energy end of a driver for heavy ion inertial confinement fusion. The 16 meter long accelerator is comprised of four electrostatic AG focusing lattices each transporting a beam of singly charged cesium ions. All four beams are accelerated by a common set of induction pulsers consisting of a total of 24 accelerating gaps. Early experiments concentrated on an initial current of 10 mA per beam and successfully demonstrated amplification of the current, by controlled bunch compression, to 90 mA per beam while simultaneously accelerating the bunch from its injection energy of 200 keV (nom.) to 900 keV. In the course of these experiments an increase in the normalized emittance of the beam during acceleration (by a factor of 2) was observed while the emittance of the drifting beam remained constant during transport through the linac. Recent studies have centered on a single beam from MBE-4 which is extracted from a modified ion source