Recirculating Electrostatic Accelerators

A 3 MeV electrostatic accelerator has been modified for high electron current operation using beam recovery. In a simple configuration, a maximum of 99.4% of a 1.25 Ampere electron beam has been recovered. In a more complex beam transport system that includes a permanent magnet undulator as much as 95% of the beam has been recovered. These devices are ideally suited to drive efficient free-electron lasers Beam quality and beam recovery measurements are presented here.