Ion channel transport systems for high current electron beam accelerators

Summary Form only given, as follows. Experiments are underway to explore innovative transport systems for high-current, relativistic-electron-beam accelerators and free-electron lasers. Two unique, long-pulse, intense relativistic electron beam generators have been utilized for transport studies: MELBA (Michigan Electron Long Beam Accelerator) and a Febetron electron beam generator. Two different ion channel generation systems have been used. The first utilized a KrF excimer laser to preionize a channel in DEA (diethylaniline) gas at pressure from 0.1-1 mtorr. The second technique involves using a hot tungsten filament as a low-voltage electron source. Electron beam current injected into channels was in the range 200-300 A. Laser guided transport on MELBA was maintained for 0.6 mu s at 50% efficiency (defined as the ratio of injected beam current to transported beam current). Loss of transport was primarily a result of the cumulative effect of the REB-induced ionization of the DEA, causing the beam to become overneutralized (f/sub e/>1) late in the beam pulse. Experimental results from Febetron-generated electron beam transport in pure monatomic ion channels demonstrate the development of IFR beam transport from space-charge neutralization fractions in the range 0>