Electron Linacs for Laser and Radiographic Applications

New electron inear accelerator configurations have been designed and a few have been constructed to satisfy the needs of unique laser and radiographic applications. In the laser applications, electron linacs are required that produce exceptional electron beam quality. For adequate gain in the free-electron-laser experiments, 20-MeV electron beams with excellent emittance, low energy spread and high instantaneous current are essential. Similar beam quality from a 5-MeV linac wil be required to provide high efficiency and high repetition rate pumping of KrF or XeF gases in future excimer lasers. For radiography, new electron linacs with a variety of energies and intensities are required for special applications. Two diverse examples of custom linacs that have been requested and for which conceptual designs have been completed are: 1) a 10-MeV linac operating with an x-ray dose rate of 3000R/min at lm while being subjected to extreme centrifugal and vibrational forces, 2) a light weight, highly portable 8-MeV linac with a dose rate of about 200R/min at lm for x-ray and possibly neutron radiography in adverse environmental conditions at remote locations. An unconventional inac configuration, the Klylac, has been studied both theoretically and experimentally. In the Klylac configuration, the Klystron and accelerator are arranged coaxially and in tandem. The same electron beam is used both to produce the rf power and as a source of electrons for acceleration.