Generation of sheet electron beams for experiments on a wiggler-focused small period free electron laser amplifier

A new explosive field emission material, tungsten graphite, is found to have better performance than velvet or reactor grade graphite in terms of current density, emittance and durability. Current density and normalized emittance versus electric field are measured. A free electron laser amplifier with sheet electron beam and small period planar wiggler has been operated successfully using this kind of electron emission material.