Experimental study of compact FEL with micro wiggler and electrostatic accelerator

A compact FEL for submillimeter and far infrared regions is studied at the Institute of Space and Astronautical Science. The FEL can be compact by using an electrostatic accelerator and a micro wiggler. The electrostatic accelerator (DISKTRON) with a diameter of 1 m can generate up to 1 MV continuously. The micro wiggler is fabricated using permanent magnets made from Nd–Fe–B. (period: 8 mm, total length: 248 mm, gap: 2–10 mm, K parameter: 0.07–0.7) An electron beam of high quality is generated by means of a photo cathode. (731 kV, 1.5 A, 25 ns, 2 mmφ, ΔE/E:0.18%) In the preliminary phase, detection of the FEL at the millimeter wave region of 96 GHz is conducted. The electron beam is injected into a resonator with Distributed Bragg Reflector. A small millimeter wave signal has been detected.