High-quality beam generation using an RF gun and a 150 MeV microtron

Low-emittance sub-picosecond electron pulses are expected to be used in a w ide field, such as free electron laser, laser acceleration, femtosecond X-r ay generation by Inverse Compton scattering, pulse radiolysis, etc. In orde r to produce the low-emittance sub-picosecond electron pulse, we are develo ping a compact Racetrack Microtron (RTM) with a new 5 MeV injection system adopting a laser photo cathode RF gun (Washio et al., Seventh China-Japan B ilateral Symposium on Radiation Chemistry, October 28, Cengdu, China, 1996) . The operation of RTM has been kept under a steady state of beam loading f or long pulse mode so far (Washio et al., J. Surf Sci. Sec. Jpn. 19 (2) (19 98) 23). In earlier work (Washio et al., PAC99, March 31, New York, USA, 19 99), we have succeeded in the numerical simulation for the case of single s hort pulse acceleration. Finally, the modified RTM was demonstrated as a us eful accelerator for a picosecond electron pulse generation under a transie nt state of beam loading. In the simulation, a picosecond electron pulse wa s accelerated to 149.6 MeV in RTM for the injection of 5 MeV electron bunch with a pulse length of 10 ps (FWHM), a charge of 1 nC per pulse, and an em ittance of 3 pi mm mrad. (C) 2000 Elsevier Science B.V. All rights reserved .