A. Doria, V.B Asgekar (a), D. Esposito(b), G.P. Gallerano, E.Giovenale, G. Messina, C.Ronsivalle
ENEA- Divisione di Fisica Applicata, P.O. Box 65, 00044 Frascati - Italy; (a)University of Pune, INDIA; (b) ENEA-student
The coherent radiation generated by a radio-frequency modulated electron beam passing through an undulator can be significantly enhanced by a proper ramping of the electron energy within the bunch duration. An accelerating structure suitable for the systematic investigation of energy-phase correlation effects has been constructed at ENEA-Frascati. It consists of a pulsed triode gun followed by a 2 MeV S-band linac and a phase-matching section (PMS). The PMS is made of three coupled cavities tuned at the linac frequency. The distribution of the electrons in the phase space is controlled by varying the phase and the amplitude of the RF field in the PMS with respect to the linac. The accelerated beam is injected into a rectangular waveguide placed within the gap of a permanent magnet undulator, where it generates coherent millimeter and sub-millimeter wave radiation. The construction of the linac has been completed and the RF system has been tested. It delivers 10 MW of RF power at 3 GHz, split in two branches by a 3 dB coupler. The linac and the PMS are driven by a high-power phase-shifter in the range (0-360°) and a variable attenuator (0-15 dB) respectively. Preliminary results on the accelerator performance will be reported.
