| Paper |
Title |
Page |
| TUPPH018 |
New Resonator for the Israeli FEL
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349 |
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- A. Faingersh, J. Dadoun, Kh. Garb, A. Gover, Y. Socol
University of Tel-Aviv, Faculty of Engineering, Tel-Aviv
- G. G. Denisov, M. Y. Shmelyov
IAP/RAS, Nizhny Novgorod
- M. Einat, B. Kapilevich, B. Litvak, Y. Pinhasi, A. Yahalom
CJS, Ariel
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The Israeli FEL resonator was re-designed in order to reduce the overall round-trip losses and achieve control on the radiation output-coupling. In its new configuration, the resonator consists of overmoded corrugated rectangular waveguide and two radiation mode splitters, separating the high-energy e-beam from the laser radiation. The electron input splitter is based on Talbot effect in an overmoded rectangular waveguide. The radiation out-coupling is done in the output splitter. It is based on novel design and it combines Talbot effect between two parallel plates with free space propagation, and focusing by two curved cylindrical mirrors in a confocal imaging scheme. The waveguide and the splitters were tested experimentally, showing improved performance in comparison with the former resonator. The measured unloaded Q-factor of the new version is increased by a factor of ~ 3, attaining up to Q=30,000. Accordingly, the round-trip losses are ~15%. Rotating grids control the radiation out-coupling allowing wide variation for maximization of the radiation output power and extraction efficiency. The design layout and the testing results are presented.
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| TUPPH035 |
Generation of Superradiant Pulses by Backscattering of Pumping Wave on the Intense Electron Bunch
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400 |
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- N. S. Ginzburg
JINR, Dubna, Moscow Region
- V. I. Belousov, G. G. Denisov, A. Sergeev, I. V. Zotova
IAP/RAS, Nizhny Novgorod
- A. G. Reutova, K. A. Sharypov, V. G. Shpak, S. A. Shunailov, M. R. Ulmaskulov, M. I. Yalandin
RAS/IEP, Ekaterinburg
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Recently significant progress was archived in the generation of multimegawatt subnanosecond pulses in millimeter wave band utilizing the cyclotron and Cherenkov mechanisms of superradiance (SR). We study the novel mechanism of SR when the powerful pumping wave undergoes the stimulated backscattering on the intense electron bunch. Due to the Doppler up shift the radiation frequency can significantly exceed the frequency of the pumping wave. With the relativistic microwave generator as a pumping wave source such a mechanism can be used for generation of the powerful pulse radiation in the short millimeter and submillimeter wave bands. Experiments on the observation of the stimulated scattering in the superradiance regime were carried out at Institute of Electrophysics RAS with two synchronized accelerators. The 4 ns electron beam from the first accelerator is used for generation of the 38 GHz 100 MW pumping wave which subsequently scattered on the subnanosecond 250 keV 1 kA electron bunch produced by the second accelerator. The SR pulses with duration 200 ps and peak power about 1 MW were generated. The spectrum of scattered signal included the frequencies up to 150 GHz.
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