Feasibility of Single-Shot Microbunching Diagnostics for a Pre-Bunched Beam at 266 nm
| Autor: | Lumpkin, Alex, Rule, D.W. |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: | |
| DOI: | 10.18429/jacow-fel2019-wep041 |
| Popis: | Co-propagating a relativistic electron beam and a high-power laser pulse through a short undulator (modulator) provides an energy modulation which can be converted to a periodic longitudinal density modulation (or microbunching) via the R56 term of a chicane. Such pre-bunching of a beam at the resonant wavelength and the harmonics of a subsequent free-electron laser (FEL) amplifier seeds the process and results in improved gain. We describe potential characterizations of the resulting microbunched electron beams using coherent optical transition radiation (COTR) imaging techniques for transverse size (50 micron), divergence (sub-mrad), trajectory angle (0.1 mrad), spectrum (few nm), and pulse length (sub-ps). The transverse spatial alignment is provided with near-field imaging and the angular alignment is done with far-field imaging and two-foil COTR interferometry (COTRI). Analytical model results for a 266-nm wavelength COTRI case with a 10% microbunching fraction will be presented. COTR gains of 7 million were calculated for an initial charge of 300 pC which enables splitting the optical signal for single-shot measurements of all the cited parameters. Proceedings of the 39th Free Electron Laser Conference, FEL2019, Hamburg, Germany |
| Databáze: | OpenAIRE |
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