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arXiv · 1801.02878

RF injector design studies for the trailing witness bunch for a plasma-based user facility

A. Giribono·A. Bacci·E. Chiadroni·A. Cianchi·M. Croia·M. Ferrario·A. Marocchino·V. Petrillo·R. Pompili·S. Romeo·M. Rossetti Conti·A. R. Rossi·C. Vaccarezza
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Abstract

The interest in plasma-based accelerators as drivers of user facilities is growing worldwide thanks to its compactness and reduced costs. In this context the EuPRAXIA collaboration is preparing a conceptual design report for a multi-GeV plasma-based accelerator with outstanding electron beam quality to pilot, among several applications, the operation of an X-ray FEL, the most demanding in terms of beam brightness. Intense beam dynamics studies have been performed to provide a reliable working point for the RF injector to generate a high-brightness trailing witness bunch suitable in external injection schemes, both in particle beam and laser driven plasma wakefield acceleration. A case of interest is the generation of a witness beam with 1 GeV energy, less than 1 mm-mrad slice emittance and 30 pC in 10 fs FWHM bunch length, which turns into 3 kA peak current at the undulator entrance. The witness beam has been successfully compressed down to 10 fs in a conventional SPARC-like photo-injector and boosted up to 500 MeV in an advanced high-gradient X-band linac reaching the plasma entrance with 3 kA peak current and the following RMS values: 0.06% energy spread, 0.5 mm-mrad transverse normalised emittance and a focal spot down to 1 $\mu m$. RF injector studies are here presented with the aim to satisfy the EuPRAXIA requests for the Design Study of a plasma-based user facility.

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A. Giribono, A. Bacci, E. Chiadroni, A. Cianchi, M. Croia, M. Ferrario, A. Marocchino, V. Petrillo, R. Pompili, S. Romeo, M. Rossetti Conti, A. R. Rossi, C. Vaccarezza. 2018-01-09. RF injector design studies for the trailing witness bunch for a plasma-based user facility. https://doi.org/10.1016/j.nima.2018.01.042

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