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arXiv · 1908.07468

Nano-Fabricated Free-Standing Wire-Scanners with Sub-Micrometer Resolution

G. L. Orlandi·C. David·E. Ferrari·V. A. Guzenko·B. Hermann·R. Ischebeck·E. Prat·M. Ferianis·G. Penco·M. Veronese·N. Cefarin·S. Dal Zilio·M. Lazzarino
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Abstract

Diagnostics of the beam transverse profile with ever more demanding spatial resolution is required by the progress on novel particle accelerators - such as laser and plasma driven accelerators - and by the stringent beam specifications of the new generation of X-ray facilities. In a linac driven Free-Electron-Laser (FEL), the spatial resolution constraint joins with the further requirement for the diagnostics to be minimally invasive in order to protect radiation sensitive components - such as the undulators - and to preserve the lasing mechanism. As for high resolution measurements of the beam transverse profile in a FEL, wire-scanners (WS) are the top-ranked diagnostics. Nevertheless, conventional WS consisting of a metallic wire (beam-probe) stretched onto a frame (fork) can provide at best a rms spatial resolution at the micrometer scale along with an equivalent surface of impact on the electron beam. In order to improve the spatial resolution of a WS beyond the micrometer scale along with the transparency to the lasing, PSI and FERMI are independently pursuing the technique of the nano-lithography to fabricate a free-standing and sub-micrometer wide WS beam-probe fully integrated into a fork. Free-standing WS with a geometrical resolution of about 250 nm have been successfully tested at SwissFEL where low charge electron beams with a vertical size of 400-500 nm have been characterized. Further experimental tests carried out at SwissFEL at the nominal beam charge of 200 pC confirmed the resilience to the heat-loading of the nano-fabricated WS. In this work, details on the nano-fabrication of free-standing WS as well as results of the electron-beam characterization are presented.

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G. L. Orlandi, C. David, E. Ferrari, V. A. Guzenko, B. Hermann, R. Ischebeck, E. Prat, M. Ferianis, G. Penco, M. Veronese, N. Cefarin, S. Dal Zilio, M. Lazzarino. 2019-08-20. Nano-Fabricated Free-Standing Wire-Scanners with Sub-Micrometer Resolution. https://doi.org/10.1103/physrevaccelbeams.23.042802

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