Hartmann wavefront measurements at FLASH

Barbara Keitel; Bernhard Flöter; Svea Kreis; Marion Kuhlmann; Klaus Mann; Tobias Mey; Elke Plönjes; Bernd Schäfer; Kai Tiedtke

doi:10.1117/12.2020850

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3 May 2013 Hartmann wavefront measurements at FLASH

Barbara Keitel; Bernhard Flöter; Svea Kreis; Marion Kuhlmann; Klaus Mann; Tobias Mey; Elke Plönjes; Bernd Schäfer; Kai Tiedtke

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Proceedings Volume 8778, Advances in X-ray Free-Electron Lasers II: Instrumentation; 877814 (2013) https://doi.org/10.1117/12.2020850
Event: SPIE Optics + Optoelectronics, 2013, Prague, Czech Republic

Abstract

We report on online measurements of photon beam parameters during mirror alignment in the soft x-ray spectral region of FLASH, the free-electron laser in Hamburg. A compact Hartmann sensor operating in the wavelength range from 6 to 35nm was used to determine the wavefront quality of individual free-electron laser (FEL) pulses during the alignment procedure as well as aberrations. Beam characterization and alignment of beamline BL3 was performed with λ_13.5𝑛𝑚/ 116 accuracy for wavefront rms (W_𝑟𝑚𝑠). Second moment beam parameters are computed using a spherical reference wavefront generated by a 5μm pinhole. The Hartmann sensor was used for alignment of the ellipsoidal focusing mirror of beamline BL3, resulting in a reduction of (W_𝑟𝑚𝑠) by 33%.

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Barbara Keitel, Bernhard Flöter, Svea Kreis, Marion Kuhlmann, Klaus Mann, Tobias Mey, Elke Plönjes, Bernd Schäfer, and Kai Tiedtke "Hartmann wavefront measurements at FLASH", Proc. SPIE 8778, Advances in X-ray Free-Electron Lasers II: Instrumentation, 877814 (3 May 2013); https://doi.org/10.1117/12.2020850

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