3 May 2013 Hartmann wavefront measurements at FLASH
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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 λ13.5𝑛𝑚/ 116 accuracy for wavefront rms (W𝑟𝑚𝑠). 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 (W𝑟𝑚𝑠) by 33%.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Barbara Keitel, Barbara Keitel, Bernhard Flöter, Bernhard Flöter, Svea Kreis, Svea Kreis, Marion Kuhlmann, Marion Kuhlmann, Klaus Mann, Klaus Mann, Tobias Mey, Tobias Mey, Elke Plönjes, Elke Plönjes, Bernd Schäfer, Bernd Schäfer, Kai Tiedtke, Kai Tiedtke, "Hartmann wavefront measurements at FLASH", Proc. SPIE 8778, Advances in X-ray Free-Electron Lasers II: Instrumentation, 877814 (3 May 2013); doi: 10.1117/12.2020850; https://doi.org/10.1117/12.2020850

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