Hartmann wavefront sensors and their application at FLASH

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• 作者：Barbara Keitel ; Elke Pl&ouml ; njes ; Svea Kreis ; Marion Kuhlmann ; Kai Tiedtke ; Tobias Mey ; Bernd Schä ; fer and Klaus Mann
• 关键词：wavefront ; Hartmann sensor ; free-electron laser ; soft X-rays
• 刊名：Journal of Synchrotron Radiation
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：23
• 期：1
• 页码：43-49
• 全文大小：898K
• ISSN：1600-5775

文摘

Different types of Hartmann wavefront sensors are presented which are usable for a variety of applications in the soft X-ray spectral region at FLASH, the free-electron laser (FEL) in Hamburg. As a typical application, online measurements of photon beam parameters during mirror alignment are reported on. A compact Hartmann sensor, operating in the wavelength range from 4 to 38 nm, was used to determine the wavefront quality as well as aberrations of individual FEL pulses during the alignment procedure. Beam characterization and alignment of the focusing optics of the FLASH beamline BL3 were performed with λ_13.5 nm/116 accuracy for wavefront r.m.s. (w_rms) repeatability, resulting in a reduction of w_rms by 33% during alignment.