FEL beam characterization from measurements of the Wigner distribution function

Radiation characteristics of extreme UV and soft X-ray sources

“…The derived equation corresponds to the projection slice theorem of tomography which states that in Fourier space, intensity profiles represent slices of the Wigner distribution function, as defined by the transformation matrices A and B [122,123]. In other words, intensity information of a beam can be employed to reconstruct its a priori unknown Wigner distribution.…”

Strahlcharakterisierung von Freie-Elektronen-Lasern im weichen Röntgen-Spektralbereich

“…Synchrotronquellen [35] und Freie-Elektronen-Lasern [36]. Dieses Verfahren wird auch hier verwendet (in leicht angepasster Form) und in Kapitel 6 näher beschrieben.…”

“…interpoliert mit der Lage der Strahltaille z 0i und i = x, y [36]. Durch Rücktransforma-tion wird die Wignerfunktion berechnet.…”

“…An den in Abbildung 6.2 gezeigten Strahlprofilen der EUV-Kamera Nahe der Fokusposition (z = −39mm, 1mm, 22mm) ist dies noch nicht zu erkennen, doch die Profile bei größerem z (-63mm, 53mm) zeigen diese Modulation des Fernfelds entlang der x-Achse bereits [36]. Die…”

Mapping the transverse coherence of the self amplified spontaneous emission of a free-electron laser with the heterodyne speckle method

“…Data coming from different radiation pulses are merged together, losing any possibly attractive information coming from a statistical analysis. Wavefront analysis using Hartmann Wavefront Sensors was proposed to determine the spatial characteristics of the FEL source in single-shot regime [17] and demonstrated at the SCSS Test Accelerator [18], at FLASH [19,20] and at FERMI [21]. At LCLS, besides the study about the wavefront [22], an evaluation of the transverse coherence in the X ray range has been performed by measuring the homodyne speckle intensity due to coherent diffraction by disordered samples in the low and wide angle configurations [23], paving the way for the application of statistical methods on FELs.…”