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@INPROCEEDINGS{Roth:206992,
      author       = {Roth, Thomas and Helfen, Lukas and Hallmann, Joerg and
                      Samoylova, Liubov and Kwaśniewski, Paweł and Lengeler,
                      Bruno and Madsen, Anders},
      editor       = {Morawe, Christian and Goto, Shunji and Khounsary, Ali M.},
      title        = {{X}-ray {L}aminography and {SAXS} on {B}eryllium {G}rades
                      and {L}enses and {W}avefront {P}ropagation through
                      {I}mperfect {C}ompound {R}efractive {L}enses},
      volume       = {9207},
      reportid     = {PUBDB-2015-01039},
      series       = {Advances in X-Ray/EUV Optics and Components IX},
      pages        = {920702-1 -- 920702-12},
      year         = {2014},
      comment      = {Proc. SPIE 9207, Advances in X-Ray/EUV Optics and
                      Components IX},
      booktitle     = {Proc. SPIE 9207, Advances in X-Ray/EUV
                       Optics and Components IX},
      abstract     = {Hard X-ray free electron lasers provide almost fully
                      transverse coherent X-rays. Though the natural divergence of
                      these X-rays is a few micro-radians, they still need to be
                      collimated or focused while traveling up to 1km towards the
                      sample. This can be done with beryllium compound refractive
                      lenses (CRLs). Due to the coherence of the beam, it is
                      important that the impurities or granular boundaries in
                      these CRLs do not distort the wavefront of the X-ray beam to
                      a measurable extend. We measured the SAXS signal of various
                      beryllium grades and of 2D parabolic lenses made of IF-1
                      beryllium. Then, we imaged these samples using X-ray
                      computed laminography at a resolution of around 1
                      micrometer. Computed laminography is a 3D imaging technique
                      similar to computed tomography, but particularly adapted for
                      at extended objects. These measurements are used to
                      characterize the voids and granular boundaries in the
                      beryllium samples. Boundaries between the former powder
                      particles are easily seen for beryllium grades produced via
                      powder metallurgy methods. This is not the case for cast
                      ingots. Common to all samples are voids with diameters in
                      the 10 micrometer range as well as smaller sized, denser
                      impurities. Finally, we use wavefront propagation
                      simulations in order to analyze the effect of voids in the
                      CRLs on the wavefront of the XFEL beam. If the distance
                      "lens to focus and sample" is large enough, the diffraction
                      patterns emerging from the voids smoothen out},
      month         = {Aug},
      date          = {2014-08-17},
      organization  = {SPIE Optical Engineering +
                       Applications, San Diego (California),
                       17 Aug 2014 - 17 Aug 2014},
      cin          = {Eur.XFEL},
      cid          = {$I:(DE-H253)Eur_XFEL-20120731$},
      pnm          = {Facility (machine) XFEL (POF2-XFEL-20130405)},
      pid          = {G:(DE-H253)POF2-XFEL-20130405},
      experiment   = {EXP:(DE-H253)XFEL(machine)-20150101 /
                      EXP:(DE-H253)XFEL-MID-20150101},
      typ          = {PUB:(DE-HGF)8},
      UT           = {WOS:000343877600002},
      doi          = {10.1117/12.2061127},
      url          = {https://bib-pubdb1.desy.de/record/206992},
}