TY  - CONF
AU  - Roth, Thomas
AU  - Helfen, Lukas
AU  - Hallmann, Joerg
AU  - Samoylova, Liubov
AU  - Kwaśniewski, Paweł
AU  - Lengeler, Bruno
AU  - Madsen, Anders
A3  - Morawe, Christian
A3  - Goto, Shunji
A3  - Khounsary, Ali M.
TI  - X-ray Laminography and SAXS on Beryllium Grades and Lenses and Wavefront Propagation through Imperfect Compound Refractive Lenses
VL  - 9207
M1  - PUBDB-2015-01039
T2  - Advances in X-Ray/EUV Optics and Components IX
SP  - 920702-1 -- 920702-12
PY  - 2014
AB  - 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
T2  - SPIE Optical Engineering + Applications
CY  - 17 Aug 2014 - 17 Aug 2014, San Diego (California)
Y2  - 17 Aug 2014 - 17 Aug 2014
M2  - San Diego, California
LB  - PUB:(DE-HGF)8
UR  - <Go to ISI:>//WOS:000343877600002
DO  - DOI:10.1117/12.2061127
UR  - https://bib-pubdb1.desy.de/record/206992
ER  -