TY  - JOUR
AU  - Jafari, A.
AU  - Sergueev, I.
AU  - Bessas, D.
AU  - Roschin, B. S.
AU  - Asadchikov, V. E.
AU  - Alexeev, P.
AU  - Härtwig, J.
AU  - Chumakov, A. I.
AU  - Wille, H.-C.
AU  - Hermann, Raphael
AU  - Klobes, Benedikt
TI  - Rocking curve imaging of high quality sapphire crystals in backscattering geometry
JO  - Journal of applied physics
VL  - 121
IS  - 4
SN  - 1089-7550
CY  - Melville, NY
PB  - American Inst. of Physics
M1  - FZJ-2017-01517
SP  - 044901 
PY  - 2017
AB  - We report on the characterization of high quality sapphire single crystals suitable for high-resolution X-ray optics at high energy. Investigations using rocking curve imaging reveal the crystals to be of uniformly good quality at the level of ∼10−4 in lattice parameter variations, δd/d. However, investigations using backscattering rocking curve imaging with a lattice spacing resolution of δd/d∼5×10−8 show very diverse quality maps for all crystals. Our results highlight nearly ideal areas with an edge length of 0.2–0.5 mm in most crystals, but a comparison of the back reflection peak positions shows that even neighboring ideal areas exhibit a relative difference in the lattice parameters on the order of δd/d=10–20×10−8; this is several times larger than the rocking curve width. Stress-strain analysis suggests that an extremely stringent limit on the strain at a level of ∼100 kPa in the growth process is required in order to produce crystals with large areas of the quality required for X-ray optics at high energy.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000393480100032
DO  - DOI:10.1063/1.4974106
UR  - https://juser.fz-juelich.de/record/827388
ER  -