Two-step hard X-ray focusing combining Fresnel zone plate and single-bounce ellipsoidal capillary.
A two-step focusing set-up combining a Fresnel zone plate with an ellipsoidal capillary is presented. It is shown that, in addition to the anticipated gain in flux, the employment of the prefocusing micro-optic makes optimal use of the elliptical shape of the capillary by almost eliminating aberrations. A small cross section of the prefocused beam allows a tiny fraction of the capillary surface to be selected, thus reducing the influence of slope errors. An X-ray beam with a 15 keV energy was focused down to a spot size as small as 250 nm, demonstrating the best value that has been achieved up to now for single-bounce capillaries. The use of an ellipsoidal capillary as a micromirror under off-axis illumination by microfocusing optics may open up new opportunities in nanofocusing developments.
Snigirev
A
A
European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble, France.
Bjeoumikhov
A
A
Erko
A
A
Snigireva
I
I
Grigoriev
M
M
Yunkin
V
V
Erko
M
M
Bjeoumikhova
S
S