a) b) 


Fig. 96: a) Experimental set-up with a curved Bragg-Fresnel lens in the white beam of BM5. b) Mapping of the focal spot of a curved linear Bragg-Fresnel lens with 1 µm pinhole paired with a PIN diode and a scintillating counter at 18 keV. In accordance with the demagnification factor and the X-ray source size, a focal spot of 2 x 5 µm2 was measured. c) Extrapolation from the measurements of BM5 to the ultimate intensity which will be obtained on ID22.