We have fabricated and tested short focal-length compound refractive lenses (CRLs) composed of micro-bubbles embedded in epoxy. The bubbles were formed in epoxy inside glass capillaries. The interface between the bubbles formed 90 to 196 spherical bi-concave microlenses reducing the overall focal length inversely by the number of lenses.
When compared with CRLs manufactured using other methods, the micro-bubble lenses have shorter focal lengths, better imaging, and focusing qualities with higher transmissions and gains for moderate energy x-rays (e.g. 7 - 12 keV). We used beamline 2-3 at the Stanford Synchrotron Radiation Laboratory (SSRL) to measure focal lengths between 100-150 mm and absorption apertures between 90 to 120 μm. Transmission profiles were measured giving, for example, a peak transmission of 27 % for a 130-mm focal length CRL at 8 keV. The focal-spot sizes were also measured yielding, for example, an elliptical spot of 5 x 14-μm2 resulting from an approximate 80-fold demagnification of the 0.44 x 1.7 mm2 source. The measured gains in intensity over that of unfocused beam were between 9 and 26. Theoretical gain calculations that include spherical aberrations show that these values are reasonable. The micro-bubble technique opens a new opportunity for designing lenses in the 8-9 keV range with focal lengths less than 30-40 mm.
Refractive microcapillary lens for hard x-rays is presented. The lens is designed as glass capillary filled by a large number of biconcave microlenses. Fabrication technique for the lens is described. It is shown that the the microlenses have a spherical shape. The spherical aberrations of the lens are calculated. The possibility of production of micrometer sized x-ray beams by using the microcapillary x-ray lens is discussed.
We developed and studied refracting microcapillary lens for x-ray photons with energy 5.4 keV. This lens is a glass capillary wiht a central channel filled with a number of concave microlenses. The lenses are made by injection compressed air into a capillary channel, previously filled by liquid polymer. The images of 20-100μm width slits are obtained. A good agreement is seen betweenthe image and slits sizes. Ray tracing calculations of iamge formation are made. Experimental and calculated results are in a good agreement.
A novel experimental method is presented for evaluating the crystal lattice imperfections using a reflection X-ray microscope (RXM). An X-ray microscope using an X-ray refractive lens is constructed on the reflected beam axis of the crystal. This method has a unique advantage that the image contrast due to the integral reflectivity variation and due to the phase-contrast of the crystal surface are easily discriminated by de-focusing technique. The sample crystals chosen were silicon circular Bragg Fresnel zone places (BFZPs). The BFZPs had circular zones on Si(111) plane with two different groove depths of 3.9 micrometers and 5.9 micrometers . The validity of the de-focusing method was proved and a clear difference of the X-ray microscope images was observed for the BFZPs with different groove depth.
Refractive microcapillary lens for hard X-rays is presented. The lens is designed as glass capillary filled by a large number of biconcave microlenses. Fabrication technique for the lens is described. It is shown that the microlenses have a spherical shape. The spherical aberrations of the lens are calculated. The possibility of production of micrometer sized X-ray beams by using the microcapillary X-ray lens is discussed.