<title>Principal possibilities of Kumakhov lenses</title>

Abstract

In the last ten years there appeared a new branch of x-ray optics which was named capillary optics. New optics widely uses the possibility of controlling x-rays during their transmission through systems of bent hollow glass capillaries. Main elements of new optics are concentrating devices which got the name "Kumakhov lenses" . Different types of Kumakhov lenses can be used for solving various problems: focusing radiation onto a small spot, forming quasiparallel beams, filtering radiation, reducing or increasing x-ray images etc. The possibility of controlling x-rays is based on the phenomenon of total external reflection which takes place only at grazing incidence angles. But Kumakhov lenses have large angular aperture because they operate on multiple reflect ions.In this work we investigate the properties of Kumakhov lenses operating on multiple reflections as well as more simple capillary systems which can also focus x-rays but operate mainly on single reflections. The latter systems are capillary structures which have straight hollow mutually parallel channels. Channels may be of different form, for example circular, square or hexagonal.Keywords: Kumakhov lens, x-ray beams, radiation focusing k. MULTIPLE REFLECTIONS SYSTEMS Proposed by M. A. Kuinakhov systems [ 1 , 2] based on the phenomenon of multiple total x-ray external reflection are called Kuinakhov lenses and use for x-ray beams transformation: divergent beam into quasiparallel beam -widening semilens (Fig.la); quasiparallel beam into convergent beam -narrowing semilens (Fig. ib); divergent beam into convergent beam -lens (Fig. ic).Some more intricate modifications of these devices are possible, e.g,such as three-sectional lens consisting of two semilenses with different curvature radii and a straight section smoothly connecting them in the middle (Fig. id). M.A.Kumakhov proposed also certain schemes of total external reflection for getting x-ray filters [3].Geometry of these devices (length L, focal distance F, minimum and maximum cross-section diameters D1 and D2 -see Fig.1) is mainly determined by 2 factors: by demands to the sizes and focal distance of a lens determined from experimental conditions and demands to the lens transmission, focal spot size and final beam angular divergence.The fulfillment of the second group of conditions can be obtained only in case if all lens capillaries (both central and peripheral) take part in beam forming. Because of the fact that peripheral capillaries turn radiation to larger angles (e.g., in case corresponding to Fig. ic this angle is 2'p) x-ray 200 / SPIE Vol. 2278 X-Ray and UV Detectors (1994) 0-8194-1602-9/94/$6.O0 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/03/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

Reconstruction of Thickness and Composition of Stratified Materials by Means of 3D Micro X-ray Fluorescence Spectroscopy

“…The decrease to smaller energies can be explained by the decrease of reflectivity of the glass capillaries with lower energies. The decrease to higher energies is due to large losses at the capillary entrance, because of the decreasing critical angles for total reflection …”

Focusing Polycapillary Optics and Their Applications

“…Early work at CXO [16][17][18][19][20][21] and IROS [22][23][24][25] was concerned with developing techniques for systematic measurements and of investigating the potential for application development. In 2001, Gibson retired from the university and moved to XOS.…”

<title>Concentration of synchrotron radiation with capillary arrays</title>

“…Analysis of ratio (2) shows that the degree of the beam contraction depends on the cone length L and it always meets the condition: d1/d2…”