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New method for focusing x rays and gamma rays

1982; American Institute of Physics; Volume: 53; Issue: 2 Linguagem: Inglês

10.1063/1.1136941

1527-2400

R. K. Smither,

X-ray Diffraction in Crystallography

A new method for focusing x rays and gamma rays is described that can focus monochromatic radiation from a point source or parallel beam down to a line image. If two focusing elements are used or if a single element bent in two directions is used, the radiation can be focused to a point image. Conversely, radiation from a point source can be converted into a parallel beam. The method makes use of bent diffraction crystals in which the intercrystalline-plane spacing is varied as a function of position in the crystal. The Bragg angle for diffraction of monochromatic radiation will now vary as a function of position in the crystal, and this new degree of freedom can be used to obtain focusing of the diffracted beam. A number of ways to achieve this variation in crystal-plane spacing is discussed, including the use of thermal gradients and the variation of the elemental composition of the crystal. The applications of this new focusing system to a gamma-ray telescope and to the production of a real image of a strong x-ray source are considered.