Focusing high-energy x rays by compound refractive lenses

TLDR

The study discusses manufacturing technologies and potential applications for the proposed compound refractive lenses. The authors propose using low‑Z material compound lenses arranged in a linear array to achieve sub‑micrometer focusing of high‑energy x‑rays (>5 keV) in one or two dimensions. They present a focusing theory based on Maxwell’s equations and the Fresnel–Kirchhoff approach and fabricate the lenses by drilling 200 0.5‑mm holes into an Al block for linear focusing and two crossed arrays of 100 holes each for point focusing. At 30 keV the linear lens produced a 3.7‑µm spot and the two‑dimensional lens produced an 8‑µm × 18‑µm spot.

Abstract

Compound lenses made from low-Z materials (e.g., Be, B, C, and Al) set up as a linear array of refractive lenses are proposed for submicrometer focusing of high-energy x rays (>5 keV) in one or two dimensions. A theory of focusing based on Maxwell's equation and the Fresnel-Kirchhoff approach is presented. Compound refractive lenses were manufactured by drilling into an Al block a linear array of 200 closely spaced holes 0.5 mm in diameter for linear focusing and two crossed arrays of 100 holes each for point focusing. Focal spots of 3.7 mum and 8 mum x 18 mum were obtained at 30 keV for linear and two-dimensional lenses, respectively. Different technologies of manufacturing and possible applications of the proposed lenses are discussed.