Properties of focusing glass-capillary concentrators of soft x-ray radiation

Theoretical and experimental investigations were made of the properties of glass-capillary concentrators of soft x-ray radiation designed to transport and focus this radiation from sources with a small emitting region. The transmission coefficients of the capillaries operating in the range 0.6 < λ < 5.1 nm were calculated for glasses of different chemical compositions and a fixed angle of bending of the capillary. The efficiency ν of concentration of the 0.3 < λ < 5.1 nm radiation and the optimal radiation entry angle Ψ, ensuring maximum ν, were also calculated. The values of ν for a concentrator of x-rays from a plasma source, determined experimentally in the range 0.4 < λ < 1.0 nm, were in satisfactory agreement with the theoretical predictions. A strong dependence of the parameters of glass-capillary concentrators on the chemical composition of the glass was observed even at impurity concentrations as low as 3% — 4%.