Recent development of doubly curved crystal focusing optics and their a

摘要

Abstract: Three-dimensional focusing of x-rays can be achieved by doubly-curved crystals through diffraction from a small laboratory x-ray source. Recently it has been demonstrated that an intense monochromatic x-ray microprobe can be obtained with the use of a doubly-curved mica crystal. Due to monochromatic excitation using doubly-curved crystal optics, exceptionally low background has been demonstrated in the application to micro x-ray fluorescence (MXRF). Low background and high intensity gain significantly improve the detection limit for MXRF. In this paper, the focusing and diffraction properties of a doubly-curved Johann point-focusing crystal optic for Cu K$alpha x-rays from a microfocus x-ray source is presented. Experimental data on spot size, beam intensity, effect of source position for the optics, and MXRF spectra are discussed. !6