Sub-micrometer resolution proximity X-ray microscope with digital image registration

Abstract

A compact laboratory proximity soft X-ray microscope providing submicrometer spatial resolution and digital image registration is described. The microscope consists of a laser-plasma soft X-ray radiation source, a Schwarzschild objective to illuminate the test sample, and a two-coordinate detector for image registration. Radiation, which passes through the sample under study, generates an absorption image on the front surface of the detector. Optical ceramic YAG:Ce was used to convert the X-rays into visible light. An image was transferred from the scintillator to a charge-coupled device camera with a Mitutoyo Plan Apo series lens. The detector's design allows the use of lenses with numerical apertures of NA = 0.14, 0.28, and 0.55 without changing the dimensions and arrangement of the elements of the device. This design allows one to change the magnification, spatial resolution, and field of view of the X-ray microscope. A spatial resolution better than 0.7 μm and an energy conversion efficiency of the X-ray radiation with a wavelength of 13.5 nm into visible light collected by the detector of 7.2% were achieved with the largest aperture lens.

13.5 nm Schwarzschild microscope with high magnification and high resolution

“…In 2011, Wang et al [26] used a 10× magnification, 0.1 NA Schwarzschild microscope to get better than a 3 μm mesh image on a CCD at a wavelength of 13.5 nm. In 2015, Chkhalo et al [27] described a compact laboratory proximity Schwarzschild microscope with different NAs and different magnifications at a wavelength of 13.5 nm; the best spatial resolution has gotten better than 700 nm on a CCD.…”