Monochromatic Kirkpatrick–Baez microscope combining a spherically bent crystal and a multilayer mirror

Abstract

Most Kirkpatrick–Baez (KB) microscopes for imaging monochromatic laser-produced plasma are composed of two concave multilayer mirrors; their energy resolution (ΔE/E) is approximately 1×10−1. In this study, a new type of monochromatic KB microscope combining a spherically bent crystal and a multilayer mirror was developed. As the spherically bent crystal features a narrow spectral bandwidth, it can attain a high energy resolution. In addition, the grazing incidence angle on the crystal is significantly larger than that on a multilayer mirror; therefore, a large collection solid angle and a high spatial resolution can be achieved. A prototype consisting of a spherically bent mica crystal and a mirror coated with Ni/C multilayers was constructed to demonstrate the feasibility and performance of the proposed KB microscope. In the backlight imaging experiment performed, the microscope achieved a spatial resolution of approximately 10μm throughout a 200μm field of view at 4.51 keV, with ΔE/E = 4.9 ×10−3. The proposed KB microscope featuring a high energy and spatial resolution is expected to be a novel experimental tool for inertial confinement fusion (ICF) diagnostics.