The imaging x-ray telescope (IXT) was first developed at the Institute of Precision Optical Engineering of Tongji University in 2007. Since then, we have made great progress on the development of mirror fabrication, coatings, and optic assembly. In this paper, we intend to provide an overview of the progress. Currently, we can routinely produce cylindrical mirror substrates with angular resolution of 30″ to 60″. To improve the effective area, coatings using C, Ni, and Pt layers were designed and achieved a high reflectivity at 0.5 to 10 keV. During the optic assembly, an in-situ measurement system and a three-dimensional ray-tracing program have been developed, thus guiding the assembly process in real time. Several prototypes have been fabricated, and one of them with 21 mirror layers was calibrated at the MPE PANTER x-ray test facility in Germany. The IXT prototype, with a focal length of 2052.5 mm, is characterized by a measured half-power diameter of 111″ and effective area of 39  cm² at 1.49 keV.

Characterized by a high resolution, high throughput (large effective area), and large field of view, the Wolter-I microscope is the main grazing incidence imaging device for x-rays and neutrons. It is necessary to estimate the tolerance of surface deformation to achieve the required resolution in typical applications. Traditional tolerance estimation method based on Monte Carlo method required a large random sampling in a given sampling area and has a low efficiency. We derived the transverse ray aberration equations to investigate the image quality degradation caused by principal figure and alignment errors and proposed a line fitting tolerance estimation method. Finally, the figure and alignment error tolerances of a Wolter-I microscope are discussed.

Driven by the growing demand for large-size x-ray mirrors used in synchrotron radiation and free-electron laser facilities, a linear deposition system based on magnetron sputtering technique is built. The layer growth quality and thickness uniformity are optimized by adding masks in front of the cathode to reduce the oblique-incidence particles and tune the sputtering flux distribution. Based on this, a 0.5-m-length W/Si multilayer mirror is demonstrated. The multilayer has a d-spacing of 3 nm and a bilayer number of 60. The surface roughness of the multilayer is only 0.33 to 0.25 nm in the spatial frequency range of 3.0  ×  10^−  3 to 1.0  μm^−  1, and the average interface width is 0.32 nm. The hard x-ray reflectivity and uniformity of the large mirror were characterized at the Optics Beamline in Shanghai Synchrotron Radiation Facility. A maximum reflectivity of 62.5% and 62.7% was measured at 8 and 18 keV, respectively, with an angular resolution of Δθ  /  θ  =  2.7  %  . The d-spacing uniformity over the 0.5-m-length and 60-mm-width area of the mirror is 1.0% and 1.2% (peak-to-valley), respectively. These results indicate a good and uniform quality of the nanoscale multilayer over the large mirror area. The measured second- and third-order reflectivities of the multilayer are more than 2 orders magnitude lower than the first order, implying a good suppression of high harmonics in the monochromator application.