Fabrication of Ag/C multilayer zone plates for X-ray

Accompanying the practical use of powerful, good quality x-ray sources, such as synchrotron radiation and laser-excited plasma X-ray, the researches utilizing the X-ray of various wavelengths have been carried out. The X-ray of about 1A wavelength has been utilized for the analysis of the crystalline structure of matters, the analysis of defects, the observation of bio-specimens, and various analyses, and aiming at making it into microbeam, various optical elements such as zone plates, multilayer film reflection mirror, oblique incidence reflection mirror and so on were developed. In the zone plates for X-ray region, since the large aspect ratio is required, those are made by the technology of making multilayer thin films, but submicron beam size has not been obtained with them. In this report, the results of the light-collecting test on the multilayer zone plate that the authors made are shown, and the experimental results of smoothing zone are described. As the result of having made four kinds of the concentric circle multilayer films for zone plates so far, it was found that Ag/C multilayer films possess the smoothest zones and surfaces. The Ag/C multilayer zone plate with 50 layers was made, and the light-collecting test was carried out at the BL-BC experimental station of National Laboratory for High Energy Physics. The experiment and the results of the electron microscopic observation of the multilayer film and the stress measurement for the films are reported. (K.I.)