Soft X-Ray Microscope with Zone Plates at UVSOR I: Performance

Abstract

A soft X-ray microscope with zone plates was set up at UVSOR (synchrotron radiation facility at Institute for Molecular Science, Okazaki). A 0.41 µm line-and-space pattern was clearly distinguished using an objective zone plate with the outermost zone width of 0.41 µm. Modulation transfer functions were measured at wavelengths of 3.1 nm and 5.4 nm, and compared with theoretical calculations. The experimental results corresponded fairly well with the theoretical ones, taking into account that a point spread function of a microchannel plate and fluorescent plate assembly used as a detector had a full width at half-maximum of 50 µm. A theoretical calculation of an intensity–wavelength distribution of illumination at an object plane was performed and compared with experimental results. Nonuniformity of illumination can be explained in terms of a distance between a specimen and a pinhole in front of it.