Measurement of Point-Spread Function of IP-System

For the resolution estimation of the Imaging Plate (IP)-system, several methods were carried out. One of them is the measurement of the modulation transfer function (MTF) from the phase contrast transfer function taken with an amorphous Ge film specimen. One of another is the measurement of the point-spread function (PSF) from the auto-correlation of the Poison noise obtained by the IP-system.In this experiment, the PSF of the IP-system were measured from the intensity distribution recorded with a 1.6 μm-diameter electron probe on the IP.When recording the electron intensity with a small enough electron probe as compared with the pixel size of the IP (25 μm × 25 μm), a single pixel detects the electron signal in case of ideal IP-resolution which is limited only by the pixel size. However, practical IP-resolution is limited by the electron diffusion, x-ray emission and the laser beam diffusion in the IP, and so on. Therefore, it is possible to measure the PSF from the intensity distributions of the patterns recorded with a small enough electron probe.