PMC

Diffraction pattern and Fourier transform of the same sample as in Figs. 3 and 4, but recorded on a CCD detector (exposure 500 ms; pixel size 150 µm). (a) Diffraction pattern; (b) Fourier transform. In (b) a pair of character images are recognized, with somewhat inferior quality (yellow arrow).

Scanning ion micrograph of the test pattern fabricated on 0.5 µm gold foil. Chinese characters meaning ‘up’ are arranged in a 5 × 5 matrix. Each character has its own reference dot on the lower left. Scale bar: 1 µm. Inset: average of the images of 25 characters (2× magnification).

Schematic diagram of X-ray optics used in the study. Upstream left; b: beamstop and aluminium mask; c: cassette for imaging plate, which allows the use of the CCD camera behind when the plate is removed; i: image intensifier and CCD camera; p: pinholes made of 50 µm tantalum. The aperture sizes are 10, 20 and 50 µm from upstream. s: sample on a motorized x–z stage; v: vacuum path. Dimensions are in mm.

Pseudocolor representation of the diffraction pattern (hologram) of the test pattern shown in Fig. 2, recorded on an imaging plate (exposure, 1 min; pixel size, 50 µm). Scattering from the plain gold foil has been subtracted and the diffraction pattern has been square-rooted to indicate the true amplitude of the structure factor. The inset on the lower left shows a magnified view of part of the diffraction pattern, showing the sampling owing to the 5 × 5 matrix. The patterns have been rotated by 10.6° to match the lattice orientation, as the lattice of the sample was not visible at the time of mounting.

Pseudocolor representation of the Fourier transform (Patterson map) of the diffraction pattern as shown in Fig. 3, after restoration of the intensities under the beamstop (see §2). Besides the pair of images of the Chinese character around the center (white arrow), additional images were created in the outer area owing to the matrix arrangement of characters. Of these only a single pair is clearly recognized (pink arrow). Others are corrupt (gray arrows). These arrows point to the short sidebar of the Chinese character. The upward pointing arrows indicate the centers of additional autocorrelation terms. Note that the vertical ones (red arrow) are brighter than the horizontal ones (green arrow). Scale bar: 1 µm.