Element sensitive holographic imaging of atomic structures using white x rays

Abstract

White-beam x-ray fluorescence holograms were recorded using a 50 watt x-ray tube for a Cu 3 Au single crystal. Element sensitivity for this model sample was explicitly demonstrated by measuring distinct holograms using Cu K and Au L x-ray fluorescence. The phase sensitivity of the recorded holograms enabled us to obtain projections of the local atomic structure and image the electron density within the unit cell, relative to either Au or Cu atoms. Since the experimental setup does not require any optics and the angular resolution requirements are loose, the application of more powerful laboratory x-ray sources is straightforward.

X-ray fluorescence holography studies for a Cu3Au crystal

“…6(c and d). The quality of the holographic signal is high and the signal-to-noise is even higher than for the white-beam holograms recently recorded for the same sample [9]. The most apparent features visible in (a-d) are sharp lines corresponding to diffraction from atomic planes.…”

“…Simultaneously Cu 3 Au crystals have been frequently used as model samples for testing the capabilities of XFH [9,[14][15][16]. In the ordered L1 2 phase, at lower temperatures, both Cu and Au atoms occupy well defined positions as shown in Fig.…”

“…Synchrotron radiation is also required for performing multi-energy experiments which enable to eliminate holographic twin-images [6,7]. However, in recent works we demonstrated that XFH experiments in laboratory conditions are feasible and experimental setups utilizing white or monochromatic X-rays provide sufficient intensity to perform studies on some fundamental properties of XFH [8][9][10].…”

X-ray holography

“…The presence of a characteristic`shadow' in the direction of primary radiation propagation becomes its main feature (Fig. The`shadow effect' allows directly observing the signal variation in the directions coinciding with the directions of dense atomic packing and with atomic planes [185]. The`shadow effect' allows directly observing the signal variation in the directions coinciding with the directions of dense atomic packing and with atomic planes [185].…”

Matrix effects in white-beam X-ray fluorescence holography

“…Similarly to its monochromatic counterpart, white-beam XFH (Korecki et al, 2011;Dą browski et al, 2013) provides local atomic structure information. The usage of polychromatic X-rays significantly changes the nature of the holograms.…”