Michel Schlenker

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We used quantitative phase tomography with synchrotron radiation to elucidate the 3D structure of Arabidopsis seeds in their native state. The cells are clearly distinguished, and their internal structure is revealed through local variations in electron density. We visualized a 3D network of intercellular air space that might allow immediate gas exchange(More)
Phase objects are readily imaged through Fresnel diffraction in the hard x-ray beams of third-generation synchrotron radiation sources such as the ESRF, due essentially to the very small angular size of the source. Phase objects can lead to spurious contrast in x-ray diffraction images (topographs) of crystals. It is shown that this contrast can be(More)
Fractional Talbot images of optical gratings acting as periodic phase objects have been obtained by use of x rays of 0.069-nm wavelength from a third-generation synchrotron radiation source. Quantitative evaluation of the data obtained as a function of defocusing distance provides information on the lateral coherence of the beam as well as on the phase(More)
The Talbot effect is the self-imaging, at distances D multiple of D(R), of the intensity downstream of a periodic object. Earlier work with hard synchrotron radiation X-rays showed the variation with D of the fundamental Fourier component of intensity to be a good measurement of beam coherence. Any higher-order Fourier coefficients I (D, m > 1) would be(More)
The lateral coherence length is of the order of 100 micron at the 'long' (145 m) ID19 beamline of the ESRF, which is mainly devoted to imaging. Most of the optical elements located along the X-ray path can thus act as ;phase objects', and lead to spurious contrast and/or to coherence degradation, which shows up as an enhanced effective angular size of the(More)
Several hard X-rays imaging techniques greatly benefit from the coherence of the beams delivered by the modern synchrotron radiation sources. This is illustrated with examples recorded on the 'long' (145 m) ID19 'imaging' beamline of the ESRF. Phase imaging is directly related to the small angular size of the source as seen from one point of the sample(More)
2014 The magnetization distribution in sputtered random-anisotropy TbCo3 amorphous films was observed by transmission electron microscopy at room, low and high temperature. In the as-grown films, about 8 x 10-8 m thick, a disordered structure on a scale of 10-7 m, consistent with the Imry and Ma picture for a correlated spin glass, is observed at room(More)
2014 We have carried out the first observation of spiral spin or chirality domains, in a single crystal of terbium in its helimagnetic phase, by polarized neutron diffraction topography. The different domain structures observed are a function of the thermal history of the sample. When the sample is warmed from the ferromagnetic phase one observes stripe(More)
Hard X-ray radiography and tomography are common techniques for medical and industrial imaging. They normally rely on absorption contrast. However, the refractive index for X-rays is slightly different from unity and an X-ray beam is modulated in its optical phase after passing through a sample. The coherence of third generation synchrotron radiation beams(More)
The domain structure of single-crystal (110) plates of 2.4 wt % silicon-iron was investigated under tensile stress parallel to [IT01 by means of the Kerr technique and of Lang's method of transmission X-ray topography. It was possible, by using both section and traverse topographs, to gain information about the lattice distorsions, and therefore the domain(More)