Some Characteristics of Dynamical Diffraction at a Bragg Angle of about π/2

Köhra, Kazutake; Matsushita, Tadashi

doi:10.1515/zna-1972-0317

Cited by 65 publications

(31 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was first treated by Kohra and Matsushita. 7 More recently, the application of Bragg backscattering to lattice constants measurements was discussed by Shvyd'ko et al 8 The experimental arrangement of the present experiment is shown in Fig. 1.…”

mentioning

confidence: 82%

“…Thwelis 3 found a difference in the lattice constants of 6 LiF and 7 LiF of the order of two parts in ten thousand. Buschert et al, 4 using an x-ray spectrometer which was designed and built for high-precision measurements of lattice parameters of perfect single crystals, determined the lattice parameter of an isotopically enriched ͑95.8%͒ sample of 74 Ge of high crystal perfection, and compared with natural Ge (M ϭ72.6).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Effect of isotopic composition on the lattice parameter of germanium measured by x-ray backscattering

Sinn

Alataş

et al. 2003

Phys. Rev. B

View full text Add to dashboard Cite

mentioning

confidence: 82%

mentioning

confidence: 99%

Effect of isotopic composition on the lattice parameter of germanium measured by x-ray backscattering

Sinn

Alataş

et al. 2003

Phys. Rev. B

View full text Add to dashboard Cite

“…6 and 13 it was shown that an energy scanned XSW measurement at B ϭ/2 is much less sensitive to imperfections of the crystal because of a wide ͑of order 1°) Bragg reflection width. 14 Here it is shown that the energy dependence of the x-ray absorption at B ϭ/2 is also measured in polycrystalline samples. The elastic scattering is expected to produce a step structure at the same energy position because of appearance of a new Debye-Scherrer cone.…”

mentioning

confidence: 87%

Photon interference x-ray absorption fine structure

et al. 2001

View full text Add to dashboard Cite

We report about a fine structure in x-ray absorption spectra, named photon interference x-ray absorption fine structure (XAFS). XAFS is due to the interference of x-rays inside the sample and extends across absorption edges. Using a platinum foil XAFS was measured in a high precision absorption experiment. Excellent agreement with a theoretical XAFS simulation is achieved in the energy range for above an absorption edge where photoelectron XAFS is negligible. XAFS provides a method for determination of atomic structure on short-and long-range order scale.For photon energies up to several ten keV, x-ray absorption is for heavier elements dominantly caused by the photoionization process. Absorption edges occur as sudden jumps in the spectra, whenever the incident x-ray energy exceeds the binding energy of an inner electron of the absorbing atom. Near and above such absorption edges, the absorption coefficient exhibits an x-ray absorption fine structure ͑XAFS͒ induced by the electronic and geometrical environment of the absorbing atom. Especially the oscillatory fine structure in the region up to around 2000 eV above an absorption edge called EXAFS ͑extended XAFS͒ is widely used as a tool for structure determination. 1,2 It results from the interference of the excited outgoing photoelectron wave with its backscattered waves from neighboring atoms. In conventional formalism, the initial-state photon is assumed to be a plane wave. EXAFS measures the radial distribution of neighboring atoms, coordination numbers, and averaged phonon properties on a short-range order scale.In this paper, we discuss a fine structure in the x-ray absorption spectra which we call photon interference x-ray absorption fine structure (XAFS). In XAFS, the initial-state photon is an interference field resulting from the incident photon wave and its coherently scattered waves from neighboring atoms ͑see Fig. 1 inset͒. XAFS extends in a wide photon energy range below and above absorption edges. It is shown that XAFS carries information about the short-range order structure of the sample comparable to EXAFS. Due to a long mean-free path of a photon, XAFS is also sensitive to longer-range order. XAFS and EXAFS are caused by modification of the absorption due to the multiatom effect. The importance of the multiatom effect in coherently excited resonant photoionization to yield near-neighbor information was also pointed out in Ref. 3.For a material with long-range order the photon interference effect is well known near a Bragg condition and results in a strong change in x-ray absorption. 4 In this case the multiple scattered waves from many atoms interfere constructively and form a strong spatially modulated x-ray standing wave ͑XSW͒ field. By slightly changing the incident angle or energy, the XSW field moves in the sample, and accordingly the local x-ray intensity at the absorbing atom position changes. This effect has been intensively studied over narrow angle or energy ranges, and has been applied for structure determination. 5 XSW also explains ...

show abstract

“…The dynamical theory of diffraction predicts that at this angle the Darwin-Prins rocking curve has an extreme angular width, which typically exceeds the mosaic spread caused by strain in most metal crystals [21,22]. The coherence of the standing waves is thus maintained even in imperfect samples.…”

Section: (Received 28 August 1998)mentioning

confidence: 99%