Neutron Diffraction Studies at the IBR2 Reactor Status and Future Geologisches Institut,...

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  • Neutron Diffraction Studies at the IBR2 ReactorStatus and FutureGeologisches Institut, Universitt Freiburg, Albertstr. 23b, 79104 Freiburg, GermanyJ.H. Behrmann

  • Status and FutureExperimental facilities available

    Possible ventures into new equipment

    Examples of current studies

    Future experimental activities

  • SKAT - Neutron texture diffractometerExperimental facilities:

  • Parameters of SKAT

  • Main advantages of SKATlow absorption of neutrons in matter: large sample volumes accessibleTOF: complete diffraction patterns can be recordedapplication of multiple detectors: measurements are fastexcellent spectral resolution: suitable for polyphase geological samples with many diffraction linesunique scattering angle 2 of all detectors: minimum of intensity corrections required

  • Polyphase rock sample: calcite + quartz +/- dolomite

  • EPSILON - Experimental facilities:

  • Parameters of EPSILON

  • Main advantages of EPSILONExcellent spectral resolution because of long flight path (> 100 m)Intensity gain by operation of radial collimators and multi-detector systemSimultaneous detection of nine different directions on Debye-Scherrer cone offers possibility for strain tensor estimationsDetection of lattice strains by Bragg peak shift and broadeningUniaxial pressure device (max. load 150 MPa) for in situ deformation of samplesLaser extensometer for in-situ determination of macroscopic sample strainTemp. cabin for thermal stability (DT = +/- 0.5 K)

  • Possible ventures into new equipmentConstruct new neutron guide (curved)

    Achieve approx. 10x increase in available proportion of thermal neutrons

  • Examples of current studies

  • Anisotropic thermal expansion of rocks/minerals,Fabric destruction of building stones by weathering

  • Bent marble facade panels

  • Compressional wave velocity anisotropy in rocksquartz single crystals

  • Texture-related compressional wave anisotropy in Quartzites, Naxos Island, Greece

  • Comparison of texture-inducedand microcrack-induced Vp anisotropyTexture-induced,quartzite, Naxosmicrocrack-induced,quartz-rich gneiss,Austrian Alps

  • Studies of relation between textures and acoustic anisotropy are vital for the understanding of seismic reflectors in the deep Earths crust

  • Residual lattice strains in crystals and rocks

  • Bragg peak shift as residual lattice strain indicator

  • Future experimental activitiesFuture projects should either contain a component of instrument development, to be carried out when reactor is being reconstructed

    or have close relation to measurement of other physical properties of geo-materials (elastic, plastic, magnetic, thermal, strain state), not using neutron radiation

    or address fundamental questions in applied geo-materials research

    or emphasize on development of novel methods of data analysis

  • Expressions of interestRock anisotropyelastic (Behrmann, Freiburg; Kern, Kiel; Nikitin/Ivankina, Dubna)thermal (Siegesmund, Gttingen)magnetic (de Wall, Wrzburg)strain state (Frischbutter, Potsdam)

    Texture for kinematic analysis(Kroner, Freiberg; Behrmann, Freiburg)

    Mathematical background (Schaeben, Freiberg; Nikolayev, Dubna)