Neutron Diffraction Studies at the IBR2 Reactor Status and Future Geologisches Institut, Universität Freiburg, Albertstr. 23b, Freiburg, Germany J.H. Behrmann

Status and Future Experimental facilities available Experimental facilities available Possible ventures into new equipment Possible ventures into new equipment Examples of current studies Examples of current studies Future experimental activities Future experimental activities

SKAT - Neutron texture diffractometer Experimental facilities:

Parameters of SKAT Total flight path (moderator – detector) m Range of wavelengths 0.8 ~ 7.6 Å Range of d-spacings0.6 ~ 5.6 Å Detectorsup to 21 3 He single tube, Ø: 60mm, unique scattering angle 2  =90° Collimatorstwo sets of Gd-coated soller collimators, angular dispersion: 18’ and 45’, cross section: 55 x 55 mm Resolution  d/d ~ 0.55 % at d =2 Å(18’ collimation) ~ 0.7 % at d = 2 Å (45‘ collimation) Beam cross section50 x 85 mm Typical sample volume20 ~ 50 cm 3 Experiment controlVME-based measuring system running OS-9 and X WINDOW

Main advantages of SKAT low absorption of neutrons in matter: large sample volumes accessible low absorption of neutrons in matter: large sample volumes accessible TOF: complete diffraction patterns can be recorded TOF: complete diffraction patterns can be recorded application of multiple detectors: measurements are fast application of multiple detectors: measurements are fast excellent spectral resolution: suitable for polyphase geological samples with many diffraction lines excellent spectral resolution: suitable for polyphase geological samples with many diffraction lines unique scattering angle 2  of all detectors: minimum of intensity corrections required unique 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 EPSILON Excellent spectral resolution because of long flight path (> 100 m) Excellent spectral resolution because of long flight path (> 100 m) Intensity gain by operation of radial collimators and multi- detector system Intensity gain by operation of radial collimators and multi- detector system Simultaneous detection of nine different directions on Debye-Scherrer cone offers possibility for strain tensor estimations Simultaneous detection of nine different directions on Debye-Scherrer cone offers possibility for strain tensor estimations Detection of lattice strains by Bragg peak shift and broadening Detection of lattice strains by Bragg peak shift and broadening Uniaxial pressure device (max. load 150 MPa) for in situ deformation of samples Uniaxial pressure device (max. load 150 MPa) for in situ deformation of samples Laser extensometer for in-situ determination of macroscopic sample strain Laser extensometer for in-situ determination of macroscopic sample strain Temp. cabin for thermal stability (  T = +/- 0.5 K) Temp. cabin for thermal stability (  T = +/- 0.5 K)

Possible ventures into new equipment Construct 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 rocks quartz single crystals

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

Comparison of texture-induced and microcrack-induced Vp anisotropy Texture-induced, quartzite, Naxos microcrack-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 Earth´s crust

Residual lattice strains in crystals and rocks

Bragg peak shift as residual lattice strain indicator

Future experimental activities Future projects should either contain a component of instrument development, to be carried out when reactor is being reconstructed Future 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 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 address fundamental questions in applied geo- materials research or emphasize on development of novel methods of data analysis or emphasize on development of novel methods of data analysis

Expressions of interest Rock anisotropy Rock anisotropy - elastic (Behrmann, Freiburg; Kern, Kiel; Nikitin/Ivankina, Dubna) - thermal (Siegesmund, Göttingen) - magnetic (de Wall, Würzburg) - strain state (Frischbutter, Potsdam) Texture for kinematic analysis Texture for kinematic analysis - (Kroner, Freiberg; Behrmann, Freiburg) Mathematical background (Schaeben, Freiberg; Nikolayev, Dubna) Mathematical background (Schaeben, Freiberg; Nikolayev, Dubna)