HR: 14:25h
AN: MR13A-04    [Abstracts]
TI: Transient Measurements Under Simulated Mantle Conditions - Simultaneous DTF-Ultrasonic Interferometry, X-Radiography, XRD
AU: * Mueller, H J
EM: Hans-Joachim.Mueller@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam Dept. 4, Telegraphenberg, Potsdam, D-14473 Germany
AU: Schilling, F R
EM: fsch@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam Dept. 4, Telegraphenberg, Potsdam, D-14473 Germany
AU: Lathe, C
EM: christian.lathe@desy.de
AF: GeoForschungsZentrum Potsdam Dept. 4, Telegraphenberg, Potsdam, D-14473 Germany
AU: Wunder, B
EM: wunder@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam Dept. 4, Telegraphenberg, Potsdam, D-14473 Germany
AB: The interpretation of seismic data from the Earth's deep interior requires measurements of the physical properties of Earth materials under experimental simulated mantle conditions. Elastic wave velocity measurement by ultrasonic interferometry is an important tool for the determination of the elastic properties in multi-anvil devices. Whereas the classical sweep method is very time-consuming, the ultrasonic data transfer function technique (DTF), simultaneously generating all the frequencies used in the experiment, first described by Li et al. (2002), requires just few seconds to save the response of the system. The success of the technique substantially depends on the excitation function and the resolution used for saving the DTF (Mueller et al., 2004a). Background discussion as well as high pressure AŸA_A,A¨A,A« high temperature results demonstrate how to optimize the technique. All Ultrasonic interferometry allows highly precise travel time measurement at a sample enclosed in a high-pressure multi-anvil device. But under high pressure conditions the influence of sample deformation on the frequencies for destructive and constructive interference used for the evaluation of the elastic properties might be stronger than that from the shift of the elastic moduli. Consequently ultrasonic interferometry requires the exact sample length measurement under in situ conditions. X-ray imaging using brillant synchrotron radiation, called X-radiography, produces grey-scale images of the sample under in situ conditions by converting the X-ray image to an optical one by a CE-YAG-crystal. Saving the optical image by a CCD-camera after redirection by a mirrow, also requires few seconds. To derive the sample length, the different brightness of sample, buffer rod and reflector at the electronic image is evaluated (Mueller et al., 2004b). Contrary to XRD measurements, imaging the sample by X-rays requires a beam diameter larger than the sample length. Therefore the fixed primary slits of Max80 were exchanged by 4-blade high precision slits of Advanced Design Consulting, Inc. Some recent results on the non-quenchable high-P AŸA_A,A¨A,A« low-P clinoenstatite transition and to the quartz-coesite transition will be given to discuss the different interferometric techniques, including the XRD-data and X-radiography results, necessary to detect the phase transitions under in situ conditions and to measure the sample deformation. Li, B.; Chen, K.; Kung, J.; Liebermann, R.C.; Weidner, D.J., J. Phys.: Condens. Matter 14, 11337-11342, (2002). Mueller, H.J.; Lathe, C.; Wunder, B., In: J. Chen, Y. Wang, T. Duffy, G. Shen, L. Dobrzhinetskaya (eds.), Frontiers in High Pressure Research, Elsevier Science, submitted, (2004a). Mueller, H.J.; Schilling, F.R.; Lathe, C.; Lauterjung, J., In: J. Chen, Y. Wang, T. Duffy, G. Shen, L. Dobrzhinetskaya (eds.), Frontiers in High Pressure Research, Elsevier Science, in press, (2004b).
DE: 8124 Earth's interior--composition and state (old 8105)
DE: 7207 Core and mantle
DE: 3909 Elasticity and anelasticity
DE: 3924 High-pressure behavior
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
SC: Mineral and Rock Physics [MR]
MN: 2004 AGU Fall Meeting