HR: 15:25h
AN: MR53A-08    [Abstracts]
TI: DTF-Ultrasonic Interferometry and Standard-Free Pressure Measurement in Multi-Stage Multi- Anvil Devices
AU: * Mueller, H J
EM: Hans-Joachim.Mueller@gfz-potsdam.de
AF: GFZ Potsdam in der Helmholtz-Gemeinschaft, Dept. 5, Telegraphenberg, Potsdam, D- 14473, Germany
AU: Schilling, F R
EM: fsch@gfz-potsdam.de
AF: GFZ Potsdam in der Helmholtz-Gemeinschaft, Dept. 5, Telegraphenberg, Potsdam, D- 14473, Germany
AU: Lathe, C
EM: Christian.Lathe@desy.de
AF: GFZ Potsdam in der Helmholtz-Gemeinschaft, Dept. 5, Telegraphenberg, Potsdam, D- 14473, Germany
AB: A promising way to increase the maximum pressure of multi-anvil devices is "multi-staging", i.e. implementing an additional set of "sub-anvils" between anvils and sample resulting in a better distribution and limitation of the stress inside the anvils. Contrary to the common opinion of overshooting the maximum crushing strength most of the anvils fail in high pressure experiments due to the exceeding of the maximum tensile stress as a result of the lateral deformation. Utsumi et al., 1986 published a technique to reach 60 GPa pressure by using sintered diamond anvils as second stage in a single-stage DIA-type multi-anvil apparatus. Li, 2001 published a peak pressure of more than 26 GPa for a single-stage DIA even though the diamond anvils had been broken. Wang & Utsumi, 2005 (pers. comm.) reported similar experiments performed in a deformation-DIA (D-DIA). Our experiments with two LVP's installed at DESY-HASYLAB also showed more than a pressure doubling in comparison to the original single-stage and double-stage configurations, i.e. 25 GPa at MAX80 and nearly 50 GPa at MAX200x (Mueller et al., 2006, 2007). The first ultrasonic experiments in this configuration were performed at MAX80. The top sub-anvil was acoustically coupled to the upper anvil equipped with a triple-mode ultrasonic transducer by a platinum disk of the same diameter as the cylindrical shaft of the sub-anvil. From acoustical point of view the travel path has 3 buffer rods - top MAX80 anvil, platinum disk, upper internal opposed anvil - and the bottom internal opposed anvil as reflector. As a result of preparatory experiments we had found the upper cut-off frequency for the existing transducer-TC-anvil system at about 320 MHz. An excitation function representing the bandwidth of 100 to 300 MHz was calculated and used in the data transfer function (DTF) ultrasonic interferometry experiment. NaCl was simultaneously used as pressure calibrant, using the EoS of Decker (1971), and sample for ultrasonic interferometry (Mueller et al., 2003, 2005). The compressibility results, derived from the ultrasonic data, were compared with data of static compression experiments up to 5 GPa (Bridgman, 1940) and up to 30 GPa (Birch, 1986) using experimental data from Boehler & Kennedy (1980) and Fritz et al. (1971).
UR: http://www.gfz-potsdam.de
DE: 3909 Elasticity and anelasticity
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
DE: 3994 Instruments and techniques
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting