An improved setup for radial diffraction experiments at high pressures and high temperatures in a resistive graphite-heated diamond anvil cell

Abstract

We present an improved setup for the experimental study of deformation of solids at simultaneous high pressures and temperatures by radial X-ray diffraction. The technique employs a graphite resistive heated Mao Bell type diamond anvil cell (DAC) for radial X-ray diffraction in combination with a water-cooled vacuum chamber. The new chamber has been developed by the sample environment group at PETRA III and implemented at the Extreme Conditions Beamline (ECB) P02.2 at PETRA III, DESY (Hamburg, Germany). We discuss applications of the new setup to study deformation of a variety of materials, including ferropericlase, calcium perovskite, bridgmanite, and tantalum carbide at highpressure/temperature.

Does Heterogeneous Strain Act as a Control on Seismic Anisotropy in Earth’s Lower Mantle?

“…The sample was then converted with offline laser heating by rastering the laser (20-30 μm spot size) over the sample for ∼15 min. Constraints imposed by the resistive heated-DAC sample stage do not allow online laser heating when the end station is configured for resistive heating (Liermann et al, 2009;Immoor et al, 2020). Thus, laser heating was done offline and no diffraction images were taken prior to or during conversion.…”

“…The resistive heating array (Liermann et al, 2009;Immoor et al, 2020) was assembled post-conversion, and a radial diffraction image was taken to confirm the presence of bridgmanite. The aggregate was then gradually heated to ∼1,000 K over the course of 3 h and 15 min.…”

“…Here, we report results of in situ high-temperature deformation experiments at lower mantle pressures on an aggregate composed mostly of bridgmanite and ferropericlase. Our experiments are performed using a resistive heated radial diamond anvil cell (RDAC) (Liermann et al, 2009;Merkel et al, 2013;Miyagi et al, 2013;Immoor et al, 2018;Immoor et al, 2020) that allows for a continuous and uniform heating of samples deformed at lower mantle pressures. In-situ radial X-ray diffraction records lattice strain and texture development.…”

Experimental elasticity of Earth’s deep mantle

“…4). However, as hinted above, progress is gathering pace; the pressure regime in the LVP is ever expanding, with conditions of over 100 GPa achieved using sintered diamond anvils 92 , whilst DAC-based resistive heating can now be performed up to ~ 1500 K, and possibly higher, for several hours at a time 125,126 .…”

“…The scribbled regions shows the approximate range of PT-conditions that have been reached using the respective high-PT apparatus, but where few or no elasticity measurements have been performed to-date. Green scribbled region: Conditions achievable in the MAP 92 ; blue scribbled region: Conditions achievable in the resistiveheated DAC 126 . The laser-heated DAC is capable of reproducing the entire range of PT-conditions covered by the figure.…”