During the early 1980s, geoscientists worldwide realized synchrotron radiation was a highly valuable tool for in situ experiments, i.e., experiments under simulated Earth mantle conditions. MAX80 at Deutsches ElektronenSYnchrotron (DESY) – HAmburger SYnchrotron LABor (HASYLAB), Hamburg, a single-stage multianvil DIA system at a synchrotron beam line was among the high-pressure pioneer apparatus designed in Japan. MAX80 is equipped to perform ultrasonic interferometry in conjunction with synchrotron radiation measurements, i.e., X-ray diffraction (XRD) and X-radiography. The maximum conditions are ∼12 GPa at 2000 K. To make transition-zone conditions accessible and to achieve bigger specimen volumes, the sister apparatus MAX200x, a double-stage DIA system, was recently installed at the HASYLAB HARWI-II beam line. MAX2000x is designed to reach 25 GPa and 2400 K, simultaneously. MAX200x is driven by a hydraulic ram with a maximum load of 1750 tons. Derived from the successful equipment of MAX80 and adapted to the new task, MAX200x is equipped for XRD with a Ge-solid-state detector, for transient ultrasonic interferometry, and it has a radiography system to measure change of volume and shape of the sample under in situ conditions. A stepper motor–driven slits system allows the X-ray beam size and shape to be optimized for experiments. Parallel to the installation of MAX200x, some experiments were carried out to improve the potentials of multianvil apparatus in terms of maximum pressure and limitation of stress inside the sample and the anvils. Some recent results of these experiments as well as the data from the first experiments with the new double-stage system are reported here.

We present a new technique for X-ray microtomography under high pressure. By modifying an opposed-anvil high-pressure cell known as the Drickamer cell, monochromatic X-ray radiographs can be collected through the entire cell assembly and a thin-walled containment ring. We designed a rotation mechanism to rotate the Drickamer cell from 0 to 180° under hydraulic load, and examined pressure-generation efficiencies of the Drickamer cell up to 8 GPa at room temperature using the energy-dispersive technique through the containment ring, which allowed us to conduct a detailed evaluation of effects of geometric factors of the Drickamer anvils for tomography application. The maximum attainable load supported by the containment ring is proportional to the anvil diameter. Cells with larger anvil diameters are less pressure efficient, although they can reach higher pressures with much higher loads. Pressure efficiency generally increases with the tapering angle and decreases with tip diameter of the anvils. However, cells with larger tapering angles are more unstable, causing blowouts beyond a certain pressure. We evaluated the quality of X-ray images using the optical setup for conventional tomography at the GSECARS (GeoSoilEnviroCARS [Consortium for Advanced Radiation Sources]) beam line, the Advanced Photon Source. Noise level in the images depends on the material used for the containment ring. Containment rings made of either cubic boron nitride or silicon carbide allow us to better observe the images, but these materials are brittle and prone to mode-1 failure and are not suitable for high-pressure generation. The noise level of aluminum-alloy rings is somewhat higher, but the material is much more ductile, and hence it is capable of supporting higher loads. Using the aluminum-alloy containment ring, we conducted a commissioning run of tomography up to 3 GPa. We demonstrate that the high-pressure tomography setup is useful for studying internal structure of objects and density of melt and fluid under pressure.