The pressure range of conventional multi-anvil apparatus is limited to 25 GPa. We try to extend this pressure range by designing a high-precision guide block system that allows to compress high-pressure assemblies with anvils harder than usual carbide. The concept of this apparatus is explained in the poster presentation shown below.

In October 2014, a new Kawai-type multi-anvil apparatus, IRIS-15, was installed in the BGI. IRIS-15 is a uniaxial press with the maximum press load of 15 MN and equipped with a DIA-type guide block system.

Images of IRIS-15. (A) Front view. and (B) the lower guide block with two sliding wedges. (1) The control of the hydraulic system, (2) the lower guide block, (3) the upper guide block, (4) the heating system,  (5) fist-stage anvils, (6) Teflon sheet，(7) two sliding wedges.

As explained in the poster on May 11, 2014, the guide block system of IRIS-15 is tunable, as is that of SPEED-Mk.II in SPring-8 [Katsura et al., 2004]. The deviation of the vertical to horizontal dimensions of the cubic compressional space of IRIS-15 is suppressed to -0.07 micron/MN, which is even smaller than that of SPEED-Mk.II, +4 micron/MN, as is shown below.

We successfully generated pressures over 40 GPa using IRIS-15. It is noted that a pressure of 44 GPa at 2000 K was generated using not sintered-diamond anvils but carbide anvils, which was confirmed by synthesis of LiNbO₃ type of Mg₃Al₂Si₃O₁₂.

Ishii, T., L. Shi, R. Huang, N. Tsujino, D. Druzhbin, R. Myhill, Y. Li, L. Wang, T. Yamamoto, N. Miyajima, T. Kawazoe, N. Nishiyama, Y. Higo, Y. Tange, and T. Katsura, Generation of pressures over 40 GPa using Kawai-type multi-anvil apparatus with tungsten carbide anvils, Rev. Sci. Instr. 87, 024501, doi: 10.1063/1.4941716, 2016.