• journal_title：American Mineralogist
• Contributor：Anton Shatskiy ; Yuriy M. Borzdov ; Konstantin D. Litasov ; Eiji Ohtani ; Alexander F. Khokhryakov ; Yuriy N. Pal’yanov ; Tomoo Katsura
• Publisher：Mineralogical Society of America
• Date：2011-
• Format：text/html
• Language：en
• Identifier：10.2138/am.2011.3643
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：96
• issue：4
• firstpage：541
• section：Articles

Pressless split-sphere apparatus (BARS) equipped with an 8-6 type multi-anvil system is used extensively for large (6 carats) gem quality diamond crystal growth and various mineralogical and geochemical studies at shallow mantle conditions (P ≤ 7.5 GPa). In this study, we extend the pressure range for this apparatus to the conditions of the Earth’s transition zone (P = 20 GPa) using a 6–8 multi-anvil system. A scaled-up Kawai-cell consisting of 47 mm WC cubic anvils with 10 mm truncation and 18 mm MgO pressure medium was employed for the experiments. A 300 mm spherical multi-anvil block compressed by a hydraulic system with 2500 atm capacity was used to compress the Kawai-cell. A pressure of 15.5 GPa was successfully generated at the oil pressure of 1875 atm. The comparison of the BARS apparatus calibrations with those obtained using a uniaxial split-sphere press USSA-5000 suggests that pressure up to 17 and 20 GPa in compressed cell/sample volumes of 1200/60 and 400/18 mm³, respectively, can be generated using a combination of the BARS apparatus and the scaled-up Kawai-cell. This cell volume is much larger than that in conventional multi-anvil systems, which does not exceed 80 mm³ at the same conditions.