2024 年 100 巻 3 号 p. 149-164
Since the large-volume press with a double-stage multianvil system was created by the late Professor Naoto Kawai, this apparatus (Kawai-type multianvil apparatus or KMA) has been developed for higher-pressure generation, in situ X-ray and neutron observations, deformation experiments, measurements of physical properties, synthesis of high-pressure phases, etc., utilizing its large sample volume and capacity in stable and homogeneous high temperature generation compared to those of competitive diamond anvil cells. These advancements in KMA technology have been made primarily by Japanese scientists and engineers, which yielded a wealth of new experimental data on phase transitions, melting relations, and physical characteristics of minerals and rocks, leading to significant constraints on the structures, chemical compositions, and dynamics of the deep Earth. KMA technology has also been used for synthesis of novel functional materials such as nano-polycrystalline diamond and transparent nano-ceramics, opening a new research field of ultrahigh-pressure materials science.
Professor Percy W. Bridgman of Harvard University, the winner of Nobel prize in physics in 1946, is referred to as the father of high-pressure physics, who devised various methods related to high-pressure generation and firstly attained pressures of 10 GPa in the 1910s.1) He used a pair of anvils or pistons, made of ultrahard materials such as hardened steel or tungsten carbide with some binders (WC, hereafter), to compress the samples between them with a uniaxial press. A variety of high-pressure apparatus with the opposed anvils1)–7) have been invented (Fig. 1), partly motivated by the quest to synthesize diamond at high pressure and temperature, some of which are even currently being used mainly in geoscience and materials science.
Schematic cross sections of various types of opposed anvil apparatus. (a) Piston-cylinder apparatus, (b) belt-type apparatus, (c) Bridgman-type apparatus, (d) Drickamer-type apparatus, and (e) diamond anvil cell. Note that the diameters of anvils in (a)–(d) are typically a few cm, while those of conventional DAC are about 3 mm.
Among these opposed anvil apparatus, diamond anvil cell (DAC), developed mainly in the U.S.A.7) using a pair of single crystal diamond anvils to squeeze the sample, firstly reached pressures of the Mbar regime (i.e., pressures above 100 GPa). DAC can currently produce pressures up to ∼400 GPa and temperatures to ∼6000 K combined with laser heating,8) which covers whole pressure and temperature ranges of the Earth’s interior, although the sample volume is extremely small and homogeneous temperature generation within the sample is very difficult. It is interesting to note that the highest static pressure was achieved with this kind of a tiny apparatus, which can be handled on one’s palm.
The first large-volume press (LVP) built for high-pressure science in Japan is probably the one designed by Professors Toshi Shida and Motonori Matuyama of Kyoto University in 1918 (Fig. 2), who are renowned for their significant contributions to discoveries of deep-focus earthquakes9) and the geomagnetic reversal,10) respectively. The press was designed to generate pressures to 2 GPa, and their original plan was to use it for studies on mechanical behaviors of rocks under such pressure. However, no documentation exists on what pressure they actually generated using this press, which was subsequently altered to use for deformation of granitic rocks.11) Nevertheless, it is interesting that the attempt to produce very high pressure was made in Japan almost at the same time when Prof. Bridgman started his work on high-pressure physics.
(Color online) A large-volume press constructed by Profs. Matuyama and Shida in 1918. The press is still intact and being exhibited at the Abuyama Observatory of Disaster Prevention Research Institute, Kyoto University. The photo was provided by Prof. T. Kondo of Osaka University.
Technology of multianvil (the number of anvils > 2) apparatus using a uniaxial LVP was created in the late 1960s in Japan, leading to various types of cubic apparatus, which compress the sample in a cubic-shaped pressure medium using six anvils. These include DIA-type,12) Link-type,13) and Wedge-type14) apparatus, which were successfully used for synthesis of diamond and other high-pressure phases up to about 8 GPa. In contrast, tetrahedral and octahedral multianvil apparatus with four and six separate hydraulic rams, respectively, were invented in the U.S.A.,2) also for the synthesis of diamond in this pressure range, and later developed in Japan for additional uses in geoscience.15)–17)
Attempts to produce further higher pressures using multianvil apparatus operated in LVP were made by Prof. Mineo Kumazawa of Nagoya University, using his highly original multiple anvil sliding system (MASS).18) The maximum pressure attained in the MASS was approximately 20 GPa‡, which was substantially higher than those reached by other high-pressure devices using LVP, except for KMA mentioned in the following. However, it failed to produce higher pressures partly due to the limitations in the strength of WC anvils and large frictions along sliding anvils to squeeze the sample and lost the competition with DAC in high-pressure generation toward the Mbar regime.
A significant development in high-pressure technology employing LVP was made by Prof. Naoto Kawai, who was a former PhD student of Prof. Matuyama, after he moved to Osaka University in 1962. Prof. Kawai used eight anvils, split from a WC sphere, whose edges were truncated to form a regular triangle plane so that the sample in an octahedral pressure medium was compressed by the WC anvils19) (Fig. 3(a)). The split sphere multianvil apparatus was claimed to have produced pressures as high as 20 GPa‡, although no suitable pressure reference was available for these pressures at that time.
Developments of Kawai-type apparatus: (a) eight anvils, split from a WC sphere with triangular truncations, compress the octahedral pressure medium in an oil reservoir. (b) A double-stage multianvil apparatus, where the octahedral pressure medium placed in the center of inner eight second-stage WC anvil cubes is compressed by six first-stage anvils, split from a steel sphere. (c) The first-stage anvils were later placed in a pair of guide blocks and squeezed in a uniaxial hydraulic press; here illustrated is the lower guide block with the first-stage and second-stage anvils.
Prof. Kawai and his colleagues then invented a double-stage multianvil apparatus, where the octahedral pressure medium placed in the center of inner eight second-stage WC anvil cubes (sometimes referred to as Kawai cell) is compressed by six first-stage anvils, split from a steel sphere, in an oil reservoir (Fig. 3(b)). The first-stage anvils were later set in a pair of guide blocks (Fig. 3(c)), and the second-stage anvils were positioned in the central cubic area and compressed with LVP,20) which significantly enhanced handling of the Kawai cell and is known as the Kawai-type multianvil apparatus, KMA21) (Fig. 4).
(Color online) Kawai-type multianvil apparatus (KMA). (a) A schematic illustration of KMA. (b) A typical KMA operated in a 2000-ton press at the Geodynamics Research Center (GRC). (c) An example of the Kawai cell with second-stage WC anvils: The central pressure medium, where the sample and furnace assembly are introduced, is surrounded by pyrophyllite gaskets. Thermocouple wires across the pressure medium are also seen.
Prof. Kawai constructed a huge LVP with a capability of applying up to 15,000 tons to produce Mbar pressure. One of his scientific goals was to realize metallization of hydrogen, which was believed to happen at pressures of the Mbar regime, but the pressure reached using KMA was limited to around 20 GPa‡ at that time. KMA technology was transferred and developed in other Japanese universities, particularly in the University of Tokyo, Nagoya University, and Okayama University in 1970s, and then exported overseas to the U.S.A., Canada, Australia, and Germany. Since then, several versions of KMA have been developed, including those with split cylinder-type guide blocks22) and the “Walker-module”,23) and disseminated globally. DIA-type press and six-axis press have also been adopted to compress the Kawai cell, particularly for use of sintered diamond with some binders (SD, hereafter) as the second-stage anvils.
Here, the author reviews the development of KMA technology toward higher-pressure generation, as well as for precise measurements of phase transitions and physical properties of high-pressure phases combined with synchrotron X-ray and neutron beams, since the first paper on KMA was published in Proceedings of the Japan Academy just 50 years ago.20) Developments in KMA technology for the synthesis of novel polycrystalline bulk materials, such as nano-polycrystalline diamond and transparent nano-ceramics, are also summarized in this article. More in-depth and thorough analyses on the history of multianvil apparatus are available elsewhere,24),25) and the author concentrates here on recent developments in KMA technology made by Japanese scientists.
Efforts have been made to expand the pressure range in KMA using harder anvil materials and optimizing pressure medium and gasket materials suitable for the hard anvils. Although pressure is essentially defined by the applied force divided by the compressed area, strength (or hardness) of anvil material mostly limits the possible pressure. Commercially available WC materials for anvils were very limited in late the 1970s and 1980s when KMA became popular in Japan and some other countries, and only very few laboratories, such as Okayama University, Nagoya University, and Australian National University, using adequate WC succeeded to produce pressures higher than 25 GPa, equivalent to the depths of the uppermost regions (i.e., about 700 km) of the Earth’s lower mantle. In reality, it was shown that the efficiency of pressure generation varied greatly at pressures above 15 GPa, depending on the hardness of WC anvils, and the greatest pressure in KMA using the available hardest WC was estimated to reach approximately 30 GPa.26)
Harder WC has been developed using ultrafine powders of WC and advanced sintering techniques particularly in the 2000s (Fujilloy TF05), which was successfully applied to generate pressures up to 41 GPa in KMA (T. Katsura, personal communications, 2005), although it should be noted that this anvil is rather fragile and cannot be used repeatedly in such an ultrahigh-pressure regime. Effort has also been made to create even harder WC for KMA in collaboration with some company engineers for ultrahard material production, resulting in much harder WC with extremely little binders (Fujilloy TJS01). Using this WC as the anvils for KMA, pressures up to 50 GPa were confirmed.27) Additionally, a combination of this novel WC and tapered cubes for the second-stage anvils of KMA resulted in pressures up to 65 GPa‡‡, which is the highest pressure reported in KMA utilizing WC anvils.28) Figure 5 compares the efficiency of pressure generation in KMA using various WC anvils of hardest grades (Toshiba F, Sumitomo BL130, Fujilloy TF05 and TJS01).
A performance test of high-pressure generation using commonly used WC anvils (F, BL130, TF05, and TJS01; see text) with an identical cell assembly and an anvil truncation of 1.5 mm.27) The outcomes utilizing SD (Sumitomo WD700) and NPD (synthesized at the GRC) anvils are also displayed for comparison. Note that the achievable maximum pressures using these anvils may be much higher than those shown here by further optimizing the cell assembly (see text and Fig. 6).
Pressure production using SD, which is much harder than WC, as the second-stage anvils for KMA was initially attempted utilizing synchrotron X-ray diffraction measurements at KEK. Pressures up to 41 GPa were confirmed at room temperature, using small SD cubes with an edge length of about 5 mm and anvil truncations of 0.5 and 1.0 mm.29) High temperature generation was also made using larger SD anvils with an edge length of roughly 10 mm and achieved temperatures to 2000 K30)–32) at pressures up to 30 GPa. Higher-pressure generation was not realized because the applicable press load was limited to 500 tons due to the limitations in the strength of the first-stage anvils to compress the second-stage anvils and also to the absence of an adequate LVP apparatus, which is necessary to evenly compress the Kawai cell with small SD anvils to higher press loads. Meanwhile, these initial investigations using SD anvils were made mostly by the researchers in Tohoku University, Nagoya University, the University of Tokyo, and Ehime University.
Larger SD anvils with an edge length of 14 mm were introduced as the second-stage anvils of KMA in late 1990s,33) and larger LVPs, such as a six-axis press17) and a modified DIA-type press (SPEED-mkII),34) were developed to safely compress the KMA cell to higher press loads of up to about 1000 tons, which is twice as high as those used for the smaller SD anvils of 10-mm edge length. The primary users of SPEED-mkII deployed at the beamline BL04B1 in SPring-8 for this purpose were those of Okayama University and Ehime University, and the achievable pressure in KMA rose yearly and recently surpassed 120 GPa‡‡ as a result of the competition between these two groups.35) Figure 6 chronologically shows reported maximum pressures using SD anvils using SPEED-mkII, while the changes in achievable pressures using WC and NPD anvils are also shown for comparison. It should be noted that the guide blocks of SPEED-mkII were replaced in 2010 by those of a new LVP installed at Geodynamics Research Center (GRC) (MADONNA-1500) with further better design for even compression of the second-stage anvils.
Chronological changes of the maximum pressures reported in KMA using SD anvils (open circles). The KMAs primarily utilized for the pressure evaluation at KEK and SPring-8 and the sizes of the SD anvil cubes used are indicated. The maximum pressures using WC (closed circles) and NPD (open squares) anvils are also shown for comparison. Guide blocks of SPEED-mkII were later replaced by those of MADONNA-1500 (MADONNA-GB) with better performance. It should be noted that the maximum pressures using various anvils shown here are generally higher than those shown in Fig. 5, as they are the results of optimization of the cell assemblages while the latter results are for a mutual comparison of the anvil performance using identical cell assemblages.
Synthesis of nano-polycrystalline diamond (NPD) was firstly reported by the authors using KMA, which was found to be much harder than SD and even harder than single crystal diamond.36) Highly transparent NPD with dimensions up to about 10 mm in both diameter and length can be synthesized utilizing a massive KMA built at the GRC, which was employed for many applications in high-pressure science and technology. Thus, synthesized NPD rods were cut into cubes with a 6.0-mm edge length and used as the second-stage anvils of KMA.
The greatest pressure of 88 GPa was recorded using the NPD anvils with an anvil truncation of 1.0 mm at a press load of 340 tons37) (Fig. 5). The pressure achieved by using SD anvils with the identical cell assembly was 55 GPa at the same press load, showing that the efficiency of pressure generation in KMA using NPD anvils is more than 50% higher than that using SD anvils. NPD cubes with an edge length of 7.0 mm can be created from available NPD rods, on which press load of up to about 460 tons would be applied. Moreover, optimization of pressure medium and gasket should result in further higher efficiency in pressure generation using NPD anvils, suggesting that pressures far higher than 100 GPa could be produced in KMA (Figs. 5 and 6).
NPD is highly transparent to visible light and X-ray beams, as compared to SD which includes small amounts of metal binders, such as Co and Ni. Thus, in situ optical and X-ray observations through NPD anvils can be made. Indeed, high quality X-ray imaging and diffraction were reported through the NPD anvils at high pressure.37) Furthermore, it is anticipated that in situ measurements of sample temperatures by optical spectroscopy via the NPD anvils are also possible. NPD should greatly contribute to new developments of KMA technology in the near future, as the “third-generation anvil material” after WC and SD.
In situ X-ray observations under high pressure using synchrotron facility significantly improved the quality of high-pressure experiments since the 1980s when the second-generation light sources, such as photon factory at KEK, became available in high-pressure sciences following some trials in applications of laboratory-based X-ray sources. For LVP experiments at KEK, a DIA-type cubic apparatus (MAX-80; also MAX-90 and MAX-III subsequently) was used because it could secure the X-ray path between the anvils, and the project was successfully made by the legendary “all Japan team”.38) In situ X-ray measurements in KMA were conducted using SD, which is more transparent to X-ray beams relative to WC, due to the limitations by the movement of the goniometer.29)–32) As SD anvils were very expensive, only very few groups afforded this kind of experiments at KEK.
A larger DIA-type apparatus with a 1500-ton press capacity (SPEED-1500; Fig. 7(a))39) for KMA was opened to the public in 1997 at the same time when the construction of the third-generation synchrotron facility (SPring-8) was completed in Japan. The author’s team of Ehime University led the initial stage of in situ observations using KMA with WC anvils at the related beamline (BL04B1) and succeeded in precise determination of the boundary between spinel and post-spinel phase transition in olivine.40) Since then, in situ X-ray measurements employing KMA became a widespread technique among deep Earth scientists and also materials scientists, which have been extensively used for determinations of phase relations, P-V-T equations of state, viscosities and structures of melts, etc., at pressures up to ∼30 GPa. Higher-pressure generation using SD and NPD anvils was also attempted using another KMA (SPEED-mkII) installed later at the same beamline,34) as stated above.
(Color online) Examples of LVP for KMA at synchrotron and neutron beamlines. (a) SPEED-1500 at SPring-8, (b) MAX-III at KEK, and (c) ATSUHIME at J-PARC (Rev. Sci. Instrum. 85, 113905).
Combinations of KMA and in situ X-ray observations with other physical property measurements led to new methods for determination of critical mineral physics parameters at high pressure and temperature. One of such techniques is for sound velocity measurement using ultrasonic interferometry, which provides sound velocities (Vp and Vs) for high-pressure minerals as a function of pressure and temperature. The initial technique for this measurement was created by researchers at Australian National University and Stony Brook University,41) which was transferred to SPring-8 with some modifications.42) Sound velocities of most major high-pressure phases in the deep mantle were determined at pressures corresponding to the uppermost lower mantle, which provided important constraints on the mineralogy of the deep mantle43) and subducted slabs.44)
Another significant example of advancements in KMA technology combined with synchrotron in situ X-ray observation is for deformation of minerals under high pressure and temperature. Such studies were first made by using deformation-DIA (D-DIA) apparatus,45) where the sample placed in a cubic pressure medium is deformed by the upper and lower anvils whose movements are precisely controlled by two hydraulic rams, independent on the main ram pressure. A larger version of D-DIA was built at PF-AR in KEK (MAX-III; Fig. 7(b)), and also the DIA-type guide blocks of SPEED-mkII were replaced with the MADONNA-type D-DIA guide blocks46) at SPring-8. Although the pressures available in these D-DIA apparatus have been limited to around 20 GPa, a new deformation KMA was invented, where two opposed second-stage anvils compress the sample in an octahedral pressure medium via a pair of anvils with a hexagonal prismatic shape. The motions of these two anvils in this KMA-based deformation apparatus are regulated by two separate rams. This apparatus with the “D111 guide blocks” (or “DT-Cup”) was originally developed in the U.S.A. and U.K.,47) followed by the implementation of its larger versions in Japan, including those at KEK and SPring-8. This type of modified KMA with the D111 guide blocks demonstrated the ability to perform deformation of minerals at pressures to 28 GPa48) and should provide crucial information on the rheological characteristics of high-pressure minerals under the lower mantle conditions.
In situ neutron observations at high pressure are important in deep Earth science, particularly for crystal structure refinements on hydrogen bearing systems, such as ice and hydrous minerals, as well as for identification of elements with close atomic numbers, which are difficult with X-ray observations. In contrast, since the intensities of neutron beams available at the current facilities are much weaker than those of synchrotron X-ray beams, higher sample sizes and longer exposure times are required in the neutron observations. Thus, only very limited high-pressure apparatus with opposed anvils, such as Paris-Edinburgh press,6) have been used for in situ neutron observations.
The LVP with six-axis press (ATSUHIME; Fig. 7(c))49) was built at the PLANET beamline of the spallation neutron source of Materials and Life Science Experimental Facility (MLF) of J-PARC. It was initially used as a cubic press to secure large sample volumes and paths for diffracted neutron beams. Attempts have also been made to employ ATSUHIME as KMA and recently succeeded to produce pressures to 23 GPa.50) It should be noted that conventional WC and SD with Co binders cannot be used as the anvils for the KMA cell, because Co absorbs neutron, leading to emission of the radioactive nuclei with long half-lives that are harmful to human bodies. Thus, newly created WC with Ni-bearing binder and SD with SiC binder are used for neutron observations employing ATSUHIME as KMA. ATSUHIME is the very first and the only KMA constructed at neutron facilities in the world, which should provide new insights into the materials in deep Earth and planetary interiors.
Very large LVPs for multianvil apparatus were previously built in Japan: one with a 15,000-ton hydraulic ram in Osaka University by Prof. Kawai as stated earlier and the other with a 10,000-ton ram in Nagoya University by Prof. Kumazawa. Both of these LVPs were originally designed to achieve pressures in Mbar regime, with different multi-anvil systems. However, these massive LVPs fell short of the objective at that time, and the highest pressure remained around 20 GPa‡.
The limitation in pressure generation was partly because adequate WC for the large second-stage anvils was unavailable at that time; significant plastic deformation hindered higher-pressure generation using traditional WC, while it was also difficult to make huge cubes of flawless WC using the sintering procedures, which might have caused anvil failure and led to frequent blowouts during compression. It was unfortunate that the large-volume KMA lost in the competition with DAC for higher-pressure generation; the latter showed its ability to generate pressures beyond 1 Mbar nearly simultaneously when these LVPs were built in the 1970s.7),25) Because WC anvils with large dimensions (i.e., those having edge lengths larger than 5 cm) were quite expensive and it was difficult to maintain these presses, both of these huge LVPs were dismantled by the end of the twentieth century, although some smaller presses with capacities of applying several hundred tons for KMA apparatus survived and spread in the world, as stated earlier.
The author attempted to revive the large-volume KMA press, not for higher-pressure generation but for use of its capacity to produce stable and homogeneous high temperature generation for novel materials synthesis under the ultrahigh-pressure regime46),51) (generally referred to the pressures greater than 10 GPa in materials sciences). The new KMA apparatus with press capacity of applying up to 6,000 tons, nicknamed as BOTCHAN-6000 (BOTCHAN, hereafter; Fig. 8), was constructed in 2009 at the GRC. The shapes and sizes of guide blocks, press frame, and first-stage anvils were newly designed so that uniform and even loads are applied on the second-stage anvils with the use of finite element analyses. The authors also tested a number of WC products to select those with the best performance in materials synthesis under the ultrahigh-pressure regime.51)
(Color online) Pictures of (a) BOTCHAN, (b) assembled second-stage WC anvils placed on the first-stage steel anvils, and (c) WC anvil cubes with various sizes; the most left anvils are for traditional KMA with an edge length of 26 mm, while those on the far right are the largest ones with 75-mm edge length for BOTCHAN (see text). Modified from Rev. High Press. Sci. Tech. 20, 158–165.
Figure 9 compares the sample volumes available in typical high-pressure apparatus as a function of pressure. Although DAC can produce pressures far higher than 300 GPa, the sample volume is generally limited to ∼10−4–10−6 mm3. The pressure in typical piston-cylinder-type apparatus is limited up to 3–5 GPa, depending on the strength of the WC used for piston-cylinder, although sample dimensions of a few cm are available using a massive uniaxial press. Belt (or girdle)-type apparatus and cubic anvil apparatus, which are frequently used for synthesis of diamond and cubic BN, can produce pressures up to ∼8 GPa in sample volumes of up to a few cm3.
Typical sample volumes in various LVPs as a function of pressure. The sample volumes of conventional KMAs using WC anvils are about 1 mm3, while those of about 1–2 cm3 are available in BOTCHAN at pressures of 15–20 GPa. Modified from Phys. Earth Planet. Inter. 228, 255–261.
The most popular KMA operated in a uniaxial press with a capacity of applying several hundred tons can produce pressures up to approximately 30 GPa using traditional WC anvils in typical sample volumes of a few mm3. By replacing the second-stage anvils of WC with harder SD anvils, pressures as high as 100 GPa can now be reached in KMA, but the sample volume is limited to significantly smaller than 1 mm3. In contrast, BOTCHAN generates 15 GPa for the sample volume of 1–2 cm3, while pressures up to 25 GPa can also be applied to the samples of ∼100 mm3. The authors use second-stage WC anvils with edge lengths of 52 mm, 65 mm, and 75 mm (cf. conventionally around 25–30 mm; Fig. 8), depending on the required sample sizes. Thus, BOTCHAN paved the way for “ultrahigh-pressure materials science”, where the sample size is crucial for applications of the synthesized materials.
One of the most successful materials synthesized under the ultrahigh-pressure regime using BOTCHAN is highly transparent and ultrahard NPD36) (Fig. 10(a)). NPD rods with dimensions up to approximately 1 cm in both diameter and length can be synthesized and have been successfully applied to high-pressure science and technology,52) including KMA with NPD anvils as previously mentioned, as well as for certain industrial applications.
(Color online) Some examples of (a) nano-polycrystalline diamond and (b) transparent nano-ceramics synthesized using a large-volume KMA.
Another example of the novel materials synthesized using large-volume KMA is transparent nano-ceramics (TNC), which are bulk samples made of high-pressure phases with grain sizes less than 100 nm. Such TNC are crystallized from glass starting materials, using fast nucleation above the glass transition temperature and slow atomic diffusion under the ultrahigh-pressure regime.53) Some of the TNC are as transparent as the corresponding single crystals and harder than the single crystals (Fig. 10(b)). Several TNC of high-pressure phases, including garnet, kyanite, jadeite, cubic BN, cubic Si3N4, etc., have been synthesized using KMA technology, and bulk rod samples of the TNC with dimensions of ∼1 cm can be synthesized using BOTCHAN, which are potentially significant for certain scientific and industrial applications.
The KMA technology has been developed mainly by Japanese scientists after its invention over 50 years ago by Prof. Kawai and his colleagues and recently reached pressures of the Mbar regime as originally targeted. A number of significant experimental studies mostly in geoscience have been made using updated KMA technology, combined with other methods such as in situ observations using quantum beams and physical property measurements, providing new insights into the structure, composition, dynamics, and evolution of the Earth’s deep interior.
On the other hand, stable and homogeneous temperature and pressure, in addition to the relatively large sample volumes, available in KMA are important for novel materials synthesis under very high pressure as proven by NPD, which is the very first material commercialized among those synthesized under the ultrahigh-pressure regime. In reality, following the successful applications of NPD employing BOTCHAN, several significant Japanese businesses built or intend to build large-volume KMAs for novel materials synthesis. Such trends are also seen in the U.S.A., where a large-volume KMA, which is basically identical to BOTCHAN and nicknamed as “ICHIBAN”, has just been constructed at a new organization (FORCE) in Arizona State University for the purpose of synthesis of novel functional materials, as well as for applications to deep Earth mineralogy.
In conclusion, KMA technology has been playing important roles not only in geoscience but also in materials science and related research fields, such as physics and chemistry, as a result of persistent efforts of scientists in the development of this technology in the past 50 years.
The author thanks Professor Yoshio Fukao for giving him the opportunity for writing this article, and Professor Masao Wakatsuki for providing him valuable information about the history of development of cubic presses. He also acknowledges Professors Tomoo Katsura, Takehiko Yagi, Eiji Ohtani, Eiji Ito, Akira Yoneda, Ken-ichi Funakoshi, Wataru Utsumi, R.C. Liebermann, and Yanbin Wang for discussion and collaboration in developments of KMA technology. Special thanks are due to Professor Yoshihisa Iio for a guided tour of Abuyama Observatory of Disaster Prevention Research Institute, Kyoto University.
Edited by Yoshio FUKAO, M.J.A.
Correspondence should be addressed to: T. Irifune, Geodynamics Research Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Ehime, Japan (e-mail: irifune@dpc.ehime-u.ac.jp).
This paper commemorates the 100th anniversary of this journal and introduces the following paper previously published in this journal. Kawai, N., Togaya, M. and Onodera, A. (1973) A new device for pressure vessels. Proc. Jpn. Acad. 49 (8), 623–626 (https://doi.org/10.2183/pjab1945.49.623).
‡ Pressure values above 10 GPa were somehow overestimated in the 1960s–1970s, because those based on the pressure reference points themselves were found overestimated.54) The precise pressures in these previous investigations are unknown but are unlikely far higher than 20 GPa, and here the author tentatively described the highest pressures in LVP as approximately 20 GPa during this time. Further reevaluation of the actual pressures reached in these earlier studies should be made based on the currently used pressure scales.
‡‡ The pressures at room temperature in KMA, where the sample is pressurized by hard pistons inside the octahedral pressure medium, are probably exaggerated because of the additional stress created by the pistons. The authors actually used a pair of NPD anvils inside the pressure medium and reported the maximum pressure of 125 GPa using the second-stage anvils of WC55) (and even achieved pressures exceeding 150 GPa at SPring-8 recently) but hesitate to claim this as the highest pressure recorded in KMA, as the pressure decreased down to ∼100 GPa with increasing temperature, partly due to the release of the stress. Similar pressure decreases are also found in these studies referenced in the text.
[From Proc. Jpn. Acad., Vol. 49 No. 8, pp. 623–626 (1973)]
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Tetsuo Irifune was born in Ise in 1954, graduated from Kyoto University, Faculty of Science, and obtained his PhD in 1984 from Hokkaido University. He worked at Australian National University (with Prof. A.E. Ringwood) as a postdoc and returned to Hokkaido University as an assistant professor in 1987. He moved to Faculty of Science of Ehime University in 1989 as an associate professor and was promoted as a professor in 1995. He established Geodynamics Research Center (GRC) of Ehime University in 2001, and since then he has been appointed as a professor and the director of GRC. He has also been appointed as the Distinguished Professor of Ehime University since 2012. He was selected as Fellows of American Geophysical Union and Japan Geoscience Union and received A.V. Humboldt Research Award (A.V. Humboldt Foundation), A.E. Ringwood Medal (Geological Society of Australia), R.W. Bunsen Medal (European Geoscience Union), P.W. Bridgman Medal (International Association for Advancement of High Pressure Science and Technology), and IMA medal (International Mineralogical Association), in addition to domestic awards/medals, including Medal with Purple Ribbon from the Japanese government.
