Japan Geoscience Union Meeting 2014

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International Session (Oral)

Symbol S (Solid Earth Sciences) » S-IT Science of the Earth's Interior & Techtonophysics

[S-IT03_29AM1] Structure and dynamics of Earth and Planetary deep interiors

Tue. Apr 29, 2014 9:00 AM - 10:45 AM 418 (4F)

Convener:*Satoru Tanaka(Institute for Research on Earth Evolution Japan Agency for Marine-Earth Science and Technology), Takashi Yoshino(Institute for Study of the Earth's Interior, Okayama University), Masanori Kameyama(Geodynamics Research Center, Ehime University), Dapeng Zhao(Department of Geophysics, Tohoku University), John Hernlund(ELSI, Tokyo TECH), Chair:Dapeng Zhao(Department of Geophysics, Tohoku University), Takashi Yoshino(Institute for Study of the Earth's Interior, Okayama University)

10:30 AM - 10:45 AM

[SIT03-07] Semiconductor diamond heater (SCD): An innovation for ultrahigh temperature experiments in the Kawai cell

*Longjian XIE1, Eiji ITO1, Akira YONENDA1 (1.Institute for Study of the Earth Interior , Okayama University)

Keywords:Semiconductor Diamond Heater, Ultrahigh Temperature, Kawai Cell

We developed the semi-conductor diamond heater in the Kawai high pressure cell. The starting material of the semi-conductor diamond heater is born(B)-doped burned-graphite. We succeeded to improve the machinability of the B-doped burned-graphite by decreasing porosity. Following is the motivation and the background of the semi-conductor diamond heater project. It is important to generate extremely high temperature (~3000 ℃) in a large sample volume (~0.1mm3) in the Kawai apparatus.X-ray transparency is also desirable for in-situ synchrotron analysis. However, any traditional heater used in the Kawai apparatus so far does not satisfy the both requirements simultaneously. Semiconductor diamond is a candidate material to generate temperatures higher than 3000℃ with low x-ray absorption. Anton Shatskiy (2009) have generated a temperature of 3500℃ by using the semiconductor diamond heater in a large-volume Kawai-type high-pressure apparatus, although their temperature measurement is questionable from a viewpoint of the power-temperature relation. Furthermore, their semi-conducted diamond heater, made of boron and graphite powders, was not machinable and difficult to control the temperatures. It often became unstable at around 1000~1300℃and impossible to generate higher temperature.Systematic experiments have done to improve the performance of the semiconductor heater. We used a machinable block of graphite contain 3 wt.% boron as the starting material for the semi-conductor diamond heater. The graphite-diamond transformation started at ~1000-1200℃ at 15 GPa in the Kawai apparatus. After the transformation, we stably generated temperature to 2000 ℃. Activation energy of B-doped diamond is about 0.1 eV, which is much lower than that of pure diamond (5.45eV).References:Anton Shatskiy, Daisuke Yamazaki, Guillaume Morard, Titus Cooray, Takuya Matsuzaki et al. , Review of Scientific Instruments 80, 023907 (2009).