TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 65 (No. 3), pp. 199-202, 2013

Magnetic ejection of diamagnetic sub-millimeter grains observed by a chamber-type μG generator orientated to identify material of a single particle

K. Hisayoshi1,2, C. Uyeda1, K. Kuwada1, M. Mamiya3, and H. Nagai3

1Institute of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
2Kasugaoka High-school of Osaka prefecture, Ibaraki, Osaka 563-0031, Japan
3National Institute of Advanced Technology (AIST), Tsukuba Central, Tsukuba, Ibaragi 305-8565, Japan

(Received November 7, 2011; Revised July 26, 2012; Accepted August 23, 2012; Online published March 12, 2013)

Abstract: A principle to identify the material of a single particle without destroying the sample is examined by an experiment in microgravity (μG). Such an identification is important as a first stage of analyzing various grains of primitive materials. The identification was based on diamagnetic susceptibility χDIA obtained from translation of the grain induced by a magnetic field. When a grain is released in an area of a monotonously decreasing field under μG conditions, it will be ejected in the direction of the field reduction; here, the area is occupied with diffused gas medium. The material identification of a primitive grain is possible by comparing the measured χDIA with published values; an intrinsic χDIA value is assigned to a material according to a molecular orbital model. We report here that the ejection is realized for sub-mm-sized crystals of various organic and inorganic materials. By developing a short drop shaft (μG duration ∼0.5 s), the proposed material identification can be easily performed in an ordinary chamber. Using conventional methods, χDIA cannot be detected for a small sample of diameter below the level of a millimetre. The achieved result is a step to realize the identification of micron-sized grains that compose primitive materials.
Key words: Magnetic ejection, chamber-type drop shaft, graphite, bismuth, polyethylene.

Corresponding author E-mail: hisayoshi@ess.sci.osaka-u.ac.jp

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