The observation of the growth and ifrured absorption for dust particles ecclosed in a small scale space

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The purpose of this study is to clarify the growth process of cosmic dusts in the interstellar space and to determine the optical property of the cosmic dusts in the laboratory. Our final goal of this experiment is that we observe the growth process of the dust particles in collision with time when various kinds of small dusts are enclosed in a small vacuum space for a long time. The chosen materials are ices, organic matters and silicates, and their sizes are from 0.1 to 1 mm. We also intend to analyze these dusts by using a infrared absorption method. In this term, we have finished to develop the instrument to enclose the dust particles, which is the most important part of this experiment, moreover we estimated the adhesion strength among the organic dust particles.We succeeded to enclose molecular ions for several hours by means of the developed instrument of dust enclosure, so called RF ion trap instrument in ultra-high vacuum chamber. This instrument has characteristics that there are 4 holes of the diameter of 5mm at the ion trap electrode necessary to observe the interior and that the electric gun is set as a lower electrode. We did a preliminary test with molecular ions, then we developed the impedance matching instrument for high frequency electric field in order to arrange the experimental conditions to enclose the dust particles. We improved our electrodes for the ion trap according to these preliminary tests.Before we try to enclose the organic dusts, we studied the adhesion force of ethylene glycol particles, which particles were formed by a spray, at 200 K.The adhesion force was measured by a flowing method. As a result, the adhesion force of the organic matter was concluded to be several orders of magnitudes larger than that of silicate particles.