| Co-Investigator(Kenkyū-buntansha) |
KUROSAWA Masanori Univ.of Tsukuba, Inst.of Geoscience, Assistant, 地球科学系, 助手 (50272141)
KURITA Kei Tokyo Univ., Inst.of Earth & Planetary Physics, Assoc.Professor, 地球惑星物理学, 助教授 (00111451)
中井 泉 東京理科大学, 理学部・応用化学, 助教授 (90155648)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1995: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1994: ¥6,600,000 (Direct Cost: ¥6,600,000)
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| Research Abstract |
This study was carried out using a newly designed "Temperature adjustable specimen irradiation chamber" installed on a beam line in the UTTAC (University of Tsukuba Tandem Accelerator Center). For the irradiation specimen, simple carbon materials such as graphite, coal, and synthetic and natural diamonds were firstly employed instead of interstellar dust like carbon materials such as PAH because of their simple structures. The specimens on a ladder like specimen holder were irradiated by proton beams of different energies and currents. During the experiments, luminescence was observed on the diamond specimens. We investigated this ion-luminescence of diamond caused by the proton beam bombardment as the part of this study, because there are very few reports on the ion-luminescence phenomena, and the luminescence is a very sensitive probe on the detection of the formation and alteration of the structural defect in crystal. The ion-luminescence spectra were taken at near the liquid nitrog
… More
en temperature and were compared with those of cathode luminescence spectra. The spectra were almost similar to those of cathode luminescence at the beginning, but several new peaks were observed at the late stage of the irradiation. The combination analysis of PIXE and the ion-luminescence will be an effective method for analyzing the species and the structures of impurities in the defect.
The irradiated specimens were investigated by the optical methods such as FTIR,Raman spectrometry, ESCA,etc. As the results, although the break down of graphite structure to amorphous carbon, and the alteration growth from amorphous to graphite were observed, transformation to the diamond structure from other phases was not detected in this investigation. However, all the diamonds in meteorites and the diamond found in coal with high U content, which may be related with irradiation of cosmic-ray or radiation of U,are in Angstrom size, and it is conceivable that this transformation can be stabilized only in the Angstrom size. If diamond is Angstrom size, optical methods used in this study are not able to detect such a small size phases. We are now carrying out evacuation experiment of the graphite and amorphous phases in the irradiated carbon specimens using chlorine peroxide for concentrating the possible diamond phase occurred by the irradiation experiments. The residues of this evacuation experiments are observed by TEM and SEM.This observation is now on the way. We will continue this study and extend the specimen to other carbon materials such as PAH. Less
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