Study on mutual interaction between high energy ion beams and carbon materials related to interstellar material

这项研究是使用在筑波大学串列加速器中心(UTTAC)的束流线上安装的新设计的“可调温样品照射室”进行的。对于辐照样品，由于结构简单，首次使用了简单的碳材料，如石墨、煤和人造和天然钻石，而不是星际尘埃状的碳材料，如PAH。梯形样品架上的样品被不同能量和电流的质子束照射。在实验过程中，观察到了金刚石样品的发光。由于离子发光现象的报道很少，而且这种发光是探测晶体中结构缺陷的形成和变化的一个非常灵敏的探针，所以我们把这种由质子束轰击引起的金刚石的离子发光作为研究的一部分。离子发光光谱是在液氮…附近拍摄的较高的En温度，并与阴极发光光谱进行了比较。结果表明，辐照初期的光谱与阴极发光基本一致，但在辐照后期观察到了几个新的发光峰。PIXE和离子发光的结合分析将是分析缺陷中杂质的种类和结构的有效方法。用FTIR、拉曼光谱、ESCA等光学方法对辐照后的样品进行了研究。结果表明，虽然观察到石墨结构分解为无定形碳，并从非晶态向石墨转变，但没有检测到其他相向金刚石结构的转变。然而，陨石中的所有钻石和高铀煤中发现的钻石，可能与宇宙线的照射或铀的辐射有关，都是埃级的，可以想见，这种转变只有在埃级才能稳定下来。如果钻石是埃斯特罗姆大小的，本研究中使用的光学方法无法检测到如此小的相。为了浓缩辐照实验中可能出现的金刚石相，我们正在用过氧化氯对辐照后的炭样中的石墨相和无定形相进行抽空实验。用透射电子显微镜和扫描电子显微镜观察了疏散实验的残留物，现在正在进行观察。我们将继续这项研究，并将样本扩展到其他碳材料，如多环芳烃。较少

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