Construction of a very low temperature specimen stage for the 400kV Analytical Atom Resolution Eletron Microscope.

本研究旨在构建适用于400KV分析原子分辨电子显微镜(AARM)的超低温样品台。精心设计了低温阶段，使400KVAARM的各项性能得以保留。为此，大阪大学的400KVAARM和JEOL株式会社的400KVAARM都被用来测试目前的极低温样品台的性能。为了检测特征X射线分析材料和二次电子来查看扫描电子显微镜图像，目前的低温试件台具有侧入式测角仪的形式。然而，这种测角仪对机械振动的影响很弱，很难获得高分辨率的图像。虽然消除震动并不是不可能的，但由于资金有限，它的目标是并成功的…由于电子显微镜必须具有0.2-0.3 nm的分辨率才能直接看到原子的图像，因此另一种适用于超导电子透镜(SCEL)样品台的高分辨率和极低温度(液氦温度)的样品夹持器是值得参考的。虽然该样品台可以在液氦温度下揭示样品的原子结构，但无法探测到特征X射线，也不能进行温度变化。然而，可以使用在显微镜底部制造的电子能量损失光谱仪进行元素分析。利用AARM的侧入极低温样品台和SCEL中的低温台，对超导材料Lt；Nb_3&Gt；Sn在室温到30K的不同温度下的像、5K下Th-热分解的原子分辨图像和5K下电子辐照下Th-热分解的变化进行了观测。通过本研究可知，低温试件台的性能可以得到改善。经过改进，目前低温试件台的温度降到了20K，但试件位置的机械振动却达到了20 nm。目前正在向冈山理工大学和文部省申请在冈山理工大学安装400kVAARM，并计划与低温课题组一起开展原子尺度的广泛低温研究。较少

The present research aimed to construct the very low temperature specimen stage adaptable to 400kV Analytical Atom Resolution Electron Microscope (AARM). The low temperature stage has been made by paying the careful attention which enable every performance of the 400kV AARM to be preserved. For this aim, Both the 400kV AARM in Osaka University and in JEOL Ltd. has been used for testing the capabilities of the present very low temperature specimen stage.Specimens can be tilted in both X and Y axes with +10 , which is useful to study the crystalline specimens. In order to detect the characteristic X-ray to analyze the materials and secondary electrons to see the SEM images, the present low temperature specimen stage has the side entry goniometer style. However,this style of the goniometer is very weak for mechanical vibration and rather difficult to obtain high resolution images. Though elimination of the vibration is not impossible, since the fund is limited, it was aimed and succeeded … More that the resolution is 2.5 nm and the lowest temperature of a specimen is 30 K.Since it is clear that the electron microscope must have the resolution of 0.2 -0.3 nm in order to see the images of atoms directly, another specimen holder with high resolution and very low temperature ( the temperature of the liquid helium ) adaptable to the specimen stage in the superconducting electron lens (SCEL) has been made for reference. Though this specimen stage can reveal the atomic structure of the specimen in liquid helium temperature, the characteristic X-ray cannot be detected and also no temperature variation can be carried out. However element analysis can be carried out using the electron energy loss spectrometer fabricated at the bottom of the microscope. Movement of atoms and their clusters can also be observed by TV-camera and recorded in video tape recorder (VTR).Using the side entry very low temperature specimen stage to the AARM together with the low temperature stage in the SCEL, some observations of images of a superconducting material <Nb_3> Sn at various temperatures from room temperature to 30 K, atom resolution images of Th-pyromeritate at 5 K and the variation of Th-pyromeritate by electron irradiation at 5 K have been carried out. Some variation of the images were recorded in VTR.After the present research, it was known that the performance of the low temperature specimen stage can be improved. After some improvements, the temperature of the present low temperature specimen stage was lowered to be 20 K but the mechanical vibration becomes as large as 20 nm in the specimen position. The origin of the vibration is now under studying, but the results obtained so far are reported.The present investigations are now applying to the Okayama University of Science and the Ministry of Education , science and Culture to install 400 kV AARM in Okayama University of Science and planning to carry out the extensive low temperature research in atomic scale together with low temperature research group. Less