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Fundamental Study on a High Brightness and High Resolution YAG Screen for Electron Microscopy

电子显微镜用高亮度高分辨率YAG屏幕的基础研究

基本信息

批准号：
07455036
负责人：
HIBINO Michio
金额：
$ 4.22万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455036/
关键词：
high voltage electron microscope TV-system high efficient scintillator YAG glass hemisphere lens coupling system 電子顕微鏡高効率シンチ-タ

项目摘要

Coupled by a lens optical system with a photo-cathode, a single crystal of YAG (Yttrium Aluminum Garnet) has been used for a scintillator, which exchanges electron images to light images, in a new TV system for an electron microscopy. Lens coupled YAG scintillator system has advantages for damages due to the high energy electron irradiation and for lowering contrast by the x-ray. It was difficult, however, to achieve both high brightness and high resolution with this system, because the high refractive index of YAG reflects most of the light emitted in the crystal at the YAG-vacuum interface. In order to over come this problem of total reflection, we have developed a new scintillator combined a platelet YAG crystal with a glass hemisphere and have designed newly lens optical system.[In the first year] ;1. New type YAG scientillators have been developed, a hemisphere YAG crystal for a 100 kV electron microscope and a combination of platelet YAG and a glass hemisphere for a 1000 kV electron microscope.2. A lens coupling optical system for the 1000 kV electron microscope has been designed.[In the second year] ;1 Combining the new YAG scintillator and the lens optical system with a SIT-type TV-tube, we have produced a new TV system for the high voltage electron microscope, and2. We evaluated its characteristics with a light source and the 1000 kV electron microscope as,(1) Resolution The resolution is 50-60 mum on YAG for 1000 kV electrons.The curvature of a image plane due to the hemisphere can be reduced with a proper focusing condition(2) Brightness The glass hemisphere improves the brightness by a factor of 3.(3) Distortion The distortion due to the hemisphere is -4% at the edge of the TV screen.(4) Diminishing in the surrounding area dose not affect more than 70% in the monitor, and it is improbable.(5) DQE 0.04-0.12Consequently, we demonstrated that the TV-system for HVEM which is resistant to an electron irradiation damage and the effect of x-ray is available.

在用于电子显微镜的新TV系统中，通过透镜光学系统与光电阴极耦合，YAG（钇铝石榴石）单晶已被用作闪烁体，其将电子图像转换为光图像。透镜耦合YAG闪烁体系统对于由于高能电子照射引起的损伤和对于由X射线引起的对比度降低具有优点。然而，用这种系统很难同时实现高亮度和高分辨率，因为YAG的高折射率反射了YAG-真空界面处晶体中发射的大部分光。为了克服这种全反射问题，我们研制了一种将片状YAG晶体与玻璃半球相结合的新型闪烁体，并设计了新的透镜光学系统。[In第一年;1。研制了新型YAG科研仪器，即半球形YAG晶体用于100 kV电子显微镜，片状YAG晶体与玻璃半球组合用于1000 kV电子显微镜.设计了1000 kV电子显微镜的透镜耦合光学系统。[In第二年] ; 1.将新型YAG闪烁体和透镜光学系统与SIT型电视管相结合，制成了一种新的高压电子显微镜电视系统。我们评价其特性与光源和1000千伏电子显微镜，（1）分辨率分辨率是50-60微米的YAG为1000千伏electrons. Curvature的图像平面，由于半球可以减少与适当的聚焦条件（2）亮度玻璃半球提高亮度的一个因素3。(3)失真在电视屏幕的边缘，半球造成的失真为-4%。(4)周围区域的衰减不会影响显示器中的70%以上，这是不可能的。(5)DQE 0.04- 0.12因此，我们证明了用于HVEM的TV系统是可用的，该TV系统抵抗电子辐照损伤和X射线效应。