Development of Field Emission Type Ultra-High Vacuum Gauge

场发射型超高真空计的研制

基本信息

批准号：
02555009
负责人：
NISHIKAWA Osamu
金额：
$ 6.85万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02555009/
关键词：
Tip Apex Field Emission Field Emission Microsocpe (FEM)Surface Ultra-High Vacuum Imaging Faraday Cage Vacuum Gauge

项目摘要

Field emission is the electron tunneling through the potential barrier lowered by the high electric field - 0.5V/A. The tunneling rate for the electrons confined in the surface varies sensitively with the adsorption of gas atoms and molecules. In this study the high field required for the field emission was realized by employing a hemispherical apex of a sharp tip of a field emission microscope (FIM) and by applying a high negative voltage. The vacuum was measured by observing the reduction rate of field emission current with time.The study aimed the following items : (1) Improvement of the existing vacuum system up to the vacuum of 10^<-11> - 10^<-13> Torr, (2) Clarification of the relation between the reduction rate of emission current and vacuum, (3) Examination of various metals as tip materials, (4) Evaluation of the advantageous point of multiple tips, (5) Development of a new highly efficient and reliable system to measure emission currents.The results of above items are as follows : (1) The vacuum better than 10^<-11> Torr could not be obtained possibly due to the insufficient surface refinish of the vacuum chamber, (2) It was found that the reduction rate of emission current is fairly well proportional to vacuum, (3) The study indicates that a W tip is more sensitive than an Ir tip for vacuum measurement because the W surface is more active than the Ir surface, (4) No multiple tip was examined because the study of item (5) must be preceded, (5) In order to measure the emission current efficiently and precisely, a 2-dimensional imaging Faraday cage was developed. Since the screen of the imaging cage projects the image of the currents emitted from every apex of the multiple tip, it allows us to examine all the tips directly at a single glance.

场发射是通过高电场降低的潜在屏障的电子隧道-0.5V/a。限制在表面中的电子的隧道速率随气体和分子的吸附而敏感。在这项研究中，通过采用半球形尖端的磁场发射显微镜（FIM）和施加高负电压，实现了场发射所需的高场。通过观察随时间的观察现场发射电流的降低来衡量真空。该研究的目的是以下项目：（1）改进现有的真空系统，直至10^<-11> -11> -10> -10^<-13> torr的真空，（2）澄清各种秘诀和真空材料的降低率，（4）澄清各种秘诀，（3）各种材料（3）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）开发一种新的高效和可靠的系统来测量排放电流。上述结果如下：（1）无法获得比10^<-11>托尔更好的真空，因此无法获得高于10^<-11>托尔的托尔，这可能是由于真空室的表面修补层不足所致（2）的提示是较大的提示，该提示比真空相当敏感的是（3），这是3）（3）iS（3）ww（3）ww iS（3）真空测量是因为W表面比IR表面更活跃，（4）由于必须在项目（5）的研究之前进行多个尖端，因此（5）为了有效地测量发射电流，开发了二维成像法拉第笼子。由于成像笼的屏幕投影了从多个尖端的每个顶点发出的电流的图像，因此它使我们能够直接检查所有尖端。