Abstract：The metastable krypton atoms have high internal energy, and they will be de-excited to produce electrons when they collide with the metal surface. The electron lens is used to image and detect the de-excited electrons to realize the characterization of the intensity and spatial distribution of the metastable krypton atom beam. Based on this principle, a metastable krypton atom beam imaging system is designed, and the finite element analysis method is used to study the influence of electrode spacing, thickness and electric potential on the movement of the de-excited electron beam. The results show that the imaging dispersion decreases with the improvement of the focusing ability of the electronic lens. The imaging error of each object point of the metastable krypton beam is below 2mm, the imaging size is 16.5mm, the average error is 3.71%, and the maximum error is 9.38%.
［1］Ahlswede J, Hebel S, Ross J O, et al. Update and improvement of the global Krypton-85 emission inventory［J］. Journal of Environmental Radioactivity, 2013, 115(1): 34-42.
［2］Lu Z T, Schlosser P, Smethie W M, et al. Tracer applications of noble gas radionuclides in the geosciences［J］. Earth-Science Reviews, 2014, 138(1): 196-214.
［3］Verniani F. The total mass of the Earths atmosphere［J］. Journal of Geophysical Research, 1966, 71(2): 385-391.
［4］Winger K, Feichter J, Kalinowski M B, et al. A new compilation of the atmospheric 85krypton inventories from 1945 to 2000 and its evaluation in a global transport model［J］. Journal of Environmental Radioactivity, 2005, 80(2): 183-215.
［5］Chen C Y, Li M Y, Balley K, et al. Ultrasensitive Isotope Trace Analyses with a Magneto-Optical Trap［J］. Science, 1999, 286(5442): 1139-1141.
［6］Du X, Purtschert R, Bailey K, et al. A New Method of Measuring 81Kr and 85Kr Abundances in Environmental Samples［J］. Geophysical Research Letters, 2003, 30(20): 2068.
［7］Wei J, Hu S M, Lu Z T, et al. Latest development of radiokrypton dating-A tool to find and study paleogroundwater［J］. ScienceDirect Quaternary International, 2020, 547(1): 166-171.
［8］Panock R L, Freeman R R, White J C, et al. Multiphoton excitation and subsequent ionization detection of metastable atoms: measurement of n3S-n3D splittings in He［J］. Optics letters, 1980, 5(4): 160-2.
［9］Borovik A A, Rojas H L , King G C. A surface detector for metastable atoms［J］. Measurement ence & Technology, 2000, 11(3): 42-45.
［10］Schneble D, Hasuo M, Anker T, et al. Detection of cold metastable atoms at a surface［J］. Review of Science Instruments, 2003, 74(5): 2685-2689.
［11］Miura N, Hopwood J. Metastable helium density probe for remote plasmas［J］. The Review of scientific instruments, 2009, 80(11): 113502.
［12］Jiang W, Bailey K, Lu, Z T, et al. Ion current as a precise measure of the loading rate of a magneto-optical trap.［J］. Optics letters, 2014, 39(2): 409-12.
［13］胡树国, 张体强. 高纯氦气中杂质标准物质的研制［J］. 计量学报,2018,39(6): 908-913.
Hu S G, Zhang T Q. Development of Impurity Reference Materials in High Purity Helium［J］. Acta Metrologica Sinica, 2018, 39(6): 908-913.
［14］刘祖平, 冯光耀. 束流光学［M］. 合肥: 中国科学技术大学出版社, 2014.
［15］时仪. 基于COMSOL的四极质谱仪仿真研究与结构优化［D］. 合肥: 合肥工业大学, 2018.
［16］张立峰, 朱炎峰. 电容层析成像系统阵列电极三维优化设计［J］. 计量学报, 2020, 41(8): 947-952.
Zhang L F, Zhu Y F. Three-dimensional Optimal Design of Array Electrode for Electrical Capacitance Tomography System［J］. Acta Metrologica Sinica, 2020, 41(8): 947-952.
［17］马敏, 孙颖, 范广永. 基于深度信念网络的ECT图像重建算法［J］. 计量学报, 2021, 42(4): 476-482.
Ma M, Sun Y, Fan G Y. ECT Image Reconstruction Algorithm Based on Depth Belief Network［J］. Acta Metrologica Sinica, 2021, 42(4): 476-482.
［18］柏占伟, 谢志江, 袁晓东, 等. 影响激光驱动器注入镜组特性的误差因素分析［J］. 计量学报, 2014, 35(6): 559-564
Bai Z W, Xie Z J, Yuan X D, et al. AnaIysis of Error Factor Impacting on the Performance of Laser-driver Injection Compound Lens［J］. Acta Metrologica Sinica, 2014, 35(6): 559-564.
2022, Vol. 43 
