强流静电会聚LaB_6阴极电子枪研究
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摘要
强流电子枪在超高频器件、电子束焊接、材料表面改性和电子束机械加工等方面有广泛的用途。如在电子束表面改性方面,通过对比未辐射和辐射试样的断面EPMA(电子探针)和SEM(扫描电子显微镜)图像,可以看出显微组织明显改善,相应地引起机械性能的提高,同时操作简单,而且不会破坏零件的结构。因此,研究性能可靠的电子枪具有十分重要的意义。
要获得性能可靠的电子枪,阴极材料的选择非常关键,因为这关系到器件的寿命和稳定性。实验表明:六硼化镧(LaB6)具有高导电率和良好的热稳定性、化学稳定性、低功函数以及活性阴极表面,因此从理论上成为了阴极材料的理想选择。
传统的强流电子枪几乎都采用了电、磁混合聚焦的方式,磁聚焦尽管技术十分成熟,但因为涉及到高、低压的绝缘问题,结构十分复杂,很难用在对重量要求很苛刻的条件下,如空间焊接。而采用纯静电方式会聚的电子枪降低了器件的复杂程度,减轻了器件的重量,因此具有独特的优势。
电子枪设计的基本方法有理论设计、实验和图解等方法,但因为理论设计要求很高,需要繁琐的公式推导,结构也不能太复杂,而得到的结构多是复杂曲面,给加工又带来很大的困难。实验法和图解法因为精度不高,现在已经很少使用。随着电子计算机技术和计算技术的发展,现在流行的设计方法是根据设计要求,首先设计出初始模型,然后通过计算软件的模拟,根据模拟的结果再修正模型,如此反复,直到得出满意的结果。这种方法节约了成本和时间,减少了实验的次数和盲目性,提高了设计的效率,增加了设计的准确性。
本文旨在研究探索强流静电会聚六硼化镧阴极电子枪各个参数对其性能的影响,设计出性能优良的电子枪系统。首先根据设计的要求(在5000V的总电压下,输出300mA的强流电子束)设计出初始的计算模型,再编写MAGIC代码对初始模型进行计算机仿真,根据模拟的结果,再修正模型的结构或者参数,得出满意的结果后再进行详细的结构设计。在实验室现有的条件下,因为仅有2500V电源,为验证设计的准确性,在修改了一定的结构和参数后,在2000V总电压下进行实验验证模拟仿真的结果。通过实验发现,实验结果和模拟结果基本吻合,因此可以认为,在5000V总电压下输出300mA的设计是可行的。
High current electron guns are widely used in high frequent devices, electron beam jointing, surface modification of materials and mechanical manufacture etc. Taking surface modification of materials for example, cross-sectional EPMA (Electron Probe Micro-Analyzer) and SEM (Scanning Electron Microscope) images of the untreated and irradiated samples give a direct observation on microstructures, suggest a corresponding improvement in mechanical properties. at the same time, it easy to operate, avoid to destroy the partings. So it is meaningful to study the e-guns with robust properties.
In order to obtain reliable e-guns, it is very important to select materials of cathode, for it determine the life and stability of the guns. The previous experiments testify that the LaB6 has the properties of high conductivity, well stabilities of thermal and chemical, low work function and active cathode surface etc. So it is a perfect choice of cathodal materials.
Traditional high current electron beam is always focused by the magnetic or electronic and magnetic hybrid method. Although the magnetic focusing technique is so mature, the problem that can not avoid is the insulation of high voltage and low voltage. So the structures are very complicated and can not satisfy the requirements the situation that has weight limitation, such as space weld. But the problem can be solved by pure electrostatic field focused e-guns.
The classical ways to design an electron gun include theory design method, schematic method and experimental method. But the theory design method need fussy formula evolvement, the structure must be very simple, and the results are always complicated curves, so it’s difficult to produce. The schematic and the experiment methods can not be satisfied the requirements for their high tolerance, so seldom to use now. As the development of computer technology and numerical technology, the popular way to design guns is to propose a prototype according to the requirements, and to simulate the model by computer, then, modify the model if necessary by the results of simulation, simulate again, until yield the reasonable results. This method saved the cost and time, reduce the blindness of experiments, improved the efficiency and precision of design.
The main objective of this paper is to study that the different parameters how to effect the performance of high current electron guns focused by the pure electrostatic field with LaB6 cathode, and to make the e-guns with good performance. Firstly, design the prototype according to the demand, to yield 300mA current at the total voltage of 5000V, next to simulate the model by MAGIC software, and modify the model according to the results, and then simulate again. Mechanical design goes after getting the reasonable results. For the limitation of the power, there is only a direct power with 2500V. So modify the structure and some parameters to test at the total voltage 2000V. The tests indicate its coherence with the simulation. So the results of simulation at the total voltage of 5000V can be used in the detail structure design.
要获得性能可靠的电子枪,阴极材料的选择非常关键,因为这关系到器件的寿命和稳定性。实验表明:六硼化镧(LaB6)具有高导电率和良好的热稳定性、化学稳定性、低功函数以及活性阴极表面,因此从理论上成为了阴极材料的理想选择。
传统的强流电子枪几乎都采用了电、磁混合聚焦的方式,磁聚焦尽管技术十分成熟,但因为涉及到高、低压的绝缘问题,结构十分复杂,很难用在对重量要求很苛刻的条件下,如空间焊接。而采用纯静电方式会聚的电子枪降低了器件的复杂程度,减轻了器件的重量,因此具有独特的优势。
电子枪设计的基本方法有理论设计、实验和图解等方法,但因为理论设计要求很高,需要繁琐的公式推导,结构也不能太复杂,而得到的结构多是复杂曲面,给加工又带来很大的困难。实验法和图解法因为精度不高,现在已经很少使用。随着电子计算机技术和计算技术的发展,现在流行的设计方法是根据设计要求,首先设计出初始模型,然后通过计算软件的模拟,根据模拟的结果再修正模型,如此反复,直到得出满意的结果。这种方法节约了成本和时间,减少了实验的次数和盲目性,提高了设计的效率,增加了设计的准确性。
本文旨在研究探索强流静电会聚六硼化镧阴极电子枪各个参数对其性能的影响,设计出性能优良的电子枪系统。首先根据设计的要求(在5000V的总电压下,输出300mA的强流电子束)设计出初始的计算模型,再编写MAGIC代码对初始模型进行计算机仿真,根据模拟的结果,再修正模型的结构或者参数,得出满意的结果后再进行详细的结构设计。在实验室现有的条件下,因为仅有2500V电源,为验证设计的准确性,在修改了一定的结构和参数后,在2000V总电压下进行实验验证模拟仿真的结果。通过实验发现,实验结果和模拟结果基本吻合,因此可以认为,在5000V总电压下输出300mA的设计是可行的。
High current electron guns are widely used in high frequent devices, electron beam jointing, surface modification of materials and mechanical manufacture etc. Taking surface modification of materials for example, cross-sectional EPMA (Electron Probe Micro-Analyzer) and SEM (Scanning Electron Microscope) images of the untreated and irradiated samples give a direct observation on microstructures, suggest a corresponding improvement in mechanical properties. at the same time, it easy to operate, avoid to destroy the partings. So it is meaningful to study the e-guns with robust properties.
In order to obtain reliable e-guns, it is very important to select materials of cathode, for it determine the life and stability of the guns. The previous experiments testify that the LaB6 has the properties of high conductivity, well stabilities of thermal and chemical, low work function and active cathode surface etc. So it is a perfect choice of cathodal materials.
Traditional high current electron beam is always focused by the magnetic or electronic and magnetic hybrid method. Although the magnetic focusing technique is so mature, the problem that can not avoid is the insulation of high voltage and low voltage. So the structures are very complicated and can not satisfy the requirements the situation that has weight limitation, such as space weld. But the problem can be solved by pure electrostatic field focused e-guns.
The classical ways to design an electron gun include theory design method, schematic method and experimental method. But the theory design method need fussy formula evolvement, the structure must be very simple, and the results are always complicated curves, so it’s difficult to produce. The schematic and the experiment methods can not be satisfied the requirements for their high tolerance, so seldom to use now. As the development of computer technology and numerical technology, the popular way to design guns is to propose a prototype according to the requirements, and to simulate the model by computer, then, modify the model if necessary by the results of simulation, simulate again, until yield the reasonable results. This method saved the cost and time, reduce the blindness of experiments, improved the efficiency and precision of design.
The main objective of this paper is to study that the different parameters how to effect the performance of high current electron guns focused by the pure electrostatic field with LaB6 cathode, and to make the e-guns with good performance. Firstly, design the prototype according to the demand, to yield 300mA current at the total voltage of 5000V, next to simulate the model by MAGIC software, and modify the model according to the results, and then simulate again. Mechanical design goes after getting the reasonable results. For the limitation of the power, there is only a direct power with 2500V. So modify the structure and some parameters to test at the total voltage 2000V. The tests indicate its coherence with the simulation. So the results of simulation at the total voltage of 5000V can be used in the detail structure design.
引文
[1]杜秉初,汪健如.电子光学.北京:清华大学出版社,2002
[2]赵国骏,于毓麟,阮宝崧等.电子光学.北京:国防工业出版社,1980
[3]赵健闯,安健.强流脉冲电子束表面改性Al-Si-Pb合金摩擦学性能及数值模拟:硕士学位论文,吉林:吉林大学,2003
[4]王德,李春旭.空间电子束焊枪电子光学系统的设计:硕士学位论文,兰州:兰州理工大学,2004
[5]王汉斌,许州,黎明等.单晶LaB6阴极直流发射特性实验研究和强流电子枪及加速管物理研究:硕士学位论文,北京:中国工程物理研究院,2005
[6]廖平,杨海中.行波管电子光学系统CAD技术研究:博士学位论文,成都:电子科技大学,2003
[7] Robert J. Barker Edl Schamiloglu.高功率微波源与技术,北京:清华大学出版社2005
[8]成建波,冉启钧.六硼化镧阴极,成都:成都电讯工程学院出版社,1988
[9]翟兴林等.高亮度注入器电子枪研制,强激光与离子束,1994,6(3): 419-422
[10] H.Ahmed, A.N.Broers. Lanthanum Hexaboride Electon Emitter, Appl Phys,1972,43(5): 2185- 2192
[11] K.N.Leung, P.A.Pincosy, K.W.Ehlers. Directly Heated Lanthanum Hexaboride Filaments. Rev Sci Instrum, 1984,55(7):1064-1068
[12] Longo R. A Study of Thermal Emitters in the Regime of Practical Operation[A]. Proc Int Electron Devices Meet.1980:467-470.
[13]光电信息学院.阴极电子学讲义.2004
[14] MARC E, HERNITER, WARD D, et al. High Current Density Results From a LaB6 Thermionic Cathode Electron Gun,IEEE TRANSACTIONS ON PLASMA SCIENCE.VOL 18.NO.6.DECEMBER 1990
[15] MARC E, HERNITER, WARD D, et al. Thermionic Cathode Electron Gun for High Current Density, IEEE TRANSACTIONS ON PLASMA SCIENCE. VOL PS-15. NO. 4. AUGUST 1987
[16]盛新庆.计算电磁学要论.北京:科学出版社,2005
[17] S. Michizono, H.Tsutsui, S. Matsumoto, et al. ELECTRON GUN SIMULATION USING MAGIC: Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 Japan
[18] http://www.mrcwdc.com/Magic/toolsuite.html
[19] B.Goplen, L.Ludeking, David Smithe, et al. User-configurable MAGIC for electromagnetic PIC calculations. ELSEVIER: Computer Physics Communications 87 (1995) 54-86
[20]奎克,赛尔达著,韩郑生译.半导体制造技术.电子工业出版社.2004
[21] W.B.Herrmannsfeldt. NUMERICAL DESIGN OF ELECTRON GUNS AND SPACE CHARGE LIMITED TRANSPORT SYSTEMS. SLAC-PUB-2631 October 1980
[22]罗德均,祁康成,林祖伦,等.强流静电会聚电子枪系统计算机模拟研究,电子器件(已录用,近期发表)
[23] http//www.sd-wit.com/amd/LaB6.htm 2004
[24] D.M.Goebel, Y.Hirooka, T.A.Sketchley. Large-area Lanthanum Hexaboride Electon Emitter. Rev Sci Instrum,1985,56(9):1717-1722
[25]童林夙,西门纪业,电子光学系统计算机辅助设计,北京:国防工业出版社,1990
[26]王小菊,林祖伦.场发射阴极的计算机模拟:硕士学位论文,成都:电子科技大学,2003
[27]孙伯尧等.电子离子光学计算机辅助设计,北京:清华大学出版社,1991
[28]承欢,江剑平.阴极电子学,北京:电子工业出版社,1983
[29]刘盛纲,微波电子学导论,北京:国防工业出版社,1985
[30]《电子工业生产技术手册》编委会,电子工业生产技术手册(四)电真空器件卷,1991,648-649
[31] A.Yutani, A.Kobayashi, A.Kinbara. Work functions of thin LaB6 films.Applied Surface Science 70/71(1993)737-741
[32]廖复疆.真空电子技术.北京:国防工业出版社,2001
[33] M.A.KhakooJr, S.K.Srivastava. A compact high current pulsed electron gun with subnanosecond electron pulse widths. J. Phys. E: Sci. Instrum., Vol. 17, 1984
[34] J. J. Watrousa, J. W. Lugisland , G. E. Sasser. An improved space-charge-limited emission algorithm for use in particle-in-cell codes. PHYSICS OF PLASMAS Vol 8, 2001
[35]黄运添,郑德修.电子材料与工艺学.西安交通大学出版社.1990
[37] http://www.china-machine.comladv technologylkey_teclkey_item49.htm 2005
[38]何成旦等.电子枪新型阴极的设计.甘肃工业大学学报,2003, 29(3):1-5.
[39]电子管设计手册编委会.行波管电子光学系统设计手册.北京:国防工业出版社,1981
[40]电子管设计手册编委会.微波电子管磁路设计手册.北京:国防工业出版社,1984
[41] Dionne N.J,et al. Three-Dimensional Simulation of Gridded TWT Guns, Tech.Dig.Int.Eletron
[42] Devices Meeting, Washinton,D.C.,1980:479-482[26] Mankofsky A.. Linear accelerator and beam optics codes. A.I.P. Conf. Proc. No.177. New York,NY, 1988
[43] Petillo J, Eppley K, Panagos D, et al. The MICHELLE Three-Dimensional Electron Gun andCollector Modeling Tool:Theory and Design. IEEE Trans on PS,2002,30(3):1238-1264
[44] Petillo J, et al. 3-D Particle-in-cell Simulations for Multi-stage Depressed Collector Design,Proc 1988 Microwave Power Tube Conf., Monterey, CA,1988,2C-5
[45] Coco S, Emma F, Laudani A, et al. COCA: A Novel 3-D FE Simulator for the Design of TWTs Multistage Collectors. IEEE Trans. On Electron Device, 2001, 48(1):24-31
[2]赵国骏,于毓麟,阮宝崧等.电子光学.北京:国防工业出版社,1980
[3]赵健闯,安健.强流脉冲电子束表面改性Al-Si-Pb合金摩擦学性能及数值模拟:硕士学位论文,吉林:吉林大学,2003
[4]王德,李春旭.空间电子束焊枪电子光学系统的设计:硕士学位论文,兰州:兰州理工大学,2004
[5]王汉斌,许州,黎明等.单晶LaB6阴极直流发射特性实验研究和强流电子枪及加速管物理研究:硕士学位论文,北京:中国工程物理研究院,2005
[6]廖平,杨海中.行波管电子光学系统CAD技术研究:博士学位论文,成都:电子科技大学,2003
[7] Robert J. Barker Edl Schamiloglu.高功率微波源与技术,北京:清华大学出版社2005
[8]成建波,冉启钧.六硼化镧阴极,成都:成都电讯工程学院出版社,1988
[9]翟兴林等.高亮度注入器电子枪研制,强激光与离子束,1994,6(3): 419-422
[10] H.Ahmed, A.N.Broers. Lanthanum Hexaboride Electon Emitter, Appl Phys,1972,43(5): 2185- 2192
[11] K.N.Leung, P.A.Pincosy, K.W.Ehlers. Directly Heated Lanthanum Hexaboride Filaments. Rev Sci Instrum, 1984,55(7):1064-1068
[12] Longo R. A Study of Thermal Emitters in the Regime of Practical Operation[A]. Proc Int Electron Devices Meet.1980:467-470.
[13]光电信息学院.阴极电子学讲义.2004
[14] MARC E, HERNITER, WARD D, et al. High Current Density Results From a LaB6 Thermionic Cathode Electron Gun,IEEE TRANSACTIONS ON PLASMA SCIENCE.VOL 18.NO.6.DECEMBER 1990
[15] MARC E, HERNITER, WARD D, et al. Thermionic Cathode Electron Gun for High Current Density, IEEE TRANSACTIONS ON PLASMA SCIENCE. VOL PS-15. NO. 4. AUGUST 1987
[16]盛新庆.计算电磁学要论.北京:科学出版社,2005
[17] S. Michizono, H.Tsutsui, S. Matsumoto, et al. ELECTRON GUN SIMULATION USING MAGIC: Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 Japan
[18] http://www.mrcwdc.com/Magic/toolsuite.html
[19] B.Goplen, L.Ludeking, David Smithe, et al. User-configurable MAGIC for electromagnetic PIC calculations. ELSEVIER: Computer Physics Communications 87 (1995) 54-86
[20]奎克,赛尔达著,韩郑生译.半导体制造技术.电子工业出版社.2004
[21] W.B.Herrmannsfeldt. NUMERICAL DESIGN OF ELECTRON GUNS AND SPACE CHARGE LIMITED TRANSPORT SYSTEMS. SLAC-PUB-2631 October 1980
[22]罗德均,祁康成,林祖伦,等.强流静电会聚电子枪系统计算机模拟研究,电子器件(已录用,近期发表)
[23] http//www.sd-wit.com/amd/LaB6.htm 2004
[24] D.M.Goebel, Y.Hirooka, T.A.Sketchley. Large-area Lanthanum Hexaboride Electon Emitter. Rev Sci Instrum,1985,56(9):1717-1722
[25]童林夙,西门纪业,电子光学系统计算机辅助设计,北京:国防工业出版社,1990
[26]王小菊,林祖伦.场发射阴极的计算机模拟:硕士学位论文,成都:电子科技大学,2003
[27]孙伯尧等.电子离子光学计算机辅助设计,北京:清华大学出版社,1991
[28]承欢,江剑平.阴极电子学,北京:电子工业出版社,1983
[29]刘盛纲,微波电子学导论,北京:国防工业出版社,1985
[30]《电子工业生产技术手册》编委会,电子工业生产技术手册(四)电真空器件卷,1991,648-649
[31] A.Yutani, A.Kobayashi, A.Kinbara. Work functions of thin LaB6 films.Applied Surface Science 70/71(1993)737-741
[32]廖复疆.真空电子技术.北京:国防工业出版社,2001
[33] M.A.KhakooJr, S.K.Srivastava. A compact high current pulsed electron gun with subnanosecond electron pulse widths. J. Phys. E: Sci. Instrum., Vol. 17, 1984
[34] J. J. Watrousa, J. W. Lugisland , G. E. Sasser. An improved space-charge-limited emission algorithm for use in particle-in-cell codes. PHYSICS OF PLASMAS Vol 8, 2001
[35]黄运添,郑德修.电子材料与工艺学.西安交通大学出版社.1990
[37] http://www.china-machine.comladv technologylkey_teclkey_item49.htm 2005
[38]何成旦等.电子枪新型阴极的设计.甘肃工业大学学报,2003, 29(3):1-5.
[39]电子管设计手册编委会.行波管电子光学系统设计手册.北京:国防工业出版社,1981
[40]电子管设计手册编委会.微波电子管磁路设计手册.北京:国防工业出版社,1984
[41] Dionne N.J,et al. Three-Dimensional Simulation of Gridded TWT Guns, Tech.Dig.Int.Eletron
[42] Devices Meeting, Washinton,D.C.,1980:479-482[26] Mankofsky A.. Linear accelerator and beam optics codes. A.I.P. Conf. Proc. No.177. New York,NY, 1988
[43] Petillo J, Eppley K, Panagos D, et al. The MICHELLE Three-Dimensional Electron Gun andCollector Modeling Tool:Theory and Design. IEEE Trans on PS,2002,30(3):1238-1264
[44] Petillo J, et al. 3-D Particle-in-cell Simulations for Multi-stage Depressed Collector Design,Proc 1988 Microwave Power Tube Conf., Monterey, CA,1988,2C-5
[45] Coco S, Emma F, Laudani A, et al. COCA: A Novel 3-D FE Simulator for the Design of TWTs Multistage Collectors. IEEE Trans. On Electron Device, 2001, 48(1):24-31