高工作比、热阴极4+1/2腔微波电子枪研究
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摘要
长期以来,探索新型短脉冲、高亮度电子源倍受关注。热阴极微波电子枪
    (RF-gun)是新一代高亮度电子源,它具有结构简单、运行可靠、造价低廉等
    优点,高工作比、热阴极RF-gun的开发和应用研究受到广泛重视。本论文针对
    高工作比RF-gun中的电子反轰和束流负载两个主要问题,从理论和实验两个方
    面进行了详细研究,论证了RF-gun高工作比运行的可行性。论文还对国际最新
    发展的微脉冲电子枪(MPG)工作过程进行了分析,并提出了实验方案。
     论文首先分析了缩短首腔和第二腔腔长(就是加聚束段)对抑制反轰的作用,
    重点讨论了缩短首腔中的电子运动方程,发现对β_p<1的聚束腔,必须对Kim
    表达式进行修正。用RUNGE-KUTTA法求出电子运动方程的数值解,给出了缩
    短首腔对增加电子俘获系数、减小电子反轰比较清晰的物理图象。利用反轰加
    热LaB_6阴极,建立了加热功率热力学平衡方程,设计了灯丝加热反馈控制方法。
    实现了高工作比、热阴极RF-gun的稳定运行。此外,叙述了新型微脉冲电子枪
    中的二次电子倍增工作原理,给出了共振特征关系图,从电子运动方程独立推
    导了电子自聚束公式,从空间电荷限制出发,讨论了饱和电流,并结合实验室
    的现有条件,进行了MPG初步设计。这种电子源充分利用了RF腔中电子的反
    向运动,无灯丝加热,不怕暴露大气,高工作比,长寿命,具有光阴极和热阴
    极的优点,避开了它们的缺点,很有吸引力。
     论文用等效电路方法分析了高工作比RF-gun中的束流负载效应,把束流负
    载作为激励源来处理。讨论了束流负载对加速腔中电场、电子能量、加速腔谐
    振和失谐(detuning)的影响。给出了最佳耦合度公式,并将驻波加速器书中所得
    到的最佳耦合度公式进一步推导,得出与它相一致的结果,表述更简洁。给出
    了有束流负载时的最佳工作条件。论文还建立了微波源功率、束流强度、束流
    功率、加速腔壁耗、腔中电场强度、有效分路阻抗、无载耦合度等参数之间的
    用解析式表达的自治方程,并用该方程计算了4+1/2腔RF-gun的工作状态,与
    用PARMELA程序计算的结果基本相符,对RF-gun调试与状态分析有一定的
    指导意义。
     论文介绍了高工作比4+1/2加速腔的物理设计与束流动力学模拟计算结果。
    
    
     中 国 工程物理研究院
    叙述了腔的设计思想,用SUPEnyISH计算了腔的尺寸和主要特性参数,用
    PA删ELA程序进行了束流动力学分析,得出了不同首腔长度、实心阴极和空
    心阴极条件下的电子反轰情况和束斑、束径向尺寸、能谱、能量随相位分布等
    曲线。
     论文最后是高工作比、热阴极4刊a腔y呕un的实验研究,给出了冷测和
    热测主要参数。调束实验中我们对实验系统进行了许多大的改进,以满足高平
    均功率要求,主要是:提高微波源输出功率;改进了阴极加热灯丝结构;提高
    出束时腔内抽真空能力;增加陶瓷窗和法拉第筒的水冷措施等,在此基础上,
    新型4刊Q腔RF唱tm顺利出柬,在进腔微波功率3MW时,得到:宏脉冲束流
    强度400InA叫,脉冲宽度印,工作比5X10\IX10”‘,实验结果与理论计算相
    符。系统工作稳定性和进一步实验正在进行中。
The development of high-current ,short-pulses of electron bunches has been a
     challenging project for many years. The thermionic cathode RF-gun is a new kind of
     high brightness electron source. Its advantages are simple construction, operating
     reliablility and low cost. Because of these merits, the thermionic RF-guns have been
     widely used , such as the injector of linac and FEL experiments. Especially, the
     thermionic RF-gun with high duty factor(DF) have potential applications in the
     industry. This research effort is very attractive ,although there will be some
     difficulties during the progress. Two key physics issues pertinent to the development
     of high DF RF-gun ,they are the effects of the electron back bombardment and the
     beam loading. They have been studied in detail from the aspects of theory and
     experiments in this dissertation. The purpose of these studies is to demonstrate the
     possibility of the RE-gun operation with high DF. Recently , a novel concept of RF-
     gun micropulse electron gun is being developed in the USA. A tracing study idea is
     also presented in the dissertation.
     First of all, the suppression of electron back bombardment by shortening the first
     and the second cells has been analysed . The essence of shortening cavity length is to
     add the buncher section in the starting of RF-gun. I discovered Kim equation must be
     modified. The study was focused on the electron motion equation in the case
     3,     using the RUNGE-KUTTA method and the results indicate clearly that the electron
     back bombardment can be reduced and that the electron capture coefficient can be
     increased. The way to use the power of electron back bombardment to heating the
     cathode of the electron gun and the thermodynamics balance equation of the cathode
     heating power is discussed. In order to operate the RE-gun steadily, the auto-
     controlling negative feedback method is designed. Besides, the experiment project of
     MPG is proposed according to the conditions of our lab. Micro-bunches are produced
     by resonantly amplifying current of secondary electron in RE cavity. The phase
     self-bunching and the saturation current are deduced individually and discussed. The
     multipactor operating chart is given. The MPG is one kind of excellent RE-gun. It has
     brilliant future.
     The effects of beam loading have been studied by using the equivalent circuit. In
     this method ,the beam loading has been regarded as another driven source. The
     optimum coupling coefficient with beam loading is obtained. The detuning and the
     optimum operation condition are analysed .A consistent equation of the relation
     among the operating parameters is created. The analysing results of the 4+1/2 cells
     RE-gun using this equation are consistent with the results of the PARMELA program.
     The thermionic cathode 4+1/2 cells RE-gun with high DF is analysed .The shape
     size and cavity operating parameters of this RE-gun and beam dynamics calculation
     are given out using SUPERFISH and PARMELA programs.
     Finally, the cold test and powered experiments of this gun are carried out .The
    
    
    commissioning experiments are conducted in the D4064 klystron microwave testing
     bed. In order to meet the requirement of the commissioning , we have improved the
     experiment system and upgraded microwave output power. The commissioning of this
     new high DF 4+1/2 cells RE-gun is successful , we obtain experiment parameters are:
     the macropulse beam current is: 400mA A, the macropulse width is 5s, the DF is
     5x1OxlO3.These results are consistent with those pr
引文
1.A.Westenshop,J.M.J.Madey, "Microwave Electron Gun" ,Laser and Particle Beam, 1984,2(2),p223
    2.E.Tanabe, "A 2 MeV Microwave Thermionic Gun" ,SLAC PUB-5054(1989)
    3.Gao J and J.L.Xie, "RF-gun development at IHEP for BFEL" ,N.I.M in Phys.Res,A304 No 1-3 357,1991
    4.谢家麟等,高能物理与核物理,Vol.18(1994)p765-768
    5.M.Tukabe etc, "0.9MeV microwave electron gun system for FEL" ,N.I.M. in Phy. Rev.A318,Nol 1-3 p367(1992)
    6.刘锡三等,“S波段,1+1/2腔热阴极枪微波电子枪研究”,强激光与粒子束,6(2)1994,161-170
    7.Liu xisan etc. "L-Band 1+1/2 Cell Microwave Gun with LaB_6 Thermionic Cathode" , The Sixth China-Japan Joint Symposium on Accelerator for Nuclear Scince and Their Applications, 1996,10
    8.唐传祥等,“微波电子枪实验研究”,高能物理与核物理,1997.5
    9.M.Borland etc, "Performance of the 2MeV Microwave Gun for the SSRL 150MeV Linac" ,SLAC-PUB-5333(1991)
    10.A.Alimov ect, "Continuos Wave RF-gun" , EPAC 1994,P778
    11.许州,热阴极微波电子枪物理与实验研究,博士论文,中国工程物理研究院,1997
    12.唐传祥,用于BFEL的多腔热阴极微波电子枪研究,博士论文,清华大学工程物理系,1997
    13.T.W.Levellen etc,"A Thermionic Cathode RF-gun for Compact FEL Use",1995 International FEL Conference
    14.V.V.Mitroenko etc,"Thermionic RF-gun with High Duty Factor", IEEE International Particle Accelerator Conference 1998
    15.杨兴繁等,“高工作比、热阴极4+1/2腔RF-gun调试出束”,强激光与粒子束,已接受待发表,2000
    16.C.H.Lee etc IEEE Trans Nucl Sci NS-225 1985 p3045
    17.R.L.Sheffied etc, "RF Photoelectron Gun Experimental Performance" ,Proc Linear Accelerator Conf 1988 p520
    18.S.V.Benson,J.M.J.Madey etc, "Status report in the Stanford MarkⅢ infrared FEL" ,N.I.M. in Phy.Rev,A272,Nol-2 p22 1988
    19.D.W.Feldman etc, "Experiment Results from the Los A lamos FEL Photoinjector", Quantum electronics,Vol.27 No 12,p2636 1991
    
    
    20.A.H.Lumpkin etc, "Initial electron-beam Charact for the Los AlamosAPEX facility" ,N.I.M. in Phy.Res,A318Nos 1-3 (1992) 415
    21.K.C.D.Chan etc, "Los Alamos advanced free-electron Laser" ,N.I.M. in Phy. Res,A318,Nos 1-3 (1992)148
    22.Sanghyan Park, "A multi-cell RF Phtoinjector Design" ,PAC95,p948
    23.I.S.Lehrman etc, "Design and construction of a high duty factor phtocathode electron gun" ,PAC93,P3012
    24.H.Chaloupka etc, "A Proposed Supperconducting Photoemission Source of High Brightness" , EPAC88 p1312-1314 1988
    25.L.K.Len and F.M.Mako,"Self Bunching Electron Gun",PAC99 1999p70
    26.许州,1+1/2腔RF-gun腔型优化设计与动力学研究,硕士论文,中国工程物理研究院,1991
    27.章林文,L波段高亮度注入器腔型的理论设计与实验研究,博士论文,中国工程物理研究院,1995
    28.C.B.Mckee and John M.J.Madey, "Optimization of a thermionic microwave gun" ,N.I.M. A304(1991) p.386-391
    29.V.A.Kushnir, V.V.Mitrochenko, "Simulation of beam performance of the two-cell RF gun" ,Proc of the fifth European Particai Accelerator Conference,Sitges(Barceloma), 10 to 14 June 1996, p. 1414-1416
    30.H.Kobayashi et al., "Development of Microwave Electron Gun with a Mesh Grid" ,in Japanese,JAP89
    31.M.Borland, "An improved thermonic microwave gun and emittance-preserving transport line" , 1993 Partical Accelerator Conference p.3015-3017
    32.顾本广等,“驻波加速管中电子反轰现象”,强激光与粒子束,Vol.3No.3,1991
    33.许州等,“热阴极微波电子枪反轰现象研究”,强激光与粒子束,Vol4 1996
    34.唐传祥,林郁正,“关于热阴极微波电子枪中电子反轰问题的研究”,强激光与粒子束,Vol.8,No.1,1996
    35.M.Borland,A high brightness thermionic microwave electron gun,SLAC-Report-402,1991
    36.K.J.Kim," RF AND SPACE-CHARGE EFFECS IN LASER-DRIVEN RF ELECTRON GUNS",N.I.M.A275(1989)201-218
    37.匡蛟勋译,数值方法引论,上海科学技术山版社,1986
    38.王书鸿,质子直线加速器原理,原子能山版社,1986.7
    39.Lipscomb.G.A,IEEE Trans Plasma Sci, 1989 17(6) p898
    40.C.B.Mckee and J.M.J.Madey, "Computer Simulation of Cathode Heating By Back Bombardment In The Microwave Electron Gun"
    
    
    41.NFZ-10工业辐照电子直线加速器研制报告,南京大学加速器研究所,1997
    42.J.R.M.Vaughan, "MULTIPACTOR" ,IEEE TRANSACTION ON ELECTRON DEVICE,Vol.35,NO.7 1988,p. 1172
    43.R.Kishek,Y.Y.Lau, "Interaction of impactor discharge and rf circuit" ,Phy. Rev.Lett.75,6,p. 1218 (1995)
    44.S.Riyopoulos etc, "Effects of random secondary delay times and emission velocities in electron multipactor" ,IEEE Tran. Elec. Device,44,p.489,1997
    45.A.J.Hatch etc, Phys. Rev, 1958 p681
    46.F.Mako ect, "Self-Bunching Electron Guns" , The Ameican Institude of Physics 1999
    47.刘学悫,阴极电子学,科学出版社,1980
    48.B.K.Agarwal, "Variation of Secondary Emission with Primary Electron Energy" ,Proc.Roy. SOC.71,p851,1958
    49.J.A.Nation etc.,Proc.of the IEEE,Vol.87,No.5,May 1999
    50.顾本广,低能电子直线加速器,北京医疗器械研究所,1985
    51.P.M.Lapostolle, Linear accelerator, 1970
    52.T.P.Wanger, Principles of RF Linera Accelerators, 1998
    53.S.Arai etc, "Beam-loading effects in a standing-wave structure,Particle accelerator" Vol. 11 p103-111,1980
    54.Takeshi Katayama etc, "Beam loading effect on capture efficiency in radio frequency in electron synchrotron" ,JJAP 1980,p2229-2238
    55.应嘉年,微波与光导波技术,国防工业出版社,1994
    56.林郁正,低能电子直线加速器原理,清华大学讲义(1990)
    57.姚充国,电子直线加速器,科学出版社,1986
    58.许州,4MeV4+1/2腔RF-gun设计报告,内部资料,1999
    59.L.M.Young, PARMELA,LANL 1998
    60.张克潜等,微波与光电子学的电磁理论,电子工业出版社,1994
    61.唐传祥,4MeV4+1/2腔RF-gun冷测报告,内部资料,1999
    62.蔡公和,“30MeV电子直线加速器的束流测量装置”,强激光与粒子束Vol.11 No.3,1999 p367-370

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