100MeV回旋加速器中心区实验台架的磁场测量和垫补
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摘要
随着科技的发展以及人们对强流束需求的提高，人们对经典回旋加速器的关注度变得越来越小，紧凑型强流回旋加速器因为其自身的优点越来越受到人们的关注。然而，紧凑型强流回旋加速器因为其磁极间气隙小，所以主磁铁的内部缺陷、机械加工的误差和安装误差等等因素对中心平面的磁场分布的影响就相对明显，因此，实际的磁场难免会偏离理想的等时性磁场，且这些因素所产生的某些非理想谐波场也是影响加速器束流品质的主要原因。只有通过对中心平面的磁场分布进行测量和垫补，才能有效的减少或者消除非理想场，提高加速器引出束流的品质。
本课题结合了中国原子能科学研究院串列升级工程中100MeV紧凑型强流回旋加速器的设计和建造而完成的。在100MeV回旋加速器中，粒子的加速圈数大约为450圈，为了获得好的束流品质，要求的粒子的积分滑相控制在±30°之内，即要求中心平面的磁场误差△B／B＜1.18×E-04。对于原有的CYCIAE-30回旋加速器的磁场测量系统的设计方法是无法完成上述要求的。因此，只有通过对100MeV回旋加速器中心区实验台架的磁场进行测量和垫补实验，掌握一种可以满足100MeV回旋加速器磁场测量精度要求的磁场测量系统的设计技术；同时，研究和实践一种能够有效的对一次谐波场进行垫补的方法。
中心区实验台架磁场测量和垫补的目标是：磁场基本满足等时场，束流的积分滑相控制在±20°内；一次谐波垫补后，在束流引出区附近和中心区附近的一次谐波场幅值小于15高斯，在其它半径幅值小于5高斯。
本课题的内容主要涉及霍尔感应磁场测量系统，磁场的测量，磁场测量数据分析，根据测量数据分析结果给出主磁铁镶条的加工量，以及磁场一次谐波垫补的方法和结果。
With the development of science and technology, along with the higher demand placed on high intensity beam, people have gradually transferred their focus from classical cyclotron to high intensity compact cyclotron, which have a number of advantages. However, because of the intrinsic asymmetry of the magnet, imperfection of the machining, magnet assembly error and other factors, the real field in median plane will easily depart from the isochronous filed in compact cyclotron with a very small gap. In the meantime, the imperfection field resulted from those factors is the main reason to affect the quality of accelerated beam. Only through measurement and shimming can the imperfection field be effectively reduced or avoided.
The task was correlated with the construction of a 100MeV compact cyclotron undergone at China Institute of Atomic Energy (CIAE). In the cyclotron, the particles will be accelerated about 450 turns. In order to obtain a good beam quality, the integral phase shift of centre particle will be controlled within±30°, that is to say, the field error in median plane is smaller than 1.18×E-04. Obviously the old design method of mapping system in CYCIAE-30 could not meet the above requirement. By the measurement and shimming to centre region model (CRM) cyclotron, we expect to grasp the design method of mapping system which will be used in 100MeV compact cyclotron. Meanwhile, we can study and apply the shimming method to the first harmonic field in compact cyclotron.
The final goal for the measurement and shimming to CRM is to achieve the following results: the field will be basically close to the isochronous field, and the integral phase shift will be controlled within±20°; after shimming to the first harmonic field, the amplitude of the first harmonic field will be less than 15 gauss around the extraction region and centre region, while in other region the amplitude will be less than 5 gauss.
The task of this research involves the hall probe measurement system, the measurement to magnetic field, the analysis to the field data, the machining size of shimming bars according to the analytical data and the method to shim the first harmonic field.
本课题结合了中国原子能科学研究院串列升级工程中100MeV紧凑型强流回旋加速器的设计和建造而完成的。在100MeV回旋加速器中，粒子的加速圈数大约为450圈，为了获得好的束流品质，要求的粒子的积分滑相控制在±30°之内，即要求中心平面的磁场误差△B／B＜1.18×E-04。对于原有的CYCIAE-30回旋加速器的磁场测量系统的设计方法是无法完成上述要求的。因此，只有通过对100MeV回旋加速器中心区实验台架的磁场进行测量和垫补实验，掌握一种可以满足100MeV回旋加速器磁场测量精度要求的磁场测量系统的设计技术；同时，研究和实践一种能够有效的对一次谐波场进行垫补的方法。
中心区实验台架磁场测量和垫补的目标是：磁场基本满足等时场，束流的积分滑相控制在±20°内；一次谐波垫补后，在束流引出区附近和中心区附近的一次谐波场幅值小于15高斯，在其它半径幅值小于5高斯。
本课题的内容主要涉及霍尔感应磁场测量系统，磁场的测量，磁场测量数据分析，根据测量数据分析结果给出主磁铁镶条的加工量，以及磁场一次谐波垫补的方法和结果。
With the development of science and technology, along with the higher demand placed on high intensity beam, people have gradually transferred their focus from classical cyclotron to high intensity compact cyclotron, which have a number of advantages. However, because of the intrinsic asymmetry of the magnet, imperfection of the machining, magnet assembly error and other factors, the real field in median plane will easily depart from the isochronous filed in compact cyclotron with a very small gap. In the meantime, the imperfection field resulted from those factors is the main reason to affect the quality of accelerated beam. Only through measurement and shimming can the imperfection field be effectively reduced or avoided.
The task was correlated with the construction of a 100MeV compact cyclotron undergone at China Institute of Atomic Energy (CIAE). In the cyclotron, the particles will be accelerated about 450 turns. In order to obtain a good beam quality, the integral phase shift of centre particle will be controlled within±30°, that is to say, the field error in median plane is smaller than 1.18×E-04. Obviously the old design method of mapping system in CYCIAE-30 could not meet the above requirement. By the measurement and shimming to centre region model (CRM) cyclotron, we expect to grasp the design method of mapping system which will be used in 100MeV compact cyclotron. Meanwhile, we can study and apply the shimming method to the first harmonic field in compact cyclotron.
The final goal for the measurement and shimming to CRM is to achieve the following results: the field will be basically close to the isochronous field, and the integral phase shift will be controlled within±20°; after shimming to the first harmonic field, the amplitude of the first harmonic field will be less than 15 gauss around the extraction region and centre region, while in other region the amplitude will be less than 5 gauss.
The task of this research involves the hall probe measurement system, the measurement to magnetic field, the analysis to the field data, the machining size of shimming bars according to the analytical data and the method to shim the first harmonic field.
引文
[1] “100MeV强流质子回旋加速器总体初步设计”，BRIF-C-B00-01．SM，中国原子能科学研究院，2006-05-09
[2] “100MeV强流质子回旋加速器磁场测量系统初步设计”，BRIF-C-B11-01-SM，中国原子能科学研究院，2006-05-11
[3] 陶启俊等，“CYCIAE-30回旋加速器测磁系统”，中国原子能科学研究院，档案资料，1994-08-25
[4] A.Papash , T.Zhang FIELD SHIMMING OF COMMERCIAL CYCLOTRONS. Cyclotrons 2004 Conference proceedings, Table of Contents, BEAM DYNAMICS
[5] Bill Gyles, private conversation, 2005-12
[6] 樊明武等，“CYCIAE-30回旋加速器主磁铁再计算、再设计以及加工、安装、磁场测量与垫补”，中国原子能科学研究院，档案资料，1995-10
[7] OPERA-3D Reference Manual，2004-02
[8] ANSYS,Inc.ANSYS Tutorials for Release 5.5.Forth Edition.SAS,IP Inc.1997
[9] 张恒喜，郭基联，朱家元，虞健飞．小样本多元数据分析方法及应用，西北工业大学出版社，2002-09
[10] 王川，“等时性回旋加速器磁场测量及垫补算法研究”，清华大学，2006-07
[11] L. Bottura, K. N. Henrichsen, FIELD MEASUREMENTS, CERN, Reneva, Switzland
[12] P. J. Bryant, BASIC THEORY FOR MAGNETIC MEASUREMENTS, CERN, Geneva, Switzerland.
[13] K. N. Henrichsen, CLASSIFICATION OF MAGNETIC MEASUREMENT METHODS, CERN, Geneva, Switzerland.
[14] B. Berkes. HALL GENERATORS, Paul Scherrer Institute, Villigen & Wuerenlingen, Switzerland
[15] 毛振珑，磁场测量，原子能出版社，55-97，1985-05
[16] "SPIRAL project: status of the cyclotron", M. Duval, M. P. Bourgarel, GANIL
[17] 何源，CSR磁场测量系统，中科院近代物理研究所，2003-6-26
[18] 姚红娟等，100MeV回旋加速器中心区实验台架上注入线设计、加工及安装，中国原子能科学研究院年报，2006，(待发表)
[19] 韩云端等，微积分教程，清华大学出版社，1999-9，369-372
[20] Bill Gyles, Magnet mapping and shimming, report in china, 2005-12
[21] Group3 User's Manual for DTM series Digital Tesla-meters
[22] Calibration Table for Probe Model LPT-141-30
[23] Calibration Table for Probe Model LPT-141
[24] 唐靖宇，等时性回旋加速器的理论和设计，1997-03-04
[25] M.M.Gordon, Calculation of isochronous field for sector-focused cyclotron, Particle Accelerators, 1983
[26] 陈佳洱《加速器物理基础》北京：原子能出版社，1993
[27] 桂伟燮，荷电粒子加速器原理，94-96，1994-03
[28] C.Baumgarten, Cyclotron-Some Relation, ACCEL Instrument GmbH, March 25, 2004
[29] Pauli Heikkinen, CYCLOTRONS, University of Jyvaskyla, Accelerator Laboratory, Jyvaskyla, Finland
[30] M.M.Gordon, Computation of closed orbit and basic focusing properties for sector-focused cyclotrons and the design of 'CYCLOPD', Particle Accelerators, 39-62, 1984.
[31] 关遐令，加速器六维束流光学，1992-02
[32] P. G. WATSON, DEVELOPMENT OF THE MAGNETIC CONE FOR THE CENTER OF THE BERKELEY 88-INCH CYCLOTRON, ICC (1962)
[33] 赵凯华，陈熙谋，电磁学(下册)，612-620，1985-06
[34] W. Kleeven, W. Beeckman, S. Lucas, S. Zaremba, D. Vandeplassche, and Y. Jongen. Magnetic field calculation and shimming of the self-extraction cyclotron 。 American Institute of Physics Conference Proceedings, December 12, 2001, Volume 600, Issue 1,348～350
[35] W.Kleeven, The influence of Magnetic field imperfection on the transverse orbit behavior in the TR-30 H Cyclotron, TR30-DN-15, 1988-12.
[36] Alexandr Papash, Radial and vertical orbit beahavior in TR13 H cyclotron due to magnetic field imperfection, TRI-DN-93-06, 1993
[2] “100MeV强流质子回旋加速器磁场测量系统初步设计”，BRIF-C-B11-01-SM，中国原子能科学研究院，2006-05-11
[3] 陶启俊等，“CYCIAE-30回旋加速器测磁系统”，中国原子能科学研究院，档案资料，1994-08-25
[4] A.Papash , T.Zhang FIELD SHIMMING OF COMMERCIAL CYCLOTRONS. Cyclotrons 2004 Conference proceedings, Table of Contents, BEAM DYNAMICS
[5] Bill Gyles, private conversation, 2005-12
[6] 樊明武等，“CYCIAE-30回旋加速器主磁铁再计算、再设计以及加工、安装、磁场测量与垫补”，中国原子能科学研究院，档案资料，1995-10
[7] OPERA-3D Reference Manual，2004-02
[8] ANSYS,Inc.ANSYS Tutorials for Release 5.5.Forth Edition.SAS,IP Inc.1997
[9] 张恒喜，郭基联，朱家元，虞健飞．小样本多元数据分析方法及应用，西北工业大学出版社，2002-09
[10] 王川，“等时性回旋加速器磁场测量及垫补算法研究”，清华大学，2006-07
[11] L. Bottura, K. N. Henrichsen, FIELD MEASUREMENTS, CERN, Reneva, Switzland
[12] P. J. Bryant, BASIC THEORY FOR MAGNETIC MEASUREMENTS, CERN, Geneva, Switzerland.
[13] K. N. Henrichsen, CLASSIFICATION OF MAGNETIC MEASUREMENT METHODS, CERN, Geneva, Switzerland.
[14] B. Berkes. HALL GENERATORS, Paul Scherrer Institute, Villigen & Wuerenlingen, Switzerland
[15] 毛振珑，磁场测量，原子能出版社，55-97，1985-05
[16] "SPIRAL project: status of the cyclotron", M. Duval, M. P. Bourgarel, GANIL
[17] 何源，CSR磁场测量系统，中科院近代物理研究所，2003-6-26
[18] 姚红娟等，100MeV回旋加速器中心区实验台架上注入线设计、加工及安装，中国原子能科学研究院年报，2006，(待发表)
[19] 韩云端等，微积分教程，清华大学出版社，1999-9，369-372
[20] Bill Gyles, Magnet mapping and shimming, report in china, 2005-12
[21] Group3 User's Manual for DTM series Digital Tesla-meters
[22] Calibration Table for Probe Model LPT-141-30
[23] Calibration Table for Probe Model LPT-141
[24] 唐靖宇，等时性回旋加速器的理论和设计，1997-03-04
[25] M.M.Gordon, Calculation of isochronous field for sector-focused cyclotron, Particle Accelerators, 1983
[26] 陈佳洱《加速器物理基础》北京：原子能出版社，1993
[27] 桂伟燮，荷电粒子加速器原理，94-96，1994-03
[28] C.Baumgarten, Cyclotron-Some Relation, ACCEL Instrument GmbH, March 25, 2004
[29] Pauli Heikkinen, CYCLOTRONS, University of Jyvaskyla, Accelerator Laboratory, Jyvaskyla, Finland
[30] M.M.Gordon, Computation of closed orbit and basic focusing properties for sector-focused cyclotrons and the design of 'CYCLOPD', Particle Accelerators, 39-62, 1984.
[31] 关遐令，加速器六维束流光学，1992-02
[32] P. G. WATSON, DEVELOPMENT OF THE MAGNETIC CONE FOR THE CENTER OF THE BERKELEY 88-INCH CYCLOTRON, ICC (1962)
[33] 赵凯华，陈熙谋，电磁学(下册)，612-620，1985-06
[34] W. Kleeven, W. Beeckman, S. Lucas, S. Zaremba, D. Vandeplassche, and Y. Jongen. Magnetic field calculation and shimming of the self-extraction cyclotron 。 American Institute of Physics Conference Proceedings, December 12, 2001, Volume 600, Issue 1,348～350
[35] W.Kleeven, The influence of Magnetic field imperfection on the transverse orbit behavior in the TR-30 H Cyclotron, TR30-DN-15, 1988-12.
[36] Alexandr Papash, Radial and vertical orbit beahavior in TR13 H cyclotron due to magnetic field imperfection, TRI-DN-93-06, 1993