HIAF-BRing极化质子加速方案研究

发布时间：2018-01-16 06:48

本文关键词：HIAF-BRing极化质子加速方案研究　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：对核子之间相互作用的理解是整个核物理以及强子物理的基础。核子-核子散射是研究核力的理想工具。开展极化实验可以测量完整的核子-核子散射观测量。因此为了更深入地研究核子性质,中国科学院近代物理研究所提出了在强流重离子加速器装置(HIAF)上利用极化质子束开展实验的计划。极化束流将会在同步加速器中做多次回旋运动,可能受到周期性磁场的扰动,在一定条件下,有些粒子的自旋将会翻转,这就是退极化现象。发生退极化现象,极化束流的极化度将会降低,甚至变得完全非极化。本文的工作就是要结合BRing的设计参数,设计一套合理的极化束加速方案,以保证在未来的极化实验中HIAF-BRing可以提供具有较高极化度的束流。在环形加速器中,由于离子的回旋运动,极化会周期性地受到扰动磁场的影响,发生退极化共振。退极化共振有很多种,例如非理想共振,固有共振,耦合共振,同步辐射边带共振,snake共振等。在本文的工作中忽略高阶共振,仅考虑两种主要的退极化共振——固有共振和非理想共振对束流极化度的影响。极化动力学由Thomas-BMT方程描述,同时,在Fernet-Serret曲线坐标下,利用Thomas-BMT方程我们研究了加速器中主要退极化共振的诱导因素,并推导了关于退极化强度的计算公式。HIAF增强器BRing将把极化质子束加速至9.3GeV/u,在整个加速过程中极化束流将会遇到多次退极化共振。根据我们的研究理论,计算了在BRing加速过程中不同退极化共振的强度。同时根据极化在穿越孤立共振时变化所满足的Froissart-Stora方程,编写程序计算了BRing中两种强的退极化共振对极化度的影响。结果表明:加速过程遇到的两种退极化共振将会使BRing中的极化束流完全退极化。目前常用的解决退极化共振的方法主要有:安装自旋旋转器,闭轨校正,tune jump和安装西伯利亚蛇磁铁系统。因为BRing的垂直工作点接近半整数,因此我们采取在BRing电子冷却段加入Full SiberianSnake磁铁系统的方法,克服固有共振和非理想共振,从而使质子束在加速时保持较高的极化度。同时螺线管引入的横向耦合效应也通过加入四极磁铁的方式被消除,完整的元件参数均已给出。这将是我国首次关于极化质子的加速研究,也为未来在HIAF上开展极化实验奠定了良好的基础。
[Abstract]:The understanding of nucleon interaction is the basis of the whole nuclear physics and Hadron physics. Nucleon-nucleon scattering is an ideal tool for studying nuclear force. Complete nucleon-nucleon scattering observations can be measured by polarization experiments. So in order to study nuclear properties more deeply. The Institute of Modern Physics of the Chinese Academy of Sciences has put forward the plan of using polarized proton beam to carry out experiments on the high current heavy ion accelerator (HIAF), which will perform many cyclotron motions in the synchrotron. Under certain conditions, the spin of some particles will be reversed, which is the phenomenon of depolarization, the polarization of the polarization beam will be reduced. The work of this paper is to design a set of reasonable polarization beam acceleration scheme combined with the design parameters of BRing. In order to ensure that in future polarization experiments HIAF-BRing can provide a beam with high polarizability. In the ring accelerator due to the cyclotron motion of ions. Polarization is periodically affected by the disturbed magnetic field and depolarized resonance occurs. There are many kinds of depolarization resonance, such as non-ideal resonance, inherent resonance, coupling resonance, synchrotron radiation sideband resonance. Snake resonance and so on. High order resonance is neglected in the work of this paper. Only two main depolarization resonances-natural resonance and non-ideal resonance are considered. The polarization dynamics is described by Thomas-BMT equation and at the same time. In the Fernet-Serret curvilinear coordinates, we study the inductive factors of the main depolarization resonance in the accelerator by using the Thomas-BMT equation. The formula of depolarization intensity is derived. The BRing of HIAF intensifier will accelerate the polarized proton beam to 9.3 GeV / u. During the whole acceleration process, the polarized beam will encounter multiple depolarization resonance. The intensity of different depolarization resonance during BRing acceleration is calculated, and the Froissart-Stora equation of polarization variation in the process of passing through the isolated resonance is given. The influence of two strong depolarization resonance in BRing on the polarization degree is calculated. The results show that:. Two kinds of depolarization resonance in the acceleration process will depolarize the polarized beam completely in BRing. At present, the commonly used method to solve depolarization resonance is to install spin rotator. Close orbit correction tune jump and install Siberian snake magnet system. BRing's vertical operating point is close to half an integer. Therefore, we adopt the method of adding Full SiberianSnake magnet system to the BRing electronic cooling section to overcome the inherent resonance and non-ideal resonance. The transverse coupling effect of solenoid is eliminated by adding quadrupole magnets. The complete parameters of the components have been given. This will be the first acceleration study of polarized protons in China and will lay a good foundation for future polarization experiments on HIAF.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O571

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