Courant-Snyder invariant density screening method for emittance analysis  

作　　者：孙纪磊 唐靖宇 敬罕涛 

机构地区：[1]Institute of High Energy Physics,Chinese Academy of Sciences

出　　处：《Chinese Physics C》2011年第11期1059-1065,共7页中国物理C（英文版）

基　　金：Supported by NSFC (10975150, 10775153);Major State Basic Research Development Program of China (2007CB209904)

摘　　要：Emittance is an important characteristic of describing charged particle beams. In hadron accelerators, we often meet irregular beam distributions that are not appropriately described by a single rms emittance or 95% emittance or total emittance. In this paper, it is pointed out that in many cases a beam halo should be described with very different Courant-Snyder parameters from the ones used for the beam core. A new method - the Courant-Snyder invariant density screening method - is introduced for analyzing emittance data clearly and accurately. The method treats the emittance data from both measurements and numerical simulations. The method uses the statistical distribution of the beam around each particle in phase space to mark its local density parameter, and then uses the density distribution to calculate the beam parameters such as the Courant-Snyder parameters and emittance for different beam boundary definitions. The method has been used in the calculations for beams from different sources, and shows its advantages over other methods. An application code based on the method including the graphic interface has also been designed.Emittance is an important characteristic of describing charged particle beams. In hadron accelerators, we often meet irregular beam distributions that are not appropriately described by a single rms emittance or 95% emittance or total emittance. In this paper, it is pointed out that in many cases a beam halo should be described with very different Courant-Snyder parameters from the ones used for the beam core. A new method - the Courant-Snyder invariant density screening method - is introduced for analyzing emittance data clearly and accurately. The method treats the emittance data from both measurements and numerical simulations. The method uses the statistical distribution of the beam around each particle in phase space to mark its local density parameter, and then uses the density distribution to calculate the beam parameters such as the Courant-Snyder parameters and emittance for different beam boundary definitions. The method has been used in the calculations for beams from different sources, and shows its advantages over other methods. An application code based on the method including the graphic interface has also been designed.

关 键 词：EMITTANCE Courant-Snyder invariant density Courant-Snyder parameters beam halo 

分 类 号：O572.211[理学—粒子物理与原子核物理]