强流重离子加速器中束流注入累积新方法研究

Higher and higher intensity of heavy ion accelerators are required for experiments in the atomic physics, particle physics, plasma physics, energy materials and other subject areas especially in the high energy density physics and nuclear astrophysics. In the case of limited injector intensity, the conventional multi-turn injection scheme cannot reach such a high intensity because of its low intensity gain. Furthermore, the conventional multi-multiturn injection scheme cannot help due to its requirement of long cooling time which will lead to considerable beam loss under the condition of strong space charge effect in the case of high intensity. New injection and accumulation scheme must be investigated to meet the intensity requirement. This project proposes a new accumulation scheme in which both horizontal and vertical phase space are explored simultaneously. This scheme has not been used in any existing heavy-ion accelerators distributed worldwide. So it have to be modeled with special attention paid to the influence of space charge effect on the phase space distribution of the beam and the beam-loss scheme caused by space charge effect. And the particle tracking code have to be developed to simulate the accumulation process in detail, with which the critical factor affecting the accumulation and the corresponding solution can be found. The optimized parameters related to the injection and accumulation will be studied as well. And the simulation results will be verified experimentally.

原子核物理、粒子物理、等离子体物理、能源材料等学科领域，特别是高能量密度物理和核天体物理的发展，对重离子加速器流强要求越来越高。在注入器流强有限的情况下，传统的多圈注入方法由于其流强增益较低，已不能满足要求；而且在低能高累积流强情况下，传统的多次多圈注入所需要的束流冷却时间较长，束流空间电荷效应会造成严重的束流损失，亦不可行。因此，必须提出新的注入累积方法来达到流强要求。本项目拟采用水平和垂直二维横向相空间同时涂抹的方法达到上述束流累积目标。该方法是一种新的束流累积方法，在目前世界上存在的重离子加速器中均未使用，需要对其建模，其中需特别考虑强流情况下空间电荷效应对束流相空间分布的影响和空间电荷效应导致的束流损失机制，开发粒子跟踪软件来模拟研究束流的累积过程，找到影响强流重离子累积的关键因素和解决方案，提出并优化注入累积相关参数，并对模拟结果进行实验验证。

原子核物理、粒子物理、等离子体物理、能源材料等学科领域，特别是高能量密度物理和核天体物理的发展，对重离子加速器流强要求越来越高。为避免在低能强流情况下，利用电子冷却系统进行长时间累积由于空间电荷效应导致的束流损失，本项目提出了一种新的可以在极短时间内（毫秒量级）进行高增益束流累积的方法，称为双向相空间涂抹注入方法。本项目对该注入方法进行了理论分析，数学建模，并编写了粒子跟踪模拟程序TPIS对注入过程进行了模拟，开发了智能优化算法PSO对注入参数进行了优化，通过对ORBIT程序的修改，使其支持双向相空间涂抹注入的模拟，并研究了强流情况下空间电荷效应对注入效率和粒子数增益的影响，而且在包含空间电荷效应的情况下对注入参数进行了优化，最终粒子数增益达到95，粒子损失可以控制在5%以下，实际粒子数达到1.64E11，达到HIAF-BRing设计要求。