基于移动式脉冲高频电压的强流重离子束流堆积方法研究

Higher and higher intensity of heavy ion accelerators are required for experiments in the atomic physics, nuclear physics, plasma physics, energy materials and other subject areas especially in the high energy density physics and nuclear astrophysics. In the case of low energy and high stacked beam intensity, it’s hard to reach a high beam intensity as the space charge effect will lead to serious beam loss. While in the case of high energy, the traditional bucket to bucket stacking scheme between synchrotrons also cannot get a high intensity because of the limitation of circumference ratio. So a new beam stacking scheme must be investigated to meet the intensity requirement. This project proposes a new stacking scheme for high intensity heavy-ion beam based on pulsed radio frequency technique. It breaks through the limitation of circumference ratio by beam operation in longitudinal phase space adiabatically. This scheme has not been used in any existing heavy-ion accelerators distributed worldwide. So the first thing to do is beam dynamics research, especially influence of space charge effect on the phase space distribution of the beam and the beam-loss mechanism caused by space charge effect. Then it’s also necessary to optimize the modulation function of amplitude and phase. And the particle tracking code has 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. At last the simulation results will be verified experimentally.

原子物理、核物理、等离子体物理、新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蓬勃发展，对重离子加速器提供的流强要求越来越高。低能高堆积流强下，束流空间电荷效应会造成严重的束流损失，无法满足流强增益要求；高能下传统的纵向稳定区到纵向稳定区（bucket to bucket）的束流堆积方法，受前后级同步加速器周长比的限制，也达不到增益要求。因此，必须提出新的注入堆积方法。本项目拟采用移动式脉冲高频技术，通过在纵向相空间对束流绝热操纵，突破同步加速器周长比限制，达到强流重离子束流堆积目标。该方法是一种全新的束流堆积方法，目前尚未成熟，需要深入研究其束流动力学，特别是强流情况下空间电荷效应对束流相空间分布的影响和导致束流损失的机制，优化脉冲高频波形的幅度、相位调制函数，开发数值模拟程序研究束流堆积过程，找到影响束流堆积速度及效率的关键因素和解决方案，并对模拟结果进行实验验证。

原子物理、核物理、等离子体物理、新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蓬勃发展，对重离子加速器提供的流强要求越来越高。为了避免低能束流累积空间电荷效应引起的束流损失，同时克服同步加速器间周长比对束流堆积增益的限制，本文提出通过移动式脉冲高频技术，在纵向相空间对束流进行绝热操作，实现高累积增益。本项目对该堆积方法动力学进行了理论分析，数学建模，并在强流束流动力学模拟平台CISP上添加了脉冲式高频模块，实现对SRing上束流堆积的模拟，以及对移动式脉冲相位波形和电压波形的优化，在SRing接受度范围内实现4倍束流累积增益，满足了HIAF-SRing设计需求。同时完成了同步加速器间踢轨磁铁控制器逻辑研究和验证，实现前后两级同步加速器中纵向状态的精准捕获。