低能强流重离子束流四维发射度的精确测量

Based on our many-channel picoammeter system, a new scheme of 4D-emittance measurement of low-energy high-intensity heavy-ion beams is proposed, in which one order-of-magnitude higher precision can be expected. Employing this scheme, we plan to measure the 4D-emittance of the ion beam extracted from the SECRAL-II superconducting ECR ion source. The dependence on the ion species, the charge state, the beam intensity, the beam energy, the magnetic fields of the ion source, and the focusing solenoid field behind exaction will be systematically investigated, and the relevance will be sought as well as a physics model will be attempted. The beam coupling effect in the transverse phase-space from the ECR ion source will be focused on. The present project will provide a beam-diagnostic gauge for the beam-property optimization in the development of the 4th generation ECR ion source, and offer consultations for beam dynamics design of the low-energy beam transport line in large heavy-ion accelerators.

基于我们发展的多通道皮安计系统，提出了一种测量低能高电荷态重离子束四维发射度的新方案，有望将测量精度提高一个数量级。拟利用该方案，系统地实验测量我所SECRAL-II超导ECR离子源引出束的四维发射度，研究其对离子束种类、电荷态、流强、引出能量、源体磁场参数、引出聚焦场参数等因素的依赖关系，并总结规律、建立物理模型。其中，我们将着重研究ECR引出束在横向相空间中的耦合问题。本项目将为正在研发中的第四代ECR离子源的束流品质提升提供诊断依据；为大型重离子加速器系统低能传输段的束流动力学设计提供参考。

依据大科学装置关于离子源前端四维发射度测量需求，本项目基于多通道皮安计系统设计研发了适用于离子源前端引出低能量强流高电荷态重离子束流四维发射度测量装置，并开发了一套适用于多通道皮安计的四维发射度的数据处理算法。项目实验研究了多通道皮安计获取离子源前端引出离子束流密度的可行性。通过本项目的实施，可为离子源前端引出束流的四维发射度的测量提供了一种新的方案，为离子源前端束流动力学的设计提供精确的四维发射度数据支持。