重离子储存环上纵向肖特基频谱的模拟与分析

Longitudinal Schottky signal spectrum at heavy-ion storage ring:Simulation and analysis

重离子加速器冷却储存环为重离子物理及其交叉学科的研究提供了独一无二的实验平台.肖特基频谱系统作为其中最为重要的束流诊断装置之一,其获取的频谱信息不仅能够用于束流品质的非拦截式实时监测,而且可作为一个核心的观测工具而广泛地应用于束流冷却动力学分析、原子核基本性质测量等物理实验之中.本文结合理论推导和模拟分析,系统地研究了连续束纵向肖特基频谱的性质,重点分析了束团束纵向肖特基频谱的结构及其特性,并提出了一种新的由束团束肖特基频谱准确重构离子束动量分布的方法.最后,结合在储存环CSRe上所获得的纵向肖特基频谱,对模拟结果进行了实验验证.该研究将为储存环上相对论能量重离子束的激光冷却过程中的束流冷却动力学分析以及束流状态诊断奠定坚实的基础,并为基于肖特基频谱所开展的随机冷却、电子冷却以及原子的核质量和寿命测量等物理实验提供有力的技术支持.

The heavy-ion accelerator cooler storage ring provides a unique experimental platform for precision measurements with highly charged ions and interdisciplinary research.As one of the most powerful beam diagnostic devices,the Schottky resonator system can be used to nondestructively monitor beam qualities and as a critical instrument for various in-ring experiments,e.g.,analyzing of beam cooling dynamics and measuring the fundamental properties of exotic nuclei.In this article,the properties of the longitudinal Schottky signal spectrum of the coasting ion beam are studied via theoretical derivation and simulation analysis.On this basis,the structure and characteristics of the longitudinal Schottky signal spectrum of bunched ion beams are systematically simulated and analyzed.Furthermore,a new method is proposed and simulated for accurately reconstructing the momentum distribution of bunched ion beams from the longitudinal Schottky signal spectrum.Finally,the simulation results are verified with the experimentally measured longitudinal Schottky signal spectrum at the storage ring CSRe.These studies establish a solid foundation for analyzing cooling dynamics and beam property diagnostics during the laser cooling of relativistic bunched heavy-ion beams.Moreover,they strongly support other experiments based on the longitudinal Schottky signal spectrum,such as stochastic cooling,electron cooling,and nuclear mass and lifetime measurements.