First steps towards atomic physics of fast ion-slow ion collisions

本项目的主要目的是研究快离子-慢离子碰撞中的基本原子过程。测量和可靠的理论预测是完全缺乏这样的碰撞在一个政权中，离子阻止功率是最高的，所有的主要电子过程（电子捕获，损失和激发）达到最大值。它对应于原子物理学的一个真实的未知领域。离子-离子碰撞是宇宙中普遍存在的现象之一，但在实验室中研究得最少。在良好的控制条件下，跨越两个多电荷离子束，一直是一个非常具有挑战性的任务，无论是在考虑的物理领域。法国和德国的大型加速器设施（SPIRAL 2和FAIR）即将提供高光学质量的强而稳定的离子束，这将最终允许将离子-离子碰撞研究扩展到上述区域。为了实现这一具有挑战性的目标，将建立一个独特的交叉束离子-离子实验装置，进行绝对截面测量。其中最严重的瓶颈，应该克服，我们可以强调的阻力的高能量离子束剥离的目标，交叉束的重叠和总体实验条件的控制，以优化多符合事件探测。为了实现这一目标，我们将开展专门的可行性研究：高强度束流（脉冲和连续）的剥离器概念，离子检测系统以及碰撞室中的束流控制和背景抑制。在这些研究的基础上，将设计、建造最佳实验装置并进行首次实验。在该项目中，与两个德国和两个法国合作伙伴建立的合作关系尤其适合以非常具体的技能和长期的合作传统来应对这一挑战。

The main aim of this project is to investigate fundamental atomic processes in fast ion-slow ion collisions. Measurements and reliable theoretical predictions are completely lacking for such collisions in a regime in which ion stopping power is highest, and all the primary electronic processes (electron capture, loss and excitation) reach their maximum. It corresponds to a real terra incognita for atomic physics. Ion-ion collisions are one of the widespread phenomena in the universe but the least studied in laboratory. Crossing two multicharged ion beams, under well controlled conditions, has always been a very challenging task whatever the domain of physics under consideration. The forthcoming availability of intense and stable ion beams of high optical quality on French and German Large Scale Accelerator Facilities (SPIRAL2 and FAIR) will finally allow to extend ion-ion collisions studies into the above mentioned regime.In order to achieve this challenging goal, a unique crossed beam ion-ion experimental setup, to perform absolute cross section measurements, will be built. Among the most severe bottlenecks that should be overcome, we can stress the resistance of the target for stripping of the high energy ion beam; the control of the overlap of the crossed beams and the mastership of the overall experimental conditions to optimize the multi-coincidence event detection. In order to accomplish this, we will carry out dedicated feasibility studies on: stripper concept for high intensity beams (pulsed and continous), ion detection systems as well as beam control and background suppression in the collision chamber. Based on these studies the optimal experimental setup will be designed, built and first experiments performed.The collaboration built within this project with two German and two French partners is particularly well positioned to take up this challenge with very specific skills but also a long-standing tradition of collaboration.