Time-resolved measurements of multiply charged ions in an EBIT including excitation by LCLS x-rays pulses

时间分辨率为高电荷离子物理学中的各种问题提供了新的见解。一个方面是研究波函数组成及其对外部磁场的敏感性，在光谱Fe XVII中进行测试。在电子束离子阱（EBIT）中，通过微秒范围内的原子寿命来测量J=0-0跃迁（通常严格禁止）的磁场依赖性发生。相比之下，同一原子系统中的一对突出的3D能级（3C/3D问题）需要通过可调节的强X射线脉冲对进行激发，其到达时间差为数十飞秒。这个实验目前只能在SLAC（斯坦福大学，加利福尼亚州，美国）的直线加速器相干光源（LCLS）上进行，由MPI-K海德堡和劳伦斯利弗莫尔国家实验室（LLNL）团队联合运行的旅行EBIT。随后的测量，与LCLS性能的改进，将测量两个电子（类氦）离子的共振线的衰减率。

Time resolution offers new insights into various problems in the physics of highly charged ions. One aspect is the study of wave function composition and its susceptibility to external magnetic fields, with test cases in the spectrum Fe XVII. The magnetic-field dependent occurrence of a J=0-0 transition (usually strictly forbidden) is to be measured in an electron beam ion trap (EBIT) via atomic lifetimes in the microsecond range. A prominent pair of 3d levels in the same atomic system (the 3C/3D problem) in contrast requires excitation by adjustable pairs of intense x-ray pulses with an arrival time difference on the scale of dozens of femtoseconds. This experiment can presently be tried only at the Linac Coherent Light Source (LCLS) at SLAC (Stanford, CA, USA) with a traveling EBIT jointly run by a MPI–K Heidelberg and Lawrence Livermore National Laboratory (LLNL) team. A subsequent measurement, in step with LCLS performance improvements, will measure the decay rate of the resonance line in two-electron (heliumlike) ions.