Isochronicity correction in the CR storage ring
Isochronicity correction in the CR storage ring
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DOI：
10.1016/j.nima.2013.05.057
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发表时间：
2013-03
影响因子：
1.4
通讯作者：
S. Litvinov;D. Toprek;H. Weick;A.Dolinskii
中科院分区：
文献类型：
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作者：
S. Litvinov;D. Toprek;H. Weick;A.Dolinskii
核物理的一个挑战是测量奇异核的质量，直到核存在的极限，其特征是低生产截面和短半衰期。FAIR [2]的大接受收集环（CR）[1]在等离子光学模式下调谐，为测量短寿命和非常奇特的核素提供了独特的可能性。然而，在为最大接受度设计的戒指中，许多因素限制了分辨率。一点是时间分辨率的极限，与横向发射度成正比。但大部分时间像差可以被校正，而其他像差则会随着转动次数的增加而变小。我们显示的时间校正相应的横向聚焦的关系和大发射度的主要校正直接对应于光束的横向聚焦的色度校正。借助完全验收的蒙特-卡罗模拟，我们演示了如何校正旋转时间，以便在原则上可以实现Δ m/m= 10− 6的分辨率。在这些计算中，考虑了磁体不均匀性和扩展边缘场的影响，并提出了一种适用于不同质荷比离子的校准方案。
A challenge for nuclear physics is to measure masses of exotic nuclei up to the limits of nuclear existence which are characterized by low production cross-sections and short half-lives. The large acceptance Collector Ring (CR)[1] at FAIR [2] tuned in the isochronous ion-optical mode offers unique possibilities for measuring short-lived and very exotic nuclides. However, in a ring designed for maximal acceptance, many factors limit the resolution. One point is a limit in time resolution inversely proportional to the transverse emittance. But most of the time aberrations can be corrected and others become small for large number of turns. We show the relations of the time correction to the corresponding transverse focusing and that the main correction for large emittance corresponds directly to the chromaticity correction for transverse focusing of the beam. With the help of Monte-Carlo simulations for the full acceptance we demonstrate how to correct the revolution times so that in principle resolutions of Δ m/m= 10− 6 can be achieved. In these calculations the influence of magnet inhomogeneities and extended fringe fields are considered and a calibration scheme also for ions with different mass-to-charge ratio is presented.