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Study of the Electron-Capture Phenomena in the Electron-Cooling Process of Highly-Charged Ions

高电荷离子电子冷却过程中电子俘获现象的研究

基本信息

批准号：
01460014
负责人：
TANABE Tetsumi
金额：
$ 3.33万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01460014/
关键词：
Electron cooling Electron capture Dielectronic recombination 重イオン中性粒子ビ-ム

项目摘要

For the electron-cooling process, ions merge with electrons at a part of the long straight sections of the storage-ring circumference. In this case, ions capture the cooling electrons at a certain probability. The particles which changed their charges in this way deviate from the main orbit of the ring and so it is easy to detect them. Such a charge-changed beam includes much important informations on electron and ion beams. Therefore, one can diagnose the accelerator by the detailed analysis of the charge-changed beam measurement.On the other hand, the electron-cooling section is the field where ions with good qualities interact with the electrons having relative velocities ranging from zero to a large value. In this sense, the cooling electrons can be regarded as a pure high-density electron target. The ion-electron interaction which is an important branch of atomic physics research can thus be studied by using these devices.Research was performed for three kinds of ions : 1) The ele … More ctron capture process of H^+ beam has well been known experimentally and also theoretically. Taking advantage of this fact, we studied the electron cooling process by observing the neutral hydrogen atoms created through electron-capture. From the capture rate, we could deduce the electron temperature as 0.2 eV. On the other hand, from the measurement of the neutral beam 「rofile, the emittance of the circulating cooled-beam was found to be 1-2 pi mmmrad. Furthermore, for the bunched beam, the bunch width was estimated by the measurement of the distribution of the arrival times of neutral atoms at the detector. The width was a few ten nsec, which contrast to the initial width of a few hundreds nsec. 2) For the electron capture studies on H_2 ^+ ion. a pair of hydrogen atoms were observed, which come from the dissociative recombination process H_2 ^++e--H+H. From the detailed analysis, the intersection angle between electron and ion beams was estimated. 3) For the studies on the electron capture of ^3He ^+ ion, the dielectronic recombination process was first observed. It is the process in which already attached electron in ^3He ^+ is also excited from 1s to 2p state at the save time that a ferr electron is captured. The result is consistent with a theoretical prediction. In future, we wish to extend these studies to heavier ions. Less

对于电子冷却过程，离子与电子在储存环圆周的长直部分的一部分处合并。在这种情况下，离子以一定的概率捕获冷却电子。以这种方式改变电荷的粒子偏离了环的主轨道，因此很容易检测到它们。这种电荷变换束包含了许多关于电子束和离子束的重要信息。另一方面，电子冷却区是质量较好的离子与相对速度从零到较大值的电子相互作用的区域。在这个意义上，冷却电子可以被视为一个纯粹的高密度电子靶。离子-电子相互作用是原子物理研究的一个重要分支，利用这些装置可以研究离子-电子相互作用。 ...更多信息 H^+离子束的电子俘获过程在实验和理论上都是众所周知的。利用这一事实，我们通过观察电子俘获产生的中性氢原子来研究电子冷却过程。从俘获率，我们可以推断出电子温度为0.2 eV。另一方面，从中性束剖面的测量中，发现循环冷却束的发射度为1-2 π mmmrad。此外，对于聚束，通过测量中性原子到达探测器的时间分布来估计聚束宽度。宽度为几十纳秒，与初始宽度几百纳秒形成对比。2)用于H_2 ^+离子的电子俘获研究。观察到一对氢原子，它们来自解离复合过程H_2 ^++ e-H +H。通过详细的分析，估算了电子束与离子束的交叉角。3)在对^3He ^+离子电子俘获的研究中，首次观察到了双电子复合过程。在捕获一个铁电子的同时，^3He ^+中已经附着的电子也从1 s态激发到2 p态。结果与理论预测一致。将来，我们希望将这些研究扩展到更重的离子。少