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

在电子冷却过程中，离子与电子在存储环圆周的一部分长而直的部分合并。在这种情况下，离子以一定的概率捕获冷却的电子。以这种方式改变电荷的粒子偏离了环的主轨道，因此很容易被探测到。这种电荷变化的电子束包含了许多关于电子束和离子束的重要信息。因此，可以通过对电荷变化束测量的详细分析来诊断加速器。另一方面，电子冷却部分是质量好的离子与相对速度从零到大的电子相互作用的区域。从这个意义上讲，冷却的电子可以看作是一个纯高密度的电子靶。因此，作为原子物理研究的一个重要分支，离子-电子相互作用可以用这些装置来研究。对三种离子进行了研究：1)Ele…H^+束更多的ctron俘获过程在实验上和理论上都已被熟知。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。从俘获速率，我们可以推导出电子温度为0.2 eV。另一方面，通过对中性束的测量，发现循环冷却束的发射度为1-2pi mm mrad。此外，对于聚束光束，通过测量中性原子到达探测器的时间分布来估计束团宽度。宽度为几十毫微秒，与最初几百毫微秒的宽度形成鲜明对比。2)H_2~+离子的电子俘获研究。观察到一对来自解离复合过程的氢原子H_2^++e--H+H。通过详细的分析，估算了电子束和离子束的交叉角。3)在研究^3He~+离子的电子俘获过程中，首次观察到了双电子复合过程。这是在捕获费尔电子的同时，已经在^3He^+中附着的电子也从1s态激发到2p态的过程。这一结果与理论预测一致。未来，我们希望将这些研究扩展到更重的离子。较少

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