Differential cross section measurements at 10 eV region for one-electron caputure processes concerning multiply-charged ion collisions.

用来测量电荷转移反应产生的散射离子角分布的交叉束装置的性能有了很大提高。它由一个小型电子束离子源、一个双静电半球能量选择器和一个离子探测器组成。为了获得良好的能量分辨率和角分辨率，采用超音速喷嘴波束来制备靶材。碰撞能测定的精度优于0.1 eV，角度读数的精度约为0.5度。用2KV的引出电位引出离子，然后减速到250×Q eV，其中Q表示离子的电荷态，然后用Wien滤光片进行质量选择。选择质量的离子被减速到选择器的传输能量，约为30xq eV，然后使用两套三元透镜再次减速到所需的碰撞能量。在半高宽下，初级光束的角发散约为*0.5度，能量扩散估计为0.3xq eV。在10 eV处的束流强度约为pA。为了分析产物离子的能量，使用了90度静电圆柱形偏转器，并在其上安装了位置灵敏探测系统。在本研究过程中，我们注意到最重要的一点就是噪声的消除。在实验室框架下，在ECM=10 eV，0~5度范围内，测量了0^&lt；2&gt；He碰撞单电子俘获过程中产生的0^&lt；2&gt；离子的动能。在能谱上只观察到一个单峰。这个峰对应于反应，0^&lt；2&gt；(^3P)He-&gt；0^(^2P)H^e 5.6 eV；这与以前报道的结果很好地一致，证明了该装置的性能足以在一个未知的能区进行测量。

The performance of the crossed-beam apparatus to measure the angular distribution of the scattered ions created by charge-transfer reactions was improved much. It consists of a small Electron-Beam-Ion-Source, a double electrostatic hemispherical energy-selector, and an ion detector. To obtain good energy- and angular-resolution, a supersonic nozzle-beam is used to prepare the target. The accuracy of the collision-energy detennination was found to be better than 0.1 eV, and that of angular -reading was about 0.5 degree. The ions were extracted from the source by the extraction potential of 2 kV, then decelerated to 250 x q eV, where q denote the charge-state of the ions, then mass-selected by a Wien-filter. The mass-selected ions were decelerated to the transmission energy of the selector, about 30 xq eV, then again decelerated to the desired collision energy using two sets of three-element lens.The angular divergence of the primary beam was about*0.5 degree , and the energy spread was estimated to be 0.3 x q eV, at FWHM.The intensity of the beam was in the order of pA at 10 eV.For the energy analysis of the product ions, a 90 degree electrostatic cylindrical deflector was used, and a position-sensitive detector system is attached to that. During the course of this study, it is noticed that the most important point is the noise redaction. Therefore, the analyzer system is located inside well shielded-box.The kinetic energy of 0^<2+> ions produced in one-electron capture process in 0^<2+> + He collisions were measured at Ecm = 10 eV, from 0 to 5 degree in the laboratory frame. Only a single peak was observed on the energy spectrum. This peak corresponds to the reaction, 0^<2+>(^3P) + He ---> 0^+(^2P) + H^e + 5.6 eV ; this agrees well with that reported previously, and proved that the performance of the apparatus is good enough to do measurement in an unexplored energy region.