Wu Bin, Xia Lei, Li Hong-Kai, Zeng Xian-Jin, Tian Shan Xi
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, China.
Rev Sci Instrum. 2012 Jan;83(1):013108. doi: 10.1063/1.3678328.
In molecular dissociative ionization by electron collisions and dissociative electron attachment to molecule, the respective positively and negatively charged fragments are the important products. A compact ion velocity mapping apparatus is developed for the angular distribution measurements of the positive or negative fragments produced in the electron-molecule reactions. This apparatus consists of a pulsed electron gun, a set of ion velocity mapping optic lenses, a two-dimensional position detector including two pieces of micro-channel plates, and a phosphor screen, and a charge-coupled-device camera for data acquisition. The positive and negative ion detections can be simply realized by changing the voltage polarity of ion optics and detector. Velocity sliced images can be directly recorded using a narrow voltage pulse applied on the rear micro-channel plate. The efficient performance of this system is evaluated by measuring the angular distribution of O(-) from the electron attachments to NO at 7.3 and 8.3 eV and O(+) from the electron collision with CO at 40.0 eV.
在通过电子碰撞进行的分子离解电离以及分子的离解电子附着过程中，分别带正电和负电的碎片是重要产物。开发了一种紧凑的离子速度成像装置，用于测量电子 - 分子反应中产生的正、负碎片的角分布。该装置由一个脉冲电子枪、一组离子速度成像光学透镜、一个包括两块微通道板的二维位置探测器、一个荧光屏以及一个用于数据采集的电荷耦合器件相机组成。通过改变离子光学器件和探测器的电压极性，可以简单地实现正离子和负离子的检测。使用施加在后部微通道板上的窄电压脉冲可以直接记录速度切片图像。通过测量7.3和8.3电子伏特下电子与NO附着产生的O(-)以及40.0电子伏特下电子与CO碰撞产生的O(+)的角分布，评估了该系统的高效性能。
