适用于高分辨率分子束实验的离子源

The Special ionizer Design for Using in High Resolution Molecular Beam Experiment

分子束实验在微观动力学的研究中占有重要的位置。在这种实验中,进入探测器的产物往往比探测器中的本底还要低好几个数量级。因此除了采用高强度的超声分子束源,分子束的调制,离子、电子倍增器,分级排气探测器及计数技术等手段来提高信噪比外,改进离子源的本身也是一项很重要的工作。另外,为了能精确测得产物的飞行速度以分析反应过程中的能量分配,还要求离子源具有高的分辨率。本文叙述了一种新设计的高分辨率离子源。实验结果表明,新型离子源的分辨率和灵敏度均优于Brink型离子源。

Molecular beam experiment plays an important role in molecular reaction dynamics. In molecular beam experiment the density of the scatteredproducts is at best the same order of magnitude as the density of the backgr-ound in tne detector chamber, and typically is several orders of magnitudeless. Apart from the use of modern high intensity supersonic beam source, beammodulation, ion-electron multipliers, differential pumping of the detectorand counting techniques to increase the ratio of signal to noise of the detect-or, the improvement of the ionizer itself is also an interesting project. Besi-des, the time of flight of the products is one of the main parameters in theinvestigation of energy distribution during the reaction. thetefore the resoluti-on of the ionizer should be as higk as possible in order to measure the timeof flight accuratelly. A new design of high resolution ionizer is described. Ac-cording to the experimental results, the sensitivity and the resolution of thenew ionizer is Ligher tan that of the Brink's ionizer.