Development of a new and high-efficiency negative ion source of electron-stimulated desorption type

一个简单而小的离子源（-1 cm^3）被开发出来，即使是那些电子亲和度小于-1 eV的元素也能产生负离子。将粉状样品（- 10mg）沉积在纱布（G, -0.1 cm^2）上，用灯丝(F)发出的电子（高达-3 mA和-300 eV）轰击。从G中解附出来的离子很容易被提取出来，因为F被固定在G的下面。H^-、D^-、Li^-、Cl^-、Na^-、F^-和Ag^-等离子很容易从碱化物和卤化物等各种样品中产生。例如，NaH ^-的总离子电流、密度和离子产率（离子与电子电流比）分别高达-0.1 mA、-1 mA cm^<-2>和-1%，尽管加热F的电功率仅为-5 W。同样，氢离子也很容易产生。H_2的引入对H^<(] SY.+-.[)>的产率影响不大。

A simple and small ion source (-1 cm^3) was developed to produce negative ions of even those elements having electron affinity less than -1 eV.A powdery sample (-10 mg) deposited on a gauze (G, -0.1 cm^2) was bombarded with electrons (up to -3 mA and -300 eV) emitted from a filament (F). The ions desorbed from G were easily extracted because F was mounted beneath G.Those ions of H^-, D^-, Li^-, Cl^-, Na^-, F^- and Ag^- were readily produced from various samples such as alkali hydrides and halides. The total ion current, its density and the ion yield (ion to electron current ratio) of H^- from NaH, for example, were as large as -0.1 mA, -1 mA cm^<-2> and -1%, respectively, although the electric power to heat F was only -5 W.Similarly, H^+ was readily produced. Introduction of H_2 had little effect upon the yield of H^<(〕SY.+-.〔)>.