Diseño y mediciones con una fuente de iones del tipo de arco colimado en campo magnético II

Abstract

The definite construction of the ion source is described-There have been made further investigations of the properties of the source improving specially the extracting and focussing of the ion beam, which allowed to measure practically 100 % of the extracted ions on the collectin electrode, even at the maximun current of 40 mA. It seems evident that the limiting factor on the maximun current is not due to the sourde itself, but rather due to space charge effects in the extracted beam, which latter tend to deteriórate the focussing and give rise to secondary emission. High energy secondary electrons which find the way back through the source, produce local heating of the filament and instabilities of the are current. A magnetic analysis of the ion beam shows a maximun percentage of protons of 30 % related to the total hydrogen—ion current. Humidity of the input hydrogen gives rise to a strong oxygen peak.