Molten salt ion source using glass capillaries as emitter

TL;DR

This paper introduces a novel molten salt ion source using glass capillaries as emitters, capable of emitting stable ion beams in both polarities, with potential applications in ion beam technology.

Contribution

It presents a new ion source design employing glass capillaries for field evaporation of molten salt ions, differing from traditional liquid metal ion sources.

Findings

Stable ion emission for about 50 minutes

Ion beam intensity reaches several microamperes

Formation of a salt bubble in the capillary tip observed

Abstract

A proof of concept of an ion source using a molten salt mixture rich in Cs and O ions, able to emit an ion current both in positive and negative polarities, is presented. Similar to liquid metal ion sources, the ions of the salt are emitted by field evaporation from a Taylor cone formed under the influence of an intense electric field. In contrast to an "open" source design in which the conducting liquid covers the surface of a metallic needle, the presented setup uses a conical glass capillary as an emitter tip. {\ffcol The latter is observed by a camera, which revealed the formation of a bubble in the tip containing the molten salt. A glow was also observed during beam emission revealing the anchoring point of the stressed meniscus.} A stable ion beam emission of about 50 min and an intensity of several $\mu$A was obtained. The behavior of the molten salt mixture in vacuum conditions is discussed, as its properties are essential to the design of the presented ion source.