Reservoir for ion source, esp for ionic propulsion unit in space - where reservoir has coating ensuring the smooth extn of ion stream through extn electrode

摘要

The reservoir is a metal box, the interior of which contains an ionisable molten metal or alloy. The box has a nose forming a capillary outlet slot for the melt. The internal surface of the box and slot are coated with a material (b) not wet by the melt. Materil(a) is pref. In; Pt; Pd; or Ni; whereas material(b) is pref. Zr or a Zr cpd., esp. ZrN, and may cover the entire exterior of the box. The box is pref. made in two parts, which are polished, cleaned and degreased; and then coated by vapour deposition or sputtering. The interior of the box is wet by the ionisable molten metal, but the latter does not migrate onto the box nose, so reliable operation of the ion source is achieved.