Highly Charged Metal Ions in Plasma of High-Current Short-Pulse Vacuum Arc

Highly charged beams of metal ions find many applications both in fundamental research in nuclear and atomic physics and in solving applied problems such as surface modification with ions. Now, the most effective and easy-to-implement method for producing metal ions of high charge states is the use of a high-current vacuum arc discharge of short duration. This paper presents experimental results on the generation of multiply charged metal ions based on vacuum arc plasma with a level current amplitude of about 3 kA and a level pulse duration of about 0.9 µs (full width at half maximum). Several cathode materials were investigated, such as silver, tin, lanthanum, gadolinium, and lead with atomic masses from 107.9 Da for silver to 207.2 Da for led. Also, these materials have a wide range of physical properties, such as atomic mass, melting point, heat capacity and thermal conductivity, etc. It was shown that with the specified parameters of the vacuum arc pulse, the maximum charge states for all studied materials are 11+, while the average charge is different and ranges from 7.8+ for tin to 9.6+ lanthanum. The degree of increase in the charge states of various materials is discussed.