SOURCES OF MULTIPLY CHARGED METAL IONS: VACUUM DISCHARGE OR LASER PRODUCED PLASMA?

摘要

An analytical survey is presented of the recent researches aiming to obtain beams of the multiply charged metal ions from vacuum discharges of different types. The main attention is paid to the works, which have been performed the recent two years by the team headed by the author. It is shown that plasma jet of a moderate voltage (< 2.5 kV) vacuum spark generates short- run beams of the cathode matter ions (Cu~(n+), Ta~(n+)) with the charge states up to +19 for copper and +50 for tantalum. The mean charge states of the ions are: Z(Cu) = 9.3, Z(Ta) = 20 and current density of these ions attains 30 mA/cm~2 at a distance of 40 cm from the discharge gap. Comparison is performed of these data with the corresponding values for metal ions obtained from a laser produced plasma and it is shown that the vacuum discharge plasma as a source of the multiply charged metal ions is rather more effective than the laser one.