Mass-energy analysis of ion plasma species at vacuum discharges with liquid Ga-In cathode

The paper presents new results on charge state and energy distributions of heavy species of plasma generated at vacuum discharges. Using a liquid metal Ga-In cathode, a self-breakdown initiation of discharge was achieved at a relatively low voltages (down to 5 kV), high pulse repetition rate (up to ~1 kHz), low discharge current (~10 A), and wide range of pulse durations (10 ns to 10 mus). By means of the HIDEN EQP analyzer system, energy spectra analysis of separate ion charge state species was performed. The data obtained show the evolution of both the ion charge states and energy distributions with changing the pulse duration from nanosecond to microsecond time scale, demonstrating the difference between the spark and steady-state arc discharge modes. Questions of optimization of analyzer voltages are discussed also for adequate extraction of different mass-to-charge and energy-to-charge ions.