Diagnostics of target-cavity confined plasmas produced by nanosecond pulsed laser ablation of graphite

Ion energy of laser plasmas produced by repeated nanosecond pulsed laser ablation of graphite is measured by time-of-flight (TOF) spectrometry and retarding potential analysis. An Nd:YAG laser with lambda = 1064 nm wavelength is incident toward the center of a cylindrical graphite target while the target is rotated along its axis. Ion energy distributions are measured via TOF spectroscopy. TOF signals show a decrease in the ion peak current by half followed by shifting of the signals by 4 mu s toward later times after 10 000 laser shots. An ion energy decrease of 200 eV was measured from the retarding potential analysis. Published under an exclusive license by the AVS.