Determination of the energy spectra of neutral atoms formed by expansion of a laser-irradiated target

A time-of-flight determination was made of the energy spectra of the neutral component of a laser plasma to find the amount of nonionized material in the plasma flow. It was found that under these experimental conditions, the fraction of neutral atoms formed by recombination of ions during the flight was negligible ($\lesssim$ 1 %). When the parameters of the laser pulse and a shell microsphere were matched in experiments using the Del'fin facility, this method could be used to monitor the state of the target material at the instant of maximum compression.