Cluster-ions emission from a contaminated laser-plasma target

The influence of target surface contamination on the ion spectra of laser produced plasma has been studied using time of flight mass spectrometry. It has been found that ion spectra from contaminated surface of gold and lead target essentially consists of ions of light elements impurities such as hydrogen, carbon, nitrogen and oxygen, and their associated cluster ions in addition to the ions of under laying target materials. Mass spectrometric analysis of micro plasma revealed that singly ionized cluster ions of target impurity were observed from the contaminated target surface. A model for cluster ion formation mechanisms is also proposed for the present experimental work. (author)