Laser Used for Mass Analysis

Abstract

The focused beam from a `giant pulse' laser has been used to vaporize and ionize thin samples of solid material and so provide the ion source of a time of flight mass spectrometer. Ions produced in this way have an energy spread of 0–500 V and this has necessitated employing an energy filter to obtain a resolution of about 30. Samples of 10⁻⁹ g from metal foils have been successfully analyzed and have shown comparable ionization efficiencies for a large number of metals. When this technique was applied to the analysis of crystals of organic compounds only atomic ions were observed and although the ionization efficiency of the metal atoms is again comparable, the efficiency of the other components depends critically on the power of the laser beam.