Analysis of laser-ablated solid samples using a small time of flight mass spectrometer

The design and use of a small time of flight (TOF) mass spectrometer for producing mass spectra of ions which have been laser ablated from a solid metal target are described. TOF spectra with a resolution m/ Delta m of 100 were produced. Known samples of inconel were used to characterize the operation of the spectrometer. Isotope separation was demonstrated and mass spectra, in which the ratios of constituents were representative of the composition of the sample, were produced. The beneficial effect of a stainless steel grid placed between the target and flight tube at a positive potential was investigated. Results are shown and correlated with theoretical flight times for different conditions. A model is proposed for the various processes occurring.