PMMA, polybutadiene and epoxy resin have been analyzed by using a FAB-SIMS. This technique enables the mass analysis of these thermolabile plastics without any trouble caused by electric charging on the sample surface. It is shown through the in-situ measurement of mass spectra of the residual gas, that neither thermal decomposition nor thermal degeneration of the samples occur through the bombardment with the fast atom primary beam.
A simulation for the electric charging on insulator surfaces has been tried with an electrically equivalent circuit for the insulators bombarded by ions and by fast atoms. The results are compared with the experimental data obtained by the deflection of a focused electron beam which passed near the charged sample surface.