Ion beam-induced luminescence

Abstract

Ion beam-induced luminescence (IBIL) is a technique for materials analysis. An ion beam is used to excite atoms in a target, and visible light emitted from the target material is analyzed with a fiber-optic spectrometer. Since visible light results from outer-shell transitions, IBIL can give information about the nature of chemical bonds in materials, which methods such as PIXE and RBS cannot. We have bombarded various materials, not all of which are transparent, with 2–3MeV protons, and have collected spectra over the wavelength range of 300–1000nm. In this paper, we compare IBIL and photon-induced spectra for YAG. We find that the IBIL spectra contain emission lines not present in the photon-induced spectra. We suspect that this is because the selection rules for proton-induced excitation are less stringent than for photon-induced. If this is true, then (1) IBIL may be an inherently more powerful analytical technique than photon-induced spectroscopic methods and (2) some of the states created by ion bombardment may be metastable, so that IBIL might lead to a new laser pumping scheme.