Ion Beam-Induced Luminescence

James R. Huddle

US Naval Academy

Friday, February 9, 2007; VWF 104; 3:00 p.m.

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 2-3 MeV protons, and have collected spectra over the wavelength range 300 – 1000 nm. In this paper, we compare IBIL spectra to photon-induced spectra for YAG and alexandrite. We find that the IBIL spectra contain emission lines not present in the photon-induced spectra. We suspect this is because the selection rules for proton-induced excitations are less stringent than for photon-induced excitations. 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.