Light detection with spectral analysis at the Legnaro nuclear microprobe: Applications in material and earth sciences

Among the numerous ion beam analytical (IBA) techniques available for mater ial characterisation, ionoluminescence (IL) has not attracted the interest that it should deserve. Although the importance of IL technique, particular ly if combined with other IBA techniques, has been widely proven, very few apparatuses to analyse light emission spectra have been installed at the mi crobeam facilities. In this paper we present the new IL apparatus installed at the Legnaro (LNL) Ion Microbeam Facility. The system is a modification of the OXFORD MONOCL2 apparatus for cathodoluminescence. Light collection i s performed by using a retractable parabolic mirror located at a very short distance from the sample, with a small aperture to allow the ion beam to h it the sample. Accurate positioning of the retractable mirror directly coup led to a chamber mounted high-resolution monochromator allows for high ligh t collection efficiency. This design assures that IL can be used with low b eam currents (<1 pA) with the consequent reduction of the radiation damage, which often occurs during ionoluminescence measurements. A summary of soni c meaningful results obtained with such an apparatus is presented. The comb ination of IL/PIXE was used to characterise natural silica glass, known as Libyan Desert Glass, and cubic BN grains; polycristalline CVD diamond has b een studied by a synergetic combination of IBICC/IL technique. (C) 2001 Els evier Science B.V. All rights reserved.