Depth profiling of light elements using a nuclear microprobe

In this paper, we present some examples of depth profiling of light element s with a nuclear microprobe performed at LARN during the last decade. Some new possibilities of ion beam microanalysis of light elements with our 2 MV Tandetron accelerator are also discussed. The first example of application consists of depth profiling of nitrogen an d aluminium on a SiAl alloy implanted with nitrogen. The nuclear microprobe was used to determine three-dimensional distribution of aluminium, silicon and nitrogen in a specific grain of the implanted alloy. The nitrogen dept h profile was measured using the well known N-15(p,alpha gamma)C-12 nuclear resonant reaction at 429 keV. The aluminium depth profile was measured wit h the resonant nuclear reaction Al-27(p,gamma)Si-28 at 991.8 keV. Depth profiling of carbon and oxygen is also possible using nuclear reactio ns induced by He-3 particles. Nuclear reactions like C-12(He-3,p(i))N-14 (i = 0, 1,2) or O-16(He-3,alpha(0))O-15 were used to measure local wear track s on a diamond coating after a fretting test against a Cr steel ball. PIXE microprobe and nuclear reactions induced by deuterons were also used t o characterise the gold-silicon ahoy formed by the diffusion elf silicon in to gold foils. The nuclear reaction Si-28(d,p)Si-29 in a transmission geome try was used in order to depth profile silicon especially in the grain boun daries of the gold-silicon ahoy. Some new perspectives of depth profiling light elements are also presented using our new 2 MV Tandetron accelerator, such as high energy He-4 microbea ms for depth profiling of carbon or nitrogen. (C) 1999 Elsevier Science B.V . All rights reserved.