Elemental mapping using proton-induced x-rays

The use of particle-induced x-ray emission (PIXE) in conjunction with a sca nning nuclear microprobe (SNM) offers one of the few microanalytical techni ques capable of studies of elemental concentrations at the ppm level, with a spatial resolution of the order of 1 mum. Beam scanning capabilities and advanced data treatment make it a technique of choice for quantitative two- dimensional studies of elemental distribution. Although the ultimate aim is to obtain true quantitative elemental maps, free of concentration or thick ness artifacts, some compromises are necessary owing to experimental and co mputational restrictions. Some approaches currently used are discussed with emphasis on true elemental imaging using the dynamic analysis method. Exam ples of applications in geology and biology are shown to illustrate its ben efits and limitations. Copyright (C) 2001 John Wiley & Sons, Ltd.