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Methods
D-NRA - Nuclear Reaction Analysis using a deuteron beam
The light elements lithium, carbon, nitrogen and oxygen are of low atomic number and can be detected with a high sensitivity by D-NRA. Usually, a 1 MeV deuteron ion beam is used to irradiate the samples to induce nuclear reactions of the deuterons with the sample atoms, producing protons and alpha particles. The energies of this particles are characteristic of the element specific nuclear reaction and hence of the elements contained in the sample material. In order to determine the whole stoichiometry of a sample, this method is usually combined with RBS for the detection of the heavier sample elements.
Typical D-NRA parameters, pros and cons:
- gives the content for light elements: Li, C, N, O
- gives the absolute number of atoms- absolute: no standard is necessary
- depth: up to several µm
- measuring time per sample: 3-15 min
- lateral resolution ≥ 500 µm
- no heavy elements detectable => normally combined with RBS
- no information on the depth => higher uncertainty for depth gradients
- substrates containing C, N or O are not suitable (SiO2, graphite, …)