Analysis for 15N by proton scattering

STABLE isotopes have a great potential as tracers in the life sciences and environmental research, but their uses are still limited compared with those of radioisotopes. Radioisotopes have been widely used as trace elements, although there are problems in handling radioactive materials and preventing environmental contamination. The increasing concern about exposure to small amounts of radioactivity has caused us to consider the advantages of stable isotopes. The detection of stable isotopes, however, is not as sensitive as that for radioactive tracers and the preparation of a sample for use in stable isotope analysis is complicated. We have looked at the possibility of using a nuclear reaction caused by accelerated charged particles as a way of detecting stable isotopes. We have developed a system of stable isotope analysis using proton elastic scattering. Elastic scattering was chosen because the cross-sections are generally an order of magnitude larger than that of other reactions. Moreover, proton elastic scattering analysis has many advantages which are absolute, multi-element, rapid and subject to automatic data handling. Using this method an analysis for 15N has been done for biological studies. Nitrogen is an important component of various organic compounds which occur naturally but it has no long-lived radioactive isotopes. Here we outline the new system, and give an example of 15N analysis.