Simultaneous determination of 14N and 15N by elastic backscattering and nuclear reaction: application to biology
The aim of this study is to use a nuclear microprobe for simultaneous localization and quantification of 14N and 15N in plant cells. A summary of the main nuclear reactions usually used for this purpose is presented. For 15N, we tested the nuclear reaction 15N(p,αγ) 12C. The yeild curve was measured between 2.90 and 3.35 MeV; following the gamma ray at 4.439 MeV, it exhibited two resonances at 2.970 and 3.270 MeV. The choice of this energy range also made it possible to measure 14N by photon elastic backscattering. The yeild curve of the reaction 14N(p,p) 14N was measured in the same energy range. The choice of a 3 MeV proton beam energy enabled us to optimize the 15N detection limit and to have enough sensitivity for 14N determination. The stability of nitrogen under the proton beam with these analytical conditions was tested.