Stopping power effects in the determination of14N by a resonance reaction

The applicability of the¹⁴N(p,p’ γ₁)¹⁴N nuclear reaction in the determination of the absolute abundance of¹⁴N, with a 2% uncertainty, was demonstrated at 4.3 MeV bombarding energy. The fact that almost all of the thick target γ-ray yield resulted from a resonance at Ep=4.0 MeV allowed to consider the necessary stopping-power corrections only at the energy of that resonance. Alternatively, the method was used to obtain the stopping power of 4.0 MeV protons in complex biological materials. Supported in part by the International Atomic Energy Agency, Vienna, Austria.