  The CNO cycle is one of the fundamental processes of hydrogen burning in
stars. The first reaction of the cycle is the radiative proton capture on 12C
and the rate of this 12C(p,gamma)13N reaction is related to the 12C/13C ratio
observed e.g. in the Solar System. The low-energy cross section of this
reaction was measured several times in the past, however, the experimental data
are scarce in a wide energy range especially around the resonance at 1.7 MeV.
In the present work the 12C(p,gamma)13N cross section was measured between 300
and 1900 keV using the activation method. This method was only used several
decades ago in the low-energy region. As the activation method provides the
total cross section and has uncertainties different from those of the in-beam
gamma-spectroscopy technique, the present results provide a largely independent
data set for future low-energy extrapolations and thus for astrophysical
reaction rate calculations.
