  The 14N(p,gamma)15O reaction plays a vital role in various astrophysical
scenarios. Its reaction rate must be accurately known in the present era of
high precision astrophysics. The cross section of the reaction is often
measured relative to a low energy resonance, the strength of which must
therefore be determined precisely. The activation method, based on the
measurement of 15O decay, has not been used in modern measurements of the
14N(p,gamma)15O reaction. The aim of the present work is to provide strength
data for two resonances in the 14N(p,gamma)15O reaction using the activation
method. The obtained values are largely independent from previous data measured
by in-beam gamma-spectroscopy and are free from some of their systematic
uncertainties. Solid state TiN targets were irradiated with a proton beam
provided by the Tandetron accelerator of Atomki using a cyclic activation. The
decay of the produced 15O isotopes was measured by detecting the 511 keV
positron annihilation gamma-rays. The strength of the Ep = 278 keV resonance
was measured to be 13.4 +- 0.8 meV while for the Ep = 1058 keV resonance the
strength is 442 +- 27 meV. The obtained Ep = 278 keV resonance strength is in
fair agreement with the values recommended by two recent works. On the other
hand, the Ep = 1058 keV resonance strength is about 20% higher than the
previous value. The discrepancy may be caused in part by a previously neglected
finite target thickness correction. As only the low energy resonance is used as
a normalization point for cross section measurements, the calculated
astrophysical reaction rate of the 14N(p,gamma)15O reaction and therefore the
astrophysical consequences are not changed by the present results.
