Neutron in-beam Mössbauer spectroscopy employing the 56Fe( \(\text{n}, \gamma\) )57Fe* reaction, which had been suspended after the Great East Japan Earthquake in 2011, was resumed following the restart of research reactors of JRR-3 in Tokai, Japan. In-beam Mössbauer spectra following neutron capture for 57Fe were recorded for stainless-steel and high-purity \(\alpha\) -iron foils. Concurrently, the elemental composition of the stainless-steel sample was quantified by prompt \(\gamma\) -ray neutron activation analysis (PGNAA). The resonance absorption rate of the 14 keV \(\gamma\) -rays emitted after neutron capture was calculated, and the peak-to-background ratio of the measured Mössbauer spectra was evaluated to assess spectral quality.