T. Uchiyama, M. Igashira and H. Kitazawa

Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology
2-12-1 O-okayama, Meguro-ku, Tokyo 152, Japan

We have observed capture gamma-ray spectra from the 46keV narrow d3/2-wave resonance and the 84keV strong p3/2-wave resonance in 24Mg. In the d-wave resonance capture, radiative decay strength concentrates mostly on the ground-state transition. In the p-wave resonance capture, distinct gamma rays were observed for the El transitions to the ground (5/2+), 585keV(1/2+), 1965keV(5/2+) and 2564keV(1/2+) states of 25Mg . The observed partial radiative widths for these transitions were compared with the values obtained from the Lane-Mughabghab optical model formula of the valence capture model. As a result, we found that the model calculations reproduce well the observed widths for the transitions from the p-wave resonance to the 1/2+ states, while for the transitions to the 5/2+ states the calculated values are about two times as large as the observed ones.

KEYWORDS: NUCLEAR REACTIONS 24Mg(n,γ), E=46, 84keV, measured σ(E,Eγ) at 125°, 25Mg deduced resonances, Γγ, Natural target