Direct Observation of Resonantp-Wave Neutron Capture

Abstract

The capture $\gamma$-ray spectra of resonances in ${\mathrm{Mo}}^{95}$ below 700 eV have been studied in an effort to make unambiguous identification of individual resonances resulting from capture of $p$-wave neutrons. A discussion is presented of the features of the experimental spectra which can be used to identify the parity of the compound state formed by neutron capture. In particular, a resonance in ${\mathrm{Mo}}^{95}$ at 107 eV with an anomalously strong ground-state transition is observed. The strength of this line is inconsistent with $s$-wave capture. The resonance must be due to capture of a $p$-wave neutron; the transition must be $E1\mathrm{}$; and the capture state must be $1^{-}$.