Energy dependent angular distribution of individual $\gamma$-rays in the ${}^{139}$La($n$, $\gamma$)${}^{140}$La* reaction

Abstract

Neutron energy-dependent angular distributions were observed for individual $\gamma$-rays from the 0.74 eV p-wave resonance of ${}^{139}$La+$n$ to several lower excited states of ${}^{140}$La. The $\gamma$-ray signals were analyzed in a two dimensional histogram of the $\gamma$-ray energy, measured with distributed germanium detectors, and neutron energy, determined with the time-of-flight of pulsed neutrons, to identify the neutron energy dependence of the angular distribution for each individual $\gamma$-rays. The angular distribution was also found for a photopeak accompanied with a faint p-wave resonance component in the neutron energy spectrum. Our results can be interpreted as interference between s- and p-wave amplitudes which may be used to study discrete symmetries of fundamental interactions.

arXiv comment6 pages, 7 figures

References in corpus (4)

• Angular Distribution of $\gamma$-rays from Neutron-Induced Compound States of ${}^{140}$La
• The 139La(n,gamma) cross section: key for the onset of the s process
• Transverse asymmetry of $\gamma$ rays from neutron-induced compound states of ${}^{140}\mathrm{La}$
• Characterization of Germanium Detectors for the Measurement of the Angular Distribution of Prompt gamma-rays at the ANNRI in the MLF of the J-PARC

Cited by in corpus (4)

• Measurement of the transverse asymmetry of $\gamma$-rays in the ${}^{117}$Sn(n,$\gamma$)${}^{118}$Sn reaction
• Angular distribution of $\gamma$ rays from the p-wave resonance of ${}^{118}$Sn
• Angular distribution of $\gamma$-rays from a neutron-induced $p$-wave resonance of ${}^{132}$Xe
• Measurements of neutron total and capture cross sections of ${}^{139}$La and evaluation of resonance parameters