Abstract
The multipolarity of the main transition leading to the ground state in was investigated using the angular correlations of rays. The analyzed -coincidence data were obtained from the experiment performed at Institut Laue-Langevin Grenoble at the PF1B cold-neutron facility. The EXILL (EXOGAM at the ILL) multidetector array, consisting of 16 high-purity germanium detectors, was used to detect transitions. The mixing ratio of the 320-keV ray was defined by minimizing a multivariable function constructed from the coefficients of angular correlation functions for seven pairs of strong transitions in . As a result, the almost pure multipolarity of the 320-keV ray was obtained, with an admixture of less than 0.6% only (95% confidence limit). Based on this multipolarity the neutron-capture cross section leading to the ground state in , that decays in turn to radiotoxic , was determined to be within the limits 21.3(9) and 21.5(9) mb. This result is important for nuclear reactor applications.
- Received 23 March 2016
- Revised 23 May 2016
DOI:https://doi.org/10.1103/PhysRevC.94.014311
©2016 American Physical Society