β decay of 141Ba

The beta-decay strength function of nuclides produced in fission is important as it dictates the distribution of decay energy between electrons, neutrinos, and gamma rays and so is critical for calculating decay heat in reactors and for estimating the reactor antineutrino spectrum. Several experimental techniques are available to determine this strength function, including electron spectroscopy, gamma-ray calorimetry (TAGS spectroscopy), and detailed, high-resolution spectroscopy with modern large high-purity germanium arrays. This work investigates the decay of the well-known and strongly produced fission fragment Ba-141. A beam of Cs-141 was implanted at the target position of the Gammasphere and the subsequent decay of the daughter Ba-141 was studied. Extensive decay spectroscopy was possible up to the decay Q value of 3.197(7) MeV, including a significant extension of the level scheme and detailed angular correlation measurements for all levels with greater than 0.25% beta feeding. The distribution of the beta-decay strength was then inferred and compared to previous calorimetric studies. The agreement was excellent and provides a benchmark for comparing strength function methods and data for a more detailed understanding of the structure of La-141.

Automated summary

This study investigates the decay of the fission fragment Ba-141 to understand the beta-decay strength function of nuclides produced in fission. Different experimental techniques were used, and the results were compared with previous studies, showing excellent agreement and providing a benchmark for further understanding the structure of La-141.