Determination of the β-decay Strength Distributions of Isotopes near ¹³²Sn using Total Absorption Spectroscopy

The β-decay properties of isotopes across the nuclear chart, such as half-lives and β-delayed neutron emission probabilities, are critical information for many areas of nuclear science from astrophysics to nuclear energy. Yet the properties of many exotic nuclei are not able to be measured with current experimental capabilities, requiring theoretical models to calculate the desired quantities. These models require validation against experimental data to ensure reliable predictions. β-decay strength distributions are useful for benchmarking β-decay models because they can be directly compared to theoretical β-decay strength values and provide a more robust test rather than comparing model outputs. Determining the β-decay strength distribution for a given initial state requires the β-feeding intensity distribution, which is often not well characterized for nuclei far from stability due to high Q_β values and fragmented decay schemes with many weak β-decay branches. This issue can be addressed via the deployment of high-efficiency detectors designed to allow for the reconstruction of the β-feeding to each level in the daughter nucleus through the summation of the energies of all γ-rays emitted following β-decay. In this work, the capabilities of the ²⁵²Cf spontaneous fission ion source (CARIBU) at Argonne National Lab were leveraged to produce ions of ¹²⁹In and ¹³⁰In. The Summing NaI (SuN) total absorption spectrometer was used to detect β-delayed γ-rays in conjunction with a plastic scintillator detector for β-particle detection. The SuNTAN movable magnetic tape station was used as an ion implantation point and a transport mechanism to remove longer lived contaminants through beam cycling. β-feeding intensities are determined using a chi-squared minimization procedure utilizing experimental and simulated data using a combination of the RAINIER and Geant4 software packages. In this work, preliminary results in determining the β-decay strength distributions for the β decays of ¹²⁹In and ¹³⁰In will be presented.