Antineutrino Spectra and Decay Heat Measurements with the Modular Total Absorption Spectrometer

Nuclear reactors are the largest man-made source of $\bar{\nu}}$s and as such they are excellent sources to directly measure $\bar{\nu}}$s. The predicted $\bar{\nu}}$ flux from nuclear reactors is not precisely known. One way to predict the $\bar{\nu}}$ flux, the summation method, requires precise knowledge of the $\beta$ decays of the many fission products. Because all reactor antineutrinos are created from $\beta$-decaying fission products it is imperative to experimentally measure these $\beta$ decays. In addition to producing a precise prediction of the $\bar{\nu}}$ flux, a proper understanding of the $\beta$ decay of fission products produced in nuclear reactors is important in order to understand how the decay heat energy is shared between $\gamma$ rays, $\beta$ rays, neutrons, and $\bar{\nu}}$s. The improved $\beta$ decay information influences reactor safety, and the decay back to stability of the r process. In this talk we present an overview of the latest results from the Modular Total Absorption Spectrometer Collaboration and its impact on the predicted $\bar{\nu}}$ flux from nuclear reactors.