Signature of Individual Fission Products in a Nuclear Reactor Antineutrino Spectrum

Nuclear reactors are copious sources of electron antineutrinos, produced by the beta-minus decay of more than 800 neutron-rich fission fragments.  In the present work, a novel yet simple numerical procedure to analyze the antineutrino and electron spectra has been developed.  When applied to the Daya Bay antineutrino spectrum, we identify the presence of 4 nuclides, ⁹⁵Y, ^98,102Nb and ¹⁰²Tc.  Additionally, the presence of ⁹⁶Y and ⁹²Rb is revealed when the procedure is applied to the ²³⁵U electron spectrum.   The reason behind this ability to identify individual products is that the emission of antineutrinos in a nuclear reactor is not a purely statistical process.   Out of the 800 fission products, a smaller number will be significantly produced due to shell effects, and for each one of those fission products, the number of strong beta transitions is reduced to just a few.  Another recent development in the summation method that will be presented is the generation of cumulative fission yield covariances, which allows for uncertainty quantification on the antineutrino yield and related quantities.