Study of beta spectrum shapes relevant to the prediction of reactor antineutrino spectra

TL;DR

This study measures the beta spectra of key isotopes 92Rb and 142Cs to improve the accuracy of reactor antineutrino spectrum predictions, validating models with new experimental data.

Contribution

It introduces a new experimental setup for precise beta spectrum measurements of reactor-relevant isotopes, enhancing the reliability of antineutrino spectrum models.

Findings

Beta spectra of 92Rb and 142Cs were successfully measured.

Experimental results agree with model predictions, validating current shape corrections.

The method can be extended to other isotopes for improved reactor antineutrino predictions.

Abstract

The shapes of the beta spectra of 92Rb and 142Cs, two of the beta decays most relevant for the prediction of the antineutrino spectrum in reactors, have been measured. A new setup composed of two dE-E telescopes has been used. High purity radioactive beams of the isotopes of interest were provided by the IGISOL facility using the JYFLTRAP double Penning trap. The resulting beta spectra have been compared with model predictions using beta decay feedings from total absorption gamma spectroscopy measurements and shape corrections employed in the calculation of the antineutrino spectrum, validating both further. The procedure can be extended to other relevant nuclei in the future, providing solid ground for the prediction of the antineutrino spectrum in reactors.