The shape of the electron spectrum emitted in β decay carries a wealth of information about nuclear structure and fundamental physics. In spite of that, few dedicated measurements have been made of β-spectrum shapes. In this work we present a newly developed detector for β electrons based on a telescope concept. A thick plastic scintillator is employed in coincidence with a thin silicon detector. The first measurements employing this detector have been carried out with mono-energetic electrons from the high-energy resolution electron-beam spectrometer at Bordeaux. Here we report on the good reproduction of the experimental spectra of mono-energetic electrons using Monte Carlo simulations. This is a crucial step for future experiments, where a detailed Monte Carlo characterization of the detector is needed to determine the shape of the β-electron spectra by deconvolution of the measured spectra with the response function of the detector. A chamber to contain two telescope assemblies has been designed for future β-decay experiments at the Ion Guide Isotope Separator On-Line facility in Jyv\"askyl\"a, aimed at improving our understanding of reactor antineutrino spectra.
@article{arxiv.2305.13832,
title = {First measurements with a new $\beta$-electron detector for spectral shape studies},
author = {V. Guadilla and A. Algora and M. Estienne and M. Fallot and W. Gelletly and A. Porta and L. -M. Rigalleau and J. -S. Stutzmann},
journal= {arXiv preprint arXiv:2305.13832},
year = {2024}
}