First measurements with a new \(\beta\)-electron detector for spectral shape studies

The shape of the electron spectrum emitted in \(\beta\) decay carries a wealth of information about nuclear structure and fundamental physics. In spite of that, few dedicated measurements have been made of \(\beta\)-spectrum shapes. In this work we present a newly developed detector for \(\beta\) 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 \(\beta\)-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 \(\beta\)-decay experiments at the Ion Guide Isotope Separator On-Line facility in Jyv\"askyl\"a, aimed at improving our understanding of reactor antineutrino spectra.