  The ACCESS (Array of Cryogenic Calorimeters to Evaluate Spectral Shapes)
project aims to establish a novel technique to perform precision measurements
of forbidden \b{eta}-decays, which can serve as an important benchmark for
nuclear physics calculations and represent a significant background in
astroparticle physics experiments. ACCESS will operate a pilot array of
cryogenic calorimeters based on natural and doped crystals containing
\b{eta}-emitting radionuclides. In this way, natural (e.g. 113 Cd and 115In)
and synthetic isotopes (e.g. 99Tc) will be simultaneously measured with a
common experimental technique. The array will also include further crystals
optimised to disentangle the different background sources, thus reducing the
systematic uncertainty. In this paper, we give an overview of the ACCESS
research program, discussing a detector design study and promising results of
115In.
