Direct detection of Tritium and Carbon-14 beta particles with GaAs photodiodes

New measurements are reported which show beta particles emitted from 3H and 14C sources being directly detected with GaAs mesa photodiodes without use of scintillators. Spectra accumulated with GaAs diodes which were originally developed for X-ray spectroscopy are presented which show that individual beta particles from these sources can be counted and the energy they deposit in the detector measured. Potential longer term applications of this technology as it is developed further and improved include space missions, autoradiography, monitoring tritium produced by fusion reactors and nuclear decommissioning. © 2012 IOP Publishing Ltd and Sissa Medialab srl.