Speaker
Description
Transition-edge sensors (TESs) are thin superconducting films operated close to their critical temperature, and have been employed as micro-calorimeters with excellent intrinsic energy resolution in the detection of single photons. Recent works have explored their potential for the detection of single electrons. This can be a key point in rare-event
searches, ranging from neutrino experiments to dark matter investigation. The experimental setup at INRiM (Istituto Nazionale di Ricerca Metrologica), in Italy, uses a cold electron source based on field emission from vertically-aligned carbon nanotubes, coupled with bilayer gold/titanium TES devices with a critical temperature between 80 and 90 mK. It has already demonstrated the detection of single electrons in the 100 eV energy range, with an energy resolution compatible with that of photons of the same energy. In our latest results, we have improved on the experimental conditions so as to drastically reduce partially-absorbed events, and achieving a FWHM about 20 times better than in previous measurements. This represents a major milestone in the development of high- precision spectroscopy for low-energy electrons with TES devices, which can become an enabling technology also for dark matter research.