Detection of Low-Energy Electrons with Transition-Edge Sensors

We present the first detection of electrons with kinetic energy in the 100 eV range with transition-edge sensors (TESs). This has been achieved with a (100 x 100) μm^2 Ti-Au bilayer TES, with a critical temperature of about 84 mK. The electrons are produced directly in the cryostat by a cold-cathode source based on field emission from vertically-aligned multiwall carbon nanotubes. We obtain a Gaussian energy resolution between 0.8 and 1.8 eV for fully-absorbed electrons in the (95-105) eV energy range, which is found to be compatible with the resolution of this same device for photons in the same energy range. This measurement opens new possibilities in the field of electron detection.