Detection of low-energy electrons with transition-edge sensors

We present the detection of electrons with kinetic energy in the 100 eV range with transition-edge sensors (TESs). This has been achieved with a (100 × 100)-μm2 Ti/Au bilayer TES, with a critical temperature of about 84 mK. The electrons are produced directly in the cryostat by an innovative cold 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 (90–101) eV energy range, which is found to be compatible with the resolution of this same device for photons in the same energy range. This work opens possibilities for high-precision energy measurements of low-energy electrons.