Electron cleaning: ultra-high cleanliness without UHV

Contamination in electron microscopy is a persistent problem. Depending on the kind and amount of precursor molecules, vacuum level, sample material and temperature, and the intensity and energy of the irradiating electrons, deposition can overwhelm removal, or vice versa. Electron irradiation with 100 eV electrons is a new method for achieving ultra-high cleanliness (UHC), so the sample can be irradiated by electrons indefinitely without depositing any perceptible amount of contamination. The simple and effective, high-vacuum cleaning method creates new possibilities in many electron- and ion-based measurements where UHC is needed, but ultra-high vacuum is not necessarily required.