A physical approach to the radiation damage mechanisms induced by X‐rays in X‐ray microscopy and related techniques

A physical approach is used to analyse the various mechanisms induced by the absorption of X‐ray photons of energies in the 0.2–20 keV range. At the atomic scale, besides the (Auger and photo) electron transport in the bulk or the ejection into the surrounding media, special attention is devoted to the specific consequences of the initial Auger decay mechanism. At the macroscopic scale, the decisive role of the poor electronic conductivity of the radiation‐sensitive materials is outlined and it is shown that the damaging effects occur in irradiated insulators because the lack of conduction electrons prevents the initial charge of the excited atoms being quickly restored. Correlating irradiation conditions and physical properties of the specimen, various expressions are proposed for the first time to quantify these effects. Some are neither dose‐ nor dose‐rate‐dependent and the influence of the surrounding medium is also considered. The fundamental mechanisms investigated here hold for a wide variety of specimens or components investigated in X‐ray microscopy. Their consequences can be easily transposed to other techniques using transmitted X‐rays.