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The recent progress in aberration-corrected optics in (scanning)transmission electron microscope ((S)TEM) provides intense electron probe, which allows an ultra-high spatial (e.g.sub-(A)) and energy (e.g.~30meV) resolutions for imaging and analysis with previously incomparable signal-to-noise ratio.In reality,however, real resolutions are limited by the effect of beam damage in many materials,especially in glassy (non-metallic) materials.Irradiation by an intense and energetic electron beam may create atomic displacement, the definition of damage, on surface and in bulk.Quantitative result obtained by exposing to such intense electron probe must be therefore interpreted with cautions.Despite its importance understanding of damage mechanism, especially in glassy materials, has not been as highly valued as it should be.In this talk, I will discuss challenges and concerns when (S)TEM techniques are applied to glassy materials.Unlike in metallic materials, damage in glassy materials is caused mainly by the induced electric field.This highly localized electric field is produced by the accumulated charges due to the excitations and ionizations by incident electrons.The distribution and strength of the induced electric field will be analyzed and discussed in detail, in both TEM and STEM illumination modes.Measured in a soda silicate glass, the maximum strength of electric field induced by a 2 nA STEM probe can reach as high as 1011 ~ 1012 V/m in the [SiO4] tetrahedral networks.Cations (glass modifiers), ranging from light alkali, e.g.Na+, to very heavy rare earth ions, e.g.Eu3+, in the [SiO4] tetrahedral network can be then displaced easily, causing beam damage and introducing artifacts in quantification analysis.By contrast, the [SiO4] network itself is apparently robust under such a strong electric field.The survival of the [SiO4] network in the electric field will be interpreted based on its local symmetry and bonding characteristics.The ultimate goal of this presentation is to find solutions to these challenges and concerns.How can we apply (S)TEM for glassy materials? A model is introduced based on the thorough investigation of damage dependence of experimental conditions and theoretical analysis.Two types of thresholds are discovered in this model.One is the threshold of current density of electron beam, below which the induced electric field is not strong enough to cause damage.The other is the threshold of exposure time for a given beam current density.The damage only occurs when the exposure is longer than this threshold.Therefore, to reduce or even eliminate beam damage in glassy materials, either a small current density or short exposure is necessary.