For @[email protected], this should be defined as the minimum distance of two points (areas) on the specimen corresponding to signal levels of 16 and 84%. For electron signals originating from top surface layers like @[email protected] or @[email protected] and secondary ions the lateral resolution for qualitative purposes corresponds to the @[email protected] For signals originating in a greater depth of the sample (@[email protected], X-rays) the lateral resolution is worse than the corresponding value of the beam diameter due to the @[email protected] of the @[email protected] The lateral resolution may be determined exactly with a sandwich specimen or a sharp edge specimen, or approximately with a specimen showing a regular microstructure of known dimensions. Recommended abbreviation: Lat. Res. (qualitative); unit: \(\text{m}\); range: \(\text{nm}\) or \(\unicode[Times]{x3BC} \text{m}\). For @[email protected], this should be defined as the minimum distance of two points (areas) on the specimen corresponding to signal ratios of \(10^{4}\). This condition assures that the value for the lateral resolution defines the diameter of the analytical area which yields the total analytical signal. Due to the effect of electron @[email protected] in a solid and 'tail effects' in ion beam analysis the quantitative lateral resolution is significantly larger than the beam diameter. Recommended abbreviation: Lat. Res. (quantitative); unit: \(\text{m}\); range: \(\text{nm}\) or \(\unicode[Times]{x3BC} \text{m}\).