Abstract
The quality of a microanalysis by means of X-rays may be defined in terms of the degree of spatial resolution attained, the sensitivity of detection, the precision of the measurement and the accuracy of the measurement. These parameters are discussed in relation to the ultra-soft X-ray region. The ability to perform a quantitative analysis receives special attention, and is found to be greatly affected by the nature of the chemical bonding of the specimen, the correction theory used, and the availability of accurate mass-absorption coefficient data.