Quantitative Electron Microprobe Analysis

The Electron licroprobe X-!{ay Analyscr conceivcd b~ R C.\SL\I:\G and A. Cl!:\ lEI( in 1949 has been developcd as an extremelv po\\crful tool in spcctrochcmical analysis for a wide range of applications ranging from qualitative elcmcntary distribution studies to highly localiscd quantitatin analysis on a one micron scale. \\ith the increasing number oi versatile instruments commcrcially available the domain of applications - in metallurgy solid state physics mineralogy and geology biology and medicine arts and archeology - is rapidly expanding particularly because reliable quantitative analyses can be achieved. It is well established that in multicomponent specimens the relative x-ray intensity generated by the electron bombardment - i.e. the intensity ratio of the characteristic x-ray radiation emitted under identical experimental conditions by the specimen and a calibration standard - is not directly correlated to the elementary mass concentration. The use of a wide scale of carefully prepared homogeneous calibration standards is generally very tedious and restricted to binar) systems. For more complex specimens the conversion of recorded x-ra) intensity ratios to elementary mass concentration requires besides carefule selection of experimental conditions an adequate correction calculation to take account oi the various physical phenomenas occurring in the tarp;et - electron retardation electron backseattering x-ray excitation efficieney fluorescence enhaneement by eharaeteristic and continuous radiation and x-ray mass absorption.