The polarization of characteristic X radiation excited by electron impact

Abstract

Using hydrogenic wavefunctions the cross sections for ionization of an atom from the magnetic substates of the L3 level are calculated in (i) the Bethe approximation, and (ii) the first Born approximation. Calculation (ii) differs from previous work of a similar nature in that it takes as axis of quantization, the direction of the incident electron beam. Hence the polarization of the resulting characteristic X radiation is estimated; it is found to be small in comparison with the degree of polarization which typically results from the excitation of optical lines, in marked disagreement with a previous calculation.