Experimental investigation of the angular distribution of characteristic X-radiation following electron impact ionisation

There are a number of theoretical predictions that the characteristic X-radiation following electron impact ionisation is partially polarised and has a non-isotropic angular distribution. The angular distributions of L and K radiation of selenium following electron impact ionisation at bombarding energies of 600 and 300 keV, and that of the M, L_l, L_alpha , L_beta , L_gamma radiations of bismuth at bombarding energies of 100 and 300 keV have been measured. Within experimental error these radiations were found to be isotropic.