Lateral Space Distribution of X-ray Photoelectrons

The lateral distribution in space of the directions of emission of photoelectrons ejected from argon atoms by partially polarized x-rays having the mean wave-length 0.53A was determined by examination of photographs of 2008 condensation tracks produced in a C. T. R. Wilson expansion apparatus. Discarding by a definite analytical procedure the isotropically distributed emissions, which are ascribed to unpolarized radiation, the distribution of the remaining 752 tracks is found to be in excellent agreement with the indications of quantum mechanics that (for $K$ electrons) the probability of emission is proportional to the square of the cosine of the angle between the electric vector of the absorbed radiation and the projection of the direction of emission upon a plane normal to the direction of incidence.