Angular distribution measurement of various L₃X-ray transitions

Abstract

The presence of the magnetic quadrupole term in addition to the electric dipole one in the multipole expansion of the radiation field is reflected in the angular distribution of the X-ray transition. To extend the previous works the authors studied the angular distribution of different L3 X-ray lines of Ba, Sm and Er experimentally for proton impact at 0.23, 0.28 and 0.35 MeV bombarding energies respectively, using a Si(Li) detector. The anisotropy parameter ratios of the Ll and L alpha transitions were found to be 5.2+or-2.8, 5.5+or-0.7 and 6.9+or-1.5. Angular distributions of Tb L-shell X-rays were also measured by a high resolution crystal spectrometer for 0.556 MeV amu-1 nitrogen ions, a value of 3.5+or-2.5 was obtained for the anisotropy parameter ratio. These ratios deviate significantly from the theoretical ones.