Azimuthal and polar angle dependence of L X-ray differential cross-sections of Yb at 59.54 keV photon energy

• The azimuthal and polar angle dependence of L X-ray for Yb is investigated.
• The azimuthal angle dependence of Ll and Lα X-rays are observed.
• The azimuthal anisotropy of Lβ and Lγ X-rays are not observed.
• The polar anisotropy of Ll and Lα X-rays are observed.
• The polar anisotropy of Lβ and Lγ X-rays are not observed.

The azimuthal and polar angle dependence of L X-ray was investigated in the same experimental setup to remove the existing ambiguity about alignments measurements. We measured Ll, Lα, Lβ and Lγ X-ray differential cross sections of Yb for several different azimuthal angles (30°, 20°, 10°, 0°, −10° and −20°) and polar angles (90°, 100°, 110°, 120°, 130° and 140°) at 59.54 keV photon energy by using a Si(Li) detector. The azimuthal angle dependence of Ll and Lα X-rays were observed. The azimuthal anisotropy of Lβ and Lγ X-rays were not observed. On the other hand, differential cross-sections for Lβ and Lγ X-rays were found independent on the polar angle within experimental error, those for Ll and Lα X-rays depended on the polar angles. Azimuthal and polar angles dependence of L X-ray differential cross-sections contrast with the other experimental and theoretical results, which report evidence of the isotropic emission of Ll and Lα X-rays following photoionization.