LAUSR

The impact energy and angular dependence of L X-rays of a thick polycrystalline tungsten (W; atomic number, Z = 74) target induced by 15–25 keV electrons has been measured at different angles varying from 15° to 75° at intervals of 5° using a Si PIN photodiode detector. The variation of measured relative intensity of Ll, Lα, Lβ and Lγ characteristic lines as a function of incidence angle is found to be anisotropic and the measured variation compares well with the PENELOPE simulation results. The angular variation of intensity ratio of Ll/Lα and Lβ/Lα shows anisotropic distribution, whereas the angular variation of the Lγ/Lα ratio exhibits almost isotropic distribution within the uncertainty of measurements. These measured ratios are found to be in good agreement with Monte Carlo (MC) calculations. The measured intensity ratios of Lβ/Lα and Lγ/Lα at a given incidence angle show a linear dependence with impact energy and exhibit good agreement with simulation results; however, the measured intensity ratio of Ll/Lα shows a non-linear variation with the impact energy and yields poor agreement with theoretical calculations.