Optical constants of sputtered beryllium thin films determined from photoabsorption measurements in the spectral range 20.4 250 eV

Autor: Andrey Sokolov, R. S. Pleshkov, Nikolay I. Chkhalo, M.G. Sertsu, Vladimir N. Polkovnikov, N. N. Tsybin, N. N. Salashchenko, Franz Schäfers, M. V. Svechnikov, Alexey Lopatin
Rok vydání: 2020
Předmět:
Popis: In this work, the refractive index of beryllium in the photon energy range 20.4–250 eV was experimentally determined. The initial data include measurements of the transmittance of two free-standing Be films with thicknesses of 70 nm and 152 nm, as well as reflectometric measurements of similar films on a substrate. Measurements were carried out at the optics beamline of the BESSY II synchrotron radiation source. The absorption coefficient β was found directly from the transmission coefficient of the films, and the real part of the polarizability δ was calculated from the Kramers–Kronig relations. A comparison is carried out with results obtained 20 years ago at the ALS synchrotron using a similar methodology.
Databáze: OpenAIRE