Optical constants from mirror reflectivities measured at synchrotrons

摘要

Improved mirror reflectivity measurement techniques have been introduced to permit more accurate determinations of optical constants (delta) and (beta) in the complex index of refraction n = 1 - (delta)-i(beta) over the energy range 50 to 5000 eV. When the density has been determined by x-ray or other means, one can calculate the real and imaginary parts f(prime) and f(double prime), of the complex atomic scattering factor f = f(sub o) + f (prime) + if (double prime) from (delta) and (beta). Preliminary results are given for the Ni LIII edge around 852 eV, and the Au M edge region from 2150 to 3500 eV. Since these are the first experimental evaluations of (delta) for these element edges, they are compared with appropriate reservations to semi-empirical tabulations. There is much potential for this technique applied to synchrotron sources.