Search

A procedure is described for the detailed characterization of multilayer analyzers which can be effectively applied to their design, optimization and application for absolute x-ray spectrometry. An accurate analytical model has been developed that is based upon a simple modification of the dynamical Darwin-Prins theory to extend its application to finite multilayer systems. Its equivalence to the optical E&M solution of the Fresnel equations at each interface is demonstrated by detailed calculation comparisons for the reflectivity of a multilayer throughout the angular range of incidence of 0 to 90° . A special spectrograph and experimental method is described for the measurement of the absolute reflectivity characteristics of the multilayer. The experimental measurements at three photon energies in the 100-2000 eV region are fit by the analytical modified Darwin-Prins equation (MDP) for I( 0), generating a detailed characterization of two "state of the art" multilayers, a sputtered tungsten-carbon of 2d 21 70 A and a molecular lead stearate of 2d 100 A. The fitting parameters that are determined in this procedure are applied to help establish the structural characteristics of the particular multilayer.

A procedure is described for a detailed characterization of multilayer analyzers that can be effectively applied to their design, optimization, and application for absolute x-ray spectrometry in the 100 to 10,000 eV photon energy region. An accurate analytical model has been developed that is based upon a simple modification of the dynamical Darwin-Prins theory to extend its application to finite multilayer systems and to the low energy x-ray region. Its equivalence to the optical E&M solution of the Fresnel equations at each interface is demonstrated by detailed comparisons for the reflectivity of a multilayer throughout the angular range of incidence of 0° to 90°. A special spectrograph and an experimental method are described for the measurement of the absolute reflectivity characteristics of the multilayer. The experimental measurements at three photon energies in the 100 to 2000 eV region are fit by the analytical modified Darwin-Prins equation (MDP) for 1(0), generating a detailed characterization of two state-of-the-art multilayers: sputtered tungsten-carbon with 2d 70 A and a molecular lead stearate with 2d 100 A. The fitting parameters that are determined by this procedure are applied to help establish the structural characteristics of these multilayers.

A detailed characterization has been established for the new, high-sensitivity double-emulsion Kodak Direct Exposure Film (DEF). The experimental data base consisted of density-versus-exposure measurements that were duplicated at several laboratories for x radiations in the 1000–10,000-eV region. The absorption and geometric properties of the film were determined, which, along with the density-exposure data, permitted the application of a relatively simple analytical model description for the optical density, D, as a function of the intensity, I (photons/μm2), the photon energy, E (eV), and the angle of incidence, θ, of the exposing radiation. A detailed table is presented for the I values corresponding to optical densities in the 0.2–2.0 range and to photon energies, E (eV), in the 1000–10,000-eV region. Experimentally derived conversion relations have been obtained that allow the density values to be expressed as either diffuse or specular. Also presented here is a similar characterization of the complementary, single-emulsion x-ray film, Kodak SB-5 (or 392). For the 1000–10,000-eV region this x-ray film is appreciably less sensitive but has higher resolution.

Relatively simple mathematical models are developed to determine the optical density as a function of the x-ray intensity, its angle of incidence, and its photon energy in the 100–10,000-eV region for monolayer and emulsion types of photographic films. Semiempirical relations are applied to characterize a monolayer film (Kodak 101-07) and an emulsion-type film (Kodak RAR 2497); these relations fit calibration data at nine photon energies well within typical experimental error.