The Nuclear Resonance Beamline at ESRF is dedicated to the excitation of nuclear levels by synchrotron radiation. The sources of radiation and optical elements are optimized to provide an intense, highly monochromatic, collimated and stable X-ray beam of small cross-section at the Mossbauer transition energies between 6 and 30 keV. The set-up of the beamline allows to perform studies in diffraction, small angle scattering, forward scattering and incoherent scattering. Equipment is available to maintain the sample at variable temperature and magnetic field. Fast detectors and timing electronics serve to separate the delayed nuclear scattering from the “prompt” electronic scattering and to measure the time spectra of nuclear radiation with sub-nanosecond resolution. The general lay-out and the parameters of the beamline are reported. Typical domains of applications are discussed and illustrated by first experimental results.

Nuclear Resonance Beamline at ESRF

Growth, structural, and magnetic properties of iron nitride thin films deposited by dc magnetron sputtering

The principal ideas of the theory and the main results of the experimental studies of the coherent resonant scattering ofγ-radiation by nuclear ensembles in matter are briefly over-viewed. An analysis of transmission of the Mossbauerγ-radiation and of synchrotron radiation through a nuclear resonant medium is suggested using an approach based on the optical theory. The feasibilities of the nuclear resonant scattering of synchrotron radiation as a new technique for studying the hyperfine interactions and some other phenomena of the physics of condensed matter are considered.

Nuclear resonant scattering of synchrotron radiation

Grazing incidence nuclear multilayer diffraction of synchrotron radiation from a periodic stack of alternating 56Fe and 57Fe layers was observed. Resonant layer fraction, substrate size, flatness, and surface roughness limits were optimized by previous simulations. The isotopic multilayer (ML) sample of float glass/57Fe(2.25 nm)/[56Fe(2.25 nm)/57Fe(2.25 nm)]×15/Al(9.0 nm) nominal composition was prepared by molecular beam epitaxy at room temperature. Purity structure and lateral homogenity of the isotopic ML film was characterized by magnetometry, Auger electron, Rutherford backscattering, and conversion electron Mossbauer spectroscopies. The isotopic ML structure was investigated by neutron and synchrotron Mossbauer reflectometry. Surface roughness of about 1 nm of the flat substrate (curvature radius >57 m) was measured by scanning tunneling microscopy and profilometry. A pure nuclear Bragg peak appeared in synchrotron Mossbauer reflectometry at the angle expected from neutron reflectometry while no ele...

Pure nuclear bragg reflection of a periodic 56fe/57fe multilayer

We present research investigations in the field of multilayer optics in X-ray and extreme ultra-violet ranges (XUV), aimed at the development of optical elements for applications in experiments in physics and in scientific instrumentation. We discuss normal incidence multilayer optics in the spectral region of “water window”, multilayer optics for collimation and focusing of hard X-ray, multilayer dispersing elements for X-ray spectroscopy of high-temperature plasma, multilayer dispersing elements for analysis of low Z-elements. Our research pays special attention to optimization of multilayer optics for projection EUV-lithography (ψ-13nm) and short period multilayer optics.

Multilayer optics for XUV spectral region: technology fabrication and applications

We report the observation of nuclear resonant diffraction of synchrotron radiation by a synthetic multilayer. The nuclear period of the ${[}^{57}$Fe(22 \AA{})/Sc(11 \AA{})/Fe(22 \AA{})/Sc(11 \AA{})\ifmmode\times\else\texttimes\fi{}25 multilayer was chosen to be twice the electronic period to obtain a pure nuclear Bragg reflection. Strong enhancement of the radiative scattering channel provided a fast time response for the $^{57}\mathrm{Fe}$ resonant scattering at the Bragg peak, with a decay time of 4 ns. The nuclear multilayer will be useful as a narrow bandpass monochromator for synchrotron radiation.

N. N. Salashchenko

Papers

Resonant diffraction of synchrotron radiation by a nuclear multilayer.