John P. Sutter

An inelastic X-ray spectrometer with 2.2 meV energy resolution

We present a new spectrometer at the Advanced Photon Source for inelastic X-ray scattering with an energy resolution of 2.2 meV at an incident energy of 21.6 keV. For monochromatization, a nested structure of one silicon channel cut and one ‘artificial’ channel cut is used in forward-scattering geometry. The energy analysis is achieved by a two-dimensional focusing silicon analyzer in backscattering geometry. In the first demonstration experiments, elastic scattering from a Plexiglas TM sample and two dispersion curves in a beryllium single crystal were measured. Based on these data sets, the performance of the new spectrometer is discussed. Published by Elsevier Science B.V.

Phonon damping in thin films of Fe

The phonon density of states (DOS) in thin films of polycrystalline α-Fe was measured by inelastic nuclear resonant scattering of synchrotron radiation. The thin-film DOS exhibits significant deviations from the DOS of bulk Fe, which we attribute to phonon lifetime broadening in the confined geometry. The measured DOS can be described with a damped harmonic oscillator model for the phonons with different quality factors Q=25(2) and Q=13(1) for layer thicknesses of 28 and 13 nm, respectively.

A classical Hanbury Brown-Twiss experiment with hard X-rays

The classical Hanbury Brown–Twiss experiment has been conducted with hard X-ray synchrotron radiation at the Advanced Photon Source. The measured spatial coherence area of the X-ray beam is in good agreement with the prediction based on the vertical positron beam size.

Introduction to nuclear resonant scattering with synchrotron radiation

The concepts leading to the application of synchrotron radiation to elastic and inelastic nuclear resonant scattering are discussed. The resulting new experimental techniques are compared to conventional Mössbauer spectroscopy. A survey of situations that favor experiments with synchrotron radiation is offered.

Direct Observation of Low-Energy Sm Phonon in SmRu4P12

Measurements of S ( Q ,ω) of the filled skutterudite SmRu 4 P 12 using inelastic x-ray scattering show a dispersionless mode at 9 meV. Meanwhile, the Sm partial phonon density of states measured by nuclear resonant inelastic scattering shows a strong peak at the same energy. The temperature dependence of the Sm phonon energy suggests that the Sm modes are anharmonic. The comparison of the experimental results in SmRu 4 P 12 with the calculated ones in LaRu 4 P 12 indicates the absence of any significant lattice instability due to 4f electrons.

Relaxation in the spin ice Dy 2 Ti 2 O 7 studied using nuclear forward scattering

The spin dynamics of

Source and optics considerations for new generation high-resolution inelastic X-ray spectrometers

{\mathrm{Dy}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}

Phonon density of states in epitaxial Fe/Cr(001) superlattices

from

Relaxation experiments with synchrotron radiation

8\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}287.3\phantom{\rule{0.3em}{0ex}}\mathrm{K}

Inelastic scattering of synchrotron radiation from electrons and nuclei for lattice dynamics studies

has been investigated using forward scattering of synchrotron radiation from the