SearcharxivSearch

arXiv subjects

Thomas S. Toellner

Publications and source records attributed to Thomas S. Toellner.

2 recordsLinked to original sources

Exo-interferometric Phase Determination of X rays

The time-dependent phase change of x rays after transmission through a sample has been determined experimentally. We used an x-ray interferometer with a reference sample containing sharp nuclear resonances to prepare a phase-controlled x-ray beam. A sample with similar resonances was placed in the beam but outside of the interferometer; hence our use of the term ``exo-interferometric.'' We show that the phase change of the x rays due to the sample can be uniquely determined from the time-dependent transmitted intensities. The energy response of the sample was reconstructed from the phase and the intensity data with a resolution of 23neV.

physics.optics

Measuring velocity of sound with nuclear resonant inelastic x-ray scattering

Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crystalline and noncrystalline materials. Advantages and limitations of this method are elucidated.

cond-mat