Nuclear Dynamical Diffraction Using Synchrotron Radiation*

Content Provider	Semantic Scholar
Author	Brown, Dennis Eugene Brown, I.
Copyright Year	1993
Abstract	The scattering of synchrotron radiation by nuclei is extensively explored in this thesis. From the multipole electric field expansion resulting from time-dependent nonrelativistic perturbation theory, a dynamical scattering theory is constructed. This theory is shown, in the many particle limit, to be equivalent to the semi-classical approach where a quantum mechanical scattering amplitude is used in the Maxwell inhomogeneous wave equation. The Miissbauer specimen whose low-lying energy levels were probed is a ferromagnetic lattice of 57Fe embedded in a yttrium iron garnet (YIG) crystal matrix. The hyperfine fields in YIG thin films were studied at low and room temperature using time-resolved quantum beat spectroscopy. Nuclear hyperfine structure quantum beats were measured using a fast plastic scintillator coincidence photodetector and associated electronics having a time resolution of 2.5 nsec. The variation of the quantum beat patterns near the Bragg [0 0 21 diffraction peak gave a Lamb-Mijssbauer factor of 8.2 + 0.4 . Exploring characteristic dynamical features in the higher order YIG [0 0 lo] reflection revealed that one of the YIG crystals had bifurcated into two different layers. The dynamics of nuclear super-radiance was explored. This phenomenon includes the radiative speedup exhibited by a collective state of particles, and, in striking concurrence, resonance frequency shifts. A speedup of a factor of 4 in the total decay rate and a beat frequency shift of 13 natural resonance linewidths were observed. Nuclear resonance scattering was also found to be a useful way of performing angular interferometry experiments, and it was used to observe the phase shift of a rotated quantum state. On the whole, nuclear dynamical diffraction theory has superbly explained many of the fascinating features of resonant magnetic dipole radiation scattered by a lattice of nuclei.
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://www.slac.stanford.edu/pubs/slacreports/reports15/slac-r-417a.pdf
Language	English
Access Restriction	Open
Subject Keyword	3D film AngularJS Biological specimen CDISC SEND Biospecimens Terminology Dynamical system Embedded system Embedding Energy level Experiment Interferometry Maxwell (microarchitecture) Perturbation theory Photodetector Device Component Quantum mechanics Quantum state Resonance Scattering theory Semiconductor industry Speedup Synchrotrons Telling untruths Yttrium anatomical layer nanosecond
Content Type	Text
Resource Type	Article