1 Historical Developments and Future Perspectives …
3
1.1 Introduction
“Nuclear resonance fluorescence of γ -radiation” without recoil was discovered and
explained by R. L. Mößbauer in 1958 (“Kernresonanzfluoreszenz von Gammastrahlung in Ir
191 ” [1, 2]) and later named “Mössbauer effect” and the related spectroscopy consequently Mössbauer spectroscopy. Already shortly after this
earth-breaking discovery thoughts went from absorption to scattering and diffraction experiments. Scattering experiments were reported by Black and Moon early
as 1960 [3], followed by grazing incidence experiments by Bernstein and Campbell [4], and diffraction experiments by Black et al. [5]. New phenomena such as
interference between electronic and nuclear scattering, enhancement of the radiative
channel (speed-up), and suppression of the incoherent channels were discovered and
clarified. This early period has been reviewed by Smirnov (experiments) [6], and by
van Bürck (theory) [7]. At that time synchrotron radiation has already been known
since 1947, however, mainly as a nuisance for high energy accelerator experiments.
In the remaining part of the chapter, nuclear resonance and synchrotron radiation
will be introduced. The following historical chapter shall in general highlight, on the
example of nuclear resonance scattering, the challenges in scientific developments,
which are not only scientificly but also technically and politically driven.
The main part is devoted to an overview of the richness of nuclear resonance techniques and spectroscopies, which span from investigations of magnetic and electronic
properties, static and dynamic, and structural dynamics on various energy and time
scales, to γ -optics and other fundamental research. Eventually, selected examples
of applications will not only showcase the unique fields of research accessible with
nuclear resonance techniques but also look in the bright future with the new light
sources at the horizon.
1.1.1 Nuclear Resonance
Nuclear Resonance Scattering (NRS) with synchrotron radiation (SR) combines the
outstanding properties of the Mössbauer effect with those of synchrotron radiation.
Since its first convincing observation in 1984 [8] a rapid development of the technique
with many facets followed. Thanks to the outstanding properties of 3rd generation
synchrotron radiation sources nuclear resonance techniques are nowadays known
for their extreme energy resolution and timing properties offering a wide range of
applications.
Nuclear resonance techniques including Mössbauer spectroscopy are related to
the recoiless resonant scattering, absorption, and emission of x-rays and γ -rays
1 by
atomic nuclei. This effect is the same as in the atomic shell and well known e.g.
from the yellow emission lines of sodium where light is absorbed and re-emitted by
a transition of an electron between the 3p and the 3s atomic levels. Though the basics
1 we use the term γ -ray for x-rays coming from a nucleus.
3
1.1 Introduction
“Nuclear resonance fluorescence of γ -radiation” without recoil was discovered and
explained by R. L. Mößbauer in 1958 (“Kernresonanzfluoreszenz von Gammastrahlung in Ir
191 ” [1, 2]) and later named “Mössbauer effect” and the related spectroscopy consequently Mössbauer spectroscopy. Already shortly after this
earth-breaking discovery thoughts went from absorption to scattering and diffraction experiments. Scattering experiments were reported by Black and Moon early
as 1960 [3], followed by grazing incidence experiments by Bernstein and Campbell [4], and diffraction experiments by Black et al. [5]. New phenomena such as
interference between electronic and nuclear scattering, enhancement of the radiative
channel (speed-up), and suppression of the incoherent channels were discovered and
clarified. This early period has been reviewed by Smirnov (experiments) [6], and by
van Bürck (theory) [7]. At that time synchrotron radiation has already been known
since 1947, however, mainly as a nuisance for high energy accelerator experiments.
In the remaining part of the chapter, nuclear resonance and synchrotron radiation
will be introduced. The following historical chapter shall in general highlight, on the
example of nuclear resonance scattering, the challenges in scientific developments,
which are not only scientificly but also technically and politically driven.
The main part is devoted to an overview of the richness of nuclear resonance techniques and spectroscopies, which span from investigations of magnetic and electronic
properties, static and dynamic, and structural dynamics on various energy and time
scales, to γ -optics and other fundamental research. Eventually, selected examples
of applications will not only showcase the unique fields of research accessible with
nuclear resonance techniques but also look in the bright future with the new light
sources at the horizon.
1.1.1 Nuclear Resonance
Nuclear Resonance Scattering (NRS) with synchrotron radiation (SR) combines the
outstanding properties of the Mössbauer effect with those of synchrotron radiation.
Since its first convincing observation in 1984 [8] a rapid development of the technique
with many facets followed. Thanks to the outstanding properties of 3rd generation
synchrotron radiation sources nuclear resonance techniques are nowadays known
for their extreme energy resolution and timing properties offering a wide range of
applications.
Nuclear resonance techniques including Mössbauer spectroscopy are related to
the recoiless resonant scattering, absorption, and emission of x-rays and γ -rays
1 by
atomic nuclei. This effect is the same as in the atomic shell and well known e.g.
from the yellow emission lines of sodium where light is absorbed and re-emitted by
a transition of an electron between the 3p and the 3s atomic levels. Though the basics
1 we use the term γ -ray for x-rays coming from a nucleus.