2 Synchrotron-Radiation-Based Energy-Domain Mössbauer …
99
2.4.7 Summary and Perspective of Quasielastic Scattering
of Mössbauer Gamma Rays
Quasielastic scattering technique using SR-based Mössbauer γ-rays is a promising
technique to directly reveal the microscopic dynamics in unique timescales between
nanosecond and microsecond.
The quasielastic scattering technique using TDI will be improved by further developments, such as an increase in detection detector efficiency, an increase in the solid
angle of γ-ray detection by introducing more detectors, and an increase in γ-ray
count rate using more γ-ray lines for measurement. These improvements greatly
help in extracting the intermediate scattering function from the spectrum and directly
visualizing the decay of the intermediate scattering function.
QEGS using
57 Fe nuclear Bragg monochromator is expected to measure the
dynamics faster than the timescale covered by current QEGS using TDI, for example,
up to 100 ps. Therefore, the development of the energy-domain QEGS system and the
combination study with the TDI system expand the accessible timescales by QEGS
using the Mössbauer γ-rays. In addition, a further combination study with other
techniques, such as quasielastic neutron scattering, allows us to further understand
microscopic dynamics in complex systems. These improvements and combination
studies are important to understand the macroscopic properties and functions from
a microscopic level for both basic science and industrial applications. Furthermore,
the TDI system can be applied for studies on dynamical correlations in quantum
systems [136].
The fourth-generation SR shows much higher spatial coherency and higher
condensing properties than the third-generation SR used for the studies introduced
here. Microscopic dynamics of each spatial region in complex systems can be
measured selectively by focusing on the γ-rays. Such QEGS system with focused
γ-rays is useful, for example, to understand dynamical heterogeneity of glass formers.
Acknowledgements The author is grateful to all collaborators and would like to thank all of
the staff at the Institute for Integrated Radiation and Nuclear Science, Kyoto University, National
Institutes for Quantum and Radiological Science and Technology, Japan Atomic Energy Agency,
SPring-8, and the Photon factory of KEK for their support.
References
1. For example, N.N. Greenwood, T.C. Gibb, Mössbauer Spectroscopy. (Chapman and Hall,
London, 1971)
2. D.C. Champeney, Rep. Prog. Phys. 42, 1017 (1979). and references therein
3. Please see Chap. 1 in this book
4. M. Seto, S. Kitao, Y. Kobayashi, R. Haruki, T. Mitsui, Y. Yoda, X.W. Zhang, Yu. Maeda,
Phys. Rev. Lett. 84, 566 (2000)
5. M. Seto, Y. Yoda, S. Kikuta, X.W. Zhang, M. Ando, Phys. Rev. Lett. 74, 3828 (1995)
99
2.4.7 Summary and Perspective of Quasielastic Scattering
of Mössbauer Gamma Rays
Quasielastic scattering technique using SR-based Mössbauer γ-rays is a promising
technique to directly reveal the microscopic dynamics in unique timescales between
nanosecond and microsecond.
The quasielastic scattering technique using TDI will be improved by further developments, such as an increase in detection detector efficiency, an increase in the solid
angle of γ-ray detection by introducing more detectors, and an increase in γ-ray
count rate using more γ-ray lines for measurement. These improvements greatly
help in extracting the intermediate scattering function from the spectrum and directly
visualizing the decay of the intermediate scattering function.
QEGS using
57 Fe nuclear Bragg monochromator is expected to measure the
dynamics faster than the timescale covered by current QEGS using TDI, for example,
up to 100 ps. Therefore, the development of the energy-domain QEGS system and the
combination study with the TDI system expand the accessible timescales by QEGS
using the Mössbauer γ-rays. In addition, a further combination study with other
techniques, such as quasielastic neutron scattering, allows us to further understand
microscopic dynamics in complex systems. These improvements and combination
studies are important to understand the macroscopic properties and functions from
a microscopic level for both basic science and industrial applications. Furthermore,
the TDI system can be applied for studies on dynamical correlations in quantum
systems [136].
The fourth-generation SR shows much higher spatial coherency and higher
condensing properties than the third-generation SR used for the studies introduced
here. Microscopic dynamics of each spatial region in complex systems can be
measured selectively by focusing on the γ-rays. Such QEGS system with focused
γ-rays is useful, for example, to understand dynamical heterogeneity of glass formers.
Acknowledgements The author is grateful to all collaborators and would like to thank all of
the staff at the Institute for Integrated Radiation and Nuclear Science, Kyoto University, National
Institutes for Quantum and Radiological Science and Technology, Japan Atomic Energy Agency,
SPring-8, and the Photon factory of KEK for their support.
References
1. For example, N.N. Greenwood, T.C. Gibb, Mössbauer Spectroscopy. (Chapman and Hall,
London, 1971)
2. D.C. Champeney, Rep. Prog. Phys. 42, 1017 (1979). and references therein
3. Please see Chap. 1 in this book
4. M. Seto, S. Kitao, Y. Kobayashi, R. Haruki, T. Mitsui, Y. Yoda, X.W. Zhang, Yu. Maeda,
Phys. Rev. Lett. 84, 566 (2000)
5. M. Seto, Y. Yoda, S. Kikuta, X.W. Zhang, M. Ando, Phys. Rev. Lett. 74, 3828 (1995)