Nuclear Resonance Flourescence
Scattering (NRF) is an excellent method with which to probe low-lying
(photon energies from 0 to 10 MeV) dipole excitations in nuclei because
of the extremely high selectivity of real photons, in exciting such
states. This selectivity stems from the small momentum transfer of
real photons, in contrast to virtual photons from electron scattering
experiments. The development in recent years of high-efficiency germanium
detectors with excellent energy resolution, in conjunction with high-intensity
bremsstrahlung photon beams, has provided the necessary tools to study
the fine structure of magnetic and electric dipole strength distributions
in detail. The fundamental advantage of the photon scattering technique
is that the electromagnetic interaction mechanism is the best-understood
interaction in all of science. This understanding allows one to extract
detailed information about the structure of nuclei and the transitions
between different nuclear states in a completely model independent
way. Thus results from these kinds of experiments are as robust as
any results of nuclear science.
An NRF facility will be established to address some of the most fundamental
questions of nuclear structure at low excitation energies. This facility,
for example, will allow one to probe the transitions between three
major shapes of nuclei, spherical nuclei, quadropole-deformed (football
shaped) nuclei, and tri-axial nuclei (all three axes have different
lengths). The proposed studies will investigate the distribution of
magnetic and electric transition strength, and thus, provide rigorous
tests and guidance to theoretical models. Basic data following from
applicton of this technique can also be used for practical purposes
such as hazardous waste assay and imaging. |
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