246 research outputs found
Influence of damping on the excitation of the double giant resonance
We study the effect of the spreading widths on the excitation probabilities
of the double giant dipole resonance. We solve the coupled-channels equations
for the excitation of the giant dipole resonance and the double giant dipole
resonance. Taking Pb+Pb collisions as example, we study the resulting effect on
the excitation amplitudes, and cross sections as a function of the width of the
states and of the bombarding energy.Comment: 8 pages, 3 figures, corrected typo
A multi-detector array for high energy nuclear e+e- pair spectrosocopy
A multi-detector array has been constructed for the simultaneous measurement
of energy- and angular correlation of electron-positron pairs produced in
internal pair conversion (IPC) of nuclear transitions up to 18 MeV. The
response functions of the individual detectors have been measured with
mono-energetic beams of electrons. Experimental results obtained with 1.6 MeV
protons on targets containing B and F show clear IPC over a wide
angular range. A comparison with GEANT simulations demonstrates that angular
correlations of pairs of transitions in the energy range between 6 and
18 MeV can be determined with sufficient resolution and efficiency to search
for deviations from IPC due to the creation and subsequent decay into
of a hypothetical short-lived neutral boson.Comment: 20 pages, 8 figure
Pyroglutamate Abeta pathology in APP/PS1KI mice, sporadic and familial Alzheimer’s disease cases
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