Measurement of Giant Dipole Resonance width at low temperature: A new experimental perspective

Abstract

The systematic evolution of the giant dipole resonance (GDR) width in the temperature region of 0.9 ~ 1.4 MeV has been measured experimentally for 119Sb using alpha induced fusion reaction and employing the LAMBDA high energy photon spectrometer. The temperatures have been precisely determined by simultaneously extracting the vital level density parameter from the neutron evaporation spectrum and the angular momentum from gamma multiplicity filter using a realistic approach. The systematic trend of the data seems to disagree with the thermal shape fluctuation model (TSFM). The model predicts the gradual increase of GDR width from its ground state value for T > 0 MeV whereas the measured GDR widths appear to remain constant at the ground state value till T ~ 1 MeV and increase thereafter indicating towards a failure of the adiabatic assumption of the model at low temperature.

Submitted to Physics Letters B (6 pages, 3 figures, 1 table)

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Cited by in corpus (13)

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• Experimental Determination of $\eta$/$s$ for Finite Nuclear Matter
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• Experimental signature of collective enhancement in nuclear level density
• Effects of thermal shape fluctuations and pairing fluctuations on the giant dipole resonance in warm nuclei
• Giant dipole resonance in ${}^{201}$Tl at low temperature
• Nuclear excitations within microscopic EDF approaches : pairing and temperature effects on the dipole response
• Pairing effect in thermal shape fluctuation model on the width of giant dipole resonance
• Giant dipole resonance in ${}^{88}$Mo from phonon damping model's strength functions averaged over temperature and angular momentum distributions
• Examination of level density prescriptions in the interpretation of high energy gamma-ray spectra
• Neutron response of the LAMBDA spectrometer and neutron interaction length in BaF2
• Giant dipole resonance in highly excited nuclei