Viscosity of saddle-to-scission motion in hot Cf 240 from giant dipole resonance γ yield
1994; American Physical Society; Volume: 72; Issue: 4 Linguagem: Inglês
10.1103/physrevlett.72.470
ISSN1092-0145
AutoresD. J. Hofman, B. B. Back, I. Diószegi, C. P. Montoya, S. Schadmand, R. Varma, P. Paul,
Tópico(s)Advanced NMR Techniques and Applications
ResumoThe giant dipole resonance \ensuremath{\gamma} decay of $^{240}\mathrm{Cf}$ excited to 67 and 93 MeV was measured from the fusion of $^{32}\mathrm{S}$${+}^{208}$Pb. The \ensuremath{\gamma} spectrum and \ensuremath{\gamma}-fission angular correlation are analyzed in terms of prefission and postfission \ensuremath{\gamma}-ray yields using a stattistical model with nuclear viscosity in the fission process. The results show a strong increase in the prescission \ensuremath{\gamma} yield from 67 to 93 MeV. A saddle to scission time ${\mathrm{\ensuremath{\tau}}}_{\mathrm{s}\mathrm{s}\mathrm{c}=}$30\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}21}$ s is extracted from this \ensuremath{\gamma} yield, equivalent to a normalized viscosity \ensuremath{\gamma}\ensuremath{\approxeq}5 and full one-body dissipation.
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