Abstract
The fission fragment angular distributions for the system12C +232Th have been measured in the energy range 0.97<Ec.m./VB<1.22. The measured anisotropies have been compared with the predictions of the standard saddle point statistical model, using the second moment of the compound nucleus spin distribution 〈l2〉 deduced from a Wong model fit to the fission excitation function. While the measured anisotropies agree with the standard saddle point statistical model for Ec.m./VB>1.05, they are abnormally large at lower energies. This is also true for the existing measurements of16O and19F +232Th systems. Since for this system pre-equilibrium fission contributions are not expected, this anomaly indicates strong channel coupling effects leading to an increase in 〈l2〉 at sub-barrier energies.
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The authors thank Drs. R.K. Choudhury and A. Saxena for useful discussions, Dr. R.J. Singh for making the thorium target and the Pellectron operation staff for excellent operation of the machine.
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Karnik, A., Kailas, S., Chatterjee, A. et al. Near-barrier fission of the system12C+232Th. Z. Physik A - Hadrons and Nuclei 351, 195–198 (1995). https://doi.org/10.1007/BF01289529
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DOI: https://doi.org/10.1007/BF01289529