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The sub-barrier fusion of40Ar with144,148,154Sm

  • Nuclei
  • Published:
Zeitschrift für Physik A Atoms and Nuclei

Abstract

The cross sections for production of evaporation residues (σ er) and for fusion-fission (σ ff) have been measured for40Ar+144, 148, 154Sm at sub-barrier energies by observation of x-ray emission from radioactive products and by direct,ΔEE identification of fission fragments, respectively. These isotopes span the transition region from spherical (144Sm) to strongly deformed (154Sm) equilibrium shapes. The cross section for fusion,σ fus=σ er+σ ff, is found to vary markedly at low energies with the isotope number and, hence, with the quadrupole collectivity of the target. The thresholds for fusion of148Sm and144Sm are, respectively, ∼3.5 MeV and ∼7 MeV (c.m.) higher than for fusion with154Sm. These differences and the energy dependence of the fusion cross sections are discussed in terms of the effect of nuclear deformation on heavy-ion fusion. A comparative analysis of results for16O+Sm and40Ar+Sm in terms of static deformation indicates thatσ fus for the Ar+Sm system at very low energies is enhanced relative to the prediction for a one-dimensional barrier based on a fit toσ fus for16O+Sm. This may be an indication that additional degrees of freedom (such as formation of a neck or fragment elongation) may be important for fusion with the larger projectile. At energies above the fusion barrier, values ofσ fus for144, 148Sm are nearly equal, but are significantly smaller than for154Sm. This is in contrast to the results of previous experiments with16O projectiles in whichσ fus (16O+148Sm) andσ fus (16O+154Sm) were nearly equal above the barrier. These differences, observed for144, 148Sm and154Sm at energies above the barrier may reflect a new mechanism which is not encompassed by a static theory.

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References

  1. Breit, G., Hull, M., Gluckstern, R.L.: Phys. Rev.87, 74 (1952)

    Google Scholar 

  2. Riesenfeldt, P.W., Thomas, T.D.: Phys. Rev. C2, 711 (1970)

    Google Scholar 

  3. Rasmussen, J.O., Sugawara-Tanabe, K.: Nucl. Phys. A171, 497 (1971)

    Google Scholar 

  4. Stokstad, R.G., Eisen, Y., Kaplanis, S., Pelte, D., Smilansky, U., Tserruya, I.: Phys. Rev. Lett.47, 465 (1978)

    Google Scholar 

  5. Stokstad, R.G.: to be published

  6. Holm, H., Scheid, W., Greiner, W.: Phys. Lett.29 B, 473 (1969)

    Google Scholar 

  7. Jensen, A.S., Wong, C.Y.: Nucl. Phys. A171, 1 (1971)

    Google Scholar 

  8. Kodama, T., Nazareth, R.A.M.S., Möller, P., Nix, J.R.: Phys. Rev. C17, 111 (1978)

    Google Scholar 

  9. Blann, M., Plasil, F.: Phys. Rev. Lett.29, 303 (1972). G.S.I, version of ALICE, W. Reisdorf, unpublished

    Google Scholar 

  10. Freiesleben, H., Hildenbrand, K.D., Pühlhofer, F., Schneider, W.F.W., Bock, R., Harrach, D.V., Specht, H.J.: Z. Physik A292, 171 (1979)

    Google Scholar 

  11. Wong, C.Y.: Phys. Rev. Lett.31, 766 (1973)

    Google Scholar 

  12. Freiesleben, H., Huizenga, J.R.: Nucl. Phys. A224, 503 (1974)

    Google Scholar 

  13. Alexander, J.M., Vaz, L.C., Lin, S.Y.: Phys. Rev. Lett.33, 1487 (1974)

    Google Scholar 

  14. Scobel, W., Mignerey, A., Blann, M., Gutbrod, H.H.: Phys. Rev. C11, 1701 (1975)

    Google Scholar 

  15. Blocki, J., Randrup, J., Swiatecki, W.J., Tsang, C.F.: Ann. Phys. (N.Y.)105, 427 (1977)

    Google Scholar 

  16. Löbner, K.E.G., Vetter, M., Honig, V.: Nuclear Data Tables A7, 495 (1970)

    Google Scholar 

  17. Randrup, J., Vaagen, J.S.: Phys. Lett.77B, 170 (1978)

    Google Scholar 

  18. Raman, S., Milner, W.T., Nestor, C.W. Jr., Stelson, P.H.: Proc. Int. Conf. on Nuclear Structure, Tokyo, (contributed papers) 79 (1977)

  19. Esbensen, H., Winther, H., Broglia, R.A., Dasso, C.H.: Phys. Rev. Lett.41, 296 (1978)

    Google Scholar 

  20. Möller, P., Nix, J.R.: Nucl. Phys. A272, 502 (1976)

    Google Scholar 

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Stokstad, R.G., Reisdorf, W., Hildenbrand, K.D. et al. The sub-barrier fusion of40Ar with144,148,154Sm. Z Physik A 295, 269–286 (1980). https://doi.org/10.1007/BF01412207

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  • DOI: https://doi.org/10.1007/BF01412207

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