"The Breakup threshold anomaly of the 6Li + 116Sn system from the elastic scattering measurements "
NIKIT DESHMUKH, THE MAHARAJA SAYAJIRAO UNIVERSITY OF BARODA
(id #38)
Seminar: NoPoster: Yes
Invited talk: No
N. N. Deshmukh, S. Mukherjee, S. Appannababu, D. Patel, N. L. Singh and P. K. Rath
Department of Physics, The M. S. University of Baroda, Vadodara 390 002, India
B.K. Nayak, D.C. Biswas, E.T. Mirgule, S. Santra, L.S. Danu, Y.K. Gupta, A. Saxena and R. K. Choudhary
Nuclear Physics Division, BARC, Mumbai 400085, India
Rakesh kumar
Inter-University Accelerator Center, New Delhi 110067, India
In nuclear reactions, the elastic scattering experiments plays a vital role to provide the information of nuclear properties. The study of interacting potentials with tightly bound nuclei as a function of energy, near the Coulomb barrier has been useful to investigate the Threshold Anomaly (TA) [1,2], where the real and imaginary parts of the potential shows a rapid variation and is consistent with the dispersion relation [3,4]. However, the scenario changes drastically when the weakly bound nuclei such are involved. Here the projectile being weakly bound couples to the breakup channels as a result the breakup cross section becomes larger than the fusion cross section at the sub barrier energies [5]. This contradicts to the usual TA and this effect is named as Breakup Threshold Anomaly (BTA) [4]. In BTA, the imaginary part shows the increasing trend with a small reduction in the real part of the potential near the barrier. This is due to a repulsive real polarization potential [6] and opening of the breakup channel near and below the Coulomb barrier.
In the present work we have also tried to investigate the BTA by performing elastic scattering experiment below and above the Coulomb barrier viz., 20, 21, 22, 23, 24, 26, 30, 35 and 40 MeV energy range, using the weakly bound projectile 6Li. The beam was delivered by the 14UD Pelletron accelerator of the TIFR/BARC facility in Mumbai, India. The beam was bombarded on a 450 µg/cm2, self supported enriched 116Sn (≥ 98%) target and the elastically scattered 6Li ions were detected by three solid state silicon surface barrier ∆E + E telescopic arrangements. Two monitor detectors were used for the absolute normalization. The angular distributions were measured in steps of 2.5° to 5° at angles θlab ≤ 173° for lower energies and θlab ≤ 105° for higher energies.
Optical model analysis has to be carried out to extract the optical potential parameters and reaction cross sections using two different potential models, namely (i) a phenomenological Woods-Saxon potential (WSP) and (ii) the Sao Paulo double folding potential (SPP). The above mentioned aspects are at the preliminary level and thus will be presented in the Conference.
[1] G. R. Satchler, Phys. Rep. 199, 147 (1997).
[2] M. A. Nagarajan, C. C. Mahaux, and G. R. Satchler, Phys. Rev. Lett 54, 1136 (1985)
[3] M. S. Hussein et al., Phys. Rev. C 76, 019902(E) (2007).
[4] M. S. Hussein et al., Phys. Rev. C 73, 044610 (2006).
[5] L. F. Canto et al., Phys. Rep. 424, 1 (2006).
[6] C. Mahaux et al., Nucl. Phys. A 449, 354 (1986).
Department of Physics, The M. S. University of Baroda, Vadodara 390 002, India
B.K. Nayak, D.C. Biswas, E.T. Mirgule, S. Santra, L.S. Danu, Y.K. Gupta, A. Saxena and R. K. Choudhary
Nuclear Physics Division, BARC, Mumbai 400085, India
Rakesh kumar
Inter-University Accelerator Center, New Delhi 110067, India
In nuclear reactions, the elastic scattering experiments plays a vital role to provide the information of nuclear properties. The study of interacting potentials with tightly bound nuclei as a function of energy, near the Coulomb barrier has been useful to investigate the Threshold Anomaly (TA) [1,2], where the real and imaginary parts of the potential shows a rapid variation and is consistent with the dispersion relation [3,4]. However, the scenario changes drastically when the weakly bound nuclei such are involved. Here the projectile being weakly bound couples to the breakup channels as a result the breakup cross section becomes larger than the fusion cross section at the sub barrier energies [5]. This contradicts to the usual TA and this effect is named as Breakup Threshold Anomaly (BTA) [4]. In BTA, the imaginary part shows the increasing trend with a small reduction in the real part of the potential near the barrier. This is due to a repulsive real polarization potential [6] and opening of the breakup channel near and below the Coulomb barrier.
In the present work we have also tried to investigate the BTA by performing elastic scattering experiment below and above the Coulomb barrier viz., 20, 21, 22, 23, 24, 26, 30, 35 and 40 MeV energy range, using the weakly bound projectile 6Li. The beam was delivered by the 14UD Pelletron accelerator of the TIFR/BARC facility in Mumbai, India. The beam was bombarded on a 450 µg/cm2, self supported enriched 116Sn (≥ 98%) target and the elastically scattered 6Li ions were detected by three solid state silicon surface barrier ∆E + E telescopic arrangements. Two monitor detectors were used for the absolute normalization. The angular distributions were measured in steps of 2.5° to 5° at angles θlab ≤ 173° for lower energies and θlab ≤ 105° for higher energies.
Optical model analysis has to be carried out to extract the optical potential parameters and reaction cross sections using two different potential models, namely (i) a phenomenological Woods-Saxon potential (WSP) and (ii) the Sao Paulo double folding potential (SPP). The above mentioned aspects are at the preliminary level and thus will be presented in the Conference.
[1] G. R. Satchler, Phys. Rep. 199, 147 (1997).
[2] M. A. Nagarajan, C. C. Mahaux, and G. R. Satchler, Phys. Rev. Lett 54, 1136 (1985)
[3] M. S. Hussein et al., Phys. Rev. C 76, 019902(E) (2007).
[4] M. S. Hussein et al., Phys. Rev. C 73, 044610 (2006).
[5] L. F. Canto et al., Phys. Rep. 424, 1 (2006).
[6] C. Mahaux et al., Nucl. Phys. A 449, 354 (1986).
