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Isoscalar transition rates via $sup 40$Ca, $sup 208$Pb($alpha$$,$$alpha$') at 79 MeV

Journal Article · · Phys. Rev., C, v. 13, no. 3, pp. 1072-1082
OSTI ID:4012638
The inelastic scattering of $alpha$ particles from $sup 40$Ca and $sup 208$Pb has been studied at a bombarding energy of 79.1 MeV. Isoscalar transition rates have been extracted for the 2$sup +$ level at 3.90 MeV, the 3$sup -$ levels at 3.73, 6.29, and 6.58 MeV, and the 5$sup -$ level at 4.48 MeV in $sup 40$Ca. These have been compared to previous results, and a slight energy dependence is evident. In the case of $sup 208$Pb, the isoscalar transition rates have been extracted for the 2$sup +$ level at 4.09 MeV, the 3$sup -$ level at 2.62, and the 5$sup -$ levels at 3.22 and 3.73 MeV. The analysis of the Coulomb and nuclear interference for the 2$sup +$ level at 4.09 MeV indicates that $beta$/sub Coulomb/ =1.2$beta$/sub nuclear/. A folding model analysis has been made for the 3.73-MeV (3$sup -$) and 3.90-MeV (2$sup +$) levels in $sup 40$Ca and the 2.62-MeV (3$sup - $) and 4.09 MeV (2$sup +$) levels in $sup 208$Pb. This analysis, using an effective $alpha$ particle, bound nucleon interaction determined from 79-MeV elastic $alpha$-scattering data, is compared to a standard deformed optical potential analysis. Agreement between the two analyses is best for the 2$sup +$ state in $sup 208$Pb and worst for the 3$sup -$ state in $sup 40$Ca. The explicit inclusion of exchange effects tends to reduce the discrepancy between the two reaction models. (AIP)
Research Organization:
Cyclotron Institute and Physics Department, Texas AandM University, College Station, Texas 77843
NSA Number:
NSA-33-031759
OSTI ID:
4012638
Journal Information:
Phys. Rev., C, v. 13, no. 3, pp. 1072-1082, Journal Name: Phys. Rev., C, v. 13, no. 3, pp. 1072-1082; ISSN PRVCA
Country of Publication:
United States
Language:
English