S. Kahane et R. Moreh, ELASTIC-SCATTERING CROSS-SECTIONS OF 11.4 MEV PHOTONS FROM PB-206, PB-207, PB-208, BI-209, AND TA-181, Physical review. C. Nuclear physics, 50(4), 1994, pp. 2000-2009
Monoenergetic photons of 11.4 MeV, originating from the Ni(n, gamma) r
eaction were elastically scattered from three isotopically enriched le
ad targets, a Bi-209 target, and a Ta-181 target. Cross sections for t
he lead isotopes at theta = 90-degrees and 140-degrees differ signific
antly from predictions based on known giant dipole resonance (GDR) par
ameters showing marked structures in this region of energy. The cross
sections for Bi-209 and Ta-181 are in agreement with a previous measur
ement. The Ta-181 cross section is the only case where agreement is fo
und with calculations based on known GDR parameters. New GDR parameter
s for Bi-209 were deduced by combining the present elastic scattering
with those from previous measurements, leading to kappa(GDR) = 0.35 +/
- 0.06.