Program - Brookhaven National Laboratory

done in Ref. [1]. We demonstrate that the obtained results of calculations for total, elastic, inelastic, and
capture cross sections, as well as elastic and inelastic angular distributions correspond to a remarkably
good agreement with experimental data for scattering energies above around a few MeV.
[1] F. S. Dietrich, I. J. Thompson, and T. Kawano, Phys. Rev. C85, 044611 (2012)
Session CD Nuclear Structure and Decay
Monday March 4, 2013
Room: Empire West at 1:30 PM
CD 1 1:30 PM
Gamma-ray Spectroscopy using Rare Isotope Sources ∗
F.G. Kondev, S. Zhu, M.P. Carpenter, R.V.F. Janssens, I. Ahmad, J. Chen, C.J. Chiara, J.P. Greene, T.
Lauritsen, G. Savard, D. Seweryniak
Argonne National Laboratory, Argonne, Illinois 60439, USA
S. Lalkovski
Faculty of Physics, University of Sofia, BG-1164 Sofia, Bulgaria
Rare isotope sources can be used to populate excited structures in nuclei near and away from the line
of stability which are not easily accessible with reactions involving stable heavy-ion beams and targets.
Results will be presented from recent studies with Gammasphere as well as with several germanium clover
and LaBr3(Ce) scintillation detectors. These investigations involve sources with the long-lived, high-K
isomers in 177 Lu (K π =23/2 − , T 1/2=160.44 d) and 178 Hf (K π =16 + , T 1/2=31 y). In the case of 177 Lu,
unusually retarded M3 and E4 transitions depopulating the K π =23/2 − isomer were discovered. The large
hindrance factors deduced from the data provide evidence for significant configuration changes associated
with this isomeric decay. The lifetime of the (K π ,I π )=(8 − ,9 − ) collective level in 178 Hf, populated in the
decay of the K π =16 + isomer, was measured for the first time with two LaBr3(Ce) detectors using the direct
gamma-gamma-time (electronic) technique. The B(M1) value deduced for the 9 − → 8 − in-band transition
was compared with theoretical predictions for competing 2-quasiproton and 2-quasineutron configurations,
and allowed to determine the amplitude of configuration mixing due to the effect of residual protonneutron
interactions. Future studies at the CARIBU facility of the ATLAS accelerator, where a 252 Cf
source (T 1/2=2.645 y) is used to produce and separate neutron-rich fission products, will also be discussed.
∗ This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract
No. DE-AC02-06CH11357.
CD 2 2:00 PM
Nuclear Structure and Induced Depletion of Metastable Isomers
J. J. Carroll, M. S. Litz
US Army Research Laboratory
Metastable nuclear isomers comprise extremely energy-dense materials and have been suggested for a wide
variety of applications ranging from medicine to defense [1]. The energy storage of isomers can exceed
gigaJoules/gram (e. g., 178m2 Hf) with lifetimes of decades or longer (e. g., 180m Ta, with T 1/2 > 10 15
years). The intrinsic energy density of isomers is, however, not by itself sufficient to realize any practical
use: Another necessary component is a means by which to efficiently release the stored energy on a useful
time scale and upon demand [2]. An induced depletion of isomers has previously been demonstrated in four
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