 |
| Gammasphere
is a very sensitive detector of
gamma rays submitted from nuclei.
|
The core of an atom is the nucleus.
Existing models of nuclear structure
have been challenged recently by the
discovery at several national laboratories
of nuclei with extended shapes and
other unusual characteristics. These
properties were observed in nuclei
at the extremes of excitation energy,
angular momentum, deformation, and
other parameters. For instance, superdeformed
nuclei with a 2:1 axis ratio were
found that spin very rapidly and exhibit
identical gamma-ray decay properties.
Other nuclei have a diffuse "halo"
of loosely bound neutrons. These properties,
found only in laboratories on Earth,
may be important in the synthesis
of heavier elements in giant and exploding
stars. Evidence also has been found
for superheavy nuclei, which may be
the first indication of the long-sought
"island of stability" beyond the previously
known nuclei found in nature (i.e.,
uranium). These studies have been
conducted at Argonne, Lawrence Berkeley,
and Oak Ridge national laboratories.
Scientific Impact:
Studies of unstable isotopes (different
forms of chemical elements) helps
scientists understand the genesis
of elements in stars and evolution
of stellar systems. Nuclei with extended
shapes and other properties near the
extremes also test existing models
and fundamental theories of the nucleus.
Social Impact: These
studies help answer questions about
the constituents and history of the
universe, extending human understanding
of nature and contributing to improvements
in science education. In addition,
although basic research is by definition
a search for new knowledge without
regard to its practical implications,
such work often contributes to technologies
with commercial value; examples include
computers, lasers, and cancer treatments.
Reference: "Observation
of a Discrete-Line Superdeformed Band
up to 60 h in 152D," P.J. Twin et
al., Phys Rev. Lett. 55:
1380 (1986); "Superdeformed Shapes
at High Angular Momentum," P.J. Nolan
and P.J. Twin, Ann. Rev. Nucl.
Part. Sci. 38: 533-62 (1988);
"Superdeformed Nuclei," R.V.F. Janssens
and T-L. Khoo, Ann. Rev. Nucl.
Part. Sci. 38 (1988).
URL:
http://www-gam.lbl.gov
Technical Contact:
Dr. Paul Fallon, pfallon@lbl.gov
Press Contact: Jeff
Sherwood, DOE Office of Public Affairs,
202-586-5806
SC-Funding Office:
Office of High Energy and Nuclear
Physics |
