Speaker
Prof.
Attila Krasznahorkay
(Institute of Nuclear Research, Atomki)
Description
The predicted variety of exotic nuclear shapes, and heavy clusterizations in
the actinide region still represent big challenges for the contemporary
experimental investigations.
Recently, the fission probability as a function of the excitation energy has been
measured with high energy resolution using the (d,pf) reaction on different targets
in order to study exotic nuclear shapes. The resonances could be described as being
members of rotational bands with moments of inertia characteristic to super- and
hyperdeformed nuclear shapes [1-4].
For the first time the depth of the third potential minimum was experimentally
determined by applying a method of the statistical level density analysis of
band head energies [2,4]. The method was tested in the case of the well known
second potential minimum [3]. A rather deep third minimum was found in 234U
(EIII=3.1(4) MeV) as well as in 236U (EIII=2.7(4) MeV) [4] in agreement with recent
theoretical expectations [5].
The excitation energy of the lowest-lying hyperdeformed transmission resonance and
the energy dependence of the fission isomer population probability allowed us to
determine the height of the inner fission barrier and also its penetrability
parameter for 236U. In this way the long lasting uncertainties in determining the
height of the inner potential barrier in Uranium isotopes ('Thorium anomaly') was
resolved in the picture of the triple-humped fission barrier [4].
The possibility of heavy clusterization in such highly deformed states was also
investigated by measuring the mass and energy distributions of the ejected
charged particles as a function of the excitation energy nearby the fission
resonances corresponding to hyperdeformed nuclear states.
An overview of the field, our latest experimental results and future plans will be
presented.
References:
[1] A. Krasznahorkay et al., Phys. Rev. Lett. 80 (1998) 2073.
[2] A. Krasznahorkay et al., Phys. Lett. B 461 (1999) 15.
[3] M. Hunyadi et al., Phys. Lett. B 505 (2001) 27.
[4] M. Csatlos et al., Phys. Lett. B 615 (2005) 175.
[5] S. Cwiok et al., Phys. Lett. B 322 (1994) 304.
Primary author
Prof.
Attila Krasznahorkay
(Institute of Nuclear Research, Atomki)
