Experimental Nuclear Physicsin ATOMKI Debrecen

Cyclotron laboratory in ATOMKI, Debrecen

The split-pole magnetic spectrometer in ATOMKI

Experimental setup for studying fission (transmission) resonances

Results for 236U

P.G. Goldstone et al., PRC 18 (1978) 1706A. Krasznahorkay et al., PRL 80

(1998) 2073

On the depth of the third minimum

On the height of the fission barriers

History of the 3. Minimum

Möller … PLB 40 (1972) 329

Blons … PRL 41 (1978) 1282

(Howard, Möller, ADNDT 25 (1980) 218 )

Cwiok … PLB 322 (1994) 304

Clusterization

Cold fission

Compact fission

A=100 A=132

Collaborations

Forshungszentrum Karlsruhe, Inst. f. Kernphysik

Nuclear Astrophysics at ATOMKI

Main topics:

– Underground nuclear physics (LUNA collaboration)– Ultra low energy collisions

• Electron screening• Stopping power

– Astrophysical p-process• Reaction rates• Optical potentials

– Exotic nuclear physics– Resonance strength determinations– Half-life studies

Collaborations:

– LUNA: Italy/Germany/Portugal/Hungary– Uni Bochum, Germany– Demokritos Inst. Greece– RIKEN, Japan– TU Darmstadt, Germany– Uni Basel, Switzerland– Notre Dame University, USA

Use of the Use of the DIAMANTDIAMANT ancillary detector ancillary detector in studying extreme nuclear shapes at in studying extreme nuclear shapes at

large angular momentalarge angular momenta

C.E.N.B.G. (Bordeaux) and ATOMKI (Debrecen) (2000-present)

DIAMANT DIAMANT in search for hyperdeformation in search for hyperdeformation

DIAMANT has been used in EUROBALL experiments aiming at, e.g., the identification of rotational structures characteristic for hyperdeformed (HD) shapes in nuclei 168-172Hf and 126Ba. Hotest subject of present-day gamma-spectroscopy!Hotest subject of present-day gamma-spectroscopy!

Which of these is more favorable?

1) 126Ba is predicted to be the best candidate for having stable HD structures:

Theoretical predictions (macroscopic calculations by J. Dudek), indicate that the energy minimum (dark blue regions) of the 126Ba nucleus at deformations (

2,) corresponding to hyperdeformed

shapes remains stable upto very high spins (I). At a critical spin of I > 74 ħ the nucleus becomes unstable against fission.

Different other gamma spectroscopy experiments in Legnaro

Collaboration with GANIL, France

Giant resonance studies

Beams from AGOR at KVI GroningenBeams from Ring Cyclotron

at RCNP Osaka

Big Bite magnetic Spectrometer (BBS)

Coincidence measurements with Coincidence measurements with the BBSthe BBS

Results for the neutron-skin thicknesses

Experiments

knockout and quasi-free scattering

electromagnetic excitation

charge-exchange reactions

fission

spallation

fragmentation

Physics goals

single-particle occupancies, spectral functions, correlations, clusters, resonances beyond the drip lines

single-particle occupancies, astrophysical reactions (S factor), soft coherent modes, giant resonance strength, B(E2)

Gamow-Teller strength, spin-dipole resonance, neutron skins

shell structure, dynamical properties

reaction mechanism, applications (waste transmutation, ...)

-ray spectroscopy, isospin-dependence in multifragmentation

The high-energy branch of the Super-FRS:

A versatile setup for kinematical complete measurements of

Reactions with Relativistic Radioactive Beams

Exotic beam from Super-FRS

Target

Large-acceptance measurement

High-resolution measurement