Experimental Nuclear Physics in ATOMKI Debrecen

Cyclotron laboratory in ATOMKI, Debrecen

The split-pole magnetic spectrometer in ATOMKI

Experimental setup for studying fission (transmission) resonances

Results for

236

U

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

A=100 A=132 Cold fission Compact fission

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 DIAMANT ancillary detector in studying extreme nuclear shapes at large angular momenta

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

DIAMANT 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 168-172 Hf and 126 Ba.

Hotest subject of present-day gamma-spectroscopy!

Which of these is more favorable?

1) 126 Ba 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 126 Ba nucleus at deformations ( b 2 , g ) 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

Big Bite magnetic Spectrometer (BBS) Beams from Ring Cyclotron at RCNP Osaka Beams from AGOR at KVI Groningen

Coincidence measurements with the BBS

Results for the neutron-skin thicknesses

The high-energy branch of the Super-FRS: A versatile setup for kinematical complete measurements of R eactions with R elativistic R adioactive B eams Large-acceptance measurement Exotic beam from Super-FRS Target Experiments  knockout and quasi-free scattering  electromagnetic excitation  charge-exchange reactions  fission  spallation  fragmentation High-resolution measurement

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, ...) g -ray spectroscopy, isospin-dependence in multifragmentation