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Exotic Shapes and High Spin physics with Intense Stable Beams. Shell structure far from spherical magic numbers. Which is the adopted deformation and how it changes with spin and energy ? What are the active orbitals and their correlations ?. How is spin generated ?.
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Exotic Shapes and High Spin physics with Intense Stable Beams
Shell structure far from spherical magic numbers Which is the adopted deformation and how it changes with spin and energy ? What are the active orbitals and their correlations ? How is spin generated ? How much spin can the nucleus sustain ?
Superdeformed world = more than 250 SD rotational bands Octupole vibrations Gyromagnetic factors SD binding energies Triaxial bands + wobbling Particle decay Band termination Large Shell Model calculations
HIGH L A domain rich of new exotic phenomena to be discovered and studied ENERGY GDR Jacobi shape transition fission Rotational damping Chaos Assisted tunneling superdeformation Hyperdeformation Tetrahedral nuclei SPIN
HLHD ExperimentEUROBALL: 64Ni + 64Ni Int.: 1367 Int.: 993 4 x 52 keV • 261 MeV: 52 keV ridge appears Ridge intensity ~5 x 10-5
Search for discrete-line HD spectraEuroball, )E(~ 52 keV A strange feeling of ‘déjà vu’
Triaxiality and Wobbling Experimental results in 163Lu The best ”Wobbler” TSD1 TSD2 TSD3 TSD4 Relative population TSD1: 10% TSD2: 3% TSD3: 1.2% TSD4: 0.9% D.R. Jensen et al., Phys. Rev. Lett. 89 (2002), 142503.
I=0 Looking for Jacoby shape transition Oblate Prolate I=25 spin I=27 I=34
Gates: Time of Flight Residues nuclei (42Ca) Low energy g multiplicity Theory: (Jacoby shape transition) LSD model + Coriolis Splitting A. Maj et al. Nucl. Phys. A731 (2004) 319
High spin states populated in Fusion evaporation reactions 10 11 Ibeam ~ 10 - 10 p/s (5-10 pnA) Limitation: counting rate in the Germanium detectors and/or common acquisition dead-time -4 Fighting to observe VERY WEAK signals… Resolving power ~ 10 Limitation: current arrays
Gamma-ray Detector Development Central Role in Nuclear Physics • Advances in detector technology have resulted in new discoveries. • Innovations have improved detector performance. • Energy resolution • Efficiency • Peak-to-total ratio • Position resolution • Directional information • Polarization • Auxiliary detectors • Tracking is feasible, will provide new opportunities and meet the challenges of new facilities.
high granularity + digital electronics AGATA will be able to handle 10 – 100 times more beam Advanced GAmma Tracking Array Nevt = Np x Nt x s x ed