undressing (to fiddle the decay probability )

1. Ex=509 keV, T1/2~20 ns 0+ 2+ 456 keV gamma E0, 0+->0+ e- conversion decay 0+ undressing (to fiddle the decay probability) Fully stripping the nucleus of its atomic electrons (in-flight) ‘switches off’ the electron conversion decay branches. Result is that the bare nuclear isomeric lifetime is increased compared to ‘atomic’ value. (important in explosive stellar scenarios).

2. 74Kr isomer from 92Mo fragmentation at GANIL. 456 keV 2+->0+ transitions decays (a) too fast (500 ns flight time) & (b) too slow for measured value of 2+ state (~25 ps) ?

3. 92Mo fragmentation on natNi target 76Rb 69Se 67Ge C. Chandler et al. Phys. Rev. C61 (2000) 044309

4. Two level mixing The gamma-rays emitted from nuclear reactions exhibit angular distributions that can be expressed as follow: Q2,Q4: Solid angle corrections, due to the finite size of the detectors

5. Band Crossings • Backbending can be interpreted as the crossing of two bands • The ‘G’ band (Ground state) is a fully paired configuration • The ‘S’ band (Super or Stockholm) contains one broken pair

6. Backbending

7. Systematics of B(E2)s In near stable and proton rich nuclei there is a fixed relationship between B(E2) and E2+ “GRODZINS RULE” However, in neutron rich nuclei, this should break down, and the link between B(E2) and deformation WILL be more complicated.

11. (iii) (ii) (i) Ebeam ~15-20% above Coulomb barrier beam target Z N Deep inelastic collisions Can not use fusion-evaporation reactions to study high-spin states in beta-stable and neutron-rich systems.

12. projectile Final fragment Excited pre-fragment target hotspot Projectile Fragmentation Reactions Energy (velocity) of beam > Fermi velocity inside nucleus ~30 MeV/u Can ‘shear off’ different combinations of protons and neutrons. Large variety of exotic nuclear species created, all at forward angles with ~beam velocity.

13. Nuclear Reactions – very schematic! Near the line of stability • Gamma-ray induced • no Coulomb barrier • Neutron induced • low-spin states • no Coulomb barrier • Light charged particles, e.g. p, d, t, a • Coulomb barrier • low-spin states (“capture”) (“fast”)

14. DCO Ratios Df is the angle between two planes opened by each detector and the beam axis probability (intensity) for this specific configuration, e.g. the intensity of transition g2, determined in detector 2, gated on the transition g1 in detector 1

15. DCO Ratios Df is the angle between two planes opened by each detector and the beam axis probability (intensity) for this specific configuration, e.g. the intensity of transition g2, determined in detector 2, gated on the transition g1 in detector 1

16. 178Hf 16+, 4-qp Isomer

17. 31 y 16+ 2.4 MeV 0+ • 28 g - boils 120 t of water • 1 g - equivalent to 650 lbs. of TNT Courtesy to John Becker, LLNL

18. SPIEGEL ONLINE - 14. August 2003, 15:27 Pentagon-Pläne Handliches Höllenfeuer Das US-Militär entwickelt einen neuartigen Nuklearsprengstoff, der schon in kleinsten Mengen ungeheure Vernichtungskräfte entfesseln, zugleich aber auch in Kleinstwaffen eingesetzt werden kann. Experten warnen bereits vor einem neuen globalen Wettrüsten. New Scientist, 2003 Nuklearexplosion: Isomere können in großem und kleinem Maßstab eingesetzt werden Some Applications

19. Triggering of 178mHf using X-rays Texas/AFRL/SNL Collaboration/Phys. Rev. Lett. 82 (1999) 695

20. Triggering of 178mHf using X-rays – cont. ANL/LANL/LLNL /Phys. Rev. Lett. 87 (2001) 072503

21. Texas/AFRL/SNL Collaboration Phys. Rev. Lett. 82 (1999) 695 After the mixing b|Ip,K1> +a|Ip,K2> a|Ip,K1> - b|Ip,K2> Can K-Mixing explain the results by Collins et al? Before the mixing Ip,K1 Ip,K2 and K2>K1 V • two levels with the same Ipand <90 keV above the isomer • must have I=15,16 or 17, e.g. high spin • must have very different K • V is very small (~eV!)

22. a a n 178Hf ANU Experiment Incomplete fusion 178Hf 5He 9Be 176Yb g

23. 178Hf ANU Experiment - cont.