Horizontal Evaluation (Topical Review) on K-Isomers in Deformed Nuclei Filip G. Kondev 17 th NSDD Network meeting, St. Petersburg, Russia, 2007 Nuclear Engineering Division Outline  Introduction & Motivation (very brief!)  Present Status & Outlook

2 Introduction & Motivation Potential for many applications: Astrophysics, Activation analysis; Medicine; Detector calibration standards; Nuclear energy  KiKiKiKi jj jj j K f =0 long-lived states due to conservation of the K quantum number Probe various aspects of nuclear structure at extreme conditions: interplay between intrinsic & collective motion limits of conservation of K-quantum number (robustness of symmetry) seniority dependence of major residual interactions in deformed nuclei Exotic nuclear structure studies: radioactive targets – high-spin/seniority – e.g. 178m Hf, 177m Lu radioactive beams – the future – physics at extreme conditions

3  Deformed nuclei with axially-symmetric shape  High-K orbitals near the Fermi surface  5/2[402], 7/2[404], 9/2[514] 5/2[512], 7/2[514], 7/2[633], 9/2[624] K Isomers: Where to find them? Mass 180 region : Yb (Z=70)-Ir(Z=77) K jj jj j 7-qp K=49/2

4 The Best Known Isomer … Jag has been always in an excited state! he will have a very long lifetime! and

5 Isomers Research at Argonne  Availability of a variety of HI beams and a flexible beam pulsing system from 4 He up to 238 U/ time-range from ns up to years!  Existence of high-efficiency detector systems, e.g. Gammasphere & FMA Studying Isomers at extreme conditions: Heavy nuclei/ Proton Drip Line/ Neutron Rich Nuclei/High-spin & Seniority

6 K-Isomers Evaluation  Aim – to evaluate properties of all K-isomers in deformed nuclei – including Ex, K, J , T1/2, BR, ICC, B(XL) and f - no such systematic study exists, but it is very much needed!  Why not using ENSDF directly? we (in ENSDF) don’t treat explicitly the K-quantum number long updating time (6-8 years) E  (X ) (I ,K   i (I ,K   f =  K- – degree of K-forbiddenness F=   (X )/  w (X ) – hindrance factor f =(F) 1/ – reduced hindrance per degree of K-forbiddenness – gives yardstick for “goodness” of the K- quantum number 20< f  <100  K-hindered decay f <10 - anomalous decay f v >100 – perhaps something is wrong! for M1 and E2 decays

7 K-Isomers Evaluation-cont.  The data are evaluated in ENSDF format have agreed on general policies – tried to follow the ENSDF policies as much as possible specialized codes were developed  The evaluation will be completed in the next 1-2 years and it will be made available to all NSDD centers and published can easily be used to update ENSDF will make specific recommendations to improve ENSDF – introduction of the K-quantum number explicitly it will be continuously updated the need to include other classes of isomers – will depend on the needs of the community

8  Prediction of energies, J  – OK: WS (Nilsson) with pairing  Prediction of T1/2? – not so good! K-Isomers Evaluation-cont.

9 Collaborators Supported by the Office of Nuclear Physics, U.S. DOE T. Kibedi & G.D. Dracoulis Australian National University, Canberra, Australia Encouragement and advice from many colleagues: R. Janssens (ANL), P. Chowdhury (UML), P. Walker (U. Surrey), and others