1 / 17

Angular momentum population in fragmentation reactions

Angular momentum population in fragmentation reactions. Zsolt Podolyák University of Surrey. Isomers observed following fragmentation of 208 Pb and 238 U (Z>60). 7. ~15(+3). 5(+5). >20(+7). 2. No. of isomers known(+new). New isomers => nuclear-structure

zia
Télécharger la présentation

Angular momentum population in fragmentation reactions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Angular momentum population in fragmentation reactions Zsolt Podolyák University of Surrey

  2. Isomers observed following fragmentation of 208Pb and 238U (Z>60) 7 ~15(+3) 5(+5) >20(+7) 2 No. of isomers known(+new) New isomers => nuclear-structure Known isomers => reaction mechanism (angular momentum population What is the production cross section for individual states?

  3. “Power” of fragmentation Low spin ~1 ms PROTON RICH I=43/2

  4. isomeric ratio: ● M. Pfützner et al., Phys. Lett. B444 (1998) 32. ■ M. Pfützner et al., Phys. Rev. C65 (2002) 064604. ▲ K. Gladnishki et al., Phys. Rev. C69 (2004) 024617.

  5. Abrasion-ablation model (1-2/3) k = 2 A>10 De Jong, Ignatyuk, Schmidt, NP A613 (1997) 435. “sharp cut-off” approximation:

  6. Analytical formulae ABRABLA M. Pfützner et al., Phys. Rev. C 65 (2002) 054604.

  7. ρth-all states with spin higher than the isomer decay into the isomer

  8. M. Pfützner et al., Phys. Rev. C 65 (2002) 054604. Rexp /ρthe open symbol: known higher-lying isomer (not observed)

  9. Nuclear structure has to be considered 196Pb 270 ns 2.7 MeV 12+ 196Pb: A.K.Singh et al., Nucl. Phys. A707 (2002) 3 186W(16O,6n) at 110 MeV; 170Er(30Si,4n) at 144 MeV fusion-evaporation reaction! φ = Iisomer/(I parallel+I isomer) = Iisomer / I total ρexp=Rexp /φ ρexp- the probability of populating states with higher spin than the isomer –can be compared with theory!

  10. 179W populated in: fragmentation of 208Pb at 1 GeV/u fusion evaporation: 170Er(13C,4n) at 67 MeV

  11. preliminary The highlighted points: Higher lying isomers decay into our isomer

  12. preliminary 177Ta 175Hf 176Ta 179Ta The highlighted points: Higher lying isomers decay into our isomer

  13. Conclusions on the reaction mechanism • Good agreement between experiment and theory (within a factor of 2-3) • predictions for radioactive beams seems to be possible Future: There are new data on: 212Fr 15– 213Fr 29/2+ 212Ra 8+ 214Ra 17– 215Ra 43/2– <= HIGHEST SPIN from fragmentation 215Ac 29/2+ 217Ac 29/2+

  14. To be simulated by P. Detistov Surrey/Sofia

More Related