1 / 22

Paddy Regan for the Stopped Beam Rising Collaboration Dept. of Physics, University of Surrey p.regan@surrey.ac.uk

Paddy Regan for the Stopped Beam Rising Collaboration Dept. of Physics, University of Surrey p.regan@surrey.ac.uk. The (Stopped Beam) RISING Experimental Campaign at GSI: The Mapping of Isomeric Decays and Beta-Delayed Spectroscopy in Highly Exotic Nuclei. RISING

forest
Download Presentation

Paddy Regan for the Stopped Beam Rising Collaboration Dept. of Physics, University of Surrey p.regan@surrey.ac.uk

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. Paddy Regan for the Stopped Beam Rising Collaboration Dept. of Physics, University of Surrey p.regan@surrey.ac.uk The (Stopped Beam) RISING Experimental Campaign at GSI: The Mapping of Isomeric Decays and Beta-Delayed Spectroscopy in Highly Exotic Nuclei

  2. RISING Rare Isotopic Spectroscopic INvestigations @ GSI = 15 x Cluster germaniums for (the most) exotic gamma-ray spectroscopy

  3. Stopped RISING Physics Aims & Philosophy • Study the evolution of single-particle / shell structure (shell melting ?) as a function of N:Z ratio. • 56Ni (N=28 ; Z=28) 100Sn (N=50: Z=50) • 132Sn (N=82 : Z=50) • 208Pb (N=126 : Z=82) • Study the structure of nuclei with the most exotic proton-to-neutron ratios: • Proton drip-line N=Z • Neutron-rich ‘terra incognita’. • Nuclear ‘symmetries’ and relevance of quantum numbers: • Isospin, T (N:Z ratio) • Nuclear Deformation,b2 (p-n interactions) • Angular Momentum Projection, K (axial symmetry) • Critical Point Symmetries e.g., X(5) • Reaction mechanism studies in fragmentation.

  4. Physics aims of the RISING stopped beam campaign 204Pt ~190W Terra Incognita 82Nb,86Tc 130Cd 54Ni 106Zr

  5. Stopped RISING Array @ GSI: 15 x 7 element CLUSTERs Photopeak efficiency >10% at 1.3 MeV. XIA-DGF electronics

  6. 40  detection efficiency 30 DGF TDC 20 Absolute efficiency [%] 10 MSU GSI 0 0 200 600 1000 1400 -energy [keV] The RISING -ray spectrometer 15 EUROBALL Cluster (105 Ge crystals) digital signal processing via 30 XIA DGF modules S. Pietri et al., Acta Phys. Pol.B38 (2007)p1255 very high -ray efficiency high granularity (prompt flash problem) Best-spectrometer ever used in isomer spectroscopy !

  7. N=Z line Particle Identification Sum of data from 90Rh, 86Tc and 82Nb settings with 107Ag beam A.B. Garnsworthy et al., Acta Phys. Pol. B38 (2007) p1265 & L. Caceres et al., Acta Phys. Pol. B38 (2007) p1271

  8. 82Nb 86Tc T1/2= 133(20) ns T1/2= 1.59(20) s

  9. Search for the 8+ (g9/2)-2 seniority isomer in 130Cd 6-proton-knockout from 136Xe: A. Jungclaus fission of 238U: M. Górska, M. Pfützner June/July 2006 two proton holes in the g9/2 orbit g9/2 M. Górska et al., Phys. Rev. Lett. 79 (1997)

  10. Singles -spectrum in delayed coincidence with implanted 130Cd ions T1/2=220(30) ns ENERGY TIME

  11.  coincidence spectra 539 138 1325 128 2207 8+ (8+) 6+ (6+) 2094 4+ (4+) Gate: 128 keV 1889 539 2+ (2+) Gate: 138 keV 1346 Gate: 539 keV 1325 Gate: 1325 keV 0+ 0+ 130Cd82 SM 48 Decay of the 8+ isomer in 130Cd T1/2=220(30)ns T1/2=173ns New results give no evidence for a N=82 shell quenching A. Jungclaus, L. Cáceres et al.,submitted to Nature

  12. Shell structure south of 208Pb Spokesperson: Zsolt Podolyak, Surrey cold fragmentation of 208Pb@1 GeV/u 204Pt Related reaction theory by J.Tostevin et al., 202Os main aim: spectroscopy of N=126 isotones 206Hg, 204Pt and 202Os

  13. 204Pt populated via 4-proton-knockout from 208Pb long isomer: T1/2=8.41(16) s short isomer: T1/2=152(16) ns S. Steer, Zs. Podolyak et al., Acta Phys. Pol. B38 (2007) p1283

  14. 204Pt Z=78 Z. Podolyak, S. Steer et al., PRL, in preparation h11/2-2 152(16) ns d5/2-1h11/2-1 d3/2-1h11/2-1 ? s1/2-1h11/2-1 8.41(16) s d3/2-1d5/2-1 s1/2-1d3/2-1 SM B. Fornal et al. PRL 87 (2001)212501 Results require modification of SPE and/or interactions ! N=126 isotones: (h11/2)-2,4 I=10+ isomers 206Hg Z=80 92(8) ns 2.15(21) s SM

  15. Active Stopper RISING • Isomer spectroscopy requires isomers! • Would like to be able to do beta-delayed spectroscopy on (neutron-rich) fragments. • Problem….implanting ~10 GeV energy followed by ~200 keV in same pixel. • Solution? ‘Logarithmic’ pre-amps.

  16. 5 cm x 5 cm DSSSD (16 strips by 16 strips = 256 pixels) 3 positions across focal plane, room for 2 detectors deep.

  17. R. Kumar et al.,

  18. 205Au126 electron conversion!! h11/2 → d3/2M4 transition (half-life a few seconds…..) New single particle (hole) information around 208Pb core. K L

  19. 207 keV 2+ → 0+ On-line beta-delayed gated 190Ta ions….. Transitions fed in daughter 190W nucleus by beta decay. First time we see same nucleus via both isomer decay AND beta-decay. N. Al-Khomashi, PhD thesis

  20. 190W isomer decay from 208Pb beam

  21. GSI-EA (Fri. 20th April 2007) 11 New Stopped RISING Proposals All with UK involvement, 4 with UK (co)spokespersons)

More Related