Results from the RISING Stopped Beam Campaign 2006 Andrea Jungclaus Universidad Autónoma de Madrid NUSTAR Meeting 2007 introduction the RISING setup nuclear structure results summary and outlook

Rare ISotope INvestigations at GSI relativistic radioactive beams (selected by the FRS) highly efficient  -ray detection (15 EUROBALL cluster detectors) + fast beam campaign ( ) g-RISING (fall 2005) stopped beam campaign ( ) passive stopper -  -decays from isomeric states active stopper - ß-decay studies

Ion-by-ion identification with the FRS TOF EE

The setup at the focal plane S4 energy loss  Z x,y tracking time-of-flight  A/q trigger signal (SC41) veto signal (SC43) deceleration ionization chambers (MUSIC41,42) scintillators (SC41,SC42) multiwire chambers (MW41,MW42) SC43 stopper degrader

Best  -spectrometer ever used in isomer spectroscopy ! The RISING  -ray spectrometer 15 EUROBALL Cluster (105 Ge crystals) digital signal processing via 30 XIA DGF modules Absolute efficiency [%]  -energy [keV] DGF TDC MSU GSI  detection efficiency very high  -ray efficiency high granularity (prompt flash problem) S. Pietri et al., NIM Thanks to Cluster owners !

Physics aims of the RISING stopped beam campaign Nb, 86 Tc 54 Ni 130 Cd 204 Pt 106 Zr

Is there evidence for a N=82 shell quenching ? Assumption of a N=82 shell quenching leads to a considerable improvement in the global abundance fit in r-process calculations ! r-process abundances mass number A exp. pronounced shell gap shell structure quenched

132 Sn N=82 Z= Cd A closer look to the region... known mass known half-live r-process waiting point (ETFSI-Q) no direct experimental signature for N=82 quenching most N=82 waiting-point nuclei experimentally not accessible

Indirect evidence for a N=82 shell quenching ? Kautzsch et al., Eur. Phys. J. A9 (2000) 201 from ß-decay studies at ISOLDE Can the anomalous behaviour of 2 + energies in the Cd isotopes towards N=82 be attributed to a change in the N=82 shell gap ?

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

A/q position at S4 S4 position Identification of 130 Cd in the fragmentation of 136 Xe A/q position at S2 Z1Z1 Z2Z2 MUSIC42 vs. MUSIC41 S2 position Z= Cd 4000 identified 130 Cd Ionen in fragmentation (2300 in fission) 750 MeV/u 136 Xe 4 g/cm 2 Be  meas ( 130 Cd)~150 pb

Gamma energy - time correlations DGF time (arb. units) E  (MeV) DGF time (arb. units) ions ions 130 Cd 128 Cd

Singles  -spectrum in delayed coincidence with implanted 130 Cd ions T 1/2 =220(30) ns

 coincidence spectra Gate: 128 keV Gate: 138 keV Gate: 539 keV Gate: 1325 keV 0+0+ (2 + ) (4 + ) (6 + ) (8 + ) SM 130 Cd Decay of the 8 + isomer in 130 Cd T 1/2 =173nsT 1/2 =220(30)ns New results give no evidence for a N=82 shell quenching ! A. Jungclaus, L. Cáceres et al., subm. to Nature

0+0+ (2 + ) (4 + ) (6 + ) (8 + ) 0+0+ (2 + ) (4 + ) (6 + ) (8 + ) 0+0+ (2 + ) (4 + ) (6 + ) (8 + ) E x (MeV) 76 Ni Cd Cd g 9/2 -2  g 9/ / Unexpected scaling of (g 9/2 ) 2 two-body interaction levels are pure (g 9/2 ) -2 states energy spread scales with A -1 not with ħ  =41· A -1/3 as commonly assumed idea of H. Grawe C. Mazzocchi et al., PLB 622 (2005) 45

What about the 2 + anomaly in the Cd isotopes ? T. Rodríguez, J.L. Egido Different behaviour in Z=48 Cd and Z=52 Te can be attributed to deformation effects ! Symmetry conserving configuration mixing calculations with the Gogny force. 48 Cd 8052 Te 80 x0.7

Physics aims of the RISING stopped beam campaign 82 Nb, 86 Tc 54 Ni 130 Cd 204 Pt 106 Zr

Shell structure south of 208 Pb Spokesperson: Zsolt Podolyak, Surrey cold fragmentation of 208 GeV/u main aim: spectroscopy of N=126 isotones 206 Hg, 204 Pt and 202 Os 204 Pt 202 Os

204 Pt populated via 4-proton-knockout from 208 Pb T 1/2 =8.41(16)  s T 1/2 =152(16) ns short isomer: long isomer:

N=126 isotones: (  h 11/2 ) -2,4 I  =10 + isomers 206 Hg Z= Pt Z=78 B. Fornal et al. PRL 87 (2001)  s 1/2 -1 d 3/2 -1  s 1/2 -1 h 11/2 -1  d 3/2 -1 h 11/2 -1  h 11/2 -2 SM 92(8) ns 152(16) ns 2.15(21)  s 8.41(16)  s  d 3/2 -1 d 5/2 -1  d 5/2 -1 h 11/2 -1 ? Results require modification of SPE and/or interactions ! SM Z. Podolyak, S. Steer et al., PRL, in preparation

Physics aims of the RISING stopped beam campaign 82 Nb, 86 Tc 54 Ni 130 Cd 204 Pt 106 Zr

nnppnp T=1, S=0 T=0, S=1 TZ:TZ:+1 0 even-even mirror nuclei (T Z =  1) Studies of the isospin symmetry at N=Z "search for isospin breaking effects" odd-odd N=Z nuclei "T=1 vs. T=0 competition" 54 Ni 82 Nb, 86 Tc

Isospin symmetry and eff. charges near 56 Ni Spokesperson: Dirk Rudolph, Lund main aim: observe I  =10 + isomer in 54 Ni A. Gadea et al., Phys. Rev. Lett. 97 (2006) Mg( 32 S,2n) 54 Ni EUROBALL IV 54 Ni MeV/u

 coincidence spectra gate on 54 Ni 50 ns < t < 1  s Identification of 54 Ni

A=54, T=1 isospin symmetry V BM : charge symmetry breaking component in the NN force J=2 anomaly ! A. Zuker et al., PRL89 (2002) spin (ħ) MED (keV)

Delayed  -spectrum for 54 Ni (50ns-1  s) The big surprise... Where does the 1327 keV line come from ???

Proton radioactivity from the I  =10 + isomer in 54 Ni First observation of excited state proton emission (compe- ting with  -decay) following fragmentation ! D. Rudolph, R. Hoischen et al., PRL, in preparation

Physics aims of the RISING stopped beam campaign 82 Nb, 86 Tc 54 Ni 130 Cd 204 Pt 106 Zr

T=0 - T=1 competition in heavy odd-odd N=Z nuclei Spokesperson: Paddy Regan, Surrey main aim: low-spin level structure in odd-odd 82 Nb, 86 Tc MeV/u

86 Tc 82 Nb ions Identification of odd-odd N=Z 82 Nb and 86 Tc Z A/q ions Setting on 86 Tc N=Z

82 Nb 86 Tc T 1/2 = 133(20) ns T 1/2 = 1.59(20)  s

T=1(T=0)T=1(T=0) T=1 82 Nb 86 Tc 82 Zr 86 Mo Level structure of 82 Nb and 86 Tc compared to their T Z =+1 isobars A. Garnsworthy, P. Regan et al., PRL, in preparation

T=0 and T=1 competition in odd-odd N=Z nuclei Nb,Tc

Physics aims of the RISING stopped beam campaign 82 Nb, 86 Tc 54 Ni 130 Cd 204 Pt 106 Zr

S. Lalkovski, A. Bruce Shape coexistence and the possibility of X(5) behaviour in A~110 nuclei Spokesperson: Alison Bruce, Brighton preliminary

Summary Isomers identified in 54 Ni, 82 Nb, 86 Tc, 130 Cd and 204 Pt first proton-emitting state following fragmentation established in 54 Ni first isomeric decay observed after 6-proton-knockout: 130 Cd Additional observation of more than 25 new isomeric states New information with respect to the reaction mechanism new world record in fragmentation: 27 + high-spin isomer in 148 Tb isomeric ratios cross-section measurement 2006 has been a very successful year for the RISING stopped-beam collaboration ! And the sun will continue to shine...

Physics aims of the RISING active stopper experiments 2007 collective evolution "south" of 208 Pb Benlliure, Regan shape evolution from 190 W to 170 Dy Regan, Benlliure isospin symmetry 54 Ni, 50 Fe, and 46 Cr Fujita, Gelletly, Rubio p-n pairing effects 62 Ge, 70 Kr Gadea, Algora 100 Sn GT strength T. Fästermann

 -decay of 190 Ta  190 W 2+0+2+0+ T 1/2 ~16 sec A. Garnsworthy Online spectrum

L.-L.Andersson, K. Andgren, L.Atanasova, D.L.Balabanski, F.Becker, P.Bednarczyk, J. Benlliure, M.A.Bentley, G.Benzoni, B.Blank, A.Blazhev, C.Brandau, J.Brown, A.M.Bruce, E. Casarejos, L.Cáceres, F.Camera, W.N.Catford, B. Cederwall, F.C.L. Crespi, I.J.Cullen, P. Detistov, Zs.Dombradi, P.D.Doornenbal, E.Estevez, C.Fahlander, G.F.Farrelly, A.B.Garnsworthy, H.Geissel, W.Gelletly, J.Gerl, M.Górska, H. Grawe, J.Grębosz, B. Hadinia, A.Heinz, M.Hellström, C. Hinke, R.Hoischen, G.Ilie, G. Jaworski, E.K.Johansson, J.Jolie, G.A.Jones, A.Jungclaus, A.Kelic, A. Khaplanov, M.Kmiecik, I.Kojouharov, F.G. Kondev, R. Kumar, T.Kurtukian-Nieto, N.Kurz, S. Lalkovski, Z.Liu, A.Maj, S. Mandal, V. Modamio, F.Montes, S.Myalski, M.Pfützner, M. Palacz, S.Pietri, Zs.Podolyák, W.Prokopowicz, P.H.Regan, D.Rudolph, T.Saito, H.Schaffner, S.Schwertel, T.Shizuma, A.J.Simons, G. Simpson, S.J.Steer, S.Tashenov, J. Walker, P.M.Walker, E.Werner-Malento, O. Wieland & H.J.Wollersheim Argonne National Laboratory, Bordeaux, University of Brighton, Universitá di Camerino, Craków, Debrecen, ILL Grenoble, GSI, Japan Atomic Energy Agency, Universität zu Köln, Lund University, Universidad Autónoma de Madrid, Universitá degli Studi di Milano Technische Universität München, University of New Delhi, Universidad de Santiago de Compostela, University of Sofia, KTH Stockholm, University of Surrey, Warsaw University, Yale University, University of York The RISING isomeric decay collaboration Special thanks to the GSI accelerator group ( 2x10 8 p/sec 238 U etc.) !

Workshop on RISING Physics Madrid 6-8 November 2006

ions ions T 1/2 =73(2) ns T 1/2 ~ 20 ns 134 Sn What is the lifetime limit of the current setup ? no trace !