Results from the RISING Stopped Beam Campaign 2006

Andrea JungclausUniversidad 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 (2003-2005)g-RISING (fall 2005)stopped beam campaign (2006-2007) passive stopper - -decays from isomeric states active stopper - ß-decay studies

Ion-by-ion identification with the FRS

TOF

E

The setup at the focal plane S4

energy loss Z

x,y tracking

time-of-flight A/qtrigger signal (SC41)veto signal (SC43)

deceleration

ionizationchambers

(MUSIC41,42)scintillators(SC41,SC42)

multiwirechambers

(MW41,MW42)

SC43

stopperdegrader

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

Ab

solu

te e

ffic

ien

cy [

%]

-energy [keV]200 600 1000 14000

10

0

20

30

40

DGFTDC

MSU GSI

detection efficiency

very high -ray efficiencyhigh granularity (prompt flash problem)

S. Pietri et al., NIM

Thanks to Cluster owners !

Physics aims of the RISINGstopped beam campaign 2006

82Nb,86Tc

54Ni

130Cd

204Pt

106Zr

Is there evidence for a N=82 shell quenching ?

Assumption of a N=82 shell quenching leads to a considerableimprovement in the global abundance fit in r-process calculations !

r-p

roce

ss a

bu

nd

ance

s

mass number A

exp.pronounced shell gapshell structure quenched

132Sn

N=82

Z=50

130Cd

A closer look to the region ...

known mass

known half-live

r-process waiting point(ETFSI-Q)

no direct experimentalsignature for N=82 quenching

most N=82 waiting-point nucleiexperimentally not accessible

70 72 74 76 78 80 820

500

1000

1500

60Nd

58Ce

56Ba

54Xe

52Te

48Cd

Ene

rgy

of 2

+ sta

te

Neutron number N

Indirect evidence for a N=82 shell quenching ?

Kautzsch et al., Eur. Phys. J. A9 (2000) 201

from ß-decay studiesat ISOLDE

Can the anomalous behaviour of 2+ energies in the Cd isotopestowards N=82 be attributed to a change in the N=82 shell gap ?

g9/2

Search for the 8+ (g9/2)-2 seniority isomer in 130Cd

two proton holes in the g9/2 orbit

6-proton-knockout from 136Xe: A. Jungclausfission of 238U: M. Górska, M. Pfützner June/July 2006

M. Górska et al., Phys. Rev. Lett. 79 (1997)

A/q

pos

itio

n a

t S

4

S4 position

Identification of 130Cd in the fragmentation of 136Xe

A/q

pos

itio

n a

t S

2

Z1

Z2

MUSIC42 vs. MUSIC41 S2 position

Z=48130Cd

4000 identified 130Cd Ionen in fragmentation (2300 in fission)

750 MeV/u

136Xe

4 g/cm2

Be

meas(130Cd)~150 pb

Gamma energy - time correlations

0.5

1.0

1.5

0.0DGF time (arb. units)

E

(MeV

)

0.5

1.0

1.5

0.0DGF time (arb. units)

6.300 ions 260.000 ions130Cd 128Cd

Singles -spectrum in delayed coincidencewith implanted 130Cd ions

T1/2=220(30) ns

coincidence spectra

128 138 539 1325

Gate: 128 keV

Gate: 138 keV

Gate: 539 keV

Gate: 1325 keV0+

(2+)

(4+)(6+)(8+)

SM130Cd8248

1346

1889

2094

2207

0+

2+

4+6+8+

1325

539

Decay of the 8+ isomer in 130Cd

T1/2=173nsT1/2=220(30)ns

New results give no evidence for a N=82 shell quenching !A. Jungclaus, L. Cáceres et al., subm. to Nature

0+

(2+)

(4+)

(6+)(8+)

0+

(2+)

(4+)(6+)(8+)

0+

(2+)

(4+)(6+)(8+)

1

0

2

Ex (

MeV

)

76Ni482898Cd5048

130Cd8248

g9/2-2 g9/2

-2 g9/2-2

992

1922

2276

2420

1395

2083

2281

2428

1325

18641992/2002

2130

Unexpected scaling of (g9/2)2 two-body interaction

2+-8+ levels arepure (g9/2)-2 states

2+-8+ energy spread

scales with A-1

not with ħ=41·A-1/3

as commonly assumed

idea of H. GraweC. Mazzocchi et al.,PLB 622 (2005) 45

What about the 2+ anomaly in the Cd isotopes ?

T. Rodríguez, J.L. Egido

Different behaviour inZ=48 Cd and Z=52 Tecan be attributed todeformation effects !

Symmetry conservingconfiguration mixingcalculations with theGogny force.

48Cd80 52Te80

x0.7 x0.7

Physics aims of the RISINGstopped beam campaign

82Nb,86Tc

54Ni

130Cd

204Pt

106Zr

Shell structure south of 208PbSpokesperson: Zsolt Podolyak, Surrey

cold fragmentationof 208Pb@1 GeV/u

main aim:spectroscopy of N=126 isotones206Hg, 204Pt and 202Os

204Pt

202Os

204Pt populated via 4-proton-knockout from 208Pb

T1/2=8.41(16) s

T1/2=152(16) ns

short isomer:

long isomer:

N=126 isotones: (h11/2)-2,4 I=10+ isomers

206Hg Z=80 204Pt Z=78

B. Fornal et al.PRL 87 (2001)212501

s1/2-1d3/2

-1

s1/2-1h11/2

-1

d3/2-1h11/2

-1

h11/2-2

SM

92(8) ns

152(16) ns

2.15(21) s8.41(16) s

d3/2-1d5/2

-1

d5/2-1h11/2

-1

?

Results require modification ofSPE and/or interactions !

SM

Z. Podolyak, S. Steer et al., PRL, in preparation

Physics aims of the RISINGstopped beam campaign

82Nb,86Tc

54Ni

130Cd

204Pt

106Zr

nn ppnp

T=1, S=0

T=0, S=1

TZ: +1 0 -1

even-even mirror nuclei (TZ=1)

Studies of the isospin symmetry at N=Z

"search for isospin breaking effects"od

d-o

dd

N=

Z n

ucl

ei"

T=

1 vs

. T=

0 co

mp

etit

ion

"

54Ni

82Nb,86Tc

Isospin symmetry and eff. charges near 56NiSpokesperson: Dirk Rudolph, Lund

main aim:observe I =10+ isomer in 54Ni

A. Gadea et al., Phys. Rev. Lett. 97 (2006) 152501

24Mg(32S,2n)54Ni EUROBALL IV54Ni

58Ni @ 550 MeV/u

coincidence spectra

gate on 54Ni50 ns < t < 1 s

Identification of 54Ni

A=54, T=1 isospin symmetry

VBM: charge symmetry breaking component in the NN force

J=2 anomaly !

A. Zuker et al., PRL89 (2002) 142502

0 2 4 6 8 10spin (ħ)

ME

D (

keV

)

0

100

-100

0

100

-100

Delayed -spectrum for 54Ni (50ns-1s)

The big surprise ...

Where does the 1327 keV line come from ???

Proton radioactivity from the I=10+ isomer in 54Ni

First observation of excitedstate proton emission (compe-ting with -decay) followingfragmentation !

D. Rudolph, R. Hoischen et al., PRL, in preparation

Physics aims of the RISINGstopped beam campaign

82Nb,86Tc

54Ni

130Cd

204Pt

106Zr

T=0 - T=1 competition in heavy odd-odd N=Z nuclei

Spokesperson: Paddy Regan, Surrey

main aim:low-spin level structurein odd-odd 82Nb, 86Tc

43

41

41 43

107Ag @ 750 MeV/u

86Tc

82Nb

20.000 ions

Identification of odd-odd N=Z 82Nb and 86Tc

Z

A/q

4.500 ions

Setting on 86Tc

N=Z

82Nb 86Tc

T1/2= 133(20) ns T1/2= 1.59(20) s

T=1 (T=0) T=1 (T=0)T=1 T=1

82Nb 86Tc82Zr 86Mo

Level structure of 82Nb and 86Tc comparedto their TZ=+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 RISINGstopped beam campaign

82Nb,86Tc

54Ni

130Cd

204Pt

106Zr

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 54Ni, 82Nb, 86Tc, 130Cd and 204Pt first proton-emitting state following fragmentation established in 54Ni

first isomeric decay observed after 6-proton-knockout: 130Cd

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 148Tb isomeric ratios cross-section measurement

2006 has been a very successful year for the RISINGstopped-beam collaboration !

And the sun will continue to shine ...

Physics aims of the RISINGactive stopper experiments 2007

collective evolution"south" of 208PbBenlliure, Regan

shape evolution from190W to 170Dy

Regan, Benlliure

isospin symmetry54Ni, 50Fe, and 46Cr

Fujita, Gelletly, Rubio

p-n pairing effects62Ge, 70Kr

Gadea, Algora

100Sn GT strengthT. Fästermann

-decay of 190Ta 190W

2+0+

T1/2 ~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 MilanoTechnische Universität München, University of New Delhi, Universidad de Santiagode 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 (2x108 p/sec 238U etc.) !

Workshop on RISING PhysicsMadrid 6-8 November 2006

100.000 ions 340.000 ions

T1/2=73(2) ns

T1/2 ~ 20 ns

134Sn

What is the lifetime limit of the current setup ?

no trace !