‐
•
•
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Peter Reiter
IKP, University of Cologne for the MINIBALL collaboration
3 RD EGAN Workshop 24 th – 27 th June, 2013, University of Liverpool

Outline
- Physics case
- MINIBALL@REX-ISOLDE - Perspectives
“Island of inversion” N=20
Coulomb excitation & transfer reactions
(Darmstadt, Cologne, Munich)
Phys. Lett. B, 700 ( 2011) 181
Phys. Rev. Lett. 105 , 252501 (2010)
Phys. Rev. Lett. 103 , 012501 (2009)
Phys. Rev. Lett. 94 , 172501 (2005)
26,28,29,30 Na
29,30,31,32 Mg
Towards the doubly magic 78 Ni with Coulomb excitation and nucleon transfer reactions around 68 Ni
(CERN, Leuven, Munich)
66,67,68 Ni
67,68,69,70,71,73
72,74,76,78,79,80
Cu
Zn
Phys. Rev. C 84 , 064323 (2011)
Phys. Rev. C 82 , 064309 (2010)
Phys. Rev. C. 79, 014309 (2009)
Phys. Rev. Lett. 100, 112502 (2008)
Phys. Rev. C. 78 , 047301 (2008)
Phys. Rev. Lett. 99, 142501 (2007)
Phys. Rev. Lett. 98, 122701 (2007) transfer reactions at N=28
(Darmstadt, Munich)
46 Ar

Outline
- Physics case
- MINIBALL@REX-ISOLDE - Perspectives
Towards the doubly magic 100 Sn
(Lund, CERN)
Phys. Rev. C 87, 017301 (2013)
106,107,108,109,110 Sn
107,108 In
Phys. Rev. C 86, 031302(R) (2012)
100,102,104 Cd
Eur. Phys. J. A (2012) 48 : 105
Eur. Phys. J. A 44 (2010) 355
Phys. Rev. C 80 , 054302 (2009)
Phys. Rev. Lett. 101, 012502 (2008)
Phys. Rev. Lett. 98, 172501 (2007) g-factors in Te isotopes
(Darmstadt, Madrid)
132,134,136 Te
B(E2) measurements around 132 Sn
(Darmstadt, Munich)
122,123,124,128 Cd
138,140,142,144 Xe
140,142,148 Ba

Outline
- Physics case
- MINIBALL@REX-ISOLDE - Perspectives
Shapes and collectivity in the rare earth region
(Darmstadt, Saclay, Oslo)
138,140 Nd
140,142 Sm
142 Gd
144 Dy Collectivity near Z=50
(York, Darmstadt)
116,118 Te
Shapes and collectivity between Kr and Sr
(York, Cologne, Munich, Orsay,
Liverpool, Grenoble, Saclay)
72 Kr
88,92,94,96 Kr
93,95,97,99 Rb
96 Sr
Nucl. Phys. A 899 (2013) 1
Phys.Rev.Lett. 108, 062701 (2012)
Phys.Rev.Lett. 98, 072501 (2007)

Outline
- Physics case
- MINIBALL@REX-ISOLDE - Perspectives
Shapes and collectivity in light Po, Rn nuclei
(York, Jyväskylä)
206 Po
202,204 Rn
Octupole collectivity in heavy Rn, Ra isotopes
(Liverpool)
220,222 Rn
222,224 Ra Nature 497 (2013) 199
Shapes in Hg, Pb, Po nuclei
(Leuven, Liverpool, Jyväskylä)
182,184,186,188 Hg
188,190,192,194,196,198 Pb
196,198,200,202 Po

Outline
-
Physics case
- MINIBALL@REX-ISOLDE -
Island of Inversion - Perspectives
RIB Production:
• 1,4 GeV protons
• various targets
• ionization
• mass separation in GPS/HRS
• 800 RIBs available
New
• Astatine beam production and ionization spectroscopy
• S. Rothe et al.,
Nat. Commun. 4:1835 doi:
10.1038/ncomms2819 (2013).

Outline
-
Physics case
- MINIBALL@REX-ISOLDE -
Island of Inversion - Perspectives
Isomeric beams @ ISOLDE
• technique based on in-source laser spectroscopy
(
Fedosseev, V. N. et al. Rev. Sci. Instrum. 83, 02A903 (2012))
• set the laser frequency to select and maximize the production of the isomer of interest
6 -
68 Cu
6 -
722
1 + 0


70 Cu
3 -
1 +
6 (g.s.)
1 +
3 -
6 -
242
101
0



1 + (g.s.) g -Spectroscopy with Cu isomer beams: I. Stefanescu et al. PRL 98 , 122701 (2007), E.
Rapisarda et al.
PRC 84 , 064323 (2011)
• new case 123 Sn beam
T. Kroell et al., experiment IS524

Outline
-
Physics case
- MINIBALL@REX-ISOLDE -
Island of Inversion - Perspectives
RIB preparation @ REX-ISOLDE Charge breeding:
• cooling and bunching of the
RIB in the REXTRAP
• breeding to higher charge states in the EBIS to A/q<4.5
• breeding time up to 400 ms
• A/q selection
Re-acceleration
• acceleration of the ions in the
REX-LINAC
• beam energy: 0,8-3,0 MeV/u
Acceleration up to Ra achieved

Outline
-
Physics case
- MINIBALL@REX-ISOLDE -
Island of Inversion - Perspectives
MINIBALL
Coulomb excitation setup segmented Si detector for particle detection (DSSSD)
• 16 rings (front side)
• 96 strips (back side)
• angle coverage: θ lab
= 16-55 °
• ΔE-E measurement possible (pad)
N. Warr, et al., Eur. Phys. J. A (2013) 49: 40

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
123

( d
3 / 2
)

2

(
122
Cd ) ??

( h
11 / 2
)

2

(
122
Cd ) ???
xxx??
(9/2 + ) 691
(5/2 + ,7/2 + ) 591
(5/2 + ) 463
(5/2 + ,7/2 + ) 409
(1/2 + ) 116
3/2 + 0
(9/2 ) 440
11/2 316
Physics aim:
Enhanced quadrupole collectivity observed in 122,124 Cd (IS411)
S. Ilieva et a., to be published
Coupling of odd neutron to even core
 reveals which orbitals contribute to collectivity
Additional finding from JYFLTRAP:
Level scheme needs major revision as 11/2 isomer is not at 316 keV but
144(4) keV
A. Kankainen et al., Phys. Rev. C 87 , 024307
H. Huck et al., PRC 40, 1384 (1989) A.-L. Hartig , Th. Kröll, et al, TU Darmstadt

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
123
• First Coulex of odd Cd isotope at REX-ISOLDE
• Beam intensity: ≈ 9 ·10 4 /s
• Beam composition:
- 100% Cd
- RILIS beam
- ratio g.s./isomer varied by RILIS setting
(thanks to B. Marsh)
≈ 66% 123m Cd and ≈ 33% 123 Cd
Energy [keV]
Observables: cross section (  B(E2)’s), g
-ray angular distributions (  spin/parity), ...
First results:
• New transition observed: 463 keV, ...
• Branchings and intensities are not consistent with level scheme in literature
Analysis by Anna-Lena Hartig
(MSc project) [Th. Kröll, S. Ilieva, S. Bönig, M. Thürauf, M. Scheck]

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
72
- a rarity that gives a deeper understanding of effective nucleon-nucleon interaction
Spokesperson: B.S. Nara Singh, IS478, proposed in 2007
72 Kr at 200 MeV
104 Pd 2 mg/cm 2
CD+PAD
Considerable efforts over 5 years
– beam development and several attempts
~150 counts in
710 keV line
May 2012
~ 28 % effect http://npg.york.ac.uk/structure_current.html
B.S. Nara Singh, U of York for the IS478 collaboration

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
Shape transition and coexistence in neutron-deficient rare earth nuclei:
Coulomb excitation of 140 Sm ground-state deformation
Gogny HFB
A.Görgen et al. Univ. Oslo
ISOLDE IS495 (July 2012) beam
 140 Sm @ 2.85 A MeV
 RILIS
 2

10 5 pps @ Miniball configuration mixing caclculation
J.-P. Delaroche et al.
Phys. Rev. C 81, 014303 (2010) target
 94 Mo, 2 mg/cm 2
2
1
 
0
1

94
Mo
(0 + )
Q s
4 +
Prolate
Oblate
2 +
Q s
0 +
Doppler correction projectile Doppler correction target

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
IS495: Differential cross sections – GOSIA analysis
63
   cm

71

71
   cm

82

82
   cm

95

95
   cm

113

M.Klintefjord, et al., Univ. Oslo

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
QPM, IBM
Shell model
Single 2 + MSS of 132 Te, 134 Xe, 136 Ba
What is the predictive power?
• QPM: single 2 + MSS of 140 Nd
• SM: fragmented 2 + MSS of 140 Nd
Fragmented 2 + MSS of 138 Ce
QPM and SM reproduce situation in N=80
Identify and quantitatively study
MSSs of 140 Nd and 142 Sm
C. Bauer, N. Pietralla, et al, TU Darmstadt

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
140 Sm
142 Sm
140 Nd
142 Sm
140 Nd result C. Bauer, et al., Phys. Rev. C in press

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
N=80 Isotone: 140 Nd and 142 Sm
82
50

1h
11/2
3s
1/2
2d
3/2
2d
5/2
1g
7/2 p
82
50
40
35
30
25
20
15
10
5
0
Exp. data
New measurement
QPM
LSSM
50 52 54 56
Proton number Z
58 comparison with
• quasi-particle phonon calculations ( N. Lo Iudice et al., PRC 77, 044310 (2008))
• large-scale shell model calculations ( D. Bianco et al., PRC 85, 034332 (2012))
60 62

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
Shape coexistence
Generalized seniority
Change in nuclear structure in neutron deficient Po isotopes
Laser spectroscopy at ISOLDE
( π1h9/2) 2
A.M. Oros et al NPA 645:107 (1999)
R. Julin et al JPG 27:R109 (2001)
T.E. Cocolios et al. PRL 106:052503 (2011)
Transition expected around 200 Po
N. Kesteloot, et al., Univ. of Leuven

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
196,198,200,202
N. Kesteloot, et al., Univ. of Leuven
463 keV
196 Po
2 +  0 + 196 Po
556 keV
2 +  0 + 104 Pd
605 keV
2 +  0 + 198 Po
198 Po
871 keV
2 +  0 + 94 Mo
200 Po
666 keV
2 + 
0 + 200 Po
677 keV
2 + 
0 + 202 Po
202 Po

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
224
120
L.P. Gaffney, P. A. Butler, M. Scheck, A. B. Hayes, F. Wenander, et al.,
Nature 497, 199-204 (2013) doi:10.1038/nature12073
-Heaviest
REX-ISOLDE beam
- B(E3, 0 + ↦ 3 )

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
‘For a NR system made up of point, charged particles which interact electro-statically with each other and with an arbitrary external field, the shielding is complete.’
L.I. Schiff, Phys. Rev. 132 (1963) 2194
Theoreticians search for loopholes in:
• relativistic effects (electron)
• finite-size effects of nucleus can break the symmetry (nucleus)
• magnetic interactions (electron–nucleus)
• non-EM exotica in electron-nucleon interaction
Nuclear pear-shapes can enhance the “Schiff moment” by ~ 3 orders of magnitude
Search candidates are oddA Rn (TRIUMF) and Ra (ANL, ISOLDE)

Outline Physics case MINIBALL@REX-ISOLDE Coulomb excitation - Perspectives
Kα
1,
Kα
2
↓
Kβ
1
↓
223.5 keV
7/2+, 0 keV
223.5
↓
201.0
↓
289.3
↓
22.5 keV
221 Rn, 6x10 3 ion/s
30 hour beam time
120 Sn target, 2 mg/cm 2
George O’Neill, et al., University of Liverpool

Outline Physics case MINIBALL@REX-ISOLDE
Perspectives
Si detector in backwards geometry
Allows conversion electron spectroscopy – complete picture

Outline
-
Physics case
- MINIBALL@REX-ISOLDE
- Perspectives
The MINIBALL T-REX setup
T-REX: Si detector array for Transfer experiments at REX-ISOLDE
• large solid angle (58% of 4 π )
• position sensitive
• PID (ΔE-E): p, d, t, α,
… and e from β-decay (!)
Technical details:
Barrel: 140 mm ΔE / 16 resistive strips
1000 mm E / pad
Backward CD: 500 mm ΔE / DSSSD
500 mm E / pad
V. Bildstein, K. Wimmer,
Th. Kröll, R. Gernhäuser et al.
(funded by TU München,
KU Leuven, U Edinburgh, CSNSM
Orsay, TU Darmstadt)
RIB

Outline Physics case MINIBALL@REX-ISOLDE Transfer reaction - Perspectives d( 66 Ni, 67 Ni)p – the 68 Ni region (N=40)
J. Diriken, P. van Duppen, R. Raabe, et al.; IKS-KU Leuven for the IS469 collaboration

Outline Physics case MINIBALL@REX-ISOLDE Transfer reaction - Perspectives d( 66 Ni, 67 Ni)p – the 68 Ni region (N=40)
• proton gated g
-spectrum
• g
-transitions up to 5800 keV
• pg
g coincidence analysis
• pg prompt
g delayed analysis
High resolution of MINIBALL allows to resolve states and to analyse angular distribution
J. Diriken, et al.; PRL submitted

Outline Physics case MINIBALL@REX-ISOLDE Transfer reaction - Perspectives d( 66 Ni, 67 Ni)p – the 68 Ni region (N=40)
 p -1
1/2
 g
9/2
 d
5/2
 d
5/2
Partial level scheme,17 levels identified and characterized
J. Diriken, et al.; PRL submitted

S. Bottoni, S. Leoni, et al.;
INFN -,Uni. Milano for the IS536 collaboration

Outline Physics case MINIBALL@REX-ISOLDE - Island of Inversion
Perspectives
1.2
MeV/u
3
MeV/u
5.5
MeV/u
2015
8
MeV/u
10
MeV/u
2016

Outline
-
Physics case
-
MINIBALL@REX-ISOLDE - Island of Inversion - Perspectives
• REX-ISOLDE versatile accelerator
• MINIBALL physics case covers nuclei up to Radium
• First years: Shell model physics
• Recent developments:
- Coulex with isomeric and heavy beams
- transfer reactions & g
-ray spectroscopy
• Major perspective: HIE-ISOLDE l l l l l ll l l l l lll l l l l l l l l l l l l l l l l l