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The Belgian Research Initiative on eXotic nuclei (BriX)
Piet Van Duppen
Instituut voor Kern- en Stralingsfysica - K.U.Leuven
Belgium
• Introduction
• Nuclear physics research in Belgium
• Research funding
• The “Interuniversity Attraction Poles Program”: historical note
• The BriX network
• “Advanced Research on Exotic Nuclei for Nuclear Physics and
Nuclear Astrophysics”
• Research highlights (experimental part, theory discussed by J.-M. Sparenberg)
• Conclusion and Outlook
K.U. Leuven
• Nuclear physics research in Belgium
Federal laboratory
K.U. Leuven
• Nuclear physics research in Belgium: funding
• Fundamental nuclear physics research funding:
• Federal:
• Regional:
• Universities:
• EU:
K.U. Leuven
“Interuniversity Attraction Poles Program”
• Interuniversity Attraction Poles Program
Period
Partners
Research Activities
1987-1991
U.C.L. – U.L.B. –
K.U.Leuven
-Radioactive beam production
- 6He, 10,11C, 15O, 18F, 18,19Ne
- Resonant laser ionization of exotic nuclei
1992-1996
U.C.L. – U.L.B. –
K.U.Leuven
1997-2001
U.C.L. – U.L.B. –
K.U.Leuven
2002-2006
U.C.L. – U.L.B. –
U.Gent - K.U.Leuven
2007-2011
U.L.B. – U.Gent –
SCK•CEN K.U.Leuven
- New instrumentation
- Laser ion source
- LEDA array (segmented silicon detector)
- MINIBALL (segmented germanium detector array)
- Penning trap for weak interaction studies
- Nuclear astrophysics: exp. and theory (e.g.
13N(p,g))
- Nuclear structure and reactions: experiment
- ground-state properties (moments, charge radii)
- decay studies
- Coulomb excitation
- fusion, fission and transfer reactions
- Nuclear structure and reactions: theory
- Cluster models, few-body approaches, shell-model,
mean-field, symmetry based approaches
K.U. Leuven
- Fundamental interaction studies
The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
• Belgian partners:
•
P. Descouvemont, D. Baye, P.-H. Heenen, J.-M. Sparenberg
•
K. Heyde, C. Wagemans
•
H. Aït Abderrahim, P. Baeten, P. Schuurmans
•
M. Huyse, G. Neyens, N. Severijns, R. Raabe, P. Van Duppen
• International partners:
• GSI (Germany)
• GANIL (France)
• CSNSM (France)
• U.Köln (Germany)
K.U. Leuven
The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
• Facilities
• Species: from neutron beams to radioactive ion beams
• Energy: from ~ rest up to 50 MeV/u
• Half-life: from ms to hours
KVI-Groningen
CRC-Louvain-la-Neuve
GANIL-Caen
GSI-Darmstadt
ISOLDE - CERN
ILL- Grenoble
K.U. Leuven
The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
• Physics
Z=82
Shape coexistence along Z=82
N=50
N=40
N=82
n-induced and beta-delayed fission
Z=50 Nuclear structure along the N=Z line
Fundamental interaction studies
Z
Z=28
Towards 78Ni: shell structure along Z=28 and N=50
N
“Island of inversion around 32Mg”
Structure
20 of light exotic nuclei
K.U. Leuven
Feasibility study for ISOL@MYRRHA
• Louvain-la-Neuve Radioactive Beam Facility
CYCLONE110 cyclotron
• p,d,a and heavy ions
• Radioactive Ion Beams
LISOL gas cell
LISOL - Leuven Isotope Separator On-Line
Sextupole Ion Guide
Exit
hole
Detection
Target
Laser ion source
Cyclotron
beam
Laser System
Ar/He from
gas purifier
Laser ion source
• Thermalisation in a buffer gas cell (500 mbar Ar)
• Resonant laser ionization: Z-selection (isomer)
• Mass separation: A/Q selection
K.U. Leuven
Filament
Laser
beams
[M. Facina,- NIMB 226 (2004) 401]
[Y. Kudryavtsev,- NIMB 204 (2003) 336]
• Wide spectrum of pure radioactive ion beams
• Energy: from ~ rest up to 3 MeV/u
Post accelerated beams:
8,9,11Li, 10-12Be, 10C, 17F,
24-29Na, 28-32Mg, 61,62Mn,
61Fe, 68Ni, 67-71,73Cu,
74,76,78,80Zn, 70Se, 88,92Kr,
96Sr, 108In,106,108,110Sn,
122,124,126Cd,138,140,142,144Xe,
140,142,148Ba,148Pm, 153Sm,
156Eu, 182,184,186,188Hg,
K.U. Leuven
F. Ames et al., Nucl. Instrum. Methods A 538, 17 (2005)
F. Wenander et al., Nucl. Phys. A701, 528 (2002)
O. Kester et al., Nucl. Instrum. Methods B 204, 20 (2003)
The MINIBALL detector array
Miniball
CD – detector
Double sided Si
strip detector
Coulomb excitation
PPAC
REXISOLDE
120Sn
(2.3
mg/cm2)
Transfer reactions
Si barrel detector
München, Köln, Heidelberg,
Darmstadt, Leuven, York, Liverpool,
Daresbury, Strasbourg,...
J. Eberth et al., Prog. Part. Nucl. Phys. 46, 389 (2001)
K.U. Leuven
Beam
monitor
Miniball
Structure of light exotic nuclei:
properties of key states
12
Beta-decay studies by
implantation in a highly
pixelated Si detector
and decay correlations
O
Z
unbound
11N
12N
unbound
11 ms
9C
10C
11C
125 ms
19.3 s
20.4 m
9B
unbound
10B
12C
11B
12B
20.20 ms
9Be 10Be 11Be 12Be
1.6 106 y
13.8 s
23.6 ms
9Li
10Li 11Li 12Li
179 ms
unbound
8.5 ms
unbound
9He 10He
•Calorimetric technique:
• full energy measured
unbound unbound
• low threshold
• high efficiency
• precise normalisation
11Li:
R. Raabe,- PRL 101 (2008) 212501
S. Hyldegaarda,- PLB submitted
6He: R. Raabe,- PRC submitted
8B: analysis in progress
K.U. Leuven
12N, 12B:
•Measured:
6He (LLN), 11Li (TRIUMF) (2n-halos)
12N, 12B (KVI) (3-alpha states in 12C)
8B (KVI) (spectrum of solar neutrinos)
N
Structure of light exotic nuclei: properties of key states
11Li:
deuteron emission - decay of the halo
Theory: U.L.B.
Resonance above (Va) or below threshold (Vb)
Coulomb contribution (VC)
Raabe et al., PRL 101 (2008) 212501
K.U. Leuven
“Island of inversion” around 32Mg
Present status of the “Island of inversion”
as deduced from static and dynamic moments measurements
32
12
K.U. Leuven
Mg20
“Island of inversion” around 32Mg: moment measurements
S
36
Production of Al isotopes at GANIL
 b-NMR on polarized fragment beams
P
35
Si
29
Si
30
Si
31
Si
32
Si
33
Si
34
Si
35
Si
36
Si
37
Al
28
Al
29
Al
30
Al
31
Al
32
Al
33
Al
34
Al
35
Al
36
Mg
27
Mg
28
Mg
29
Mg
30
Mg
31
Mg
32
Mg
33
Mg
34
Mg
35
Na
26
Na
27
Na
28
Na
29
Na
30
Na
31
Na
32
Na
33
Na
34
Ne
25
Ne
26
Ne
27
Ne
28
Ne
29
Ne
30
Ne
32
F
F
F
27
F
29
22
p 18 +
20
F
24
m 25
(m N) 26
16
4,2
I =5/2
0p-0h
g=1.532(2)
g=1.635(2)
exp
4
MCSM
(50% intruder)
3,8
3,6
2p-2h
3,4
10 12 14 16 18 20 22 24 N
K.U. Leuven
Conclusion:
small (<25-30 %) intruder admixture
in the 33Al ground state.
P. Himpe et al., Phys. Lett. B 643 (2006) 257–262
“Island of inversion” around 32Mg: two-neutron transfer reactions
Radioactive beam onto a radioactive target
3H(30Mg,32Mg)1H
MINIBALL germanium detector
Si barrel detector
K.U. Leuven
ISOLDE -Mark
IS470:
Kathrin Wimmer
Huyse
• In-gas-cell laser spectroscopy of 57,59Cu: a sample of spectra
57Cu
m ( Cu ) 
A
199 ms
55Ni 56Ni 57Ni 58
Ni
6.0 d
36 h
55Co
Ahf ( 63Cu )
65Cu
m ( Cu)
63
Z=28
Cu+ + e-
17 h
63Cu
First Ionization Limit
62317.4 cm-1
54Co
2 = 441.6 nm
N=28
209 ms
Ahf ( ACu )
59Cu
4P0
40943.73
1/2
cm-1
F=2
F=1
1 = 244.164 nm
2S
1/2
CuI: ground state
K.U. Leuven
57Cu:
6 ions/s
F=2
F=1
Frequency [GHz]
• In-gas-cell laser spectroscopy of 57,59Cu: results
[K. Minamisono,- PRL 96 (2006) 102501]
K.U. Leuven
Monopole interaction towards 78Ni: Cu (Z=29)
Experiment
N=40
N=40
Theory
N=50
5/2-
3/25/2-
3/2-
g9/2
40
p1/2
f5/2
p3/2
f7/2
28
protons
“monopole interaction”
Z=28
neutrons
S. Franchoo et al., PRL81 (1998) 3100, PRC64 (2001) 054308
N. Smirnova et al., PRC69 (2004) 044306
A. Lisetskiy et al, PRC70 044314 (2004)
Leuven
T. OtsukaK.U.
et al.,
PRL 85 (2005) 232502
n g9/2
Results: the 5/2- states
A = 63 65
67
69
71
73
 at N=40 (69Cu), the 5/2-1 states undergo a
significant loss in collectivity, are of different
character
 the low B(E2; 5/2-  3/2-) value from N=40
onwards indicates that the 5/2- state is
essentially of single-particle character
I. Stefanescu et al., PRL 100, 112502 (2008 )
I. Stefanescu et al., PRL 98, 122701 (2007)
K.U. Leuven
Results: the 1/2- states
A = 63 65
67
69
71
73
 at N=40 (69Cu), 5/2- states undergoes a
significant loss in collectivity, are of different
character
 the low B(E2; 5/2-  3/2-) value from N=40
onwards indicates that the 5/2- state is
essentially of single-particle character
 the proposed 1/2- shows an important
increase in collectivity beyond N=40;
 onset of collectivity related to the filling of
the g9/2 neutron state.
I. Stefanescu et al., PRL 100, 112502 (2008 )
I. Stefanescu et al., PRL 98, 122701 (2007)
K.U. Leuven
Energy systematics in the odd-mass Cu isotopes
9/2+ 2720
9/2+ 2506
2500
9/2+ 2526
9/2+ ~2500
9/2+ 2551
9/2+ 2600
9/2+ 2385
7/2-
2340
2000
7/2- 1871
7/2- 1711
7/27/2- 1482
1500
7/2- 1310
1/2- 1107
5/2- 1116
5/2- 1028
5/2- 914
1000
N=28
500
3/2-
57
29
5/2- 920
1/2- 1170
5/2- 1115
2+(A-1Ni)
0
Cu28
491
3/2-
59
29
0
Cu30
K.U. Leuven
1/2-
3/2-
7/2- 981
61
29
Cu32
3/2-
63
29
0
Cu34
3/2-
65
29
0
Cu36
pf7/2: p(2p-1h)
7/2- 1010
7/2- 961
1/2- 771
475
0
7/2- 1190
1/2- 1096
5/2- 962
1/2- 670
1/2-
5/2- 1213
N=40
pp3/2
?
7/2- 1327
7/2- 1398
1670
3/2-
67
29
0
Cu38
3/2-
69
29
5/2- 534
collective 1/2- state
1/2- 454
0
Cu40
3/2-
71
29
0
Cu42
pp3/2 2+(A-1Ni)
pf5/2
5/2- 166
1/2- 135
3/2- 0
73
29
Cu44
140
65
3/2- 0
75
29
Cu46
Collinear laser spectroscopy on Cu isotopes at ISOLDE
 Ground state spins, magnetic moments, quadrupole moments, charge radii
from 61Cu up to 75Cu !
73Cu,
No hyperfine anomaly
ratio of A-factors = constant
if correct spin used in fit
I=3/2
I=3/2
75Cu,
I=5/2
I=5/2
I=7/2
K.T. Flanagan et al.,
K.U. Leuven
Shape co-existence in the lead region
Mean square charge radii
Potential energy surface
Shape staggering
186Pb
104
Onset of deformation
H. De Witte et al. PRL 98 (2007) 112501
Theory: U.L.B. – U.Gent
K.U. Leuven
A.N. Andreyev et al., Nature 405, 430 (2000)
Shape co-existence in the lead region studied with Coulomb excitation
Coulomb excitation @ 3 MeV/u
184Hg (3 MeV/u) + 112Cd
1089
4+
21  01
367
2+
0
0+
Hg x rays
112

1
Cd

1
4 2
653
534
4+
2+
375
0+
21  01
22  01
Energy (keV)
Nick Bree, Andrew Petts et al.
Sign, magnitude
of deformation
Strongly-coupled
matrix elements
Band mixing
K.U. Leuven
Rare charge-particle decay studies: ISOLDE and GSI
a
EC/b+
A.N. Andreyev et al.
Beta delayed fission
bDF
g
g
g
g
g
g
g
g
g
Bf,i
Bf,e
Spontaneous fission
• Fission of 180Hg observed in the beta decay of 180Tl
• Unexpected asymmetric mass split
(180Hg (Z=80, N=100) = 2 x 90Zr (Z=40, N=50)
• Cold fission, important for the end of the r-process
K.U. Leuven
Study of (n,f) cross section measurements
• Improve data base for transmutation of minor actinides (e.g. 245Cm)
• Ternary fission (e.g. 249Cf):
• improve the understanding of the ternary fission process (a, t)
• important source of helium and tritium gas production in nuclear reactors
• Complementary measurements at different facilities:
• thermal neutrons: high flux reactor at ILL and BR1 reactor at SCK•CEN
• resonance neutrons at TOF facility at IRMM
• FWHM increases with increasing fissility parameter
Z2/A of the compound nucleus:
GELINA (GEel LINear Accelerator)
IRMM Geel (Belgium)
FLIGHT PATHS
NORD
FWHM(SF) < FWHM(n,f): 0.3 MeV difference
(excitation energy broadens)
ELECTRON
LINAC
NEUTRON
TARGET
FLIGHT PATHS
SOUTH
C. Wagemans et al., Nucl. Sci. Engn. 160 (2008) 200
K.U.
S. Vermote
et Leuven
al., Nucl. Phys. A806 (2008) 1
WITCH Penning trap at ISOLDE – Search for scalar weak currents
• Detect recoiling ions in singles for bn angular correlation
• Select ion energies sequentially: retardation potential
First recoil ion spectrum
124Sn
recoils
proof of
principle
demonstrated
Retardation potential (V)
V.Yu. Kozlov et al., NIM B 266 (2008) 4515
S. Coeck et al., NIM A, 574 (2007) 370
system currently being upgraded
and being prepared for
measurement with 35Ar in 11/2009
K.U. Leuven
S. Coeck et al., NIM A 572 (2007) 585
V.Yu. Kozlov et al., Hyp. Int. 172 (2006) 15
V.Yu. Kozlov et al., Int. J. Mass Sp. 251 (2006) 159
S. Coeck et al., NIM A 557 (2006) 516-522
Test of CVC and new value for Vud from T=1/2 mirror decays
nucleus dependent
nucleus indepen
corrected ft-value for
T = 1/2 mirror transitions
:
calculated
from experiment
21Na
29P
19Ne
37K
pion
35Ar
0+→0+
neutron
mirrors
• New value of |Vud| :
|Vud| = 0.9719(17)
• First consistent test of CVC from a
set of nuclear transitions other than
super-allowed pure Fermi
O. Naviliat-Cuncic & N. Severijns, Phys. Rev. Lett. 102 (2009) 142302
N. Severijns, I.S. Towner et al., Phys. Rev. C 78 (2008) 055501
K.U.
Leuven
N. Severijns
et al.,
Rev. Mod. Phys. 78 (2006) 991
Fundamental physics with neutrons at PSI: neutron electric dipole moment (nEDM)
- Standaard Model value for dn  10-32 e cm
(from observed CP-violation in K- and B-meson decays)
- observation of nEDM with larger value would point to
NEW source of CP-violation;
- could explain matter-antimatter asymmetry in the Universe
- present limit | dn | < 2.9 x 10-26 e cm
( C.A. Baker et al., Phys. Rev. Lett. 97
(2006) 131801 )
- several extensions of the Standaard Model predict values for
dn in the range 10-26  10-28 e cm
- present goal: | dn | < 5 x 10-28 e cm
( by ~ 2015 ; 4 experiments )

S. Roccia et al., Phys. Rev. Lett., submitted
A. Knecht et al., Phys. Rev. Lett. , submitted
Leuven
K. Kirch et K.U.
al., NIM
A (2009) in print
• Conclusion
• Belgian experimental nuclear physics activities under the BriX network:
• Radioactive beam production and use (from rest to 50 MeV/u)
• Broad spectrum of instrumentation, tools and techniques:
• Lasers, arrays of segmented Ge and Si detectors, Penning traps
• Moment and charge radii measurements, decay studies, Coulomb
excitation, transfer reactions
• Physics:
• Nuclear-structure, nuclear reaction and fundamental interaction studies
using neutrons and exotic nuclei
K.U. Leuven
• Outlook short and intermediate term
ENERGY:
Energy upgrade to 10 MeV/u and lower energy capacity
INTENSITY: ISOLDE proton driver beam intensity upgrade
strongly linked to PS Booster improvements including linac4
QUALITY: ISOLDE radioactive ion beam quality: broader spectrum and
higher quality (purity, emittance, time structure) and isomeric beams
• Installation and use of the LISOL gas cell based laser ion source at the focal plane of
the S3 project (intense heavy-ion beams, production of pure secondary beams, laser
spectrocospy)
• Participation in DESIR (laser spectroscopy)
European Separator On-Line
Radioactive Nuclear Beam Facility
K.U. Leuven
• Outlook long term
Nuclear Physics Research at the MYRRHA accelerator at SCK•CEN
• 600 MeV, 100-200 mA, D.C. proton beam (from the initial 2.5 mA for MYRRHA)
• Different target materials including uranium (e.g. UC: workhorse targets at present)
• Ruggedized target-ion source systems that deliver RIB @ ~50 keV:
• ECR 1+: gaseous elements (noble gases, C, N, O,..))
• Surface ion source (hot cavity): alkaline and earth alkaline elements
• Laser ion sources
MYRRHA
accelerator
ISOL target 1+ ion source
1+ low-resolution
separator
• In the field of fundamental interaction studies, nuclear physics, atomic
experiment
• Long beam times (e.g. 12 weeks) for experiments that:
• need very high statistics
• involve many time consuming systematic measurements
• hunt for very weak signals
• have an inherent low-detection efficiency
1+ high-resolution
separator
physics, condensed matter research,…
• Isol@myrrha is complementary to other ISOL facilities and will be an integral part of the MYRRHA
project K.U.
(seeLeuven
talk H. Aït Abderrahim)
• Outlook 2011
• Organization of the joined RNB-ENAM conference in 2011 in Leuven
Everybody is cordially invited.
Thank you for your attention
K.U. Leuven
50
llllllllll
1g9/2
• Coulex (up to 68Ni, 73Cu, 80Zn)
• Decay studies
• Laser spectroscopy studies
40
40
2p1/2
ll
1f5/2
2p3/2
J. Van de Walle et al., PRL 99, 142501 (2007)
J. Van de Walle et al., PRC 79, 014309 (2009)
I. Stefanescu et al., PRL 100, 112502 (2008 )
I. Stefanescu et al., PRL 98, 122701 (2007)
1f7/2
N=40
f5/2
50
llllll
llll
28
28
llllllll
llllllll
sd-shell
sd-shell
p
N=50
 Evolution towards 78Ni along N=50
 Onset of deformation Z>28
n
78Ni
p1/2
g9/2
68
28
K.U. Leuven
Ni 40
Z=28
78
28
Ni50
N=50 isotones
Ni,Zn,Ge isotopes
Ge
Zn
Ni
Neutron Number
K.U. Leuven
B(E2,2+10+1) [W.u.]
B(E2,2+10+1) [W.u.]
E(2+1) [keV]
E(2+1) [keV]
this work
Proton Number
B(E2,2+10+1) [W.u.]
B(E2,2+10+1) [W.u.]
E(2+1) [keV]
E(2+1) [keV]
Zn isotopes
Shell Model (1) 56Ni core :
M. H. Jensen + monopole adjusted by Nowacki N=50 isotones
(ep,en)=(1.9e,0.9e) - (U.Gent - N. Smirnova et al, 2006)
Zn
K.U. Leuven
Neutron Number
Proton Number