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K.U. Leuven
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
• Fundamental nuclear physics research funding:
• Federal: “Interuniversity Attraction Poles Program”
• Regional:
• Universities:
• EU:
• Nuclear physics research in Belgium: funding
K.U. Leuven
• Interuniversity Attraction Poles Program
Period Partners Research Activities
1987-1991 U.C.L. – U.L.B. – K.U.Leuven
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
Nuc
lear
Str
uctu
re
Nuc
lear
Ast
roph
ysic
s
-Radioactive beam production- 6He, 10,11C, 15O, 18F, 18,19Ne- Resonant laser ionization of exotic nuclei
- 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
- Fundamental interaction studies
K.U. Leuven
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
ISOLDE - CERN
GSI-DarmstadtGANIL-Caen
KVI-Groningen
CRC-Louvain-la-Neuve
The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
ILL- Grenoble
• Facilities
• Species: from neutron beams to radioactive ion beams• Energy: from ~ rest up to 50 MeV/u• Half-life: from ms to hours
K.U. Leuven
Z=28
Z=50
N=4
0Z=82
20
N=5
0
N=8
2
N
Z
Structure of light exotic nuclei
Towards 78Ni: shell structure along Z=28 and N=50
Shape coexistence along Z=82
Nuclear structure along the N=Z line
Fundamental interaction studies
n-induced and beta-delayed fission
The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
Feasibility study for ISOL@MYRRHA“Island of inversion around 32Mg”
• Physics
K.U. Leuven
Laser ion source
LISOL - Leuven Isotope Separator On-Line
• Louvain-la-Neuve Radioactive Beam Facility
LISOL gas cell
Laser beams
Target
Cyclotron beam
Exit hole
Sextupole Ion Guide
Ar/He from gas purifier
Filament
CYCLONE110 cyclotron• p,d,a and heavy ions• Radioactive Ion Beams
Laser System
Detection
Laser ion source• Thermalisation in a buffer gas cell (500 mbar Ar)• Resonant laser ionization: Z-selection (isomer)• Mass separation: A/Q selection
[M. Facina,- NIMB 226 (2004) 401][Y. Kudryavtsev,- NIMB 204 (2003) 336]
K.U. Leuven
• 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, 202,204Rn
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)
K.U. Leuven
München, Köln, Heidelberg, Darmstadt, Leuven, York, Liverpool,
Daresbury, Strasbourg,...
The MINIBALL detector array
J. Eberth et al., Prog. Part. Nucl. Phys. 46, 389 (2001)
Miniball
120Sn
REX-ISOLDE
PPAC
Beammonitor
CD – detectorDouble sided Si strip detector
(2.3 mg/cm2)
Coulomb excitation
Si barrel detector
Miniball
Transfer reactions
K.U. Leuven
9Heunbound
10Heunbound
9Li179 ms
10Liunbound
12Be23.6 ms
9Bunbound
10B 11B12B
20.20 ms
12Liunbound
9C125 ms
10C19.3 s
11C20.4 m
11Li8.5 ms
9Be10Be1.6 106 y
11Be13.8 s
12C
12N11 ms
11Nunbound
12Ounbound
N
ZStructure of light exotic nuclei: properties of key states
Beta-decay studies by implantation in a highly pixelated Si detectorand decay correlations
•Calorimetric technique:• full energy measured• low threshold• high efficiency• precise normalisation
•Measured:6He (LLN), 11Li (TRIUMF) (2n-halos)12N, 12B (KVI) (3-alpha states in 12C)8B (KVI) (spectrum of solar neutrinos)
11Li: R. Raabe,- PRL 101 (2008) 21250112N, 12B: S. Hyldegaarda,- PLB submitted6He: R. Raabe,- PRC submitted8B: analysis in progress
K.U. Leuven
11Li: deuteron emission - decay of the halo
Theory: U.L.B.
Raabe et al., PRL 101 (2008) 212501
Structure of light exotic nuclei: properties of key states
Resonance above (Va) or below threshold (Vb)Coulomb contribution (VC)
K.U. Leuven
Present status of the “Island of inversion”as deduced from static and dynamic moments measurements
“Island of inversion” around 32Mg
3212 20Mg
K.U. Leuven
Si29
Si30
Si31
Si32
Si33
Si34
Si35
Si36
Si37
Al28
Al29
Al30
Al31
Al32
Al33
Al34
Al35
Al36
Mg27
Mg28
Mg29
Mg30
Mg31
Mg32
Mg33
Mg34
Mg35
Na26
Na27
Na28
Na29
Na30
Na31
Na32
Na33
Na34
Ne25
Ne26
Ne27
Ne28
Ne29
Ne30
Ne32
F24
F25
F26
F27
F29 22
201816
P35
S36 Production of Al isotopes at GANIL
b-NMR on polarized fragment beams
g=1.532(2)
g=1.635(2)
P. Himpe et al., Phys. Lett. B 643 (2006) 257–262
Conclusion:small (<25-30 %) intruder admixture in the 33Al ground state.
3,4
3,6
3,8
4
4,2
10 12 14 16 18 20 22 24 N
m (mN) 0p-0h
exp
MCSM(50% intruder)
2p-2h
Ip=5/2+
“Island of inversion” around 32Mg: moment measurements
K.U. Leuven Mark Huyse
“Island of inversion” around 32Mg: two-neutron transfer reactionsRadioactive beam onto a radioactive target
3H(30Mg,32Mg)1H
Si barrel detector
MINIBALL germanium detector
ISOLDE - IS470: Kathrin Wimmer
K.U. Leuven
First Ionization Limit62317.4 cm-1
CuI: ground state
Cu+ + e-
1 = 244.164 nm
2 = 441.6 nm
40943.73 cm-1
2S1/2
4P01/2
65Cu
63Cu
59Cu
57Cu: 6 ions/s
Frequency [GHz]
F=1
F=2
F=2F=1
6363
( )( ) ( )
( )
AhfA
hf
A CuCu Cu
A Cum m
56Ni6.0 d
57Cu199 ms
54Co
55Ni209 ms
55Co17 h
57Ni36 h
58Ni Z=28
N=
28
• In-gas-cell laser spectroscopy of 57,59Cu: a sample of spectra
K.U. Leuven
• In-gas-cell laser spectroscopy of 57,59Cu: results
[K. Minamisono,- PRL 96 (2006) 102501]
K.U. Leuven
5/2-
3/2-5/2-
3/2-
N=40 N=40 N=50
S. Franchoo et al., PRL81 (1998) 3100, PRC64 (2001) 054308N. Smirnova et al., PRC69 (2004) 044306A. Lisetskiy et al, PRC70 044314 (2004)T. Otsuka et al., PRL 85 (2005) 232502
Experiment Theory
28
neutronsprotons
g9/2
f7/2
f5/2
40
p3/2
p1/2
“monopole interaction”
n g9/2
Z=28
Monopole interaction towards 78Ni: Cu (Z=29)
K.U. Leuven
A = 63 65 67 69 71 73
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
Results: the 5/2- states
at N=40 (69Cu), the 5/2-1 states undergo a
significant loss in collectivity, are of different character
I. Stefanescu et al., PRL 100, 112502 (2008 )I. Stefanescu et al., PRL 98, 122701 (2007)
K.U. Leuven
A = 63 65 67 69 71 73
onset of collectivity related to the filling of the g9/2 neutron state.
the proposed 1/2- shows an important increase in collectivity beyond N=40;
Results: the 1/2- states
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
at N=40 (69Cu), 5/2- states undergoes a significant loss in collectivity, are of different character
I. Stefanescu et al., PRL 100, 112502 (2008 )I. Stefanescu et al., PRL 98, 122701 (2007)
K.U. Leuven
3/2- 0
7529 46Cu73
29 44Cu7129 42Cu69
29 40Cu6729 38Cu65
29 36Cu6329 34Cu61
29 32Cu5929 30Cu57
29 28Cu
3/2- 0 3/2- 0 3/2- 0 3/2- 0 3/2- 0 3/2- 0 3/2- 0 3/2- 0 3/2- 0
5/2- 1028
1/2- 1107
1/2- 491
5/2- 914 5/2- 920
1/2- 475
1/2- 670
5/2- 962
5/2- 11161/2- 11705/2- 1115 1/2- 1096
5/2- 1213
7/2- 1670
9/2+ 2551
500
1000
1500
2000
25009/2+ ~25009/2+ 25269/2+ 2506
9/2+ 2720
7/2- 1871
1/2- 454
5/2- 534
7/2- 1190
7/2- 961
9/2+ 2600
5/2- 1661/2- 135
9/2+ 2385
1/2- 771
140 65
7/2- 2340
7/2- 1711
7/2- 981 7/2- 1010
7/2- 1482
7/2- 1327
7/2- 13107/2- 1398
pf5/2
pp3/2 2+(A-1Ni)
pf7/2: p(2p-1h)
N=40
N=28
Energy systematics in the odd-mass Cu isotopes
?
collective 1/2- state
pp3/2 2+(A-1Ni)
K.U. Leuven
Ground state spins, magnetic moments, quadrupole moments, charge radii
from 61Cu up to 75Cu !
73Cu, I=3/2
75Cu, I=5/2
No hyperfine anomalyratio of A-factors = constant
if correct spin used in fit
I=5/2
I=7/2
I=3/2
K.T. Flanagan et al.,
Collinear laser spectroscopy on Cu isotopes at ISOLDE
K.U. Leuven
Shape co-existence in the lead region
H. De Witte et al. PRL 98 (2007) 112501
Shape staggering
Onset of deformation
Mean square charge radii
A.N. Andreyev et al., Nature 405, 430 (2000)
186Pb104
Potential energy surface
Theory: U.L.B. – U.Gent
K.U. Leuven
Strongly-coupledmatrix elements
Band mixing
Sign, magnitude of deformation
Shape co-existence in the lead region studied with Coulomb excitation
1 12 0
1 14 2
2 12 0
1121 12 0Cd
Hg x rays
Nick Bree, Andrew Petts et al.
0+
2+
4+
0+
2+4+
0
367
1089
375
534653
Energy (keV)
Coulomb excitation @ 3 MeV/u184Hg (3 MeV/u) + 112Cd
K.U. Leuven
Bf,i Bf,e
Spontaneous fission
EC/b+
bDF
g
ggg
g
g
g
gg
aA.N. Andreyev et al.
Rare charge-particle decay studies: ISOLDE and GSI
• 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
Beta delayed fission
K.U. Leuven
Study of (n,f) cross section measurements
• FWHM increases with increasing fissility parameter Z2/A of the compound nucleus:
FWHM(SF) < FWHM(n,f): 0.3 MeV difference (excitation energy broadens)
• 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
C. Wagemans et al., Nucl. Sci. Engn. 160 (2008) 200 S. Vermote et al., Nucl. Phys. A806 (2008) 1
• 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
FLIGHT PATHSSOUTH
NEUTRONTARGET
ELECTRONLINAC
FLIGHT PATHSNORD
GELINA (GEel LINear Accelerator)IRMM Geel (Belgium)
K.U. Leuven
• Detect recoiling ions in singles for bn angular correlation• Select ion energies sequentially: retardation potential
First recoil ion spectrum
Preliminary
Retardation potential (V)
124Sn recoils
proof of principle
demonstrated
system currently being upgradedand being prepared for
measurement with 35Ar in 11/2009
V.Yu. Kozlov et al., NIM B 266 (2008) 4515
S. Coeck et al., NIM A, 574 (2007) 370
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
WITCH Penning trap at ISOLDE – Search for scalar weak currents
K.U. Leuven
O. Naviliat-Cuncic & N. Severijns, Phys. Rev. Lett. 102 (2009) 142302
N. Severijns, I.S. Towner et al., Phys. Rev. C 78 (2008) 055501
N. Severijns et al., Rev. Mod. Phys. 78 (2006) 991
corrected ft-value for T = 1/2 mirror transitions
:
calculated from experiment
nucleus dependent nucleus independent
29P
19Ne
21Na37K
35Ar
• New value of |Vud| :
|Vud| = 0.9719(17)
0+→0+
neutron
pion
mirrors
• First consistent test of CVC from a set of nuclear transitions other than super-allowed pure Fermi
Test of CVC and new value for Vud from T=1/2 mirror decays
K.U. Leuven
S. Roccia et al., Phys. Rev. Lett., submitted
A. Knecht et al., Phys. Rev. Lett. , submitted
K. Kirch et al., NIM A (2009) in print
- present goal: | dn | < 5 x 10-28 e cm ( by ~ 2015 ; 4 experiments )
- several extensions of the Standaard Model predict values for dn in the range 10-26 10-28 e cm
- present limit | dn | < 2.9 x 10-26 e cm ( C.A. Baker et al., Phys. Rev. Lett. 97 (2006) 131801 )
- 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
Fundamental physics with neutrons at PSI: neutron electric dipole moment (nEDM)
K.U. Leuven
• 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
• 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)
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
European Separator On-LineRadioactive Nuclear Beam Facility
K.U. Leuven
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
• 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
• Outlook long term
ISOL target 1+ ion source
RF
-cooler
1+ low-resolution separator
1+ high-resolution separator
experiment
MYRRHAaccelerator
• In the field of fundamental interaction studies, nuclear physics, atomic physics, condensed matter research,…
• Isol@myrrha is complementary to other ISOL facilities and will be an integral part of the MYRRHA project (see talk H. Aït Abderrahim)
K.U. Leuven
Thank you for your attention
• Organization of the joined RNB-ENAM conference in 2011 in Leuven
Everybody is cordially invited.
• Outlook 2011
K.U. Leuven
N=5
0
Z=28
N=4
0
llllllll
28
50
40
llll
llllll
n
ll
llllllllll
sd-shell
1f7/2llllllll
2p1/2
1f5/2
2p3/2
sd-shell
28
50
1g9/2
40
p78Ni
p1/2 g9/2f5/2
Ni68
28 40 Ni78
28 50
Evolution towards 78Ni along N=50 Onset of deformation Z>28
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)
• Coulex (up to 68Ni, 73Cu, 80Zn)• Decay studies• Laser spectroscopy studies
K.U. Leuven
Proton NumberNeutron Number
Ni
Zn
Ge
N=50 isotones
B(E2
,2+ 1
0+ 1) [W
.u.]
E(2+ 1)
[keV
]
B(E2
,2+ 1
0+ 1) [W
.u.]
E(2+ 1)
[keV
]Ni,Zn,Ge isotopes
this work
K.U. Leuven Proton NumberNeutron Number
Zn
N=50 isotones
B(E2
,2+ 1
0+ 1) [W
.u.]
E(2+ 1)
[keV
]
B(E2
,2+ 1
0+ 1) [W
.u.]
E(2+ 1)
[keV
]
Zn isotopesShell Model (1) 56Ni core :
M. H. Jensen + monopole adjusted by Nowacki(ep,en)=(1.9e,0.9e) - (U.Gent - N. Smirnova et al, 2006)