The DESIR facility at SPIRAL2
DESIR: Désintégration, excitation et stockage d’ions radioactifs
(Decay, excitation and storage of radioactive ions)
• Result of a SPIRAL2 workshop in July 2005 on ISOL beams at SPIRAL2:
- Decay spectroscopy:
Maria José Garcià Borge (Madrid)
François Le Blanc (IPN Orsay)
Gerda Neyens (KU Leuven)
Paul Campbell (Manchester)
Dave Lunney (CSNSM)
Oscar Naviliat-Cuncic (LPC Caen
Frank Herfurth (GSI)
- LASER spectroscopy:
- Atom and ion traps:
• Spokes-person:
Bertram Blank
• GANIL liaison:
Jean-Charles Thomas
Bertram Blank, SAC SPIRAL2, 19-20 October 2006
pps
• close to stable beam intensities for exotic nuclei
• much higher intensities than at ISOLDE or Oak Ridge
• not too far from EURISOL intensities
• key nuclei like 78Ni, 100Sn, 132Sn with high intensities
• fusion-evaporation to access high-spin states
pps
Why another ISOL facility?
pps
A
A
Conclusions of the SPIRAL2 Workshop (july 2005):
Low energy RIB
1. A new experimental area of about 1500m2 located at the ground
floor, dedicated to the experiments with low-energy beams from
SPIRAL2 is strongly requested. The new building includes areas for
the experimental equipments, acquisition and control rooms.
2. A High Resolution mass Separator (HRS) with a resolution of
M/M>5000 with a dedicated identification station is absolutely
necessary. A separation scheme Low Resolution mass separator →
RFQ cooler → HRS is proposed.
3. The low energy radioactive beams should be available for experiments
already at the beginning of the operation of SPIRAL 2. The physics
program requires both neutron-rich and neutron-deficient beams.
4. More than one production target – ion source station is required to
ensure flexible schedule and a possibility for fast change of the mass of
radioactive beams.
5. An extension of the current LIRAT beam line in order to take full
advantage of the SPIRAL 1 beams is proposed.
DESIR physics program
 Decay spectroscopy
- decay properties and nuclear structure studies
- particle-particle correlations, cluster emission, GT strength
- exotic shapes, halo nuclei
 Laser spectroscopy
- static properties of nuclei in their ground and isomeric states
- deformation
 Fundamental interactions
- CVC hypothesis, CKM matrix unitarity via 0+  0+ transitions
- exotic interactions (scalar and tensor currents)
- CP (or T) violation with e.g. Radium
 Solid state physics and other applications
SPIRAL 2 LAYOUT
GANIL facility
LIRAT
Production building
DESIR
LINAG
Underground
J.C. Thomas, GANIL
DESIR: Ground-floor
LUMIERE
laser
Paul
trap
MOT
general
purpose
spec
trap
neutrons
buncher
Ion sources
x
Beam handling: methods
Magnetic separation (HRS)
PENNING TRAP
z0
r0
2000
A = 112
Rh (6.8/2.1 s)
N
1500
1000
Ru (1.8 s)
500
0
960120
A. Jokinen, JYFL
960160
f [Hz]
960200
960240
Beam handling: RFQ cooler and buncher
RF
RFQ-cooler:
3 p mm mrad, 0.5 eV, 10 ms, 60 %
D. Lunney et al., CSNSM
Beam handling: Implementation
F. Varenne, GANIL
Summary of decay spectroscopy experiments:
The BESTIOL facility
(BEta decay STudies at the SPIRAL2 IsOL facility)
• Decay studies with halo nuclei
• Clustering studies in light nuclei
• Super-allowed b decays and the standard model of electro-weak interaction
• Angular correlation measurements and standard model of electro-weak interaction
• Cases of astrophysical interest
• New magic numbers
• Transition from Order to Chaos
• Shape coexistence, deformation and Gamow-Teller distribution
• High-spin isomers
• Test of isospin symmetry combined with charge exchange reactions
• Beta-delayed charged-particle emission: e.g. proton-proton correlation
Decay properties of exotic nuclei
 Global
properties
• Short half-lives (10ms)
1916
Rutherford & Wood b [Philos. Mag. 31 (1916) 379]
1963
Barton & Bell identified 25Si as bp emitter
• High Qb values
• Low Sp/n values
b-delayed particle emission
 Very
Selective probe
• Selection rules:
• Fermi:
T=0 ; J=0 ; pf = pi
• Gamow-Teller: T=0±1; J=0±1 ; pf = pi
• Reduced transition probability:
T1 / 2
K
C
ft  f *


2
2 2
2
B.R .
B(F)  B(GT)
G V   GA 
E, 
Level density
Spin, Isospin
b-decay properties
Search for exotic interactions
e+
q n
e
nucleus
• b-n angular correlation
requires to measure the recoil ion + b particle
• within the SM
x : Fermi fraction; r : GT/F mixing ratio
• beyond the SM
 contains quadratic S and T contributions
O. Naviliat-Cuncic et al., LPC Caen
Search for exotic interactions:
Production and preparation of 6He
candidate:
(pure GT transition)
deduce bn angular correlation from measurement of b-recoil
(recoil with very low energies < 1 keV)
6He+
production at SPIRAL
cooling in H2 gas / bunching
trapping/measuring
LIRAT low energy beam line
O. Naviliat-Cuncic et al., LPC Caen
Search for exotic interactions: Setup and first results
• TOF of ions extracted from trap
beta telescope
PM
plastic
scintillator
DSSSD
beam
monitor
mCP
6He+
• first time difference for b-decay
RF ON/OFF
(V-A theory)
10cm
mCP recoil ion detector
O. Naviliat-Cuncic et al., LPC Caen
CVC, CKM, exotic currents: 0+  0+ b decays
= 3073.5 (12) s (1)
3074.4 (12) s
(1,2)
Measurements: - Q value
- T1/2
- branching ratios

Vud0+0+
VusK
= 0.9738(4)
(1)
0.9736(3) (1,2,3)
= 0.2200(23)
(PDG)
0.2254(21) (4)
VubB
= 0.00367(47)

(PDG)
2
2
2
2
V
=
V
+
V
+
V
i ui ud us ub = 0.9967(13)
0.9987(11)
(~ 2 shift)
(1) Towner and Hardy, PRL 94 (2003) 092501, PRC 71 (2005) 055501
(2) Savard et al., PRL 95 (2005) 102501
(3) Marciano & Sirlin, PRL 96 (2006) 032002
(4) E865, KTeV, NA48, KLOE
(PDG) Particle Data Group, S. Eidelman et al., PLB 592 (2004) 1
0+  0+ b decays: Physics output
1. Vud matrix element ( test of unitarity)
2. test of CVC (constancy of Ft0+ 0+ values)
W1 = WL cos - WR sin
W2 = WL sin + WR cos
 = m12 / m22
3. right-handed currents:
-0.0005 <  < 0.0015
Ad 3: Left Right Symm.-models
(90% C.L.)
4. scalar currents:
 CS  CS'
-0.005  Re 
 C
V

(90% CL)

.004
 < 00.011

Ad 4: scalar currents
N. Severijns et al.
0+  0+ b decays: Future studies
• further improve results for “classical” isotopes
• determine Ft-values for new isotopes of interest:
Tz = -1 isotopes:
18Ne, 22Mg, 26Si, 30S, 34Ar, 38Ca, 42Ti
Tz = 0 isotopes:
62Ga, 66As, 70Br, 74Rb, 78Y, 82Nb, 86Tc, 90Rh, 94Ag, 98In
 stronger limits for new physics
 test and improve reliability of isospin corrections
 extend CVC test to higher mass region
 needs:
-
relatively pure beams ( 103 at/s) of ‘classical’ and new 0+  0+ isotopes
-
precision spectroscopy techniques (for t1/2 and BR)
-
Penning traps (mainly for QEC/mass)
Study of GT strength via b-delayed proton decay:
21Mg
Theory
Counts
Experiment
21Mg
Energy (keV)
J.C. Thomas
Mirror symmetry studies
b+ : p → n + e+ + n
b- : n → p + e- + n E.C. : p + e- → n +
n
ft+
ft

ft
ft
-
-1
 = nuc + SCC
n
p
n
p
 Allowed Gamow-Teller transitions
(log(ft)<6)
17 couples of nuclei
46 mirror transitions
Average asymmetry  :
11 (1) % in the 1p shell (A<17)
0 (1) % in the (2s,1d) shell (17<A<40)
J.C. Thomas, J. Giovinazzo et al. (GANIL/CENBG)
 = 4.8 (4) %
Search for p-p correlation in b2p decay
Two possible decay schemes:
• sequential → no angular or energy correlation
• 2He type decay → angular and energy correlation
 pairing correlations, nucleon-nucleon interaction, final-state interactions….
Possible candidates:
22Al, 23Si, 26P, 27S, 31Ar, 35Ca, 43Cr, 50Ni ….
Setup: Cube-silicium
• 6 DSSSD
• 6 large-area
silicon det.
• g detection
• beam catcher
or fast tape
I. Matea et al., CEN Bordeaux-Gradignan
Study of decay of
31Ar
at SPIRAL/LIRAT
Proton spectrum
• Production rate: 0.5 – 1 31Ar per second
• strong contamination from 33Ar
I. Matea et al., CEN Bordeaux-Gradignan
One- and two-proton emission from isomers:
94Ag
One- and two-proton emission from isomers:
94Ag
Relative energy spectra for p-p
3-body
0.39(4)s
Seq
E p- p 
1.9 keV
Si-Si-gg (92Rh)
I. Muhka, Nature 439 (2006) 298
1
( E1  E 2 - 2 E1 E 2 cos  2 p )
2
LUMIERE:
Laser Utilisation for Measurement and
Ionization of Exotic Radioactive Elements
• Collinear Laser spectroscopy:
- spins
- magnetic moments
- quadrupole moments
- change of charge radii
N=50, N=64, N=82, etc.
• b-NMR spectroscopy:
- nuclear gyromagnetic factor
- quadrupole moment
} for ground and isomeric states
monopole migration of proton and neutron single particle levels around
persistance of N=50 shell gap around 78Ni
persistance of N=82 shell gap beyond 132Sn
• Microwave double resonance in a Paul trap:
- hyperfine anomaly and higher order momenta
(octupole and hexadecapole deformation)
Eu, Cs, Au, Rn, Fr, Ra, Am ….
78Ni
Atomic hyperfine structure
Interaction between an orbital e- (J) and the atomic nucleus (I,mI,QS)
 results in a hyperfine splitting (HFS) of the e- energy levels
3
K(K  1) - I(I  1)J(J  1)
A
4
ΔEHFS  .K  B .
2
2(2I - 1)(2J - 1)I.J
n
J
EHFS
with K  F(F  1) - I(I  1) - J(J  1)
F
 Hyperfine structure constants:
A
μIHe (0)
and B  eQS Vzz (0)
I.J
 Collinear laser spectroscopy: mI/mI ~ 10-2, QS/QS ~ 10-1 for heavy elements
Isotope shift measurements
Frequency shift between atomic transitions in different isotopes of
the same chemical element
 related to the mass and size differences
J2, F2
J1, F1
nA,A’ J2, F
2
n
A, A'
(A' - A)
 (KNMS  KSMS ).
 F. r 2
A.A'
A,A'
J1, F1
 mean square charge radius variations with a precision ~ 10-3
 study of nuclei shape (deformation)
Isotope shift and nuclear moment measurements
178Hf
isomer at Orsay
F. Le Blanc et al.
101Zr
at JYFL
P. Campbell et al.
Isotope shift measurements
 previous experiments:
COMPLIS
N~82
N~104
 onset of deformation at N=82
 shape transition (even-odd staggering)
(slope ↔ rigidity)
 dynamical effects (vibration)
 shape coexistence
F. Le Blanc et al., IPN Orsay
Isotope shift measurements at DESIR
 with I ~ 103-104 pps:
 N~50:
 neutron skin in N > 50 Ge isotopes (neutron star studies)
 deformation in N ≤ 50 Ni isotopes (collectivity vs magicity)
 N~82:
 shape evolution for Z ≤ 50 (Ag, Cd, In, Sn)
 N~64:
 strongly oblate shapes predicted in Rb, Sr and Y for N > 64
 Z~40:
 shape transitions predicted in the Zr region (Mo, Tc, Ru)
 Rare earth elements:
 large deformation and shape transitions predicted (Ba, Nd, Sm)
b-NMR spectroscopy
b-asymmetry in the decay of polarized nuclei in a magnetic field
 Zeeman splitting related to gI and QS
M+I
I
ΔEm,m-1  h.nL B0
M-I
with
nL 
3h.n Q
1
.(3cos2 (θ) - 1)(m  )
4I(2I - 1)
2
gI .mN.B0
h
and
nQ 
e.QS .VZZ
h
 resonant destruction of the polarization (i.e. b-asymmetry) by means
of an additional RF magnetic field
 gI/gI ~ 10-3, QS/QS ~ 10-2
 complementary technique to collinear laser spectroscopy
 suitable for light elements (low QS values)
The physics case for b-NMR on polarized 60 keV beams
 polarized 60 keV beams are obtained using resonant laser excitation.
 with I ≥ 5.103 pps, T½ from 1 ms to 10 s, beam purity > 50 %.
 b-NMR is a sensitive and precise method to measure g-factors and quadrupole
moments of exotic nuclei (ground states, isomers) with lifetimes from 1 ms up
to several seconds.
 combination with hyperfine structure measurements yields a unique determination
of the spin
(e.g. PRL 94, 022501 (2005)).
 Systematic precise measurements of g-factors reveal deviations from ‘normal’
behaviour and provide information on configuration mixing or onset of deformation
(breaking of shell closures).
 N~50: g factor of neutron-rich Ga and Cu isotopes to determine where
the inversion of the pp3/2 and pf5/2 orbitals occurs.
 N~82: g.s. configuration from gI measurements.
The physics case for b-NMR on polarized beams:
nuclear structure towards and beyond
78Ni
Z=40
Kr
Se
Ge
Zn
Evolution of n orbits
from Z=40 to Z=28:
Z=28
Ni
N=40
N=50
Lifetime OK for b-NMR studies
G. Neyens et al., KU Leuven
ground state spins and moments
of 83Ge, 81Zn, 79Ni and
of 81Ge, 79Zn, 77Ni
g-factors can reveal erosion
of N=50 shell closure
Collinear laser spectroscopy and b-NMR
 previous experiments at COLLAPS:
 from the position of hyperfine transitions: spin
assignment and sign of gI for the g.s. of 31Mg
b asymmetry
HFS
31Mg1+
nRF (MHz)
 from b-NMR: precise measurement of |gI|
 strongly deformed intruder Ip = 1/2+ g.s. of 31Mg, G. Neyens et al, PRL 94, 022501 (2005)
 from QS measurements via b-NMR: QS(11Li) > QS(9Li)
 p-n interaction + halo n orbitals, D. Borremans, Ph.D. Thesis, 2004, KU Leuven
R. Neugart et al.
• Building:
Estimated budget
- DESIR hall:
- Basement:
- Crane:
- 20 % overhead:
• HRS:
- RFQ cooler:
- 2 magnets + power supplies:
- pumps, beam lines, diagonstics:
- 20% overhead:
• Beam handling:
- off-line source:
- RFQ cooler/buncher and switch yards:
- Preparation Penning trap:
- in-trap decay detection system:
- 20% overhead:
• Lumière:
- Laser room with infrastructure
- Two lasers (dye + Ar)
- Collinear laser spectroscopy:
- ß-NMR set-up:
- Paul trap set-up:
- 20% overhead:
• Decay spectroscopy:
- Four Germanium detectors:
- Fast timing set-up:
- 4p charged particle array:
- Neutron detection array:
- 20% overhead:
• Fundamental interactions:
- MOT trap:
- in-flight decay setup:
- 20% overhead:
6000 kEuros
3000 kEuros
1000 kEuros
1000 kEuros
1000 kEuros
816 kEuros
150 kEuros
400 kEuros
130 kEuros
136 kEuros
1640 kEuros
60 kEuros
650 kEuros
460 kEuros
195 kEuros
275 kEuros
972 kEuros
150 kEuros
180 kEuros
170 kEuros
160 kEuros
150 kEuros
162 kEuros
2160 kEuros
1225 kEuros
34 kEuros
168 kEuros
400 kEuros
333 kEuros
600 kEuros
350 kEuros
150 kEuros
100 kEuros
• Beam lines:
3600 kEuros
-----------------------------------------------------------------------------------------------------------------------------------------------TOTAL:
15788 kEuros
The DESIR Collaboration
Lynda Achouri, LPC Caen
Alejandro Algora, IFIC Valencia
Jean-Claude Angélique, LPC Caen
Alain Astier, CSNSM Orsay
Georges Audi, CSNSM Orsay
Juha Aysto, University of Jyvaskyla
Dimiter Balabanski, INRNE Sofia
Emmanuel Balanzat, CIRIL Caen
Gilles Ban, LPC Caen
Bertram Blank, CENBG Bordeaux
Klaus Blaum, University Mainz
Maria Jose Garcia Borge, CSIC Madrid
Dorel Bucurescu, NIPNE Bucarest
Apostol Buta, NIPNE Bucarest
Paul Campbell, University Manchester
Grégory Canchel, CENBG Bordeaux
Daniel Cano Ott, CIEMAT Madrid
Joakim Cederkall, ISOLDE-CERN
Fatima Dayras, CSNSM Orsay
Giacomo de Angelis, INFN Legnaro
Pierre Delahaye, ISOLDE-CERN
Jean-Pierre Delaroche, CEA Bruyères
Frank Delaunay, LPC Caen
Isabelle Deloncle, CSNSM Orsay
François de Oliveira Santos, GANIL Caen
Philippe Dessagne, IPHC Strasbourg
Gilbert Dûchene, IPHC Strasburg
Cédric Dossat, DAPNIA Saclay
Dominique Durand, LPC Caen
Serge Franchoo, IPN Orsay
Xavier Fléchard, LPC Caen
Kieran Flanagan, University Leuven
Carole Gaulard, CSNSM Orsay
Bill Gelletly, University of Surrey
Georgi Georgiev, CSNSM Orsay
Omar Gianfrancesco, CSNSM Orsay
Jérôme Giovinazzo, CENBG Bordeaux
Stéphane Grévy, GANIL Caen
Héloise Goutte, CEA Bruyères-le-Chatel
Paul-Henri Heenen, University Brussels
Frank Herfurth, GSI Darmstadt
Jussi Huikari, CENBG Bordeaux
Fadi Ibrahim, IPN Orsay
Ari Jokinen, University Jyväskylä
Andrea Jungclaus, University Madrid
Klaus Jungmann, KVI Gronningen
Swaminathan Kailas, BARC Mumbai
Jürgen Kluge, GSI Darmstadt
Magdalena Kowalska, University Mainz
François Le Blanc, IPN Orsay
Roy Lemmon, CCLRC Daresbury
Marek Lewitowicz, GANIL Caen
Etienne Liénard, LPC Caen
David Lunney, CSNSM Orsay
Miguel Marques, LPC Caen
Ismael Martel, Universidad de Huelva
Iolanda Matea, CENBG Bordeaux
Enrique Minaya-Ramirez, CSNSM Orsay
Iain Moore, University of Jyväskylä
Oscar Naviliat-Cunic, LPC Caen
Florin Negoita, NIPNE Bucarest
Gerda Neyens, University Leuven
C.J.G. Onderwater, KVI Groningen
Nigel Orr, LPC Caen
Dan Pantelica, NIPNE Bucarest
Sophie Péru-Desenfants, CEA Bruyères
Stephane Pietri, University of Surrey
Natalie Pillet, CEA Bruyères-le-Chatel
Natalie Pillet, CEA Bruyères-le-Chatel
Zsolt Podolyak, University of Surrey
Marie-Genevieve Porquet, CSNSM Orsay
Wolfgang Quint, GSI Darmstadt
Paul-Gerhard Reinhard, University of Erlangen
Ernst Roeckl, GSI Darmstadt
Daniel Rodriguez, Universidad de Huelva
Brian Roeder, LPC Caen
Bertra Rubio, University Valencia
Lutz Schweikhard, University Greifswald
Nathal Severijns, University Leuven
Aradhana Shrivastava, BARC Mumbai
Cosimo Signorini, INFN Padova
Gary Simpson, LPSC Grenoble
John Simpson, CCLRC Daresbury
Olivier Sorlin, GANIL Caen
Krunoslav Subotic, University Belgrade
Olof Tengblad, CSIC Madrid
Catherine Thibault, CSNSM Orsay
Jean-Charles Thomas, GANIL Caen
Dragan Toprek, University Belgrade
Piet van Duppen, University Leuven
David Verney, IPN Orsay
Phil Walker, University Surrey
Christine Weber, GSI Darmstadt
L. Willmann, KVI Gronningen
Hans Wilschut, KVI Gronningen
Martin Winkler, GSI Darmstadt
Nicolae Victor Zamfir, NIPNE Bucarest
Summary
• solid physics case
• very promising intensities for exotic nuclei (e.g. fusion-evaporation)
• almost 100 co-authors the « DESIR » LOI
• with its installations a unique facility
• preliminary study of building at CENBG
• study of cooler/buncher and HRS at CSNSM
• installation of collinear laser spectroscopy at ALTO
• to be built it has to be included in « reference solution »
• synergies with FAIR: DESPEC, LASPEC, MATS, NCAP