Thomas Nilsson, CERN EP/IS
Exotic Nuclei and Radioactive Beams at Low EnergyExotic Nuclei and Radioactive Beams at Low EnergyEPS-12 Trends in Physics, Budapest August 29 2002
Exotic Nuclei and Radioactive Beams at Low EnergyExotic Nuclei and Radioactive Beams at Low EnergyEPS-12 Trends in Physics, Budapest August 29 2002
•Radioactive beams•Rationale•Production - separation
•CERN-ISOLDE•Research on nuclei at the driplines•Interdisciplinary uses of RIB•REX-ISOLDE
•Outlook•ISOLDE-RNB•EURISOL
Why study the atomic nucleus? A few-body system of
hadrons (neutrons and protons) with many remaining question marks
“Largest” system where strong and weak interaction are manifested
“Applications”– Astrophysics– Condensed matter– Energy– Medicine
Nuclear chart
N = Z
?
Research with Radioactive Ion Beams
Nuclear PhysicsNuclear Decay
Spectroscopy and Reactions
Structure of NucleiExotic Decay Modes
Atomic Physics
Laser Spectroscopy and Direct Mass MeasurementsRadii, Moments, Nuclear Binding
Energies
Nuclear Astrophysics
Dedicated Nuclear Decay/Reaction Studies
Element Synthesis, Solar Processes
f(N,Z)
Fundamental Physics
Direct Mass Measurements, Dedicated Decay Studies - WICKM unitarity tests, search for - correlations, right-handed
currents
Applied Physics
Implanted Radioactive Probes, Tailored Isotopes
for Diagnosis and Therapy
Condensed matter physics and Life sciences
RIB - Production reactions
Spallation Fragmentation Fission
– n- (thermal or energetic), p-induced– Photofission (e-beam)
1 GeV p
p n
2 3 8
U
2 0 1
F r
+ spallation
1 1
L i X
+ + fragmentation
1 4 3
C s Y
+ + fission
Radioactive beams – production and separation
1 GeV
1 MeV
1 keV
1 eV
fragmentation (FRS)
deceleration cooling(storage rings)
post-acceleration
isotope separationon-line (ISOL)
E/A
target-ion source
In-flight production (e.g. FRS@GSI)
1 GeV/u U
ISOL (e.g. ISOLDE@CERN)
ISOL target
Resonant LASER Ion Source
Nuclear chart@ISOLDE
RIB facilities worldwide
SpinsMomentsSpins
Moments
Elastic ScatteringElastic
Scattering
MomentumDistributions
MomentumDistributions
ReactionCross Sections
ReactionCross Sections
BetaDecayBeta
Decay
UnboundNuclei
UnboundNuclei
Experimental Studies of Dripline Nuclei
MassesMasses
Halo nuclei at ISOLDE
8 104 s-1
3 107 s-1
7 106 s-1
1 104 s-1
3 101 s-1
Measurement of the Magnetic Moment of 11Be
11Be
The large radius of 11Be: halo structure or deformation?
I(11Be) = -1.682(3) N
Comparison to theoretical approaches
-1.5 N < I(11Be) < -1.6 N
for: strong small degrees of deformation
Result indicates a rather pure halo structure with hardly any additional deformation
7.82 7.83 7.84 7.85 7.86 7.87 7.88
0.7%
0.8%
0.9%
1.0%
1.1%
1.2%
-asy
mm
etry
frequency [MHz]
W. Geithner et al., PRL 83 (1999) 3793
Young93(reaction)
Wouters88(TOFI)
Kobayashi91(reaction)
Thibault75(mass spec.)
100
150
200
250
300
350
400
450
11Li
tw
o-ne
utro
n se
para
tion
ener
gy (
keV
)mass measurements of 11Li
AME95303 ± 27 keV
D. Lunney
= /(2S2n)1/2
Mass measurement of 11Li at ISOLDE with MISTRAL
RF
B AME: S2n = 303 ± 27 keV
Mistral shouldachieve < 20 keV
D. Lunney
RF
ion counting
referenceion source
1 m
magnet(22 T)
slit 0.4 mm
11Li
11Be10Be+n
9Be+2n
8Be+3n
8Li+t
9Li+d
20.6
0.320 0.504
7.315
8.982
17.916
15.721
(MeV)
3/2-
10.59
8.82
Open delayed-particle channels in the 11Li beta decay
Open delayed-particle channels in the 11Li beta decay
L i11
e-
Qd = 3.004 –S2n MeV
T. Nilsson, G. Nyman, K. Riisager HFI 129(2000)67
11Be
0.320
½+
½-
10Be (1n recoils)
Tritons+deuterons
11Li 11Be* x+y
E, gas
E, Si
11Li, charged particles
20.6
6He+n7.91
11Li3/2-
10Be + n11Be
0.503
-
18.15
9Be + 2n7.32
9Li + d
17.9
8Li + t15.7
8.90
3n
½-
½+E(MeV)
0 5 10 15 20
BG
T/M
eV
1
2
11Li
11Li
M.J.G. Borge et al, PRC 55 (1997) R8
I.Mukha et al., PL B367 (1996) 65
M.J.G. Borge et al.. Nucl. Phys. A613 (1997) 199
Beta-strength function
14Be
ISOLDE Physics programme 2001
0 10 20 30 403000
3100
3200
0 10 20 30 402000
2500
3000
3500
4000
Ft
Z of daughter
74Rb
Ft
Z of daughter
Systematics of the superallowed transitionsI. S. Towner and J.C. Hardy,Proc. 5th Int. Symp. on Weak and Electromagnetic Interactions in Nuclei: WEIN'98, 14.-21.6.1998, Santa Fe, (1998) and this work (2001).
corr. Coulomb
corr. radiative dep. nuc.
corr. radiative ind. nuc.
C
R
R
)1(2)1)(1(
2RV
CR G
KFtft
valueQ halflife
Superallowed Fermi transitions
Test of CVC (Conserved Vector Current) hypothesis
1,00 T
udV of det.Best
2VG
Kft
CKM (Cabibbo-Kobayashi-Maskawa) matrix unitarity
0014.09968.0 :Exp.
1 :SM2
ub
2
us
2
ud
2
ub
2
us
2
ud
VVV
VVV
unitarity is violated by 2.2
corr. Coloumb
corr. radiative dep. nuc.
corr. radiative ind. nuc.
C
R
R
)1(2)1)(1(
2RV
CR G
KFtft
0 10 20 30 403000
3100
3200
0 10 20 30 402000
2500
3000
3500
4000
Ft
Z of daughter
74Rb
Ft
Z of daughter
New physics or bad corrections? Test at extreme -> 74Rb
… and later 62Ga
1230060 1230080 1230100 1230120 1230140 1230160 123018080
120
160
200
240
280
320
360
TO
F(
s)
c(Hz)270460 270465 270470 270475 270480
0
5
10
15
20
num
ber
of io
ns
frequency (kHz)
MIS RALISOLTRAP
IS384 Complete spectroscopy on Fermi -emitter 74Rb
Results:1) non-analog 0+ 0+ transition observed estimate for the Coulomb mixing2) mass of 74Rb (ISOLTRAP & MISTRAL)3) mass of the daughter 74Kr (ISOLTRAP)
2) & 3) QEC value
T1/2 = 64.9 ms!
460 480 500 520 540
100
200
300
0+
508 - 0+
g.s. E0 transition
cts/
chenergy(keV)
0+ <0.07%
Radioactive ions as “spies” (PAC) in high-Tc superconductors…
… or as dopants in semiconductors that change with time.
Condensed matter physics
M. Deicher, Europhysics News (2002) Vol. 33 No. 3
Biomedical Research at ISOLDE
Example: samarium isotopes
in vivo dosimetry by positron emission tomography (PET)
142-Sm (, T1/2 = 72m) 142-Pm (, T1/2 = 40s)
therapy 153-Sm ( , T1/2 = 47h)
PET scan of a rabbit 60 min p.i. of ISOLDE produced
142-Sm in EDTMP solution
Future tool?
IS393 - Nuclear properties in r-process vicinity
Post-acceleration
1 GeV
1 MeV
1 keV
1 eV
fragmentation (FRS)
deceleration cooling(storage rings)
post-acceleration
isotope separationon-line (ISOL)
E/A
target-ion source
REX-ISOLDE
E
Accumulation Cooling Ejection
d(9Li,10Li*)p using REX-ISOLDE
0 keV200
400
600
800
1000
Eex(10Li) =
A second-generation RIB facility at CERN? – ISOLDE-RNB
H- RFQ1 chop. RFQ2RFQ1 chop. RFQ2 RFQ1 chop. RFQ2DTL SCDTL RFQ1 chop. RFQ2 0.52 0.7 0.8 LEP-II dump
Source Low Energy section DTL Superconducting low-
45 keV 7 MeV 120 MeV 1.08 GeV 2.2 GeV
2 MeV 18MeV 237MeV 389MeV
10m 78m 334m 357m
PS / Isolde
Stretching andcollimation line
Accumulator Ring
Superconducting 1
Hall 1 Hall 2
Hall 3
Second generation RNB facility using the SPL as driver<100 A on « traditional » ISOL targets, >100 A on converterPost-acceleration to 100 MeV/u (cyclotron/LINAC)Storage/re-cycler ring
Ideas for exotic probes for RIB (RAMA@ECT*)
p-bar – antiprotonic atoms– Intersecting storage ring with 109 p-bar stored
• Electron cooling on both rings• Multi turn injection• Merging reactions
– muonic atoms– Cyclotron trap (PSI)– Hydrogen layer (RIKEN-RAL)– Storage ring
Conclusions
RIB are crucial in widening our understanding of the nuclear system when stretching the parameters
Low-energy RIBs with good beam quality is the optimal starting point for decay studies, laser physics, traps etc.
RIB overcome partly the fact that we now only have the stable and long-lived “ashes” of astrophysical processes
RIB and techniques used in the production and separation have important connections to other research fields
Large physics output obtained with “first-generation” RIB facilities – time to make a major step forward
Acknowledgements Collaborations:
IS304 (Mainz, Leuven, Montreal, CERN) IS320 (Aarhus, CERN, Darmstadt, Gothenburg, Madrid,
Orsay) IS367 (Gothenburg , Aarhus, Madrid, CERN, Darmstadt,
Örebro) IS374 (Caen, Gothenburg , Aarhus, Madrid, Troitsk, Orsay,
Mainz, CERN, Darmstadt) IS376 (Gothenburg , Aarhus, Madrid, Stockholm, CERN,
Darmstadt) IS402 (Orsay, GSI, MSU, Munich, CERN, Sao Paulo)