L.M. Fraile
Grupo de Física Nuclear Experimental
Grupo de Física Nuclear ExperimentalGrupo de Física Nuclear Experimental
GF
E
N
CSICIEM
Nuclear Structure of Exotic NucleiM.J. García Borge: Investigadora CientíficaO. Tengblad: Científico TitularA. Jungclaus: Heisenberg Fellow (UAM 1/2)M. Turrión: Postdoc TARGISOL projectL.M. Fraile: Complutense, Doctor asociadoY. Prezado: PostdocR. Boutami: PhD studentD. Escrig: PhD studentM. Madurga: PhD studentA. Sabán: PhD student
L.M. Fraile
Research outlineLight nuclei
• Low Energy beams: Beta decay studies, spectroscopy
ISOLDE and JYFL: β- delayed multi-particle breakup (Aarhus-Göteborg-Jyväskylä-Madrid)
• Energies around Coulomb barrier: Characterization of halo nuclei
REX-ISOLDE: study of halo systems, unbound 7He & 10Li study the transition from weakly bound systems to the continuum (Aarhus-Darmstadt-Göteborg-Madrid-Moscow)
Louvaine La Neuve Signatures of dipole polarizability in the halo nuclei 6He & 11Li.(Huelva-Madrid-Sevilla…)
• Relativistic beams: halo nuclei identification and properties
GSI (FRS, LAND)GANIL
L.M. Fraile
Research outline II• Direct reaction studies of astrophysical interest
CMAM (UAM Madrid), Tandetron 5MV
Medium-heavy masses: spectroscopic studies• N=Z nuclei
ISOLDE• High spin studies
Legnaro: In beam investigations of nuclei around doubly-magic 100Sn using stable and radioactive ion beams (Dresden-Köln-Legnaro-Madrid-Valencia)
• Octupole correlations / Fast timing techniqueISOLDEGANIL/LISE
L.M. Fraile
β-delayed particle emission - ISOLDE9C → 9B* → p + α + α CERN-IS3619Li → 9Be* → n + α + α (In preparation)12N → 12C* → α + α + α Jyväskylä12B → 12C* → α + α + α CERN-IS40411Li IS417
Reaction studies - CMAM tandem3He + 6Li → 9B* → α + α + pd + 7Li → 9Be* → α + α + np + 11B → 12C* → α + α + α
3He + 9Be → 12C* → α + α + α
⇐ Selection rules ⇒⇐ Energy window ⇒
⇐ Feeding mechanism ⇒⇐ Isospin ⇒
Feed states of definite spin & parity Defined by the Q-valueClean, the operator is knownF & GT transitions feed states of
well defined spin
Feeds many different statesLimited by the accelerator energyNot trivial, resonance or direct reactionsDepends on beam and target chosen
Multiparticle decays
5 DSSSD telescopes ultra thin window, design IEM64 +8 electronic channelsEquipment for setting up beam line at CMAM-tandem
L.M. Fraile
Result 12C* (12.71 MeV) Jyväskylä
Break-up mechanism ?Sequential or simultaneous
Data
Sequential
Simultaneous
Phys. Rev. Lett. 91 (2003) 082502
L.M. Fraile
DSSSD new design
Highly segmented: 50x50 cm2
16x16 strips of 3x50 mm2
256 detector pixels of 3x3 mm2
in only 32 read out channels
Negative bias
2.2 pF
Al
2.2 pF
Al
n-Si p+n+
dead layer200 nm Al400 nm doping
100 nm deadlayer
60 µm no β response
New design100 nm dopingGrid contact
2.2 pF22 MΩ
Outp+
TST+
SiO2
TST-
Outn+22 MΩ
2.2 pF
NIM, submitted
L.M. Fraile
REX-ISOLDE – IEM
Li103
Be104
21
0
21
23
0
693
21
0
T
T T
T
−⇒
==
+
+⇒
pLi
T=2
T=1
IS371
9Li
d-polyethylen
IS367 Transfer reaction at lowenergy ⇒ s-wave pickup (d-target) p-wave pickup (Be-target) Characterize the gs and1st exited state of the unbound nucleus 10Li
Elastic resonancescattering to investigate E, Jπ of lowest T=2 states in 10Be analogues of gs and 1st
excited state of 10Li
Post-accelerated 2.3 MeV/u 9Li beam fromREX-ISOLDE on d-polyethylen, Be, methane gas target respectively.
Resonance protons detected with 2x 64 µm DSSSD-Si telescope placed at 5cm, covering25-800 each in vacuum (IS367) or a set of detectors in methane gas (IS371).
L.M. Fraile
Study of unbound nuclei at REX-ISOLDE (IS367, PRELIMINARY)
9Li 2MeV/u
d
Protons from 10Li
L.M. Fraile
GSI 11LiReaction mechanisms• Coulomb dissociation• Diffraction dissociation• Absorption dissociation• Final state interaction
Nuclear Models• Shell Model• Intruder states• 3 body model• core + halo articles• clusters
ExperimentVariables
Beam energy 30 1500 MeV/ATarget material C PbProjectile 6He 19C
Observablesn - momentum distributioncharge fragment momentuminvariant mass spectraangular correlations
The true momentum distribution of the halo n construct the wave functions (s and p components) spatial distribution
L.M. Fraile
Dipole polarizability of halo nucleiIEM – Sevilla – Huelva
LEDA-Louvain Edingburgh Detector ArrayDINEX-telescope
... Optical model
- - - large diffusenessparameter
Dipole polarizability included
Elastic cross section of 6He on 208Pb divided by theRutherford cross section at 19 MeV lab energy.
6He Lovain-la-Neuve - PH189 11Li REX-ISOLDE - IS399One important aspect which differentiates weakly bound nuclei from normal is the Coulomb dipole polarizability. The strong Coulomb field of the targetdistort the 6He (11Li) projectile, so that the 4He (9Li) core is pushed away fromthe target while the halo neutrons remain unaffected by the Coulomb field.
L.M. Fraile
In-beam γ-ray spectroscopy using 4π Ge arrays
Magnetic rotation and shapetransition in the A=70-90 region
first magnetic rotation in A≈80 in 82,84Rb
triaxiality and band termination in 72,73,74Br
superdeformation in 91Tc
high-spin structure in spherical 89,90Sr and 90Y
Study of neutron-rich nucleiusing incomlete fusion reactions
band crossing region in heavy Dy160,162Dyvibr. vs. intr. excitations in 112,114Cd
high-K states and triaxiality in Os
Shell structure around 100Sn:lifetime and magnetic moment measurements
β-decay of and Coulomb exc. of 100,102Sn
L.M. Fraile
TARGISOL Database/Web Application
http://www.http://www.targisoltargisol..csiccsic..eses
Effusioneffusion in the enclosure until the ion source
Diffusiondiffusion from the place of creation to the surface of the target
diffusion on the container
Proton beam(1.4 GeV)
Radioactive ion beam
Magnet
Container
Ion Source
But also:-rediffusion process-desorption time-wall collisions-sticking process-diffusion and effusion arenot subsequent steps