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