Riccardo Raabe – Instituut voor Kern- en Stralingsfysica, K.U.Leuven Huelva 09/11/2011...

Riccardo Raabe – Instituut voor Kern- en Stralingsfysica, K.U.Leuven Huelva 09/11/2011

Introduction REX-ISOLDE Results The future

Transfer reactions at ISOLDE:recent results and future plans

Riccardo Raabe (IKS, K.U.Leuven)

SeminarGrupo de Estructura de la Materia,

Universidad de Huelva09 Nov 2011



Overview

IntroductionThe structure of nucleifar from stabilityTransfer reactionsas spectroscopic toolAvailable beams

REX-ISOLDEExperimental setupAdvantages and problems

Some results11Be(d,p)30Mg(d,p)30Mg(t,p)66Ni(d,p)78Ni(d,p)

The futureHIE-ISOLDEInstrumentation:magnets, active targets,a ring



The structure of nuclei far from stability

What happensfar from stability?

Evidence for stableconfigurations:

Abundances

Binding energy

Energy of the first excited state



The NN interaction

One-body SO potential:

O. Sorlin, M.-G. Porquet, PPNP 61 (2008) 602

Tensor interactiononly if S=1 (parallel spins)

T. Otsuka et al., PRL 95 (2005) 232502



Transfer reactions as spectroscopic tool

Q-values position of levels

Angular distribution spin and parities

Cross sections (relative) spectroscopicfactors, ANCs

Measuring with RIBsInverse kinematicsLow intensity beams(“thick” targets)Detection ofbeam-like particle spectrometertarget-like recoil Si array-rays Ge array

ProblemsEnergy (angular) resolutionEfficiencyBackground



REX: Radioactive beam EXperiment @ ISOLDE



LINAC

REXTRAP: Penning trapat 60 keV

REXEBIS: charge breeding τ=10-100 ms, A/q <4.5efficiency up to 30%

Separator: q/A resolution ≈150

LINAC: L = 10 m0.8 < Ebeam< 3.0 MeV/nucleon



T-REX and Miniball

Miniball24 HPGe6-fold segmentedε ≈ 7% @ 1.3 MeV

T-REX V. Bildstein, K. Wimmer

Resolution ≈5 degΔE-E for PIDε ≈ 60%



Available ions

Currently availableTestedFeasible

RILIS Laser Ion Source

+ isomeric beams(also post-accelerated)



Transfer reactions at REX-ISOLDE

28Na(d,p)11Be(d,p)

30Mg(t,p) 30Mg(d,p)

66Ni(d,p) 78Zn(d,p)

44Ar(t,p)

66Ni(t,p)

72Zn(t,p)



Issues at 3 MeV/nucleon

ModelsWhat are we measuring?

Absolute SF have little (or no) meaning Relative SF; ANCs

Coupling of channels DWBA?Angular distributionsnot characterized

Calculation: T. Roger

66Ni(t,d)



Issues at 3 MeV/nucleon

ModelsWhat are we measuring?

Absolute SF have little (or no) meaning Relative SF; ANCs

Coupling of channels DWBA?Angular distributionsnot characterized

Experimentally(Very) low-energy protons poor resolution use thick target and coincident -ray detectionProtons from fusion-evaporation (on C, Ti)No channel identification energy has to be limited



Coincident -ray detection

…with MiniballExcellent resolution(necessary as density of states becomes important)

butNo gs-to-gs transferThick target poor resolution for E protonIsomers! slow coincidence setup



Transfer reactions at REX-ISOLDE

28Na(d,p)11Be(d,p)

30Mg(t,p) 30Mg(d,p)

66Ni(d,p) 78Zn(d,p)

44Ar(t,p)

66Ni(t,p)

72Zn(t,p)

Kathrin Wimmer

Jan Diriken

Jytte Elseviers

Katharina Nowak

Vinzenz Bildstein

Riccardo Orlandi

Thorsten KroellJacob Johansen


Introduction REX-ISOLDE Results The future11Be+d

J. Johansen, K. RiisagerMotivation: halo nucleus, N = 8, clusters…Goals: separation of states in 12Be,check spectroscopic factors of 0+

1d3/22s1/2

ν

8

1s1/2

1p1/2

1p3/2



1d3/22s1/2

ν

8

1s1/2

1p1/2

1p3/2

11Be+d

J. Johansen, K. RiisagerMotivation: halo nucleus, N = 8, clusters…Goals: separation of states in 12Be,check spectroscopic factors of 0+

gammas



J. Johansen, K. Riisager

320 keV

11Be(d,d’)




0+

2+

2+ to 0+

2− to 2+

2+ to 2+

11Be(d,t)




2.1 MeV - ≈ 7000 cts

2.7 MeV - ≈ 3000 cts

11Be(d,p)

S(0+1) = 0.29

0+2 2.24 MeV

T1/2 = 300 ns

1‒



Mapping the island of inversion

As protons are removed from the πd5/2 orbital, the νd3/2 becomes more unbound N = 20 gap reduction,new gap at N = 16intruder states appearingcollectivity, deformation

s1/2

d5/2

d3/2

f7/2

s1/2

πν

14

20

p3/2

Y. Utsuno et al.,PRC 60 (1999) 054315

2016

14

12

20


Introduction REX-ISOLDE Results The future30Mg(d,p)

V. BildsteinIsland of inversion at Z = 12

Single particle structureof excited states in 31Mg

Elastic

31Mg

G. Neyens et al., PRL 94, 022501 (2005)F. Maréchal et al., PRC 72, 044314 (2005)



V. Bildstein

170 keV

Δℓ = 1 negative parityCross section to gs and firstexcited state from total proton yieldComparison cross section to theory(Nilsson model) info on deformation


Introduction REX-ISOLDE Results The future30Mg(t,p)

K. Wimmer et al., PRL 105 (2010) 252501Looking for the spherical 0+ in 32Mg

30Mg(t,p)32Mgwave functions have large overlap 12

20

Y. Utsuno et al.,PRC 60 (1999) 054315

2016




30Mg(t,p)32Mgwave functions have large overlapTritium-implanted Ti foil3H 40 μg/cm2

Activity 10 GBq30Mg at 1.8 MeV/nucleon4.6x104 pps




Ground and excited state populated




Ground and excited state populated both ΔL = 0




-rays in coincidence:0+

2 at 1058 keV

0+2 lower in energy and more long-living

than expectedLarger cross section than predicted

Some (2p3/2)2 necessary


Introduction REX-ISOLDE Results The future66Ni(d,p)

J. DirikenThe strange magicity of 68Ni

Increased E* of the first 2+ state

Local minimum of the B(E2)

however

No irregularities in the S2n

Check single-particle statesin neighbouring nuclei

2d5/2

1g9/2

ν

2p1/2

2p3/2

401f5/2

28

50

1g7/2



J. DirikenProton-gamma coincidences



J. DirikenProton-gamma coincidences

Candidate for the νd5/2 state(across N=50)


Introduction REX-ISOLDE Results The future78Zn(d,p)

R. OrlandiQuenching of N = 50

What is the valueof the N=50 gap in 78Ni?

O. Sorlin, M.-G. PorquetProg. Part. Nucl. Phys. 61 (2008) 602

Van de Walle et al.Phys. Rev. Lett. 99 (2007) 142501

80Zn


Introduction REX-ISOLDE Results The future78Zn(d,p)

R. Orlandi

Coincident rays (preliminary)

Calculations:K. Sieja (Strasbourg)

79Zn



High Intensity:LINAC4 + new target stationsBeam quality improvementHigh Energy:up to 10 MeV/nucleonsuperconducting linac

The future: HIE-ISOLDE

project manager: Y.Kadi (CERN)

mid 2014

end 2015

end 2016



HIE-ISOLDE Letters of Intent

13 LOIs on transfer @ 10 MeV/u

Pb region accessible


Introduction REX-ISOLDE Results The futureHIE-ISOLDE: Beam lines and Instrumentation

slides: E. Siesling



Miniball

Miniball

Actar-TPC / Helios

TSRSpectrometer

Exp. station

HELIOSHELIOSACTAR-TPCACTAR-TPC

HIE-ISOLDE: Beam lines and Instrumentation

slides: E. Siesling



HIE-ISOLDE: “Test” Storage Ring

TSR at the Max-Planck Institute Heidelberg

TSR@Hie-ISOLDE LoI Jan 2011 TDR in progressK. Blaum, Y. Litvinovand ≈100 collaborators

Unique: storage ring at an ISOL facility

Physics cases: atomic physics,reactions for nuclear structure and astrophysics, decays…



Summary and perspectives

3 MeV/nucleon: challenges on theory and experiment

-ray detection: very powerful to determine energies

Unique beams,combination of various reaction and decay techniques

The future

Increase in energy and intensity: HIE-ISOLDEInstrumentation:

Upgrade T-REX, ACTAR-TPC, HeliosSpectrometerStorage ring



Time structure



T-REX


Introduction REX-ISOLDE Results The futureIssues at 3 MeV/nucleon

calculations by N. Patronis28 DWBA calculations 64Ni(d,p)65Nig

1.00 fm < r < 1.40 fm0.50 fm < a < 0.75 fm

14 DWBA calculations 64Ni(d,p)65Ni1.00 fm < r < 1.40 fm0.50 fm < a < 0.75 fm

Data:T.R. Anfinsen et alNPA 157 (1970) 561



V. Bildstein

g.s.: 1/2+[200], prolateMixed, mainly 2s1/2DL=0 P

50 keV: 3/2+[202], prolate1d3/2 orbitalDL=2 P

221 keV:3/2-[321], prolate1f7/2 orbitalDL=3 ~

I. Hamamoto, PRC 76, 054319 (2007)

2p3/2[312 3/2]

221 keV:3/2-[321], oblateMixed, mainly 2p3/2DL=1 P

Riccardo Raabe – Instituut voor Kern- en Stralingsfysica, K.U.Leuven Huelva 09/11/2011...

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Transcript of Riccardo Raabe – Instituut voor Kern- en Stralingsfysica, K.U.Leuven Huelva 09/11/2011...