MINIBALL g -ray Spectroscopy far from Stability Overview Physics C ase MINIBALL @ REX-ISOLDE ‚Island of Inversion‘ Results Perspectives with HIE-ISOLDE

MINIBALL g-ray Spectroscopy far from Stability

• Overview Physics Case• MINIBALL @ REX-ISOLDE• ‚Island of Inversion‘ Results• Perspectives with HIE-ISOLDE

Peter ReiterIKP, University of Cologne

for the MINIBALL collaboration

Nuclear Structure and Dynamics Opatija, Croatia, July 9. – 13., 2012

Shell Model Physics with MINIBALL@REX-ISOLDE

transfer reactions at N=28 (Darmstadt, Munich)

46Ar

“Island of inversion” N=20Coulomb excitation &

transfer reactions (Darmstadt, Cologne,

Munich) 28,29,30Na29,30,31,32Mg Towards the doubly magic 78Ni

with Coulomb excitation and nucleontransfer reactions around 68Ni

(CERN, Leuven, Munich) 66,67,68Ni 67,68,69,70,71,73Cu 72,74,76,78,79,80Zn

Outline - Physics case - MINIBALL@REX-ISOLDE - Island of Inversion - Perspectives

Phys. Rev. C 84, 064323 (2011)Phys. Rev. C 82, 064309 (2010)Phys. Rev. C. 79, 014309 (2009)Phys. Rev. Lett. 100, 112502 (2008)Phys. Rev. C. 78, 047301 (2008)Phys. Rev. Lett. 99, 142501 (2007)Phys. Rev. Lett. 98, 122701 (2007)

Phys. Lett. B, 700 ( 2011) 181Phys. Rev. Lett. 105, 252501 (2010)Phys. Rev. Lett. 103, 012501 (2009)Phys. Rev. Lett. 94, 172501 (2005)

B(E2) measurements around 132Sn(Darmstadt, Munich)

122,124,128Cd138,140,142,144Xe 140,142,148Ba

g-factors in Te isotopes(Darmstadt, Madrid)

132,134,136Te

Shell Model Physics with MINIBALL@REX-ISOLDETowards the doubly magic 100Sn

(Lund, CERN) 106,107,108,109,110Sn

107,108In100,102,104Cd


Eur. Phys. J. A 44 (2010) 355Phys. Rev. C 80, 054302 (2009)Phys. Rev. Lett. 101, 012502 (2008)Phys. Rev. Lett. 98, 172501 (2007)

Shapes & collectivity with MINIBALL@REX-ISOLDE

Shapes and collectivity between Kr and Sr

(York, Cologne, Munich, Orsay,Grenoble, Saclay)

72Kr 88,92,94,96Kr 93,95,97,99Rb

96Sr

Shapes and collectivity

in the rare earth region

(Darmstadt, Saclay, Oslo)

138,140Nd140,142Sm 142Gd 144Dy

Collectivity near Z=50(York, Darmstadt)

116,118Te


Phys.Rev.Lett. 108, 062701 (2012)Phys.Rev.Lett. 98, 072501 (2007)

Octupole collectivityin heavy Rn, Ra isotopes

(Liverpool) 220,222Rn 222,224Ra

Shapes & collectivity with MINIBALL@REX-ISOLDE

Shapes in Hg, Pb, Po nuclei(Liverpool, Leuven, Jyväskylä) 182,184,186,188Hg 188,190,192,194,196,198Pb

198,200,202Po

Shapes and collectivityin light Po, Rn nuclei

(York, Jyväskylä)206Po

202,204Rn


The MINIBALLCoulomb excitation setup

segmented Si detector for particle detection (DSSSD)• 16 rings (front side)• 96 strips (back side)• angle coverage: θlab = 16-55°• ΔE-E measurement possible

(pad)


RIB production at ISOLDE

RIB Production:• 1,4 GeV protons• various targets• ionization• mass separation in

GPS/HRS• 800 RIBs available


Isomeric beams @ ISOLDE

6-

1+ (g.s.)

68Cu6- (g.s.)

1+

70Cu 3-

1+

6-

0

722

6-

1+

0

242

3-

101

• technique based on in-source laser spectroscopy (U. Köster et al., NIM B160, 528 (2000), L. Weissman et al., PRC 65, 024315 (2000))

• set the laser frequency to select and maximize the production

of the isomer of interest

g-Spectroscopy with Cu isomer beams: I. Stefanescu et al. PRL 98, 122701 (2007), E. Rapisarda et al. PRC 84, 064323 (2011)



Z=28 N=28

• realistic interaction (M. Hjorth-Jensen et al., Phys.Rep.26 (2004)

• model space: 1f5/2 2p3/2 2p1/2 1g9/2

outside 56Ni inert core;

SMI Calculations by N. Smirnova• hybrid interaction (S.Lenzi et al., PRC82, 05430(2010))

• model space:1f7/2 1f5/2 2p3/2 2p1/2 protons

1f5/22p3/22p1/21g9/22d5/2 neutrons 48Ca inert core

Coulomb excitation of isomeric states of 70Cu

SMII Calculations by K. Sieja

1g9/2

2p1/2

2p3/2

1f5/2

• NO proton-core excitations

• NO neutron-core excitations

Systematics of 6- 4- transition

Z=20 N=28

2p1/2

2p3/2

1f5/2

1f7/2

2d5/2

Neutrons excitations across N=50

Proton excitations across Z=28

1g9/2

RIB preparation @ REX-ISOLDE

Re-acceleration• acceleration of the ions in

the REX-LINAC• beam energy: 0,8-3,0 MeV/u

Acceleration up to Ra achieved


Charge breeding:• cooling and bunching of

the RIB in the REXTRAP• breeding to higher

charge states in the EBIS to A/q<4.5• breeding time up to 400

ms• A/q selection


224Ra (+120Sn) Coulomb excitation

P.A. Butler1, L.P. Gaffney1, M. Scheck1,2, F. Wenander3, for the IS475 collaboration1University of Liverpool, UK , 2Technical University Darmstadt, Germany, 3CERN-ISOLDE

- Heaviest REX-ISOLDE beam

- B(E3, 0+ ↦ 3-)

E.K. Warburton, J. A. Becker and B. A. Brown, PRC 41 (1990) 1147.

20

s1/2

f7/2

d5/2

d3/2

p3/2f7/2

d3/2

p3/2

d5/2

s1/2

0p0h, spherical 2p2h (intruder), deformed


0+

2+

30Mg

E2

32Mg… 38Mg

E2

2+

0+

T. Motobayashi, et al.; PLB 346 (1995) P Doornenbal et al

30,31,32Mg, 30Na

0+

0+

2+

30Mg 32Mg

???

31Mg

E0 E2E2

inversion normalsd

configurations

intruderfp

configurations

2+

0+

0+

Where are the borders?

How does transition into island of inversion occur ?

Does picture of shape coexistence hold?

d3/2

+f7/2

-


H. Scheit et al; in prep.M. Seidlitz et al; Phys. Lett. B 700 (2011) 181

O. Niedermeier et al. Phys. Rev. Lett. 94, 172501 (2005)

Neutron number

Coulomb excitation of 30,32Mg

‚Safe‘ energy Coulomb excitation at 2.25 MeV/u

MINIBALL measures with small uncertaintyB(E2) values from first excited 2+ statesto ground state in 30,32Mg


G. Neyens et al., PRL 94, 022501 (2005)D. Yordanov et al., PRL 99, 212501 (2007)

laser spectroscopy and -NMRg-factor and spin for 31Mg and 33Mgfrom sign of g-factor parity

31Mg, Ip = 1/2+ (sd)-3 (fp)2

33Mg, Ip = 3/2- (sd)-2(fp)3

pure 2p-2h intruder ground states !

Al28

Al29

Al30

Al31

Al32

Al33

Al34

Al35

Al36

Mg27

Mg28

Mg29

Mg30

Mg31

Mg32

Mg33

Mg34

Mg35

20

d3/2

+f7/2

-

20

31Mg (N=19)

d3/2

20

33Mg (N=21)f7/2

Normal ground state configurations:

Ip=3/2+ Ip=7/2-

pf

sd

Intruder ground state configurations:

20

31Mg (N=19)

d3/2

Ip=1/2+

20

33Mg (N=21)

Ip=3/2-

g-factor and spin of the 31,33Mg ground state


Renewed -decay studies31Mg F. Maréchal et al., PRC 72, 044314 (2005)33Mg V. Tripathi et al., PRL 101, 142504 (2008)

Coulomb excitation 31Mg


31Mg Results


M. Seidlitz et al; PLB 700 (2011) 181 G. Neyens, Phys. Rev. C 84, 064310 (2011)M. Kimura, Phys. Rev. C 75, 041302(R) (2007)


Coulomb excitation of 30Na, higher lying states?

B(E2, 2+ → (4+)) = 108 (33) e2fm4 (preliminary!)

theoretical predictions: B(E2, 2+ → 4+) = 90 e2fm4

background subtracted, Doppler corrected for 30Na30Na ((3+) → 2+)

30Na ((4+) → (3+))30Na ((4+) → 2+)

beam time: 80 hoursbeam intensity: 550 ions/sec

more beam time Oct. 2012

0+

0+

2+

30Mg 32Mg

???

31Mg

E0 E2E2

inversion normalsd

configurations

intruderfp

configurations

2+

0+

0+

Does picture of shape coexistence hold?

d3/2

+f7/2

-


Shape coexistence in 30Mg

30Mg 32Mg 0+

1

0+2 0+

2

0+1

W. Schwerdtfeger, et al; PRL 103, 012501 (2009)


- electron spectroscopy after -decay at ISOLDE- first excited 0+ state at 1789 keV in 30Mg

The MINIBALL T-REX setup

RIB

• large solid angle (58% of 4π)• position sensitive• PID (ΔE-E): p, d, t, α, … and e- from β-decay (!)

V. Bildstein, K. Wimmer,Th. Kröll, R. Gernhäuser et al. (funded by TU München,KU Leuven, U Edinburgh, CSNSM Orsay, TU Darmstadt)

T-REX: Si detector array for Transfer experiments at REX-ISOLDE

Technical details:Barrel: 140 mm ΔE / 16 resistive strips 1000 mm E / padBackward CD: 500 mm ΔE / DSSSD 500 mm E / pad


t(30Mg, 32Mg)p – two-neutron transfer

• 3H loaded Ti foil (40 mg/cm2 3H, 10 GBq)• 30Mg @ 2 MeV/u• 4·104 part/s / 150 h beam on target• Q00 = -295(20) keV• Two states populated: ground state and new state at 1083(33) keV


K. Wimmer et al; PRL 105, 252501 (2010)


normalsd

configurations

intruderfp

configurations

K. Heyde, J.L. Wood, REV. OF MOD. PHYS., Vol 83, (2011) 1467S. Grévy et al,; ARIS2011 proceedings

0+ 2719

0+

0+2+

30Mg 32Mg

E0 E2E2

2+

0+

0+


d(66Ni,67Ni)p – the 68Ni region (N=40)

preliminaryJ. Diriken, P. van Duppen, R. Raabe, et al.; IKS-KU Leuven for the IS469 collaboration



J. Diriken, P. van Duppen, R. Raabe, et al.; IKS-KU Leuven for the IS469 collaboration

preliminary

• proton gated g-spectrum• g-transitions up to 5800 keV• p-g-g- coincidence analysis



Ex=3600(250) keV

Eg=3619(30) keV

Ex [

keV

]

Eg [keV]

shell closure at N=40?

NNDC

High resolution of MINIBALL allows to resolve states and to analyse angular distribution

preliminary

J. Diriken, P. van Duppen, R. Raabe, et al.; IKS-KU Leuven for the IS469 collaboration

HIE-ISOLDE


• intensity upgrade• energy upgrade

2014

2016

1.2 MeV/u

3 MeV/u

5.5 MeV/u

10 MeV/u

8 MeV/u


Transfer reactions at HIE-ISOLDEHigher energies at HIE-ISOLDE will be favorable for transfer reaction studies with heavy beams!

Show case example: d(132Sn,133Sn)p

FRESCO calc‘s by K. Wimmer (NSCL, MSU)

Several HIE-ISOLDE LoIs based onMINIBALL & T-REX:- shell evolution- shape coexistence- pairing correlations ó pair transfer- nuclear astrophysics: (d,p) ó (n,g) capture reactions

Upgrade of T-REX -> flexiblegeometry of Si detectors

Fusion veto detector

Spectrometer to identify heavy transfer products

Summary• MINIBALL spectrometer very well suited for REX-ISOLDE• Physics case covers the range from 17F to 224Ra• First years: Shell model physics and Coulomb excitation• Recent developments: - isomeric and heavy beams - T-REX transfer reactions & g-ray spectroscopy • Major perspective: HIE-ISOLDE


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HIE-ISOLDEOutline - Physics case - MINIBALL@REX-ISOLDE - Island of Inversion - Perspectives

● MINIBALL + T-REX● New instrumentation:

MAYA/ACTAR active target SPEDE - SPectrometer for Electron DEtection in radioactive beamHELIOS superconducting magnet for charged particle detectionPARIS (Photon Array for studies with Radioactive Ion and Stable beams) GASPARD (GAmma Spectroscopy and PArticle Detection)Neutron detectorsTSR storage ring

● Magnetic spectrometer or separator for channel selection

Mark Huyse, IKS K.U. Leuven ISOLDE workshop 2010


C. Thibault, et al.; PRC 12 (1975) 644

‚Island of Inversion‘First and recent results from ISOLDE

masses show considerable deviations for nuclei around Z=11, N=20. additional binding energy

Charge radii differences from isotope shift measurement D.T. Yordanov, et al.; PRL 108 (2012) 042504

RIB preparation @ REX-ISOLDE

Charge breeding:• cooling and bunching of

the RIB in the REXTRAP• breeding to higher

charge states in the EBIS to A/q<4.5• breeding time up to 400

ms• A/q selectionPossibility of in-trap decay during charge breeding:

61Mn → 61Fe

J. Van de Walle et al., CERN-INTC-2009-006 (2009)



6-fold segmented, encapsulated MINIBALL detector

Collaboration: Köln, Heidelberg, München, Leuven


Triple cluster detector3 x core + 3 x 6 segmentsIKP Köln and CTT

PreamplifierIKP KölnMPI-K Hd

Digital high resolution spectroscopy electronics

40 MHz digitizer: DGF 4C Company XIA


Pulse shape analysis and position sensitivity

in-beam data:(line width after Doppler correction) Abs. Eff. 8 %, ΔΘ = 3.30

Deviations from classical shell model


Transfer to ground state in 32Mgg.s. occupation numbers using effective USD / SDPF-M interactions:B. H. Wildenthal, Prog. Part. Nucl. Phys. 1, 5 (1984) T. Otsuka et al., Prog. Part. Nucl. Phys. 47, 319 (2001)

Transfer to ground state in 32Mg• pure transfer to (f7/2)2 to small • large contribution from (p3/2)2 needed (a > 0.7) SDPF-M underestimates the p3/2 content in the wave functions

Transfer to excited 0+ state in 32Mg• wave function similar to g.s. in 30Mg• two-neutron spectroscopic amplitudes for pure sd → sd transitions • cross section underestimated, small (p3/2)2 amplitude (a ≈ 0.3)

a

Transfer to excited 0+ state in 32Mg


K. Wimmer et al; PRL 105, 252501 (2010)




electric monopole (E0) transition to ground state: r2(E0)= (26.2 (7.5)) x 10-3

beyond-mean-field calculations with Gogny force:• two competing configurations, small mixing • largely different intrinsic quadrupole deformation • ground state: 1d3/2 neutrons• first excited 0+ state: 1f7/2 neutrons

predictions for 32Mg

Beam quality, monitoring, quantitative composition

Laser ON

Laser OFF

Measured with ionization chamber (ΔE-Erest)at the MINIBALL beam dump position


Short term perspectivesOutline - Physics case - MINIBALL@REX-ISOLDE - Island of Inversion - Perspectives

• 2011 campaign- Coulex experiments: 188;..,198Pb, 140Nd, 96Kr, 220Rn, 208Rn, 128Cd, 72Kr, 30Na, 98Sr- transfer experiments- g-factor measurements

Discussion of physics campaign during CERN shut down periodMINIBALL workshopUniversity of Cologne 27.-28. February or March 5.-6. March 2012.

• 2012 campaign

• 2013 CERN shut down


t(44Ar,46Ar)p – probing N=28

Analysis by K. Nowak, TU München)Spokesperson: K. Wimmer

Identified protons g-rays in coincidence with protons

Transfer to gs of 46Ar

Weakening of N=28 closure below 48Ca?è onset of deformation / shape coexistence? Search for the second 0+ state

O. Niedermeier, et al., Phys. Rev. Lett. 94, 172501 (2005)

Neutron number

Coulomb excitation of 30,32Mg

‚Safe‘ energy Coulomb excitation at 2.25 MeV/u

MINIBALL measures with small uncertaintyB(E2) values from first excited 2+ statesto ground state in 30,32Mg


E.K. Warburton, J. A. Becker and B. A. Brown, PRC 41 (1990) 1147.

20

s1/2

f7/2

d5/2

d3/2

p3/2f7/2

d3/2

p3/2

d5/2

s1/2

0p0h, spherical 2p2h (intruder)


0+

2+

30Mg

E2

32Mg

E2

2+

0+

T. Motobayashi, et al.; PLB 346 (1995) 9

30,31,32Mg, 30Na

886

792 722

660 660

collective properties of 31Mg

F. Maréchal et al., Phys. Rev. C 72, 044314 (2005)M. Kimura, Phys. Rev. C 75, 041302(R) (2007)

- -decay studies of 31Mg at GANIL

- shell model calculation sd-fp valence space ANTOINE code, effective interaction SDPF-NR

collective properties of positive K=1/2 rotational band of 31Mg:excitation energy, quadrupole moment Q, B(E2), magnetic moment μ, B(M1)


GOSIA Coulex calculationResults:- one step E2 excitation

- decay of (5/2+,3/2+) level via M1 transition

- results confirms strong collective

excitation - rotational sequence: 1/2+ → 3/2+ → 5/2+

B(M1, 5/2+→ 3/2+)=0.1 – 0.5 µn

2

B(E2, 1/2+→5/2+) = 182 e2fm4


M. Seidlitz et al; PLB 700 (2011) 181M. Kimura, Phys. Rev. C 75, 041302(R) (2007)


Collective properties of the Na-Isotopes

B(E2, 2+ → (3+)) = 147 (21) e2fm4

(Ettenauer et al., Phys. Rev. C 78, 017302, 2008)

Y. Ut

suno

, et

al.,

Phys

. Rev

. C70

, 044

307,

200

4

B(E2, 3/2+ → (5/2+)) = 140 (25) e2fm4

(Hurst et al., Phys. Lett. B 674, 168-171, 2009)theoretical predictions:B(E2, 3/2+ → 5/2+) = 111-135 e2fm4

B(E2, 3/2+ → 7/2+) = 57 e2fm4

theoretical predictions:B(E2, 2+ → 3+) = 168 e2fm4

B(E2, 2+ → 4+) = 90 e2fm4

The „Island of Inversion“

(5/2+)

? (3+) ?


Coulomb excitation of 30Na, higher lying states?

B(E2, 2+ → (4+)) = 108 (33) e2fm4 (preliminary!)

theoretical predictions: B(E2, 2+ → 4+) = 90 e2fm4

background subtracted, Doppler corrected for 30Na30Na ((3+) → 2+)

30Na ((4+) → (3+))30Na ((4+) → 2+)

measuring time: 80 hoursbeam intensity: 550 ions/sec

Follow up beam time Oct. 2012

GOSIA Coulex calculationResults:- one step E2 excitation

- decay of (5/2+,3/2+) level via M1 transition

- results confirms strong collective

excitation - rotational sequence: 1/2+ → 3/2+ → 5/2+

B(M1, 5/2+→ 3/2+)=0.1 – 0.5 µn

2

B(E2, 1/2+→5/2+) = 182 e2fm4


M. Seidlitz et al; PLB 700 (2011) 181M. Kimura, Phys. Rev. C 75, 041302(R) (2007)




electric monopole (E0) transition to ground state: r2(E0)= (26.2 (7.5)) x 10-3

beyond-mean-field calculations with Gogny force:• two competing configurations, small mixing • largely different intrinsic quadrupole deformation • ground state: 1d3/2 neutrons• first excited 0+ state: 1f7/2 neutrons

predictions for 32Mg

Short term perspectivesOutline - Physics case - MINIBALL@REX-ISOLDE - Island of Inversion - Perspectives

• 2011 campaign- Coulex experiments: 188;..,198Pb, 140Nd, 96Kr, 220Rn, 208Rn, 128Cd, 72Kr, 30Na, 98Sr- transfer experiments- g-factor measurements

Discussion of physics campaign during CERN shut down periodMINIBALL workshopUniversity of Cologne 27.-28. February or March 5.-6. March 2012.

• 2012 campaign

• 2013 CERN shut down

Documents

MINIBALL g -ray Spectroscopy far from Stability Overview Physics C ase MINIBALL @ REX-ISOLDE ‚Island of Inversion‘ Results Perspectives with HIE-ISOLDE