In-beam and isomer spectroscopy in the third island of inversion at EXOGAM+VAMOS

E.Clément Novembre 2011

In-beam and isomer spectroscopy in the third island of inversion at EXOGAM+VAMOSE.Clément (GANIL)

E.Clément Novembre 2011

Presence of core coupled states : Fe-like and Ni-likeD.Pauwels et al., PRC 79 (2009)A.Dijon et al, PRC 83 (2011)

Onset of deformation in Fe isotopesJ.Ljungvall et al., PRC 81 (2010)W.Rother et al., PRL 106 (2011)

Presence of single particle, collective and core-coupled states.I.Stefanescu et al., PRL 100 (2008)

68Ni

69Cu68Cu

67Co

67Ni

70Zn

70Cu

69Ni

66Co 68Co

66Fe

65Mn

65Fe 67Fe

65Co

64Fe

64Mn63Mn

Weakness of the N=40 shell gapM. Bernas et al., PLB 113 (1982)R.Broda et al., PRL 74 (1995)O.Sorlin et al.,PRL 88 (2002)C. Guénaut et al., PRC 75 (2007)

Core polarization O. Perru et al., PRL 96 (2006)

70Ni

E.Clément Novembre 2011

68Ni

69Cu68Cu

67Co

67Ni

70Zn

70Cu

69Ni

66Co 68Co

66Fe

65Mn

70Ni

65Fe

69Co

67Fe

69Cu : p(2p-1h) Single particle state by B(E2) measurement (I.Stefanescu et al., PRL 100 (2008) )

67Co : p(1p-2h)Shape isomer at N=40 : proton intruder state p (p1/2)+1 (D.Pauwels et al . PRC 78 (2008))

68Ni must present a p(2p-2h)intruder state withE(p(2p-2h) )=E(p(2p-1h) )+E(p(1p-2h))

p(2p-2h) intruder states at low energy π-ν residual energy.

0+ state (D.Pauwels et al . PRC 82 (2010))

E.Clément Novembre 2011

238U 6.33 A MeV

70Zn target Sed1

Sed2

11 EXOGAMGe detectors

No Dipole

45°Ionisation chamber (3 pads) + 4 Si detectors

2 Ge Eurogam phase 1

+2 Ge EXOGAM

detectors

VAMOS Spectrometer

MWPC

Q1Q2

coun

ts

∆Z/Z =1.1%

∆M/M=1.2%

Z identification

M identification

E.Clément Novembre 2011

168(1) keV

Prompt

69Cu67Ni69Ni

68Ni Isomer

PRELIMINARY

T1/2=216 +65/-50 nsIsomer

A. Dijon et al, to be submitted very soon …

E.Clément Novembre 2011

Gated on transitions in 67Ni

Gated on transitions in 69Cu

Gated on transitions in 69Ni

Gated on the 168 keV transition

Observed just for Z=28

E.Clément Novembre 2011

168(1) keV

Prompt

69Cu67Ni69Ni

68Ni IsomerT1/2=216 +65/-50 ns

A. Dijon et al, to be submitted very soon …

E.Clément Novembre 2011

168(1) keV

Prompt

69Cu67Ni69Ni

68Ni IsomerT1/2=216 +65/-50 ns

Compatible withsmall B(E2) value

PromptTransitions Half-life

E1 0.1 ps

E2 300 ns

M1 6 ps

M2 20 μs

E.Clément Novembre 2011

0+

0+1

0+3

2+1

4+1

2+2

5-25-

1

0+m2

68Ni

π(f7/2)-2

(1/2-m)

(7/2-)g.s

67Co

491

Shape isomerD.Pauwels et al.,

PRC 78 (2008)

0+g.s

66Fe

2+

B(E2

) =21

W.u

575

π(f7/2)-2

DeformedW.Rother et al., PRL 106 (2011)

Shape Coexistence scenario

Remarkable agreement with the predited position from the p(1p-2h) in 67Co and p(2p-1h) in 69Cu p(2p-2h) state Suggest the microscopical configuration

D. Pauwels et al, PRC 82, 027304 (2010)

* 70Zn(14C,16O)68Ni M. Girod et al PRC 37 (1988), at the Orsay Tandem

π(f7/2)-2 (p3/2)+1

E.Clément Novembre 2011

0+

0+1

2+1

0+m2

8+1

…

g9/2 d5/2p1/2f5/2p3/2f7/2

f7/2 p3/2 f5/2 p1/2

CalculatedGS0+

1

0+2

neutron

proton

Correlation energy : -30.9 MeVQ² = 4520 e²fm4 b ~ 0.4

LSSM – LPNS : F. Nowacki, K. Sieja for A. Dijon et al, to be submitted very soon …

Correlation energy : -7.6 MeVQ² = 899 e²fm4 b ~ 0.18

π(f7/2)-2

Occ

upat

ion

num

ber

Q² = 1579 e²fm4 b ~ 0.24

B(E2)cal= 0.9 W.u Exp : < 1.4 W.u (E0?)

E.Clément Novembre 2011

M. Martini, S. Péru for A. Dijon et al, to be submitted very soon …

68NiHFB-D1S

fully consistent QRPA calculations with D1S interaction

× Not p

rese

nt in th

e

ph-RPA ca

lculatio

ns× N

ot pre

sent i

n the

ph-RPA ca

lculatio

ns

p

p

n

E.Clément Novembre 2011

The solenoid mode in this experiment shows interesting results:Prompt and delayed gamma rays in coincidenceLifetime of isomer

A new isomer has been identified in 68Ni

Interpreted as a 2p-2h proton intruder superdeformed state across the Z=28 major shell closure

In agreement with SM calculations using the recent LPNS interaction In agreement with QRPA calculations

Similar microscopic configuration with 67mCo and 66Fe Shape coexistence in 68Ni

E.Clément Novembre 2011

Collaboration

E.Clément Novembre 2011

E.Clément Novembre 2011

S.M. Lenzi, F.Nowacki, A.Poves and K.Sieja, PRC 82 (2010)

K.Heyde and J.L. Woods, Rev.Mod.Phys (in press)

-3.8 MeV

F.Nowacki and K.Sieja for A. Dijon et al (2011)

Correlation energy : -30.9 MeVQ² = 4520 e²fm4 b ~ 0.4

Correlation energy : -7.6 MeV Q² = 899 e²fm4 b ~ 0.18

D.Pauwels et al., PRC 82 (2010)

E.Clément Novembre 2011

M. Bernas et al PLB B113,(1982)

Remember, at this time the 2+ at 2033 keV was not known : the 2.20(3) MeV state interpreted as a the 2+1

state

M. Girod et al PRC 37 (1988)

A 0+ state ? : Looking at the past …

E.Clément Novembre 2011

A 0+ state ? : Looking at the past …

M. G

irod et al PRC 37 (1988)