in-beam gamma-ray spectroscopy at ribf

RCNP

In-beam gamma-ray spectroscopy at RIBF

AOI NoriRCNP Osaka Univ.

May 31, 2012NN2012

0. Introduction

1.Deep inside (or beyond) island-of-Inversion-- South of Island-of-Inversion-- East of Island-of-Inversion

2.Neutron rich Si isotopes N~28

3.Next 　 step

RCNP

neutron skin

32Mg: large deformation

solar neutrino production

heavy hydrogens

explosive hydrogen burning

Nuclear Strucuter shell closure p & n decoupling

Astrophysics solar fusion explosive burning

16C: “egg” structure ? decoupled n-motion

28O: particle unstable

new magic #, N=16

neutron halo

molecular structure

neutron skin

Magic # (N=20) disappears.


Exotic structure in exotic nuclei

RCNP

neutron skin

32Mg: large deformation

solar neutrino production

heavy hydrogens

Exotic structure in exotic nuclei

explosive hydrogen burning

Nuclear Strucuter shell closure p & n decoupling

Astrophysics solar fusion explosive burning

16C: “egg” structure ? decoupled n-motion

28O: particle unstable

new magic #, N=16

neutron halo

molecular structure

neutron skin



RIBF More exotic Heavier nuclei

In beam-γ, First few years East and South of Island-of-inversion N~28

Intense 48Ca beam (~200pnA)

RCNP

• 2008 DayOne 　 with 48Ca32Ne, 31,33Na

H. Scheit, P. DoornenbalPhys.Rev.Lett., 103:032501, 2009./Phys.Rev. C, 81:041305, 2010.

• 2010 48Ca campaign~42Si S. Takeuchi, M. MatsushitaA>36Mg P. Doornenbal, H. Scheit~Al, P David Steppenbeck

33Mg D. Bazin

• 2011 U campaign (~3 pnA)~132Sn H. Wang, NA

• 2012 Xe campaign~10xSn P. Doornenbal et al.

A. Obatelli et al.,

In-beam g-ray spectroscopy at RIBF

RCNPIsland-of-Inversion

31Na 　 (Z=11, N=20)C. Thibault et al. PRC12(75)644

E.K. Warburton et al., PRC41(90)1147.

First proposed from massesMass


31Na 　 (Z=11, N=20)C. Thibault et al. PRC12(75)644

E.K. Warburton et al., PRC41(90)1147.

First proposed from massesMassEx(2+)moments…

RCNPStudy of Island-of-Inversion via 2+, 4+ states in E-E nuclei

Evolution of collectivity

B(E2;0+2+) : Measure of Collectivity

Ex(2+) : Alternative ∝ 　 B(E2) 　　 (at least locally)

R4/2 = Ex(4+) / Ex(2+) : Type of Collectivity

( Ex in odd-A nuclei )

~


T. Motobayashi et al., Phys. Lett. B346, 9(95)

Deformed (B(E2))

Deformed (Ex(2+))

RCNPIsland-of-Inversion before RIBF

Deformed (B(E2))

Deformed (Ex(2+))

RCNPFurther into and beyond Island-of-Inversion

Deformed (B(E2))

Deformed (Ex(2+))

　?

RCNPBigRIPS/ZeroDegree @ RIBF

BigRIPS/ZeroDegree

RCNP

γ-ray spectroscopy setup @ BigRIPS/ZeroDegree

F7

F7

F5

F1

IRC

F2 F8

F11

F3

F12

ProductionTarget

SRC

1st stage　 separation 2nd stage

analysis ZeroDegreeanalysis of 2ndaryreaction products

Around the island of inversion (32Ne …), 42SiBut unable to continue due to activation problem.

Scheit et al.Takeuchi et al.

RCNP

F7

gTargetF7

F5

F1

IRC

F2 F8

F11

F3

F12

ProductionTarget

SRC

1st stage　 separation 2nd stage

analysis ZeroDegreeanalysis of 2ndaryreaction products

Around the island of inversion (32Ne …), 42SiBut unable to continue due to activation problem.

Scheit et al.Takeuchi et al.

γ-ray spectroscopy setup @ BigRIPS/ZeroDegree

Jan. 11, 2011

32Mg(p,p’) b~0.3

H.Hasegawa, Master’s thesis, Rikkyo Univ., 2003

Ener

gy (k

eV)

Emission angle of g rays 20°160°

RCNPFurther into Island-of-Inversion ?

Deformed (B(E2))

Deformed (Ex(2+))

　?

RCNPSouth of Island-of-Inversion ?

　? Deformed (B(E2))

Deformed (Ex(2+))

RCNP

• 32Ne : Ex (2+ )32Ne, 33Na + C 32Ne + g + X

RIBF DayOne experiment

• 29F : Ex (Jπ ),30Ne + C 29F + g + X

P. Doornenbal and H. Scheit et al., in preparation

Phys.Rev.Lett., 103:032501, 2009.

RCNP

Phys.Rev.Lett., 103:032501, 2009.

2+ states in 32Ne

RCNP Further south, south of 30Ne ?

28O Unbound29F = 28O+p

28O

p

28O

p

RCNPExcited states in 29F

RCNP

Deformed (B(E2))

Deformed (Ex(2+))

South of Island-of-Inversion ?

RCNPEast of Island-of-Inversion

?

Deformed (B(E2))

Deformed (Ex(2+))

RCNP

• 36,38Mg : Ex (2+), Ex (4+)

37Al + C 36Mg + g + X39Al, 40Si + C 38Mg + g + X

• 36,38Mg : B(E2;0+2+1)

Coulex (38Mg+Pb) s B(E2)

P. Doornenbal and H. Scheit et al., in preparation

RCNP2+ state in 36,38Mg P. Doornenbal, H. Scheit et al.

C(37Al, 36Mg*)

C(37Al, 36Mg*)

C(40Si, 38Mg*)

C(39Al, 38Mg*)

RCNP2+ state in 36,38Mg P. Doornenbal, H. Scheit et al.


?

Deformed (B(E2))

Deformed (Ex(2+))


Deformed (B(E2))

Deformed (Ex(2+))

RCNPNorth-East of Island-of-Inversion

Deformed (B(E2))

Deformed (Ex(2+))

　?

RCNPSpherical or deformed ? from R4/2

Deformed (B(E2))

Deformed (Ex(2+))N

A

R(4

/2)

Ex (M

eV)

?

?2+

4+

Si isotopeS isotope

R(4

/2)

Ex (M

eV)

2+

4+

Shape Coex.,C. Force et al.PRL 105, 2010.


Deformed (B(E2))

Deformed (Ex(2+))


Deformed (B(E2))

Deformed (Ex(2+))

　

?

RCNPWhat we know about 42Si.

b-decay experimentShort half-life Large deformation (possibly oblate), comparing with QRPA calculation.

S.Grevy et al., Phys. Lett. B 594, 252 (2004).

Mass measurementDeformed/Spherical?

B.Jurado et al., Phys. Lett. B 694, 43 (2007).

NSCL case A substantial Z=14 subshell

closure

J.Fridmann et al., Phys. Rev. C 74, 034313 (2006)

GANIL case Well-deformed oblate rotor

B.Bastin et al., Phys. Rev. Lett. 99, 022503 (2007).

Two-proton removal reactions, 44S 42Si

RCNP

• Ex of 2+ and (4+) states in 38,40,42Si40S + C 38Si + g + X 44S + C 40Si + g + X44S + C 42Si + g + X

S. Takeuchi and M. Matsushita et al. in preparation

RCNP42Si - g single spectrum -

44S + C 42Si + g + X

GANIL exp. : 770(19) keVB.Bastin et al., Phys. Rev. Lett. 99, 022503 (2007).

We confirmed g line observed at GANIL.

RCNP42Si - g single spectra -

g ray (2+0+): 742(8) keVnew lines:

1431(11) keV2032(9) keV2357(15) keV

*Widths are fixed to simulated values.

44S + C 42Si + g + X

RCNP

*Widths are fixed to simulated values.

44S + C 42Si + g + X

42Si - g-g spectra -

1431 keV

2032 keV ?

742 keV

2032 keV ?

742 keV

0+

2+1431 ke

V

Partner of 742 keV1431 keV2032 keV?

Partner of 1431 keV742 keV2032 keV?

?1431 keV

0 keV

2173 keV(4+)R4/2 = 2.9

RCNP

Gate on 1079keV

1079(6)

2210 : This Work( Ex(4+) )

Gate on 1079keV

Spectroscopy of 38Si and 40Si

Gate on 988keV

634(7)988(6)

1544(8) : This Work(4+2+)

40S + C 38Si + X + γ 44S + C 40Si + X + γ

RCNP

Gate on 1079keV

1079(6)

2210 : This Work( Ex(4+) )

Gate on 1079keVGate on 988keV

634(7)988(6)

1544(8) : This Work(4+2+)

40S + C 38Si + X + γ 44S + C 40Si + X + γ

38Si

1084

1126

1.08

2.21

2+

(4+)

40Si

988

1544

634

0.99

(1.62)

(4+)

2+

2.53

Spectroscopy of 38Si and 40Si

RCNP42Si: well deformed

N=28 isotones

A

ZR

(4/2

)E

x (M

eV)

Z=14 isotopes

N

A

R(4

/2)

Ex

(MeV

)

2+

4+

2+

4+

R(4/2) = 2.9336Si: ref: X.Liang et al., PRC74,014311(2006)46Ar: ref: Zs.Dombradi et al., NPA 727(2003)19544S: ref: D.Santiago-Gonzalez et al., PRC 83,061305R(2011)

RCNPNorth East of Island-of-inversion

Deformed (B(E2))

Deformed (Ex(2+))

　

?

RCNP

Deformed (B(E2))

Deformed (Ex(2+))

North East of Island-of-inversion

Potential Energy Surface

s1/2

proton

neutronf7/2d3/2

d5/2

full

Tensor force removedfrom cross-shell interaction

Strong oblateDeformation

Otsuka, Suzuki and Utsuno,Nucl. Phys. A805, 127c (2008)

exp.

4214Si28

42Si

Other calculations (RMF, Gogny)show oblate shape.

42Si 2+: Bastin, Grévy et al., PRL 99 (2007) 022503

(4+) ： RIBF data 2011doublymagic ?

Z =14

p3/2N =28

repulsiveattractive

Otsuka-san’s talk (Wed)

RCNP

T.Otsuka et al., NPA 805 (2008) 127c

-- without tensor force spherical min.-- with tensor force oblate min.

Systematics of the 2+ and 4+ states in Si

Present exp.

RCNP

• 2008 DayOne 　 with 48Ca32Ne, 31,33Na

H. Scheit, P. DoornenbalPhys.Rev.Lett., 103:032501, 2009./Phys.Rev. C, 81:041305, 2010.

• 2010 48Ca campaign~42Si S. Takeuchi, M. MatsushitaA>36Mg P. Doornenbal, H. Scheit~Al, P David Steppenbeck

33Mg D. Bazin

• 2011 U campaign (~3 pnA)~132Sn H. Wang, NA

• 2012 Xe campaign~10xSn P. Doornenbal et al.

A. Obatelli et al.,

In-beam g-ray spectroscopy at RIBF

RCNP

Nov07 Spiral2

Approved γ-ray spectroscopy experiments at BigRIPS

86Kr/136Xe/238U 1pμA

Calculation uses•86Kr + Be Fragmentation EPAX2•136Xe + Be Fragmentation EPAX2•238U + Be Fragmentation EPAX2

Fission DATA@GSI (limited)•238U + Pb Fragmentation EPAX2

Fission ABLABRA

N=20 N=28

N=50

N=82

N=126

Z=20

Z=28

Z=50

Z=82

r-process

86Kr/136Xe/238U 1pμA

RCNPNuclei around 132Sn:Te, Sn beam fragmentation

Z

52

48

50

44

54

46

2.4 2.5 2.6 2.7 A/Q

130Sn

134Te

130Cd

124Pd Pd

Cd

Sn

Te

Particle Identify of Ejected Fragmentation

Wang He, NA et al.

RCNP

Wang He, NA et al.

132Te 130Sn

g-ray peaks are clearly observed

RCNPCollaborators

RCNP: N. AOI

RIKEN: P.DOORNENBAL, S. TAKEUCHI, M. MATSUSHITA, H. WangJ.LEE, L.KUOANG, D.STEPPENBECK, W.HE, T.MOTOBAYASHI, H.SAKURAI, H.BABA, M.TAKECHI, Y.TOGANO, K.YONEDA

Darmstadt H.SCHEIT TITech: N.KOBAYASHI, G.LEE, Y.KONDO, T.NAKAMURA, T.SAKO, K.TAKAHASHICNS: S.GO, E.IDEGUCHI, S.MICHIMASA, S.OTA, S.SHIMOURATU Munchen: R.GERNHAEUSER, C.HINKE, R.KRUCKEN, K.STEIGERANL: C.HOFFMANGANIL: L.CACERESFrankfurt/GSI: T.L.BLEISIN2P3: S.GREVY, A.MATTALBNL: H.CRAWFORD, P.FALLON, M.PETRI,LPC CAEN: J.GIBELINNSCL: D.BAZIN, R.WINKLERRICHMOND: R.HUGHESYORK: D.JENKINS

RCNP

Deformed (B(E2))

Deformed (Ex(2+))

Extended view around Island-of-inversion

in-beam gamma-ray spectroscopy at ribf

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