SUNFLOWER --- In-beam Gamma-ray spectroscopy at RIBF He Wang RIKEN - - PowerPoint PPT Presentation

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SUNFLOWER --- In-beam Gamma-ray spectroscopy at RIBF He Wang RIKEN - - PowerPoint PPT Presentation

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SUNFLOWER --- In-beam Gamma-ray spectroscopy at RIBF He Wang RIKEN Nishina Center The 9 th Japan-China Joint Nuclear Physics Symposium (JCNP 2015), November 7-12, 2015, Osaka University Content Introduction to SUNFLOWER Experiment

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SLIDE 1

He Wang

The 9th Japan-China Joint Nuclear Physics Symposium (JCNP 2015), November 7-12, 2015, Osaka University

RIKEN Nishina Center

SUNFLOWER

  • -- In-beam Gamma-ray spectroscopy at RIBF
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SLIDE 2

Content

  • Introduction to SUNFLOWER
  • Experiment details
  • Selected results
  • Perspective
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SLIDE 3

Spectroscopy of Unstable Nuclei with Fast and sLOW beam Experiments at RIBF

SUNFLOWER

http://www.nishina.riken.jp/collaboration/SUNFLOWER

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SLIDE 4
  • The collaboration offers a forum of discussion and information exchanges.
  • -- Proposals may be amended after consulting with the SUNFLOWER

members in advance of the PAC meeting.

  • Arranges the tasks and resources necessary to accomplish experiments.
  • -- The spokes persons of proposed experiments may ask

members of SUNFLOWER to collaborate.

  • Provides technical information and consults regarding the utilization of

non-standard detectors.

  • Coordinates research programs and equipment use.
  • -- Arranges experimental campaigns. Mediates between conflicting

experiments when similar subjects are proposed.

  • Discusses the strategy of detector developments.

Function

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SLIDE 5

2009 48Ca 2008 Dayone/48Ca 2011 238U 2012 124Xe/70Zn 2013 238U

SUNFLOWER experiments

32Ne

  • H. Scheit, P. Doornenbal

PRL103(2009)032501

31,33Na H. Scheit, P. Doornenbal

PRC81(2010)041305

2010 48Ca

32Mg

  • K. Li, H. Scheit

CPL29(2012)102301, PRC92(2015)014608 ~42Si

  • S. Takeuchi, M. Matsushita

PRL109(2012)182501

36,38Mg P. Doornenbal, H. Scheit

PRL111(2013)212502

29F

  • P. Doornenbal

~Al, P

  • D. Steppenbeck

33Mg

  • D. Bazin

40Mg test P. Fallon, H.L.Crawford

PRC89(2014)041303

31Ne, 22C T. Nakamura, N. Kobayashi

PRL103(2009)262501,PRL112(2014)142501,PRC86(2012)054604

78Ni

  • K. Yoneda

~132Sn HW, N. Aoi PRC88(2013)054318,PTEP2014:023D02,CPL30(2013)042501

10xSn

  • A. Obertelli, P. Doornenbal

PLB743(2015) 451, PRC90(2014)061302

54Ca

  • D. Steppenbeck, S. Takeuchi

Nature 502(2013)207, PRL114(2015) 252501

2014 238U

74Ni

  • G. de Angelis

130Cd

HW, N. Aoi SEASTAR P. Doornenbal, A. Obertelli PRL115(2015)192501

2015 238U/78Kr

73,77Cu E. Sahin, Z.Y. Xu, G. de Angelis 136Te A. Jungclaus, P. Doornenbal

SEASTAR P. Doornenbal, A. Obertelli

70,72Kr W. Korten, P. Doornenbal

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SLIDE 6

2015/9/30 4th SUNFLOWER Workshop Osaka University Osaka, JAPAN 2014/9/15,16 3rd SUNFLOWER Workshop University of Tokyo Tokyo, JAPAN 2013/9/10 SUNFLOWER Workshop TU Darmstadt Darmstadt, GERMANY 2013/2/20 SUNFLOWER - In-beam gamma and MINOS mini-WS RIKEN Nishina Center, Wako, JAPAN SUNFLOWER workshops

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SLIDE 7

RI Beam Factory

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SLIDE 8

Primary beam intensity

Heavy ion beams (up to U) of 345AMeV at SRC Fast RI beams by projectile fragmentation and U-fission at BigRIPS

  • H. Okuno, et al., Prog. Theor. Exp. Phys. (2012) 03C002.

Primary beam intensity records

35 pnA U @ Oct. 2015

78Kr

RI Beam Factory

Superconducting Ring Cyclotron (SRC)

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SLIDE 9

T.Ohnishi, T.Kubo et al., JPSJ 77 (2008) 083201. T.Ohnishi, T.Kubo et al., JPSJ,79 (2010) 073201.

New isotope search at RIBF

More than 120 species

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SLIDE 10

BigRIPS/ZeroDegree

RI Beam Factory : BigRIPS and ZeroDegree

Experiment

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SLIDE 11

Reacted beam beam target

  • Fast beam and thick target
  • - Increased luminosity
  • - Event-by-event identification
  • - Gamma-ray spectroscopy on the exotic nuclei

Nuclear reactions with Fast beams

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SLIDE 12

BigRIPS ZeroDegree

Production target

Experimental setup

Tagging

Primary beam Reacted beam beam target

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SLIDE 13

BigRIPS separator 1st stage

BigRIPS fragment separator

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SLIDE 14

BigRIPS separator 2nd stage

BigRIPS fragment separator

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SLIDE 15

F8 F11

ZeroDegree spectrometer

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SLIDE 16

BigRIPS ZeroDegree

Production target

238U

Experimental setup

DALI2 Array

Tagging Ejectile PID@ZeroDegree Atomic number Z Mass-to-charge ratio A/Q Projectile PID@BigRIPS Atomic number Z Mass-to-charge ratio A/Q

55Sc54Ca

2nd target

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SLIDE 17

ZeroDegree Spectromete r

DALI2 Array

F8 Inside

Experimental setup@F8

  • S. Takeuchi, et al., NIMA, 763:596, 2014.

186 NaI(Tl) detectors θ coverage 11 to 165 degrees

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SLIDE 18

Energy (keV) Emission angle of g rays 20° 160°

32Mg(p,p’) b ≈ 0.3 H.Hasegawa, Master’s thesis, Rikkyo Univ., 2003

(a) Laboratory frame (b) Projectile frame

In-beam γ spectroscopy

Doppler correction Ecm = γElab(1- b cos(θlab))

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SLIDE 19

In-beam γ spectroscopy

Δθ = 8o b = 0.6 Δb =10% ΔEint=7.5% Doppler correction Ecm = γElab(1- b cos(θlab)) Efficiency ≈ 20% ΔE/E ≈15% (FWHM) (@1 MeV γ-ray, b ≈ 0.6)

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SLIDE 20

Collectivity: B(E2) Type of Collectivity: Ex(2+) / Ex(4+) Single Particle level: Ex, Jπ

Region of Interest

Island of Inversion N=34 in 54Ca Magic number ~100Sn ~132Sn ~78Ni

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SLIDE 21

20 8 28

34Mg 30Ne 32Mg

Island of Inversion

32Mg: T. Motobayashi et al., PLB 346, 9 (1995). 31F: H. Sakurai et al., PLB 448, 180 (1999). 34Mg: K. Yoneda et al., PLB 449, 233 (2001). 30Ne: Y. Yanagisawa et al., PLB 556, 84 (2003).

N=28 in Mg(Z=12) and Si(Z=14)

Ex(2+) is an indicator of “magicity”

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SLIDE 22

20 8 28

34Mg 32Mg

Island of Inversion

Energy (keV) 1000 2000 3000 Counts / 25 keV 20 40 60 80 Mg

38

<4

g

M

656(6) 1360(20)

20 40 60 Mg)

38

Si,

40

C(

g

All M 1000 2000 20 40 60 Mg)

38

Al,

39

C(

g

All M

Counts / 25 keV 1 10

2

10

<3

g

Mg), M

36

Al,

37

C(

662(6) 1370(20)

1000 1 10

2

10

g

All M

V Energy (keV) 1000 2000 3000 4000 10

36,38Mg:

  • P. Doornenbal, et al.,

PRL 111, 212502 (2013).

12 14 10

36Mg 38Mg

48Ca primary beam~70 pnA 40Si: 3000 pps, 230 MeV/u 39Al: 110 pps, 220 MeV/u

F8 target: nat.C, 2.54 g/cm2

N=28 in Mg(Z=12) and Si(Z=14)

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SLIDE 23

20 8 28

34Mg 32Mg

Island of Inversion

Energy (keV) 1000 2000 3000 Counts / 25 keV 20 40 60 80 Mg

38

<4

g

M

656(6) 1360(20)

20 40 60 Mg)

38

Si,

40

C(

g

All M 1000 2000 20 40 60 Mg)

38

Al,

39

C(

g

All M

Counts / 25 keV 1 10

2

10

<3

g

Mg), M

36

Al,

37

C(

662(6) 1370(20)

1000 1 10

2

10

g

All M

V Energy (keV) 1000 2000 3000 4000 10

36Mg 38Mg

12 14 10

42Si

48Ca primary beam~70 pnA 44S: 40000 pps, 210 MeV/u

F8 target: nat.C, 2.54 g/cm2

42Si:

  • S. Takeuchi et al.,

PRL 109, 182501 (2012).

N=28 in Mg(Z=12) and Si(Z=14)

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SLIDE 24

(MeV)

x

E 1 2 3 4 5

1 +

4

1 +

2

Si

1 +

2 Si

1 +

4 Mg

1 +

2 Mg

1 +

4 SDPF-M SDPF-MU SDPF-U-MIX 3DAMP+GCM

Neutron Number N 20 22 24 26 28

4/2

R 2 2.5 3

Si

4/2

R Mg

4/2

R

  • Smooth transition in Si
  • Almost identical in 34,36,38Mg

Sound magicity in Si @ N = 20 Large collectivity in Si and Mg @ N~28 Magicity disappeared in Mg @ N = 20

Ex(2+) [MeV] R4/2

Mg Si

34Si 32Mg 42Si

Magicity disappeared in Si @ N = 28

N=28 in Mg(Z=12) and Si(Z=14)

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SLIDE 25

Collectivity: B(E2) Type of Collectivity: Ex(2+) / Ex(4+) Single Particle level: Ex, Jπ Island of Inversion

  • D. Steppenbeck, S. Takeuchi, et al.,

Nature(London), 502:207, 2013.

54Ca

Appearance of new magic number

N=34 in 54Ca

70Zn primary beam ~100 pnA

Be(55Sc,54Ca*), Be(56Ti,54Ca*) F8 target: 9Be, 1.85 g/cm2 124 pps/pnA 56Ti 12 pps/pnA 55Sc

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SLIDE 26

Collectivity: B(E2) Type of Collectivity: Ex(2+) / Ex(4+) Single Particle level: Ex, Jπ Island of Inversion N=34 in 54Ca Magic number ~100Sn ~132Sn ~78Ni

Nuclear structure around 100Sn and 132Sn

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SLIDE 27
  • Constancy of Ex(2+)
  • A high 2+ state at N=82
  • Sudden drop at N=84

N=82 N=50

Nuclear structure in light and heavy Sn

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SLIDE 28
  • Neutron contribution dominant in the first 2+ state
  • Reduction of neutron collectivity from 112Sn to 104Sn

0+ → 2+

HFB+QRPA with Gogny D1M interaction, no model space limitation

M.Martini, S.Peru and M.Dupuis, PRC 83, 034309 (2011)

0+ → 2+

  • A. Corsi et al., PLB 743, 451 (2015)

Neutron driven collectivity

104Sn(p,p’)

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SLIDE 29
  • Constancy of Ex(2+)
  • A high 2+ state at N=82
  • Sudden drop at N=84

N=82 N=50

Nuclear structure in light and heavy Sn

What is the role of neutron in the neutron-rich Sn isotopes?

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SLIDE 30

Pd Ag Cd In

70 76 80 82 84 86

Sn Sb Te I Xe

78 74 72

2+ state known 2+ state unknown

Gamma-ray spectroscopy in 136Sn

136Sn

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SLIDE 31

137Sb

A-1 A+3 A

Ejectile PID@ZeroDegree Projectile PID@BigRIPS

Particle Identification

9Be(137Sb,136Sn)

136Sn50+ and 133Sn49+

ΔA/Q=136/50-133/49=5.7x10-3 A/Q resolution 2.7x10-3 (rms)

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SLIDE 32

Particle Identification

9Be(137Sb,136Sn)

Q=Z-1 Q=Z

136Sn50+

Charge states ID by TKE Ejectile PID@ZeroDegree

136Sn50+ and 133Sn49+

ΔA/Q=136/50-133/49=5.7x10-3 A/Q resolution 2.7x10-3 (rms)

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SLIDE 33

The first 2+ state in 136Sn

One-proton removal reaction

HW, N. Aoi et al., Prog. Theor. Exp. Phys. 2014, 023D02(2014)

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SLIDE 34

Systematics of Ex(2+)

  • Z=50 magicity in N=86 isotones
  • Constant Ex(2+) beyond N=82  Seniority scheme
  • Asymmetric Ex(2+) pattern around N=82

~500 keV

Present work Mass number A Mass number A

PRL113, 132502 (2014)

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SLIDE 35

Δ(3)(N)=(-1)N[B(N-1)+B(N+1)-2B(N)]/2

Possible reason

N<82 N>82

  • J. Hakala, et al., PRL 109, 032501(2012)

Reduction of pairing?

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SLIDE 36
  • Beam intensity will continue increasing

 Expansion of region

  • More elaborate measurements

 Higher excited states  Low energy reactions (OEDO)

  • New detectors

LaBr3 based Ge based (tracking array?)

Future

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SLIDE 37

Shell Evolution and Search for Two-plus Energies At the RIBF (SEASTAR) – a RIKEN Physics program

Spokespersons: P. Doornenbal (RIKEN), A. Obertelli (CEA, RIKEN) You are welcome to the SEASTAR collaboration! http://www.nishina.riken.jp/collaboration/SUNFLOWER/experiment/seastar/index.html

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SLIDE 38
  • Many experiments are already proposed
  • In-beam γ-ray spectroscopy with various reactions
  • Experimental data obtained so far are very

promising

  • -- Nuclear structure study for the exotic nuclei
  • Future plan

Summary

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SLIDE 39

Collaborators

36,38Mg, 42Si

  • P. Doornenbal, H. Scheit, S. Takeuchi , N. Aoi , K. Li , M. Matsushita,
  • D. Steppenbeck, H. Wang, H. Baba, H. Crawford, C.R. Hoffman, R. Hughes,
  • E. Ideguchi, N. Kobayashi, Y. Kondo, J. Lee, S. Michimasa, T. Motobayashi,
  • H. Sakurai, M. Takechi, Y. Togano, R. Winkler, and K. Yoneda

RIKEN Nishina Center, Peking University, Rikkyo, LBNL, ANL, Richmondm, CNS, NSCL/MSU

  • D. Steppenbeck, S. Takeuchi, N. Aoi, H. Baba, N. Fukuda, S. Go,
  • P. Doornenbal, M. Honma, J. Lee, K. Matsui, M. Matsushita, S. Michimasa,
  • T. Motobayashi, D. Nishimura, T. Otsuka, H. Sakurai, Y. Shiga, N. Shimizu,

P.-A. Söderström, T. Sumikama, H. Suzuki, R. Taniuchi, Y. Utsuno,

  • J. J. Valiente-Dobón, H. Wang and K. Yoneda

CNS, RIKEN, RCNP, University of Aizu, University of Tokyo, Tokyo University of Science, Tohoku University, Japan Atomic Energy Agency, Legnaro National Laboratory, Peking University

54Ca

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SLIDE 40
  • A. Corsi. A.Obertelli, L.Audirac, S.Boissinot, A.Gillibert, V.Lapoux, E.Pollacco,

C.Santamaria, P.Doornenbal, M.Matsushita, D.Steppenbeck, S.Takeuchi, H.Wang, N.Aoi, H.Baba, K.Matsui, T.Motobayashi, D.Nishimura, S.Ota, H.Sakurai, H Shiga,

  • R. Taniuchi, M.Dupuis, F.Lechaftois, M.Martini, S.Péru

CEA-Saclay, RIKEN, CNS, RCNP, CEA/DAM/DIF Arpajon

10xSn

136Sn,132Cd

  • H. Wang, N. Aoi, S. Takeuchi, M. Matsushita, P. Doornenbal, T. Motobayashi,
  • D. Steppenbeck, K. Yoneda, H. Baba, Z. Dombrádi, K. Kobayashi, Y. Kondo,
  • J. Lee, H. Liu1, R. Minakata, D. Nishimura, H. Otsu, H. Sakurai, D. Sohler,

Y.L. Sun, Z.-Y. Tian, R. Tanaka, Z. Vajta, Z.-H. Yang, T.Yamamoto, Y.-L. Ye, and R. Yokoyama Peking University, RIKEN Nishina Center, RCNP, Osaka, CNS, Tokyo, Rikkyo, TITech, Tokyo University of Science

Collaborators

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SLIDE 41

Thank you.