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Study of decay properties and synthesis of heavy elements�

Shunji NISHIMURA ( RIKEN Nishina Center)

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Where are we from?�

NASA WMAP�

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Mg"234)*+ Si"56� Fe"7 F"89� Zn":; Rb"(<=*+ Sr">0?-@*+ Br"A� Pb"; Cu"B

CD�ElementEprotonFZG�Al"H(�I*+

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Atomic number"EZG�

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J.J.Cowan, C.Sneden (2006�G�

1st Stars �

Elements�

Stellar nucleosynthesis�

BigBang nucleosynthesis�

113�113heavy elements !?�

11 Greatest Unanswered Questions XPhysicsY�

Discover Vol.22 No. 02 February 2002

1. What is dark matter? 2. What is dark energy? 3. How were the heavy elements from iron to uranium made? 4. Do neutrinos have mass? 5. Where do ultrahigh-energy particles come from? 6. Is a new theory of light and matter needed to explain what happens at very high energies and temperatures? 7. Are there new states of matter at ultrahigh temperatures and densities? 8. Are protons unstable? 9. What is gravity? 10. Are there additional dimensions? 11. How did the universe begin?

gy 3. How were the heavy elements from iron to uranium made? 4 D i h ?

Mass A"= proton num.EZ)Zneutron num.ENG

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(log ε) Sneden, J.J. Cowan, Science Vol. 299 (2003�G�

William Fowler E[�\]G�

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(Steward observatory)��

Wanajo�

Supernovae�� Neutron-star merger?�

Mystery of site: Where �

How were heavy elements created in the universe?�

r-process peaks (A~80, 130, 195) are associated to very neutron-rich magic nuclei N = 50, 82, 126 �

Origin of Heavy Elements (Pt, Th, U…) Supernovae vs Neutron Star Merger�

Type II Supernovae��

NASA/JPL-Caltech/O.Krause (Steward observatory)�

S. Wanajo�

- Mechanism of Explosion.. ? - Lack of Neutrino, Neutron F Ye < 0.5?�

- Extremely neutron-rich nuclei - Very Rare to have two neutron stars close together. - Not possible in 1st stars.

Neutron star merger ?�

Very Neutron-Rich Nuclei (Far from the stability..)�

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Nuclear masses Nuclear decay Nuclear shell structure v-induced processes�

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Heavier A�neutron � proton�Neutron

capture N+1�

Beta-decay�

Neutron � Proton�photodisintegration�

s-process & r-process (slow vs rapid)�

Langanke Lecture�Sneden et al. (2008)�

Cycle in Universe�

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Eu/Fe abundances as a function of [Fe/H] metalicity�

r-process enhanced star�

Significant [Eu/Fe] abundance scatter at low metalicity�

Old star�

C. Sneden, J.J. Cowan, R. Gallino, Annu. Rev. Astro. (2008)�

Abundance Patterns in Galactic Halo Stars ( The origin of about half of elements > Fe )�

Heavy elements in oldest stars (Z > 56) � Closely match the Solar System (SS) r-process pattern.

Swesty, Calder, Wang�

Open question: Where does the r process occur ? J.J.C

owan C

.Sneden, Nature 440 (2006)�

� Te (Z=52) data. I.U

. Roederer, A

pJ L 747 (2012)�Key: We need properties of most neutron-rich nuclei.

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Superheavy elements"(RIKEN)�

Element 113 � Naming? �

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RIBF & Decay Station�

Survey of Nuclear Properties (Decay Spectroscopy)�

keV��First E(2+) for even-even nuclei�

- Excited states : E(2+), ..

- Isomeric states

- Qβ , EC

- Decay curve : T1/2

- Beta-delayed neutron/proton

- New isotopes

- New magic number ? - Disappearance? - Shell quenching? - Deformation?

D.Steppenbeck et al. In-beam gamma (RIBF)

54Ca �

Decay curve and T1/2�

Likelihood method with 10ms bins (0 – 5 sec) Free parameters for fitting - Background … ~ 0.5 cps - Neutron emission Probability (Pn) - Detection efficiency (ε) … 40% - 80% Consistency check - Monte Carlo Simulation / beta-delayed gamma

T1/2

98Rb decay�

daughter and granddaugter ( β & β -n branches )�

background�

Very Neutron-Rich Nuclei (Far from the stability..)�

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SN, PRL 106 (2011)�

Zr and Nb decay faster than expected by FRDM+QRPA ( T1/2 : 1/2 ~ 1/3 )�

Upgrade : 2009 � 2012-2013�

U-beam intensity - 0.2 pnA � ~ 10 pnA … x 50 times

Gamma-ray detector - 4 Clover detectors � 12 Cluster detectors (Det. Eff. ~ 8 % at 1 MeV) … x 10 times ( � gamma-gamma coincidence … x 100 times ) Beta counting system

- 16 x 16 pixels x 7 layers = 1792 pixels � 40x60 pixels x 8 layers = 19200 pixels

… x 10 times

Decay spectroscopy of key nuclei relevant to r-process nucleosynthesis�

Cluster Ge-detectors (gamma-ray detection)�High resolution, High efficiency gamma-ray detector! ( x 10 times)�

Beta-counting system inside EURICA

World highest efficiency detectors E1 months � 40 minutes G� Ï"�

World high intensity RI beam [||| times�

Beta-decay half-lives, etc.. �

WAS3ABiFbeta-ray detection�

gamma-ray�

RI Production and Decay Spectroscopy�

238U, 124Xe @ 345 MeV/u �

9Be�

238U … Intensity = 5 – 12 pnA 124Xe … 32 – 38 pnA 78Kr … 200 - 300 pnA

30 pnA�=== 55 – 12 pnAAA AA32 333888 A

Beta-counting system: WAS3ABi in EUIRCA (Wide-range Active Silicon-Strip Stopper Array

for Beta and ion detection) �

(a)� (b)� (c)�

(d)�

RIKEN/IBS/TU-Munchen�

Heavy-ion … ~ 6 GeV ~ (Nov. / 2014) Beta-ray … 20 keV ~ 3 MeV High segmentation … 60 x 40mm2, 1mm strips

Up to 16,000 pixels Qbeta …. Plastic scintillator or SSSD x 10 Fast timing … Plastic scintillators

DSSSD (Univ. York)�

Decay Spectroscopy in the vicinity of double magic 78Ni

(Z=28, N=50)�Z.M.Niu, PLB 723 (2013)�

[ History of 78Ni ]��

+100�-60�

- 1997 Identified as new isotope (3 events) M.Bernas et al., PLB415 (1997) -  2005 Beta-decay half-life (11 events) T1/2 ~ 110 ms T.Hosmer et al., PRL94 (2005)

RIBF: Decay Experiment around 78Ni region�

87Ga��

88Ge�

Half-lives unknown�

78Ni�

~ 12 k of 78Ni produced at the RIBF. Low production yield of 79Ni (78Ni + neutron)�

Implantation rate = 20 ~ 50 pps�A/Q�

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Spokesperson : SN / Niikura�

80Ni��77Co�

83Cu�

New isotopes (7 Candidates)�

85Zn�

75Fe�

73Mn�

78Ni beta-decay half-life�

Gated on β-delayed γ�

Decay spectra obtained in WAS3ABi. What about N=51 (79Ni)? Z=27 (77Co)?

78Ni�

?�

79Ni�

Z.Y.Xu et al. Phys. Rev. Lett. 113 (2014) 032505�

T1/2 = 122.2 ±5.1 ms

Hos

mer

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L (2

006)� T1/2 = 110 ms +100�

-60�

Beta-decay half-lives beyond 78Ni�

77Co�

78Ni��

79Ni� o

78N

Shorter T1/2 beyond 78Ni � Pronounced in Z = 28, N=50 � 78Ni is double magic nuclei !?

Z.Y.Xu, PRL (2014)�

Neutron detection system�

I.N.Borzov Phys. Rev. C71 (2005) 065801

Rapid increase of neutron emission prob. around 78Ni.

Decay properties around double magic 132Sn

( Z=50, N=82 )�

133Cd

J. Hakala et al., Phys. Rev. Lett. 109 (2012) 032501

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New isomers around - 126,128Pd, 136,138Sn region�

* ***

110 Half-lives measured

masses

T1/2

Decay Spectroscopy around A = 100 ~ 145�Two EURICA data sets: G.Simpson/A.Jungclaus & H.Watanabe/G.Lorusso �

U-beam: 8 – 10 pnA ~ Two weeks�

Known T1/2��

Decay Spectroscopy around A = 100 ~ 145�

A.Jungclaus, PRL99, (2007) No evidence for shell quenching�

130Cd�

126Pd�

� No evidence for shell-quenching in 128Pd…. �

128Pd�

128Pd (N=82)�126Pd (N=80)�

H. Watanabe et al., PRL111 (2013)

118Tc�

Decay Spectroscopy around A = 100 ~ 145�

Urban, EPJ A 20, 381 (2004)�

?�

P.-A. Söderström, et al. Phys. Rev. C 88, 024301 (2013)

To be confirmed by γÐγ coin.�

T.Sumikama, PRL106�

116Tc�

118Ru�116Ru�

Decay Spectroscopy around A = 100 ~ 145�

138Sn�136Sn�

G. Simpson, G.Gey, A.Jungclaus .. Phys. Rev. Lett. 113, 132502 (2014)

136Sn 138Sn 134Sn

Very short T1/2 !��

136Sn

138Sn

Identification of milisecond isomeric states via detection of conversion electrons�

129Cd�

J.Taprogge, A.Jungclaus et al. Phys. Lett. B 738 (2014) 223.�

126Pd�

H.Watanabe et al. Phys. Rev. Lett. 113 042502 (2014)�

ÑÒ�ÓÔ"ÕÏÖÒÔ×Ø"ÙÔÚÔ×: E(2+) �

15 E(2+) are expected from EURICA ! And more … �

Z.Patel et al. PRL 113, 0262502 (2014)�

166Gd�

164Sm�

β-decay half-lives on r-Process path�

130Cd�

52 new half-lives!

110 Half-lives from Very Neutron-Rich Rb to Sn�G.Lorusso et al., PRL 114, 192501 (2015)��

40 new half-lives ! �

r-process abundance with new T1/2 (RIBF)�

r-process universality and duration of r-process�

128,130Te�127I�

128Pd�

130Cd�

127Rh�

129Ag�

NA

SA/JPL-C

altech/O.K

rause (Steward observatory)�

Supernovae explosion�

Duration of r-process

128 133333300000000128 1 TTTTTTTTeeeeeeee

128Pd

131313131313131300011111111 Cd

1271 Rh

1291 Ag

3128,1

Universality of r-process elements (Z > 56)�

International collaboration�

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J. Agramunt, P. Aguilera, T. Alharbi, A. Algora, G. Angelis, N. Aoi, P. Ascher, R. Avigo, H.Baba, C. Borcea, A. Boso, A.M. Bruce, R.B. Cakirli, F.L.Bello Garrote, G. Benzoni, J.S.Berryman, R. Berta, B. Blank, N. Blasi, A. Blazhev, P. Boutachkov, S. Bonig, A. Bracco, F. Browne, F. Camera, R.J. Carroll, S. Ceruti, I. Celikovic, K.Y. Chae, J. Chiba, L. Coraggio, A. Covello, F.C.L. Crespi, J.-M. Daugaus, R. Daido, P. Davis, M.C. Delattre, F. Diel, F. Didiejean, Zs. Dombradi, P. Doornenbal, F. Drouet, H.J. Eberth, A. Estrade, Y. Fang, T. Faestermann, G. France, S. Franchoo, Y. Fujita, N. Fukuda, A. Gadea, E. Ganioglu, A. Gargano, W. Gelletly, M. Gerbaux, R. Gernhauser, G. Gey, J. Giovninazzo, S. Go, N. Goel, T. Goigoux, M. Gorska, A. Gottardo, H. Grawe, S. Grevy, C. Griffin, Vi. Guadilla, T. Hashimoto, S. Hayakawa, J. Henderson, C. Hinke, N. Hinohara, E. Ideguchi, S. Ilieva, N. Inabe, T. Ishigaki, T. Isobe, Y. Ito, D.G. Jenkins, P.R. John, H.S. Jung, A. Jungclaus, T. Kajino, D. Kameda, H. Kanaoka, Y. Kanke, Y. Kawada, G.D. Kim, Y.-K. Kim, G. Kiss, Ka. Kobayashi, K. Kobayashi, M. Kobayashi, N. Kobayashi, K. Koehler, I. Kojouharov, T. Komatsubara, F.G. Kondev, Z. Korkulu, Y. Kondo, M. Kowalska, T. Kroll, R. Krucken, T. Kubo, S. Kubono, M. Kurata-Nishimura, T. Kurtukian Nieto, N. Kurz, I. Kuti, Y.K. Kwon, G.J. Lane, S. Lalkovski, G. Lane, E. Lee, J. Lee, P. Lee, S. Lenzi, M. Lewitowicz, Z. Li, J. Liu, T. Lokotko, G. Lorusso, G. Lotay, R. Lozeva, D. Lubos, C. Magron, F. Molina, I. Matea, K. Matsui, M. Matsushita, B. Melon, D. Mengoni, B. Meyer, S. Michimasa, T. Miyazaki, V. Modamio Hoybjor, S. Momiyama, C.-B. Moon, A. Montaner-Piza, A.I. Morales, P. Morfouace, S. Morimoto, K. Moschner, D. Mucher, E. Nacher, J. Nagumo, H. Naidja, T. Nakao, T. Nakatsukasa, D.R. Napoli, F, Naquvi, M. Niikura, H. Nishibata, S. Nishimura, I. Nishizuka, C. Nita, F. Nowacki, A. Odahara, K. Ogawa, H. Oikawa, R. Orlandi, S. Ota, T. Otsuka, H.J. Ong, S. Orrigo, M. Rajabali, J. Park, Z. Patel, A. Petrovici, F. Recchia, V. Phong, Zs. Podolyak, O.J. Roverts, L. Prochniak, P.H. Regan, S. Rice, E. Sahin, H. Sakurai, K. Sato, H. Schaffner, H.Scheit, P. Schury, C. Shand, Y. Shi, S. Shibagaki, T. Shimoda, Y. Shimizu, K. Sieja, L. Sinclair, G.S. Simpson, P.-A. Soderstrom, D. Sohler, I.G. Stefan, K. Steiger, D. Steppenbeck, K. Sugimoto, T. Sumikama, D. Suzuki, H. Suzuki, T. Tachibana, K. Tajiri, S. Takano, A. Tashima, H. Takeda, Man. Tanaka, Mas. Tanaka, Y. Takei, R. Taniuchi, J. Taprogge, K. Tajiri, T. Teranishi, S. Terashima, G. Thiamova, K. Tshoo, Zs. Vajta, J. Valiente Dobon, Y. Wakabayashi, P.M. Walker, H. Watanabe, A. Wendt, V. Werner, O. Wieland, K. Wimmer, J. Wu, Q. Wu, F.R. Xu, Z.Y. Xu, A. Yagi, S. Yagi, H. Yamaguchi, K. Yamaguchi, T. Yamamoto, M. Yalcinkaya, R. Yokoyama, S. Yoshida, K. Yoshinaga, G. Zhang�

[� countriesF _] collaborators�

2−10

1−10

1

10

210

310

410

510

610

710

810

910

N (number of neutrons)20 40 60 80 100

10

20

30

40

50

60

70

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N=

82

drip-line

R-Process Path

Ni78

Sn132Sn100

Ni48

Decay Spectroscopy at RIBF

Beta-decay half-lives (Published)

Surveyed (2009-2015)

U-beam238

(2012,2013)

U-beam238

(2012,2013)

U-beam238

(2013,2014)

Xe-beam

124

(2012,2013)

Xe-beam

124

(2013)

Kr-beam

78(2015)

(sec)

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In four years… (U-beam int. > 100 pnA!?)�

Several hundreds of new beta-decay half-lives � Significant contribution in nuclear structure and r-process nucleosynthesis.

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1

10

100

2008 2010 2012 2014 2016

pnA�

Year�

Beta-decay flow back to stability�

Beta-decay of isotopes : 127Rh, 128Pd, 129Ag, 130Cd (N=82) � Sn, Te�

FRDM + QRPA�

128Pd�

128Te�

BRIKEN Project (RIBF) Monster of 3He Detectors�

Very high efficiency neutron detector � Survey of beta-delayed multi-neutron & T1/2

r-Process path toward heavy region�RIKEN News 2015 Sep. �