China-Japan collaboration workshop on “Nuclear mass and life for unraveling mysteries of r-process” June 26-28, 2017

Experimental challenges relevant tor-process nucleosynthesis
Shunji NISHIMURA
RIKEN Nishina Center

EURICA Project (2012 – 2016)!"# spectroscopy•

BRIKEN Project(2016 – 2018?)- !"n"# spectroscopy•

Future Projects(2019 - …)
- CAITEN / NiGIRIWhere is the site of heavy elements ?
(r-Process Nucleosynthesis)
Type II Supernovae

Neutron star merger ?

NASA/JPL-Caltech/O.Krause(Steward observatory)- Mechanism of Explosion.. ?
- Lack of Neutrino, Neutron %Ye < 0.5?
- Strong magnetic field ?
N. Nishimura, T. Takiwaki, F.-K. Thielemann
Astrophys. J. 810 109 (2015)- Extremely neutron-rich nuclei- Very Rare to have two neutron stars
close together.
- Not possible in 1st stars !?

S. Wanajo

Origin of Heavy Elements
Supernovae vs Neutron Star Merger
r-process conditions:Ye, S, τ, EOS, …

Network calculation
with Nuclear Properties

Supernovae explosion?

J.J.Cowan C.Sneden, Nature 440 (2006)

Neutron star merger?

S. Wanajo

r-process abundance Z, AMass … r-proces path (n,γ)  (γ,n)
Half-lives … process speed/abundance
Delayed neutron emission & Fission… freeze-out path, odd-even
Nuclear Structure- Neutron Magic (N=50, 82, 126) ,Deformation, Quenching

Origin of Heavy Elements: Rare-earth

S. Goriely et al PRL 111, (2013)

C. Sneden et al.(2008)

decay rates, masses, fission, b-delayed neutron! " magic, deformation

Decay Spectroscopy at RIBF

EURICA Spectrometer at RIBF
238U

… 345 MeV/u; int. 5 – 12 pnA (now 50 pnA)

EURICA

Beta-counting system WAS3ABi
inside EURICA

gamma-ray

Identificationof RI

Primary Beam
(238U / 124Xe / 78Kr)
RI Beam

Production
TargetSeparationof RI

440 Exotic Isotopes Surveyed by EURICA Spectrometer
half-lifesecZ (number of protons)

EURICA Data( 2012 – 2016 )New Isotopes … 15

Delayed γ … 37

Beta-decay half-life … 234

Delayed neutron … 6

Isomer … 14

Proton emission … 38250

50

2828

440 isotopes in total
N (number of neutrons)

!-decay half-lives on r-process path

130Cd

110 half-lives(40 new T1/2)
G. Lorusso

Beta-decay Half-lives N = 82 " Feedback to the Theory

129Ag

132

T1/2 =162ms

125Tc

130Cd

126Ru

131

128Pd

127Rh

K.Langanke Phys. Scr. T152 (2013) 014011(Courtesy of G. Martines-Pinedo)

RIBF
EURICA

B.Pfeiffer et al.
(2001)

So call r-process waiting point nuclei (N=82)- r-process path- residual r-matter flow in freeze-out

Shell model ! ~ 25% shorter T1/2
Confirmed by R. Dunlop (2016, TRIUMF)
130Cd … T
1/2 = 126 (4) ms

110 Half-lives of Very Neutron-Rich Rb to Sn
40 new half-lives !

G.Lorusso et al.,PRL 114, 192501 (2015)SN
18 new half-lives ! PRL 106, 052502 (2011)r-process Abundance with New T1/2 (RIBF)
G.Lorusso et al., PRL (2015)
BeforeAfter new RIBF data
1st Peak
2nd Peakr-process AbundanceDip
problem! 128Te
130Xe

3rd Peak
195Pt

Rare earthelem.
232Th

238U

235U

80

100

120

140

Assumption: (n, γ)  (γ, n) equilibrium.

160

180200Mass A

220240Universality of r-process elements (Z > 56)

Decay Spectroscopy around mass A =160 was performed !

Rare-Earth Peak Formation at Freeze-Out Time
R. Surman et al. PRL 79 (1997)Test r-Process calculation with new RIBF data

92 β-Decay Half-lives (Mass A = 144 – 175)
vs FRDM+QRPA
J. Wu, PRL (2017)
CesiumLanthanum

Praseodymium

Promethium

Sudden reductionof T1/2 at N=96" 97
Barium

CeriumNeodymium

Europium

Terbium

Holmium

N=104 " 105Samarium

Gadolinium

Dysprosium

Nucleon paring effect92 β-Decay Half-lives (Mass A = 144 – 175)vs KTUY+GT2
J. Wu, PRL (2017)
CesiumBariumLanthanum

Praseodymium

Promethium

Europium

Terbium

CeriumNeodymiumSamarium

Gadolinium

Dysprosium

Holmium

KTUY+GT2 shows systematic trends similar with exp. values in mid-shell.
However, it can not reproduce even-odd effects.

92 β-Decay Half-lives (Mass A = 144 – 175)
vs RHB+pn-RQRPA
J. Wu, PRL (2017)
CesiumBariumLanthanum

Praseodymium

Promethium

Europium

Terbium

CeriumNeodymiumSamarium

Gadolinium

Dysprosium

RHB+pn-RQRPA underestimates the T1/2 for Z=55-56 (Cs, Ba) andoverestimates the T1/2 for Z =63-67 (Eu, Gd, Tb, Dy, Ho).
No reproduce of even-odd effects.

Holmiumr-Process Elemental Abundance (A = 150-179)

J. Wu et al. PRL (2017)

Uncertainty of β-decay half-lives " r-Process Rare-Earth Peak

Mass Model:
KTUY (Koura)

Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation

Rare-Earth Peak with Different Mass Models J. Wu

Mass & beta-decay half-lives


M.R.Mumpower, R. Surman et al.
arXiv:1609.09858



KTUY-GT2
RHB+pn-RQRPA
FRDM-QRPA Large
Uncertainty

Half-life (ms)  [MeV] 

J. Wu: PRL (2017)     Half-lives and Mass Measurement
mass (known)

Half-lives
Heavier region (Z>50)

EURICA Exp.
(2014)
H.Watanabe

EURICA Exp. (2013)
E. Ideguchi

EURICA Exp. (2013)
A.Odahara/C.B.Moon/R.Lozeva

From Now:
beta-delayed neutron
emission probabilities Pn
BRIKEN (2017 ~ )BRIKEN Setup

beta counting system: AIDA!
!" WAS3ABi "3He neutron detectors%BRIKEN# $ "γ-ray:
Two clover Ge detectors#(sec)

N=82

N=50

NNDC:
Total Pn …. ~ 150 nuclei + ...
Total P2n … 13 (mainly light RI)

BRIKEN: !-delayed neutron emissionsPn values:
How Sensitive in
r-Process Calc.?

low entropy hot wind

N=82high entropy hot windbeta-delayed neutron emitterscold wind

NS merger

M.R. Mumpower et al.
Prog. in Part. and Nucl. Phys
86 (2016) 86-126

r-Process Elements : Freeze-out Time

134In

134In

EURICA Collaboration$ countries%!"# collaborators

Acknowledgement:
Euroball Owners Committee
PreSPEC, GSI, IBS-RISP

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,EURICA
(2016
Sep.)
K. Moschner, D. Mucher, E. Nacher, J. Nagumo,
H. Naidja,WST. 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

Acknowledgement: Gammapool, Preepc, IBSBRIKEN Collaboration

Summary & Future
Z (number of protons)

half-lifesecin coming 3 years :beta-decay half-lives from EURICA/BRIKEN
beta-delayed neutrons from BRIKEN (EURICA)!" Mass (Q!)

82
50

50

28

28

Future ( ~ 3 years or later)
Decay spectroscopy in heavier region
Mass measurement at BigRIPS/ZDS
N (number of neutrons)