Decay spectroscopy at RIBF: The EURICA project and its impact on - - PowerPoint PPT Presentation
Decay spectroscopy at RIBF: The EURICA project and its impact on nuclear structure and astrophysics ISOLDE Workshop and Users meeting 2015 2 nd 4 th , December, 2015 Department of Physics and Astronomy, KU Leuven RI Physics Lab., RIKEN
ISOLDE Workshop and Users meeting 2015 2nd – 4th, December, 2015 Department of Physics and Astronomy, KU Leuven RI Physics Lab., RIKEN Nishina Center Zhengyu Xu for the EURICA Collaboration
High efficiency gamma-ray detector array + Highly segmented Si stopper / passive stopper + High beam intensity at RIBF (10 pnA 238U or 30 pnA 124Xe)
Isomer and b-decay spectroscopy!
Beta-decay half lives, Beta- delayed neutron-emission probabilities of exotic nuclei.
Maandag - vrijdag: 10u00 - 12u30 en 13u30 - 17u00 Weekdagen na 17u00 op afspraak Zaterdag op afspraak
Production Target
Separation
Identification
R R I I B B e e a a m m
EURICA 238U (124Xe) Beam RI Beam
Cluster Ge-detectors (gamma-ray detection) Cluster Ge-detectors (gamma-ray detection)
Beta-counting system inside EURICA
WAS3ABi ： beta-ray detection WAS3ABi ： beta-ray detection gamma-ray
Collaboration RIKEN / TUM / IBS
Production Target
Separation
Identification
EURICA
Passive stopper LaBr3(Ce) (fast timing)
Different stopper/detectors can be employed to meet the requirements of specific experiments.
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,
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,
Guadilla, T. Hashimoto, S. Hayakawa, J. Henderson, C. Hinke, N. Hinohara, E. Ideguchi,
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.-
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,
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,
Zhang
19 countries ： 238 collaborators ！
2012
124Xe
2013
238U
2012
238U
Half-lives (T1/2) Isomer (T1/2) Beta-delayed gamma Beta-delayed n, p EC, Qb, New isotopes K.Möschner T.Sumikama F.Browne I.Nishizuka P.-A.Söderström A.Jungclaus G.Simpson G.Lorusso Y.Shimizu A.Yagi E.Ideguchi, M.Tanaka R.Yokoyama W.Jin L.Sinclair Z.Y.Xu D.Lubos H.S.Jung M.Lewitwicz H.Suzuki G.Lorusso M.Niikura E.Sahin R.Lozeva Z.Li Orsay Gr. V.Warner Z.Patel F.Bello D.Sohler, Z.Vajta J.Park I.Celikovic G.Zhang H.Watanabe P.A.Söderström P.A.Söderström G.Benzoni A.Odahara P.Boutachkov H.Watanabe F.Naqvi S.Nishimura R.Gernhäuser G.Simpson G.Gey P.Davies T.Sumikama J.Wu P.S.Lee, C.B.Moon G.Lorusso J.Jin B.Blank B.Rubio, T.Fujita, .. A.Algora, . .
Shorter T1/2 beyond 78Ni: Pronounced in Z = 28, N=50 78Ni is a double magic nucleus !? Shorter T1/2 beyond 78Ni: Pronounced in Z = 28, N=50 78Ni is a double magic nucleus !? Decay curve of 79Ni
Z.Y.Xu, S.Nishimura, G.Lorusso et al., PRL 113, 032505 (2014)
77Co 78Ni 79Ni
It is found that the experimental R4/2 ratio is properly reproduced for A>36 by the shell model
for Cr isotopes, in terms of the interplay between the quadrupole correlations of the ν1d5/2 and ν0g9/2 orbitals and the monopole component of the π0f7/2 - ν0f5/2 interaction, thus driving the deformation in the neutron-rich Cr-Fe region. G.Benzoni et al., PLB 751, 107 (2015)
68Fe 69Fe 70Fe
From 400 ions of 70Mn
Delayed coin. with 128Pd ions (Δt=0.15-25 μs) γ-γ coincidence with a gate on 1311 keV
B(E2;8+→6+) B(E2;8+→6+) Good ν=2 in the well isolated πg9/2 subshell Good ν=2 in the well isolated πg9/2 subshell Robust shell closure at N=82 Robust shell closure at N=82 Seniority (ν) scheme Seniority (ν) scheme
128Pd82 130Cd82
A.Jungclaus et al., PRL 99, 132501 (2007)
2 2
2 1 2 2 1 2 ) 2 ; 2 (
eff
e j n j J J E B
2 Jπ=6+ seniority isomers in 136, 138Sn
20 40 60 80 Counts
a)
216 391 688
100 200 300 400 500 600 700 800 900 Energy (keV) 2 4 6 8 10 12 14 16 Counts
b)
168 461 715 50 100 150 200 250 Time (ns) 20 40 C per 12.4 ns T1/2=46(7) ns 250 500 750 1000 Time (ns) 10 20 C per 100 ns T1/2=210(45) ns
136Sn 138Sn
875,000 ions 5,000 ions ~640 ns flight time BigRIPS T1/2=46(7) ns
T1/2=210(45) ns
The excited states up to 6+
via the isomeric decay
the excitation energies of the first 2+ states was extended to 138Sn.
The life time of the 136Sn isomer is very short!!
The experimental B(E2; 6+ → 4+) rate of 136Sn can be reproduced by reducing the neutron pairing strength by ~150 keV, with the result that the first 4+ state now has mixed seniority (46% ν = 2, 55% ν=4). G. S. Simpson et al., PRL 113, 132502 (2014)
136Sn 138Sn 134Sn
N=50 N=82
20 40 60 Counts/2 keV 1000 2000 3000 4000 5000 6000 Energy (keV) 200 400 600 Counts/2 keV
988 keV
# # & @
132Cd 131Cd
x4
pg9/2
pp1/2
pp3/2
New pp3/2 single-hole energy in 132Sn !
empirical SM A.F. Lisetskiy realistic SM
No proton subshell structure !
PRL 112, 132501 (2014)
Two EURICA data sets: G.Simpson/A.Jungclaus & H.Watanabe/G.Lorusso
New Isotopes
144Te 140Sb 139,140Sn 136,137In 134,135Cd 131,132Ag 129,130Pd 127Rh 120,121Tc 118Mo
and more..
U-beam: 8 – 10 pnA ~ Two weeks Known T1/2
Two EURICA data sets: G.Simpson/A.Jungclaus & H.Watanabe/G.Lorusso
New Isotopes
144Te 140Sb 139,140Sn 136,137In 134,135Cd 131,132Ag 129,130Pd 127Rh 120,121Tc 118Mo
and more..
U-beam: 8 – 10 pnA ~ Two weeks Known T1/2
G.Lorusso et al., PRL 114, 192501 (2015)
80 100 120 140 160 180 200 220 240 Mass number A Solar-system abundance pattern
Before After new RIBF data
Dip problem!
Rare earth elem.
1st Peak 2nd Peak 3rd Peak
238U 195Pt 130Xe 232Th 235U 128Te
The new data with an (n, γ) (γ, n) equilibrium. ⇄ The new data with an (n, γ) (γ, n) equilibrium. ⇄
G.Lorusso et al., PRL 114, 192501 (2015)
104Zr is the most deformed of the neutron-rich Zr isotopes. In addition,
comparison of the magnitude of the extracted deformation with the results of model calculations indicate that these nuclei are prolate
Time-energy matrix from LaBr3.
104Zr 106Zr
164Sm and 166Gd
166Gd 166Gd 164Sm 164Sm
6- isomers have the
heavier N=102 isotones 170Er and
172Yb
nuclei to date
N=100
deformed magic number N=100
show that a deformed shell closure would have an effect on the masses
predict a deformed shell gap at N=100 from S2n
process abundance calculations
NPA722, C24 (2003)
The new half-lives have great impact on both nuclear structure and nuclear astrophysics.
study nuclear shell/shape evolution in neutron-rich nuclei with N=40, 60, 82, and 100.
neutron-rich nuclei around 78Ni and 132Sn.
126Pd80 126Ag79
PRL 113, 042502 (2014)
7- : ν(h11/2
10+ : ν(h11/2)-2
Long-lived isomer Ex = 2406 keV T1/2 = 23. 3.0(8) ms Jπ = (10+) Rint = 26(8) % B(E3) = 0.07(2) W.u.
Gated on conversion electrons Gated on compton electrons
0.4 0.8 1.2 1.6 2 Ex (MeV)
1181 406 1587 353
E3 M1
(11/2-) (13/2-) (15/2-) (21/2+)
exp SM
nh11/2 x 2+(130Cd) nh11/2 x 5-(130Cd) 5-: g9/2
2+: g9/2
=
E3
B(E3) is very sensitive to position of the pp3/2 and pf5/2 orbitals relative to the pg9/2 Position of pp3/2 orbital already fixed by the 988 keV g transition observed in 131In
Information on the missing fourth proton single-hole energy with respect to 132Sn ! T1/2 = 3.53(16) ms
Bexp(E3) = 505(23) e2fm6 = 0.51(2) W.u. BSM(E3) = 0.48 W.u. - for E(p3/2)-E(f5/2)=1.1 MeV and 0.5e
10 ms after 129Cd implantation Spectrum from Si
Spectrum from Ge Spectrum from Ge
PLB 738, 223 (2014)