Nuclear Physics

Hiroyoshi Sakurai

Element 113th

日研究人员称第三次合成１１３号元素

新华网东京９月２７日电（记者蓝建中）日本研究人员２７日称，他们第三次成功合成了１１３号元素。日本研究人员曾两次报告合成这一新元素，但均未被相关国际专门机构承认。

日本理化学研究所研究人员在新一期《日本物理学会志》网络版上报告说，

他们从２００３年开始，在加速器中使３０号元素锌和８３号元素铋融合，开始进行合成新元素的实验，２００４年和２００５年都曾成功合成１１３号元素。１１３号元素合成后平均２毫秒（１毫秒是千分之一秒）就开始衰变。此次合成的元素与过去两次合成的元素相比，衰变次数更多，而且能够在理论上预测其衰变是以一定概率发生，这进一步证实了新元素的存在。

日本理化学研究所此前曾两次宣称合成了１１３号元素，但是国际纯粹与应用化学联合会和国际纯粹与应用物理联合会认为“数据过少”，不予承认。俄罗斯和美国研究人员也曾于２００４年宣布合成１１３号元素。

迄今为止，排在元素周期表第１０５号元素之后的超重元素，在自然界中都很难出现。科学家们发现的一系列超重元素都是在实验室中合成的，它们往往在生成后极短时间内就衰变成原子量较小的其他元素。

2012

마침내발견된 113번원소AsiaNet 50767

(도쿄 9월 27일 AsiaNet=연합뉴스) RIKEN Nishina Center for Accelerator-based Science (RNC) 연구원들이그토록확보하기힘들었던 113번원자에대한가장확실한데이터를확보했다. RIKEN Radioisotope Beam Factory (RIBF)

실험에서 6회연속알파붕괴를실시한결과, 유명한딸핵종과의연계를통해 113번원소를확실하게밝혀냈다. 이획기적인결과로일본은 113번원소의이름을지을수있는권리를확보하게됐다.

자연발생하지않기때문에반드시실험을통해만들어야하는초중원소를찾는것은매우힘든과정이다. 1940년첫번째초중원소가발견된후여러나라에서초중원소를합성하고자경쟁해왔다. 미국이 93~103번원소를발견했고, 러시아와미국이 104~106번원소를발견했으며, 독일이 107~112번원소를발견하고, 러시아와미국이공동으로 114번과 116번원소를발견했다.

Kosuke Morita 연구원과그가이끄는 RNC팀덕분에, 일본은아시아최초로원자이름을명명하는국가가될전망이다.

그는맞춤기체충전반동이온분리기(gas-filled recoil ion separator, GARIS)와반응생성물을파악하기위한위치민감성반도체검출기를이용하여수년동안 113번원소를찾고자노력했다. 8월 12일, 드디어그의실험이결실을봤다. 아연이온이가는비스무트층과충돌하여아주무거운이온과 113번원소동위원소생성물로파악된 6회연속알파붕괴가발생시킨것이다.

Morita 팀은 2004년과 2005년실험에서도 113번원소를검출했는데, 초기결과에서는고작 4회붕괴와두브늄-262(105

원소) 자발핵분열밖에알아내지못했다. 동위원소두브늄-262는알파붕괴를통해붕괴하는것으로알려져있는데, 이를관찰한이는없었다. 또한당시최종산물이유명한핵종이아닌관계로명명권리도부여되지않았다. 이번에밝혀진연쇄반응에서는대안적인알파경로를취한다. 데이터결과두브늄은로렌슘으로붕괴되고최종적으로멘델레븀으로붕괴되는것으로나타났다. 두브늄-262가로렌슘-258로붕괴되는것은잘알려져있으며, 113번원소가연쇄반응의기원이라는확실한증거를제시한다.

Morita 팀의획기적인이번발견은초기결과와더불어 113번원소명명권리를주장할수있는근거를제시한다. Morita는“우리는 9년동안확실하게 113번원소를밝혀낼수있는데이터를찾았다”면서 “마침내그데이터를찾았고, 이제어깨에서무거운짐을내려놓은기분이다. 113번이우리것이될거라믿고열심히일해준모든연구원과스태프들에게감사를드린다. 이후에는 119번이후원소들을찾을계획”이라고말했다.

참조:

2012

Find anything about “113” !

Prime number ; 29th 109, 30th 113, 31st 127

Telephone number ; 113 in case of phone trouble (only in Japan)

Postal Code ; 113-XXXX Bunkyo-ku, Tokyo

Dates ; Jan. 13th, Nov. 3rd, 11th March (it depends on dating)

Flight number ; NH-113, NH-278

Gate number ; 113th Gate in Haneda Airport

National highway number; between Niigata-city and Souma-city (Fukushima)

Marinated boiled-egg; golden-ratio of seasoning soy-sauce 1 : “sake” 1 : water 3

…..

Fundamental interactions

Elementary particles

Composite particles

Nuclear Physics is not Particle Physics,

not Condensed Matter Physics

Interaction?

Effective interaction ?

Correlations ?

Isospin, Density, temperature dependences ?

Surface boundary, non-linear, finite system

Collective motions

Q. 1 Life time of neutron？

Q. 2 Age of universe is 13.7B Years after BigBang.

At present, there are neutrons in materials. Why?

Q. 3 Spin-parity for ground state of deuteron？

Q. 4 Limits of existence of nuclei？

Q. 5 Magic numbers of nuclei？

Q. 6 Size of nuclei？

Q. 7 Collective motions of nuclei？

Q. 8 How and where elements around us have been created ?

Exploration of the Limit of Existence

82

8

20

28

50

8

2028

50

82

126

1985年の核図表

proton-rich nuclei

neutron-rich nuclei

stable nuclei ~300 nuclei

unstable nuclei observed so far ~2700 nuclei

drip-lines (limit of existence)（theoretical predictions) ~6000 nuclei

magic numbers

proton drip-line

neutron drip-line

neutron number (N)

proton number (Z)

in 1985

“Magic Numbers” in Nuclei

Magic numbers = 2, 8, 20, 28, 50, 82, 126,…

Shell Structure

One-body potential

Large LS term

(surface contribution)

Magic numbers ->

2, 8, 20, 28, 50 …

Nobel Prize 1963

Mayer & Jensen

28

2028

50

82

126

Reiner K.

Nuclear Phys. 67 (1965)1

Nuclear Collective Motion

0+

2+

4+

6+

0+

2+

4+

6+

0+ 2+

4+0+ 2+ 3+

0+

2+

4+

6+

E(4+)/E(2+) ~ 1.8 ~ 2.2 ~ 3.3

deformed nucleisurface vibrationspherical nuclei

closed shell open shell

Quadrupole

deformation parameter b|b|~0 |b| large

degree of collectivity

at magic number

E(2+)

Magicity through determining E(2+)

828

20

28

50

82

82

50

126

[keV]

Z

N

2002

Collective motions

Surface Violation, Deformation:

Spontaneous Symmetry Breaking

Self-Condensation

alpha-decay, fission-decay

Molecular structure （8Be = α+α, 3α in 12C）

Shell Structure

LS term (surface contribution)

Magic numbers 2, 8, 20, 28．．．

Density SaturationSize of nuclei = 1.2 x A1/3 fm

1s1/2

1p3/2

1p1/2

1d5/22s1/21d3/2

1f7/2

2p3/21f5/22p1/21g9/2

2

8

20

28

50

82

1g7/22d5/22d3/23s1/21h11/2

BCS paring of nucleonsSuper-fluidity in moment of inertia

Atomic Nuclei

Nuclei : Many-body quantum-system

with spontaneous order and self organization

To establish a unified picture for atomic nuclei

Q. 1 Life time of neutron？

Q. 2 Age of universe is 13.7B Years after BigBang.

At present, there are neutrons in materials. Why?

Q. 3 Spin-parity for ground state of deuteron？

Q. 4 Limits of existence of nuclei？

Q. 5 Magic numbers of nuclei？

Q. 6 Size of nuclei？

Q. 7 Collective motions of nuclei？

Q. 8 How and where elements around us have been created ?

Solar Abundance of Elements

Big Bang

Nucleosynthesis in stellars (fusion）

金

Nucleosynthesis in r-process path

T.Motobayashi

陽子数

中性子数

Beta decay

Z, N -> Z+1, N-1

r-process

r-process path in supernova explosion

Photo-disintegration of ion nuclei

Electron capture reaction

Emission of big amount of

neutron and neutrino

Neutron capture

Beta decay

Fe to U

Au

Pro

ton n

um

ber

Neutron number

Exploration of the Limit of

Existence

82

8

20

28

50

8

2028

50

82

126

1985年の核図表

proton-rich nuclei

neutron-rich nuclei

stable nuclei ~300 nuclei

unstable nuclei observed so far ~2700 nuclei

drip-lines (limit of existence)（theoretical predictions) ~6000 nuclei

magic numbers

proton drip-line

neutron drip-line

neutron number (N)

proton number (Z)

in 1985

New frameworks for the new region of nuclear chart

neutron-halo nuclei

neutron-skin nuclei

1s1/2

1p3/2

1p1/2

1d5/22s1/21d3/2

1f7/2

2p3/21f5/22p1/21g9/2

2

8

20

28

50

82

1g7/22d5/22d3/23s1/21h11/2

Stable Nuclei Neutron-rich Nuclei

N=16

?

?

11Be, 11Li, 19C...

?

To write up new text book： Exotic phenomena, Systematics, etc.

Isospin-, density-dependences of effective interactions, nucleon-corrections

Microscopic system (nuclei) to Macroscopic system (neutron stars)

Nuclear Matter: New formsNuclear Structure: Shell evolution

lost

lost new magicity

E(2+)

Magicity and its loss through determining E(2+)

828

20

28

50

82

82

50

126

[keV]

Z

N

2002

Shell Evolution : magicity loss and new magicity

Shape ?

Shell gap？Single particle level？Cluster formation?

Role of 3NF ?

Magicity loss ？50、82、126、184

Challenges in establishing new frame work of nuclear physics

Liberation from Stable Region and Exotic Nuclei

New quantum objects with two surfaces

Skin thickness？Density distribution？Role of skin in reactions？Pairing in skin？ di-neutrons?

Exotic modes of skin？

RIBF provides data for nuclei far from the stability line

Density distribution

陽子・中性子一様物質

r

Neutron+

proton

neutrons

Spherical Deformed

neutron skin

proton-

neutron

matter

Dynamics of new “material” : Neutron-skin（halo）

E(2+)

Synthesis up to U （r-process）unknown neutron-rich nuclei

theoretical predictions only

Necessary of experimental investigation

for nuclear properties of heavy and

neutron-rich nuclei

Mass, life-time, decay mode

Challenge for r-process path and explosion in supernovae

5

Explosion mechanism of supernovaNo explosion in theoretical works

Outer clast of neutron star

Necessary of experimental study for

Equation-of-State for nuclear matter

Mass number

1987A

Challenge to investigate EOS of neutron matter

r (fm-3)

Normal density

E/A

[M

eV

]

3NF

T=3/2 channels?

density dependence?

1S correlation

BCS-BEC crossover

in dilute system (r ~ 0.1r0) ?

3P2 correlation

pairing gap?

Density depencence?

from nuclei to neutron stars

B. A. Brown, PRL85 (2000) 5296

Role of di-neutron in skin? : collectivity, transfer reactions

Elastic d+p for T=1/2

Nuclear structure in

very neutron-rich nuclei for T=3/2?

Heavy-ion Collisions to achieve r~2-3r0 ?

????

pure neutron matter

A

RI Beam Factory

Gas-catcher

5 cyclotrons + 2 linacs

3 inflight separators

Experimental devices

coupled with BigRIPS

have been completed in FY13

SHE

113th

RI beam production via in-flight method

Heavy ion accelerator

（to collect and

separate RI with

analyzing magnets）

RI production

RI beam

target

（to accelerate nuclei）

RI beam separator

Yield rate of 78Ni via fission is

about 1､000 times higher than

via fragmentation.

78Ni

N=50

10,000:1

Fission reaction via 238U beam

Fragmentation reaction via 86Kr beam

Proton number

Pro

babili

ty

（to make reactions

Be, C, etc）

Advantage of fission via U beam

K980-MeVIntermediate stage Ring Cyclotron (IRC)

World’s First and Strongest

K2600MeV

Superconducting Ring Cyclotron

World’s Largest Acceptance

9 Tm

Superconducting RI beam Separator

400 MeV/u Light-ion beam

345 MeV/u Uranium beam

SRC

BigRIPS

~250-300 MeV/nucleon RIB

82

50

60

70

10090

124Xe

70Zn

18O

Z

N

50

28

20

2820

8

8

238U In-flight fission

124Xe

48Ca

78Kr

145 new isotopes

Production Yield Measured (1344)

New isotope 2011

RI beam Produced (386) for 103 Experiments

New isotope 2014

New isotope 2007, 2008

New isotope 2015

New isotope 2012 New isotope 2013

0.01

0.1

1

10

06 07 08 09 10 11 12 13 14 15

100

1000

pol-d

d

4He 14N

18O48Ca

70Zn 78Kr

124Xe

238U

year

pnA x1000

Primary beam intensity

RI Beam Production at BigRIPS Since 2007

32Ne:: Doornenbal, PRL 103, 032501 (2009) 31,32,33Na: Doornenbal, PRC 81, 041305R (2010)33,34,35Na: Doornenbal, PTEP 2014, 053D01 (2014)32Mg: Li, PRC 92, 014608 (2015)36,38Mg: Doornenbal, PRL111, 212502 (2013)42Si : Takeuchi PRL109, 182501 (2012)40Mg : Crawford PRC 89, 041303 (2014)54Ca: Steppenbeck , Nature 502, 207 (2013)50Ar : Steppenbeck, PRL 114, 252501 (2015)66Cr, 72Fe : Santamaria, PRL 115:192501 (2015)126Pd: Wang, PRC 88 054318 (2013)136Sn: Wang, PTEP 023D02 (2014)

106,108Zr:: Sumikama, PRL 106, 202501 (2011)126,128Pd : Watanabe, PRL 111, 152501 (2013) 78Ni: Xu, PRL 113, 032505 (2014) 136,138Sn : Simpson, PRL113, 132502 (2014)

©仁科記念財団

Shell Evolution

New Magicity of N=34

Magicity Loss at N=20、28

New magic number N=34

Double magicity of 78Ni（Z=28, N=50）Magicity at N=82 with Z>46…

“Asahi Shinbun” News Paper, 18th Aug., 2014

RI Beam Factory

Magic Numbers of Elements

r-process path

rapid neutron-capture

vs beta-decay

Mass -> path location

Half-life -> matter flowIsotopes found

at RIBF

N=50

N=82

N=126

The r-process

nucleosynthesis

known

William A. Fowler1983 Nobel Prize Physics

© The Nobel Foundation

1st peak

2nd peak

3rd peak

Supernova explosion?

NS merger?

Or both?

“Revolution” in the r-process research

G. Lorusso, S. Nishimura et al. PRL. 114, 192501 (2015)

w/o new data

w/ new data

Bunch of T1/2 data for A~100

A standard model assuming (n,gamma)

equilibrium reproduces the r-abundance

up to rare-earth region

Mass, beta-delayed neutron emission probability

measurement in future

S. Nishimura et al., PRL. 106, 052502 (2011)

Z. Y. Xu, S. Nishimura et al.: PRL. 113, 032505 (2014)

G. Lorusso, S. Nishimura et al.: PRL. 114, 192501 (2015)

G. Benzoni, A.I. Morales, H. Watanabe et al.: PRC 92, 044320 (2015)

P. Lee, C.-B. Moon, C. S. Lee, A. Odahara et al.: PLB 751, 107 (2015)

Next step should be for the 3rd peak

mass

half-life

excited states

deformation

charge radii

matter radii

charge distribution

matter distribution

EM moments

single particle states

astrophysical reactions

giant resonances

exotic modes

HI collisions (EOS)

IRC-to-RIPS BTSLOWRI

SHARAQ spectrometer

SAMURAI SCRIT

Rare RI ring

U Tokyo

New Devices of RIBF

for several 100 – 1000 species

2008-

2009-2011- 2010-

ZeroDegree

To maximize the potentials of intense RI beams available at RIBF

Ye et al., July 2009

Recoiled proton tagged knockout reaction for He-8 at RIPS

PKU-RIKEN-IMP-TITech-Seaul

“Quasi-elastic scattering of He-6 from C-12”

Lou and Ye et al., PRC 83, 034612 (2011)

“Recoil proton tagged knockout reaction for He-8”

Cao and Ye et al., PLB 707, 46-51 (2012)

Challenge

Action

Discussion

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