Ю.Ц.Оганесян Лаборатория ядерных реакций им. Г.Н. Флерова

Ю.Ц.Оганесян

Лаборатория ядерных реакций им. Г.Н. ФлероваОбъединенный институт ядерных исследований

Пределы масс и острова стабильности сверхтяжелых ядер

Физика фундаментальных взаимодействий 2009

Сессия-конференция секции ядерной физики ОФН РАН 23-27 ноября, 2009г., ИТЭФ, Москва

110

120

100

90

80

70170

neutron number

pro

ton

nu

mb

er

180 190110 120 130 140 150 160

92U / Tα = 4.5·109 y

Chart of nuclidesChart of nuclides

82Pb / stable

Bi

Th

102No / Tα ≈ 2 s

about 50 years ago…

Macroscopic theory (Liquid Drop Model)

Spontaneous fission

TSF = 2·10-7 y

TSF = 1016 y

TSF < 10-14 s

0.70 0.75 0.80 0.85Fissility param eter x Fissility param eter x

Fis

sio

n B

arri

er H

eig

ht

B

/ M

eVf

0.900.800.700.600

5

10

15

20

25

30

3035

LDM

neutron capture

20

10

0

-10

-20

Lo

gT

/ s

SF

0.90 0.95

Spontaneous FissionSpontaneous Fission Macroscopic theory (Liquid Drop Model)

238U 255Fm

208Pb

6.0 MeV SF-isom ers

fusion w ith heavy ions

Exp.

Ю.Ц. Оганесян «Пределы масс атомных ядер» 27 ноября 2009г. ИТЭФ, Москва

110

120

100

90

80

70170

neutron number

pro

ton

nu

mb

er

180 190110 120 130 140 150 160

Chart of nuclidesChart of nuclides

184

114

sphericalshells

152

100

deformedshells

162

108

deformedshells

sphericalshells

126

Pb

X

8282

Nuclear shells (macro-microscopic approach)

0 .900 .800 .70

E xp.

LDM

F iss ility P a ram ete r x

0

5

10

15

238U

255Fm

114 116

Fis

sion

Ba

rrie

r H

eig

ht

Bf /

Me

V

Fission Barriers

20

10

0

-10

-20

0 .70 0 .75 0 .80 0 .85 0 .90 0 .95

Lo

gT /

sS

FLDM

F iss ility P aram ete r x

114Z=112116

…and Half - Lives

R. Smolańczuk, Phys. Rev. C 56 (1997) 812

Predictions of the microscopic theoryPredictions of the microscopic theory

Island of Stability

shoal

peninsula

continent

New landsNew lands

Neutron number

Pro

ton

nu

mb

er

100 110 120 130 140 150 160 170 180 190

120

110

100

90

80

70

Island of Stability

Shoal

New landsNew lands Microscopic theory

Peninsula

Continent

Sea of Instability

about 40 years ago…

-5 0 5 10 15 LogT1/2 s

1µs 1s 1h 1y 1My

Reaction of Synthesis

108

162

114

90

142126 146 184

Th U NW N N E

SW

W

Pb

Pu

peninsula

continent

shoal of deform ed

nuclei

island of stability

of superheavy nuclei

neutron num ber

pro

ton

nu

mb

er

Reactions of synthesis

Light ions

Neutron capture

Cold fusion

target from

“continent”

Act.+48Ca

target from“peninsula”


-2-2

-3

-3

-6

-6

-5

-5

-7

-4

-4

-4

-14

120 130 160140 170150 180

80

90

100

110

120

190

SHE

Pbneutrons →

Cold fusionCold fusion

Act.+48CaAct.+48Ca

pro

ton

s

→

Reactions of SynthesisReactions of Synthesis

U

P b B i

T h

Neutron captureNeutron capture

Hotfusion

Hotfusion


No

Rf

22Ne26Mg34S (5n)

Db

Sg

Hs

Bh

Ds

1 0 -30

1 0-32

1 0-34

1 0-36

1 0-38

4n

-cro

ss s

ect

ion

(c

m)

2

Projectiles

48Ca

112

112

114

116

140 150

152 162

180160 190170Neutron number

184

σxn ~ (Γn / Γf)x;

х – number of evaporated neutrons

(Γn / Γf) ~ exp [(Bf – Bn)]

Bf = BfLD + ΔEShell

0

Cross sectionsCross sections

Ex=40-50 MeV

Yu. Oganessian et al. Phys. Rev.

90

100

110

120

1 2 3 4 5 6 7 8

120 130 140 150 160 170 180 190Neutron num ber N

Calculated Barriers Heights (M eV)

P. Moller et al., Phys. Rev., C79, 064304 (2009)

Bf (MeV)

Pro

ton

num

ber

Z

Act + 48Ca

208Pb

298114

spherical

deformed

deformed

spherical


Act. + 48Ca

Targets: thickness (mg/cm2)

Isotopeenrichment (%)

233U 0.44 99.97

238U 0.35 99.3

237Np 0.35 99.3

242Pu 0.40 99.98Chemistry 1.4 99.98

244Pu 0.38 98.6

243Am 0.36 99.9Chemistry 1.2 99.9

245Cm 0.35 98.7

248Cm 0.35 97.4

249Cf 0.34 97.3

Projectiles 48Ca

Energy: 235-250 MeV

Intensity: 1.0-1.2 pμA

Consumption: 0.5 mg/h

Beam dose: (0.3-3.0)∙1019

Reactions of SynthesisReactions of Synthesis

249Bk 0.35 ≥ 90

Dubna Gas Filled Recoil Separator

Measured parameters:

For recoils:

energy TOFpositions

For decayproduct:

energy timepositions

Experimental SetupExperimental Setup

position sensitivestrip detectors

“veto” detectors

TOF-detectors

SH-recoilside

detectors

Total detection efficiency: for α-particles…………..83% for SF-fragment…….~ 100% for both fragments……..42%


108

275

5.4s

9 30. M eV

8. 4 M eV 5

9.70 M eV

0.26 s 5

9.52 M eV

SF10%

4110

279

106

271

3

2

0.42 s

48 s

SF>90%

114287

10.01 M eV

0.54s

3n

112283

3n 238 48U + C a,

11 2

283

116291

3n 246 48C m + C a,

1242Pu +48Ca, 3n

104

267

228 M eV 381 s

S F

6

Yu. Oganessian J. Phys. G. 34 (2007) R165

strip number

posi

tion

252No

20

30

40

10

0-3 -2 -1 0 1 2 3

0.65 m m

Position deviation (mm)

Co

un

ts /

0.1

mm

Detector

area ~5000 mm2

Pixel: 6.5 mm2

279110

8.0 9.0 10.0 11.0 12.0

283112

283112

275108

9.0

E

10.0 11.0 12.0

287114

286114

Alpha particle energy (MeV)

242Pu(48Ca; 3n, 4n)287,286114

287114

283112

291116

286114

290116

245Cm(48Ca; 2n, 3n)291,290114

271106

238U(48Ca; 3n, 4n)283,282112

294118

249Cf(48Ca; 3n),294114

even-oddeven-even

Alpha-particle spectra of SH-nucleiAlpha-particle spectra of SH-nuclei

10

50

0.1

0.5 C

ross

se

ctio

ns

/ 3 M

eV (

rela

tive

units

)

1

5

3n2n

3n

2n

4n5n

4n

5n

30 3525Excitation energy (MeV)

40 45 50 55

xn-channel cross sectionsfrom 242,244Pu+48Ca reactions

the maximum cross sections for evaporation residues are observed at the excitation energy ~ 40 MeV (hot fusion).

Excitation functionsExcitation functions


249 48Cf + Ca2n 3n

1

2

3 ev. 11 ev. 116

290

10.15 M eV

206 MeV, 1.5+1.0

-0.4 m s

0.17 +0.09-0.04 s

9 . 7 m s+6.4-2.826 m s+32

-9

10.84 M eV 10.74 M eV

114

108

106

287

275

271

10.03 M eV

1.1 s+1.3-0.4

9.70 M eV

5

6

9.55 M eV

7.0 s+8.3-2.5

4110

279

112

104

283

267

245 48Cm + Ca

3

0.42 s

0.55 s+0.76-0.19

91 .1 s

240 MeV

21 m in SF

1116

291

8.84+_0.36

9.56 +_0.34 M eV

2

SF SF~50%

112282

114286

3n

3 ev.

116

118

290

294

10.16 M eV

202 M eV

0.22 +0.26-0.08 s

0.9 m s+ .-0.

1 03

14 m s+17- 5

1.3 m s+1.5-0.5

10.82 M eV

11.65 M eV

1

1

3

SF

112

282

286

114

Yu. Oganessian et al., Phys. Rev C 74, (2006) 044602

Synthesis of Element 118Synthesis of Element 118


244Pu, 248Cm

113/282

10.63

73 ms

111/2 87

10.69

4.2 ms

109/2 47

9.76

0.45 s

107/2 07

105/266

104/268

0.37 h

8.93

1 min

237Np

115/287

10.59

3 ms2

113/283

10.12

0. s1

111/279

10.37

0.17 s

109/2 57

10.33

9.7 ms

107/2 17

105/267

1.2 h

109/276

9.71

0.72 s

107/272

9.02

9.8 s

113/284

10.00

0.48 s

115/288

10.46

87 ms

105/268

1.2 d

111/280

9.75

3 6. s

104/268

243Am242Pu, 245Cm

249Cf

DecaychainsDecaychains

36 nuclides

89 decay chains

was registered

Db270

117 117

115115

113113

111111

109

107

294

290289

286285

282

278

274

281

293

249Bk(320d)+48Ca

FLNR-ORNL-LLNLcollaboration

22 mg of 249Bk have been produced at Oak Ridge National Laboratory by intense neutron irradiation for 250 days in the High Flux Isotope Reactor


June 2009

1

2 114288

9.94+_0.06 M eV

0.8 s+0.3-0.2

TKE 228 +_ 7 M eV

SF>90%

0.1 s+0.03-0.02

112

284

116

292

10.02 +_ 0.06 M eV2

0.5 s+0.2-0.1

9.54+_ 0.06 M eV

TKE 225 +_ 7 M eVSF>90%

3.8 s+1.2-0.7

0.2 s+0.05-0.04

110

279

112

283

3

1

114287

116

291Dubna 2002-2004DGFRS

ConfirmationConfirmation

16 evens 18 evens2 114

288

9.9+_ 0.1 M eV

SF0.1 s

112

28410.04 MeV

2

9.49+_ 0.12 M eV

TKE ~ 220

>3 s

0.21 s+0.3-0.1

110

279

112

283

3

114287

R. Eichler et al., Nature 447 (2007) 72

FLNR / PSI

5 events

3 events

Dubna 2006-2007

Reaction:

242,244Pu + 48Ca - 287,288114 + 3,4n

CHEMISTRY

9.52+_ 0.02 M eV

6.9 s+6.9-2.3

0.18 s+0.32-0.07

TKE 210 M eV+32-11

110

279

112

283

3

S. Hofmann et al., Eur. Phys. J. A32 (2007) 251

Darm stadt 2007GSI SHIP

Reaction:

U + Ca - 112 +3n238 48 283

4 events

22 events

Decay Properties

12.0

11 .0

10 .0

110

112

Z -even

T heory :

114

116

118

108

106

9.0

8.0

7.0260 270 280 2 09 300

A tom ic m ass num ber

Alp

ha d

eca

y en

erg

y (M

eV)

Z -even

E xp:

-6

-8

-4

-2

0

2

4

6

8

10

12

14

16

18

Z=112

112

114110

Rf

No

Cf

N=152

N 6=1 2

N 5=1 2N 84=1

Fm

140 145 150 155 160 165 170 175 180 185

N eu tron num ber

Log

T

(s)

SF

Exp.

Th.

H sD s112114

S gR fC f-N o

108

Spontaneous fission half-livesSpontaneous fission half-lives

Actinides

Trans-actinides Superheavy nuclei

155

Neutron num ber

Hal

f-lif

e,

T

(s)

160 165 170 175

118

116

114

112

112

113

113

112

112

110

110

111

111115

1801 0 -6

1 0 -4

1 0 -2

1 0 -4

1 0 0

1 0 2

sf

sf

sf

sf

Half lives of nuclei with Z ≥ 110

Half lives of nuclei with Z ≥ 110

Act. + 48Ca

N=162

available for chemical studies

With Z >40% larger than that of Bi, the heaviest stable element, that is an impressive extension in nuclear survival.

Although the SHN are at the limits of Coulomb stability, shell stabilization lowers: the ground-state energy, creates a fission barrier, and thereby enables the SHN to exist.

The fundamentals of the modern theory concerning the mass limits of nuclear matter have obtained experimental verification


neutrons →

pro

ton

s

→

-2-2

-3

-3

-6

-5

-5

-7

-4

-4

-4

-14

120 130 160140 170150 180

80

90

100

110

120

190

SHE

U

P b B i

T h

Search for SHE in Nature

Atomic structure and chemical properties

of the SHENuclear structure

and decay propertiesof the SHN

Search fornew shells


Chemical properties

7s

6s

5s

5d

4d4s3s2s

5fr max

rel /r

max

non-

rel

4f

Relativistic Contraction

non-

relativistic

7s

6s

5s

5d

4d4s3s2s

5f

4f

0,80

0,75

0,85

0,90

0,95

1,00

1,05

7s

6s

5s

6p5p4p

5d

4d

3p

4s3s2s

5f

0 20 40 60 80 100 120Z

1s 2p3d

4f

rm ax : principal maximum of the wave function of the outermost orbital

J.P. Desclaux, At. Data Nucl. Data Tables 12 , 311 (1973)J.P. Desclaux, At. Data . Data Tables 12 , 311 (1973)J.P. Desclaux, At. Data . Data Tables 12 , 311 (1973)

-

relativistic

SHE

112114

Atomic propertiesAtomic properties

HgPb

~ Z2


H

1

Li

3

Be

4

Na

11

M g

12

K

19

Ca

20

Sc

21

104

Ti

22

V

23

Cr

24

M n

25

Fe

26

Co

27

Ni

28

Cu

29

Zn

30

1

2

3 4 6 7 8 9 10 11 12

13 14 15 16 17

18

1

2

3

4

5

6

He

B

Al Si P S

ONC F

Cl Ar

Ne

7105 106 107 108 109 110 111 112 113 115114 116 117 118

72 74 75 76 77 78 79 80 81 82 83 84 85 8655 56

87 88

37 38 39 40 42 43 44 45 46 47 48 49 50 51 52 53 54

31 32 33 34 35 36

Rf Db Sg Bh Hs M t

Rb Sr Y Zr M oNb Tc Ru Rh Pd Ag Cd In Sn Sb Tc I Xe

Cs Ba Hf WTa Re O s Ir Pt Au Hg Ti Pb Bi Po At Rn

Fr Ra

G a G e As Se Br Kr

Da

rms-

tad

tiu

mDs Rg

ChemicalpropertiesChemicalproperties

82

Pb

50

Sn

14

1121 10

Ds

Ch

emic

al is

ola

tio

n

80

Hg

4 8

C d

12

114

Ca

20

Pu

94

86

Rn

relativisticrelativistic

Reaction:

242Pu(48Ca,3n)287114[0.5s]→α→283112[3.6s]

Compound Hg(Au)

and 112(Au)

Compound Hg(Au)

and 112(Au)

R. Eichler et al., Nature 447 (2007) 72

Au

SiO2


4 81

50

50

-50

-50

0

0

-100

-100

-150

-150

-200

-20012

Rn

RnHg

Hg

RnHg

Detector num ber

Tem

per

atu

re

C 0

Tem

pe

ratu

re

C 0

16 20 24 28 32

4 81 12Detector num ber16 20 24 28 32

0

10

20

30

40

50

Re

lati

ve

yie

ld %

0

10

20

30

40

50

Rel

ati

ve

yie

ld %

Gold Ice

Gold Ice

4 81

50

-50

0

-100

-150

-20012

RnHg

Detector num ber

Tem

per

atu

re

C 0

16 20 24 28 320

10

20

30

40

50

Rel

ati

ve y

ield

% Ice

He/Ar + + Hg Rngas flow 0.86 l/m in

gas flow 0.89 l/m in

gas flow 1.5 l/min

on ice!

on goldon gold

on goldon gold

on goldon goldon goldon gold

112

112

112

Element 112 is a noble metal – like Hg

room temperature

Reaction:

242Pu(48Ca,3n)287114[0.5s]

Compound Pb(Au) and 114(Au)

Compound

1

2

114

112

287

283 10.02 MeV 0.5 s

9.54 MeV 3.8 s

0.2 s TKE=225MeVSF

110281

1

2

114

112

287

283 10.04 MeV

9.53 MeV 10.9 s

0.24 s TKE= 220MeVSF

110281


more and more inert?

H

1

Li

3

Be

4

Na

11

M g

12

K

19

Ca

20

Sc

21

104

Ti

22

V

23

Cr

24

M n

25

Fe

26

Co

27

Ni

28

Cu

29

Zn

30

1

2

3 4 6 7 8 9 10 11 12

13 14 15 16 17

18

1

2

3

4

5

6

He

B

Al Si P S

ONC F

Cl Ar

Ne

7105 106 107 108 109 110 111 112 113 115114 116 117 118

72 74 75 76 77 78 79 80 81 82 83 84 85 8655 56

87 88

37 38 39 40 42 43 44 45 46 47 48 49 50 51 52 53 54

31 32 33 34 35 36

Rf Db Sg Bh Hs M t

Rb Sr Y Zr M oNb Tc Ru Rh Pd Ag Cd In Sn Sb Tc I Xe

Cs Ba Hf WTa Re O s Ir Pt Au Hg Ti Pb Bi Po At Rn

Fr Ra

G a G e As Se Br Kr

Dar

ms-

tad

tiu

m

Ds Rg

5

73

41

?

Periodic Table of ElementsPeriodic Table of Elements

114 115

Yu.Oganessian. Perspectives of JINR – ORNL Collaboration in the studies of SHE. JINR Scientific Council, Sept 24-25. 2009, Dubna

184

evidence of enhancedstability of SH nucleievidence of enhancedstability of SH nuclei

152

162

neutron shellsof SH-nucleineutron shellsof SH-nuclei

82

10 5

126

coldfusion

coldfusion

hotfusionhotfusionhotfusionhotfusion

chemistry ofTA-elementschemistry ofTA-elements

SF-isomersSF-isomers

fissionmodesfissionmodes

“relativistic effect” in SH - atoms“relativistic effect” in SH - atoms

search for SHEin Nature

search for SHEin Nature

Progress in HE-researchProgress in HE-research

neutrons

prot

ons

Спасибо за внимание к моему сообщению

Log

T (

sec.

)α

150 160 170 180 190140

5

15

10

20

0

-5

-10 116

118

112

114

110

108

108

N eutron num ber

α - decay

Deform edShell

SphericalShell

A g e o f th e E a rthsearch

in na turesearch in thecosm ic rays

108 y

105 y

1 y

1 d β -s tab lenucle i

Search for SHEIn NatureSearch for SHEIn Nature

50

60

70

80

90

100

110

120

120100 1 04

neutron drip line

proton drip line

1 06

neutron num ber

pro

ton

nu

mb

er

1 08 200

126

A =195

105

82

50

ThU

Pu

Pb

Hs

184

A =278

waitingpoint

β-β-

β-

waitingpoint

90

140 160 180 200 220

100

110

Z

N

120 B < 2.5 MeVf

B > 6.5 MeVf

2.5 M eV < B < 4.5 M eVf4.5 M eV < B < 6.5 M eVf

4 3

3

2

2

1

1

A. Mamdouh et al.,Nucl. Phys. A679 (2001) 337

Extended Thomas-Fermi plus Strutinsky integral method

Calculated fission barrier heightsCalculated fission barrier heights

-2 -3

-4

-4α-decay

β--decayEC

SF

Z=108

Cyclamen1966

5 .0

4 .0

3 .0

2 .0

230220 240 250

268 Db

260 270 280 290 300

U

Pu

Cm

Bk

M ass num ber A

Ave

rage

nu

mb

er

of

neu

tro

ns p

er f

issi

on

Cf Fm

symm .fission

asymm .fission

No

1 .0

6 .0

E xp.7 .0

286 Hs282 Sg symm .

fission

asymm .fissionC a lc.

the counting rate 1 decay / year from a 1000-g metallic Os samplecorresponds to the ratio Hs/Os:

~ 7·10-16 g/g

or ~ 10-23 g/g

in the Earth's crustor in the meteorit’smatter

Assuming for the SH-nuclide TSF = 109 years

Fréjus peakFréjus peak

ModaneModane

Os-sample550 g. (metallic)

3He - counters

in comparison with previous attempts

the sensitivity is increased by a factor ~ 109

Yu. Oganessian “Heaviest Nuclei” Int. Conf. Nuclear Structure & Dynamics. May 4-8, 2009, Dubrovnik, Croatia

150 160 170 180 190

Z = 108

140N eu tron num ber

LogT

(ye

ars

)1

/2

-15

10

-5

-10

5

0

Age of the Earth4.56 .10 y9

SFSF

search in nature

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Ю.Ц.Оганесян Лаборатория ядерных реакций им. Г.Н. Флерова