Reactions of Synthesis and Decay Properties of Superheavy Elements Yuri Oganessian Flerov Laboratory...

Reactions of Synthesis and Decay Properties of Superheavy Elements

Yuri Oganessian

Flerov Laboratory of Nuclear ReactionsJoint Institute for Nuclear Research

141980 Dubna, Moscow region, Russia

HEAVIEST COMPOUND NUCLEI

Third International Workshop on Compound-Nuclear Reactions and Related Topics (CNR*11)

September 19-23, 2011, Prague, Czech Republic

110

120

100

90

80

70170

proton nuber

ne

utr

on

nu

mb

er

180 190110 120 130 140 150 160

92U / Tα = 4.5·109 a

82Pb / stable

Bi

Th

Macroscopic theory (charged liquid drop model)

TSF = 1.0·1016 a

102No / Tα ≈ 2 s. TSF ≈ 10-7 a

Z=106?

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

Yuri Oganessian “Heaviest Compound-Nuclei”(CNR*11) , September 19-23, 2011, Prague, Czech Republic

Neutron number

Pro

ton

n

um

be

r

100 110 120 130 140 150 160 170 180 190

120

110

100

90

80

70

New landsNew lands

New landsNew lands Microscopic theory-5 0 5 10 15 LogT1/2 s

1µs 1s 1h a 1 Ma

114

116

continent

Island ofStability

Peninsula

Sea of Instability

Отмель

106

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”


Compound nuclei excitation energy at the Coulomb barrier

-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

actinides

deformednuclei

sphericalnuclei

Pbneutrons →

pro

ton

s

→

Reactions of SynthesisReactions of Synthesis

U

Pb Bi

Th

Neutron capture

Fusion of massive Ions with Pb-target

nuclei

Cold fusionSince 1975

Lightion fusionwith Act.-

nuclei Hot fusion


Cold fusion cross sections and fusion probabilityCold fusion cross sections and fusion probability

10-30

10-32

10-34

10-36

10-38

102 104 106 108 110 112 114 116 118

A tom ic num ber

Cro

ss s

ectio

ns

(cm

)2

208 209 48P b, B i + C a

Z n70 N i

64 F e

58 C r

54

T i

5010-30

10-32

10-34

10-36

10-38

102 104 106 108 110 112 114 116 118

A tom ic num ber

Cro

ss s

ectio

ns

(cm

)2

K . M orita et al., J. Phys. Soc. Jpn, (2004) 2593.

S. Hofm annRep. Prog. Phys., 61 (1998) 639

208 209 48P b, B i + C a

Z n70 N i

64 F e

58 C r

54

T i

50

150 200

100

10-2

10-4

10-6

10-8

C ou lom b repu ls ion

Fu

sion

pro

bab

ility

1 5010050

Z .Z / A +A1 21/3 1 /3

200 250 300

208 16P Ob +

48Ca

Zn70

Ni

64

Fe

58

Cr

54

Ti

50

1 event / year

SHE

Ex=12-15 MeVCold fusion Act.+48Ca

Z=112-118Z=112-118

Ex=40-45 MeVHot fusion

No

Rf

22Ne26M g34S (5n)

Db

Sg

Hs

Bh

Ds

10-30

10-32

10-34

10-36

10-38

4n

-cro

ss

sec

tio

n (

cm

)2

140 150

152 162

180160 170Neutron num ber

48Ca

112

114

116

114

116

118

120

184

σxn ~ (Γn / Γf)x;

х – number of neutrons

(Γn / Γf) ~ exp (Bf – Bn)

Bf = BfLD + ΔEShell

0

Cross sectionsCross sections

Yu.

Oga

ness

ian

2011

-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

Pb

neutrons →

Cold fusionCold fusion

Act.+48CaAct.+48Ca

prot

ons

→

Reactions of SynthesisReactions of Synthesis

U

P b B i

T h

Neutron captureNeutron capture

HotfusionHot

fusion

Yu. Oganessian “Nuclei from Island of Stability of SHE” M-Lakes Conference Sept. 11-18, 2011, Poland

Targets from the n-rich isotopes of the elements

heavier than 238U

Intense ion beam of the rare isotope

- 48Са

DecaychainsDecaychains

184

244Pu, 248Cm +48Ca Z=116

114

112

110

Talk at the Meeting of RAS, Nov.,2000

170 μs

0.7 ms

114

11s

0.5 min

2.5 s

0.06 s

Yu.

Oga

ness

ian

201

1

Deformedshells

Sphericalshells

A/Z Setup Laboratory Publications

283112 SHIP GSI Darmstadt Eur. Phys. A32, 251 (2007)

283112 COLD PSI-FLNR (JINR) NATURE 447, 72 (2007)

286, 287114 BGS LRNL (Berkeley) P.R. Lett. 103, 132502 (2009)

288, 289114

292, 293116

TASCA

SHIP

GSI – Mainz

GSI Darmstadt

P.R. Lett. 104, 252701 (2010)

Eur. Phys. (to be published)

Confirmations 2007-2010


Odd-Z Superheavy Nuclei

Synthesis of Isotopes with Z =113, 115

and 117 in 2010

Experiments on the synthesis of element 115 in the reaction 243Am(48Ca, xn)291−x 115

Yu. Ts. Oganessian et al., PRC 69, 021601(R) (2004)

RAPID COMMUNICATIONS

spherical

deformed

Yu.

Oga

ness

ian

2011

Reaction: 249Bk + 48Ca → 297117* → 294-293117 + 3-4n

T1/2=320d

high neutron flux HFIR (ORNL)

Yu.

Oga

ness

ian

2010

high beam intensity of 48Ca-projectilesU-400 (JINR)

DGFRS

High efficiency of separation1 SH-atom/1012 products

Synthesis of Element 117

The Bk-249 was produced at ORNL (USA) by irradiation: of Cm and Am targets for approximately 250 days by thermal-neutron flux of

2.5 1015 n/cm²·s in the HFIR (High Flux Isotope Reactor).

Total dose:

4.3 1022 n/cm²

Yu.

Oga

ness

ian

2010


22.2 mg of Bk-249

Yu.

Oga

ness

ian

2010

50 Ci50 Ci


0 5 10 15 20 25 30 35 40 45 500

5

10

15

20

25

30

27 1 10 20 30 40 50

10

20

30

0

Bea

m c

urre

nt (

eA

)

1 p A

Yu.

Oga

ness

ian

2010

0 5 10 15 20 25 30 35 40 45 50268269270271272273274275276277278

27 1 10 20 30 50

+_0.

75 M

eV

A ugustJ uly Se p te m be r

Ene

rgy

(Me

V)

273

269

277

Tim e (d )

E* =39. 2 M eV

40

Beam dose: 2.4·1019

48C a-ions

ro ta ting entrancew indow

gas-filledcham ber

detec to rs ta tion

reco ils

pos ition sensitives trip de tecto rs

TO F -de tecto rs

“veto ” de tecto rs

22.50

S H reco il

s ide detec to rs

Dubna Gas-Filled Recoil SeparatorDubna Gas-Filled Recoil Separator

Transmission for: EVR 35-40%

target-like 10-4-10-7

projectile-like 10-15-10-17

Registration efficiency:

for α-particles 87%

for SF single fragment 100% two fragments ≈ 40%

beam48Ca

Experimental technique

target

Number of random sequences imitating such decay chain is:

3·10-11

5 events of decay of isotope

293117 were observed in this experiment

1 events of decay of odd-odd

isotope294117

and

Yu.

Oga

ness

ian

2011

Yu.

Oga

ness

ian

2010

118

116

115

114

113

112

111

110

109

108

107

106

105

104

T1/2= 320d

249Bk +48Ca

117

48 new isotopes

6 new superheavy elements


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:

Yu.

Oga

ness

ian

2011

100

110

120

160 170 180 190Neutron num ber N

Pro

ton

nu

mbe

r Z

1 2 3 4 5 6 7 8

Bf (MeV)

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

Yu.

Oga

ness

ian

2011

deformed

▼110

113

▼▼

▼▼

▼▼ 108

cold fusion

▼▼▼

▼

▼

▼

Z=117

Z=112▼ spherical

▼

▼

▼

Calculated fission barrier heights


0.01

0.1

1

10

100

1000

10000

100000

105 110 115 120

Cold fusion

100

Total evaporation residues cross sections

(pb)

Atomic number

Cross sectionsCross sections

48Ca-inducedreactions

SHE

factor ~300

Yu.

Oga

ness

ian

201

1

100

110

120

160 170 180 190Neutron num ber N

Pro

ton

nu

mbe

r Z

1 2 3 4 5 6 7 8

Bf (MeV)

▼▼

▼

▼

Z=117

Z=112▼

▼

▼

Yu.

Oga

ness

ian

2011

spherical

deformed

alpha decayspontaneous fission


Trans-actinides

Superheavy nuclei

“critical” zones

-6

-8

-4

-2

0

2

4

6

8

10

12

14

16

18

Z=112

112

114110

106

106108

104

102

100

98 N 6=1 2

N 5=1 2N 84=1

140 145 150 155 160 165 170 175 180 185N eu tron num ber

Log

T

(s)

SF

TheorySpontaneous fission half-livesSpontaneous fission half-lives

Actinides

48Ca-induced reactions

155

Neutron num ber

Ha

lf-lif

e, T

(s

)

160 165 170 175

118

116

114

112

112

113

113110

110

111

111115

1801 0 -6

1 0 -4

1 0 -2

1 0 -4

1 0 0 1 s

1 m in

1 m s

102

Half-lives of nuclei with Z ≥ 110

Half-lives of nuclei with Z ≥ 110

Act. + 48Ca

N=162

available for chemical

studies


Yu.

Oga

ness

ian

2011

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

Although SHN are at the limits of Coulomb stability,

• shell stabilization lowers ground-state energy,

• creates a fission barrier,

• and thereby enables SHN to exist.

The fundamentals of the modern theory for mass limits of nuclear matter were given experimental verification.

-2-2

-3

-3

-6

-5

-5

-7

-4

-4

-4

-14

SHE

U

Pb Bi

Th -2-2

-3

-3

-6

-5

-5

-7

-4

-4

-4

-14

120 130 160140 170150 18080

90

100

110

120

190

SHE

U

Pb Bi

Th

neutrons →

prot

ons

→

Nuclear structure and decay properties of the

SHNNuclear Physics

Chemical properties of the SHEChemistry

Search fornew shells

Nuclear theory

Search for SHE in Nature

Astrophysics

Electronic structure of SHE-atomsAtomic Physics


Z=117N=175

T1/2=100 ms

T1/2=1 ms

Z=118N=174

FLNR, JINR (Dubna) ORNL (Oak-Ridge, USA) LLNL (Livermore, USA)

RIAR (Dimitrovgrad, Russia)

Vanderbilt University (Nashville, USA)

Collaboration

Yu.

Oga

ness

ian

2010

Thank you

Reactions of Synthesis and Decay Properties of Superheavy Elements Yuri Oganessian Flerov Laboratory...

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Transcript of Reactions of Synthesis and Decay Properties of Superheavy Elements Yuri Oganessian Flerov Laboratory...