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Search for Superheavy element and Role of Fission Dynamics. Z>92 (Heaviest Element in Nature) and upto Z=100-101 achieved by n irradiation or p, a, and d bombardment in Cyclotron (1940-1955) (LBL) Z=102-106 by Light or Heavy-ion induced Fusion

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Z>92 (Heaviest Element in Nature) and upto Z=100-101

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Z 92 heaviest element in nature and upto z 100 101

Search for Superheavy element and

Role of Fission Dynamics

  • Z>92 (Heaviest Element in Nature) and upto Z=100-101

    achieved by n irradiation or p, a, and d bombardment in

    Cyclotron (1940-1955) (LBL)

  • Z=102-106 by Light or Heavy-ion induced Fusion

    -evaporation using heavy element targets (1958-1974)

    Z=107-112 Heavy ion inuced fusion 208Pb,209Bi targets

    (GSI)

    Identified by recoil separation technique and connecting

    to known daughter decay after implanting into Si strip

    detectors.

  • Z=112-116 48Ca+Pu,Am,Cm,Cf (JINR, Dubna)

    Identified by gas filled separators and Si strip setectors

SERC Course


Z 92 heaviest element in nature and upto z 100 101

SERC Course


Z 92 heaviest element in nature and upto z 100 101

SERC Course


Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

Cross-section data and extrapolated values for cold-fusion

Reactions (1n -evaporation channel)

Cross-section increases with increasing isospin

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

E*~33 MeV

E*~34-38 MeV

48Ca+244Pu->289114+3n

48Ca+244Pu->288114+4n

48Ca+242Pu->287114+3n

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Z 92 heaviest element in nature and upto z 100 101

Yury Ts. OganessianPure Appl. Chem., Vol. 76, No. 9,

pp. 1715–1734, 2004.

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

48Ca+244Pu

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

The flight time of the reaction products through SHIP is 2 ms.

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

∙ Cold Fusion 208Pb and 209Bi targets bombarded by the following projectiles:

48Ca, 50Ti, 54Cr,58Fe, 62Ni, 64Ni, 70Zn, 76Ge, 82Se, and 86Kr.

∎ Hot Fusion 48Ca projectiles bombarded targets of 238U, 244Pu, 243Am,

245Cm, 248Cm, and 249Cf,

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Z 92 heaviest element in nature and upto z 100 101

BLDf gradually disappears

Spherical

Deformed

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Z 92 heaviest element in nature and upto z 100 101

Fission barrier calculations of Smolanzuk et al.

106Sg has highest barrier with half life of 3 hrs

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

For Z1Z2>1000 to 1650 depending

on the value of the charge

asymmetry, Zp/ZT.

Extra push energies

Swiatecki

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Z 92 heaviest element in nature and upto z 100 101

No hindrance

Onset of fusion limitation

Due to Extra push energies

Effective fissility : weighted mean of mono-nuclear and binary

With weight for binary taken as 1/3

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

Injection direction

Difference in energy

Between touching

Point and saddle point

Small due to shell structure

Of Ca and Pb

Fusion area inside

Saddle point

All trajectories reaches fusion

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Z 92 heaviest element in nature and upto z 100 101

Quasi-fission is

dominant

Extra pocket in mass

Symmetric region

Deep

Quasi-

fission

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Z 92 heaviest element in nature and upto z 100 101

Evgeni A. Cherepanov

Brazilian Journal of

Physics, vol. 34, no. 3A,

September, 2004

The curve V (Z,L = 0) (for the value of R corresponding to

the pocket) has a few local minima, which reflect the shell

structure in the interacting nuclei.

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Z 92 heaviest element in nature and upto z 100 101

Mass asymm fluctuates

around 0.5 and then

relaxes quickly and

Trajectory move to main

pocket

48Ca+208Pb

EX=50 MeV

Aritomo and Ohta

Pre-print

Nuclear Physics A 744 (2004) 3–14

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Z 92 heaviest element in nature and upto z 100 101

Critical stage

For FF mass

Asymmetries

large

Turning stage

For QF neck develops

and speeds up fission

keeping mass asymm.

For deep QF mass asymm

Relaxed in sub-pocket

At TS

48Ca+244Pu

Ex=50 MeV

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

The smaller formation probability due to inhibition of fusion by competing mechanism:DIC,QF,FF,PEFAsymmetric channels: higher E*

and unfavourable for survival

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Z 92 heaviest element in nature and upto z 100 101

Transition from

FF to QF

Mass distribution for

FF is asymmetric in shape

With peak around 132

QF

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Measurements at lnl legnaro italy

Measurements at LNL,Legnaro (Italy)

470-630 MeV 80Se + 208Pb

372 MeV 56Fe+232Th

288116

470-630 MeV

312124

80Se + 232Th

Measurement of fragment mass and kinetic energy

and neutron correlations

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Z 92 heaviest element in nature and upto z 100 101

Schematics of the setup for Se+Pb,Th experiment

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Z 92 heaviest element in nature and upto z 100 101

80Se+208Pb

470 MeV

80Se+232Th

470 MeV

DIC dominates but significant events around symmetry

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Z 92 heaviest element in nature and upto z 100 101

Se+Pb more asymmetric compared to Se+Th

QF is expected to be more for Se+Th

80Se+208Pb

470 MeV

80Se+232Th

470 MeV

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Z 92 heaviest element in nature and upto z 100 101

higher extra-push energy

in the case of 80Se+232Th

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Z 92 heaviest element in nature and upto z 100 101

80Se+208Pb

288116

80Se+232Th

312124

ν sftot=10±2 for Se+Pb

12±1 for Fe+Th

=17±2 for Se+Th

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Z 92 heaviest element in nature and upto z 100 101

on average of about 0.6 neutron per unit Z

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Z 92 heaviest element in nature and upto z 100 101

an increase of about 0.54 neutron per unit Z

excitation energy gained by the system in its transition from the saddle to the

scission point (the term ΔEx by Hilscher) that is known to show a strong mass

and Z dependence.

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Z 92 heaviest element in nature and upto z 100 101

JINR,Dubna

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Z 92 heaviest element in nature and upto z 100 101

41 detectors of DEMON at Dubna

T. Materna et al. Nuclear Physics A734

(2004) 184-l 87

208±20

QF

FF

A/2±30

The pre-scission neutron multiplicity distribution simulated

using backtracing procedure show two components for Ca+Pu

Whereas for Ca+Pb only one component is seen

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Z 92 heaviest element in nature and upto z 100 101

??

Self-consistent

Connectecd with

known species

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Z 92 heaviest element in nature and upto z 100 101

Change from

Hot fusion to

Cold fusion

For higher N-Z

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Z 92 heaviest element in nature and upto z 100 101

Survival probability

Depends on fissiondelay

And speed of cooling

Mainly by neutron

evaporation

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

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Z 92 heaviest element in nature and upto z 100 101

Expected intensities s-1for neutron-rich radioactive beams

SPIRAL 24Ne 7 x 107

HI based 44Ar 5 x107

PIAFE 78Zn 108

84Ge 2 x108

94Kr 2 x 109

Reactor based

Region beyond Z= 114 needs beam intensities in excess of 1014 s-1.

With MAFF and spallation facility with 100μA proton of 1GeV

Intensities may go up by 3 to 4 orders of magnitude

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Z 92 heaviest element in nature and upto z 100 101

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