Spectroscopic investigations of isotopes near N=126 shell closure - - PowerPoint PPT Presentation

Spectroscopic investigations of isotopes near N=126 shell closure using the multinucleon transfer reaction

Ľuboš Krupa - Supervisor 1

Adam Broniš - Slovakia Lukáš Kaňka - Czech Republic Mădălina Mihaela Miloi - Romania

Student Practice FLNR,JINR Dubna 22.7. 2016

Main goals

• The aim of the project was analysis of data from

experiment and to determine cross sections of Radon isotopes. These results could provide a better understanding of structure and properties

• f superheavy elements and information about

their synthesis.

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Content

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• 1. Transfer reactions
• 2. Experimental setup
• 3. Data analysis
• 4. Conclusion

Transfer reactions

• Direct -one stage proces
• Non-uniform angular distibution of

products (conservation of angular momentum)

• Time scale

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s 10 22

n p X b (impact factor) Projectile Target nucleus Transfered cluster X

Three body problem – projectile, target, cluster DWBA (Distorted wave Born approximation) - incoming and outcoming planar waves are distorted by the nucleus due to the optical model

• Different isotopes of radon (with different masses) are produced.

Mass differences and energies are used for their separation and identification.

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Transfer reactions

Two types of transfer reactions were used in the experiment:

.... Rn Pb Ca

X 208 48

.... Rn Pu Ca

X 242 48

Projectils Targets Multinucleon transfer products

X=211,212,219,220,221,222

Experimental setup

• measuring the masses of synthesized superheavy

element isotopes

• simultaneously measuring their

decays and spontanneous fission

• determination yields of isotopes

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MASHA (Mass Analyzer of Super Heavy Atoms) capabilities:

Experimental setup

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Mass separator MASHA

Dipole magnets Quadrupole lenses Hot catcher Focal plane Detector ECR ion source

Experimental setup

8 Hot catcher Target Graphite foil Heater Separating foil After emission from the target the reaction products passed through the separating foil and stopped in a graphite foil heated up to 2000K. Then the products diffused from the graphite into the vacuum of the hot catcher and continued to ECR source. to ECR

Experimental setup

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Beam focusing lenses Bending magnet for separation Beam correcting elements Pair of main magnets for ion separation and mass resolution Electrostatic deflector for energy separation Isotopes are separated according to their masses and finaly implanted in focal plane silicon detector Different isotopes

• f radon

Experimental setup

10 Focal plane silicon detector Frontal part of the detector - 192 strips All strips are equally thick 300 micrometers. Energy resolution for particles is approximately 30 keV. During measurements just the frontal partal of detector was used. Efficiency was due to detector geometry. 64 strips 64 strips 16 strips 16 strips

% 47

Data analysis

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Strip

50 100 150 4 5 6 7 8 9 192

E [MeV]

Rn

211

Rn

212

Rn

219

Rn

220

2D spectra of the particle energy vs strip number in the frontal part of the detector

Data analysis

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B 2π σ p N

Data analysis

We used system of differential equations simulation to get the counts of isotopes: 1. 2. 3. 4. 13

Simulations

(t) N ) ( N λ dt ) ( dN

p 1 1 1

t t 0.47 * ) ( N λ ) ( N λ dt ) ( dN

1 1 2 2 2

t t t ) ( N λ ) ( N λ dt ) ( dN

2 2 3 3 3

t t t ) ( N λ ) ( N λ dt ) ( dN

3 3 4 4 4

t t t

t t 1 1 α1

N * λ N

………………

B I * k (t) N

p p

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Data analysis

• 1. Decay simulation
• 2. Decay simulation
• 3. Decay simulation
• 1. Decay data
• 2. Decay data
• 3. Decay data

Time [s] Counts

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Conclusion

The simulation by means of the system of differential equations proved to be a valuable tool for analysis of this particular

• problem. It corresponds with the data

from the experiment and provides the real count of particles on the detector. Based

• n the count of all isotopes cross-sections

can be subsequently determined.

Thank you for your attention.

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