SYNTHESIS OF SUPERHEAVY

ELEMENTS USING THE MASS

SPECTROMETER “MASHA”

• Alejandro Blanco González, High Institute of Technologies and Applied Sciences, Havana.

• Linina Jurbandam, University of The Witwatersrand, Johannesburg.

Supervised by Dr L. Krupa

23th September 2016.

Objectives:

1. Familiarization of the MASHA installation and uses.

2. To measure the alpha decay of Hg and Rn isotopes, produced in fusion reactions in the focal plane of mass spectrometer.

40Ar+natSm→nat-xnHg+xn 40Ar+166Er→206-xnRn+xn

2

U-400M Accelerator

3

MASHA: Mass Separator of Heavy Atoms

4

MASHA: Mass Separator of Heavy Atoms

Incoming beam from U-400M cyclotron

MASHA allows to detect alpha decays and spontaneous fission simultaneously at the mass to charge ratio separation of SHE’s (Super Heavy Elements)

On-Line separation of nuclides with half lives from 0.6s to 30s

High separation energy needed for reaction with low cross sections.

SHE are synthesized via complete fusion reaction of double-magic nucleus 48Ca

5

MASHA- Installation

Secondary ion Source exits ECR

D1- Caught into field Of Pre separation magnet (10°)

Q1and Q2- Quadrupole lenses focuses the beam horizontally and vertically

D2 Separation Magnet

F1- Beam focuses at the first focal plane.

Q3- Sextupole Magnet

D3a and D3b- Main Separation Magnets

Beam reflected vertically by electrostatic mirror at a potential of 2.52kV

1

D1 Q1 Q2D2

Q3S1

D3aD3b

S2

23 4

Пучок ионов

6

Silicone Detector

1

2

3

A photo of a well-type detector. Focal plane (1) consist of 3 crystals 64 strips each.

Side and lateral detectors (2,3) are crystals which have 16 strips each.

Signal from

Si detector

strips

recorded

Preamplifi

er

Channel

Driver

Amplifier

Analogue

Digital

Converters

Main Computer

7

Shape evolution in Fusion-Fission reactions

*Elastic scattering

*Coulomb excitation

*Quasi-elastic scattering

*Deep-inelastic scattering (SHE)

* Incomplete pulse transfer

* Fast-fission

*Quasi-fission

* Fusion → CN → Fission

* Fusion → CN → de-excitation (n,)→ ER

In dependence on impact

parameter

and projectile energy :

ER n

n n

Quasi-fission

CN fission

touching point

capture

Compound nucleus n

Quasi-elastic& Deep-inelastic

8

Data Analysis

60

80

100

120

140

160

180

200

4947

5358

5769

6179

6590

185Hg

(49.1 s)184

Hg(30.9 s)

183Hg

(9.4 s)

182Hg

(10.83 s)

181Hg

(3.54 s)

channel

En

erg

y (k

eV

)3.0005.167

163.0

366.0

569.0

772.0

975.0

Color Scale Title

180Hg

(2.58 s)

40Ar + 144-natSm → 184-nat-xnHg+xn Ebeam=240 MeV

9

5000 5500 6000 6500

0

20

40

60Q = 6119 [0.48]

Counts

Energy (keV)

180Hg (Energy = 6120 keV)

176Pt (Energy = 5750 keV)

Q = 5753 [0.40]

5000 5500 6000

0

40

80

120

160

200

240

Q= 5517 [0.056]

Q= 6006 [0.30]

177Pt (Energy = 5500 keV)

Counts

Energy (keV)

181Hg (Energy = 6000 keV)

5000 5200 5400 5600 5800 6000

0

100

200

300

400

500

600Q = 5867 [0.152]

Co

unts

Energy (keV)

182Hg (Energy = 5860 keV)

178Pt (Energy = 5450 keV)

Q = 5446 [0.046]

5000 5200 5400 5600 5800 6000

0

100

200

300

400

500

600

179Pt decay [0.0024]

Q = 5904 [0.117]

Counts

Energy (keV)

183Hg (Energy = 5890 keV )

5000 5200 5400 5600 5800

0

200

400

600

800

1000

1200

1400

1600

1800

181Pt decay [0.00074]

Q = 5653 [0.06]

Counts

Energy (keV)

185Hg Energy = (5650 keV)

5000 5200 5400 5600 5800

0

50

100

150

200

250

180Pt decay [0.0030]

Q= 5535 [0.0126]

Co

unts

Energy (keV)

184Hg (Energy = 5530 keV)

10

Data Analysis

60 80 100

120

140

160

180

7239

7102

6964

6826

6688

6550

205Rn

(170 s)

204Rn

(1.24 m)202

Rn(10 s)

203Rn

(40 s)

Channel

Ene

rgy

(keV

)

5.667

147.0

329.0

511.0

693.0

875.0

Color Scale Title

201Rn

(7.1 s)

40Ar+166Er→206-xnRn+xn Ebeam=198 MeV, Tcatcher = 1600 oC

11

5500 6000 6500 7000

0

200

400

600

800

1000

1200

1400

1600

1800

2000Q = 6725 [0.80] (7.1 s) , 6773 [0.90] (3.8 s)

Counts

Energy (keV)

201Rn (Energy = 6760 keV)

197Po (Energy = 6380 keV)

Q = 6383.4 [0.84] (25.8 s)

5600 5800 6000 6200 6400 6600 6800

0

500

1000

1500

2000 Q = 6639.5 keV [0.90]

Co

unts

Energy (keV)

202Rn (Energy = 6630 keV)

198Po (Energy = 6180 keV)

Q = 6182.0 keV [0.57]

5000 5200 5400 5600 5800 6000 6200 6400 6600 6800

0

100

200

300

400

500

600

Qa = 6059 [0.39] (4.17 m)

203Rn (Energy = 6550 keV)

Co

unts

Energy (keV)

199Po (Energy = 6060 keV)

Qa = 6549.0 [0.8] (28 s), 6499.3 [0.66] (45 s)

5000 5200 5400 5600 5800 6000 6200 6400 6600

0

50

100

150

200Q = 6418.9 [0.73]

Co

unts

Energy (keV)

204Rn (Energy = 6400 keV)

Q = 5861.9 [0.111]

200Po (Energy = 5860 keV)

5000 5200 5400 5600 5800 6000 6200 6400

0

10

20

30

40

50

Q = 6262 keV [0.23]

Counts

Energy (keV)

205Rn (Energy = 6270 keV)

Q = 5786 keV [0.029]

201Po (Energy = 5790 keV)

12

Conclusion

The parts of the installation were described and understood.

The energy spectra of the escaped α-particles were measured at the focal plane via the silicon detector system.

13

Thank You for Your

Attention 14