MASHAs tale: Determination of masses and nuclear physical - - PowerPoint PPT Presentation

Determination of masses and nuclear physical properties of heavy and superheavy elements using MASHA spectrometer

Starring: Kostadin Zashev (BG) Directed by: Luboš Krupa Antonín Opíchal (CZ) MASHA group Robert Poenaru (RO) Josef Havlík (CZ) Flerov Laboratory of Nuclear Reactions Petr Štaffa (CZ) JINR, Dubna, Russia Lukáš Kouřil (CZ)

MASHAs tale:

MASHA main capabilities

• The mass identification of super heavy

elements.

• Measure the mass of synthesized super

heavy elements.

• Detect the alpha and beta decay of

synthesized super heavy elements .

• Detect spontaneous fission of synthesized super heavy

elements.

• To define the efficiency and operation speed of the given

technique and relative yields of isotopes in the test reactions.

MASHA SETUP

General ion-optical parameters: Range of energy variation, kV 15-40 Range of Br variation, Tm 0.08-0.5 Mass acceptance, % +/-2.8 Angular acceptance, mrad +/-14 Diameter the ion source exit hole, mm 5.0 Horizontal magnification at F1/F2 0.39/0.68 Mass dispersion at F1/F2, mm/% 1.5/39.0 Linear mass resolution at F1 75 Mass resolution at F2 1300 The proposed setup is a combination

• f the so-called ISOL method of

synthesis and separation of radioactive nuclei with the classical method of mass analysis, allowing mass identification of the synthesized nuclides in the wide mass range.

MASHA main components

Material of the catcher – flexible graphite Operating temperature of hot catcher – 1800-2000оС Delivery time of nuclides to the ECR ion source ~ 2 s

ECR ion source Hot catcher Target Beam line Recoil transport

Heavy ion beam Target Hot catcher (graphite) 1

TO

12, 114 ECR Heater Separating foil

Focal plane silicon multi strip detector

Controlling and monitoring system of MASHA

• made in LabVIEW (graphical programming enviroment)
• using the principle called “Virtual Instrumentation“

(complicated hardware is replaced by software)

• Virtual Instruments (VI) are programs, which are built in LabVIEW
• user interface looks like real instruments with switches, knobs,

signalization, indicators etc.

Each VI consists of 2 main parts: 1) Front Panel (user interface) 2) Block diagram (graphical code)

Advantages of LabVIEW

• very easy to analyze some graphical shapes, compared with

structural text code

• so LabVIEW is:
• easy to learn
• good for communication between developers

and engineers

• clear for application building
• specialization for physical experiments and automation
• easy to realize communication with instruments via serial

interface, USB, GPIB, LAN (LXI), ...

• signal proccesing and analyzing
• colour resolution of various data types

Control application for MASHA

Controlling the power supply

• communication via RS-485 using device to create virtual COM ports
• low level functions from VISA palette (inicialization, read, write, etc.)
• non-standard commands according communication protocol of voltage

supply: U1 - to set voltage, with value (eg. U1300 to set 300 V) I1 - to read current value (μA)

Communication with the oscilloscope

• communication via USB 2.0
• a lot of instruments drivers are available at
• fficial national instrument webpage:

www.ni.com

• downloading these drivers could save a lot of

time

• drivers (higher level functions) consist of basic

function (low level functions)

Data analysis

The synthesis of mercury and radon isotopes was carried out in the following reactions: 40Ar + 144Sm → 184-xnHg + xn,

40Ar + 166Er → 206-xnRn + xn

The first step is to detect alpha decay of Hg isotopes in the focal plane of spectrometer obtained in the fusion - evaporation residue reactions. Because the 112 element is a chemical analog to mercury it would be a very good test of the whole method. The same process of fusion-evaporation residue reactions is used for Rn isotopes (The chemical properties of 114 are between Hg and inert gases).

Production of Hg isotopes

In the 40Ar + natSm experiment the target width was 0,63 mg·cm-2 (in terms of Sm) and the beam energy of 40Ar in the half thickness of the target was between 142-202 MeV. The total beam dose passed through the target was 3,7·1017 ions.

Production of Rn isotopes

Radon isotopes were produced in the fusion evaporation residue reactions 40Ar + 166Er at the beam energies between 147-196 MeV. The target thickness was 0,67 mg·cm-2 (in terms

• f Er), isotopic purity of the target was 98%.

The synthesis of 184Hg and 204Rn isotopes

40Ar + 144Sm

→ 184Hg

184Hg (30,6 s) → 182Au (15,6 s)

Beta decay (98,89%)

→ 180Pt (52 s)

Alpha decay (1,11%)

40Ar + 166Er → 204Rn + 2n 204Rn (1,17 min) → 200Po (15,6 s)

Alpha decay (73%)

→ 204At (52 s)

Beta decay (27%)

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190

4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 6.8

186Hg (1.4m) 185Hg (21s, 49s) 184Hg (30.6s) 180Hg (2.56s) 181Hg (3.6s) 182Hg (10.8s) 183Hg (8.8s) 40Ar+Sm, Ebeam= 240 MeV

Strip

Energy [ MeV ]

2.000 6.000 10.00 14.00 18.00 22.00 26.00 30.00 34.00 38.00 42.00 46.00 50.00

40Ar + 144Sm, Ebeam = 240 MeV, T catch = 1600oC

Energy spectrum of alpha particles for mass number A=182 and A=202 A=203 A=204

Conclusion

The isotopes of Hg and Rn were produced in the fusion-evaporation residue reactions 40Ar + natSm and 40Ar + 166Er. Their chemical properties (adsorption energy on the surface) are close to those of 112 and 114. The spectra

• f alpha particles after decay of isotopes in the focal plane

were measured by silicon well-type detector. The operation speed of the setup was estimated ≤ 4 seconds. The obtained results indicate that these achieved parameters of mass-spectrometer “MASHA” are close to designed values.

Island of stability

Thank you to not ask any question! 