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Status of the experiments on the synthesis of Element 117

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1 Status of the experiments on the synthesis of Element 117
Yuri Oganessian FLNR (JINR) for collaboration 107th Session of the JINR SCIENTIFIC COUNCIL 18–19 February 2010, Dubna

2 Collaboration FLNR, JINR (Dubna) ORNL (Oak-Ridge, USA)
Yu. Oganessian 2010 FLNR, JINR (Dubna) ORNL (Oak-Ridge, USA) LLNL (Livermore, USA) IAR (Dimitrovgrad, Russia) Vanderbilt University (Nashville, USA)

3 at the Colloquium, ORNL, 02/10/05
249Bk +48Ca α1 α2 α3 α4 α5 α6 α7 3-4n RAPID COMMUNICATIONS 3-4n PHYSICAL REVIEW C 69, (R) (2004) Experiments on the synthesis of element 115 in the reaction 243Am(48Ca, xn)291−x 115 243Am + 48Ca Yu. Ts. Oganessian et al., Yu. Oganessian 2010 Yu.O. “SHE”, at the Colloquium, ORNL, 02/10/05

4 October 2-3, 2008, Nashville, USA Symposium
“Prof. Joseph Hamilton: 50-year career at Vanderbilt University”. October 2-3, 2008, Nashville, USA Yu. Oganessian 2010

5 Scientific Collaboration and Material Transfer Agreement № 500-09-01
between the UT-Battelle, LLC, the Management and Operating Contractor for Oak-Ridge National Laboratory, Oak Ridge, TN, USA and the Flerov Laboratory of Nuclear Reactions Joint Institute for Nuclear Research Dubna, Russia Yu. Oganessian 2010 The material produced by ORNL will be used for carrying out a joint experiment on the synthesis of new super-heavy chemical element Z=117 of the Periodic System of Elements for studying the features of this element and its radioactive decay products and for studying the formation of super-heavy nuclei in heavy-ion reactions. UT-BATTELLE, LLC JINR Name: K.P. Rykaczewski Name: Yu.Ts. Oganessian Spectroscopy task leader Scientific leader of FLNR Deputy Director J.R. Roberto Director A.N. Sissakian March 02, March 12, 2009

6 Yu. Oganessian 2010 Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

7 249Bk (320d) Cross sections (pb) 3n 4n Compound nucleus mass number
Z.H. Liu and Jing-Dong Bao. Phys. Rev., C80, (2009) 249Bk (320d) Yu. Oganessian 2010 Cross sections (pb) 3n 4n Compound nucleus mass number Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

8 Dubna Gas-filled Recoil Separator
Reaction: 249Bk Ca → * → n high intensity of 48Ca beam (~1.5 pμA) beam dose ≥3·1019 U- 400 FLNR, JINR Yu. Oganessian 2010 T1/2=320d Separation, Detection & Identification 1 SH-atom / 1012 reaction products DGFRS Dubna Gas-filled Recoil Separator high neutron flux HIFR, ORNL chemical separation from 252Cf (factor >108) target preparation 36cm2 0.25 μm BkO μmTi IAR, Dimitrovgrad 3·108 4.5·1019 1event|Z=117→ 0.14pb

9 at ORNL (USA) by irradiation: of Cm and Am targets for
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 neutrons/cm²·s in the HFIR (High Flux Isotope Reactor).  Yu. Oganessian 2010 Irradiation ends December 2008 Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

10 50 Ci 50 Ci The purified product contained 22.2 mg of Bk-249,
Yu. Oganessian 2010 50 Ci 50 Ci The purified product contained 22.2 mg of Bk-249, approximately 1.7 ng of Cf-252, and no other detectable impurities. Chemical isolation of the Bk-fraction May 2009 Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

11 Target 310 μg/cm2 BkO2 on 1.5 μm-Ti foil ω = 1700 rpm 6 cm2 600 120 mm
Yu. Oganessian 2010 120 mm target-making June 2009

12 Experimental technique
Dubna Gas-Filled Recoil Separator Yu. Oganessian 2010 Transmission for: EVR 35-40% target-like projectile-like Registration efficiency: for α-particles 87% for SF single fragment 100% two fragments ≈ 40% beam 48Ca target 249Bk Experiment was started July 27

13 from July 27 to October 23, 2009 Beam dose: 2.4·1019
Yu. Oganessian 2010 First run: from July 27 to October 23, Beam dose: 2.4·1019

14 a a low-background detection scheme 249Bk target focal plane
detector array separator Yu. Oganessian 2010 9.79 MeV 22.09 mm 0.24 s 189.4 MeV 22.01 mm 31.66 s 10.25 MeV 22.20 mm 0.51s 10.91 MeV 22.16 mm 53.01 ms 9.96 MeV 22.04 mm 48Ca 4m 117 293 a 1 10.7–11.4 MeV Δy=y1-y0 ≤ 2.2 mm ≤ 132 ms 7–15 MeV y0 the beam was switched off SF a 2 3 Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

15 α1 SF α3 α2 Spectra of the α-like signals 80 h 1680 h 7·10-5/s
Yu. Oganessian 2010 Spectra of the α-like signals beam-off beam-on 252,254Cf 80 h 1680 h 7·10-5/s Spectra of fission-like signals 1.5·10-7/s 111 SF 113 115 117 α1 α2 α3 beam-on 1680 h 80 h 10-3/s 211Po 214Po 213Po 212Po (α+e-) (α+e-) 212Po beam-off 2·10-6/s per strip / position

16 Cross sections 249Bk + 48Ca 4n 3n ACN=297 Cross sections (pb) Calc.
Yu. Oganessian 2010 249Bk + 48Ca 293 Calc. Cross sections (pb) 4n Y. Abe et al., Int. J. Mod. Phys. 17 (2008) 2214 294 V.I. Zagrebaev & W Greiner Phys. Rev. C78, (2008) 3n Z.H. Liu & Jing-Dong Bao Phys. Rev. C80, (2009) Excitation energy of the * (MeV) Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

17 Ex=39 MeV (48Ca,4n) Ex=35 MeV (48Ca,3n)

18 3n 4n

19 249Bk +48Ca Decay Decay chains chains 48 nuclides T1/2= 320d
Collaboration: FLNR (Dubna) – ORNL (Oak-Ridge) – LLNL (Livermore) – IAR (Dmitrovgrad) Vanderbilt University (Nashville) 48 nuclides Yu. Oganessian 2010 19

20 Spontaneous fission half-lives
Actinides Trans-actinides Superheavy nuclei 20

21 α-decay “critical” zones Spontaneous fission Z=117 Z=112
P. Moller et al., Phys. Rev., C79, (2009) α-decay Spontaneous fission Yu. Oganessian 2010 Z=117 “critical” zones Z=112

22 PRELIMINARY Theory & Experiment blue – cold fusion black – Act. + 48Ca
red – 249Bk. + 48Ca 117 5% Yu. Oganessian 2010 PRELIMINARY deformed spherical

23 PRELIMINARY Alpha decay energy Half-lives blue – cold fusion
black – Act.+48Ca red – 249Bk+48Ca PRELIMINARY Yu. Oganessian 2010 Alpha decay energy Half-lives Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

24 Cross sections 208Pb+48Ca 226Ra+48Ca 249Bk+48Ca Ex≈ 40 MeV
Yu. Oganessian 2010 226Ra+48Ca 249Bk+48Ca

25 Experiment is still going on…

26 Subsequent research Chemistry of Element 113

27 249Bk(320d) + 48Ca 243Am(7370y) + 48Ca Periodic Table of Elements
Yu. Oganessian 2010 more and more inert? Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna 27

28 249Bk + 48Ca Isotopes of Element 113 243Am + 48Ca 209Bi + 70Zn
237Np + 48Ca 249Bk + 48Ca T1/2 JINR (Dubna) - - LLNL (Livermore) - - ORNL (Oak-Ridge) collaboration 0.07s 0.5s 5.5s σ =4.2pb σ =1.3pb Isotopes of Element 113 209Bi + 70Zn RIKEN (Tokyo) 0.24 ms σ =0.03pb Yu. Oganessian 2010 Yu. Oganessian. “Status of the experiment on the synthesis Z=117”. JINR SC, Feb.18-19, 2010, Dubna

29 Adsorption enthalpy of elements 112 through 115 (in kJ/mol)
Hg Tl Pb Bi Teflon 13.2 19.7 13.7 15.2; 12.5 ice 26.27 - 26.3 quartz 422a 26b 1162d 1145d 202e gold 982 c 2405d 235f (305) estimate Red – experiment: a) Soverna, PSI Report 2004, p. 8; b) A. Yakushev, et al. c) S. Soverna et al. Radiochim. Acta, 93, 1-5 (2005). d) S. König, et al. PSI Annual Report 2007? e) F. Haennsler, et al PSI Annual Report 2004, p. 9. f)  21 (Haenssler); -222  8 (Fan); 242 on the picture; F. Haenssler et al., PSI AR, 2005, p. 3. g) R. Eichler et al. Angew. Chem. Int. Ed. 47, 1-6 (2008). h) R. Eichler and M. Schädel, J. Phys. Chem. B 106, (2002). k) R. Eichler, private commun. Black- calculations. Blue – estimates from the calculations for the dimer with respect to the exp. for the homolog. Green ? – with respect to the exp. for Rn based on the calculations Yu. Oganessian 2010 112 113 114 115 Teflon 13.3 14.0 10.4 14.1; 12.2 ice 26.4 - 20.20 quartz 43.4 ? (21.0 ideal) gold 62 52+4-3g 158.6  99.4 (223.6) estim

30 249Bk(48Ca,4n)293117→α→293115 →α→289113[5.5s] →α→ 283Rg[26s]
Reaction: 249Bk(48Ca,4n)293117→α→ →α→289113[5.5s] →α→ 283Rg[26s] Yu. Oganessian 2010 Au SiO2

31 Thanks for your attention

32


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