1. Synthesis of superheavy elements at FLNR S. DMITRIEV Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, 141980, Russia e-mail: dmitriev@jinr.ru PASIFICHEM 2010, PASIFICHEM 2010, 18 December 2010, Honolulu, Hawaii, USA

2. 2 Cn

3. 3 SHE Cold & hot fusion cross sections fusion survival

4. 4 48 Ca Enrichment up to 68-70% (Lesnoy) isotope production high flux reactors (Oak Ridge, Dimitrovgrad) isotope enrichment 98-99% S-2 separator (Sarov) New ECR-ion source (GANIL, JINR) New separator & detectors (Dubna, Livermore) New target matter technology of the target preparation – 0.3 mg/cm 2 Separation and detection of superheavy nuclei Efforts focused on the synthesis of SHE REACTORREGIMEACCELERATORS ISOTOPE ISOTOPEENRICHMENT TARGET TECHNOLOGY NEWRECOILSEPARATOR

5. FLNR U400 cyclotron

6. v ( A=48 ) = 0.11 c q = 16.5+ v ( A=288 ) = 0.017 c q = 6.2+ Experimental Setup

7. 7 Total detection efficiency: for α-particles…………..83% for SF-fragment…….~ 100% for both fragments……..42% Focal plane detector

8. Number of observed decay chains Element 118 3 Element 116 26 Element 115 4 Element 114 43 Element 113 2 Element 112 8

9. 9 SHE fusion survival Cold & hot fusion cross sections

10. Relatively long half-lives of isotopes of elements 104-116 produced in the reactions with 48 Ca and chemical properties of SHE predicted theoretically permit new experiments aimed at:  the chemical identification of SHE ( 268 Db)  study of their chemical properties (112,114),  determination of masses of the SHE isotopes

11. Number of observed decay chains Element 118 3 Element 116 26 Element 115 4 Element 114 43 Element 113 2 Element 112 8

12. 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  10 15 neutrons/cm²·s in the HFIR (High Flux Isotope Reactor). Irradiation ends December 2008

13. 13 249Bk was produced at High Flux Reactor in Oak-Ridge………...March 09, 2009 22 mg of pure 249Bk was shipped to Moscow……………................June 20, 2009 Arrived at Dimitrovgrad (Russia) for target preparation……………..July 01, 2009 Experiment have started at Dubna…………….....................................July 27, 2009

14. 60 0 6 cm 2 310 μg/cm 2 BkO 2 on 1.5 μm-Ti foil 120 mm ω = 1700 rpm Target target-making June 2009 Yu. Oganessian 2010

15. Dubna Gas-Filled Recoil Separator Transmission for: EVR 35-40% target-like 10 -4 -10 -7 projectile-like 10 -15 - 10 -17 Registration efficiency: for α-particles 87% for SF single fragment 100% two fragments ≈ 40% beam 48 Ca Experimental technique target 249 Bk Experiment was started July 27 2009 Yu. Oganessian 2010

16. First run: from July 27 to October 23, 2009 Beam dose: 2.4·10 19 0.3%

17. 17 2  1  3  113 285 Rg 281 11.14 MeV 7.89 ms 23.16 mm 13.87 MeV str.#10, 12:28 Sep.10, 2009 22.70 mm 9.52 MeV (8.98 +0.54) 291.9 MeV ( 184.8 +7.1) 2.22 s 22.67 mm 4.25 s 115 117 289 293 missing  N=N= ran 1. 10 -3-3 N= ran 1. 10 -5 2  1  3  113 286 Rg 282 4.6 ms 17.19 mm 17.41 mm 13.51 MeV str.#10, 04:50 Sep.18, 2009 17.17 mm 0.017 s 10.34 MeV 204.8 MeV ( 180.0 +24.8 ) 1.16 s 16.45 mm 12.03 s SF 115 117 290 294 9.71 MeV ( 9.17 +0.54 ) 11.08 MeV (6.64 +4.44) N= ran 3. 10 -11 10.25 MeV 2  1  3  113 286 Rg 282 53.01 ms 122.16 mm 22.20 mm 22.09 mm 9.96 MeV str.#8, 04:23 Oct.17, 2009 22.04 mm 0.51 s 189.4 MeV (153 +36) 0.24 s 23.19 mm 76.56 s SF 115 117 290 294 9.79 MeV 10.91 MeV SF 11.89 MeV str.#10, 09:40 Aug.20, 2009 2  1  3  113 285 Rg 281 10.99 MeV 17.01 ms 15.02 mm 15.20 mm missing  203.3 MeV 9.72 MeV 16.17 s 15.40 mm 14.86 mm N= ran 6. 10 -6 40.19 s SF 115 117 289 293 N= ran 3. 10 -11 10.27 MeV (9.03+1.24) 2  1  3  113 286 Rg 282 20.24 ms 13.33 mm 10.90 mm 23.59 mm 9.36 MeV str.#10, 01:37 Oct.23, 2009 13.23 mm 0.42 s 194.0 MeV 13.49 s 23.19 mm 76.56 s SF 115 117 290 294 9.48 MeV 11.00 MeV E x =39 MeV Beam dose: 2.4·10 19

18. 117 297 4n E x =39 MeV E x =35 MeV Beam dose: 2.0·10 19

19. 19 Synthesis of a new element with atomic number Z=117 Yu. Ts. Oganessian, 1) F. Sh. Abdullin, 1) P. D. Bailey, 2) D. E. Benker, 2) M. E. Bennett, 3) S N. Dmitriev, 1) J. G. Ezold, 2) J. H. Hamilton, 4) R. A. Henderson, 5) M. G. Itkis, 1) Yu. V. Lobanov, 1) A. N. Mezentsev, 1) K. J. Moody, 5) S. L. Nelson, 5) A.N. Polyakov, 1) C. E. Porter, 2) A. V. Ramayya, 4) F. D. Riley, 2) J. B. Roberto, 2) M. A. Ryabinin, 6) K. P. Rykaczewski, 2) R. N. Sagaidak, 1) D. A. Shaughnessy, 5) I.V. Shirokovsky, 1) M. A. Stoyer, 5) V. G. Subbotin, 1) R. Sudowe, 3) A. M. Sukhov, 1) Yu. S. Tsyganov, 1) V. K. Utyonkov, 1) A. A. Voinov, 1) G. K. Vostokin, 1) and P. A. Wilk 5) 1 Joint Institute for Nuclear Research, RU-141980 Dubna, RF 2 Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA 3 University of Nevada Las Vegas, Las Vegas, NV 89154, USA 4 Vanderbilt University, Nashville, TN 37235, USA 5 Lawrence Livemore National Laboratory, Livermore, CA 94551, USA 6 Research Institute of Atomic Reactors, RU-433510 Dimitrovgrad, RF (Dated: April 1, 2010) The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes 293 117 and 294 117 were produced in fusion reactions between 48 Ca and 249 Bk. Decay chains involving eleven new nuclei were identified by means of the Dubna Gas Filled Recoil Separator. The measured decay properties show a strong rise of stability for heavier isotopes with Z≥111, validating the concept of the long sought island of enhanced stability for super-heavy nuclei

20. 20 Decay properties of the nuclei in the decay chains of Z=117 isotopes Yu. Oganessian 2010

21. 21 Target ( 249 Bk ;  0,5 mg/cm 2 ) SiO 2 - Ta 800°C (4  ) (4  ) He/Ar (70/30) CHEMISTRY OF THE 113 ELEMENT Au - 113 16 pairs 2.5m 1 L/min

22. 22 Capillary length from target chamber to detector system is 2.5 m

23. 23 16 pairs of gold covered detectors

24. 24 48 Ca + 249 Bk Target 249 Bk (0.5 mg∙cm -2 ) nat Nd (30 μg∙cm -2 ) 48 Ca E mid. target = 252 MeV I ~ 9 eμA Irradiation: - 18.04.2010 – 31.05.2010; target I - 3.5 10 18 ; target II - 5.6 10 18 9.1∙10 18

25. 25 Alpha and SF spectra

26. DGFRS 04 May 2010 10:05:4616 May 2010 02:29:54 Bk-target I Bk-target II 115 290 α2α2α2α2 113 286 8.89 MeV 64.90 s Mt 278 α4α4α4α4 Rg 282 α3α3α3α3 9.52 MeV 6.49 s Bh 274 α5α5α5α5 SF 101.0 + 89.1 MeV 79.25 h α6α6α6α6 8.77 MeV 13.59 min Db 270 249 Bk + 48 Ca 3n 9.62 MeV 117 294 α1α1α1α1 Bot. 8 115 290 9.95(40) MeV 10.23 MeV α2α2α2α2 113 286 9.00(10) MeV 9.43 MeV Mt 278 α4α4α4α4 Rg 282 α3α3α3α3 9.55(19) MeV 9.14 MeV Bh 274 α5α5α5α5 SF TKE = 219(5) MeV 33.4 h α6α6α6α6 8.80(10) MeV 8.43 MeV Db 270 9.63(10) MeV 9.56 MeV 117 294 10.81(10) MeV 11.00 MeV α1α1α1α1 1.3 min 7.4 min 11.0 s 13 s 0.74 s 8.1 s 28.3 s 16 s 0.023 s 1.0 s 112 ms 45 ms 117 297 E* = 35 MeV 1 event 115 290 α2α2α2α2 113 286 9.01 MeV 1.85min Mt 278 α4α4α4α4 Rg 282 α3α3α3α3 Bh 274 α5α5α5α5 SF 98.6 + 88.5 MeV 64.61 h α6α6α6α6 8.64 MeV <1.42 min Db 270 249 Bk + 48 Ca 3n 117 294 α1α1α1α1 Bot. 4 Top 4 26 preliminary

27. DGFRS 04 May 2010 10:05:4616 May 2010 02:29:54 Bk-target I Bk-target II 115 290 α2α2α2α2 113 28 6 8.89 MeV 64.90 s Mt 27 8 α4α4α4α4 Rg 282 α3α3α3α3 9.52 MeV 6.49 s Bh 27 4 α5α5α5α5 SF 101.0 + 89.1 MeV 79.25 h α6α6α6α6 8.77 MeV 13.59 min Db 270 249 Bk + 48 Ca 3n 9.62 MeV 117 294 α1α1α1α1 Bot. 8 115 290 9.95(40) MeV 10.23 MeV α2α2α2α2 113 286 9.00(10) MeV 9.43 MeV Mt 278 α4α4α4α4 Rg 282 α3α3α3α3 9.55(19) MeV 9.14 MeV Bh 274 α5α5α5α5 SF TKE = 219(5) MeV 33.4 h α6α6α6α6 8.80(10) MeV 8.43 MeV Db 270 9.63(10) MeV 9.56 MeV 117 294 10.81(10) MeV 11.00 MeV α1α1α1α1 1.3 min 7.4 min 11.0 s 13 s 0.74 s 8.1 s 28.3 s 16 s 0.023 s 1.0 s 112 ms 45 ms 117 297 E* = 35 MeV 1 event 115 290 α2α2α2α2 113 286 9.01 MeV 1.85m in Mt 27 8 α4α4α4α4 Rg 282 α3α3α3α3 Bh 27 4 α5α5α5α5 SF 98.6 + 88.5 MeV 64.61 h α6α6α6α6 8.64 MeV <1.42 min Db 27 0 249 Bk + 48 Ca 3n117 294 α1α1α1α1 Bot. 4 Top 4 27 preliminary

29. 29 Hg-185 DISTRIBUTION

30. 30 DGFRS Chemistry of the Element 113 115 288 113 284 9.75 MeV 3.6 s Mt 276 Rg 280 9.71 MeV 0.72 s Bh 272 SF TKE = 205(5) MeV 16 h 9.02 MeV 9.8 s Db 268 243 Am + 48 Ca 3n 10.00 MeV 0.48 s α2α2α2α2 α4α4α4α4 α3α3α3α3 α5α5α5α5 α1α1α1α1 10.46 MeV 87 ms 115 289289289289 10.31(9) MeV 10.48 MeV α2α2α2α2 113 285 α3α3α3α3 SF TKE = 218(5) MeV 38 s Rg 281 9.74(8) MeV 9.48(11) MeV 9.96 MeV 117 293 11.03(8) MeV 11.26 MeV α1α1α1α1 7.9 s 1.2 s 0.32 s 0.22 s 21 ms 10 ms 117 297 115 290 9.95(40) MeV 10.23 MeV α2α2α2α2 113 286 9.00(10) MeV 9.43 MeV Mt 278 α4α4α4α4 Rg 282 α3α3α3α3 9.55(19) MeV 9.14 MeV Bh 274 α5α5α5α5 SF TKE = 219(5) MeV 33.4 h α6α6α6α6 8.80(10) MeV 8.43 MeV Db 270 9.63(10) MeV 9.56 MeV 117 294 10.81(10) MeV 11.00 MeV α1α1α1α1 1.3 min 7.4 min 11.0 s 13 s 0.74 s 8.1 s 28.3 s 16 s 0.023 s 1.0 s 112 ms 45 ms 117 297 249 Bk + 48 Ca

31. Experimental program of 2011-2012 Chemistry of 113 element (243Am + 48Ca) Chemistry of 114 element (244Pu + 48Ca) Mass number measurement of 112 - 114 elements 242 Pu( 48 Ca,3n) 287 114(0.5s,α) –> 283 112(4 s) 243Am(48Ca,3n) –> 288 115 (0.1 s, α) –> 284 113(0.5 s)

32. Introduction MA ss S eparator of H eavy A toms The proposed setup is a combination of 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. General ion-optical parameters: Range of energy variation, kV15-40 Range of Br variation, Tm0.08-0.5 Mass acceptance, %+/-2.8 Angular acceptance, mrad+/-14 Diameter the ion source exit hole, mm 5.0 Horizontal magnification at F1/F20.39/0.68 Mass dispersion at F1/F2, mm/%1.5/39.0 Linear mass resolution at F175 Mass resolution at F2 1150

33. Mass-spectrometer MASHA at the beam line of the cyclotron U-400M STATUS of the MASS-SPECTROMETER

34. FIRST EXPERIMENTS Mass identification of 112 и 114 elements synthesized at the reactions Mass identification of 112 и 114 elements synthesized at the reactions 242 Pu( 48 Ca,3n) 287 114(0.5 s) –> 283 112(4 s) Mass identification of 113 elements synthesized at the reaction Mass identification of 113 elements synthesized at the reaction 243 Am( 48 Ca,3n) 288 115 (0.1 s) → 284 113 (0.5 s) FIRST EXPERIMENTS Mass identification of 112 и 114 elements synthesized at the reactions Mass identification of 112 и 114 elements synthesized at the reactions 242 Pu( 48 Ca,3n) 287 114(0.5 s) –> 283 112(4 s) Mass identification of 113 elements synthesized at the reaction Mass identification of 113 elements synthesized at the reaction 243 Am( 48 Ca,3n) 288 115 (0.1 s) → 284 113 (0.5 s)

35. DRIBs-IIIDRIBs-III  Creation of the new experimental hall (≈ 2600 м 2 )  Creation of high current heavy ion accelerator  Development and creation of next generation set-ups 2010 -2016

37. Gas-Filled Separator Ready time must be synchronized with the construction of the new experimental hall & accelerator ADVANTAGES:  presence of a gas – H 2, He; high energy and charge acceptances; additional target cooling through convection;  low number of elements;  no high voltage.

38. NEW EXPERIMENTAL HALL

39. a)b) c)d) a). Cumulative alpha spectrum from 16 pairs of detectors b). Cumulative spectrum of fission fragments from 16 pairs of detectors c). Cumulative alpha spectrum from 8 th pair of detectors d). Cumulative spectrum of fission fragments from 8 th pair of detectors

40. a). Cumulative alpha spectrum from 16 pairs of detectors b). Cumulative spectrum of fission fragments from 16 pairs of detectors c). Cumulative alpha spectrum from 4 th pair of detectors d). Cumulative spectrum of fission fragments from 4 th pair of detectors a)b) c)d)

41. Chromatographic deposition of 209 At and 185 Hg in the detector array at 0°C together with a standard Monte-Carlo simulation of the 209 At deposition.

42. The deposition of 185 Hg compared to the deposition of 209 At in the isothermal detector array at 0°C together with Monte-Carlo simulation of the depositions. The Hg deposition points to an efficient chromatographic gold surface the second part of the experiment.

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