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Synthesis of the heaviest elements at RIKEN

Synthesis of the heaviest elements at RIKEN. Kosuke Morita Superheavy Element Laboratory RIKEN Nishina Center. Dr. Yoshio Nishina with his Cyclotron. 238 U(n, g ) 239 U(23.5m b -) 239 Np(2.3day b -) E. McMillan and P. H. Abelson Phys. Rev. 57 (1940)1185.

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Synthesis of the heaviest elements at RIKEN

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  1. Synthesis of the heaviest elements at RIKEN Kosuke Morita Superheavy Element Laboratory RIKEN Nishina Center Dr. Yoshio Nishina with his Cyclotron Periodic Table of D.I. Mendeleev. The new superheavy elements

  2. 238U(n,g)239U(23.5m b-) 239Np(2.3day b-) E. McMillan and P. H. Abelson Phys. Rev. 57(1940)1185 The first attempt to synthesize an artificial new element at RIKEN, Japan 238U(n,2n)237U(6.5day b-) Y. Nishina, T. Yasaki, H. Ezoe, K. Kimura, And M. Ikawa, Phys. Rev. 57(1940)1182 232Th(n,2n)231Th(25day b-) Y. Nishina, T. Yasaki, H. Ezoe, K. Kimura, And M. Ikawa, Nature, 142(1940)874 Periodic Table of D.I. Mendeleev. The new superheavy elements

  3. RARF: Riken Accelerator Research Facility est. since 1986 RIKEN GARIS 1987 - 1999 GARIS/IGiSOL RIPS Periodic Table of D.I. Mendeleev. The new superheavy elements

  4. RIKEN GARIS 2001 - 2009 Periodic Table of D.I. Mendeleev. The new superheavy elements

  5. Beam Energy Monitor GARIS RILAC Facility CSMAcc. Tanks RILAC Acc. Tanks RFQ-Linac 18GHz ECR Ion Source RIKEN GARIS 2001 - 2009 Periodic Table of D.I. Mendeleev. The new superheavy elements

  6. New Recoil Separator GARIS-II RIKEN GARIS 2009 - GARIS－II GARIS GARIS-II GARIS Periodic Table of D.I. Mendeleev. The new superheavy elements

  7. ion optics 20 15 Y[cm] 10 5 0 -5 -10 X [cm] -15 -20 0 1 2 3 4 5 6 Z [m] GARIS-II International School of Nuclear Physics at Erice

  8. RIKEN Gas-filled Recoil Separator GARIS beam Differential pumping section D1 Q1 Q2 D2 International School of Nuclear Physics at Erice

  9. PSD SSD box MCP2 ions MCP1 Focal Plane Detectors International School of Nuclear Physics at Erice

  10. 272Rg 14 chains 278113 271Ds 14 chains Reactions studied at RIKEN-GARIS 277112 2 chains 116 176 115 114 113 112 263, 264, 265Hs 111 Ds Mt 170 Hs Bh Sg 265Sg Db Rf 162 a 261Rf Lr SF No b+ or EC Md b- Fm Es New ! Cf 152 International School of Nuclear Physics at Erice

  11. Yield – Cross section (sensitivity) Y = s×T × B × e Y= 4×10-6 /s → 1 event/3days International School of Nuclear Physics at Erice

  12. International School of Nuclear Physics at Erice

  13. a a a a a a a a a a 208Pb(64Ni,n)271Ds CN 271Ds Eproj=313MeV 2.2 ms 10.73 MeV (PSD) 26-Jul-2002 Eproj=313MeV 267Hs 68.0 ms 9.82 MeV (PSD) 25-Sep-2002 263Sg CN 271Ds 18.0 ms 8.71 MeV (PSD+SSD) 239 ms 10.71 MeV (PSD+SSD) 259Rf 267Hs 3.13 s 8.87MeV (PSD) 66.0 ms 10.09 MeV (PSD+SSD) 255No 263Sg 394.7 s s 8.07 MeV (PSD) 48.0 ms 10.83 MeV (PSD+SSD) 251Fm 259Rf 2.71s 10.46 MeV (PSD+SSD) 255No 58.4 s 7.73 MeV (PSD) 251Fm

  14. 5 5 5 5 5 0 0 0 0 0 251Fm  255No  259Rf  263Sg  267Hs  271Ds a5 a4 a3 a2 a1 t=2.9ms t=120ms 5 a1 a1 0 11 5 1000s 1ms 0.1s 10s 8 9 t=77ms a2 a2 0 5 1000s 1ms 0.1s 10s 8 9 10 11 Counts/bin t=1.0s a3 a3 Counts/100keV 0 5 1000s 1ms 0.1s 10s 8 9 10 11 t=3.7s a4 a4 0 5 1000s 1ms 0.1s 10s 8 9 10 11 t=220s a5 a5 0 1000s 10ms 1ms 0.1s 10s 7 8 9 10 11 Tdecay (sec) Ea (MeV)

  15. 208Pb + 64Ni → 271Ds + n

  16. a a a a a a a a a a a 26-Feb-2003 CN 272111 1.42 ms 11.25 MeV (PSD) 209Bi(64Ni,n)272111 Eproj=323MeV 268Mt 36.6 ms 10.43 MeV (PSD+SSD) 26-Feb-2003 CN 272111 264Bh 4th 7.11 ms 10.82 MeV (PSD+SSD) 1.87 s 9.66 MeV (PSD+SSD) 268Mt 260Db 0.715 ms 10.28 MeV (PSD) 1.52 s 9.40 MeV (PSD) CN 272111 264Bh 256Lr 2.82 ms 11.31 MeV (LG) 0.54 s 9.57 MeV (PSD) 268Mt 260Db 44 ms 10.78 MeV (PSD+SSD) S.F. 264Bh 1.71 s 231 MeV (PSD+SSD) 0.44 s 9.58 MeV (PSD) 260Db 5th 48.46 s 8.81 MeV (PSD) 6th 256Lr 8-Apr-2003

  17. a a a a a a a a a a a a 14-Apr-2003 CN 272111 1.17 ms 10.58 MeV (LG) Eproj=323MeV 209Bi(64Ni,n)272111 268Mt 38.33 ms 10.35 MeV (PSD) 15-Apr-2003 CN 272111 264Bh 7th 8.89 ms 10.96 MeV (PSD+SSD) 3.6 ms 9.31 MeV (PSD) 268Mt 260Db 26.18 ms 2.76 MeV (PSD)esc 4.87 s 9.01 MeV (PSD) CN 272111 264Bh 256Lr 5.11 ms 11.06 MeV (PSD) S.F. 45.84 s 8.50 MeV (PSD) 268Mt 252Md 0.97 s 208 MeV (PSD) 19.1 ms 10.43 MeV (PSD) 264Bh 1.34 s 9.50 MeV (PSD) 8th 260Db 9th 3.69 s 9.10 MeV (PSD) 256Lr 7.87 s 8.41 MeV (PSD) 16-Apr-2003 252Md

  18. 5 5 a1 a1 0 0 5 5 a2 a2 0 0 Counts / 100 keV 5 5 a3 Counts / bin a3 0 0 5 5 a4 a4 0 0 5 5 a5 a5 0 0 8 9 10 11 12 100ms 10ms 1s 100s 10000s E / MeV Tdecay α 252Md ← 256Lr ← 260Db ← 264Bh ← 268Mt ← 272111 α３ α４ α２ α１ α５ t=5.5ms α１ α１ α２ t=30ms α２ t=1.3s α３ α３ α４ α４ t=27s t=2.2s α５ t=27s α５ (sec)

  19. Summary of 209Bi + 64Ni → 272111 + n

  20. Experimental condition 208Pb(70Zn, n)277112 period 2004/4/2 ～ 2004/5/24 Beam Energy 346 MeV at target half depth Total Dose 4.4x1018 Target Thickness 450 μg/cm2 number of events 2 s0.44+0.59-0.29 pb Irradiation time 693 Hours (28.9 Days) Beam Intensity 1.76x1012 /s (0.3 p-mA) Counting rate ～1 cps J. Phys. Soc. Jpn., Vol. 76, No. 4, p.043201(2007) International School of Nuclear Physics at Erice

  21. Observed events at RIKEN in 208Pb + 70Zn reaction Strip #8 Strip #11 34.42 MeV 23.33 mm 35.13 MeV 18.45 mm 277112 CN 277112 CN 16-April-2004 E (70Zn) = 349.5 MeV 11.09 ± 0.07 MeV 1.10 ms 23.57 mm 11.32 ± 0.04 MeV 1.22 ms 18.31 mm 273Ds 273Ds 11.14 ± 0.04 MeV 0.52 ms 23.45 mm 11.15±0.07MeV (2nd trig. PSD+SSD) 39.9 ms 20.18 mm 269Hs 269Hs 9.17 ± 0.04 MeV 14.19 s 23.34 mm 9.25 ± 0.07 MeV(PSD+SSD) 0.270 s 19.03 mm 265Sg 265Sg 8.71 ± 0.04 MeV 23.02 s 23.45 mm 8.70 ± 0.04 MeV 79.9 s 18.05 mm 261Rf 261Rf 22-May-2004 E (70Zn) = 349.5 MeV 197.3 MeV 2.97 s 23.41 mm 156.3 MeV 8.3 s 18.50 mm International School of Nuclear Physics at Erice

  22. 32.04 MeV 18.06 mm 277112 CN Observed events at GSI in 208Pb + 70Zn reaction 11.45 MeV 280 ms 17.85 mm 24.09 MeV 26.06 mm 273Ds 277112 CN 09-Feb-1996 E(70Zn) = 343.8 MeV 11.08 MeV 110 ms 17.77 mm 11.17 MeV 1406 ms 26.03 mm 269Hs 273Ds 9.23 MeV 19.7 s 17.81 mm 11.20 MeV 310 ms 26.01 mm 265Sg 269Hs 4.60 MeV 7.4 s 17.57 mm 9.18 MeV 22.0 s 26.16 mm 261Rf 265Sg 8.52 MeV 4.7 s 17.96 mm 0.2 MeV 18.8 s 27.33 mm 257No 261Rf 05-May-2000 E (70Zn) = 346.1 MeV 8.34 MeV 15.0 s 17.91 mm 153 MeV 14.5 s 26.70 mm 253Fm International School of Nuclear Physics at Erice

  23. International School of Nuclear Physics at Erice

  24. N=165 277112 t = 1.0 ms N=163 273Ds t = 0.24 ms RIKEN N=161 GSI 269Hs t = 14 s N=159 265Sg t = 32 s N=157 261Rf t = 7.6 s 10ms 1000s 1ms 0.1s 10s International School of Nuclear Physics at Erice T_decay/s

  25. t T1/2 277112 1.0 +1.0 ms 0.69 +0.69 ms -0.3 -0.23 273Ds 0.25 +0.25 ms 0.17 +0.17 ms -0.08 -0.06 269Hs 14 +14 s 9.7 +9.7 s -5 -3.2 265Sg 32 +32 s 22 +22 s -11 -8 261Rf 7.6 +7.6 s 5.3 +5.3 s -2.5 -1.8 International School of Nuclear Physics at Erice

  26. Summary of 209Bi + 70Zn experiment period 2003/9/5 ～ 2008/3/31 Beam Energy 5.03 AMeV 348 MeV at target half depth Total Dose 8.5x1019 Target Thickness 1.3x1018 /cm2 (0.45 mg/cm2) e_GARIS 0.8 s(2-ev.) 2.3x10-38 cm2 23 +30-15 fb Irradiation time 7477 Hours (312 Days) Beam Intensity 3.0x1012 /s (0.5 p-mA) J. Phys. Soc. Jpn., Vol. 73, No. 10,p.2593(2004) International School of Nuclear Physics at Erice

  27. 20 272Ds 10 273111 4 2 s (pb) 278112 1 0.5 279113 0.3 0.2 0.1 5 10 15 20 Ex of C.N. (MeV) Calculated threshold of fission after 1n emission Masses of Beams & Targets Audi & Wapstra, Nucl. Phys A565, 1 (1993) Masses of Compound Nuclei Myers & Swiatecki, Nucl. Phys. A601, 141 (1996) International School of Nuclear Physics at Erice

  28. Periodic Table of D.I. Mendeleev. The new superheavy elements

  29. 36.75 MeV TOF 44.61 ns 30.33 mm 36.47 MeV TOF 45.69 ns 30.08 mm 209Bi + 70Zn → 278113 + n 278113 CN 278113 CN 23-July-2004 18:55 (JST) a a 1st chain 11.68 MeV (PSD) 344μs 30.49 mm 11.52 MeV (PSD) 4.93ms 30.16 mm 1st chain 274111 274111 a a 11.15 MeV 6.149+5.003 (PSD+SSD) 9.260 ms 30.40 mm 0.88+10.43=11.31 MeV (PSD+SSD) 34.3 ms 29.61 mm 270Mt 270Mt a a 10.03 MeV 1.136+8.894(PSD+SSD) 7.163 ms 29.79 mm 2.32 MeV (escape) 1.63 s 29.45 mm 266Bh 266Bh s = 23 fb a a 2nd chain 9.08 MeV (PSD) 2.469 s 30.91 mm 9.77 MeV (PSD) 1.31 s 29.65 mm 2-April-2005 2:18 (JST) 262Db 262Db 204.05 MeV(PSD) 40.9 s 30.25 mm 192.32 MeV(PSD) 0.787 s 30.47 mm s.f. International School of Nuclear Physics at Erice s.f.

  30. N=165 278113 t = 2.6 ms N=163 274Rg t = 21.8 ms RIKEN N=161 270Mt t = 0.82 s N=159 266Bh t = 1.89 s N=157 262Db t = 20.8 s 10ms 1000s 1ms 0.1s 10s International School of Nuclear Physics at Erice T_decay/s

  31. Systematics by Viola & Seaborg a=1.81040, b=-21.7199, c=-0.26488, d=-28.1319 by Smolanczuk, Phys. Rev. C56(1997)812 1000 Rg Bh Mt 100 113 10 Hindrance Factor (Texp/Tcalc) 112 Ds Hs 1 Sg Rf 0.1 156 166 162 164 158 160 neutron number International School of Nuclear Physics at Erice

  32. 261Rfa 68 s 8.28 MeV 257No 25 s 8.22, 8.32 MeV 248Cm(18O,5n)261Rf α spectrum of MANON GARIS efficiency Dose: 6.3×1017 Chamber: 49 kPa He: 2 L/min KCl: 620 oC Coll. step: 30 s 7 up detectors No background peaks at > 8 MeV 161 α (58 α-α) / 8.2-h meas. Bρ = 1.75±0.02 Tm, ΔBρ/Bρ = 12.7±1.9% GARIS eff.: 7.8±1.7% for Φ100 mm (σ = 13 nb) Gas-jet eff.: 52±12% Periodic Table of D.I. Mendeleev. The new superheavy elements

  33. 265Sg 9 s 16 s 8.85 8.69 261Rf 68 s 3 s 8.28 8.51, SF 257No 25 s 8.22, 8.32 248Cm(22Ne,5n)265Sg 1 chain 8 chains 4 chains 1 chain 265Sgb 265Sga 3.2 s 265Sgb 24 s 265Sgb 56.2 s 8.80 33.5 s 8.69 8.85 8.66 Preliminary 261Rfb 261Rfa 48 s 261Rfb 1.5 s 261Rfa 15.9 s 8.57 18.3 s 8.38 8.31 257No 257No 14 s 257No 32.2 s 8.18 17.2 s 8.29 8.27 Düllmann and Tüler: PRC 77, 064320 (2008). 14 correlations(35 α/fission events) on 265Sg, 261Rf, and 257No Bρ = 2.07±0.01 Tm, ΔBρ/Bρ = 8.4±1.1% Periodic Table of D.I. Mendeleev. The new superheavy elements

  34. Summary I • 208Pb(58Fe,n)265Hs, 208Pb(64Ni,n)271Ds,209BiPb(64Ni,n)272Rg, 208Pb(70Zn,n)277112, and 209Bi(70Zn,n)278113 reactions have been studied. • Independent confirmations of synthesis of elements 108, 110, 111, and 112 • Optimum reaction energies for (HI,n) reactions were studied • New synthesis of an isotope of 113th element International School of Nuclear Physics at Erice

  35. Summary II • 278113 was produced by 209Bi(70Zn,n) reaction. • 278113(a)→274Rg(a)→270Mt(a)→266Bh(a)→262Db(SF) • Identification was based on • connected to the known decays 266Bh(a)→262Db(SF) • reaction energy systematics • cross section systematics • Z & A of 278113 are largest ones among the isotopes produced by cold fusion reaction. International School of Nuclear Physics at Erice

  36. Summary III (preliminary) • 264Hs(108) was produced by 207Pb(58Fe,n) and 208Pb(58Fe,2n) reaction. • confirmation, spectroscopic information of even-even nucleus. • 263Hs(108) was produced and identified by 206Pb(58Fe,n), and reaction208Pb(56Fe,n). • new isotope • Off line experiment for the chemistry of superheavy element coupled to a Recoil Separator using hot fusion reactions started. International School of Nuclear Physics at Erice

  37. International School of Nuclear Physics at Erice

  38. Future Plan Facility & Device After the installation of the New Injector for SRC, existing Linac will be used mostly for the Superheavy research. We will have two recoil ion separators for the Superheavy research. Beam time for Superheavy research will increase much. We should try to utilize fully this situation as efficient as possible. We will consider to open our RILAC + GARIS facility to users worldwide both Chemists and Physicists near in future. We could show the intensities of certain isotopes of heavy elements to users within a few years. Periodic Table of D.I. Mendeleev. The new superheavy elements

  39. Thank you for your attention. International School of Nuclear Physics at Erice

  40. Periodic Table of D.I. Mendeleev. The new superheavy elements

  41. 248Cm Target 50,000,000 JPY International School of Nuclear Physics at Erice

  42. ・Research in future ーScience of heavy elementsー 1)Searching for new elements 2)Spectroscopic study of heaviest elements 3)Chemistry of heaviest elements 4)Development of the new detectors for SHE study International School of Nuclear Physics at Erice

  43. 7477/312 2 events Total Z=113 Z=112 International School of Nuclear Physics at Erice

  44. Excitation function of208Pb(64Ni,n)271Ds 208Pb + 64Ni → 271Ds + n RIKEN errors GSI statistical (1s) s (pb) energy loss in the target E(64Ni) /MeV (lab.)

  45. 5 5 a1 0 0 5 5 a2 0 0 Counts / 100 keV 5 5 Counts / bin a3 0 0 5 5 a4 a4 0 0 5 5 a5 a5 0 0 8 9 10 11 12 100ms 10ms 1s 100s 10000s E / MeV Tdecay α 252Md ← 256Lr ← 260Db ← 264Bh ← 268Mt ← 272111 α３ α５ α４ α２ α１ t=5.5ms α１ α１ α２ t=30ms α２ t=1.3s α３ α３ α４ α４ t=27s t=2.2s α５ t=27s α５ (sec) International School of Nuclear Physics at Erice Journal of Physical Society of Japan (JPSJ) Vol. 73, (2004) 1738 - 1744

  46. Excitation function of 209Bi(64Ni,n)272111

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