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Chemistry of Spherical Superheavy Elements – The Road to Success

Chemistry of Spherical Superheavy Elements – The Road to Success. island of spherical SHE. 114. peak of Th,U. peak of Pb. 82. strait of radioactivity. Number of protons. sea of instability. 50. peak of Sn. 20. sea of instability. peak of Ca. 82. 126. 184. 20. Number of neutrons.

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Chemistry of Spherical Superheavy Elements – The Road to Success

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  1. Chemistry of Spherical Superheavy Elements – The Road to Success

  2. island of spherical SHE 114 peak of Th,U peak of Pb 82 strait of radioactivity Number of protons sea of instability 50 peak of Sn 20 sea of instability peak of Ca 82 126 184 20 Number of neutrons S. Soverna January 2004 IMP

  3. Evidence for long-lived isotopes from 48Ca induced fusion reactions on actinide targets (FLNR, published and unpublished data) 118 290 294 116 118 118  30 ms  2 ms a a/sf 116 292 116 116 » 53ms a 115 287 288 115 115 115 »32 ms »87 ms a a 114 289 286 287 288 114 114 114 114 114  0.4 s »5 s »2.6 s »20 s a a a a 113 284 283 113 113 113 »0.48 s »100ms a a 283 284 285 112 112 112  3 min »45 s »10 min a a sf 279 280 111 111 174 »170ms »3.6 s a a 280 281 Ds Ds »7.6 s »1 min sf a 272 276 271 275 Mt Bh Mt Bh 172 170 »9.8 s »0.72 s »9.7 ms a a a a 277 267 266 270 269 Hs Hs Hs Hs Hs »10min 59 ms 2.3 ms 3.6 s  9.3 s sf a a 264 Bh 168 440 ms a 262 258 Sg Sg 6.9 ms 2.9 ms sf sf 267 268 Db Db • 73 m • 16 h 259 Db a a 0.5 s ,ec/sf? 112 277 112 Z 112 194ms 277ms a a 111 272 111 111 1.6 ms a 269 270 271 273 267 Ds Ds Ds Ds Ds Ds 110  3 s 170 m s 0.1ms 6 ms 1.1ms 56 ms 291 s Darmstadtium a a a a a a a a Mt 266 268 Mt Mt 109 1.7 ms 70 ms Meitnerium a a Hs 263 264 265 Hs Hs Hs 108 ? 0.45 ms 0.8ms 1.7ms Hassium a ,sf a a a a a a Bh 267 266 262 260 261 Bh Bh Bh Bh Bh 107 » 17 s » 1s ? 11.8 ms 102ms 8ms Bohrium a a a a a a Sg 261 265 259 260 263 266 Sg Sg Sg Sg Sg Sg 106 164 166 0.48 s 7.4 s 21 s 3.6 ms 0.23 s 1.4s 0.9s 0.3s Seaborgium a ,sf a ,ec a a ,sf? a a ,sf? a ,sf? Db 262 255 256 258 260 263 257 261 Db Db Db Db Db Db Db Db 105 160 1.6 s 2.6 s 1.3 s 4.4 s 1.5 s 1.8 s 34 s 27 s Dubnium a a ,sf a ,sf a ,sf a ,ec a ,ec/sf? a ,sf a ,ec/sf? a ,sf Rf 253 254 255 256 257 258 259 260 261 262 Rf Rf Rf Rf Rf Rf Rf Rf Rf Rf 47ms 7.9 s 48 m s 23 m s 6.2 m s 13 ms 3.1 s 21 ms 78 s 0.8s 1.4s 1.4s 4.7s 2.1s Ruther- fordium a a ,sf a ,sf sf, a a ,ec a ,ec , sf sf sf sf sf sf a ,sf sf a 150 152 154 156 158 N a-Decay Spontaneous fission EC-Decay

  4. Half-lives of primary evaporation residues and their progenies: ms to h(Chemistry needs ≥ s) • Decay properties: mostly a-decay chains ending in a SF-nuclide(Problem: No link to known nuclides) • Maximum production cross sections  1 to 5 pb (3n and 4n channels). For 1 mg/cm2 targets and 0.5 pmA beam approx. 0.6 to 3 atoms/day produced(Problem: UNILAC duty cycle, cw beam would enable approx. factor of 3higher intensity at equal peak current)

  5. The missing link: 118 290 294 116 118 118  30 ms  2 ms a a/sf 116 292 116 116 » 53ms a 115 287 288 115 115 115 »32 ms »87 ms a a 114 289 286 287 288 114 114 114 114 114  0.4 s »5 s »2.6 s »20 s a a a a 113 284 283 113 113 113 »0.48 s »100ms a a 283 284 285 112 112 112  3 min »45 s »10 min a a sf 279 280 111 111 174 »170ms »3.6 s a a 280 281 Ds Ds »7.6 s »1 min sf a 271 272 275 276 Bh Mt Mt Bh 172 170 »0.72 s »9.8 s »9.7 ms a a a a 277 266 267 270 269 Hs Hs Hs Hs Hs »10min 2.3 ms 59 ms  9.3 s 3.6 s sf a a 264 Bh 168 440 ms a 262 258 Sg Sg 2.9 ms 6.9 ms sf sf 267 268 Db Db • 73 m • 16 h 259 Db a a 0.5 s ,ec/sf? Hs chemistry, a tool to bridge the gap 112 277 112 Z 112 194ms 277ms a a 111 272 111 111 1.6 ms a 269 270 271 273 267 Ds Ds Ds Ds Ds Ds 110  3 s 170 m s 0.1ms 6 ms 1.1ms 56 ms 291 s Darmstadtium a a a a a a a Mt 266 268 Mt Mt 109 1.7 ms 70 ms Meitnerium a a Hs 263 264 265 Hs Hs Hs 108 ? 0.45 ms 0.8ms 1.7ms Hassium a ,sf a a a a a a Bh 267 266 262 260 261 Bh Bh Bh Bh Bh 107 » 17 s » 1s ? 11.8 ms 102ms 8ms Bohrium a a a a a a Sg 261 265 259 260 263 266 Sg Sg Sg Sg Sg Sg 106 164 166 0.48 s 7.4 s 21 s 3.6 ms 0.23 s 1.4s 0.9s 0.3s Seaborgium a ,sf a ,ec a a ,sf? a a ,sf? a ,sf? Db 262 255 256 258 260 263 257 261 Db Db Db Db Db Db Db Db 105 160 1.6 s 2.6 s 1.3 s 4.4 s 1.5 s 1.8 s 34 s 27 s Dubnium N a a ,sf a ,sf a ,sf a ,ec a ,ec/sf? a ,sf a ,ec/sf? a ,sf Rf 253 254 255 256 257 258 259 260 261 262 Rf Rf Rf Rf Rf Rf Rf Rf Rf Rf 47ms 7.9 s 48 m s 23 m s 6.2 m s 13 ms 3.1 s 21 ms 78 s 0.8s 1.4s 1.4s 4.7s 2.1s Ruther- fordium a-Decay Spontaneous fission EC-Decay a a ,sf a ,sf sf, a a ,ec a ,ec , sf sf sf sf sf sf a ,sf sf a A. Türler et al.

  6. Half-lives of primary evaporation residues and their progenies: ms to h(Chemistry needs ≥ s) • Decay properties: mostly a-decay chains ending in a SF-nuclide(Problem: No link to known nuclides) • Maximum production cross sections  1 to 5 pb (3n and 4n channels). For 1 mg/cm2 targets and 0.5 pmA beam approx. 0.6 to 3 atoms/day produced(Problem: UNILAC duty cycle, cw beam would enable approx. factor of 3higher intensity at equal peak current)

  7. S. Soverna January 2004 IMP Periodic table of the elements

  8. 120 100 Standardenthalpiesof gaseousmono-atomic elements 80 DH°298 [kcal/mol] 60 40 20 0 100 120 60 80 40 20 0 Atomic number Extrapolation of the standard enthalpies for SHE B. Eichler, 1976 Conclusion: Elements 112 to 117 should be volatile noble metal-like elementsProblem: Influence of relativistic effects?

  9. Predictions for element 112 Extrapolations Relativistic B. Eichler,Kernenergie 10, 307 (1976 ) B. Eichler,PSI Report 03-01, Villigen (2000) V. Pershina et al.,Chem. Phys. Lett., 365, 176 (2002) K.S. Pitzer,J. Chem. Phys. 63, 1032 (1975) Noble gas like Volatile metal

  10. How to experimentally determine a metallic character at a single atom level? → Determine interaction energy (adsorption enthalpy) with (noble*) metals, i.e. measure retention temperature * Easier to keep clean surface during experiment

  11. Gas flow isothermalchromatography Gas flow T 50% Yield [%] tRet. = T1/2 Temperature [°C] Temperature [°C] low high Column length [cm] thermochromatography T a Temperature [°C] Yield [%] Column length [cm] Temperature [°C] high low

  12. (Au) D Correlation of H with H D subl ads R. Eichler et al.

  13. Current interest: element 112 → Behaves E112 similar to Hg ? → Production: 238U(48Ca;3n)283112 (SF;T1/2 3 min) → 2 chemistry experiments performed with evicence for: At FLNR: Isothermal chromatography on Au: E112 does not adsorb at room temp. DHa< 60 kJ/mol (A. Yakushev et al.) At GSI: Thermochromatography: E112 does not deposit on Au down to -90 °C DHa< 48 kJ/mol (S. Soverna et al.)

  14. 238U(48Ca,3n)283112 283 286 283 286 112 112 EVR 112 112 EVR » 20 s » 20 s » 20 s » 20 s 0.9 m 3 m 8.7-8.9 8.7-8.9 8.7-8.9 8.7-8.9 sf sf 283 286 283 286 112 112 EVR 112 112 EVR » 20 s » 20 s » 20 s » 20 s 24.3 m 3 m 8.7-8.9 8.7-8.9 8.7-8.9 8.7-8.9 sf sf VASSILISSA E* 33 MeV E* 35 MeV Oganessian et al., 1999 & in press

  15. Current interest: element 112 → Behaves E112 similar to Hg ? → Production: 238U(48Ca;3n)283112 (SF;T1/2 3 min) → 2 chemistry experiments performed with evicence for: At FLNR: Isothermal chromatography on Au: E112 does not adsorb at room temp. DHa< 60 kJ/mol (A. Yakushev et al.) At GSI: Thermochromatography: E112 does not deposit on Au down to -90 °C DHa< 48 kJ/mol (S. Soverna et al.)

  16. Chemical isolation of Element 112 Beam: 48Ca (262 MeV) 0.6 pA Ar +CH4 mixture 48Ca Gas outlet He Target: U3O8- 2mg/cm2 + Nd2O3 - 50 g/cm2 Dose: 2.8x1018; 8 SF detected in ion.chamber in coincidence with 1 to 3 neutrons He outlet He inlet

  17. Current interest: element 112 → Behaves E112 similar to Hg ? → Production: 238U(48Ca;3n)283112 (SF;T1/2 3 min) → 2 chemistry experiments performed with evicence for: At FLNR: Isothermal chromatography on Au: E112 does not adsorb at room temp. DHa< 60 kJ/mol (A. Yakushev et al.) At GSI: Thermochromatography: E112 does not deposit on Au down to -90 °C DHa< 48 kJ/mol (S. Soverna et al.)

  18. 48Ca-Beam rotating 238U-target (1.6 mg cm-2) ~10 m PFA-capillary oven(850 °C) He (dried) COLD quartz wool filter recoil chamber +35 °C to -185 °C thermostat N2 (liq.) (-196 °C) oven (1000 °C) (+35 °C) Ta-/Ti-getter PIN-dioden oppositer surface a Au S. Soverna January 2004 IMP IVO set-up (experiment at GSI in Feb. & Mar. 2003)

  19. Experiment GSI February-March 2003 238U(48Ca, 3n)283112 (SF, 3min) 283112

  20. Both experiments not conclusive, because → Detection of SF activity not specific to assign it to a given (isotope of an) element. → Fission fragment energies too low (FLNR: ion. chamber; GSI: PIN- diodes)

  21. Current effort: focus on a-decaying nuclides

  22. 48Ca + 238U @ DGFRS/FLNR V. Utyonkov, priv. comm. Feb. 2004

  23. Rn Trap Device 2004 Ar/He carrier gas loop (v=10 l) Recoil chamber (volume approx.10 cc 48Ca beam Getter oven 4-p COLD, 1 side gold Pressure gauge / MFC Buffer Ar - refill Mass flow controller All metal

  24. Requirements for future SHE chemistry experiments (e.g. Z=114) • Fast (separation time approx. 1 s) • Separation of transfer products prior to chemistry set-up: ChemSep • Chemistry behind a ChemSep • Beam dose of ≥ 1019 required for approx. 1 month experiments: 1 pmA average beam intensity! cw-LINAC; Novel target technology (stable compounds, liquid metal targets)

  25. 242Pu(48Ca,3n)287114 244Pu(48Ca,5n)287114 293 116 EVR » 20 s 16 x 1 x 1 x 8.7-8.9 290 287 290 114 EVR 114 114 EVR » 20 s » 20 s » 20 s 1 s 8.7-8.9 8.7-8.9 8.7-8.9 a 10 E* 32-52 MeV E* 40 MeV E* 52 MeV 283 112 283 112 283 » 20 s 112 » 20 s 7.8 s 4 s 8.7-8.9 8.7-8.9 a 9.5 » 20 s a 9.5 8.57 s 8.7-8.9 a 9.5 2 x 179 179 Ds Ds 179 Ds 0.28 s 0.2 s sf 0.2 s a 9.7 sf 290 114 EVR » 20 s 275 Hs 8.7-8.9 » 20 s 422 ms 8.7-8.9 a 9.3 E* 35 MeV 271 287 283 287 291 287 Sg 116 114 114 112 114 245Cm(48Ca,2n)291116 » 20 s » 20 s » 20 s » 20 s » 20 s » 20 s 6.3 m 8 ms 1 s 1 s 5.4 s 1.5 s 8.7-8.9 8.7-8.9 8.7-8.9 8.7-8.9 8.7-8.9 8.7-8.9 sf a 9.5 a 10.75 a 10 a 10 a 10 179 Ds 0.31 s sf DGFRS

  26. Reqiurements for future SHE chemistry experiments • Fast (separation time approx. 1 s) • Separation of transfer products prior to chemistry set-up: ChemSep • Chemistry behind a ChemSep • Beam dose of ≥ 1019 required for approx. 1 month experiments: 1 pmA average beam intensity! cw-LINAC; Novel target technology (stable compounds, liquid metal targets)

  27. Transfer reaction products! H.W. Gäggeler et al., Phys. Rev. C33, 1983 (1986) 48Ca + 248Cm 220Rn

  28. Requirements for future SHE chemistry experiments • Fast (separation time approx. 1 s) • Separation of transfer products prior to chemistry set-up: ChemSep • Chemistry behind a ChemSep • Beam dose of ≥ 1019 required for approx. 1 month experiments: 1 pmA average beam intensity! cw-LINAC; • Novel target technology (stable compounds, liquid metal targets)

  29. A recoil/gas chemistry chamber at the Berkeley Gas-filled Separator (BGS)

  30. Hot-catcher coupled to vacuum thermochromatography set-up Hot Catcher Induction heating R. Eichler, Qin Zhi . SHE@CHEMSEP

  31. R.Eichler, Qin Zhi

  32. Requirements for future SHE chemistry experiments • Fast (separation time approx. 1 s) • Separation of transfer products prior to chemistry set-up: ChemSep • Chemistry behind a ChemSep • Novel target technology (stable compounds, liquid metal targets) • Beam dose of ≥ 1019 required for approx. 1 month experiments: 1 pmA average beam intensity! cw-LINAC;

  33. Suggested application: liquid U/Mn (80/20) at 700 °C

  34. Requirements for future SHE chemistry experiments • Fast (separation time approx. 1 s) • Separation of transfer products prior to chemistry set-up: ChemSep • Chemistry behind a ChemSep • Novel target technology (stable compounds, liquid metal targets) • Beam dose of ≥ 1019 required for approx. 1 month experiments: 1 pmA average beam intensity! (cw-LINAC)

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