Slide 1

Synthesis of the heaviest elements at RIKEN Kosuke Morita Superheavy Element Laboratory RIKEN Nishina Center 2009/1/201Periodic Table of D.I. Mendeleev. The new superheavy elements Dr. Yoshio Nishina with his Cyclotron Slide 2 2009/1/20Periodic Table of D.I. Mendeleev. The new superheavy elements 2 238 U(n,2n) 237 U(6.5day -) Y. Nishina, T. Yasaki, H. Ezoe, K. Kimura, And M. Ikawa, Phys. Rev. 57(1940)1182 238 U(n, ) 239 U(23.5m -) 239 Np(2.3day -) E. McMillan and P. H. Abelson Phys. Rev. 57(1940)1185 The first attempt to synthesize an artificial new element at RIKEN, Japan 232 Th(n,2n) 231 Th(25day -) Y. Nishina, T. Yasaki, H. Ezoe, K. Kimura, And M. Ikawa, Nature, 142(1940)874 Slide 3 2009/1/20Periodic Table of D.I. Mendeleev. The new superheavy elements 3 RIKEN GARIS 1987 - 1999 RIPS RARF: Riken Accelerator Research Facility est. since 1986 GARIS/IGiSOL Slide 4 2009/1/20Periodic Table of D.I. Mendeleev. The new superheavy elements 4 RIKEN GARIS 2001 - 2009 Slide 5 2009/1/20Periodic Table of D.I. Mendeleev. The new superheavy elements 5 RILAC Facility 18GHz ECR Ion Source RFQ-Linac CSM Acc. Tanks RILAC Acc. Tanks GARIS Beam Energy Monitor RIKEN GARIS 2001 - 2009 Slide 6 2009/1/20Periodic Table of D.I. Mendeleev. The new superheavy elements 6 New Recoil Separator GARIS-II GARIS GARIS-II RIKEN GARIS 2009 - GARIS GARIS II Slide 7 2008/9/17International School of Nuclear Physics at Erice 7 ion optics GARIS-II Slide 8 2008/9/17International School of Nuclear Physics at Erice 8 beam Differential pumping section D1 Bending angle45 degree Pole gap150 mm Radius of central ray1200 mm Maximum field1.54 T Q1, Q2 Pole length500 mm Bore radius150 mm Maximum field gradient5.2 T/m D2 Bending angle10 degree Pole gap160 mm Pole length400 mm Maximum Field1.04 T MagnificationX-0.76 Y-1.99 Dispersion0.97 cm/% Total length5760 mm Acceptance 68 mrad 57 mrad 12.2 msr Rotating Target r150 mm 2000 rpm RIKEN Gas-filled Recoil Separator GARIS D1 Q1 Q2 D2 Slide 9 2008/9/17International School of Nuclear Physics at Erice 9 MCP1 MCP2 SSD box PSD ions Focal Plane Detectors Slide 10 2008/9/17International School of Nuclear Physics at Erice 10 116 115 114 113 112 111 Ds Mt Hs Bh Sg Db Rf Lr No Md Es Cf Fm 162 152 SF + or EC -- 170 176 Reactions studied at RIKEN-GARIS 271 Ds 14 chains 272 Rg 14 chains 278 113 New ! 208 Pb( 58 Fe, n) 265 Hs 208 Pb( 64 Ni, n) 271 Ds 209 Bi( 64 Ni, n) 272 Rg 208 Pb( 70 Zn, n) 277 112 209 Bi( 70 Zn, n) 278 113 207 Pb( 58 Fe, n) 264 Hs 206 Pb( 58 Fe, n) 263 Hs 208 Pb( 56 Fe, n) 263 Hs 208 Pb( 58 Fe, 2n) 264 Hs 248 Cm( 18 O,5n) 261 Rf 248 Cm( 22 Ne,5n) 265 Sg 248 Cm( 23 Na,5n) 266 Bh 261 Rf 263, 264, 265 Hs 265 Sg 277 112 2 chains Slide 11 2008/9/17International School of Nuclear Physics at Erice 11 Yield Cross section (sensitivity) Y = T B typical value Yevent rate/s cross sectioncm 2 10 -36 1 p-barn Ttarget thickness/cm 2 1.310 18 450 g/cm 2 Bbeam intensity/s410 12 0.65 particle A efficiency0.8 Y= 410 -6 /s 1 event/3days Slide 12 2008/9/17International School of Nuclear Physics at Erice 12 Slide 13 CN 271 Ds 267 Hs 255 No 259 Rf 263 Sg 251 Fm 25-Sep-2002 239 ms 10.71 MeV (PSD+SSD) 66.0 ms 10.09 MeV (PSD+SSD) 48.0 ms 10.83 MeV (PSD+SSD) 2.71s 10.46 MeV (PSD+SSD) 58.4 s 7.73 MeV (PSD) E proj =313MeV 26-Jul-2002 CN 271 Ds 267 Hs 255 No 259 Rf 263 Sg 2.2 ms 10.73 MeV (PSD) 68.0 ms 9.82 MeV (PSD) 18.0 ms 8.71 MeV (PSD+SSD) 3.13 s 8.87MeV (PSD) 208 Pb( 64 Ni,n) 271 Ds 251 Fm 394.7 s s 8.07 MeV (PSD) E proj =313MeV Slide 14 11 10 9 9 9 9 98 8 8 7 11 22 33 44 55 11 10 8 8 E (MeV) 5 0 5 0 5 0 5 0 5 0 Counts/100keV 11 22 33 44 55 Tdecay (sec) Counts/bin 0 1000s 10s0.1s1ms 5 0 5 1000s 10s0.1s1ms 1000s 10s0.1s1ms 1000s 10s0.1s1ms 1000s 10s0.1s1ms 5 0 5 0 5 0 10 s =2.9ms =120ms =77ms =1.0s =3.7s =220s 251 Fm 255 No 259 Rf 263 Sg 267 Hs 271 Ds 11 22 33 44 55 Slide 15 NucleinT 1/2 271 Ds111.63 +0.44 -0.29 msimproved 271m Ds369 +56 -21 msconfirmed 267 Hs1252 +13 - 8 msimproved 267m Hs10.80 +3.8 -0.38 spossible Eopt(lab.)=314MeV Eopt(cm)=240MeV 208 Pb + 64 Ni 271 Ds + n Slide 16 CN 272 111 268 Mt 260 Db 264 Bh 26-Feb-2003 7.11 ms 10.82 MeV (PSD+SSD) 0.715 ms 10.28 MeV (PSD) 0.54 s 9.57 MeV (PSD) 1.71 s 231 MeV (PSD+SSD) E proj =323 MeV CN 272 111 268 Mt 256 Lr 260 Db 264 Bh 26-Feb-2003 1.42 ms 11.25 MeV (PSD) 36.6 ms 10.43 MeV (PSD+SSD) 1.87 s 9.66 MeV (PSD+SSD) 1.52 s 9.40 MeV (PSD) 2.82 ms 11.31 MeV (LG) CN 272 111 268 Mt 256 Lr 260 Db 264 Bh 8-Apr-2003 44 ms 10.78 MeV (PSD+SSD) 0.44 s 9.58 MeV (PSD) 48.46 s 8.81 MeV (PSD) 209 Bi( 64 Ni,n) 272 111 S.F. 6th 5th 4th Slide 17 CN 272 111 268 Mt 264 Bh 15-Apr-2003 8.89 ms 10.96 MeV (PSD+SSD) 26.18 ms 2.76 MeV (PSD)esc 0.97 s 208 MeV (PSD) E proj =323MeV CN 272 111 268 Mt 256 Lr 260 Db 264 Bh 252 Md 14-Apr-2003 1.17 ms 10.58 MeV (LG) 38.33 ms 10.35 MeV (PSD) 3.6 ms 9.31 MeV (PSD) 4.87 s 9.01 MeV (PSD) 45.84 s 8.50 MeV (PSD) 5.11 ms 11.06 MeV (PSD) CN 272 111 268 Mt 256 Lr 260 Db 264 Bh 252 Md 16-Apr-2003 19.1 ms 10.43 MeV (PSD) 1.34 s 9.50 MeV (PSD) 3.69 s 9.10 MeV (PSD) 7.87 s 8.41 MeV (PSD) 209 Bi( 64 Ni,n) 272 111 S.F. 9th 8th 7th Slide 18 =27s 252 Md 256 Lr 260 Db 264 Bh 268 Mt 272 111 =5.5ms =30ms =1.3s =2.2s =27s (sec) Slide 19 NucleinT 1/2 EE E fiss. MeV 272 111143.8 +1.4 - 0.8 ms10.2~11.56 268 Mt1421 +8 - 5 ms9.4~10.77 264 Bh140.89 +0.31 - 0.19 s8.86~9.83 208 206 260 Db125.7 +2.3 - 1.3 s8.35~9.4231 256 Lr818 +10 - 5 s8.35~8.65 Eopt(lab.)=319MeV Eopt(cm)=244MeV Summary of 209 Bi + 64 Ni 272 111 + n Slide 20 2008/9/17International School of Nuclear Physics at Erice 20 period2004/4/2 2004/5/24 Beam Energy346 MeV at target half depth Total Dose4.4x10 18 Target Thickness450 g/cm 2 number of events2 0.44 +0.59 -0.29 pb Irradiation time693 Hours(28.9 Days) Beam Intensity1.76x10 12 /s(0.3 p- A) Counting rate 1 cps Experimental condition 208 Pb( 70 Zn, n) 277 112 J. Phys. Soc. Jpn., Vol. 76, No. 4, p.043201(2007) Slide 21 2008/9/17International School of Nuclear Physics at Erice 21 277 112 273 Ds 269 Hs 265 Sg 261 Rf CN 11.09 0.07 MeV 1.10 ms 23.57 mm 11.14 0.04 MeV 0.52 ms 23.45 mm 9.17 0.04 MeV 14.19 s 23.34 mm 8.71 0.04 MeV 23.02 s 23.45 mm 197.3 MeV 2.97 s 23.41 mm 34.42 MeV 23.33 mm 16-April-2004 E ( 70 Zn) = 349.5 MeV Observed events at RIKEN in 208 Pb + 70 Zn reaction 277 112 273 Ds 269 Hs 265 Sg 261 Rf CN 11.32 0.04 MeV 1.22 ms 18.31 mm 11.150.07MeV (2 nd trig. PSD+SSD) 39.9 s 20.18 mm 9.25 0.07 MeV(PSD+SSD) 0.270 s 19.03 mm 8.70 0.04 MeV 79.9 s 18.05 mm 156.3 MeV 8.3 s 18.50 mm 35.13 MeV 18.45 mm 22-May-2004 E ( 70 Zn) = 349.5 MeV Strip #8Strip #11 Slide 22 2008/9/17International School of Nuclear Physics at Erice 22 277 112 273 Ds 269 Hs 265 Sg 261 Rf 257 No 253 Fm CN 11.45 MeV 280 s 17.85 mm 11.08 MeV 110 s 17.77 mm 9.23 MeV 19.7 s 17.81 mm 4.60 MeV 7.4 s 17.57 mm 8.52 MeV 4.7 s 17.96 mm 8.34 MeV 15.0 s 17.91 mm 32.04 MeV 18.06 mm 277 112 273 Ds 269 Hs 265 Sg 261 Rf CN 11.17 MeV 1406 s 26.03 mm 11.20 MeV 310 s 26.01 mm 9.18 MeV 22.0 s 26.16 mm 0.2 MeV 18.8 s 27.33 mm 153 MeV 14.5 s 26.70 mm 24.09 MeV 26.06 mm 09-Feb-1996 E( 70 Zn) = 343.8 MeV 05-May-2000 E ( 70 Zn) = 346.1 MeV Observed events at GSI in 208 Pb + 70 Zn reaction Slide 23 2008/9/17International School of Nuclear Physics at Erice 23 ref. 1Hofmann S. et al., Z. Phys. A354, 229 (1996) 208 Pb + 70 Zn 277 112 + n 2Hofmann S. and M nzenberg G., Rev. Mod. Phys. 72, 733 (2000) 208 Pb + 70 Zn 277 112 + n 3present 208 Pb + 70 Zn 277 112 + n 4present 208 Pb + 70 Zn 277 112 + n 5Lazarev Yu. A. et al., Phys. Rev. C54, 620 (1996) 244 Pu + 34 S 273 Ds + 5n 6Lazarev Yu. A. et al., Phys. Rev. C62, 064307(2000) 244 Pu + 22 Ne 261 Rf + 5n GSIRIKENFLNR ref.123456 277 11211.4511.1711.09.0711.32.04 0.28 ms1.41 ms1.10 ms1.22 ms 273 Ds11.0811.2011.14.0411.15.0711.35 0.11 ms0.31 ms0.52 ms0.04 ms0.39 ms 269 Hs9.239.189.17.049.25.07 19.7 s22.0 s14.2 s0.27 s 265 Sg4.600.208.71.048.70.048.63 74.0 s18.8 s23.0 s79.9 s158 s 261 Rf8.521531971568.300.06 4.70 s14.5 s2.97 s8.30 s54 +8 -4 s 257 No8.348.228.24, 8.34 15.0 s384 s17 s Slide 24 2008/9/17International School of Nuclear Physics at Erice 24 10 s 1ms 0.1s 10s 1000s 277 112 = 1.0 ms 273 Ds = 0.24 ms 269 Hs = 14 s 265 Sg = 32 s 261 Rf = 7.6 s T_decay/s RIKEN GSI N=165 N=163 N=161 N=159 N=157 Slide 25 2008/9/17International School of Nuclear Physics at Erice 25 0.25 14 1.0 32 7.6 277 112 273 Ds 269 Hs 265 Sg 261 Rf ms +0.25 -0.08 s +14 -5 ms +1.0 -0.3 s +32 -11 s +7.6 -2.5 0.69ms +0.69 -0.23 9.7s +9.7 -3.2 0.17ms +0.17 -0.06 22s +22 -8 5.3s +5.3 -1.8 T 1/2 Slide 26 2008/9/17International School of Nuclear Physics at Erice 26 period2003/9/5 2008/3/31 Beam Energy5.03 AMeV 348 MeV at target half depth Total Dose8.5x10 19 Target Thickness1.3x10 18 /cm 2 (0.45 mg/cm 2 ) _GARIS0.8 (2-ev.)2.3x10 -38 cm 2 23 +30 -15 fb Irradiation time7477 Hours(312 Days) Beam Intensity3.0x10 12 /s(0.5 p- A) Summary of 209 Bi + 70 Zn experiment J. Phys. Soc. Jpn., Vol. 73, No. 10, p.2593(2004 ) Slide 27 2008/9/17International School of Nuclear Physics at Erice 27 Masses of Beams & Targets Audi & Wapstra, Nucl. Phys A565, 1 (1993) Masses of Compound Nuclei Myers & Swiatecki, Nucl. Phys. A601, 141 (1996) Calculated threshold of fission after 1n emission 5 10 15 20 Ex of C.N. (MeV) 20 10 4 2 1 0.5 0.3 0.2 0.1 (pb) 272 Ds 273 111 278 112 279 113 Slide 28 2009/1/20Periodic Table of D.I. Mendeleev. The new superheavy elements 28 Slide 29 2008/9/17International School of Nuclear Physics at Erice 29 278 113 274 111 270 Mt 266 Bh CN 11.68 MeV (PSD) 344 s 30.49 mm 11.15 MeV 6.149+5.003 (PSD+SSD) 9.260 ms 30.40 mm 10.03 MeV 1.136+8.894(PSD+SSD) 7.163 ms 29.79 mm 9.08 MeV (PSD) 2.469 s 30.91 mm 36.75 MeV TOF 44.61 ns 30.33 mm 23-July-2004 18:55 (JST) 1 st chain 262 Db 204.05 MeV(PSD) 40.9 s 30.25 mm 278 113 274 111 270 Mt 266 Bh CN 11.52 MeV (PSD) 4.93 ms 30.16 mm 0.88+10.43=11.31 MeV (PSD+SSD) 34.3 ms 29.61 mm 2.32 MeV (escape) 1.63 s 29.45 mm 9.77 MeV (PSD) 1.31 s 29.65 mm 36.47 MeV TOF 45.69 ns 30.08 mm 2-April-2005 2:18 (JST) 209 Bi + 70 Zn 278 113 + n 262 Db 192.32 MeV(PSD) 0.787 s 30.47 mm 2 nd chain s.f. = 23 fb 1st chain Slide 30 2008/9/17International School of Nuclear Physics at Erice 30 10 s 1ms 0.1s 10s 1000s 278 113 = 2.6 ms 274 Rg = 21.8 ms 270 Mt = 0.82 s 266 Bh = 1.89 s 262 Db = 20.8 s T_decay/s RIKEN N=165 N=163 N=161 N=159 N=157 Slide 31 2008/9/17International School of Nuclear Physics at Erice 31 Hindrance Factor (T exp /T calc ) Systematics by Viola & Seaborg a=1.81040, b=-21.7199, c=-0.26488, d=-28.1319 by Smolanczuk, Phys. Rev. C56(1997)812 112 Ds Hs Sg Rf 113 Rg Mt Bh neutron number 166 164162 160158 0.1 156 1 10 100 1000 Slide 32 248 Cm( 18 O,5n) 261 Rf Dose: 6.310 17 Chamber: 49 kPa He: 2 L/min KCl: 620 o C Coll. step: 30 s 7 up detectors Dose: 6.310 17 Chamber: 49 kPa He: 2 L/min KCl: 620 o C Coll. step: 30 s 7 up detectors spectrum of MANONGARIS efficiency 261 Rf a 68 s 261 Rf a 68 s 257 No 25 s 257 No 25 s 8.28 MeV 8.22, 8.32 MeV 2009/1/2032Periodic Table of D.I. Mendeleev. The new superheavy elements No background peaks at > 8 MeV 161 (58 -) / 8.2-h meas. B = 1.750.02 Tm, B/B = 12.71.9% GARIS eff.: 7.81.7% for 100 mm ( = 13 nb) Gas-jet eff.: 5212% No background peaks at > 8 MeV 161 (58 -) / 8.2-h meas. B = 1.750.02 Tm, B/B = 12.71.9% GARIS eff.: 7.81.7% for 100 mm ( = 13 nb) Gas-jet eff.: 5212% Slide 33 Preliminary 248 Cm( 22 Ne,5n) 265 Sg 4 chains 257 No 14 s 257 No 14 s 265 Sg a 3.2 s 265 Sg a 3.2 s 261 Rf a 48 s 261 Rf a 48 s 8.31 8.27 8.85 8 chains 265 Sg b 24 s 265 Sg b 24 s 261 Rf b 1.5 s 261 Rf b 1.5 s 8.66 257 No 265 Sg b 261 Rf b 15.9 s 8.57 32.2 s 8.18 56.2 s 8.80 1 chain 257 No 265 Sg b 261 Rf a 18.3 s 8.38 17.2 s 8.29 33.5 s 8.69 1 chain 257 No 25 s 257 No 25 s 8.69 265 Sg 9 s 16 s 265 Sg 9 s 16 s 261 Rf 68 s3 s 8.51, SF8.28 8.22, 8.32 8.85 14 correlations (35 /fission events) on 265 Sg, 261 Rf, and 257 No B = 2.070.01 Tm, B/B = 8.41.1% 14 correlations (35 /fission events) on 265 Sg, 261 Rf, and 257 No B = 2.070.01 Tm, B/B = 8.41.1% Dllmann and Tler: PRC 77, 064320 (2008). 2009/1/2033Periodic Table of D.I. Mendeleev. The new superheavy elements Slide 34 2008/9/17International School of Nuclear Physics at Erice 34 Summary I 208 Pb( 58 Fe,n) 265 Hs, 208 Pb( 64 Ni,n) 271 Ds, 209Bi Pb( 64 Ni,n) 272 Rg, 208 Pb( 70 Zn,n) 277 112, and 209 Bi( 70 Zn,n) 278 113 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 Slide 35 2008/9/17International School of Nuclear Physics at Erice 35 Summary II 278 113 was produced by 209 Bi( 70 Zn,n) reaction. 278 113( ) 274 Rg( ) 270 Mt( ) 266 Bh( ) 262 Db(SF) Identification was based on connected to the known decays 266 Bh( ) 262 Db(SF) reaction energy systematics cross section systematics Z & A of 278 113 are largest ones among the isotopes produced by cold fusion reaction. Slide 36 2008/9/17International School of Nuclear Physics at Erice 36 Summary III (preliminary) 264 Hs(108) was produced by 207 Pb( 58 Fe,n) and 208 Pb( 58 Fe,2n) reaction. confirmation, spectroscopic information of even-even nucleus. 263 Hs(108) was produced and identified by 206 Pb( 58 Fe,n), and reaction 208 Pb( 56 Fe,n). new isotope Off line experiment for the chemistry of superheavy element coupled to a Recoil Separator using hot fusion reactions started. Slide 37 2008/9/17International School of Nuclear Physics at Erice 37 Slide 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. 2009/1/2038Periodic Table of D.I. Mendeleev. The new superheavy elements Slide 39 2008/9/17International School of Nuclear Physics at Erice 39 Thank you for your attention. Slide 40 2009/1/20Periodic Table of D.I. Mendeleev. The new superheavy elements 40 Slide 41 2008/9/17International School of Nuclear Physics at Erice 41 248 Cm Target 50,000,000 JPY Slide 42 2008/9/17International School of Nuclear Physics at Erice 42 Research in future Science of heavy elements 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 Slide 43 2008/9/17International School of Nuclear Physics at Erice 43 yearstartstophours /days dose/sum [x 10 19 ] [fb] error+error- 20039/512/291389/57.91.24/1.2475.3(upper limit) 20047/88/2526/21.90.51/1.755513045 20051/201/2372/3.00.07/1.825212043 3/234/22650/27.10.71/2.537510049 5/195/2148/2.00.05/2.58749848 8/78/25386/16.10.45/3.03638340 9/710/20937/39.01.17/4.20455929 11/2512/15469/19.50.63/4.83395125 20063/145/151300/54.21.37/6.20314020 20081/93/311701/70.92.28/8.48233015 7477/312 Total 2 events 20044/25/24694/28.90.44440590290 Z=112 Z=113 Slide 44 (pb) E( 64 Ni) /MeV (lab.) RIKEN GSI 208 Pb + 64 Ni 271 Ds + n statistical (1 ) errors energy loss in the target Excitation function of 208 Pb( 64 Ni,n) 271 Ds Slide 45 2008/9/17International School of Nuclear Physics at Erice 45 252 Md 256 Lr 260 Db 264 Bh 268 Mt 272 111 =5.5ms =30ms =1.3s =2.2s =27s (sec) =27s Journal of Physical Society of Japan (JPSJ) Vol. 73, (2004) 1738 - 1744 Slide 46 Excitation function of 209 Bi( 64 Ni,n) 272 111