Programme Advisory Committee for Nuclear Physics 33th meeting, January 2011 FLNR Radiochemical Research. Present Status and 7-year Plan S. Dmitriev 2 Identification and Study of Chemical Properties of New Elements of the Mendeleev Periodic Table 3 IVVVI HfTaW 1966 I.Zvara et al. Gas-phase Chemistry HfCl 4 TaBr 5 WO 2 Cl 2 HfCl 4 TaBr 5 WO 2 Cl 2 104Cl 4 105Br 5 106O 2 Cl 2 CHEMISTRY OF TRANSACTINIDES (Z>103) Zr 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 6 72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg Rf 105 Db 106 Sg 107 Bh 108 Hs 109 Mt 110 Ds 111 RgCn RfCl 4 DbCl 5 SgO 2 Cl 2 BhO 3 ClHsO 4 RfBr 4 DbBr Rf( ) 262,263 Db( ) 266 Sg( ,SF) 267 Bh( ) 269 Hs( ) 268 Mt( ) 271 Ds( ) 272 Rg( ) 277 Cn( ) 78 s 30 s 21 s17 s9.7 s21 ms1,6 ms3,8 ms0.69 ms Number of observed decay chains Element Element Element Element Element Element 112 8 Relatively long half-lives of isotopes of elements produced in reactions with 48 Ca and chemical properties of SHE predicted theoretically permit new experiments aimed at: the chemical identification of SHE, study of their chemical properties, determination of masses of the SHE isotopes ~20 s Of-line chemical separation of 268 Db Z=115 Nb / Ta / Db - fraction Dmitriev S N et al., Mendeleev Commun.15 (2005) 1 Schumann D et al., Radiochim. Acta 93 (2005) 727 Stoyer N J et al., Proc.9th Int. Conf. NN Collisions,Brazil, 28 Aug.1 Sep Oganessian Yu Ts et al., Phys. Rev. C 69 (2004) Transactinides 15 events 48 Ca Am N Sample (data) t irr hr Beam Dose E bot +E top + 1 n (t,c) t detect hr t measurement hr 1 (12.06) 20 2,5 n (5;64) (13.06) 22 3,710 17 n (57) (14.06) 22 3,4 n (3) n (8;16) (15.06) 22 2,9 n (2) n (151) n (89) (17.06) 38 6,7 n (6,98) n (4,31,43) n n (6,41) (18.06) 23 3,9 n (2,2) (19.06) 22 3,6 (21.06) 45 7,4 n (5;33) n (72,165) n (12,19,29) 3, 9 Spontaneous fission half-life of 268 Db (N=163) T 1/2 = 32 h 15 events 252 Cf 268 Db Q F ~ 280 MeV Mendeleev periodic table of the elements (2010) 11 GAS PHASE CHEMISTRY WITH ELEMENTS 112 AND 114 Are elements 112 and 114 volatile metals? How do relativistic effects influence the chemistry of E112 and of E114? contraction and stabilization of s and p 1/2 orbitals expansion and destabilization of d and f orbitals SO splitting of p, d, f orbitals j = l s j = l s R e (7s) = 20% scale as ~ Z 2 Relativistic effects 13 How to determine experimentally a metallic character of a volatile element at a single atom level? Determine interaction energy (adsorption enthalpy) with noble metals (e.g. Au) If metallic: strong interaction (adsorption enthalpy) if non-metallic (noble gas like): weak interaction Reaction: 242 Pu (48 Ca,3n) [0.5s ] [3.6s ] Compound Hg(Au) and 112(Au) Observed in Chemistry: s 9.54 MeV s MeV 279 Ds 0.18 s SF(>90%) 205 MeV Reported at FLNR: Oganessian et al ms 10.7 MeV The Observation Dubna 2006/2007 Eichler, R. et al. Nature (2007) Experiments with element C -5C -26C -44C on gold -126C on ice 242 Pu ( 48 Ca, 3n) weeks: 6*10 18 of 48 Ca 17 48 Ca Pu 48 Ca Pu s 9.53 MeV MeV 279 Ds 0.24 s SF s 9.54 MeV s MeV 279 Ds 0.18 s SF DGFRSDGFRS ChemistryChemistry ads = -88 C 18 48 Ca Pu 48 Ca Pu MeV :109 ms SF ms SF s 9.95 MeV ads = -84 C DGFRSDGFRS ChemistryChemistry 19 Result from the chemistry experiment with element 114 Element 114 exhibits a very weak interaction with Au - pointing to a physisorptive interaction (similar to a noble gas). A quantitative description of this behaviour is lacking so far. The results obtained up to 2010 (synthesis of new elements with atomic numbers 113, 114, 115, 116 and 118, investigation of their nuclear and chemical properties, first experimental observation of the influence of relativistic effects on the chemical behavior of SHE) served as a starting for the new 7-year program for 2010 2016. FLNR main directions of studies according to the JINR 7-year plan ( ) 1. Synthesis of superheavy elements and study of their properties; 2. Chemistry of SHE; 3. Investigation of spontaneous and induced fission; 4. Mass-spectrometry and nuclear spectroscopy of isotopes of heavy and transfermium elements; 5. Study of mechanisms of reactions with stable and radioactive nuclei; Accelerator operation time in the 2010: U hours U400M4570 hours 22 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 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 Dimitrovgrad, RF (Dated: April 1, 2010) The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes and 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 Z111, validating the concept of the long sought island of enhanced stability for super-heavy nuclei 23 DGFRS Chemistry of the Element MeV 3.6 s Mt 276 Rg MeV 0.72 s Bh 272 SF TKE = 205(5) MeV 16 h 9.02 MeV 9.8 s Db Am + 48 Ca 3n MeV 0.48 s 2222 4444 3333 5555 111 MeV 87 ms (9) MeV MeV 222 3333 SF TKE = 218(5) MeV 38 s Rg (8) MeV 9.48(11) MeV 9.96 MeV (8) MeV MeV 1111 7.9 s 1.2 s 0.32 s 0.22 s 21 ms 10 ms (40) MeV MeV 222 (10) MeV 9.43 MeV Mt 278 4444 Rg 282 3333 9.55(19) MeV 9.14 MeV Bh 274 5555 SF TKE = 219(5) MeV 33.4 h 6666 8.80(10) MeV 8.43 MeV Db (10) MeV 9.56 MeV (10) MeV MeV 1111 1.3 min 7.4 min 11.0 s 13 s 0.74 s 8.1 s 28.3 s 16 s s 1.0 s 112 ms 45 ms Bk + 48 Ca 24 Target ( 249 Bk ; 0,5 mg/cm 2 ) SiO 2 - Ta 800C (4 ) (4 ) He/Ar (70/30) CHEMISTRY OF THE 113 ELEMENT Au pairs 2.5m 1 L/min 25 16 pairs of gold covered detectors 26 Target 249 Bk (0.5 mgcm -2 ) nat Nd (30 gcm -2 ) 48 Ca E mid. target = 252 MeV I ~ 9 eA Irradiation: ; target I - 3.510 18 ; target II - 5.6 Ca Bk 27 Alpha and SF spectra DGFRS 04 May :05:4616 May :29:54 Bk-target I Bk-target II 222 MeV s Mt 278 4444 Rg 282 333 MeV 6.49 s Bh 274 5555 SF MeV h 666 MeV min Db Bk + 48 Ca 3n 9.62 MeV 1111 Bot (40) MeV MeV 222 (10) MeV 9.43 MeV Mt 278 4444 Rg 282 3333 9.55(19) MeV 9.14 MeV Bh 274 5555 SF TKE = 219(5) MeV 33.4 h 6666 8.80(10) MeV 8.43 MeV Db (10) MeV 9.56 MeV (10) MeV MeV 1111 1.3 min 7.4 min 11.0 s 13 s 0.74 s 8.1 s 28.3 s 16 s s 1.0 s 112 ms 45 ms E* = 35 MeV 1 event 222 MeV 1.85min Mt 278 4444 Rg 282 3333 Bh 274 5555 SF MeV h 666 MeV