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Viola and the Heavy Elements W. Loveland Oregon State University.

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Presentation on theme: "Viola and the Heavy Elements W. Loveland Oregon State University."— Presentation transcript:

1 Viola and the Heavy Elements W. Loveland Oregon State University

2 Vic’s Contributions to the Heavy Element Field Vic’s Nucleus Systematics of the properties of the heaviest elements TKE release in fission Linear Momentum Transfer Transfer Product Yields

3 Vic’s Nucleus--The “Union Card” Grad student in the Seaborg group Numerous important contributions 226 U Current data t 1/2 =0.35 s, E  =7.57 MeV

4 Systematics of the properties of the heaviest elements Masses, Q , Q  V.E. Viola, Jr. and G.T. Seaborg, J. Inorg Nucl.Chem. 28, 697 (1966). V.E. Viola, Jr., J. A. Swant, and J. Graber, At. Data and Nucl Data Tables 13, 35 (1974). (Z=50-118, A= ) Lifetimes V.E. Viola, Jr. and G.T. Seaborg, J. Inorg. Nucl Chem. 28, 741 (1966) V.E. Viola, Jr. and B.D. Wilkins, Nucl. Phys. 82, 65 (1966)

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8 TKE Release in Fission V.E. Viola, Jr. Nucl. Data A1, 391 (1966) V.E. Viola, K. Kwiatkowski, and M. Walker, Phys. Rev. C (1985). Simple-Minded Approach Simple fit to the data Pocket formula Viola Systematics-1966 Viola systematics-1985 Note limits on range of applicability

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10 Physics Issues r 0 ~ 1.8  2R + D D  Initial Kinetic Energy of Fragments

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12 New Developments

13 Linear Momentum Transfer T. Sikkeland, E.L. Haines, and V.E. Viola, Jr., Phys. Rev 125, 1350 (1962) V,E. Viola, et al., Phys, Rev. C 26,178 (1982). p frag p CN /2 Diagnostic for the occurrence of incomplete fusion A tool to study the mechanism of intermediate energy colliisions

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16 Transfer Product Yields

17 Heavy Element Synthesis

18 Search for Element 112 in the 238 U( 48 Ca,3n) Reaction Y.T. Oganessian et al. reported (Eur. J. Phys A5, 63 (1999)) 231 MeV 48 Ca U    SF Two events were observed (t ½ = 81 (+147, -32) s) Dose = 3.5 x 10 18,  = 5.0 (+6.3, - 3.2) pb Somewhat unexpected decay mode

19 What is so special about and its synthesis? occurs in the decay of formed in the 245 Cm + 48 Ca reaction occurs in the decay of formed in the 244 Pu + 48 Ca reaction should be the most easily reachable hot fusion product.

20 Chronology of Studies of 238 U( 48 Ca,3n) Reaction Vassilissa group reports synthesis of with  ~ 5 pb, t 1/2 ~ 3 m, decay =SF, E lab =231 MeV BGS group fails to find ,  upper ~ 0.9 pb, 0

21 Summary of BGS Experiments

22 RESULTS NO SF events in any irradiation No EVR-  -  correlations ( T < 20 s) in any irradiation.

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24 Summary of Experiments Vassilissa group is SF nucleus, with t 1/2 ~ 5 min,  ~ 4 pb DGFRS group is  emitter (SF < 10%), t 1/2 = 6 s,  ~ 2.5 pb GSI group is SF nucleus, t 1/2 ~ 5 s,  ~ 0.7 pb BGS group not found,  upper ~ 0.9 pb

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26 Thanks, Vic


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