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HK: Hadronen und Kerne

HK 59: Postersitzung

HK 59.5: Poster

Donnerstag, 27. März 1997, 14:00–16:30, P

The Discovery of the Long-Lived Superheavy Element Z = 112 in View of the Observation of Isomeric States coupled to the Second Well of the Potential-Energy Surfaces — •A. Marinov¹, S. Gelberg¹, and D. Kolb² — ¹Racah Institute of Physics, The Hebrew University, Jerusalem — ²Fachbereich Physik, Universität Kassel, 34109 Kassel

In 1971 [1] secondary reactions in CERN 24-GeV p + W targets indicated long-lived Z=112 in Hg sources. Masses like 308, 315 and 318 were consistently interpretated [2] as various molecules of ^272,273112 with C,N,O,Cl. In 1990 [3] ⁸⁸Sr + ¹⁸⁴W at 5.1 MeV/u gave 163.7 KeV and 29.1 KeV X-rays expected for element 112, and a coincidence 12.2 MeV α with 50 MeV fission fragment. The long observed lifetime of several weeks and the large production cross sections (20 nb in 88Sr + 184W and 1 - 10 mb in the secondary reactions) may be understood from the recent discovery [4] of long-lived isomeric states coupled to the second well of the potential-energy surfaces.

[1] A. Marinov et al., Nature 229, 464 (1971)

[2] A. Marinov, S.Eshhar, J.L. Weil and D. Kolb, Phys. Rev. Lett. 52, 2209 (1984)

[3] A.Marinov, S.Gelberg, H.Folger, D.Kolb, W.Oelert, 8th Int. Conf. on Atomic Masses and Fundamental Constants, Jerusalem 1990, L-46

[4] A. Marinov, S. Gelberg, D. Kolb, Mod. Phys. Lett. A11, 861 and 946 (1996)