Exploring the stability of super heavy elements; First measurement of the fission barrier of No

Henning, G.*; Lopez-Martens, A.*; Khoo, T. L.*; Seweryniak, D.*; Alcorta, M.*; Asai, Masato  ; Back, B. B.*; Bertone, P. F.*; Boilley, D.*; Carpenter, M. P.*; Chiara, C. J.*; Chowdhury, P.*; Gall, B.*; Greenlees, P. T.*; Gurdal, G.*; Hauschild, K.*; Heinz, A.*; Hoffman, C. R.*; Janssens, R. V. F.*; Karpov, A. V.*; Kay, B. P.*; Kondev, F. G.*; Lakshmi, S.*; Lauritsen, T.*; Lister, C. J.*; McCutchan, E. A.*; Nair, C.*; Piot, J.*; Potterveld, D.*; Reiter, P.*; Rowley, N.*; Rogers, A. M.*; Zhu, S.*

Fission barrier heights of No have been determined through the entry distribution method. The entry distribution is the initial distribution of excitation energy and spin from which the deexcitation starts in the fusion-evaporation reaction. The initial distribution is extracted from measured -ray multiplicity and total -ray energy. This paper describes the details of the entry distribution method, and reports the first determination of the fission barrier heights of No, which is the heaviest nucleus whose fission barrier has been measured.