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

超重元素の安定性の探究; Noの核分裂障壁の初測定

Henning, G.*; Lopez-Martens, A.*; Khoo, T. L.*; Seweryniak, D.*; Alcorta, M.*; 浅井 雅人  ; 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.*

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.*

初期状態分布法によりNoの核分裂障壁の高さを決定した。初期状態分布とは、核融合-粒子蒸発反応によって励起された原子核が線放出による脱励起を開始する励起エネルギーとスピンの状態を二次元で表示したものであり、線多重度と全線エネルギーの測定から求めることができる。本論文では、初期状態分布法の詳細を詳しく記述し、Noの核分裂障壁の高さを初めて決定した実験結果について報告する。なお、Noは核分裂障壁が測定された最も重い原子核である。

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.