Towards saturation of the electron-capture delayed fission probability: The new isotopes ²⁴⁰Es and ²³⁶Bk

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• 作者：J. Konki^a ; J. Khuyagbaatar^b ; ^c ; ^{J.Khuyagbaatar@gsi.de} ; J. Uusitalo^a ; P.T. Greenlees^a ; K. Auranen^a ; ¹ ; H. Badran^a ; M. Block^b ; ^c ; ^d ; R. Briselet^e ; D.M. Cox^f ; ² ; M. Dasgupta^g ; A. Di Nitto^c ; ^d ; Ch.E. Dü ; llmann^b ; ^c ; ^d ; T. Grahn^a ; K. Hauschild^h ; A. Herzá ; n^a ; ³ ; R.-D. Herzberg^f ; F.P. Heß ; berger^c ; D.J. Hinde^g ; R. Julin^a ; S. Juutinen^a ; E. Jä ; ger^c ; B. Kindler^c ; J. Krier^c ; M. Leino^a ; B. Lommel^c ; A. Lopez-Martens^h ; D.H. Luong^g ; M. Mallaburnⁱ ; K. Nishio^j ; J. Pakarinen^a ; P. Papadakis^a ; J. Partanen^a ; P. Peura^a ; ⁴ ; P. Rahkila^a ; K. Rezynkina^h ; P. Ruotsalainen^a ; M. Sandzelius^a ; J. Saré ; n^a ; C. Scholey^a ; J. Sorri^a ; S. Stolze^a ; B. Sulignano^e ; Ch. Theisen^e ; A. Ward^f ; A. Yakushev^b ; ^c ; V. Yakusheva^b ; ^c
• 关键词：Isotopes with mass 236&ndash ; 240 ; 240Es ; 236Bk ; α decay ; Electron-capture delayed fission ; Fusion&ndash ; evaporation reactions
• 刊名：Physics Letters B
• 出版年：2017
• 出版时间：10 January 2017
• 年：2017
• 卷：764
• 期：Complete
• 页码：265-270
• 全文大小：1252 K
• 卷排序：764

文摘

The new neutron-deficient nuclei 240Es and 236Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240Es produced in the fusion–evaporation reaction 209Bi(34S,3n)240Es. Half-lives of 6(2)s and 22−6+13s were obtained for 240Es and 236Bk, respectively. Two groups of α   particles with energies Eα=8.19(3)MeV and 8.09(3)MeV were unambiguously assigned to 240Es. Electron-capture delayed fission branches with probabilities of 0.16(6)0.16(6) and 0.04(2)0.04(2) were measured for 240Es and 236Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes.