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تسجيل مستخدم جديدProduction cross section and decay study of $^{243}$Es and $^{249}$Md
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R. Briselet
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In the study of the odd-$Z$, even-$N$ nuclei $^{243}$Es and $^{249}$Md, performed at the University of Jyvaskyla, the fusion-evaporation reactions $^{197}$Au($^{48}$Ca,2$n$)$^{243}$Es and $^{203}$Tl($^{48}$Ca,2$n$)$^{249}$Md have been used for the first time. Fusion-evaporation residues were selected and detected using the RITU gas-filled separator coupled with the focal-plane spectrometer GREAT. For $^{243}$Es, the recoil decay correlation analysis yielded a half-life of $24 pm 3$s, and a maximum production cross section of $37 pm 10$ nb. In the same way, a half-life of $26 pm 1$ s, an $alpha$ branching ratio of 75 $pm$ 5%, and a maximum production cross section of 300 $pm$ 80 nb were determined for $^{249}$Md. The decay properties of $^{245}$Es, the daughter of $^{249}$Md, were also measured: an $alpha$ branching ratio of 54 $pm$ 7% and a half-life of 65 $pm$ 6 s. Experimental cross sections were compared to the results of calculations performed using the KEWPIE2 statistical fusion-evaporation code.
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