CERN Accelerating science

Preprint
Report number	JINR-P7-2005-106 ; P7-2005-106
Title	Some Peculiarities in the Interaction of $^{6}$He with $^{197}$Au and $^{206}$Pb
Author(s)	Penionzhkevich, Yu E ; Astabatyan, R A ; Demekhina, N A ; Dlouhý, Z ; Kalpakchieva, R ; Kulko, A A ; Lobastov, S P ; Lukyanov, S M ; Markaryan, E R ; Maslov, V A ; Muzycjka, Yu A ; Oganessian, Yu T ; Rassadov, D N ; Skobelev, N K ; Sobolev, Yu G ; Ugryumov, V Yu ; Vincour, J ; Zholdybaev, T
Affiliation	(Nuclear Physics Institute ASCR, Revz, Czech Republic) ; (Yerevan Physics Institute, Armenia) ; (Institute of Nuclear Physics, Almaty, Kazakhstan) ; (Flerov Laboratory of Nuclear Reactions, Dubna)
Publication	2005
Imprint	13 Jul 2005
Number of pages	11
Published in:	Pis'ma v Echaya
Subject category	Nuclear Physics
Abstract	Excitation functions were measured for fusion followed by the evaporation of neutrons in the reactions $^{206}$Pb($^{6}$He, 2$n$)$^{210}$Po and $^{197}$Au($^{6}$He, $xn$)$^{203 - xn}$Tl, where $x$ = 2-7, as well as for the transfer reactions on a $^{197}$Au target with the formation of the $^{196}$Au, $^{198}$Au and $^{199}$Au isotopes. The experiment was carried out at the Dubna Radioactive Ion Beams (DRIBs) complex of FLNR, JINR. The $^{6}$He-beam intensity was about 5$\cdot$10$^{6 }$ s$^{-1}$, the maximum energy being (60.3$\pm $0.4) MeV. A significant increase in the cross section was observed below the Coulomb barrier for the fusion reaction with the evaporation of two neutrons compared to statistical model calculations. Unusual behaviour for the production of $^{198}$Au is observed, whereas the cross section for the formation of $^{199}$Au is very low. The analysis of the data in the framework of the statistical model for the decay of excited nuclei, which took into account the sequential fusion of $^{6}$He, has shown good agreement between the experimental and the calculated values of the cross sections for the case of sub-Coulomb-barrier fusion in the $^{206}$Pb + $^{6}$He reaction.
Submitted by	[email protected]