Fig. 13 mass distributions obtained for $E^*_{tot} \!=\! 26\,$MeV without taking evaporation into account with the experimental mass distribution. We have considered in the theoretical calculations three different frictions : $25 \%$ of the wall and window value, $20 \%$ and $15 \%$.

The experimental analysis has exhibited a multi-modal fission-fragment mass distribution [@CS02] composed of three modes : the symmetric one and two asymmetric modes centered around mass $A \!=\! 132$ corresponding to the double magic $^{132}$Sn nucleus and around mass $A \!=\! 140$ related to the deformed $^{140}$Ba nucleus, explained [@BG90; @IVP00] by the closure of the deformed neutron shell $N \!=\! 84$. The comparison with our predictions shows that in the case of a friction corresponding to $15 \%$ of the wall-and-window value the model reproduces quite well the symmetric fission mode. We would like to mention here that microscopic calculations performed by Hofmann and Ivanyuk [@HIR01] indicate that such a reduced viscosity is about what is to be expected at such low excitation energy. However our calculation gives only rise to the asymmetric $A \!=\! 132$ channel, the $A = 140$ mode being absent.\
${}$ $\;\; 0.25 \; w \& w 
\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\; 0.2 \; w \& 