A recent analysis of experimental ternary fission fragment yields using a nucleation moderated statistical equilibrium model reproduced observed yields with fairly good accuracy. In the present work, the same approach is applied to neck emission in peripheral and mid-peripheral 124Sn+112,124Sn collisions at 26A MeV. The model can reasonably reproduce the yields of lithium to silicon isotopes with realistic time and temperature values. A comparison is made between equilibrium constants derived from the present data and those previously obtained for ternary fission of 242Pu.
Isotopic yields for light particles and intermediate mass fragments have been measured for 112Sn+112Sn, 112Sn+124Sn, 124Sn+112Sn and 124Sn+124Sn central collisions at E/A=50 MeV and compared with predictions of stochastic mean field calculations. These calculations predict a sensitivity of the isotopic distributions to the density dependence of the asymmetry term of the nuclear equation of state. However, the secondary decay of the excited fragments modifies significantly the primary isotopic distributions and these modifications are rather sensitive to theoretical uncertainties in the excitation energies of the hot fragments. The predicted final isotope distributions are narrower than the experimental data and the sensitivity of the predicted yields to the density dependence of the asymmetry term is reduced.
The de-excitation of alpha-conjugate nuclei produced in reactions of 35 MeV/nucleon 40Ca with 40Ca has been investigated. Particular emphasis is placed on examining the dynamics of collisions leading to projectile-like fragment exit channels. A general exploration of the reaction systematics reveals the binary dissipative character of the collisions and a hierarchy effect similar to that seen for heavier systems. Investigation of the subset of events characterized by a total alpha-conjugate mass (alpha particles plus alpha-conjugate fragments) equal to 40 and atomic number equal to 20 reveals a dominance of alpha-conjugate exit channels. The hierarchy effect for these channels leads to the production of alpha-clustered neck structures with potentially exotic geometries and properties.
Experimental kinetic energy distributions and small-angle two-particle correlation functions involving deuterons and tritons are compared for 36Ar+ 112,124Sn collisions at E/A = 61 MeV (i.e. for systems similar in size, but with different isospin content). A larger triton yield is observed from the more neutron-rich system, as predicted by IBUU simulations, while the emission times of the light clusters are found to be the same for the two Sn-target systems. For both systems, the time sequence tau_{d} < tau_{p} < tau_{t}, is deduced for charged particles emitted from the intermediate velocity source.
Dissipative 12C+12C reactions at 95 MeV are fully detected in charge with the GARFIELD and RCo apparatuses at LNL. A comparison to a dedicated Hauser-Feshbach calculation allows to select events which correspond, to a large extent, to the statistical evaporation of highly excited 24Mg, as well as to extract information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain. Residual deviations from a statistical behaviour are observed in alpha yields and attributed to the persistence of cluster correlations well above the 24Mg threshold for 6 alphas decay.
Small-angle, two-particle correlation functions have been measured for 36Ar+ 112,124Sn collisions at E/A = 61 MeV. Total momentum gated neutron-proton (np) and proton-proton (pp) correlations are stronger for the 124Sn-target. Some of the correlation functions for particle pairs involving deuterons or tritons (nd, pt, and nt) also show a dependence on the isospin of the emitting source.
J. Gauthier
,M. Barbui
,X. Cao
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(2018)
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"A nucleation model analysis of neck emission yields in 124Sn+112,124Sn reactions at 26 MeV/nucleon"
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Jerome Gauthier
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