Profiting from previous works done with the INDRA multidetector on the description of the light response L of the CsI(Tl) crystals to different impinging nuclei, we propose an improved ΔE−L ...identification-calibration procedure for Silicon–Caesium Iodide (Si–CsI) telescopes, namely an Advanced Mass Estimate (AME) method. AME is compared to the usual, simple visual analysis of the corresponding two-dimensional map of ΔE−E type, by using INDRA experimental data from nuclear reactions induced by heavy ions in the Fermi energy regime. We show that the capability of such telescopes to identify both the atomic Z and the mass A numbers of light and heavy reaction products, can be quantitatively improved thanks to the proposed approach. This conclusion opens new possibilities to use INDRA for studying these reactions especially with radioactive beams. Indeed, the determination of the mass for charged reaction products becomes of paramount importance to shed light on the role of the isospin degree of freedom in the nuclear equation of state 1,2.
The role of collective radial expansion in determining multifragmentation partition properties has previously been explored by comparing different-sized sources of the same excitation energy per ...nucleon formed by very different reaction mechanisms: excited quasi-projectiles from semi-peripheral Au+Au collisions and quasi-fused sources from central Xe+Sn collisions. New data has been obtained with INDRA on 181Ta+66Zn collisions in order to allow comparison of Xe+Sn data with quasi-fused systems having the same mass, charge and excitation energy per nucleon formed in mass-asymmetric reactions, for which a smaller initial compression is expected. Preliminary results confirm that, ceteris paribus, smaller radial flow leads to less fragments with more asymmetric partitions.
The simultaneous measurement of the isotopic fission-fragment yields and fission-fragment velocities of U-239 has been performed for the first time. The U-239 fissioning system was produced in ...one-neutron transfer reactions between a U-238 beam at 5.88 MeV/nucleon and a Be-9 target. The combination of inverse kinematics at low energy and the use of the VAMOS + + spectrometer at the GANIL facility allows the isotopic identification of the full fission-fragment distribution and their velocity in the reference frame of the fissioning system. The proton and neutron content of the fragments at scission, their total kinetic and total excitation energy, as well as the neutron multiplicity were determined. Information from the scission point configuration is obtained from these observables and the correlation between them. The role of the octupole-deformed proton and neutron shells in the fission-fragment production is discussed.
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