Experimental evidence of primary
emission of light
particles from compound nuclei prior to fission, 3-body or
many-body breakup, A. Chbihi, Grand
Accélérateur National d'Ions Lourds (GANIL), Caen,
France − Collisions of
Xe+Sn at energy range of E/A = 8 to 30 MeV and leading to
fusion-like heavy
residues are studied using the 4π INDRA multidetector. The energy spectra of
light charged particles
(LCP) in coincidence with one-, 2- or many-body residues have been
analyzed. It reveals
that a composed system is formed,
it is highly excited and first decays by emitting LCP’s and then
may breakup
into 2- or many- fragments or survives as an evaporative residue.
A quantitative
estimation of this primary
emission is given and compared to the secondary decay of the
fragments. These
analysis indicate that most of
evaporative LCP precedes not only fission but also precedes
breakup into
several fragments. This founding put hard constraints on dynamical
and
statistical multifrgamentation models.