Mass scaling of reaction mechanisms in intermediate energy heavy ion collisions

Reaction mechanisms have been studied for two nearly symmetrical systems of different total mass, between 25 and 74 A MeV. It is shown that collisions an mostly binary whatever the system mass and the bombarding energy. From the slowing-down of the partners, it is possible to establish the continuou s evolution from quasielastic to (completely) damped collisions. It turns o ut that results are independent of the total system mass if involved energi es are expressed in A MeV. The occurrence of mid-rapidity emission is also considered and may be used to establish a link between mechanisms observed at low and high bombarding energy. Part of it corresponds to a fast decay o f outgoing partners. (C) 2000 Elsevier Science B.V. All rights reserved.