[en] Fragments at large angle from a heavy ion collision could result from the condensation into clusters of nucleons from a hot zone of unbond nuclear matter. Analogy with the condensation of a vapour into droplets leads to predict a mass distribution of fragments of the form (dσ/dA) proportional to Asup(-tau) with(tau) approximately= 2.33. In another proposed mechanism, nearly the whole ensemble projectile + target breaks into pieces due to the high excitation brought in by the collision. Preliminary data from the reaction Ar + Au at 44 MeV/u are examined in the light of the two descriptions

[en] Preliminary data relative to the production of light and medium-mass fragments in the following reactions: ⁴⁰Ar + ¹⁹⁷Au at 44 MeV/u, ²⁰Ne + ¹⁹⁷Au at 38,50 and 60 MeV/u, ²⁰Ne + Ag at 50 and 60 MeV/u, are compared to predictions of three models implying evaporation, cold break-up or expansion-condensation of a fireball. A limit is tentatively given to the stability of excited nuclei at a temperature around 5 MeV

[en] A detailed study was made of the different processes which may compete with fusion in the energy domain where the cross section for fusion deviates from the reaction cross section. Both reactions ¹⁴N + ¹²C and ¹⁶O + ¹⁰B were used to form the compound nucleus ²⁶Al at the same excitation energy of 44 MeV

[en] Recent experiments were performed in which charged particles or neutrons are detected in coincidence with γ rays from the interaction of protons and pions with nuclei; they give new information upon yields, energy spectra and multiplicities of emitted particles and ions as a function of resolved exit channels. Such problems as fragmentation, initial and final state interactions, cluster effects or absorption mechanism are discussed from the new data. 9 references

[en] The aim of the present investigation is to determine the entrance channel conditions to form nuclei as hot as possible and also to study their decay properties. The experiment has been realised at the GANIL facility using ¹⁴N, ⁴⁰Ar, and ⁵⁸Ni projectiles at intermediate energies and with beam intensities ranging from 100 to 500 nA. The technique we used to determine the linear momentum imparted to the target nucleus is the angular correlation of the fission products, whereas energies deposited in nuclei were deduced from the measurement of masses and velocities of both fission fragments. In summary, important amount of momentum transfers and excitation energies have been imparted to composite-like-nuclei with A approximately 270. A scaling for momentum transfer with the projectile mass is evidenced up to the Ni ions for central collisions. Velocity and size of projectiles play an important role as well as excitation energies deposited in fissioning nuclei, in fixing the central collision cross sections. Finally, high relative velocities of fission fragments have been measured and open an interesting problem on the fission properties of nuclei at high excitation energies and angular momenta

[en] Fission fragment angular correlations for the system ⁵⁸Ni + ²³²Th at 20, 25 and 30 MeV/u show still a bump for large momentum transfers which suggest that its disappearance for the ⁴⁰Ar + ²³²Th system at 44 MeV/u is not due to a limitation in the excitation energy and that the size and velocity of projectiles are also important. High relative velocities of fission fragments are measured for large transfers (approximately 9.5 GeV/c), this could be due to more exotic fission of hot nuclei

[en] Light particles (p,d,t,₃He) energy spectra from 70 MeV/nucleon α on ₁₉₇Au have been measured at angles ranging from 10₀ to 30₀ in the laboratory. The results have been analysed in terms of fragmentation and moving thermal source models. It is shown that α induced data display similar features as heavy ions data

[en] In this report, the experimental results we obtained on the momentum transfers in the light and heavy ion reactions induced at Saturne (proton, deuton, alpha particle from 35 to 1000 MeV/u) and Ganil (⁴⁰Ar, 44 MeV/u) will be presented. The talk will be concentrated on the three main topics: i) Classification of the reaction mechanisms determined by the average linear momentum imparted to the target nuclei. ii) Evolution of the full momentum transfer probabilities with projectile masses and energies. iii) Limits of the highest momentum and excitation energies which can be transferred to a nucleus. In most of our experiments, the fission fragment angular correlation technique was used in order to determine the linear momentum transfer

[en] 'Diogene' is the name of a 4π solid angle detector, based on a Time Projection Chamber (TPC), designed to perform exclusive measurements of charged particles emitted in central collisions of relativistic heavy ions. Exclusive measurements of all charged particles emitted in central collisions of relativistic heavy ions are becoming more and more necessary in this field of nuclear physics in order to answer some crucial questions such as: what is the degree of compression achieved in these collisions. What is the behavior of nuclear matter at high degree of excitation as well as compression. The possibility of handling high multiplicities up to 40 or 60; a momentum measurement of all particles, with not too bad a resolution, up to about 1.5 GeV/c; a good particle identification between π^+-, p, d, t ..

[en] γ rays from nuclei bombarded by high energy protons (from 100 MeV to 1 GeV) lead to mass distributions of stable nuclei where 4n-nuclei are the most abundant. With calcium an energy dependence is found. Some evidence for direct or semi-direct processes is reported