Nuclear stopping from 0.09A to 1.93A GeV and its correlation to flow.

We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV.

Azimuthal dependence of collective expansion for symmetric heavy-ion collisions.

Detailed studies of the azimuthal dependence of the mean fragment and flow energies in the Au+Au and Xe+CsI systems are reported as a function of incident energy and centrality. Comparisons between data and model calculations show that the flow energy values along different azimuthal directions could be viewed as snapshots of the fireball expansion with different exposure times. For the same number of participating nucleons more transversally elongated participant shapes from the heavier system produce less collective transverse energy.

Simulation of neutron interactions at the single-cell level.

We recently reported that the exposure of cancer cells to 14 MeV neutrons at a very low dose rate (0.8 mGy min(-1)) produced a marked increase in cell killing at 5 cGy, followed by a plateau in survival and chromosomal damage. Simulation of the energy deposition events in irradiated cells may help to explain these unusual cell responses.

Simulation code for the interaction of 14 MeV neutrons on cells.

The structure of the survival curve of melanoma cells irradiated by 14 MeV neutrons displays unusual features at very low dose rate where a marked increase in cell killings at 0.05 Gy is followed by a plateau for survival from 0.1 to 0.

Effects of low-dose neutrons applied at reduced dose rate on human melanoma cells.

Human melanoma cells that are resistant to gamma rays were irradiated with 14 MeV neutrons given at low doses ranging from 5 cGy to 1.12 Gy at a very low dose rate of 0.8 mGy min(-1) or a moderate dose rate of 40 mGy min(-1).

Isospin tracing: A probe of nonequilibrium in central heavy-Ion collisions.

Four different combinations of 9644Ru and 9640Zr nuclei, both as projectile and target, were investigated at the same bombarding energy of 400A MeV using a 4pi detector. The degree of isospin mixing between projectile and target nucleons is mapped across a large portion of the phase space using two different isospin-tracer observables, the number of measured protons and the tritium to 3He yield ratio. The experimental results show that the global equilibrium is not reached even in the most central collisions.

Exclusive measurements of light fragment production at forward angles in Ne-Pb and Ne-NaF collisions at E/A=400 MeV and 800 MeV.

Emission of light fragments at small angles is studied in relativistic heavy ion collisions using the Diogene plastic wall for both symmetrical and non-symmetrical target-projectile systems with 400 MeV per nucleon and 800 MeV per nucleon incident neon nuclei. Efficiency of multiplicity measurements in the small angle range for the selection of central or peripheral collisions is confirmed for asymmetric systems. Differential production cross sections of Z = 1 fragments show evidence for the existence of two emitting sources.

Proton production in relativistic heavy ion collisions; comparison with a thermodynamical model.

Experimental results concerning proton production in nuclear collisions, obtained at Saturne with the Diogene 4 pi facility, are compared with the predictions of a thermodynamical model, using collective velocity distributions combined with a statistical thermodynamics in local rest frames. Experimental differential cross sections for alpha + nucleus and Neon + nucleus central collisions at incident energies between 200 and 800 MeV per nucleon are well reproduced by the model, for an angular range 30-110 degrees in the laboratory system. Extracted values of the temperatures are compared with those given by other authors.

Nuclear collective flow and charged-pion emission in Ne-nucleus collisions at E/A = 800 MeV.

Triple-differential cross sections of charged pions were measured for collisions of Ne projectiles at E/A = 800 MeV with NaF, Nb, and Pb targets. The reaction plane was estimated event by event from the light-baryon momentum distribution. For heavy targets, preferential emission of charged pions away from the interaction zone towards the projectile side was observed in the transverse direction.

Proton-proton correlations at small relative momentum in neon-nucleus collisions at E/A=400 and 800 MeV.

Proton-proton small angle correlations have been measured in neon-nucleus collisions, using the 4 pi detector Diogene, at 400 and 800 MeV per nucleon incident energies. Values of the size of the emitting region are obtained by comparison with the Koonin formula, taking into account the biases of the apparatus. The dependence of the density on target mass and incident energy is also analysed.

Exclusive measurements of mean pion multiplicities in 4He-nucleus reactions from 200 to 800 MeV/nucleon.

Mean multiplicities of pi+ and pi- in 4He collisions with C, Cu, and Pb at 200, 600, and 800 MeV/u, and with C and Pb at 400 MeV/u have been measured using the large solid angle detector Diogene. The independence of pion multiplicity on projectile incident energy, target mass and proton multiplicity is studied in comparison with intra-nuclear cascade predictions. The discrepancy between experimental results and theory is pointed out and discussed.

The Diogene 4 pi detector at Saturne.

Diogene, an electronic 4 pi detector, has been built and installed at the Saturne synchrotron in Saclay. The forward angular range (0 degree-6 degrees) is covered by 48 time-of-flight scintillator telescopes that provide charge identification. The trajectories of fragments emitted at larger angles are recorded in a cylindrical 0.