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Neutron fluences were measured from 435 MeV/nucleon Nb ions stopping in a Nb target and 272 MeV/nucleon Nb ions stopping in targets of Nb and Al for neutrons above 20 MeV and at laboratory angles between 3 degrees and 80 degrees. The resultant spectra were integrated over angles to produce neutron energy distributions and over energy to produce neutron angular distributions. The total neutron yields for each system were obtained by integrating over the angular distributions. The angular distributions from all three systems are peaked forward, and the energy distributions from all three systems show an appreciable yield of neutrons with velocities greater than the beam velocity. Comparison of the total neutron yields from the two Nb + Nb systems suggests that the average neutron multiplicity decreases with decreasing projectile energy. Comparison of the total yields from the two 272 MeV/nucleon systems suggests that the total yields show the same dependence on projectile and target mass number as do total inclusive neutron cross sections. The data are compared with Boltzmann-Uehling-Uhlenbeck model calculations.

Populations of excited 5 Li and 6 Li fragments have been measured for the 3 He + Ag reaction at 200 MeV. At forward angles, fragments emitted via preequilibrium mechanisms display population probabilities that are consistent with emission temperatures of about 4 MeV, comparable to other measurements of preequilibrium processes. In contrasts, fragments emitted to backward angles display much smaller population probabilities consistent with emission temperatures of about 1 MeV. Such low temperatures are consistent with residue excitation energies predicted by molecular dynamics calculations.

Azimuthal correlations of particles emitted in collisions between 197Au target nuclei and projectiles 36Ar (at E A = 35, 50, 80 and 110 MeV ) and 129Xe (at E A = 50 MeV ) have been measured with the MSU Miniball, a 4π phoswich array with a low detection threshold. Various impact parameter filters, based on the charge-particle multiplicity, transverse energy and midrapidity charge are tested by their ability to suppress collective motion as measured by the azimuthal correlations. The usefulness of a directivity cut in selecting central collisions for these systems is evaluated.

Both two-deuteron and two-proton correlation functions, at small relative momenta, have been measured for [sup 14]N+[sup 27]Al collisions at [ital E]/[ital A]=75 MeV. Data are compared to the predictions of a microscopic transport model which incorporates deuteron production and Coulomb interactions. The results indicate that deuterons are emitted over a shorter time span than protons.

Proton and deuteron azimuthal distributions with respect to the reaction plane have been measured as a function of associated charged-particle multiplicity for 36Ar+197Au collisions at E A = 35 MeV . Quantitative corrections for the dispersion of experimentally determined reaction planes about the true reaction plane have been applied. The results are compared to the predictions of a microscopic transport model which incorporates deuteron production and Coulomb effects.

Collisions between 36Ar projectiles and 197Au target nuclei at E A = 50, 80 and 110 MeV have been studied with the MSU Miniball, a 4π phoswich array with a low detection threshold. Various impact-parameter filters, based upon total charged-particle multiplicity, transverse energy, midrapidity charge and multiplicity of emitted hydrogen nuclei, are compared and cross-correlated. The relative selectivity of each prescription for small impact-parameter collisions is evaluated by assessing the suppression of fast-particle emission at forward angles.

Excitation functions have been measured for complex fragments with atomic number Z=3--15 emitted in collisions of E/A=20--100 MeV $^{14}\mathrm{N}$ ions with targets of $^{\mathrm{nat}}\mathrm{Ag}$ and $^{197}\mathrm{Au}$. The results are analyzed in terms of a three-source model which includes: projectilelike fragments from peripheral processes, nonequilibrium emission, and statistical decay of fully equilibrated compound nuclei. Nonequilibrium emission of complex fragments is found to increase rapidly relative to equilibrium emission up to E/A\ensuremath{\approxeq}60 MeV and then remain approximately constant thereafter. Evidence for enhanced production of heavier intermediate-mass fragments is found in the data for reactions with the $^{\mathrm{nat}}\mathrm{Ag}$ target at energies above E/A\ensuremath{\approxeq}60 MeV. Fit parameters for the equilibrium and nonequilibrium sources are examined. In particular, it is observed that the temperature parameter for nonequilibrium emission of complex fragments is independent of bombarding energy up to E/A=100 MeV.

Excitation functions have been measured for the formation of intermediate-mass-fragments in reactions of E/A = 20–100 MeV 14 N + nat Ag and 197 Au. The data have been analyzed in terms of a phenomenological moving-source model based on equilibrium, nonequilibrium and projectile-like sources. Systematic features of the data and the moving-source fit parameters are examined.

Two-proton correlation functions, measured at small relative momenta in the $^{3}\mathrm{He}$+Ag reaction at 200 MeV, increase monotonically with the kinetic energy of the detected particles. Very strong correlations are observed for intermediate energy protons. These correlations scale with the weaker correlation functions measured for heavier projectiles, and can be reproduced by the Boltzmann-Uehling-Uhlenbeck equation. Even stronger correlations measured for beam velocity protons, however, may be remnants of the initial state wave functions of the $^{3}\mathrm{He}$ projectiles.

Excitation functions have been measured for complex fragments with Z=3–15 emitted in collisions of E/A=60, 80 and 100 MeV 14 N ions with targets of natAg and 197Au. The results are analyzed in terms of a three-source model: projectile fragmentation, non-equilibrium emission from the composite system, and statistical decay of an equilibrated heavy residue. Enhanced heavy fragment production is found for reactions with the natAg target above E/A⩾60 MeV. Above E/A≅50 MeV the ratio of equilibrium to non-equilibrium cross sections is found to be nearly independent of bombarding energy. Fit-parameter systematics are presented.

Two-proton correlation functions have been measured at {theta}{sub lab}{approx}25{degree} for the forward kinematics'' reactions {sup 14}N+{sup 27}Al, {sup 14}N+{sup 197}Au at {ital E}/{ital A}=75 MeV, for the inverse kinematics'' reaction {sup 129}Xe+{sup 27}Al at {ital E}/{ital A}=31 MeV, and for the nearly symmetric reaction {sup 129}Xe+{sup 122}Sn at {ital E}/{ital A}=31 MeV. For the reactions at 75 MeV per nucleon, the correlation functions exhibit pronounced maxima at relative proton momenta, {ital q}{approx}20 MeV/{ital c}, and minima at {ital q}{approx}0 MeV/{ital c}. These correlations indicate emission from fast, nonequilibrium processes. They are analyzed in terms of standard Gaussian source parametrizations and compared to microscopic simulations performed with the Boltzmann-Uehling-Uhlenbeck equation. For the reactions at 31 MeV per nucleon, the two-proton correlation functions do not exhibit maxima at {ital q}{approx}20 MeV/{ital c}, but only minima at {ital q}{approx}0 MeV/{ital c}. These correlations indicate emission on a slower time scale. They can be reproduced by calculations based on the Weisskopf formula for evaporative emission from fully equilibrated compound nuclei. For all reactions, the measured longitudinal and transverse correlation functions are very similar, in agreement with theoretical predictions.

An approximate relation is derived which allows the calculation of the two-proton correlation function for any reaction model capable of predicting the classical single-particle phase-space distribution or Wigner function in the exit channel. The sensitivity of the calculated two-proton correlation functions to source radii and lifetimes is illustrated with simple parametrizations. More realistic calculations are presented for two different regimes of emission time scales: slow particle evaporation from equilibrated compound nuclei, as predicted from the Weisskopf formula, and fast nonequilibrium particle emission in intermediate-energy nucleus-nucleus collisions, as predicted from the Boltzmann-Uehling-Uhlenbeck transport equation.

Two-proton correlation functions measured for the {sup 14}N+{sup 27}Al reaction at {ital E}/{ital A}=75 MeV are compared to correlation functions predicted for collision geometries obtained from numerical solutions of the Boltzmann-Uehling-Uhlenbeck (BUU) equation. The calculations are in rather good agreement with the experimental correlation function, indicating that the BUU equation gives a reasonable description of the space-time evolution of the reaction.

Populations of particle unbound states of light nuclei were measured for the reaction 16 O+Au at E / A = 94 MeV and compared to previous results for the reactions 14 N+Au at E/A = 35 MeV and 40 Ar+Au at E/A = 60 MeV . Emission temperatures extracted from the relative populations of states are surprisingly similar for all three reactions.