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The interplay of the effects of geometry and collective motion on d – α correlation functions is investigated for central Xe + Au collisions at E / A = 50 MeV . The data cannot be explained without collective motion, which could be partly along the beam axis. A semi-quantitative description of the data can be obtained using a Monte Carlo model, where thermal emission is superimposed on collective motion. Both the emission volume and the competition between the thermal and collective motion influence significantly the shape of the correlation function, motivating new strategies for extending intensity interferometry studies to massive particles.

A new high resolution, charged particle detector array, LASSA, has been developed. LASSA consists of nine individual telescopes that each utilizes a Si–Si–CsI(Tl) stack to provide isotopic identification of fragments (1⩽Z⩽8) with good angular resolution over a wide dynamic range in energy. The energy range covered is E/A=2.4– 140 MeV for protons and E/A=4.8– 335 MeV for 16O ions. The front portion of each telescope is comprised of a 65 μm Si(IP) strip detector backed by a 500 μm Si(IP) strip detector. This second detector provides position information in two dimensions. Behind the second silicon detector is a cluster of four 6 cm thick CsI(Tl) crystals, each read-out by a photodiode. The design, construction, and performance characteristics of this detector telescope are described.

This article describes the crystal selection and quality control utilized to develop and calibrate a high resolution array of CsI(TI) scintillator crystals for the detection of energetic charged particles. Alpha sources are used to test the light output variation due to thallium doping gradients. Selection of crystals with better than 1% non-uniformity in light output is accomplished using this method. Tests with 240 MeV alpha beam reveal that local light output variations within each of the tested CsI(TI) crystals limit the resolution to about 0.5%. Charge and mass dependences in the energy - light output relationship are determined by calibrating with energetic projectile fragmentation beams., Comment: 24 pages, 7 figures

Collisions of 112Sn and 124Sn nuclei, which differ in their isospin asymmetry, provide information about the rate of isospin diffusion and equilibration. While several different probes can provide accurate diffusion measurements, the ratios of the mirror nuclei may be the simplest and most promising one. Ratios of the mass seven mirror nuclei yields are analyzed to show the rapidity, transverse momentum and impact parameter dependence of isospin diffusion., 22 pages, 7 figures

The characteristics of intermediate mass fragments (IMFs: 3, 13 pages, 15 figures

Alpha particles emitted from an excited projectile-like fragment (PLF*) formed in a peripheral collision of two intermediate-energy heavy ions exhibit a strong preference for emission towards the target-like fragment (TLF). The interplay of the initial deformation of the PLF* caused by the reaction, Coulomb proximity, and the rotation of the PLF* results in the observed anisotropic angular distribution. Changes in the shape of the angular distribution with excitation energy are interpreted as being the result of forming more elongated initial geometries in the more peripheral collisions., 4 figures

Isotopic yields for light particles and intermediate mass fragments have been measured for central $^{112}\mathrm{Sn}+^{112}\mathrm{Sn}$, $^{112}\mathrm{Sn}+^{124}\mathrm{Sn}$, $^{124}\mathrm{Sn}+^{112}\mathrm{Sn}$, and $^{124}\mathrm{Sn}+^{124}\mathrm{Sn}$ collisions at $E∕A=50\phantom{\rule{0.3em}{0ex}}\text{MeV}$ and compared with predictions of stochastic mean field calculations. These calculations predict a sensitivity of the isotopic distributions to the density dependence of the asymmetry term of the nuclear equation of state. However, the secondary decay of the excited fragments modifies significantly the primary isotopic distributions and these modifications are rather sensitive to theoretical uncertainties in the excitation energies of the hot fragments. The predicted final isotope distributions are narrower than the experimental data and the sensitivity of the predicted yields to the density dependence of the asymmetry term is reduced.

Generalized isoscaling relationships are proposed that may permit one to relate the isotopic distributions of systems that may not be at the same temperature. The proposed relationships are applied to multifragmentation excitation functions for central Kr+Nb and Ar+Sc collisions., 20 pages, 5 figures

The defining characteristics of fragment emission resulting from the non-central collision of 114Cd ions with 92Mo target nuclei at E/A = 50 MeV are presented. Charge correlations and average relative velocities for mid-velocity fragment emission exhibit significant differences when compared to standard statistical decay. These differences associated with similar velocity dissipation are indicative of the influence of the entrance channel dynamics on the fragment production process.

A three parameter scaling relationship (termed isoscaling) between isotopic distributions for elements with Z⩽8 has been observed for a variety of reaction mechanisms that are dominated by phase space, including evaporation, multifragmentation, and deeply inelastic scattering. For multifragmentation processes, the parameters characterizing isoscaling are shown to be sensitive to the density dependence of the asymmetry term of the equation of state. Such sensitivity is discussed within the context of the Exanding Evaporating Source model and an isospin dependent dynamical model of nuclear collisions.

Ratios of the populations of ground and excited states of He-4, Li-5, and Be-8 and double ratios constructed from the yields He-3,He-4, Li-6,Li-7,Li-8, C-11,C-12,C-13 isotopes were measured for central Kr+Nb collisions at E/A = 35, 70, 100, and 120 MeV. These ratios were analyzed to estimate an apparent temperature for emission. Consistent and approximately constant apparent temperatures were obtained from the excited states of He-4, Li-5, and Be-8 nuclei and from thermometers based upon the yields of carbon isotopes. In contrast, apparent temperatures obtained from thermometers based upon the ratios using helium isotopes increase monotonically with incident energy.

Isotope ratios of fragments produced at mid-rapidity in peripheral and central collisions of 114Cd ions with 92Mo and 98Mo target nuclei at E/A = 50 MeV are compared. Neutron-rich isotopes are preferentially produced in central collisions as compared to peripheral collisions. The influence of the size (A), density, N/Z, E*/A, and Eflow/A of the emitting source on the measured isotope ratios was explored by comparison with a statistical model (SMM). The mid-rapidity region associated with peripheral collisions does not appear to be neutron-enriched relative to central collisions., Comment: 12 pages including figures

Projectile-like fragments (PLF:15, 5 pages, 6 figures