S. Pesente

Experimental determination of the symmetry energy of a low density nuclear gas

Experimental analyses of moderate-temperature nuclear gases produced in the violent collisions of 35 MeV/nucleon Zn-64 projectiles with Mo-92 and Au-197 target nuclei reveal a large degree of alpha particle clustering at low densities. For these gases, temperature- and density-dependent symmetry energy coefficients have been derived from isoscaling analyses of the yields of nuclei with A <= 4. At densities of 0.01 to 0.05 times the ground-state density of symmetric nuclear matter, the temperature- and density-dependent symmetry energies range from 9.03 to 13.6 MeV. This is much larger than those obtained in mean-field calculations and reflects the clusterization of low-density nuclear matter. The results are in quite reasonable agreement with calculated values obtained with a recently proposed virial equation of state calculation.

The EXPLODET project: advanced nuclear techniques for humanitarian demining

Thermal neutron activation and fast neutron scattering are known to be a useful tool to detect hidden explosives which present an elevated concentration of nitrogen and peculiar elemental ratio for light elements (C, N, O). Such characteristics can be suitably optimized to detect the small amount of explosives contained in anti-personnel mines (APM) disseminated in former war theatres. We report here on a research program aimed at defining a conceptual design of a field operated system for APM detection based on neutron induced reactions. ( 1999 Elsevier Science B.V. All rights reserved.

Laboratory Tests of Low Density Astrophysical Nuclear Equations of State

Clustering in low density nuclear matter has been investigated using the NIMROD multidetector at Texas A&M University. Thermal coalescence modes were employed to extract densities, ρ, and temperatures, T, for evolving systems formed in collisions of 47A MeV (40)Ar+(112)Sn, (124)Sn and (64)Zn+(112)Sn, (124)Sn. The yields of d, t, (3)He, and (4)He have been determined at ρ=0.002 to 0.03 nucleons/fm(3) and T=5 to 11 MeV. The experimentally derived equilibrium constants for α particle production are compared with those predicted by a number of astrophysical equations of state. The data provide important new constraints on the model calculations.

Light output of EJ228 scintillation neutron detectors.

The light output of neutron detectors based on the plastic scintillator EJ228 is studied as a function of neutron energy using a time tagged (252)Cf source. Calibration of the light output scale is performed by fitting the experimental distribution of Compton scattering events of photons from a (22)Na source with a response function obtained by Gaussian smearing of the predicted line-shape. The light output curve as well as the pulse height resolution for the EJ228 scintillators is very close (within 5%) to those recently reported for NE213 type organic liquid scintillators.

Nuclear matter symmetry energy at 0.03(ρ/ρ0)0.2

Measurements of the density dependence of the free symmetry energy in low density clustered matter have been extended using the NIMROD multi-detector at Texas A&M University. Thermal coalescence models were employed to extract densities,

Effects of soil moisture on the detection of buried explosives by radiative neutron capture

\rho

Experimental Determination of In-Medium Cluster Binding Energies and Mott Points in Nuclear Matter

, and temperatures,

A new facility for non-destructive assay using a 252Cf source.

T

Simulation of a tagged neutron inspection system prototype

, for evolving systems formed in collisions of 47

Alpha Conjugate Neck Structures in the Collisions of 35 MeV/nucleon 40Ca with 40Ca

A