G. V. Russo

Characterization technique of sub-millimeter scintillating fibers

The characterization of sub-millimeter scintillating optical fibers involves the measurement of the attenuation length, which is one of the main properties together with the yield and the trapping efficiency, given the use of these fibers in the design of particle detectors. Every technique considered allows for the optical coupling of the scintillating fibers to suitable photo sensors, at one or both ends. What essentially changes is the cause of scintillation light within the fibers, which comes from a UV laser or radioactive source. We have developed an alternative technique that is based on the use of cosmic rays as a uniform scintillation source. In this paper we present the results of this method compared to others obtained using standard ones.

Neutron production in coincidence with fragments from the 4Ca+H reactions at Elab=357 and 565 A MeV

In the frame of the Transport Collaboration neutrons in coincidence with charged fragments produced in the 40Ca+H reaction at Elab=357 and 565 A MeV have been measured at the Heavy Ion Spectrometer System (HISS) facility of the Lawrence Berkeley National Laboratory, using the multifunctional neutron spectrometer MUFFINS. The detector covered a narrow angular range about the beam in the forward direction (0°–3.2°). In this contribution we report absolute neutron production cross sections in coincidence with charged fragments (10⩽Z⩽20). The neutron multiplicities have been estimated from the comparison between the neutron cross sections, in coincidence with the fragments, and the elemental cross sections. We have found evidence for a pre-equilibrium emission of prompt neutrons in superposition to a ‘slower’ deexcitation of the equilibrated remnant by emission of nucleons and fragments, as already seen in the inclusive rapidity distributions.

Neutron Production from the 40 Ca + H Reaction at E lab = 357 and 565A MeV

Fragmentation processes in nuclear collisions at intermediate energies are currently among the most widely studied topics both from an experimental and a theoretical point of view. They are not only essential tools for studies of the nuclear equation of state (EOS)1, 2, 3, 4, 5 but are also of great interest in astrophysics6, 7.

The Scaling Function of Nuclear Matter

In two recent publications [1, 2], the EOS Collaboration has presented the first model independent determination of four critical exponents for nuclear matter based on the analysis of exclusive nuclear multifragmentation data obtained in 1 GeV/nucleon collisions of gold on a carbon target at the Lawrence Berkeley Bevalac. These studies were motivated in part by the striking resemblance nuclear multifragmentation data has with many aspects of critical phenomena [3, 4, 5]. In reference [2], the critical exponent σ was determined assuming that the multifragmentation data would exhibit the type of scaling expected for systems possessing critical behavior. In this paper, we demonstrate that this is indeed the case, and we determine for the first time the scaling function of nuclear matter.

Photon intensity interferometry with multidetectors

Abstract The technique of two-photon interferometry in heavy ion collisions at the intermediate energies is discussed and the importance of a new methodology, used in the treatment of the experimental data, is evidenced. For the first time, both the relative momentum, qrel, and the relative energy, q0, of the two correlated photons have been simultaneously used to extract the source size and lifetime of the emitting source. As an application, the performances of the BaF2 ball of the MEDEA multidetector as a photon intensity interferometer have been evaluated. The response of such a detector to correlated pairs of photons has been studied through full GEANT3 simulations. The effects of the experimental filter on the photon correlation function have been investigated, and the noise, induced in the correlation signal by cosmic radiation, neutral pion decay, and γ-conversion, has also been estimated.