C. Marchetta

Characterization of the silicon+

Abstract The worldwide need to replace 3 He for neutron detection has triggered research and development on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6 Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to that of 3 He tubes.

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The structure of the halo nuclei is expected to influence the fusion mechanism at energies around and below the Coulomb barrier. Here new data of 4He+64Zn at sub-barrier energies are presented which cover the same energy region of previous measurements of 6He+64Zn. The fusion cross section was measured by using an activation technique where the radioactive evaporation residues produced in the reaction were identified by the X-ray emission which follows their electron capture decay. By comparing the two system, we observe an enhancement on the fusion cross section in the reaction induced by 6He, at energy below the Coulomb barrier. It is shown that this enhancement seems to be due to static properties of halo 2n 6He nucleus.

LiF thermal neutron detection technique

Intermediate energy heavy ion collisions are unique probes to study the properties of nuclei far away from the nuclear ground state. The CHIMERA detector is a powerful second generation 4/spl pi/ array conceived to study nuclear reactions at intermediate energies. The array has 1192 detection cells covering almost 95% of total solid angle. The CHIMERA device operated at the Laboratori Nazionali del Sud in Catania in four campaigns in 2000, 2003, 2004 and 2005, showing very good performances in the detection and identification capabilities. Experimental results are presented, together with the improvement in progress to extend further the detection and identification capabilities.

Halo effects on fusion cross section in 4,6He+64Zn collision around and below the coulomb barrier

6 pags., 5 figs. -- 12th International Spring Seminar on Nuclear Physics, IOP Conf. Series. -- Open Access funded by Creative Commons Atribution Licence 3.0

Particle identification with the 4/spl pi/ CHIMERA detector array

The use of the stacked target technique to measure fusion cross-sections of reactions induced by low intensity radioactive beams offers considerable advantages since several reaction energies may be simultaneously measured. The main disadvantage of the method is the degradation of the beam quality as it passes through the stack due to statistical nature of energy loss processes and any non-uniformity of the stacked targets. This degradation can lead to ambiguities of associating effective beam energies to reaction product yields for the targets within the stack. A detailed investigation of these ambiguities has been performed and some of the obtained results are presented.

Experimental investigation of exotic clustering in 13B and 14C using the resonance scattering method

Fusion cross sections for the 6Li+120Sn and 7Li+119Sn systems have been measured. We aim to search for possible effects due to the different neutron transfer Q-values, by comparing the fusion cross sections for the two systems below the barrier. This experiment is the first step of a wider systematic aiming to study the above problems in collisions induced by stable and unstable Li isotopes on tin all forming the same compound nucleus.

Measuring fusion excitation functions with RIBs: A thorough analysis of the stacked target technique and the related problems

New fusion data for the {sup 4}He+{sup 64}Zn system at sub-barrier energies are measured to cover the same energy region of previous measurements for {sup 6}He+{sup 64}Zn. Aim of the experiment was to compare the fusion excitation functions for the two system to investigate on the effects of the {sup 6}He neutron-halo structure on the fusion reaction mechanism at energies around the Coulomb barrier. The fusion cross section was measured by using an activation technique. Comparing the two systems, we observe an enhancement of the fusion cross section in the reaction induced by {sup 6}He, at and below the Coulomb barrier.

Fusion reactions in collisions induced by Li isotopes on Sn targets

The study of reaction mechanisms in collisions induced by halo and/or weakly bound nuclei around the barrier has recently been the subject of many theoretical and experimental papers. Here we discuss our recent results concerning the study of the systems 13N+9Be and 6He+64Zn.