Abstract
The Legnaro National Laboratories are one of the four INFN laboratories and they are mainly dedicated to experimental nuclear physics and astrophysics, within the field of nuclear structure ...and dynamics, where heavy ion induced reactions at medium-low energies are involved. Moreover, high level technologies for the construction of particle accelerators and experimental instruments and apparatuses are studied and developed. The laboratory is at present involved in the construction of the SPES facility, which concerns the development of a new research infrastructure devoted to the production of exotic beams for nuclear physics study and new radioisotopes for nuclear medical applications. The heart of SPES is an innovative cyclotron, B70, capable of providing high intensity proton beams (up to 750 μA) in the energy range between 35 and 70 MeV. A description of the present and future challenges at the Legnaro National Laboratory will be given.
The possibility to detect fast neutrons as a distinct signal from that one of γ-rays background is surely of great importance for several topics, spanning from homeland security to radiation ...monitoring in nuclear physics research plants. Nowadays, Helium-3 based detectors are extremely expensive, while the use of large volume liquid scintillators presents serious concerns related to spillage risks and waste disposal. A very attractive alternative is the use of commercially available solid scintillators, which exploits an aromatic polymer matrix entrapping very high loadings of primary dye, thereby enabling the use of pulse shape analysis (PSA) to discriminate between fast neutrons and γ-rays. In this work, we analyse in detail the optical features of a solid scintillator composed by polymethylphenylsiloxane (PMPS) as base polymer loaded with moderate amounts of 2,5-diphenyloxazole (PPO). Furthermore, fluorescence decay kinetics have been correlated to the observed pulse shape discrimination capabilities of this radiation and thermally resistant scintillator, whose performances have been discussed in terms of conformational features and excimers formation revealed by the optical analyses.
The Isotope Separation On-Line (ISOL) method for the production of Radioactive Ion Beams (RIB) is attracting significant interest in the worldwide nuclear physics community. Within this context the ...SPES (Selective Production of Exotic Species) RIB facility is now under construction at INFN LNL (Istituto Nazionale di Fisica Nucleare Laboratori Nazionali di Legnaro). This technique is established as one of the main techniques for high intensity and high quality beams production. The SPES facility will produce n-rich isotopes by means of a 40 MeV proton beam, emitted by a cyclotron, impinging on a uranium carbide multi-foil fission target. The aim of this work is to describe the most important results obtained by the study of the on-line behavior of the SPES production target assembly. This target system will produce RIBs at a rate of about 1013 fissions per second, it will be able to dissipate a total power of up to 10 kW, and it is planned to work continuously for 2 week-runs of irradiation. ISOL beams of 24 different elements will be produced, therefore a target and ion source development is ongoing to ensure a great variety of produced isotopes and to improve the beam intensity and purity.
The FAZIA apparatus exploits Pulse Shape Analysis (PSA) to identify nuclear fragments stopped in the first layer of a Silicon-Silicon-CsI(Tl) detector telescope. In this work, for the first time, we ...show that the isotopes of fragments having atomic number as high as Z∼20 can be identified. Such a remarkable result has been obtained thanks to a careful construction of the Si detectors and to the use of low noise and high performance digitizing electronics. Moreover, optimized PSA algorithms are needed. This work deals with the choice of the best algorithm for PSA of current signals. A smoothing spline algorithm is demonstrated to give optimal results without requiring too much computational resources.
A systematic analysis of the data obtained by the FAZIA collaboration during a recent experiment with a neutron rich projectile is presented. The main goal was to compare the experimental results ...with the HIPSE event generator simulations to investigate the influence of the neutron rich entrance channel on the quasi-projectile fragment properties. The full isotopic range of charged particles detected in this experiment was within the limit of the resolution of the FAZIA detector. A majority of quasi-projectile fragments were detected thanks to the forward angular acceptance of the experimental setup which was confirmed through the HIPSE calculations. Essentially, the lowering of
N
/
Z
of quasi-projectile fragments with the beam energy was found to be present since the initial phase of the reaction. Thus, pre-equilibrium neutron emissions might be a possible candidate to explain such an effect.
Abstract A systematic analysis of the data obtained by the FAZIA collaboration during a recent experiment with a neutron rich projectile is presented. The main goal was to compare the experimental ...results with the HIPSE event generator simulations to investigate the influence of the neutron rich entrance channel on the quasi-projectile fragment properties. The full isotopic range of charged particles detected in this experiment was within the limit of the resolution of the FAZIA detector. A majority of quasi-projectile fragments were detected thanks to the forward angular acceptance of the experimental setup which was confirmed through the HIPSE calculations. Essentially, the lowering of N / Z of quasi-projectile fragments with the beam energy was found to be present since the initial phase of the reaction. Thus, pre-equilibrium neutron emissions might be a possible candidate to explain such an effect.
The energy loss profiles of different ion beams (6Li, 27Al and 50Ti) impinging on CF4, isobutane and P10 have been measured with the active target ACTAR TPC demonstrator. The pressure of the gas, ...monitored during the experiment, has been chosen in order to stop the ions inside the active zone. Starting from the energy loss calculation produced by the SRIM code, the experimental ion tracks have been simulated, taking into account the effect of the thermal diffusion of electrons during their drift towards the pad plane under the effect of a uniform electric field. The uncertainty in the geometry, mainly due to the thickness and deformation of the mylar interface window between the gas volume and the high vacuum line, has been taken into account. A good agreement is obtained between the experimental and simulated energy loss profiles.
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