Red Emitting Phenyl-Polysiloxane Based Scintillators for Neutron Detection

status: publishe

Pulse Shape Discrimination in Polysiloxane-Based Liquid Scintillator

The time response of a recently developed polysiloxane based liquid scintillator has been analyzed for the first time: a special focus on the pulse shape discrimination capability of this material, which is characterized by low toxicity and low volatility, has been addressed. Fluorescence lifetime and scintillation pulses have been studied at different primary dye concentrations, with the aim of optimizing the neutron/gamma discrimination, connecting the results to the energy transfer and to the formation of excimers inside the scintillating solution. Pulse shape analysis performed during the irradiation of the samples with a pulsed neutron beam allowed the definition of a figure of merit as an indicative parameter for the neutron/gamma discrimination. The dependence of this parameter from radiation energy and PPO concentration has been analyzed in order to optimize the performances of the material in view of its possible use in environments with high gamma-ray radiation background

New investigations on the

The 32S(3He,d)33Cl one-proton transfer reaction is a powerful tool to investigate the spectroscopy of low-lying states in the proton-rich 33Cl nucleus. However, the extraction of firm differential cross-section data at various angles to benchmark and constrain theoretical models is made challenging by the presence of competitive reactions on target contaminants. In this paper we report on arecent measurement using a new generation hodoscope of silicon detectors, capable to detect and identify emitted deuterons down to energies of the order of 2 MeV. The high angular segmentation of our hodoscope combined with a suitable target to control possible contaminants, allowed to unambiguously disentangle the contribution of various states in 33Cl, in particular the 2.352 MeV state lying just few tens of keV above the proton separation energy

New investigations on the 32S(3He,d)33Cl reaction at 9.6 MeV bombarding energy

The 32S(3He,d)33Cl one-proton transfer reaction is a powerful tool to investigate the spectroscopy of low-lying states in the proton-rich 33Cl nucleus. However, the extraction of firm differential cross-section data at various angles to benchmark and constrain theoretical models is made challenging by the presence of competitive reactions on target contaminants. In this paper we report on arecent measurement using a new generation hodoscope of silicon detectors, capable to detect and identify emitted deuterons down to energies of the order of 2 MeV. The high angular segmentation of our hodoscope combined with a suitable target to control possible contaminants, allowed to unambiguously disentangle the contribution of various states in 33Cl, in particular the 2.352 MeV state lying just few tens of keV above the proton separation energy

Comparative study of four reactions at onset of pre-equilibrium emission

The study of the emitted particles, comparing pre-equilibrium and thermal components, is a useful tool to examine the nuclear structure of emitters. Possible clustering effects, which may change the expected decay chain probability, could be highlighted on the competition between different reaction mechanisms. The NUCL-EX collaboration (INFN, Italy) has carried out an extensive research campaign on pre-equilibrium emission of light charged particles from hot nuclei. In this framework, the reactions 16O+30Si, 18O+28Si, 19F+27Al at 7 AMeV and 16O+30Si at 8 AMeV have been carried out using the GARFIELD+RCo array at Legnaro National Laboratories. Some anomalies in the α-particle emission channels have been evidenced in the measurement reported above, showing in an exclusive way the observed effects related to the entrance channels. The experimental results are compared to model prediction, for which the same filtering and complete event selection have been applied

Comparative study of four reactions at onset of pre-equilibrium emission

The study of the emitted particles, comparing pre-equilibrium and thermal components, is a useful tool to examine the nuclear structure of emitters. Possible clustering effects, which may change the expected decay chain probability, could be highlighted on the competition between different reaction mechanisms. The NUCL-EX collaboration (INFN, Italy) has carried out an extensive research campaign on pre-equilibrium emission of light charged particles from hot nuclei. In this framework, the reactions 16O+30Si, 18O+28Si, 19F+27Al at 7 AMeV and 16O+30Si at 8 AMeV have been carried out using the GARFIELD+RCo array at Legnaro National Laboratories. Some anomalies in the α-particle emission channels have been evidenced in the measurement reported above, showing in an exclusive way the observed effects related to the entrance channels. The experimental results are compared to model prediction, for which the same filtering and complete event selection have been applied

Clustering in light nuclei and their effects on fusion and pre – equilibrium processes.

International audienceThe study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is important to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions [1–5]. The NUCL–EX collaboration has recently initiated an experimental campaign of exclusive measurements of fusion–evaporation reactions with light nuclei as interacting partners. In collisions involving light systems, the low expected multiplicity of fragments increases the probability of achieving a quasi-complete reconstruction of the event. In particular the formation and decay modes of an excited 24Mg system have been studied through two different reactions, 12C (95 MeV)+ 12C and 14N (80.7 MeV)+ 10B, which have been used to produce fused systems with nearly the same mass and excitation energy (~60 MeV). In particular, even the de-excitation of the Hoyle state in 12C have been studied, both in peripheral (projectiles de-excitation) and in central collisions (six α-particles channel). Moreover, a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei has been carried out. For this purpose, a comparative study of the three nuclear systems 18O+28Si, 16O+30Si and 19F+27Al has been recently studied using the GARFIELD+RCo 4π setup [6]. The experimental data are compared with the predictions of simulated events generated with the statistical models (GEMINI++ and HFl) and through dynamical models like Stochastic Mean Field (SMF) and Antisymmetrized Molecular Dynamics (AMD) and filtered with a software replica of our apparatus in order to take into account the experimental conditions