Fast Neutron Detection with 6Li-loaded Liquid Scintillator

We report on the development of a fast neutron detector using a liquid scintillator doped with enriched Li-6. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene-based liquid scintillator. A Li-6 concentration of 0.15 % by weight was obtained. A 125 mL glass cell was filled with the scintillator and irradiated with fission-source neutrons. Fast neutrons may produce recoil protons in the scintillator, and those neutrons that thermalize within the detector volume can be captured on the Li-6. The energy of the neutron may be determined by the light output from recoiling protons, and the capture of the delayed thermal neutron reduces background events. In this paper, we discuss the development of this 6Li-loaded liquid scintillator, demonstrate the operation of it in a detector, and compare its efficiency and capture lifetime with Monte Carlo simulations. Data from a boron-loaded plastic scintillator were acquired for comparison. We also present a pulse-shape discrimination method for differentiating between electronic and nuclear recoil events based on the Matusita distance between a normalized observed waveform and nuclear and electronic recoil template waveforms. The details of the measurements are discussed along with specifics of the data analysis and its comparison with the Monte Carlo simulation

Etude Sur Prototype Et Par Simulation D'un Detecteur D'antineutrinos A Base De Scintillateur Charge Au Lithium-6

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Une méthodologie de conception robuste en dynamique des structures

International audienceThe tools of modeling and multicriterion optimization the most employed in the structural dynamics rests on the finite element methods and the genetic algorithms. Although the progress in the data-processing field make it possible to treat models comprising several million degrees of freedom, the costs of calculations especially remain a significant obstacle within the framework of the optimization of complex structures in the presence of uncertainties (geometrical, material) on the parameters of design. It then becomes necessary to reduce the size of the models by using a robust base of Ritz.Les outils de modélisation et d'optimisation multicritères les plus employés en dynamique des structures reposent sur la méthode des éléments finis et les algorithmes génétiques. Bien que les avancées dans le domaine informatique permettent de traiter des modèles comportant plusieurs millions de degrés de liberté, les coûts de calculs restent un obstacle important dans le cadre de l'optimisation de structures complexes surtout en présence des incertitudes (géométriques, matérielle) sur les paramètres de conception. Il devient alors nécessaire de réduire la taille des modèles en utilisant une base de Ritz robuste