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We have performed the measurement of the 27Al(α, n) cross section at IFIN-HH for a range of energies from 2.5 to 5.2 MeV, using an array of 28 3He counters arranged in 3 concentric rings (ELIGANT-TN). Here we present the experimental setup and discuss the role of the 13C contamination which effects the measurements in the low-energy region. Energy-dispersive X-ray spectroscopy carried out before and after the experiment suggested an increase in the 13C concentration during the experiment.

Much of North America's civil infrastructure is rapidly aging and, in some cases, exceeding its design life and load. To combat this, the exploration of simple and effective methods for rehabilitation and structural health monitoring has been receiving much attention in industry and academia. This paper reports on the use of the impact resonance method (IRM) for evaluating the structural health of thermal-cycled reinforced concrete (RC) beams with and without externally strengthened carbon-fibre-reinforced polymer (CFRP) pultruded plates. In the experimental program, 1.2 m long specimens were subjected to 55 thermal cycles ranging from +23 to -18 °C. Fatigue loading consisting of up to two million cycles at high and low stress levels was performed. At pre-determined load cycle intervals, the loading was stopped and the IRM was performed on the specimens. Parameters including the appearance of the fast Fourier transform (FFT) spectrum of the specimens' vibration, modal fundamental frequencies, and dynamic properties were used to assess damage in the specimen. Conclusions were made regarding the use of the IRM in monitoring the health of strengthened and unstrengthened RC beams subjected to thermal and fatigue cycles. Key words: impact resonance method, nondestructive testing, durability, strengthened concrete beam, fatigue. Resume: La majorite des infrastructures civiles d'Amerique du Nord vieillit rapidement et, dans certains cas, depasse la duree de vie et les charges nominales. Pour combattre cet etat de fait, la recherche de methodes simples et efficaces de restauration et de suivi de la sante structurale a suscite l'interet de l'industrie et des universitaires. Le present article traite de l'utilisation de la methode de resonance ultrasonique (<< IRM >>) pour evaluer la sante structurale des poutres en beton aime soumises a un cyclage thermique avec et sans plaque pultrudee de renfort externe en polymeres renforces de fibres de carbone. Lors du programme experimental, des echantillons d'une longueur de 1,2 m ont ete soumis a 55 cycles thermiques variant de 23 a -18 °C. La charge de fatigue consistait en deux millions de cycles a des niveaux de contrainte eleve et faible. A des intervalles de cycle de charge predetermines, le chargement a ete interrompu et les echantillons ont ete soumis a << IRM >>. Les parametres, dont l'apparence du spectre de la transformee de Fourier rapide de la vibration des echantillons, les frequences modales fondamentales ainsi que les proprietes dynamiques ont ete utilisees pour evaluer les dommages aux echantillons. Des conclusions ont ete tirees quant a l'utilisation de << IRM >> pour le suivi de l'etat des poutres en beton arme renforcees et non renforcees soumises a des cycles thermiques et de fatigue. Mots-cles: methode de resonance ultrasonique, essais non destructifs, durabilite, poutre en beton arme, fatigue. [Traduit par la Redaction], Introduction Aging civil infrastructure is a problem that faces much of North America as many structures are approaching the end of their design life. Infrastructure has become damaged due to [...]

Engineered targets are expected to play a key role in future high-power laser experiments calling for joined, extensive knowledge in materials properties, engineering techniques and plasma physics. In this work, we propose a novel patterning procedure of self-supported 10 μm thick Au and Cu foils for obtaining micrometre-sized periodic gratings as targets for high-power laser applications. Accessible techniques were considered, by using cold rolling, electron-beam lithography and the Ar-ion milling process. The developed patterning procedure allows efficient control of the grating and foil surface on large area. Targets consisting of patterned regions of 450 μm × 450 μm, with 2 μm periodic gratings, were prepared on 25 mm × 25 mm Au and Cu free-standing foils, and preliminary investigations of the micro-targets interacting with an ultrashort, relativistic laser pulse were performed. These test experiments demonstrated that, in certain conditions, the micro-gratings show enhanced laser energy absorption and higher efficiency in accelerating charge particle beams compared with planar thin foils of similar thickness. [ABSTRACT FROM AUTHOR]