• Nuclear spin conversion in the gaseous phase in the presence of a static electric field: Intramolecular magnetic interactions and the role of collisionsPeer reviewedClosed access 

      2004, LECOINTRE, Julien; Cacciani, P.; Cosléou, F.; Herlemont, F.; Khelkhal, M., HENALLUX
      Article scientifique
      When a gaseous sample of 13CH3F is prepared with a spin-isomer population ratio (ortho and para forms) far from the equilibrium given by nuclear spin statistics, it relaxes towards this equilibrium with an exponential decay rate. This phenomenon, called nuclear spin conversion, is mainly governed by intramolecular spin-spin and spin-rotation interactions which couple two pairs of quasidegenerate ...
    • Rotational dependence of the dipole moment of 13CH3FPeer reviewedClosed access 

      2004, LECOINTRE, Julien; Cosleou, J.; Cacciani, P.; Herlemont, F.; Khelkhal, M; Pracna, P., HENALLUX
      Article scientifique
      When a gas sample of 13CH3F is prepared with a population of spin isomers far from the equilibrium given by nuclear spin statistics, it relaxes towards this equilibrium with an exponential decay rate. This rate is increased by submitting the molecules to a static electric field, emphasizing the role of the magnetic intramolecular interactions and of the collisions in the “quantum relaxation” process ...
    • Mise au point d’une méthodologie permettant la quantification de condensats de vapeurPeer reviewedOpen access 

      2004, HABRAN, O.; LESCROART, Ralph, HENALLUXFoRS
      Article scientifique
      L’objet de cet article est de présenter la mise au point d’une méthodologie de quantification de condensats de vapeur issus de bains testeurs de flacons d’aérosols à L’Oréal Libramont. Cette méthodologie fait intervenir une validation des résultats obtenus via des méthodes purement théoriques, par des résultats obtenus expérimentalement. Cette quantification de condensats constituait une étape ...
    • Conception et réalisation d’un convertisseur de protocoles angulairesPeer reviewedOpen access 

      2005, COPPENS d’EECKENBRUGGE, H; RICHARD, S, HENALLUXFoRS
      Article scientifique
      Pour repérer des positions angulaires, on utilise des encodeurs reliés à un système de lecture. La communication entre ces deux interlocuteurs exige un protocole de transmission de données, majoritairement de type SSI ou ENDAT, avec une résolution comprise entre 13 et 25 bits. On désire dans ce projet réaliser un adaptateur électronique qui rende compatible des interlocuteurs de marques ...
    • Optimisation d’un logiciel de prévision d’avalanches à l’aide d’un algorithme génétique.Peer reviewedOpen access 

      2005, LENFANT, T; LESCROART, Ralph, HENALLUXFoRS
      Article scientifique
      En Ecosse, l’évaluation des risques d’avalanche se fait à l’aide d’une méthode statistique basée sur le « Principe des plus proches voisins ». C’est un algorithme génétique qui ajuste les paramètres du modèle. Ici, nous proposons quelques améliorations qui mènent à une meilleure exploitation des données disponibles. Les erreurs de prévision sont ainsi réduites de près de 20%.
    • Etude et modification d’un four de trempe de verre lui donnant la capacité de tremper du verre de 3 mm d’épaisseurPeer reviewedOpen access 

      2006, ABBELOOS, M.; BERNET, A.; CAESTECKER, A., HENALLUXFoRS
      Article scientifique
      L’étude consiste à apporter des modifications sur un four de trempe de verre dans le but de pouvoir tremper du verre de 3 mm d’épaisseur. Pour ce faire, il a fallu adapter un système additionnel d’air comprimé permettant de délivrer une plus grande pression et un plus grand débit d’air. Ainsi, la plage de trempe du four est passée d’une plage de 4 à 19 mm d’épaisseur à une plage de 3 à 19 mm ...
    • Simulateur de transitoires sur réseau électrique automobile selon ISO 7637-1Peer reviewedOpen access 

      2006, COPPENS d’EECKENBRUGGE, H; GEORGES, S., HENALLUXFoRS
      Article scientifique
      Le travail consiste en la réalisation d’un générateur de signaux électriques transitoires destiné aux tests de contrôleurs sur réseau électrique automobile. Le générateur sera intégré dans le circuit électronique à la place de la batterie 12 V et simulera différents signaux transitoires pouvant affecter la tension de la batterie. Les caractéristiques de ces différentes tensions transitoires ...
    • A crossed-beam experiment for electron impact ionization and dissociation of molecular ions: its application to CO+Peer reviewedClosed access 

      2006, LECOINTRE, Julien; Belic, D. S.; Cherkani-Hassani, H.; Jureta, J. J.; Defrance, P., HENALLUX
      Article scientifique
      A crossed electron–ion beam experimental set-up has been upgraded for the study of electron impact ionization and dissociation of molecular ions by means of ionic product detection. Both the experimental set-up and the data analysis procedures are described in detail for the estimation of (i) absolute cross sections, (ii) kinetic energy release distributions (KERD) and (iii) anisotropies of angular ...
    • Absolute cross sections and kinetic energy release for doubly and triply charged fragments produced by electron impact on CO+Peer reviewedClosed access 

      2006, LECOINTRE, Julien; Belic, D. S.; Jureta, J. J.; Becker, K.; Deutsch, H.; Limtrakul, J.; Märk, T. D.; Probst, M.; Defrance, P., HENALLUX
      Article scientifique
      Absolute cross sections for electron impact ionization of CO+ leading to the formation of doubly and triply charged products (CO2+, C2+ and O2+, C3+ and O3+) are reported in the energy range from their respective thresholds to 2500 eV. Around the maximum, cross section values are found to be (13.36 ± 0.56) × 10−18 cm2, (5.58 ± 0.55) × 10−18 cm2 and (1.37 ± 0.14) × 10−18 cm2 for CO2+, C2+ and O2+, ...
    • Mass Spectrometric Investigation of Anions Formed upon Free Electron Attachment to Nucleobase Molecules and Clusters Embedded in Superfluid Helium DropletsPeer reviewedClosed access 

      2006, LECOINTRE, Julien; Denifl, S.; Zappa, F.; Mähr, I.; Probst, M.; Märk, T. D.; Scheier, P., HENALLUX
      Article scientifique
      Here we report the first mass spectrometric study of negative ions formed via free electron attachment (EA) to nucleobases (NBs) embedded in helium clusters. Pure and mixed clusters of adenine and thymine have been formed by pickup of isolated NB molecules by cold helium droplets. In contrast to EA of isolated molecules in the gas phase we observe a long-lived parent anion NB− and, in addition, ...
    • Supraconducteurs à haute température : mesure des caractéristiques par impulsions de courantPeer reviewedOpen access 

      2006, Bodesson, Jean-Philippe; LESCROART, Ralph, HENALLUXFoRS
      Article scientifique
      Les limiteurs de courant à supraconducteurs sont des dispositifs qui permettent de limiter, presque instantanément, le courant lorsqu’il y a un court circuit sur une ligne à haute tension. Les supraconducteurs utilisés dans cette application sont des supraconducteurs à haute température. Pour que les limiteurs fonctionnent de manière optimale, il est impératif de bien connaître les valeurs de ...
    • Electron impact ionization of thymine clusters embedded in superfluid helium dropletsPeer reviewedClosed access 

      2007, LECOINTRE, Julien; Zappa, F.; Denifl, S.; Mähr, I.; Rondino, F.; Echt, O.; Märk, T.D.; Scheier, P., HENALLUX
      Article scientifique
      Embedding molecules in helium clusters has become a powerful technique for the preparation of cold targets for spectroscopy experiments, as well as for the assembly of complex, fragile molecular species. We have recently developed a helium cluster source and a pick-up cell to produce neutral beams of doped helium droplets, to be used as targets in studies on electron collisions with molecules of ...
    • Absolute cross sections and kinetic energy release distributions for electron impact ionization and dissociation of CD+Peer reviewedClosed access 

      2007, LECOINTRE, Julien; Cherkani-Hassani, S.; Belic, D. S.; Jureta, J. J.; Becker, K.; Deutsch, H.; Märk, T. D.; Probst, M.; Janev, R. K., HENALLUX
      Article scientifique
      Absolute cross sections for electron impact dissociative excitation and ionization of CD+ leading to the formation of ionic products (D+, C+, C2+ and C3+) are reported in the energy range from their respective thresholds to 2.5 keV. Around the maximum, cross sections are found to be (10.5 ± 1.0) × 10−17 cm2, (20.6 ± 3.5) × 10−17 cm2, (1.20 ± 0.11) × 10−17 cm2 and (8.2 ± 1.5) × 10−20 cm2 for D+, C+, ...
    • Water-molecule dissociation by proton and hydrogen impactPeer reviewedClosed access 

      2007, LECOINTRE, Julien; Luna, H.; de Barros, A. L. F.; Wyer, J. A.; Scully, S. W. J.; Garcia, P. M. Y.; Sigaud, G. M.; Santos, A. C. F.; Senthil, V.; Shah, M. B.; Latimer, C. J.; Montenegro, E. C., HENALLUX
      Article scientifique
      Time-of-flight-based mass analysis of charged water fragments have been used to measure the dissociative and the nondissociative reaction pathways of water formed during collisions with 15 to 100 keV and 500 to 3500 keV H+ projectiles and with 8 to 100 keV H0 projectiles. The fragmentation pathways resulting from the ionization and the electron capture collisions with the incident H+ and H0 ...
    • Water Fragmentation and Energy Loss by Carbon Ions at the Distal Region of the Bragg PeakPeer reviewedClosed access 

      2007, LECOINTRE, Julien; Montenegro, E. C.; Shah, M. B.; Luna, H.; Scully, S. W. J.; de Barros, A. L. F.; Wyer, J. A., HENALLUX
      Article scientifique
      Time-of-flight mass spectrometry was used to investigate fragmentation and energy transfer processes in water by C ions at the distal part of the Bragg peak. Measurements of the positive ion fragments from ionization, electron capture, electron loss, transfer-loss and loss-ionization channels have allowed us for the first time (a) to obtain a quantitative determination of the energy lost by C ions ...
    • Introduction aux nanotechnologiesPeer reviewedOpen access 

      2007, HAVENNE, A.; LESCROART, Ralph, HENALLUXFoRS
      Article scientifique
      Cet article, introduction au « nanomonde », décrit d’abord quelques éléments historiques, puis le fonctionnement du microscope à force atomique qui est l’appareil d’observation des nanostructures. Ensuite, les voies ascendantes et descendantes d’assemblage sont expliquées en détail. Enfin, quelques applications sont présentées, certaines déjà développées dans nos laboratoires, d’autres, encore ...
    • Absolute cross sections and kinetic energy release distributions for electron-impact ionization and dissociation of CD+ 4Peer reviewedClosed access 

      2008, LECOINTRE, Julien; Belic, D. S.; Jureta, J. J.; Janev, R. K.; Defrance, P., HENALLUX
      Article scientifique
      Absolute cross sections for electron-impact dissociative excitation and ionization of CD+ 4 leading to formation of ionic products (CD2+ 4, CD+ 3, CD+ 2, CD+, C+, D+ 3, D+ 2, and D+) have been measured. The animated crossed-beams method is applied in the energy range from the reaction threshold up to 2.5 keV. Around 100 eV, the maximum cross sections are found to be (3.8±0.2) ×10-19 cm2, (10.8±1.5)× ...
    • Screening effects and total cross sections of single, double and triple ionization of neon by fast electronsPeer reviewedClosed access 

      2008, LECOINTRE, Julien; Defrance, P.; Jureta, J.J.; Kereselidze, T.; Machavariani, Z.S., HENALLUX
      Article scientifique
      The Bethe–Born theory is applied to estimate the effective charges experienced by the ejected electrons at single, double and triple ionization of neon by fast electrons. The expansion coefficients appearing in the asymptotic expressions for total cross sections σn+ ~ [an+ln(Ei/In+) + bn+]/Ei are determined by fitting to these expressions the experimental data for single and multiple ionization of ...
    • Absolute cross sections and kinetic energy release distributions for electron-impact dissociative excitation and ionization of NeD+Peer reviewedClosed access 

      2008, LECOINTRE, Julien; Jureta, J.J.; Mitchell, J. B. A.; Ngassam, V.; Orel, A. E.; Defrance, P., HENALLUX
      Article scientifique
      Absolute cross sections for electron impact dissociative excitation and ionization of NeD+ leading to the formation of singly and multiply charged products (D+, Ne+, Ne2+ and Ne3+) are reported, in the energy range from their respective thresholds to 2.5 keV. The animated crossed-beams method is used. For singly charged fragments, absolute cross sections are obtained separately for dissociative ...
    • Electron-impact ionization of singly-charged neon ionsPeer reviewedClosed access 

      2008, LECOINTRE, Julien; Jureta, J.J.; Defrance, P., HENALLUX
      Article scientifique
      Absolute cross sections for electron-impact single and multiple ionization of Ne+ leading to the formation of Neq+ (q = 2–5) are reported. The animated crossed beams method is applied in the energy range from the respective thresholds up to 2.5 keV. The maximum cross sections are found to be (4.12 ± 0.21) × 10−17 cm2, (1.42 ± 0.07) × 1018 cm2, (2.57 ± 0.14) × 10−20 cm2, (8.78 ± 0.54) × 10−22 cm2 for ...