12 research outputs found

    A mask for high-intensity heavy-ion beams in the MAYA active target

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    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a 136Xe beam are presented.status: publishe

    High-precision half-life measurement for the isospin T=1/2 mirror beta(+) decay of Na-21

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    The half-life of the isospin T=1/2 mirror ÎČ+ decay of 21Na was measured at the GANIL-SPIRAL radioactive ion beam facility to be T1/2=22.422 (10) s, a result that is more than a factor of 5 times more precise than the previous world average, with a resulting ft value that is now two times more precise. The precision of this new result implies that the half-life is no longer the dominant source of uncertainty in the Ft value used in the calculation of Vud from mirror decays to test the conserved vector current hypothesis of the standard model. The value of Vud deduced from mirror decays using the new half-life result is now in better agreement with the Vud derived from T=1 superallowed 0+ to 0+ transitions.status: publishe

    Distribution and damage associated with the onion thrips, Thrips tabaci L. (Thysanoptera: Thripidae) according to the agro-climatic zone in Burkina Faso

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    RESUME L’oignon est le premier lĂ©gume produit au Burkina Faso. Thrips tabaci constitue son principal insecte ravageur. Ce travail avait pour objectif d’évaluer la distribution, l’incidence et la sĂ©vĂ©ritĂ© des attaques de T. tabaci sur l’oignon. L’étude a Ă©tĂ© rĂ©alisĂ©e dans trois bassins de production reprĂ©sentatifs de deux zones agroĂ©cologiques du Burkina Faso : la zone sahĂ©lienne caractĂ©risĂ©e par une pluviositĂ© moyenne annuelle infĂ©rieure Ă  600 mm et une tempĂ©rature moyenne annuelle de 35 °C ; contre une pluviositĂ© moyenne annuelle comprise entre 600 et 900 mm et une tempĂ©rature moyenne annuelle de 33 °C pour la zone nord soudanienne Nous avons rĂ©alisĂ© des prospections dans 45 parcelles paysannes dans les zones de production ciblĂ©es. Des plantes d’oignon ont Ă©tĂ© prĂ©levĂ©es dans trois quadrats posĂ©s sur une des diagonales de chaque parcelle, et les thrips trouvĂ©s sur chaque plante de chaque quadrat comptĂ©s. Tous les plants Ă  l’intĂ©rieur du quadrat ont Ă©tĂ© donc observĂ©s. La densitĂ© moyenne la plus Ă©levĂ©e (216 ±385 thrips au m2) a Ă©tĂ© observĂ©e dans la rĂ©gion du Nord tandis que l’incidence moyenne la plus Ă©levĂ©e (95,91±8,92%) a Ă©tĂ© observĂ©e dans la Boucle du Mouhoun. La plus faible sĂ©vĂ©ritĂ© (19,29±13,27%) a Ă©tĂ© enregistrĂ©e dans le Plateau central. Cette Ă©tude est un premier pas vers le dĂ©veloppement de stratĂ©gies alternatives de lutte contre les parasites dans le cadre de systĂšmes de production vĂ©gĂ©tale durables Ă  l’aide de bonnes pratiques agricoles et de l’utilisation des pesticides biologiques. © 2020 International Formulae Group. All rights reserved.Production durable intĂ©grant la recherch

    A new FEBIAD-type ion source for the upgrade of SPIRAL1 at GANIL

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    The SPIRAL facility at GANIL is being upgraded with a new FEBIAD ion source in order to extend its production capabilities to condensable elements. The coupling of such an ion source with the present GANIL target was recently tested online at SPIRAL at nominal power (1200 W). The results are promising as the calculated yields are in the range of those extrapolated from previous measurements at lower power and sometimes higher. This experiment and its results are presented.status: publishe

    First inverse-kinematics fission measurements in a gaseous active target

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    The fission of a variety of actinides was induced by fusion and transfer reactions between a 238U beam and 12C nuclei, in the active target MAYA. The performance of MAYA was studied, as well as its capability to reconstruct the fission-fragment trajectories. Furthermore, a full characterization of the different transfer reactions was achieved, and the populated excitation-energy distributions were investigated as a function of the kinetic energy in the entrance channel. The ratio between transfer- and fusion-induced fission cross-sections was also determined, in order to investigate the competition between both reaction types and its evolution with the incident energy. The experimental results will be discussed with a view to forthcoming radioactive-ion beam facilities, and next-generation active-target setups.status: publishe
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