New aspects of nuclear physics with heavy ion beams delivered by cyclotrons

http://accelconf.web.cern.ch/AccelConf/c81/papers/gi-01.pdfInternational audienc

L'UTILISATION DES FAISCEAUX D'IONS LOURDS, "NOUVELLE" ou "VIEILLE" PHYSIQUE NUCLEAIRE ?

Quelques aspects nouveaux et originaux apportés à la physique nucléaire par les ions lourds sont présentés. Du point de vue des techniques expérimentales, ce sont les faisceaux, les méthodes d'identification de masse et de Z, les coïncidences multiples et les collections de noyaux. Du point de vue de la connaissance en physique nucléaire, c'est une compréhension d'un micro-ensemble de matière condensée. On décrit les grandes lignes des réactions qualifiées de "dissipatives" et les aspects de mécanique statistique appliquée au fluide nucléaire, ainsi que l'estimation de la durée des phénomènes. On montre ensuite comment les idées de base "anciennes" de la physique du début du siècle sont fertiles pour décrire macroscopiquement les noyaux

HICOFED OUTLOOK

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GANIL

The project Ganil which is under construction at Caen consists essentially of two identical isochronous separated sector cyclotrons with K = 400. The principle of the accelerator and the expected performances are presented

Réactions nucléaires provoquées par ions « lourds ». Intérêt et divers aspects

A survey is given of nuclear phenomena induced by multicharged heavy ions. Several features are discussed : reactions involving a fusion nucleus, " buckshot " reactions in which heavy ions are broken into several fragments in the vicinity of target nuclides, disintegration stars and transfer reactions. The usefulness of heavy ion reactions for measuring fission width and Γn/Γ f ratios, is emphasized. Also the production of neutron deficient nuclides and of transuranium elements is discussed.Les phénomènes nucléaires provoqués par les ions multichargés d'énergie élevée sont examinés sous leurs différents aspects : réactions passant par un noyau de fusion, réactions de multi-stripping aux cours desquelles l'ion lourd se sépare en plusieurs projectiles aux abords du noyau cible, étoiles de désintégration et réactions de transfert d'un nucléon entre le noyau projectile et le noyau cible. On indique aussi comment les ions lourds sont utilisés pour mesurer les probabilités de fission, les rapports Γn/Γ f de noyaux lourds très excités. Enfin, la production de noyaux déficients en neutrons et d'éléments transuraniens est envisagée

Range of orbital angular momenta available for complete fusion between heavy ions

The same compound nucleus, 158Er, has been formed through three different entrance channels, with projectiles 16O, 40Ar and 84Kr. Excitation functions for reactions (HI, 5n) and (HI, 6n) are well fitted by statistical model calculations, provided that a certain window in orbital angular momentum should be taken in order to produce complete fusion in the case of Ar ions and Kr ions. Curiously enough, low l-waves should be avoided. It implies that, during the interaction leading to complete fusion, the energy dissipation by tangential friction should be rather large

Multi-wavelength, all-solid-state, continuous wave mode locked picosecond Raman laser

We demonstrate the operation of a cascaded continuous wave (CW) mode-locked Raman oscillator. The output pulses were compressed from 28 ps at 532 nm down to 6.5 ps at 559 nm (first Stokes) and 5.5 ps at 589 nm (second Stokes). The maximum output was 2.5 W at 559 nm and 1.4 W at 589 nm with slope efficiencies up to 52%. This technique allows simple and efficient generation of short-pulse radiation to the cascaded Stokes wavelengths, extending the mode-locked operation of Raman lasers to a wider range of visible wavelengths between 500 - 650 nm based on standard inexpensive picosecond Nd:YAG oscillators

Ecological and pest-management implications of sex differences in scarab landing patterns on grape vines

Background: Melolonthinae beetles, comprising different white grub species, are a globally-distributed pest group. Their larvae feed on roots of several crop and forestry species, and adults can cause severe defoliation. In New Zealand, the endemic scarab pest Costelytra zealandica (White) causes severe defoliation on different horticultural crops, including grape vines (Vitis vinifera). Understanding flight and landing behaviours of this pest can help inform pest management decisions. Methods: Adult beetles were counted and then removed from 96 grape vine plants from 21:30 until 23:00 h, every day from October 26 until December 2, during 2014 and 2015. Also, adults were removed from the grape vine foliage at dusk 5, 10, 15, 20 and 25 min after flight started on 2015. Statistical analyses were performed using generalised linear models with a beta-binomial distribution to analyse proportions and with a negative binomial distribution for beetle abundance. Results: By analysing C. zealandica sex ratios during its entire flight season, it is clear that the proportion of males is higher at the beginning of the season, gradually declining towards its end. When adults were successively removed from the grape vines at 5-min intervals after flight activity begun, the mean proportion of males ranged from 6-28%. The male proportion suggests males were attracted to females that had already landed on grape vines, probably through pheromone release. Discussion: The seasonal and daily changes in adult C. zealandica sex ratio throughout its flight season are presented for the first time. Although seasonal changes in sex ratio have been reported for other melolonthines, changes during their daily flight activity have not been analysed so far. Sex-ratio changes can have important consequences for the management of this pest species, and possibly for other melolonthines, as it has been previously suggested that C. zealandica females land on plants that produce a silhouette against the sky. Therefore, long-term management might evaluate the effect of different plant heights and architecture on female melolonthine landing patterns, with consequences for male distribution, and subsequently overall damage within horticultural areas