Search results for "Light nucleus"

Molecular structures inT=1states of10B

2011

Multi-center (molecular) structures can play an important role in light nuclei. The highly deformed rotational band in 10Be with band head at 6.179 MeV has been observed recently and suggested to have an exotic alpha:2n:alpha configuration. A search for states with alpha:pn:alpha two-center molecular configurations in 10B that are analogous to the states with alpha:2n:alpha structure in 10Be has been performed. The T=1 isobaric analog states in 10B were studied in the excitation energy range of E=8.7-12.1 MeV using the reaction 1H(9Be,alpha)6Li*(T=1, 0+, 3.56 MeV). An R-matrix analysis was used to extract parameters for the states observed in the (p,alpha) excitation function. Five T=1 stat…

Efficient synthesis of 2-bromo-1-[18F]fluoroethane and its application in the automated preparation of 18F-fluoroethylated compounds

2002

An efficient synthesis of 2-bromo-1-[18F]fluoroethane from commercially available 1,2-dibromoethane and its integration into an automated preparation device was developed for the routine synthesis of 18F-fluoroethylated compounds. The 1,2-dibromoethane was reacted with the [18F]fluoride/Kryptofix 2.2.2./carbonate complex in acetonitrile at 70 degrees C for 3 min resulting in 60-70% radiochemical yields. The crude reaction mixture was diluted with water, loaded on a LiChrolute EN-cartridge, eluted with acetonitrile and passed through an AluminaB-cartridge. This method provides 2-bromo-1-[18F]fluoroethane with 98% radiochemical purity and <0.1 micromol of 1,2-dibromoethane within 10 min, thus…

Extended Skyrme pseudopotential deduced from infinite nuclear matter properties

2015

We discuss the contributions to the equation of state for the NlLO Skyrme pseudopotential (l = 2,3). We show that by adding fourth- and sixth-order gradient terms, it is possible to fairly reproduce the spin/isospin decomposition of an equation of state obtained from ab initio methods. Moreover, by inspecting the partial-wave decomposition of the equation of state, we show for the first time a possible way to add explicit constraints on the sign of the tensor terms of the Skyrme interaction.

Place de l’imagerie dans l’évaluation de l’efficacité des traitements dans le cancer du sein

2010

Resume Cette revue decrit le role de differentes methodes d’imagerie pour evaluer la reponse au traitement dans le cancer du sein. Deux situations sont envisageables : celle de la chimiotherapie neoadjuvante du cancer du sein et celle des metastases. Beaucoup de donnees cliniques sont disponibles pour trois criteres : le volume de la tumeur, la captation du fluorodeoxyglucose mesuree en TEP et la perfusion de la tumeur evaluee soit par IRM dynamique, soit en TEP. La TEP au 2-18F fluoro-2-desoxy-D-glucose (FDG) permet la prediction de la reponse apres une ou deux cures de chimiotherapie. De nouvelles approches pourraient prochainement affiner le role de l’imagerie. Ainsi, la TEP a la thymidi…

Shell-model study of partial muon-capture rates in light nuclei

1998

Abstract The nuclear shell model is used to study ordinary muon capture of light nuclei in the p, sd and p-sd shell-model spaces. Several well-established two-body interactions are applied to calculate the involved nuclear matrix elements and the emerging results are compared with each other. The resulting theoretical partial muon-capture rates are compared with experimental data and their stability against different model spaces and interactions studied. The effects of the induced-pseudoscalar strength, C p , on the capture rates is discussed. The relation between the allowed partial muon capture rates and the Gamow-Teller strength function is stressed.

Commissioning of the vacuum system of the KATRIN Main Spectrometer

2016

The KATRIN experiment will probe the neutrino mass by measuring the β-electron energy spectrum near the endpoint of tritium β-decay. An integral energy analysis will be performed by an electro-static spectrometer (``Main Spectrometer''), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m[superscript 3], and a complex inner electrode system with about 120 000 individual parts. The strong magnetic field that guides the β-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips ha…

LiquidHe4andHe3at negative pressure

1992

The critical pressures {ital P}{sub {ital c}} at which liquid {sup 4}He and {sup 3}He each become macroscopically unstable are determined from two kinds of microscopic calculations that reproduce the equation of state. The behavior of the sound velocity {ital c} around this critical pressure is analyzed, and the critical exponent in {ital c}{proportional to}({ital P}{minus}{ital P}{sub {ital c}}){sup {nu}} is found to be {nu}=1/4. A comparison with empirical analysis is also done.

Electromagnetic sum rules for light nuclei

2008

Electromagnetic sum rules describe gross features of the electromagnetic structure of nuclei 1). A well known example is the Thomas-Reiche-Kuhn (TRK) sum rule, which relates the integrated total El-absorption cross section to the ground state expectation value of the double commutator of the dipole operator D with the nuclear Hamiltonian. While the k inet ic energy gives a model independent contr ibut ion, i . e . , the classical sum rule ~cl = 60 NZ/A MeV mb, the nuclear twobody potential gives an additional contr ibution in the presence of exchange and/or momentum dependent (or nonlocal) forces. In this case, I

Proterozoic dykes of Salvador and Ilhéus-Olivença areas: a geological geoghemical comparison

1991

Total cross sections of reactions induced by neutron-rich light nuclei

1989

Total nuclear reaction cross-sections are determined by means of a 4π-γ method. The results cover a wide span of targets for various stable beams. The validity of the method is shown in a combined systematics including also the results of transmission-type experiments. The data are very well described by the formula developed by Kox et al. The same method is applied to secondary fragment beams produced from a 44 MeV/u22Ne beam on a 332mg/cm2 181Ta target. Using the LISE spectrometer the fragments4, 6He,6–9, 11Li,7, 9–12, 14Be,10–15, 17B11–19C,13–19N,15–21O,18– 21F and20,21 Ne are analyzed and transported to interact with a 199.4 mg/cm2 Cu target surrounded by a 4π-γ counter. The measured to…