6,324 research outputs found

    A Method to Calculate Fission-Fragment Yields Y(Z,N)Y(Z,N) versus Proton and Neutron Number in the Brownian Shape-Motion Model. Application to calculations of U and Pu charge yields

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    We propose a method to calculate the two-dimensional (2D) fission-fragment yield Y(Z,N)Y(Z,N) versus both proton and neutron number, with inclusion of odd-even staggering effects in both variables. The approach is to use Brownian shape-motion on a macroscopic-microscopic potential-energy surface which, for a particular compound system is calculated versus four shape variables: elongation (quadrupole moment Q2Q_2), neck dd, left nascent fragment spheroidal deformation ϵf1\epsilon_{\rm f1}, right nascent fragment deformation ϵf2\epsilon_{\rm f2} and two asymmetry variables, namely proton and neutron numbers in each of the two fragments. The extension of previous models 1) introduces a method to calculate this generalized potential-energy function and 2) allows the correlated transfer of nucleon pairs in one step, in addition to sequential transfer. In the previous version the potential energy was calculated as a function of ZZ and NN of the compound system and its shape, including the asymmetry of the shape. We outline here how to generalize the model from the "compound-system" model to a model where the emerging fragment proton and neutron numbers also enter, over and above the compound system composition

    Effect of stripe order strength for the Nernst effect in La_{2-x}Sr_xCu_4 single crystals

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    We have precisely measured the Nernst effect in Nd-doped La2−x_{2-x}Srx_xCuO4_4 single crystals with controlling the strength (stability) of the stripe order. We found that the onset temperature TonsetT_{onset}, where the Nernst signal starts increasing, does not change conspicuously in spite of Nd-doping. At low temperatures, on the other hand, the absolute value of the Nernst signal is strongly suppressed in accordance with the strength of the stripe order. These results imply that the fluctuation of (charge) stripe order enhances the Nernst signal below TonsetT_{onset} at high temperatures, and then the stripe order enhanced by Nd-doping suppresses the superconducting fluctuation to reduce the Nernst signal at low temperatures. We also observed an increase of the Nernst signal below the charge order temperature TchT_{ch} which is observed in diffraction measurement.Comment: 3pages, 2figure
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