• N L Singh

      Articles written in Pramana – Journal of Physics

    • Mathematical analysis of isobaric decay chain in alpha particle induced reactions

      S Mukherjee N L Singh J Rama Rao

      More Details Abstract Fulltext PDF

      A detailed mathematical formalism is developed from the first principles, to separate out the fractional contributions of the cross-sectionσg andσp for the production of the two isobaric precursor nuclei- grand parent and parent, respectively, to the cross-sectionσd for the formulation of the residual nucleus of interest. The analytical work of separating out such contributions gives a meaningful picture to the comparison with the theoretical predictions of hybrid model, using the initial excition numbern0 = 4(4p0h).

    • Analysis of the excitation functions of (α, xnyp) reactions on natural copper

      N L Singh B J Patel D R S Somayajulu S N Chintalapudi

      More Details Abstract Fulltext PDF

      Excitation functions of the reactions63Cu[(α, n), (α, 2n)+(α, pn)] and65Cu[(α, n), (α, 2n), (α, 3n), (α, 4n)+(α, p3n)] were investigated up to 50 MeV using stacked foil activation technique and Ge(Li) gamma ray spectroscopy method. Since natural copper used as the target has two odd-mass stable isotopes of abundance,63Cu(69.17%) and65Cu(30.83%), their activation in some cases, gives the same residual nucleus through different reaction channels but with very different threshold energies. In such cases, the individual reaction cross sections are separated with the ratio of theoretical cross sections. The experimental results were compared with the predictions of preequilibrium hybrid model of Blann. A general agreement was found in all reactions using initial exciton numbern0=4(4p0h) and also preequilibrium fraction depends on the incident particle energy.

    • Measurement and analysis of alpha particle induced reactions on gold

      D J Shah H B Patel N L Singh S Mukherjee S N Chintalapudi

      More Details Abstract Fulltext PDF

      Stacked foil activation technique and Ge(Li) gamma ray spectroscopy have been used for the measurement of excitation functions of197Au(α,xn) (x=1−3),197Au(α,2pn) and197Au(α,αn) reactions up to 50 MeV. The experimental cross-sections were compared with the predictions of pre-equilibrium hybrid model, as well as with the more recent index model. A general agreement was found in all reactions using initial exciton numbern0=4(4p0h) except for197Au(α,n) reaction, where index model gives fairly good agreement withn0=5(5p0h).

    • Excitation functions of alpha particle induced reactions on aluminium and copper

      S Mukherjee B Bindu Kumar N L Singh

      More Details Abstract Fulltext PDF

      Cross-sections for the reactions with product nuclei24Na,22Na,68Ga and67Ga were investigated over the energy range of 30 to 75 MeV for alpha particle induced reactions on natural aluminium and copper, using stacked-foil activation technique. The measured excitation functions were analysed with special reference to their suitability for monitoring beam energy and intensity. The experimental results were compared with the predictions of hybrid model of Blann. The assumption of initial exciton numbern0=4(4p0h) best satisfies the measured excitation functions in the present work.

  • Pramana – Journal of Physics | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2017-2019 Indian Academy of Sciences, Bengaluru.