62 research outputs found

    Dealkylation of alkyl polycyclic aromatic hydrocarbon over silica monolayer solid acid catalyst

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    Dealkylation of alkylnaphthalene, as a model of alkyl polycyclic aromatic hydrocarbon compounds in heavy oils, proceeded selectively on a silica monolayer solid acid catalyst. The activity was generated by the deposition of silica on alumina with generation of Brønsted acidity. The activity and Brønsted acid amount showed the maximum where the monolayer covered the surface, indicating that the Brønsted acid site generated on the silica monolayer was the active species. The activity and selectivity on the silica monolayer were high compared to other aluminosilicate catalysts, and high activity was observed even after calcination at 973–1173K

    Double differential cross section for light mass fragment production on tens of MeV proton, deuteron, helium and carbon induced reactions

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    Double differential cross sections (DDXs) of light mass fragment (LMFs - Li,Be,B,C,N and O) productions were measured for tens of MeV proton, deuteron helium and carbon induced reactions on Be, C, Al, Ti and Cu targets. The incident energies for the measurements were chosen to allow us to compare DDXs with same incident energy but different projectiles on various targets. Systematic data were obtained to see the differences between projectile energies, particles, targets and emitted particles. From the comparison, reaction processes of not only evaporation from complete fusion nucleus, but also scattering, pickup, stripping and projectile fragmentation were observed

    Double-differential cross section measurement with low threshold detector for proton production induced by several tens of MeV protons

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    We have developed a low threshold detector consisting of Bragg curve counter (BCC), two siliconsurface barrier detectors (SSDs) and BGO scintillator to obtain experimental double-differential cross section (DDX) data for low energy proton production. Since the BCC offers advantage of self particle identification capability and a few μm-thick entrance window, protons produced by nuclear reactions down to 1 MeV have been identified. The capability of the detector is demonstrated in measurements using 70-MeV protons. Measured spectra are compared with calculation results of intra-nuclear cascade (INC) plus evaporation models and nuclear data library

    Double-differential cross section measurement with low threshold detector for proton production induced by several tens of MeV protons

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    We have developed a low threshold detector consisting of Bragg curve counter (BCC), two siliconsurface barrier detectors (SSDs) and BGO scintillator to obtain experimental double-differential cross section (DDX) data for low energy proton production. Since the BCC offers advantage of self particle identification capability and a few μm-thick entrance window, protons produced by nuclear reactions down to 1 MeV have been identified. The capability of the detector is demonstrated in measurements using 70-MeV protons. Measured spectra are compared with calculation results of intra-nuclear cascade (INC) plus evaporation models and nuclear data library

    Spectrum Measurement Down to 1 MeV/u Particles with Hydrogen-Identification Using Bragg Curve Counter

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    We have developed a low threshold detector consisting of Bragg curve counter (BCC) and two built-in solid-state detectors (SSDs) to measure spectra of low energy charged particles emitted by nuclear reactions. Since the BCC, ionization chamber offers advantages of self particle identification capability and a few m-thick entrance window, the threshold energy less than 1 MeV/u is expected with particle identification. The detector is tested using 70 MeV protons for measurement of double-differential cross sections (DDXs) of charged particle production. Protons produced down to 1 MeV have been identified and resultant DXs for proton production have been obtained down to 1.5 MeV

    Double differential cross section for light mass fragment production on tens of MeV proton, deuteron, helium and carbon induced reactions

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    The Authors, published by EDP Sciences, 2017. Double differential cross sections (DDXs) of light mass fragment (LMFs - Li,Be,B,C,N and O) productions were measured for tens of MeV proton, deuteron helium and carbon induced reactions on Be, C, Al, Ti and Cu targets. The incident energies for the measurements were chosen to allow us to compare DDXs with same incident energy but different projectiles on various targets. Systematic data were obtained to see the differences between projectile energies, particles, targets and emitted particles. From the comparison, reaction processes of not only evaporation from complete fusion nucleus, but also scattering, pickup, stripping and projectile fragmentation were observed

    Angular distribution of evaporated protons from 50-MeV-range proton-nucleus reactions

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    The angular distribution of compound reactions at bombarding energies lower than 10 MeV is known to be 90˚ symmetry. At the higher incident energies, 50-MeV range, the quantization axis tilts from the beam axis due to the particle emission in the cascade or the pre-equilibrium process. Therefore, it is necessary to know the tilted quantization axis for the angular distribution calculation of the evaporated protons from (p, p’x) reactions. In the present work, we applied the intranuclear cascade (INC) model to determine the tilted quantization axis by a classical vector analysis. The proton evaporation was calculated by the generalized evaporation model (GEM). By fitting calculations to experimental angular distributions, we deduced the angular momentum transfer from the equilibrium state

    Double differential cross section for light mass fragment production on tens of MeV proton, deuteron, helium and carbon induced reactions

    No full text
    Double differential cross sections (DDXs) of light mass fragment (LMFs - Li,Be,B,C,N and O) productions were measured for tens of MeV proton, deuteron helium and carbon induced reactions on Be, C, Al, Ti and Cu targets. The incident energies for the measurements were chosen to allow us to compare DDXs with same incident energy but different projectiles on various targets. Systematic data were obtained to see the differences between projectile energies, particles, targets and emitted particles. From the comparison, reaction processes of not only evaporation from complete fusion nucleus, but also scattering, pickup, stripping and projectile fragmentation were observed
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