The role of 14 MeV neutrons in light element nucleosynthesis

The 14 MeV neutron induced nuclear reactions which might contribute to better understanding of so-called “cosmological lithium problem” have been discussed. The BBN theory predicted 7Li overestimated value could be lowered by 2n induced reactions on Li-isotopes and/or 7Be destruction via resonance in d+7Be→9B process. Proposals for 6Li+2n and 7Li+2n reactions cross section evaluations and measurements are discussed in some details. We discuss also a preliminary measurements of n-n coincidences from the 10B(n,2n)9B reaction with two neutron detectors placed outside the cone of 14 MeV tagged neutron beam. From the time-of-flight measurements and known geometry we deduce the neutron energies and calculate the 9B missing mass spectrum

Analysis of carbon soil content by using tagged neutron activation

Here we describe a prototype for non-destructive, in-situ, accurate and cost-effectively measurement procedure of carbon in soil based on neutron activation analysis using 14 MeV tagged neutron beam. This technology can be used for carbon baseline assessment on regional scale and for monitoring of its surface and depth storage due to the changes in agricultural practices undertaken in order to mitigate global climate change. © 2012 SPIE

The role of 14 MeV neutrons in light element nucleosynthesis

The 14 MeV neutron induced nuclear reactions which might contribute to better understanding of so-called “cosmological lithium problem” have been discussed. The BBN theory predicted 7Li overestimated value could be lowered by 2n induced reactions on Li-isotopes and/or 7Be destruction via resonance in d+7Be→9B process. Proposals for 6Li+2n and 7Li+2n reactions cross section evaluations and measurements are discussed in some details. We discuss also a preliminary measurements of n-n coincidences from the 10B(n,2n)9B reaction with two neutron detectors placed outside the cone of 14 MeV tagged neutron beam. From the time-of-flight measurements and known geometry we deduce the neutron energies and calculate the 9B missing mass spectrum

Analysis of carbon soil content by using tagged neutron activation

Here we describe a prototype for non-destructive, in-situ, accurate and cost-effectively measurement procedure of carbon in soil based on neutron activation analysis using 14 MeV tagged neutron beam. This technology can be used for carbon baseline assessment on regional scale and for monitoring of its surface and depth storage due to the changes in agricultural practices undertaken in order to mitigate global climate change. © 2012 SPIE

Red mud characterization using nuclear analytical techniques

Red mud is a toxic waste left as a byproduct in aluminum production Bayer process. Since it contains significant concentrations of other chemical elements interesting for industry, including REE, it is also potential secondary ore source. Recent events in some countries have shown that red mud presents a serious environmental hazard if not properly stored. The subject of our study is the red mud from an ex-aluminum plant in Obrovac, Croatia, left from processing of bauxite mined during late 70's and early 80's at the eastern Adriatic coast and since than stored in open concrete basins for more than 30 years. We have used energy dispersive x-ray fluorescence analysis (both tube and radioactive source excitation), fast neutron activation analysis and passive gamma spectrometry to identify a number of elements present in the red mud, their concentration levels and radioactivity in the red mud. The high concentrations of Al, Si, Ca, Ti and Fe have been measured. Chemical elements Sc, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Br, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Pb, Th and U were found in lower concentrations. No significant levels of radioactivity have been measured. © 2011 IEEE

Red mud characterization using atomic and nuclear analytical techniques

Red mud is a toxic waste left as a byproduct in aluminum production Bayer process. Since it contains significant concentrations of other chemical elements interesting for industry, including Rare Earths Elements (REEs), it is also potential secondary ore source. Recent events in some countries have shown that red mud presents a serious environmental hazard if not properly stored. The subject of our study is evaluation of the red mud elemental composition, especially yttrium, scandium, gallium and REEs, from an ex-aluminum plant in Obrovac, Croatia, left from the processing of bauxite mined during late 70's and early 80's at the eastern Adriatic coast and stored in open concrete basins for more than 30 years since then. © 2012 IEEE

Red mud characterization using atomic and nuclear analytical techniques

Red mud is a toxic waste left as a byproduct in aluminum production Bayer process. Since it contains significant concentrations of other chemical elements interesting for industry, including Rare Earths Elements (REEs), it is also potential secondary ore source. Recent events in some countries have shown that red mud presents a serious environmental hazard if not properly stored. The subject of our study is evaluation of the red mud elemental composition, especially yttrium, scandium, gallium and REEs, from an ex-aluminum plant in Obrovac, Croatia, left from the processing of bauxite mined during late 70's and early 80's at the eastern Adriatic coast and stored in open concrete basins for more than 30 years since then. © 2012 IEEE

Red mud characterization using nuclear analytical techniques

Red mud is a toxic waste left as a byproduct in aluminum production Bayer process. Since it contains significant concentrations of other chemical elements interesting for industry, including REE, it is also potential secondary ore source. Recent events in some countries have shown that red mud presents a serious environmental hazard if not properly stored. The subject of our study is the red mud from an ex-aluminum plant in Obrovac, Croatia, left from processing of bauxite mined during late 70's and early 80's at the eastern Adriatic coast and since than stored in open concrete basins for more than 30 years. We have used energy dispersive x-ray fluorescence analysis (both tube and radioactive source excitation), fast neutron activation analysis and passive gamma spectrometry to identify a number of elements present in the red mud, their concentration levels and radioactivity in the red mud. The high concentrations of Al, Si, Ca, Ti and Fe have been measured. Chemical elements Sc, Cr, Mn, Co, Ni, Cu, Zn, Ga, As, Se, Br, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Pb, Th and U were found in lower concentrations. No significant levels of radioactivity have been measured. © 2011 IEEE