126 research outputs found

    Soil loss prediction using universal soil loss equation (USLE) simulation model in a mountainous area in Aglasun district, Turkey

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    Land degradation and soil loss is a global event. Human induced pressures on the natural ecosystems are still in progress as well as conservation efforts. The need for sufficient knowledge and data for decision makers is obvious hence the present study was carried out. The study area, the Alasun district, is in the middle west of Turkey and is characterized by a cold and sub-humid Mediterranean climate. The mountainous area is mostly covered with average low canopy closure of 11 - 40% of different forest species (52% of the study area). Universal soil loss equation (USLE) simulation model was used to predict the soil loss amounts in the study area. The results show that the predicted average soil loss amount is 7.38 (ton/ha/year). The average soil depth is about 35 cm and the soil loss tolerance limit is widely exceeded in the study area

    One-neutron transfer reaction in the 18^{18}O + 48^{48}Ti collision at 275 MeV

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    The present article reports new data on the 48^{48}Ti(18^{18}O,17^{17}O)49^{49}Ti reaction at 275 MeV incident energy as part of the systematic research pursued within the NUMEN project. Supplementary measurements of the same reaction on 16^{16}O and 27^{27}Al targets were also performed in order to estimate the background arising from the use of a composite target (TiO2_{2} + 27^{27}Al). These data were analyzed under the same theoretical framework as those obtained with the titanium target in order to reinforce the conclusions of our analysis. Differential cross-section angular distribution measurements for the 17^{17}O8+^{8+} ejectiles were performed in a wide angular range by using the MAGNEX large acceptance magnetic spectrometer. The experimental results were analyzed within the distorted-wave and coupled-channels Born Approximation frameworks. The optical potentials at the entrance and exit channels were calculated in a double folding approach adopting the S\~ao Paulo potential, and the spectroscopic amplitudes for the projectile and target overlaps were obtained from large-scale shell model calculations. The differential cross-sections are well-described by the theoretical calculations, where a weak coupling to collective excitations of projectile and target is inferred. The sensitivity of transfer cross-sections on different model spaces adopted in nuclear structure calculations, is also discussed

    Background estimate in heavy-ion two-body reactions measured by the MAGNEX spectrometer

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    The MAGNEX magnetic spectrometer is nowadays used in the experimental measurements of rare quasi-elastic reactions between heavy ions at intermediate energy within the NUMEN project. The small cross sections involved in such processes under the large yields due to competitive reaction channels have motivated an accurate control of the background sources. In such view, the not ideal particle identification could introduce spurious contributions which have been identified and evaluated in the present analysis

    One-proton transfer reaction for the O 18 + Ti 48 system at 275 MeV

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    Single-nucleon transfer reactions are processes that selectively probe single-particle components of the populated many-body nuclear states. In this context, recent efforts have been made to build a unified description of the rich nuclear spectroscopy accessible in heavy-ion collisions. An example of this multichannel approach is the study of the competition between successive nucleon transfer and charge exchange reactions, the latter being of particular interest in the context of single and double beta decay studies. To this extent, the one-proton pickup reaction Ti48(O18,F19)Sc47 at 275 MeV was measured for the first time, under the NUMEN experimental campaign. Differential cross-section angular distribution measurements for the F19 ejectiles were performed at INFN-LNS in Catania by using the MAGNEX large acceptance magnetic spectrometer. The data were analyzed within the distorted-wave and coupled-channels Born approximation frameworks. The initial and final-state interactions were described adopting the SĂŁo Paulo potential, whereas the spectroscopic amplitudes for the projectile and target overlaps were derived from shell-model calculations. The theoretical cross sections are found to be in very good agreement with the experimental data, suggesting the validity of the optical potentials and the shell-model description of the involved nuclear states within the adopted model space

    A constrained analysis of the 40Ca(18O,18F)40K direct charge exchange reaction mechanism at 275 Mev

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    The40 Ca(18 O,18 F)40 K single charge exchange (SCE) reaction is explored at an incident energy of 275 MeV and analyzed consistently by collecting the elastic scattering and inelastic scattering data under the same experimental conditions. Full quantum-mechanical SCE calculations of the direct mechanism are performed by including microscopic nuclear structure inputs and adopting either a bare optical potential or a coupled channel equivalent polarization potential (CCEP) constrained by the elastic and inelastic data. The direct SCE mechanism describes the magnitude and shape of the angular distributions rather well, thus suggesting the suppression of sequential multi-nucleon transfer processes

    The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay

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    The article describes the main achievements of the NUMEN project togetherwith an updated and detailed overview of the related R&D activities andtheoretical developments. NUMEN proposes an innovative technique to access thenuclear matrix elements entering the expression of the lifetime of the doublebeta decay by cross section measurements of heavy-ion induced Double ChargeExchange (DCE) reactions. Despite the two processes, namely neutrinoless doublebeta decay and DCE reactions, are triggered by the weak and strong interactionrespectively, important analogies are suggested. The basic point is thecoincidence of the initial and final state many-body wave-functions in the twotypes of processes and the formal similarity of the transition operators. Firstexperimental results obtained at the INFN-LNS laboratory for the40Ca(18O,18Ne)40Ar reaction at 270 MeV, give encouraging indication on thecapability of the proposed technique to access relevant quantitativeinformation. The two major aspects for this project are the K800Superconducting Cyclotron and MAGNEX spectrometer. The former is used for theacceleration of the required high resolution and low emittance heavy ion beamsand the latter is the large acceptance magnetic spectrometer for the detectionof the ejectiles. The use of the high-order trajectory reconstructiontechnique, implemented in MAGNEX, allows to reach the experimental resolutionand sensitivity required for the accurate measurement of the DCE cross sectionsat forward angles. However, the tiny values of such cross sections and theresolution requirements demand beam intensities much larger than manageablewith the present facility. The on-going upgrade of the INFN-LNS facilities inthis perspective is part of the NUMEN project and will be discussed in thearticle

    Recent results on heavy-ion induced reactions of interest for neutrinoless double beta decay at INFN-LNS

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    Abstract. The possibility to use a special class of heavy-ion induced direct reactions, such as double charge exchange reactions, is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay halflife. The methodology of the experimental campaign presently running at INFN - Laboratori Nazionali del Sud is reported and the experimental challenges characterizing such activity are describe

    A focus on selected perspectives of the NUMEN project

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    The use of double charge exchange reactions is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay half-life. The strategy adopted in the experimental campaigns performed at INFN - Laboratori Nazionali del Sud and in the analysis methods within the NUMEN project is briefly described, emphasizing the advantages of the multi-channel approach to nuclear reaction data analysis. An overview on the research and development activities on the MAGNEX magnetic spectrometer is also given, with a focus on the chosen technological solutions for the focal plane detector which will guarantee the performances at high-rate conditions
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