21 research outputs found

    An above-barrier narrow resonance in F-15

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    Intense and purified radioactive beam of post-accelerated O-14 was used to study the low-lying states in the unbound F-15 nucleus. Exploiting resonant elastic scattering in inverse kinematics with a thick target, the second excited state, a resonance at E-R = 4.757(6)(10) MeV with a width of Gamma = 36(5)(14) keV was measured for the first time with high precision. The structure of this narrow above-barrier state in a nucleus located two neutrons beyond the proton drip line was investigated using the Gamow Shell Model in the coupled channel representation with a C-12 core and three valence protons. It is found that it is an almost pure wave function of two quasi-bound protons in the 2s(1/2) shell. (C) 2016 The Authors. Published by Elsevier B.V

    Toward the limit of nuclear binding on the N=Z line : Spectroscopy of Cd 96

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    A γ-decaying isomeric state (τ1/2=197-17+19 ns) has been identified in Cd96, which is one α particle away from the last known bound N=Z nucleus, Sn100. Comparison of the results with shell-model calculations has allowed a tentative experimental level scheme to be deduced and the isomer to be interpreted as a medium-spin negative-parity spin trap based on the coupling of isoscalar (T=0) and isovector (T=1) neutron-proton pairs. The data also suggest evidence for the population of a 9+ T=1 state, which is predicted by shell-model calculations to be yrast. Such a low-lying T=1 state, which is unknown in lighter mass even-even self-conjugate nuclei, can also be interpreted in terms of the coupling of T=0 and T=1 neutron-proton pairs

    Narrow resonances in the continuum of the unbound nucleus 15^{15}F

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    The structure of the unbound 15^{15}F nucleus is investigated using the inverse kinematics resonant scattering of a radioactive 14^{14}O beam impinging on a CH2_2 target. The analysis of 1^{1}H(14^{14}O,p)14^{14}O and 1^{1}H(14^{14}O,2p)13^{13}N reactions allowed the confirmation of the previously observed narrow 1/21/2^{-} resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2^{-} and 3/2^{-} resonances. The newly observed levels decay by 1p emission to the ground of 14^{14}O, and by sequential 2p emission to the ground state (g.s.) of 13^{13}N via the 11^- resonance of 14^{14}O. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2^{-} and 3/2^{-} resonances may be collectivized by the continuum coupling to nearby 2p- and 1p- decay channels. The observed excitation function 1^{1}H(14^{14}O,p)14^{14}O and resonance spectrum in 15^{15}F are well reproduced in the unified framework of the GSM

    Ground surface deformation of the urban area in complex engineering-geological conditions in the sinking town of Tuzla (Bosnia and Herzegovina)

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    deformation of the ground surface and buildings in the town of Tuzla. The southern edge of the deposit dips beneath the northern part of the town. Although relatively small size, the deposit represents an extremely complex geological body The slow, natural processes of dissolution of the deposit's eastern part were accelerated by industrial exploitation of saline water (brine) that lasted over 100 years. Exploitation of the western part of the deposit started much later in 1967, by classical dry underground mining. Natural processes and applied exploitation works endangered part of the town above the deposit. Subsidence has reached its peak in 70-s of the last century, when the city lost huge number of its residential, commercial and cultural facilities. Although the salt exploitation ended (2004 and 2007) very complex processes of degradation of wider deposit environment and urban areas are still ongoing, with visible consequences on the ground surface. Featured are the geodynamic phenomena and deformation caused by a complex structural-tectonic structure of the terrain. Analyzed were also geodetic monitoring data for the period 1956-2010 which present important information about the processes of ground surface movements. Deformation on the ground surface is being developed under the influence of various factors. In the part of the town that was investigated and presented in this paper, the consequences of the salt deposit exploitation on the ground surface are predisposed by complex terrain structure

    Horizontal movements of the ground surface in the zone of influence of salt exploitation in Tuzla (Bosna and Herzegovina)

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    This paper focuses on surface movements determined by geodetic methods and occurred as consequence of brine extraction from Tuzla salt deposit (Bosnia and Herzegovina). Previous studies were mainly focalized on vertical movements, but important information about behavior of the deposit is also available from horizontal movement data. In the case of Tuzla salt deposit the geometry and spatial location of leached/empty spaces are unknown and the comparative analysis of vertical and horizontal movement could be really significant. The spatial identification of points with high values of vertical and horizontal movements depends on the geometry of empty spaces. Horizontal movements investigation has been carried out analyzing data collected by several geodetic measurements. The results obtained by the correlated spatial analysis of vertical and horizontal movements, can identify basic geometric characteristics of the leached/empty spaces. The discussed temporal intervals are two characteristic periods, referred to the capacity of the deposit exploitation. Movement rates per year and correlation between horizontal and vertical movements are considered as indicator parameters defining the character of ground deformation. Spatial analysis of these coefficients values has identified high risk areas, and gives additional information in the geological structures definition

    SBAS-DlnSAR monitoring of subsidence induced by extracting brine from an underground salt deposit in Tuzla, Bosnia and Herzegovina

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    Tuzla City, Bosnia and Herzegovina, is very famous for salt mining. The intensive extraction of brine from the underground salt deposit caused accumulative subsidence of up to -12 m from 1956 to 2003. It induced serious damage to residences, buildings, and infrastructures. Although the activity of brine extraction was officially stopped in 2007, reports of subsidence are still on-going for some areas of Tuzla City according to a previous study. In the present study, a satellite-based method, i.e., Differential Synthetic Aperture Radar (DInSAR), is applied for the subsidence monitoring of the induced underground brine extraction. Since October 2014, SAR data obtained by the Sentinel-1A and -1B satellites (European Space Agency: ESA) and Small Baseline Subset (SBAS) multi-temporal analyses have been employed to obtain the spatial distribution and the temporal transition of the land subsidence. The accuracy and effectiveness of the SBAS-DInSAR method are assessed and evaluated by using the real-time kinematic GNSS monitoring system. DInSAR detected that the subsidence is still on-going at a velocity of -36.4 mm/year in some areas, especially in an area northeast of the center of the city. This study presents the validity and effectiveness of SBAS-DInSAR as a useful subsidence monitoring tool

    High natural radiation exposure in radon spa areas: a detailed field investigation in Niska Banja (Balkan region)

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    The measurement campaigns have been done in the rural community of Niska. Banja, a spa town located in southern Serbia, to evaluate population exposure to natural radioactivity. After a screening survey in 200 houses, annual radon and thoron concentrations were measured in 34 houses, and in 2004 a detailed investigation was carried out at six houses with elevated indoor radon concentrations. The paper presents the results of these detailed measurements. The complementary techniques were applied to determine radon and thoron concentrations in indoor air, in soil gas, radon exhalation from soil, soil permeability, and indoor and outdoor gamma doses. Soil and water samples were collected and analysed in the laboratory. Indoor radon and thoron. concentrations were found to be more than 1 kBq m(-3) and 200 Bq m(-3) respectively. Extremely high concentrations of soil-gas radon ( GT 2000 kBq m(-3)) and radon exhalation rates (1.5 mBq m(-2) s(-1)) were observed. These results will be utilised to set up the methodology for a more systematic investigation. (c) 2006 Elsevier Ltd. All rights reserved

    Card for Mr Wadsworth to attend Federal Capital Ceremony

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    The paper deals with a specific aspect of a general survey, that is being carried out during last ten years in several regions of Serbia (former Yugoslavia, former Serbia and Montenegro) to assess population exposure to natural radioactivity based on geochemical and integrative pattern research approach. The originality regarding this work is related to the facts such as follows: the first identification and assessment of high areas of natural radiation in Serbia which provides insight into its regional characteristics, the interpretation of the results in terms of geological aspects, building types and human habits, the first introduction and field applicability of both (surface and volume trap) retro techniques in Serbia and assessment of doses and risks to the population in investigated high natural radiation rural communities
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