scholarly journals Radiological impact of phosphogypsum surface application in a no-till system in Southern Brazil

2010 ◽  
Vol 45 (12) ◽  
pp. 1456-1464 ◽  
Author(s):  
Nivea Maria Piccolomini Dias ◽  
Eduardo Fávero Caires ◽  
Luiz Fernando Pires ◽  
Márcio Arruda Bacchi ◽  
Elisabete Aparecida de Nadai Fernandes
Keyword(s):  
Field Experiment ◽  
Human Health ◽  
Gamma Ray ◽  
Gamma Ray Spectrometry ◽  
Southern Brazil ◽  
Small Reduction ◽  
No Till ◽  
Hpge Detectors ◽  
Radiological Impact ◽  
The Impact

The objective of this work was to determine the impact of phosphogypsum application on 226Ra and 228Ra activities in the soil and on their accumulation in soybean grains. A field experiment was carried out in Paraná state, Brazil, on a loamy Typic Hapludox, under no-till system, with increasing phosphogypsum rates: 4, 8, and 12 Mg ha-1. GammA ray spectrometry was carried out using HPGe detectors with 45 and 10% relative efficiencies, for soybean grains and soil, respectively. No increment of 226Ra and 228Ra activities was observed due to the increase in phosphogypsum rates in the soil, and a small reduction was noticed in the grains. Average values found for 226Ra and 228Ra activities were 37 and 57 Bq kg-1 in the soil and 1.44 and 3.19 Bq kg-1 in soybean grains. The application of phosphogypsum for no-till soybean production is a safe practice regarding the risks of radiation damage to human health

scholarly journals Pile-up correction for coincidence counting using a CAEN 1724 digitizer

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Guilherme Soares Zahn ◽  
Iberê Souza Ribeiro Jr ◽  
Frederico Antonio Genezini
Keyword(s):  
Gamma Ray ◽  
Pulse Generator ◽  
Dead Time ◽  
Gamma Ray Spectrometry ◽  
Coincidence Counting ◽  
60Co Source ◽  
Hpge Detectors ◽  
Pile Up ◽  
Peak Areas ◽  
The Dead

In conventional gamma-ray spectrometry, the probability of pile-up effects is considered to be proportional to the dead-time, and is usually neglected for low dead-times (below 4-5%). In gamma-gamma coincidence spectrometry, though, while the dead time takes into account only events that are actually digitized, the pile-up effects are proportional to the actual gamma-ray detection rate in each detector, not only to the ones that trigger the coincidence gate. Thus, the pile-up corrections may not be so easy to assess as in single spectrometry systems. In this work, a system composed of two HPGe detectors coupled to a CAEN v1724 digitizer is studied. A 3kBq 60Co source was analyzed, both alone and in the presence of other radioactive sources (137Cs, 133Ba and 152Eu), and the resulting coincidence peak areas were compared to assess the effectiveness of two distinct corrections: a simple normalization by the live time of acquisition and the normalization by the count rate obtained using a pulse generator. The results obtained stress the need to use the pulse generator in this specific setup in order to get accurate results.

scholarly journals GAMMA-RAY SPECTROMETRY AS A TOOL FOR MAPPING PETROGRAPHIC DOMAINS IN GRANITOIDS: THE EXAMPLES OF THE CUNHAPORANGA AND TRÊS CÓRREGOS GRANITIC COMPLEXES, PARANÁ STATE, SOUTHERN BRAZIL

2014 ◽  
Vol 32 (3) ◽  
pp. 465 ◽  
Author(s):  
Francisco J.F. Ferreira ◽  
Luiz Fornazzari Neto ◽  
Luizemara S.A. Szameitat ◽  
Gilson B. Guimarães ◽  
Victor M. Oliveira Martin ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Gamma Ray ◽  
Gamma Ray Spectrometry ◽  
Southern Brazil ◽  
Serra Do Mar ◽  
Original Distribution ◽  
Ray Patterns

ABSTRACT. The Aerogeophysical Project Serra do Mar Sul compiled gamma-ray data in the 70’s, for a large basement area (50,000 km2) in Paraná state, southernBrazil. The cps data were corrected in 1997 by BARMP, Brazil Airborne Radiometric Mapping Project, and are available now as TC (eU), K (%), eTh and eU (in ppm). Thedata for the two large intrusions in the region, the Cunhaporanga Granitic Complex (CGC) and Trˆes C´orregos Granitic Complex (TCGC) were used to generate maps forK, eTh, eU, total counts, and several derived parameters: eTh/K, eU/K, eU/eTh, F. Contrasts between the two complexes are explained as a result of outcrop pattern andweathering (CGC more weathered than TCGC) and differences in overall Th content (eastern TCGC domains richer in the element), but a more uniform U distribution.The differences are enhanced in the eTh/K map (TCGC with lower ratios). The late alaskitic Serra do Carambe´ı intrusion in the CGC shows the highest Th and U values.Gamma-ray patterns in granites subjected to strong subtropical alterations, with heavy seasonal rains, are more difficult to interpret, considering the possibility of strongleaching of K by weathering, and also supergene mobility of U, factors that are absent, or less important, in areas with drier climates. The gamma-ray patterns of thethree elements are influenced by their original distribution in the granites, but can be drastically changed by late hydrothermal alteration and weathering.Keywords: granitic complexes, gamma-ray spectrometric maps, BARMP. RESUMO. O Projeto Aerogeofísico Serra do Mar Sul, da década de 70, gerou mapas gamaespectrométricos para uma região de 50.000 km2 de embasamentocristalino no Estado do Paraná, Brasil meridional. Valores em cps foram corrigidos para TC (eU), K (%), eTh e eU (em ppm) no Brazil Airborne Radiometric MappingProject, BARMP, em 1997. Dados para as grandes intrusões da região, os complexos Graníticos Cunhaporanga (CGC) e Três Córregos (TCGC), foram utilizadospara gerar mapas de K, eTh, eU, contagem total e dos parâmetros eTh/K, eU/K, eU/eTh, F. Os contrastes entre os dois complexos são explicados pelo padrão de afloramentos e intemperismo (CGC mais intemperizado que TCGC) e diferenças no teor geral de Th (domínios leste do TCGC enriquecidos no elemento) mais que do U. Estas diferenças são salientadas no mapa eTh/K (TCGC com razões menores). O Granito Serra do Carambeí, uma intrusão alasquítica tardia no CGC, mostra os teoresmais elevados de Th e U. Padrões de raios gama em granitos submetidos a um acentuado intemperismo subtropical (com fortes chuvas sazonais) são de interpretação mais dif´ícil que os de regiões com climas mais secos, em razão da possibilidade de lixiviamento total de K por intemperismo, e mobilidade supêrgena do U. Essesmapas indicam o padrão geral de distribuição de K, Th e U, eventualmente com mudanças drásticas impostas por alteração hidrotermal e especialmente intemperismo.Palavras-chave: complexos graníticos, mapas gamaespectrométricos, BARMP.

scholarly journals Overland flow characterization under no-tillage in Southern Brazil

2020 ◽  
Author(s):  
Fabio José Andres Schneider ◽  
Jean Paolo Gomes Minella ◽  
Ana Lucia Londero ◽  
Dinis Deuschle ◽  
Alice Prestes Bisso Dambroz ◽  
...  
Keyword(s):  
Flow Control ◽  
Surface Runoff ◽  
Overland Flow ◽  
Zero Order ◽  
Economic Damage ◽  
Southern Brazil ◽  
Conservation Practice ◽  
No Till ◽  
The Impact ◽  
Runoff Plots

<p>No-till is considered an efficient soil and water conservation practice when accompanied by crop species diversification and overland flow control. However, the last twenty years in south Brazil, farmers under no-till abandoned crop diversification and others soil conservation practice. As a consequence, severe erosion process have been observed caused by overland flow. The overland flow has been intensified due to a combination of problems such as soil compaction and poor surface residues. Understanding the formation and propagation of overland flow when the no-till is submitted to different agronomic conditions and practices mechanics as terraces is crucial for the improvement of conservationist agriculture, since many associated problems have caused environmental and economic damage. Unfortunately, there is currently a lack of information about the surface runoff processes occurring under no-till, which is essential to define the best water management practices. The objective of this study was to determine parameters related to surface runoff under different conditions of no-till, specifically regarding the amount of biomass, mechanical scarification and presence of terraces. The study was performed at the hillslope scale in southern Brazil characterized by a deep, clay and weathered soil under no-till. Two zero order catchments (2.4ha) and four hillslopes runoff plots (0.5ha) were monitored during natural rainfall from 2014 to 2018. These catchments and runoff plots are paired and have different soil management to test their respective effects on infiltration and overland flow. In the catchments the presence of terraces was evaluated and in the runoff plot the amount of biomass and mechanical scarification was evaluated. Precipitation was measured with pluviographs and overland flow was carried out automatically on H flumes with sensor pressures. A set of 63 rainfall-runoff events were monitored at the outlet of zero order catchments (2,4ha) and 27 events were observed in the along the runoff plots (0.5ha). From these events, we derived information reflecting the influence of mechanical scarification, of terraces and of biomass. The variables derived for each management mode were: Runoff coefficient (RC), Peak water discharge (PWD), Curve Number (CN), Sediment Yield (SY) and apparent infiltration (AI). In catchments, the main results demonstrate a, influence of terraces on overland flow control, where the reduction reached 50% for RC, 12% for CN, and 60% for PWD, and 70% for SSC. Furthermore, infiltration increased by 11%. In runoff plots, the influence of increasing biomass with scarification the reduction was 16% for RC, 5% for CN, 6.3% for PWD and 6% for SSC. In runoff plots, the influence of increasing biomass without scarification the reduction was 27% for RC, 5.4% for CN, 13% for PWD and 81% for SSC. The results demonstrated that the presence of terraces mitigated the overland flow; however, despite the positive effect of amount of biomass and mechanical scarification, its performance is of less impact. This set of original results will provide the data to quantify the impact of different management conditions and will assist the local managers in the planning of conservationist practices adapted to the conditions observed in Southern Brazil.</p>

Gamma-ray spectrometry observations to monitor a presumed meteoritic signature at Maâdna crater (Talemzane, Algeria)

2020 ◽  
Author(s):  
Atmane Lamali ◽  
Lamine Hamai ◽  
Sid Ahmed Mokhtar ◽  
Abdelkrim Yelles-chaouche ◽  
Abdeslam Abtout ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Sedimentary Rocks ◽  
Clay Content ◽  
Gamma Ray Spectrometry ◽  
Gamma Spectrometer ◽  
Geophysical Method ◽  
Impact Cratering ◽  
High Level ◽  
The Impact

<p>By measuring changes in radioelement concentrations, gamma-ray spectrometry is increasingly emerging as an efficient geophysical method that allows such changes to be geologically mapped according to lithology and soil type. At Maâdna crater in southern Algeria, this method has been used to monitor any changes in the composition of the target rocks that may be associated with the impact cratering process. For this purpose, several measurements were carried out in situ using a portable field gamma spectrometer. As a result, most predominantly calcareous surface lithologies, exposed on the rim and flanks of the crater, showed a very low emitted radiometric response over the three channels (K, Th, U). However, no more than 90 Cps were counted both inside and outside the crater. Such a rate is indeed expected in sedimentary rocks with low clay content, and this remains valid, as long as other exogenous mineralogical enrichments are excluded. On the other hand, the contoured radioelement concentrations maps, have demonstrated an anomalous enhanced gamma radiation levels of potassium-dominated peaks over the central part of the crater and in the surrounding wadis. Nevertheless, the central potassium anomaly is well correlated with the shallower magnetic one that has been described in previous studies (see e.g. Lamali et al., 2016). Therefore, either near the surrounding wadis or in the central part of this crater, this anomalously high level of radioactivity may be linked to an accumulation of later altered deposits. Consequently, there are no objective criteria to link these results to an impact event occurring at the Maâdna structure, similar to what was done at the Serra da Cangalha crater (Vasconcelos et al., 2012).</p>

scholarly journals Measurement of anthropogenic radionuclides in post-Fukushima Pacific seawater samples

Nukleonika ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 545-550 ◽  
Author(s):  
Guillaume Lutter ◽  
Faidra Tzika ◽  
Mikael Hult ◽  
Michio Aoyama ◽  
Yasunori Hamajima ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Power Plant ◽  
North Pacific ◽  
Nuclear Power ◽  
Gamma Ray ◽  
Gamma Ray Spectrometry ◽  
Anthropogenic Radionuclides ◽  
Vast Number ◽  
Hpge Detectors ◽  
Seawater Samples

Abstract Following the accident at the Daiichi Fukushima nuclear power plant in 2011, a vast number of Pacific seawater samples from many locations far from Fukushima have been collected by Japanese investigators. Due to dilution, the activities of radionuclides from North Pacific seawater samples are very low, which calls for extraordinary measures when being measured. This study focuses on the metrological aspects of the gamma-ray spectrometry measurements performed on such samples in two underground laboratories; at HADES (by JRC-IRMM in Belgium), and at Ogoya (by Kanazawa University in Japan). Due to many samples and long measurement times, all available HPGe detectors needed to be employed. In addition to single coaxial detectors, this involved multidetector systems and well detectors. Optimization of detection limits for different radionuclides and detectors was performed using Monte Carlo simulations.

scholarly journals Quantifying the impact of no‐till on runoff in southern Brazil at hillslope and catchment scales

2021 ◽  
Vol 35 (3) ◽  
Author(s):  
Ana L. Londero ◽  
Jean P. G. Minella ◽  
Fabio J. A. Schneider ◽  
Dinis Deuschle ◽  
Danrlei Menezes ◽  
...  
Keyword(s):  
Southern Brazil ◽  
No Till ◽  
The Impact

scholarly journals Quantifying the impact of no‐till on sediment yield in southern Brazil at the hillslope and catchment scales

2021 ◽  
Author(s):  
A. L. Londero ◽  
J. P. G. Minella ◽  
F. J. A. Schneider ◽  
D. Deuschle ◽  
G. H. Merten ◽  
...  
Keyword(s):  
Sediment Yield ◽  
Southern Brazil ◽  
No Till ◽  
The Impact

scholarly journals The dependence of Ge detectors efficiency on the density of the samples in gamma-ray spectrometry

2007 ◽  
Vol 22 (2) ◽  
pp. 58-63 ◽  
Author(s):  
Ivana Vukasinovic ◽  
Dragana Todorovic ◽  
Dragana Popovic
Keyword(s):  
Energy Range ◽  
Gamma Spectrometry ◽  
Environmental Samples ◽  
Gamma Ray ◽  
Milk Powder ◽  
Counting Efficiency ◽  
Standard Reference Materials ◽  
Gamma Ray Spectrometry ◽  
Regression Parameters ◽  
Hpge Detectors

The effect of the density of environmental samples on the counting efficiency of Ge detectors used in gamma-spectrometry was studied. The dependence ?ff(?) was determined for two HPGe detectors (relative efficiencies 18% and 20%) using five radioactive standard reference materials (silicone resins, epoxy resin, milk powder, soil) with different matrix densities (0.45-1.22 g/cm3) in Marinelli beakers (V = 500 cm3). The dependence of efficiency vs. density was found to be linear and the regression parameters for energies in the range of 60-2000 keV were determined, too. The effect of variation in density on the counting efficiency of Ge detectors is dominant in the range of lower energies (60-600 keV) and de creases with energies in the higher energy range.

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