References of "Chene, Grégoire"
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See detailLate Roman Ware at Artena, Latium (3rd-7th c.): Archaeological Evidence and Archaeometric Data
Dienst, Simon ULiege; El Ouahabi, Meriam ULiege; Chene, Grégoire ULiege et al

Conference (2019, October 15)

This contribution aims to present the particularities of the assemblages from the Piano della Civita at Artena, near Rome, during Late Antiquity. Excavated since 1978 by a Belgian then Franco-American ... [more ▼]

This contribution aims to present the particularities of the assemblages from the Piano della Civita at Artena, near Rome, during Late Antiquity. Excavated since 1978 by a Belgian then Franco-American team under the supervision of Roger Lambrechts, then Cécile Brouillard and Jan Gadeyne, the artificial terrace of this Middle Republican settlement was later occupied by a complex succession of buildings. The Late Antique occupation, consisting mainly of farming and storage edifices, was followed by an early medieval structure with four golden solidi dated to 654-659 CE in the foundation. The study of the pottery from the Late Antique layers gives us valuable information about the economy and culture of this region. Very few assemblages from this time period around Artena have been published and the material culture seems clearly different from Rome. Our paper will present the characteristics of the pottery from Artena, using both typology, quantifications and archaeometry (XRF, PIXE/PIGE, CPAA). These data will then be compared to other assemblages from this period around Artena and at Rome. Lastly, they will be discussed in the light of regional connectivity, changes in the food practices and esthetical choices. Special attention will be paid to the question of the changes in the choice and the preparation of the clays for certain uses (cooking, tableware), as well as to the provenance of a great amount of cooking ware that in their forms and fabric is very different from the Roman ware as well as from the local ware of the valle del Sacco. [less ▲]

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See detail12 MeV Proton Activation Analysis combined to IBA techniques for compositional studies of various archeological artefacts from Roman and Merovingian sites (Ostia Antica, Artena, Nevers)
Chene, Grégoire ULiege; Defeyt, Catherine ULiege; Dienst, Simon ULiege et al

Poster (2019, September 18)

A combination of 3MeV proton PIXE-PIGE, MA-XRF and 10-15 MeV proton activation analysis has been recently applied on the external beam line of the cyclotron of IPNAS/CEA laboratory from the University of ... [more ▼]

A combination of 3MeV proton PIXE-PIGE, MA-XRF and 10-15 MeV proton activation analysis has been recently applied on the external beam line of the cyclotron of IPNAS/CEA laboratory from the University of Liège, and thus, to a wide variety of archaeological specimens (glass, pottery, mortars and pigments) all provided by on-going studies and excavations of housing materials, wall decorations, and vessels led on two remarkable Roman sites and one Medieval site: First, from an important agricultural complex excavated on an artificial terrace from a republican town, Artena, located, 40 km South-East from Rome, near the Via Latina and the Campania; second, from the Domus dei bucrani, a house dating from the end of the Republican era discovered on the site of the Schola of the Trajan at Ostia Antica and third, from the sixth-century glass mosaic from Saint Etienne church in Nevers, France. The aim of the present work is to explore and report the specific analytical interests of Charge Particle Activation Analysis implemented with protons ranging from 10 to 15 MeV, as a non-invasive analytical technique for the detection of elements with Z = 11–40 and beyond, and to address its suitability to solve questions raised by archaeologists. We present in this paper the preliminary results obtained following methodologies reported in recent pioneering and more recent works and emphasize on the achieved sensitivities (Limits of Detections) for elements as Ca, Ti, V, Cr, Fe, Cu, Zn, As, Sr, Y, Zr and Sb ranging from percentage to parts per million (ppm) levels. [less ▲]

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See detailSimultaneously gamma spectrometry & energy dispersive X-ray fluorescence-based color differentiation analysis of Douala-Bassa area’s soil
Guembou Shouop, Cébastien Joel ULiege; Ndontchueng Moyo, Maurice; Chene, Grégoire ULiege et al

in Environmental Technology and Innovation (2019), 16

The present study aims to characterize soil from the Douala Bassa area in Cameroon using energy dispersive X-ray fluorescence (EDXRF) and gamma-ray spectrometry techniques. In this regard, activity ... [more ▼]

The present study aims to characterize soil from the Douala Bassa area in Cameroon using energy dispersive X-ray fluorescence (EDXRF) and gamma-ray spectrometry techniques. In this regard, activity concentrations of 226Ra, 232Th, and 40K were assessed using a High Purity Germanium detector. Radium equivalent activity was computed from the measured activities concentrations of radionuclides, and no significant radiological risk due to natural radiation background was observed for the inhabitants and visitors of the investigation zone. The EDXRF technique enabled to determine elemental concentrations of trace elements and major compounds in the analyzed soil samples. The concentrations of different compounds and trace elements found as well as their ranges were displayed in graphical color. The geological provenance of the investigated soil was assessed using the measured data. It was observed that the investigated soil samples are classified as Fe-soil and are illustrative dregs from the Continental margin due to the considerable high concentration of Fe (its concentration ranged from 14.78% to 22.26 %). In addition, the diagram for the tectonic discrimination of sediment provenance provided important remark as studied samples are residue from Passive Margins. It can be concluded that the results of these two analytical methods could be used as baseline data for subsequent investigations of the soil provenance in the Littoral region. [less ▲]

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See detailBackscattered electron emission after proton impact on gold nanoparticles with and without polymer shell coating
Hespeels, Felicien; Heuskin, Anne-Caherine; Tabarrant, Tijani et al

in Physics in Medicine and Biology (2019), 64(12), 125007

This work aims at measuring experimentally proton induced secondary electron energy spectra after interaction with Gold Nano Particles (GNPs) and polymer-coated GNPs. Backscattered electron energy spectra ... [more ▼]

This work aims at measuring experimentally proton induced secondary electron energy spectra after interaction with Gold Nano Particles (GNPs) and polymer-coated GNPs. Backscattered electron energy spectra were collected over a 0 to 1000 eV energy range using a Retarding Field Analyzer. This paper presents the spectra obtained for proton beam energies of 0.5 and 2 MeV and diameter 2.5 and 3.8 nm GNPs. The spectra were also measured for 3.8 nm GNPs after 5 and 10 MeV proton irradiations. GNPs were deposited on a 100 nm carbon film. Each experimental spectrum was compared with dedicated simulations based on existing numerical models used in the TRAX and Geant4 Monte Carlo codes. For 100 nm carbon target, good agreement between experimental, TRAX and Geant4 simulation results can be observed. For 3.8 nm GNPs, the TRAX simulations reproduce with good agreement the electron energy spectra produced after 0.5, 2, 5 and 10 MeV proton irradiations, while Geant4 spectra display a lower secondary electron yield at low energy (<600eV) for all the studied energies. This underestimation can mostly be explained by the 790 eV threshold applied in the condensed history model used by Geant4 which impacts the secondary electron energy distribution. Results obtained for carbon and gold targets highlight the impact of the secondary electron production threshold for proton ionization process considered in condensed history models. The experimental results demonstrate that the single interaction approach used in TRAX is adapted to reproduce secondary electron emission from GNPs. On the other hand, the standard electron generation threshold implement in G4BetheBlochModel and G4BraggModel condensed-history models used in Geant4 is not adapted to reproduce low energy electron emission in gold targets. Finally, the results highlight that the GNP coating leads to a decrease of the electron yield and mostly affects low energy electrons (<500eV) emitted from GNPs. [less ▲]

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See detailPIXE-PIGE and Proton Activation Analysis of Analysis of Roman archeological artefacts
Strivay, David ULiege; Chene, Grégoire ULiege; Dienst, Simon ULiege et al

Poster (2019, June 11)

A combination of 3MeV proton PIXE-PIGE, MA-XRF and 10-15 MeV proton activation analysis has been recently applied on the external beam line of the cyclotron of IPNAS/CEA laboratory from the University of ... [more ▼]

A combination of 3MeV proton PIXE-PIGE, MA-XRF and 10-15 MeV proton activation analysis has been recently applied on the external beam line of the cyclotron of IPNAS/CEA laboratory from the University of Liège, and thus, to a wide variety of archaeological specimens (glass, pottery (terra sigillata), mortars and pigments) all provided by on-going studies and excavations of housing materials, wall decorations, and vessels led on two remarkable Roman sites: First, from an important agricultural complex excavated on an artificial terrace from a republican town, Artena, located, 40 km South-East from Rome, near the Via Latina and the Campania and second, from the Domus dei bucrani, a house dating from the end of the Republican era discovered on the site of the Schola of the Trajan in Ostia. The aim of the present work is to explore and report the specific analytical interests of Charge Particle Activation Analysis implemented with protons ranging from 10 to 15 MeV, as a non-invasive analytical technique for the detection of elements with Z = 11-40 and beyond, and to address its suitability to solve questions raised by archaeologists. We present in this paper the preliminary results obtained following methodologies reported in recent pioneering and more recent works1-4 and emphasize on the achieved sensitivities (Limits of Detections) for elements as Ca, Ti, V, Cr, Fe, Cu, Zn, As, Sr, Y, Zr and Sb ranging from percentage to parts per million (ppm) levels. [less ▲]

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See detailMaterial analysis and testing using a proton therapy facility
Strivay, David ULiege; Chene, Grégoire ULiege

Conference (2019, June 10)

A new Proteus (IBA) proton therapy facility will be installed at the Charleroi hospital in Belgium. In addition to medical applications, material analysis and testing will be developed. We will present ... [more ▼]

A new Proteus (IBA) proton therapy facility will be installed at the Charleroi hospital in Belgium. In addition to medical applications, material analysis and testing will be developed. We will present here the facility and the future material projects with this machine. A special feature will be the ability to get proton beams from 5 to 230 MeV. Ion beams can be used to modify the properties of materials or to carry out ionizing radiation withstand tests, for example for the space industry sector. Studies for applications in the space domain will mainly include radiation withstand testing of electronic components and coatings for the space industry. These measurements will be performed at different energies between 30 and 200 MeV. These energies are required to model the SEE (Single Event Effects) which are one of the main degradation phenomena for space systems subjected to the solar wind. The characteristics in terms of beam size and especially energy modulation will allow to associate ion beam analysis techniques such as PIXE (Particle Induced X-Ray Emission) and PIGE (Particle Induced Range ray emission). in the high energy mode to follow changes in irradiated materials in real time. The use of high energy beam (> 5MeV) will allow the effects to be analyzed at greater depths than by conventional techniques. These studies can therefore also be extended to other areas of research, particularly for the analysis of cultural heritage objects. As with the study of spatial components, the PBS mode (Pencil Beam Scanning) will accurately measure and modulate the dose received by each element of irradiated systems. [less ▲]

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See detailAnalysis of archeological artefacts from Ostia and Arena Roman sites by PIXE-PIGE and Proton Activation Analysis
Strivay, David ULiege; Chene, Grégoire ULiege; Dienst, Simon ULiege et al

Conference (2019, March)

A combination of 3MeV proton PIXE-PIGE, MA-XRF and 10-15 MeV proton activation analysis has been recently applied on the external beam line of the cyclotron of IPNAS/CEA laboratory from the University of ... [more ▼]

A combination of 3MeV proton PIXE-PIGE, MA-XRF and 10-15 MeV proton activation analysis has been recently applied on the external beam line of the cyclotron of IPNAS/CEA laboratory from the University of Li`ege, and thus, to a wide variety of archaeological specimens (glass, pottery (terra sigillata), mortars and pigments) all provided by on-going studies and excavations of housing materials, wall decorations, and vessels led on two remarkable Roman sites: First, from an important agricultural complex excavated on an artificial terrace from a republican town, Artena, located, 40 km South-East from Rome, near the Via Latina and the Campania and second, from the Domus dei bucrani, a house dating from the end of the Republican era discovered on the site of the Schola of the Trajan in Ostia. The aim of the present work is to explore and report the specific analytical interests of Charge Particle Activation Analysis implemented with protons ranging from 10 to 15 MeV, as a non-invasive analytical technique for the detection of elements with Z = 11-40 and beyond, and to address its suitability to solve questions raised by archaeologists. We present in this paper the preliminary results obtained following methodologies reported in recent pioneering and more recent works [1-4] and emphasize on the achieved sensitivities (Limits of Detections) for elements as Ca, Ti, V, Cr, Fe, Cu, Zn, As, Sr, Y, Zr and Sb ranging from percentage to parts per million (ppm) levels. [less ▲]

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See detailExperimental measurements validate the use of the binary encounter approximation model to accurately compute proton induced dose and radiolysis enhancement from gold nanoparticles
Hespeels, Félicien; Lucas, Stephane; Tabarrant, Tijani et al

in Physics in Medicine and Biology (2019), 64(6),

In protontherapy, it has been suggested that nanoparticles of high-Z material like gold (GNP) could be used as radiosensitizers. The origin of this enhancement phenomenon for proton radiation is not yet ... [more ▼]

In protontherapy, it has been suggested that nanoparticles of high-Z material like gold (GNP) could be used as radiosensitizers. The origin of this enhancement phenomenon for proton radiation is not yet well understood and additional mechanistic insights are required. Previous works have highlighted the good capabilities of TRAX to reproduce secondary electron emission from gold material. Therefore, TRAX cross sections obtained with the binary encounter approximation (BEA) model for proton ionization were implemented within Geant4 for gold material. Based on the TRAX cross sections, improved Geant4 simulations have been developed to investigate the energy deposition and radical species production around a spherical gold nanoparticle (5 and 10 nm in diameter) placed in a water volume during proton irradiation. Simulations were performed for incident 2 MeV proton. The dose enhancement factor and the radiolysis enhancement factor were quantified. Results obtained with the BEA model were compared with results obtained with condensed-history models. Experimental irradiation of 200 nm gold films were performed to validate the secondary electron emission reproduction capabilities of physical models used in Monte Carlo (MC) simulations. TRAX simulations reproduced the experimental backscattered electron energy spectrum from gold film with better agreement than Geant4. Results on gold film obtained with the BEA model enabled to estimate the electron emission from GNPs. Results obtained in our study tend to support that the use of the BEA discrete model leads to a significant increase of the dose in the near vicinity of GNPs (<20 nm), while condensed history models used in Geant4 seem to overestimate the dose and the number of chemical species for increasing distances from the GNP. Based on discrete BEA model results, no enhancement effect due to secondary electron emitted from the GNP is expected if the GNP is not in close proximity to key cellular functional elements (DNA, mitochondria...). © 2019 Institute of Physics and Engineering in Medicine. [less ▲]

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See detailDetermination of the natural radioactivity, elemental composition and geological provenance of sands from Douala in the littoral region of Cameroon using X-ray and γ-ray spectrometry
Guembou, Joel Cebastien Shouop; Ndontchueng, Maurice Moyo; Nguelem, Jilbert Eric Mekongtso et al

in Applied Earth Science (2019), 0(0), 1-14

This study aimed to determine the concentration of natural radionuclides, the chemical composition, and the geological provenance of sand samples from seven large quarries within the Douala Basin and ... [more ▼]

This study aimed to determine the concentration of natural radionuclides, the chemical composition, and the geological provenance of sand samples from seven large quarries within the Douala Basin and surrounding locations within the Littoral Region of Cameroon along the Gulf of Guinea. The analyses were undertaken on a total of 24 samples, using both gamma- and X-ray spectrometry techniques. Gamma spectrometric results indicated that the samples from the study area contained amounts of natural radioactivity that are less than the globally agreed safe limits. X-ray fluorescence spectrometry yielded quantitative major, minor, and trace element concentrations that were used in tectonic discrimination diagrams, indicating that these sediments were deposited in a passive margin environment. These concentration and natural radionuclide radioactivity level data provide a reference database for this region of Cameroon as well as for the wider Gulf of Guinea. [less ▲]

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See detailElemental quantification and radioactive characterization of soil from Douala Bassa Area: littoral region of Cameroon using EDXRF and γ-spectrometry technics
Guembou Shouop, Cébastien Joel ULiege; Moyo, Maurice Ndontchueng; Mekongtso, Eric Jilbert Nguelem et al

in Environmental Research Communications (2019), 1(6), 065001

The objectives of the present work were to characterize the investigated soil using Energy Dispersive X-Ray Fluorescence (EDXRF) and to evaluate the radioactivity concentration of the primordial ... [more ▼]

The objectives of the present work were to characterize the investigated soil using Energy Dispersive X-Ray Fluorescence (EDXRF) and to evaluate the radioactivity concentration of the primordial radionuclides with gamma-ray spectrometry based High Purity Germanium (HPGe) detector. Soil characterization using EDXRF in the present study gives an overview of the geological origin or provenience of the investigated area. As a result, the analysed soil samples can be classified chemically as Fe-soil and are illustrative dregs from the Continental margin because of high concentration of Fe (where the concentration of Fe in different soil sample ranged from 14.78% to 22.26 %) in all the investigated samples. The plotting of Al2O3/SiO2 (%) as a function of Fe2O3 and MgO (%) for the eighteen investigated samples points from Douala and a diagram for the tectonic discrimination of sediment provenance evidenced that all soil samples are residue from Passive margins. The observed activity concentration profile of the primordial radionuclides and the calculated radium equivalent activity show that no significant radiological risk can be observed for inhabitance within the study areas. As regard to that, the obtained results of the two analytical techniques can be seen as a baseline data for future investigations about elemental composition and radioactivity background levels in the study area. [less ▲]

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See detailDe bois, de pierre, de terre…et de verre. Approche de l’approvisionnement des chantiers alto-médiévaux à travers le cas de la mosaïque du baptistère de Nevers.
Van Wersch, Line ULiege; Neri, Elisabetta; Chene, Grégoire ULiege et al

Conference (2018)

Les découvertes de verre architectural qui se sont multipliées ces dernières années lèvent peu à peu le voile sur le rôle joué par de ce matériau dans les édifices alto-médiévaux. Les églises possédaient ... [more ▼]

Les découvertes de verre architectural qui se sont multipliées ces dernières années lèvent peu à peu le voile sur le rôle joué par de ce matériau dans les édifices alto-médiévaux. Les églises possédaient de véritables vitraux et le verre pouvait être incrusté dans les murs et les sols où il jouait un rôle dans la réflexion de la lumière. Dès lors, le besoin croissant de verre architectural a pu contribuer aux innovations techniques dans l’artisanat verrier du nord-ouest de l’Europe ainsi qu’à la mise en place de réseaux d’approvisionnement spécifiques en fonction des chantiers de construction. Attribuées au décor VIe siècle, les tesselles mises au jour lors des fouilles de la cathédrale de Nevers, dans le baptistère, sont un témoignage du début de ce processus. Les cubes sont majoritairement réalisés en verre, opaque et coloré ou incolore et recouvert d’une feuille d’or. Comme certains d’entre eux étaient encore insérés dans du mortier portant des traces de polychromie, leur attribution a une mosaïque pariétale est assurée. L’étude de ces objets et leur analyse en PIXE-PIGE et en raman, nous a permis d’identifier les matières premières et les techniques utilisées pour leur mise en œuvre. La comparaison avec des édifices contemporains a mis en exergue des points communs et les particularismes propres au site de Nevers, nous permettant de proposer une hypothèse pour l’approvisionnement des matériaux nécessaires à la décoration du baptistère. Cette étude révèle ainsi l’importance d’un chantier de mosaïque pariétale et la complexité des relations qu’il demande. [less ▲]

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See detailInter-techniques comparison of PIXE and XRF for Lake sediments
El Ouahabi, Meriam ULiege; Chene, Grégoire ULiege; Strivay, David ULiege et al

in Journal of Analytical Atomic Spectrometry (2018), 33(883 - 892),

In this paper we describe a validation procedure for chemical analysis of major elements and some minor elements as Sr, Cr, Ni, Zn and Zr in heterogeneous geological sediments. The procedure applies two ... [more ▼]

In this paper we describe a validation procedure for chemical analysis of major elements and some minor elements as Sr, Cr, Ni, Zn and Zr in heterogeneous geological sediments. The procedure applies two distinct techniques (PIXE and XRF) to the analysis of sediments. In this work an inter-technique comparison of the heterogeneous lacustrine sediments from the Amik Lake in the vicinity of the Roman city of Antioch (SE, Turkey) was carried out. Dried raw samples and with the addition of linking powder were analyzed using PIXE performed on the “Arkeo” beam line of the University of Liège AVF-Cyclotron and XRF (University of Liège). The aim of this work was to compare PIXE and XRF analysis with the set-ups routinely in use in the two laboratories. The purpose was also to determine the best combination of techniques and sample preparation protocol to be applied for heterogeneous sediments and the main elements of interest for each specific technique. The results are in agreement among the two techniques, with discrepancies concerning almost lighter and minor elements. These differences are related mainly to the texture of the sediments and the intrinsic features of the XRF and PIXE techniques. Major and selected minor elements are sensitive to the grain-size and the porosity of the samples. However, the accuracy of both XRF and PIXE requires the reduction of the grain-size or addition of linking powder to the sediments to fill the voids in order to increase the intensities of both lighter and minor elements. The results demonstrate the critical importance of sample treatment prior to analysis as well as the necessity of several measurement points and replicates to ensure the accuracy of the PIXE results. [less ▲]

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See detailLight Induced Super-Hydrophilicity in Niobium and Tantalum Oxides Thin Films
Henry, Théo ULiege; Bonsague, Fabio; Dubreuil, Olivier ULiege et al

Poster (2017, July)

Since its discovery at the end of the nineties by Wang et al.,[1] the interest for light-induced superhydrophilicity is ever growing. The application fields for materials displaying such a property are ... [more ▼]

Since its discovery at the end of the nineties by Wang et al.,[1] the interest for light-induced superhydrophilicity is ever growing. The application fields for materials displaying such a property are wide and numerous:[2] self-cleaning surfaces, anti-fogging, anti-bacterial, water and air purification, microfluidics…Nowadays, a research emphasis is on relatively low energy bandgap semiconductors, targeting a higher efficiency under solar irradiation or more precisely in the near UV and low-end of the visible spectral range. Here, however, we report UV-induced superhydrophilicity in metal oxides thin films showing a relatively high transparency in the UV. Reactive ion beam sputtering (IBS) was used to deposit niobium, tantalum and titanium oxides thin films with thickness ranging from 10 nm to 120 nm on fused silica substrates at room temperature. Contact angle measurements were performed for progressively increasing UV doses and also as function of elapsed time after the termination of the exposure in order to investigate the UV-induced hydrophilicity and recovery behavior of tantalum and niobium oxide thin films in comparison to that of titanium oxide deposited in analogous conditions. [less ▲]

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See detailAssessment of natural radioactivity and associated radiation hazards in sand building material used in Douala Littoral Region of Cameroon, using gamma spectrometry
Guembou Shouop, Cébastien Joel ULiege; Ndontchueng Moyo, Maurice; Chene, Grégoire ULiege et al

in Environmental Earth Sciences (2017), 76(164),

Twenty-four sand samples were collected from different sand quarries from Douala Littoral Region (Wouri, Dibamba, Mungo and Docteur Anse rivers and Atlantic Sea) along the Guinea Golf. These samples were ... [more ▼]

Twenty-four sand samples were collected from different sand quarries from Douala Littoral Region (Wouri, Dibamba, Mungo and Docteur Anse rivers and Atlantic Sea) along the Guinea Golf. These samples were investigated using gamma-ray spectrometry system. Highest values of 226Ra, 232Th and 40K measured specific activities expressed in Bq Kg−1 units were, respectively, 146.7 (in Youpoue–Bamenda 2) 102.9 (in Village 1) and 928 (in Northern Akwa 6) while the lowest values were found to be, respectively, 11.8 (in Northern Akwa 6), 8.0 (in Bonaberi–Bonamikano 4) and 54.0 (Youpoue 3). The potential radiological hazards parameters were assessed by calculating successively radium equivalent activity (Raeq), outdoor absorbed gamma dose rate (Dout), annual effective dose rate, internal hazard (Hin) and external hazard (Hex) indices and alpha and gamma index from using those sand in the construction of dwellings and large buildings. Results obtained show that annual dose absorbed by inhabitants due to sand construction use in Douala is below 1.0 mSv year−1. Therefore, most of the types of sands studied and incorporated in constructions appear to be safe as building material. The outputs from this research will be useful to assess the radiation hazards of sand building material in humans and to initiate a sand database together with a radiological map of the area at stake. [less ▲]

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See detailOptimal measurement counting time and statistics in gamma spectrometry analysis: The time balance
Guembou Shouop, Cébastien Joel ULiege; Penabei, Samafou; Ndontchueng Moyo, Maurice et al

Scientific conference (2017, January 04)

The optimal measurement counting time for gamma-ray spectrometry analysis using HPGe detectors was determined in our laboratory by comparing twelve hours measurement counting time at day and twelve hours ... [more ▼]

The optimal measurement counting time for gamma-ray spectrometry analysis using HPGe detectors was determined in our laboratory by comparing twelve hours measurement counting time at day and twelve hours measurement counting time at night. The day spectrum does not fully cover the night spectrum for the same sample. It is observed that the perturbation come to the sun-light. After several investigations became clearer: to remove all effects of radiation from outside (earth, the sun, and universe) our system, it is necessary to measure the background for 24, 48 or 72 hours. In the same way, the samples have to be measured for 24, 48 or 72 hours to be safe to be purified the measurement (equality of day and night measurement). It is also possible to not use the background of the winter in summer. Depend on to the energy of radionuclide we seek, it is clear that the most important steps of a gamma spectrometry measurement are the preparation of the sample and the calibration of the detector. [less ▲]

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See detailPrecision measurement of radioactivity in Gamma-rays spectrometry using two HPGe detectors (BEGe-6530 and GC0818-7600SL models) comparison techniques: Application to the soil measurement.
Guembou Shouop, Cébastien Joel ULiege; Samafou Penabei; NDONTCHUENG MOYO, Maurice et al

in MethodsX (2017), 4(42-54), 2017

To obtain high quality of results in gamma spectrometry, it is necessary to select the best HPGe detector for particular measurements, to calibrate energy and efficiency of gamma detector as accurate as ... [more ▼]

To obtain high quality of results in gamma spectrometry, it is necessary to select the best HPGe detector for particular measurements, to calibrate energy and efficiency of gamma detector as accurate as possible. To achieve this aim, the convenient detector model and gamma source can be very useful. The purpose of this study was to evaluate the soil specific activity using two HPGe model (BEGe-6530 and GC0818-7600SL) by comparing the results of the two detectors and the technics used according to the detector type. The relative uncertainty activity concentration was calculated for 226Ra, 232Th and 40K. For broad energy germanium detector, BEGe-6530, the relative uncertainty concentration ranged from 2.85 to 3.09% with a mean of 2.99% for 226Ra, from 2.29 to 2.49% with a means of 2.36% for 232Th and from 3.47 to 22.37% with a mean of 12.52% for 40K. For GC0818-7600SL detector, it was ranged from 10.45 to 25.55% with a mean of 17.10% for 226Ra, from 2.54 to 3.56% with a means of 3.10% for 232Th and from 3.42 to 7.65% with a mean of 5.58% for 40K. The average report between GC0818-7600SL model and BEGe-6530 model was calculated and showed the mean value of 3.36. The main study was based on the following points: • Determination of The relative uncertainty activity concentration of 226Ra, 232Th and 40K • Determination of the relative uncertainty related to the radium equivalent activity to compare the performance of the two detection systems • Proved that the activity concentration determination in gamma spectrometry depended on the energy range emitted by a radionuclide. This study showed that the standard deviation measurement was less important to the result realized with BEGe-6530 HPGe model. Our findings were demonstrated that the results of the Broad Energy Germanium detector were more reliable. [less ▲]

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See detailThe scientific analyses of glass vessels
Van Wersch, Line ULiege; Biron, Isabelle; Mathis, François et al

in Theuws, F.; Kars, M. (Eds.) The Saint-Servatius complex in Maastricht. The Vrijthof excavations (1969-1970) (2017)

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