Determination 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

peer reviewedThis 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

Material analysis and testing using a proton therapy facility

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.ProtherWa

Counting time measurement and statistics in gamma spectrometry: the balance

Nuclear counting statistics at high count rate are assessed on a γ-ray spectrometer set-up. Our typical gamma spectrometry system consists of a High Purity Germanium (HPGe) detector, liquid nitrogen cooling system, preamplifier, detector bias supply, linear amplifier, analog-to-digital converter (ADC), multichannel storage of the spectrum, and data readout devices. Although the system is powerful enough for background measurements, it is important, nowadays, to have a great statistical in short time measurement: which is a challenge for scientists. The purpose of this study was to determine the average time for gamma spectrometry measurement. To detect Uranium, Thorium and their respective daughters and Potassium series with a relative related error less than 1%, it was found that it is necessary to count during a minimum of 24 Hours (86,400 s). This result is in accordance to the literature with planar geometry detector. These results conduct us to make the following three guidelines for selecting the detector best suited for an application: 1. The more detector material available (germanium semi-conductor), the higher the full-energy peak efficiency. 2. The smaller the distance between the detector and the source material, the higher the full- energy peak efficiency. 3. While better resolution gives a better MDA, the resolution contributes only as the square root to the MDA value, whereas the MDA is proportional to the full-energy peak efficiency. This idea came to us by comparing the spectra of measuring radioactivity lasts for 12 hours in the day that does not fully covered the night spectra for the same sample. The conclusion after several investigations became clearer: to remove all effects of radiation from outside (earth, 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 measures 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 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

PIXE Analysis for the pigment identification in the Nizet manucript (18th century)

Written in 1740, the Nizet Manuscript is a heraldry book compiling the genealogy of the Nizet family (Verviers, Belgium). It presents a large number of hand-painted heraldries in traditional heraldic colours; the gold- and silver-like colours have undergone alteration and induced the degradation of the paper. The first inspection of the book with a binocular lens and UV-visible spectroscopy has led to the selection of representative points to be studied by PIXE analysis for the different groups of pigments. The PIXE measurements have been conducted with the cyclotron of the Institute of Nuclear and Atomic Physics and of Spectrometry of the University of Liege. Some pigments have been clearly identified, such as vermillion, umber or brass, while the presence of some others needs to be confirmed, for example azurite or lapis-lazuli. In the case of the green pigments and the organic ones (red, pink and black colours), the PIXE results must be completed by a molecular analysis. In order to exactly identify all the pigments, Raman analyses will be done to complete the pigment identification of the Nizet Manuscript

Early medieval glass in Burgundy. The Workshop of Mesvres and Autun

editorial reviewe

Set-ups for Radiation test campaigns of Materials dedicated to Space Applications

peer reviewedPROTHERWA