The Moroccan TRIGA Mark II research reactor is to be equipped with a PGAA (Prompt Gamma Activation Analysis) facility to assist the country's progression in socioeconomic areas such as the environment and geochemistry, agriculture, health, industry, cultural heritage, and human sciences. The requirements of the PGAA facility include a very high thermal to fast neutron flux ratio and a focused, thin beam. Supermirror neutron guides are generally used to meet such requirements due to their ability to reflect neutrons with a specific energy and scattering angle. This study was undertaken to determine a suitable neutron guide for achieving optimal performance for the PGAA facility, where such a determination needs to be made according to both the available space and the minimum performance needed for PGAA analysis. To better parameterize the neutron guide, a set of simulations were performed with the aim of establishing the best guide specifications. Three types of neutron guides were studied, namely straight, curved, and bender. McStas code was used in this study, and the simulations showed that the guides must be 6 m long and that the coating value m must be equal to 5 for the bender and straight guides and 6 for the curved guide. Among the three guide types, the thermal/epithermal (Фth/Фep) and thermal/fast (Фth/Фfast) ratios were found to be much better when using the curved guide.

The aim of this work is to help inform the decision for choosing a convenient material for the PGAA (Prompt Gamma Activation Analysis) collimator plug to be installed at the tangential channel of the Moroccan Triga Mark II Research Reactor. Two families of materials are usually used for collimator construction: a mixture of high-density polyethylene (HDPE) with boron, which is commonly used to moderate and absorb neutrons, and heavy materials, either for gamma absorption or for fast neutron absorption. An investigation of two different collimator designs was performed using N-Particle Monte Carlo MCNP6.2 code with the ENDF/B-VII.1 and MCLIP84 libraries. For each design, carbon steel and lead materials were used separately as collimator heavy materials. The performed study focused on both the impact on neutron beam quality and the neutron–gamma background at the exit of the collimator beam tube. An analysis and assessment of the principal findings is presented in this paper, as well as recommendations.

The first installation around the tangential beam tube of the Moroccan TRIGA Mark II research reactor comprises combined instruments for Prompt Gamma Neutron Activation Analysis (PGAA) and Neutron Imaging (NI). The implementation of this project is divided over three main stages, namely the installation of the collimator and the primary beam shutter, which is a common section for introduction inside the reactor; the PGAA instruments’ installation; and finally, the installation of the PGNAA/NI combined instruments. The entire design was planned for this project, and detailed information about the first and the second stage is described in this work.

The Prompt Gamma Neutron Activation Analysis (PGAA) facility will be commissioned at the NB1 beam tube of the Moroccan TRIGA MARK II research reactor. PGAA is a non-destructive analytical technique used for multi-elemental analysis and especially for light element analysis. For better performances, PGAA requires small and focused beam, and high Фth/Фep and Фth/Фfast ratios, and low background gamma radiation. For this purpose, fast neutron filters are commonly used to reduce fast and epithermal components of neutron flux. In this paper, the impact of sapphire filter, introduced, within the collimator hole, at the beam port on neutron spectra was evaluated. Monte Carlo, MCNP6.2, code has been used with ENDF VII.1 neutron cross section library to perform this study. An approximate TRIGA MARK II reactor MCNP model has been used to generate neutron spectra at the entrance of the collimator. Then an independent model for both collimator and sapphire filter has been brought into calculation to fulfil our purpose. Results showed an increase of about 8 times for both Фth/Фep and Фth/Фfast ratios using a 10 cm length of sapphire.

The Triga Mark II research (TMRII) reactor is equipped with four horizontal channels and one thermal column. Tangential (NB1) and Percy (NB2) channels, subject of this work, are dedicated to PGAA&NI (Prompt Gamma Activation Analysis and Neutron Imaging) and ND (Neutron Diffraction) facilities respectively. A preliminary neutron characterization is primordial for each channel. Basic beam parameters including neutron flux and spectra were measured with activation detectors for the two channels (NB1, NB2). Activity measurement by spectrometry gamma was made with HPGe detector. SAND II code was used for evaluation of neutron spectra from multiple activation detector analysis and compared with the spectra obtained with Monte Carlo simulations. Comparison between experimental and simulated results shows good agreements regarding thermal and fast fluxes; otherwise, a small difference between the two methods has been detected in the epithermal component.

The k0-method of neutron activation analysis (k0-NAA) was used in order to determine the concentration of major and trace elements in sediment samples collected from different sites in the Gharb plain along the Sebou River (Morocco). Samples have been analyzed using neutrons of the Moroccan Triga Mark II research reactor. Two types of irradiation (short and long) have been carried out using the Pneumatic Tube System (PTS) and the Rotary Specimen Rack (RSR). Acquisition and Fitting of spectra have been carried out by Maestro software and k0-IAEA program respectively. Pollution indicators (enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (CF) and pollution load index (PLI)) were calculated to assess the pollution status of the sediments. Results of pollution indices showed no contamination all around the catchment area except for the stations (MS1 and MS2) located downstream the Sebou river. Principal component analysis (PCA) was carried out with the Pearson coefficient in order to determine possible relationships between major and trace elements. The comparison with other subsequent studies on Sebou river gives an idea about the temporal evolution of heavy metal contamination at national scale.

The aim of this work was to implement and to validate the k 0 standardization method in neutron activation analysis ( k 0 -NAA) at the Moroccan TRIGA Mark II research reactor. This technique was used in order to determine, the calibration of several HPGe detectors and calibration of neutron flux parameters in the typical irradiation channels [rotary specimen rack (RSR) and the pneumatic tube system (PTS) facilities]. Calibrations and calculations of k 0 -NAA results were carried out using the k 0 -IAEA program. The two parameters of neutron flux in the selected irradiation channels used for elemental concentration calculation, f (thermal-to-epithermal ratio) and α (deviation from the 1/ E distribution), have been determined as well in the PTS as in the RSR facilities using the zirconium bare triple method. Results obtained for f and α in two irradiation channels show that f parameter determined in this way is different in the RSR and the PTS facilities. This can be explained by the fact that the RSR channel is situated in a graphite reflector and is relatively far from the reactor core, while the PTS is in the core. Five reference materials of different origin obtained from USGS (basalt BE-N, bauxite BX-N, biotite mica-Fe, granite GS-N) and IAEA (Soil-7) were used to evaluate the validity of this method in our laboratory by analyzing the elemental concentrations with respect to the certified values. In general, good agreement was obtained between results of this work and values in certificates of the individual reference materials, thus proving the accuracy of our results and successful implementation of the method for analysis of real samples.

The Bouregreg river is one of the main rivers of Morocco, Its source being located in the Moroccan Central Massif and flows towards the Atlantic coast through the coastal Meseta. The Bouregreg river basin is located in the Moroccan Central Massif which consists mainly of Palaeozoic formations that were subject to the Hercynian orogeny. To evaluate the environmental status of the Bouregreg river water, sampling of the dissolved (<0.22 μm) and suspended (>0.22 μm) phases was performed at 10 sites along the Bouregreg river and its tributaries in the winter of 2005. Major (Na, Ca, K, Ti, Mn, Al and Fe), trace (As, Ba, Bi, Cd, Co, Cr, Cs, Cu, Hf, Li, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Sn, Sr, Ta, Th, U, V, W, Y, Zn and Zr) elements and rare earth elements were analysed. The dissolved and particulate phase of the Bouregreg river draining these contrasting zones show similar characteristics to those observed in other major tropical rivers such as the Congo and Amazon, and vary in composition between the different source areas. Obtained data show that the spectra of the standardized concentrations for all the determined elements in the dissolved and the suspended phase have the same form whatever the station and that the whole of the elements is strongly deficient compared to the upper continental crust. The strong depletion in the suspended phase and the associated enrichment in the dissolved phase suggest that some elements such as Rb, Ba and Sr are the most mobile elements during the weathering processes. The removal of the most mobile elements from the bedrock concentrates all remaining elements in the weathered phases of the soils, from whence it can be removed mechanically. As and Sb are strongly enriched as well in the dissolved load as in the suspended load.

The Bouregreg river basin is located in the Moroccan Central Massif which consists mainly of Palaeozoic formations that were subject to the Hercynian orogeny. This study documents the background geochemistry and hydrochemistry of the Bouregreg river basin, focusing on the distribution of major and trace elements. Rock samples were collected at nine locations along the Bouregreg River and its tributaries in the winter of 2005. Major (Al, Fe, Mn, Na, K and Ti) and trace (Rb, Cs, Sr, Sc, Ba, Cr, V, Co, Ni, Zn, As, Sb, La, Ce, Nd, Sm, Tb, Dy, Yb, Lu, Hf, Ta, Mo, Th and U) elements were analysed using instrumental neutron activation analysis. Data show that most of the geochemistry and hydrochemistry are related to regional and local geology. The geochemical heritage of geological environment in the Bouregreg river basin is very important, that results from the more compatible behaviour and the inertia of some elements during the weathering (3d transition elements (Co, Ni, Cr,…), interne transition elements f (lanthanides, Zr, Hf, Nb, Ta,…)). The geochemical homogeneity of the basin shows also heritage during the crustal accretion (magmatism-metamorphism-sedimentation) and the typology of this continental area is the same that the upper continental crust. Some anomalously high heavy metal analyses, particularly for As and Sb, may be related to anthropogenic activities.

The basin of Moulouya Oued is a region where mining industry has been developed early in the 20th century. As a consequence, residues generated from past mining activities over the years have been dumped as piles of tailings. Zaïda is one of the most affected region in this basin because of lead mine exploitation for long time. The aim of this study is to determine the amount of trace elements and the contamination of the river sediments. Analysis of collected samples has been achieved using the prompt gamma activation analysis method. The samples, in form of powders, were enclosed in Teflon sheets. The spectra were analyzed using HYPERMET PC software and the chemical composition is calculated using an Excel-macro that provides the concentrations as molar and weight percentages, as well as the corresponding masses of the oxides. The validation of the analytical method is demonstrated with the analysis of a reference material. The results show that the distribution of the studied metals (Pb, Zn, Cu, Cd, Cr Ni, and As) in the basin is dependent on location with a very significant contamination by Pb, Zn, Cu, Cd, Cr, and Ni close to the lead mine sites.

The aim of this study is to evaluate the sensitivity of Ko-method of Instrumental Neutron Activation Analysis for minor, trace and toxic elements in the most consumed foodstuff purchased from large commercial markets in Kenitra’s city (Morocco) which has been chosen for a pilot project on food monitoring in the west of Morocco. Samples have been analyzed by Ko-INAA method using TRIGA Mark II reactor at Josef Stefan Institute in Slovenia. The quality control of results was assessed using the Standard Reference Material SRM 1547 (Peach leaves). Results show an adequate sensitivity for the most studied elements in foodstuffs except for beef, onion and whole wheat which show a high sensitivity factor for Cd and As. INAA seems to be an adequate choice for element analysis in foodstuffs.

Elemental analyses of 10 geological samples from Morocco and some Standard Reference Materials were performed by Energy Dispersion X-Rays Fluorescence, Wavelength Dispersion X-Rays Fluorescence and Neutron Activation Analysis techniques in order to assess the accuracy and sensitivity of the concentrations determined with regard to requirements in geochemical exploration. The possibilities of utilization of EDXRF as an appropriate and economic technique for the analysis of various elements which are important in interpretation of geochemical data were evaluated.

Instrumental neutron activation analysis (INAA) for traces and major elements of several geological samples from “Zgounder” region in Morocco was performed utilizing the k 0-standardization method. Sample irradiation has been done by the 250 kW Triga Mark II reactor at Jozef Stefan Institute in Slovenia. Due to its accuracy, sensitivity and specificity, the k 0-standardization method is the most suitable method for non-destructive multielement analysis mainly for trace elements in rocks. It requires an accurate knowledge of the parameters of the irradiation facilities and other instrumentation parameters. It is an absolute standardization method, where the absolute nuclear data are replaced by a nuclear constant, the k 0-factor, determined experimentally with high accuracy. More than 40 elements were determined using about 30-second short and about 7-hour long irradiations. Gamma-rays emitted from the irradiated samples have been determined by a high purity germanium detector. Accuracy was assessed using the standard reference material AGV-1. This was less than 1% for major elements and about 5% for traces.

In this study, the accumulation sensitivities of trace elements in six types of air pollution biomonitors (lichens, tree barks and a moss) are compared. Three analytical methods were used: 14 MeV neutron activation analysis, thermal neutron activation analysis method and X-ray fluorescence analysis. Studies of the local concentration variations versus the sizes of lichen and of their altitude of collection from grounds, revealed that a standardisation of the procedures for collecting samples was necessary.

Four sites were selected in Sale's city in Morocco in order to contribute in air pollution level assessment and determination of its effects on public health. The sites were selected so that they are close to the most important industrialized areas, they have a very high demographic density and they cover a heavy traffic. Two approaches of air sampling and subsequent analysis methods of elements in atmospheric aerosols have been performed. The first is a classical approach, which consists in sampling total airborne materials with a High Volume Sampler and analysing the samples using Atomic Absorption Spectroscopy (AAS). The second is having its interest for studies relating effects of particles on human health. It consists in employing a Dichotomous Sampler to collect inhalable particles and the X-ray Fluorescence (XRF) for elemental analysis. With such system, it was possible to collect separately respirable and inhalable aerosols. The ED-XRF analysis method used is appropriate for monitoring airborne polluants in living and working areas with advantage of simple preparation, non-destructive nature, rapidity and suitable limits of detection. Using this method, it was possible to identify and quantify S, Ca, Cl, Fe, Cu, and Ph. With Atomic Absorption Spectroscopy Analysis Method, we quantified Cd. This study have been completed by measuring NOx, SO2 and solid suspended particles or airborne particulate matter (APM).

Two Moroccan cities were selected for assessing air pollution by the phosphate industry. El Youssoufia is a city close to one of the most largest phosphate mines in Morocco. The exploitation of this mine is probably the most important pollution source of the city. Safi is a city with important phosphoric acid and fertilizer industries. Samples were collected at the ground level. The approach to air sampling and subsequent elemental analyses of atmospheric aerosols has its interest for studies relating effects of particles on human health and source identification. It consisted in employing a dchotomous sampler to collect inhalable particles, followed by energy (EDXRF) for elemental analysis. With such systems, it was possible to collect separately respirable aerosols (aerodynamic diameter ≤ 2.5 µm) and inhalable aerosols (diameter 2.5 to 10 µm) on 2 different cellulose acetate membrane filters of pore size 0.45 µ m. EDXRF analyses have been performed using a Si(Li) detector, a planar Ge(HP) detector and radioactive sources (55Fe , 109Cd and 241Am). This nuclear analytical technique is appropriate for monitoring airborne polluants in living and working (OGR90) areas with the advantages of simple target preparation, rapidity and suitable limits of detection. The elemental determinations were assessed for accuracy by analyzing NIST standard reference material 3087a as filter. Measurement of solid suspended particles and airborne particulate matter complemented the study.