A comparison between Geant4 PIXE simulations and experimental data for standard reference samples

The Geant4 PIXE de-excitation processes are used to simulate proton beam interactions with sample materials of known composition. Simulations involve four mono-elemental materials; Cu, Fe, Si and Al and three relatively complex materials: stainless steel, phosphor bronze and basal BE-N reference material composed of 25 different elements. The simulation results are compared to experimental spectra acquired for real samples analyzed using 3 MeV incident protons delivered by an ion tandem accelerator. Data acquisition was performed using a Si(Li) detector and an aluminum funny filter was added for the three last mentioned samples depending on the configuration to reduce the noise and obtain clear resulting spectrum. The results show a good agreement between simulations and measurements for the different samples

On the optimization of the PIXE technique for thickness uniformity control of ultra-thin chromium layers deposited onto large surface quartz substrate

CAS-BIASChromium is a good candidate for obtaining conductive ultra-thin layers on insulator substrates such as quartz. The resistivity of such layers is highly related to the quality of the deposited chromium film. In order to optimize the deposition process, there is a need for rapid and accurate monitoring of such films (film thickness, thickness uniformity over a big surface, etc.). In this paper, we demonstrate the ability of the LE-PIXE technique, using proton energies <1 MeV, for the monitoring of the thickness and the thickness uniformity of ultra-thin (0.5 nm < t < 20 nm) chromium layers deposited onto quartz substrates. The acquisition time needed to obtain results with less than 3–4% precision was not, vert, similar5 min for the thinnest layers. The validation for the use of the LE-PIXE technique was checked by means of conventional RBS technique

Une production d'amphores "carottes" à Beyrouth à l'époque romaine ?

National audienceLes fouilles du centre-ville de Beyrouth ont mis au jour, entre autres vestiges, un atelier d'amphores daté du 1er siècle ap. J.-C. L'étude du dépotoir de cet atelier a permis d'identifier deux types d'amphores ainsi que des céramiques communes produits sur place. Les analyses chimiques d'un échantillonnage de ce matériel constituent des données de référence pour les productions romaines de Beyrouth. Ces données ont été utilisées pour tester l'attribution à Beyrouth de plusieurs autres types d'amphores, dont des types présumés orientaux diffusés jusqu'en Méditerranée occidentale, amphores «carottes» et autres conteneurs de petit module. Les résultats obtenus permettent de reconsidérer le rôle de Beyrouth dans le grand commerce méditerranéen à l'époque romaine. Ces recherches s'inscrivent dans le cadre d'un programme de collaboration franco-libanais «C.E.D.R.E». Les analyses chimiques ont été effectuées par PIXE au Laboratoire d'Accélérateur Ionique de Beyrouth, qui réalisait ses premières analyses de matériaux archéologiques. Le programme a donné lieu à la mise au point de protocoles expérimentaux et pose les premiers jalons d'une base de données d'analyse au laboratoire de Beyrouth centrée sur les céramiques levantines

Total boron assessment in soil samples from dry Mediterranean region using the thick target-particle induced gamma-ray emission technique

CAS-BIASAmong other trace elements, boron assessment in soils is important for assessing land quality in accordance with international criteria for landuse planning. In this paper the total boron concentrations, for more than 100 soil samples from one of the most important agricultural region in Lebanon (i.e. Akkar plain in the North), have been measured by the TT-PIGE technique using a proton beam. The specific boron gamma ray at 429 keV produced via the 10B(p, αγ)7Be nuclear reaction was used. Results are presented and discussed in relation to the lithological classes of the studied area. Furthermore, the method validation, for boron quantification in thick target soil samples using the TT-PIGE technique, employing external standards and using the so-called E1/2 analytical approach, is highlighted and discussed