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Radioluminescent emission in Ar, N 2 , O 2 , and dry air at P = 1 atm was observed induced by 5 MeV α particles. The wavelength range with a single detector spanned 250–1100 nm, extending the range well into the UV and IR bands with a single detector. Measured spectral lines for alpha-induced luminescence were corrected for detector transmission and intensities compared to previous work. The exploration of multiple gases over a wide frequency range opens the door to security and remote sensing applications, where different environments are routinely encountered. This work provides spectra that can be used in guiding future filter development focusing on remote alpha detection.

International audience; To ensure the quality of their products, manufacturers of nuclear materials currently rely on wet chemistry methods coupled with ICP-MS and ICP-AES. These methods are slow and sometimes hard to implement, which leads the manufacturers to seek new possibilities of online, fast and direct preliminary quality control. Thus, the issue of quantifying metal impurities in both uranium and plutonium matrices by LIBS has been raised. But the lack of calibrated samples and the harsh security constraints hinder any possibility of complete analytical development on these materials. Therefore, we propose a method relying on calibration transfer from several non-nuclear metal matrices to uranium and plutonium matrices. Calibration transfer is widely studied and used in various spectrometry methods in order to overcome slope differences that appear in calibration lines between different measuring instruments, different elements or matrices. Here, the latter case will be studied for each analyte, by measuring experimental data such as ablated mass of the sample (m0), and electron temperature (Te) and density (Ne) of the plasma, normalizations of the LIBS signal of one line will be advanced to try to correct the slopes of the calibration curves and, ideally, end up with only one normalized calibration curve for all matrices. This uniformed calibration will then be used to quantify impurities in uranium and plutonium without having to make a full calibration on those matrices, provided m0, Te and Ne are known.Temperature and density are determined in various metal matrices such as steel, aluminum, copper, nickel and titanium alloys. Since we aim to compare measurements between different matrices, it appears critical to use the same measurement method in all of them in order to avoid biases as much as possible. To achieve this, it is necessary to use lines from minor elements that can be found in most samples. Thus, we choose iron as our main element of interest and use its lines to assess Te and Ne through Boltzmann-Plots and Stark Broadening measurements respectively. Considering those methods are rarely used with minor elements, we strive to validate their precision and robustness in several ways. For Te we checked the coherence between measurements of iron lines and another minor element (titanium) on the one hand, and between measurements of lines with high and low energy levels on the other hand. For Ne we compared measurements obtained with the Stark Broadening method to that given by the Saha and Boltzmann equations.We first show that the Boltzmann-Plots obtained from the large variety of neutral iron lines show a very good linearity, which is consistent with the hypothesis of Local Thermodynamic Equilibrium. Moreover, preliminary measurements of Ne validate the McWhirter criterion. Then, we have demonstrated the possibility of reliably measuring Te in various metallic samples using lines of minor elements (thousands of ppm). This enables us to use a single set of lines to measure this parameter in various matrices with a unified approach. Lastly, the comparison of measured Te in different matrices show weak but nevertheless meaningful variations from one matrix to another, with up to 10% variation between aluminum and copper alloys it enables us to investigate matrix effects in the ablation plasma, which will complement previous results on the ablated mass and forthcoming results on the electron density. In this latter case, the choice of favorable lines of minor elements common to all matrices is quite limited and the development of a unified methodology is more challenging than for the plasma temperature. Preliminary investigations will be presented.

To ensure the quality of their products, manufacturers of nuclear materials currently rely on wet chemistry methods coupled with ICP-MS and ICP-AES. These methods are slow and sometimes hard to implement, which leads the manufacturers to seek new possibilities of online, fast and direct preliminary quality control. Thus, the issue of quantifying metal impurities in both uranium and plutonium matrices by LIBS has been raised. But the lack of calibrated samples and the harsh security constraints hinder any possibility of complete analytical development on these materials. Therefore, we propose a method relying on calibration transfer from several non-nuclear metal matrices to uranium and plutonium matrices. Calibration transfer is widely studied and used in various spectrometry methods in order to overcome slope differences that appear in calibration lines between different measuring instruments, different elements or matrices. Here, the latter case will be studied for each analyte, by measuring experimental data such as ablated mass of the sample (m0), and electron temperature (Te) and density (Ne) of the plasma, normalizations of the LIBS signal of one line will be advanced to try to correct the slopes of the calibration curves and, ideally, end up with only one normalized calibration curve for all matrices. This uniformed calibration will then be used to quantify impurities in uranium and plutonium without having to make a full calibration on those matrices, provided m0, Te and Ne are known.Temperature and density are determined in various metal matrices such as steel, aluminum, copper, nickel and titanium alloys. Since we aim to compare measurements between different matrices, it appears critical to use the same measurement method in all of them in order to avoid biases as much as possible. To achieve this, it is necessary to use lines from minor elements that can be found in most samples. Thus, we choose iron as our main element of interest and use its lines to assess Te and Ne through Boltzmann-Plots and Stark Broadening measurements respectively. Considering those methods are rarely used with minor elements, we strive to validate their precision and robustness in several ways. For Te we checked the coherence between measurements of iron lines and another minor element (titanium) on the one hand, and between measurements of lines with high and low energy levels on the other hand. For Ne we compared measurements obtained with the Stark Broadening method to that given by the Saha and Boltzmann equations.We first show that the Boltzmann-Plots obtained from the large variety of neutral iron lines show a very good linearity, which is consistent with the hypothesis of Local Thermodynamic Equilibrium. Moreover, preliminary measurements of Ne validate the McWhirter criterion. Then, we have demonstrated the possibility of reliably measuring Te in various metallic samples using lines of minor elements (thousands of ppm). This enables us to use a single set of lines to measure this parameter in various matrices with a unified approach. Lastly, the comparison of measured Te in different matrices show weak but nevertheless meaningful variations from one matrix to another, with up to 10% variation between aluminum and copper alloys it enables us to investigate matrix effects in the ablation plasma, which will complement previous results on the ablated mass and forthcoming results on the electron density. In this latter case, the choice of favorable lines of minor elements common to all matrices is quite limited and the development of a unified methodology is more challenging than for the plasma temperature. Preliminary investigations will be presented.

National audience; La LIBS possede de nombreuses qualites qui en font une technique adaptee au controle de procedes de fabrication en ligne. En particulier dans le cas de materiaux nucleaires, un tel controle est souhaitable afin de minimiser les temps de manipulation d'echantillons ; la rapidite et la simplicite d'execution de la LIBS en font donc une technique de choix.Cependant, une analyse quantitative fiable requiert generalement des etalonnages, qu'il n'est pas toujours possible de realiser sur lesdits materiaux. Notre approche consiste alors a choisir des materiaux simulant les materiaux nucleaires, puis a mettre en place une demarche de transfert d'etalonnage afin de surmonter les effets de matrice qui surviennent immanquablement et menent a une droite d'etalonnage differente pour chacune de ces matrices. L'objectif pratique du transfert d'etalonnage est donc de pouvoir realiser des mesures quantitatives sur un materiau a partir d'un etalonnage realise sur un autre materiau.Les effets de matrice en LIBS se traduisent par des variations des caracteristiques du plasma d'ablation. Notre objectif est donc de mettre en place une methode fiable de caracterisation du plasma au cours du temps pour les differentes matrices metalliques qui nous interessent. En mesurant, par des methodes spectroscopiques, la temperature Te et la densite electroniques Ne du plasma, nous cherchons a mettre au point une normalisation du signal LIBS qui permettra d'annuler les ecarts de pentes des droites d'etalonnage. Dans ce contexte, afin d'eviter au maximum les biais de mesure, nous utilisons plusieurs methodes differentes pour evaluer Te et Ne : diagrammes de Boltzmann simples et multi-elementaires pour la premiere, mesures d'elargissement Stark et utilisation des equations de Saha et de Boltzmann pour la seconde. Nous presenterons et comparerons ces methodes entre elles afin d'en evaluer la fiabilite et la coherence. Nous discuterons egalement des hypotheses qu'elles necessitent quant a la structure spatiale et a l'evolution temporelle du plasma d'ablation. Par la suite, nous nous efforcerons d'utiliser ces mesures pour relier empiriquement les caracteristiques du plasma aux proprietes physico-chimiques des materiaux, dans le but de pouvoir predire ces caracteristiques pour d'autres materiaux sans avoir besoin de realiser des mesures de Te et Ne.

The versatility of laser-induced breakdown spectroscopy (LIBS) as an analytical method for high-temperature applications was demonstrated through measurement of the concentrations of the lanthanide elements europium (Eu) and praseodymium (Pr) in molten eutectic lithium chloride–potassium chloride (LiCl-KCl) salts at a temperature of 500 °C. Laser pulses (1064 nm, 7 ns, 120 mJ/pulse) were focused on the top surface of the molten salt samples in a laboratory furnace under an argon atmosphere, and the resulting LIBS signals were collected using a broadband Echelle-type spectrometer. Partial least squares (PLS) regression using leave-one-sample-out cross-validation was used to quantify the concentrations of Eu and Pr in the samples. The root mean square error of prediction (RMSEP) for Eu was 0.13% (absolute) over a concentration range of 0–3.01%, and for Pr was 0.13% (absolute) over a concentration range of 0–1.04%.

Ecological studies on native bees in urban tropical environments are rare, however, ever-increasing urban areas world-wide necessitate study on how many of these bees can and have adjusted to human constructs. Predictable ecological patterns that emerge from these studies can provide guidance on how future urban constructs can be designed to provide habitat for conserving and protecting native bees. These patterns can also be used for bee habitat restoration in natural and agricultural environments. An extensive survey of native bees and honey bees and their relationships to a community of 102 plant types in urban residential environments of Bagaces and Liberia in northwestern Costa Rica was conducted from 2003–2012. Bees were attracted and recorded at measurable frequencies to 82 plant genera in 41 families, the most common of which was Fabaceae. Forty-two plant types were native ornamentals; 39 were non-natives; and 21 were native weed species. Standardized bee visitation (frequency) counts, 17...