In this paper, we propose a new hybrid processing method for generation of multiplexed holograms for display purposes. This method-named the NOE method-is very simple, and combines the rapidity of ...optical restitution, the flexibility of numerical computation and the simplicity of electrical control, in order to allow a large number of objects to be stored. The computer generates a multiplexed grating profile, leaving the Fourier transform to the optical restitution step. Image plane holograms are generated, for white light reconstruction, by a set of independent white light sources.
The EDELWEISS collaboration performs a direct search for WIMP dark matter in a low-background environment in the Laboratoire Souterrain de Modane. Results obtained with a 320 g heat-and-ionization ...detector are presented. No nuclear events are observed in the fiducial volume in the 30–200 keV energy range in an effective exposure of 4.53 kg.day. The central value of the signal reported by the DAMA experiment NaI1-4 is thus excluded at 90% CL. The R&D program and the EDELWEISS-II stage of the experiment, are also briefly described.
The EDELWEISS collaboration is performing a direct search for WIMP dark matter in a low-background environment in the Laboratoire Souterrain de Modane. Two series of results obtained with 320 g ...heat-and-ionization detectors are presented. During the 4.53 effective exposure of the year 2000 run, no nuclear events are observed in the fiducial volume in the 30–200 keV energy range. The central value of the signal reported by the DAMA experiment NaI1–4 is thus excluded at 90% CL. The present 2002 setup with three detectors is described and improved calibration performances are presented. The R&D program and the EDELWEISS-II stage of the experiment are also briefly described.
Abstract A new method for the direct measurement of 237 Np/ 238 U ratio in irradiated UO 2 pellets by multicollection inductively coupled plasma mass spectrometry (MC-ICP-MS) is proposed. It allows ...the determination of ratios down to 10 × 10 –6 mol·mol −1 using ion counter and Faraday cup. This approach was validated by intercomparison with the usual two-step-method (Quadrupole ICP-MS for 237 Np determination and isotope dilution mass spectrometry (IDMS) for 238 U). For ratios between 10 × 10 –6 and 100 × 10 –6 mol·mol −1 , expanded uncertainties ( k = 2) varied from 2.75% to 0.81%, twice lower than the uncertainties determined by the usual method.
In the framework of trace element analysis by Q ICP-MS in a simulated deep Callovo-Oxfordian groundwater, separation procedures based on extraction chromatography were developed to eliminate the high ...salt contents and to concentrate Zr and U simultaneously. Theoretical and experimental speciation studies showed the importance of adjusting the medium to HNO3/HF (0.5M/0.005M) to guarantee the stability over time of the analytes before removal of the matrix. Two preconcentration methods based on TRU® and TODGA® resins were optimized for the simultaneous isolation of Zr and U prior to Q ICP-MS measurements. Using TRU resin, alkali and alkali earth metals contained in the deep groundwater were removed with 2M HNO3 whereas Zr and U were recovered with a HNO3/NH4HC2O4 (0.02M/0.05M) medium. For the separation protocol based on TODGA resin, alkali and alkali earth metals were eliminated with 3M and 11M HNO3 while Zr and U were simultaneously stripped with a HNO3/HF (0.5M/0.2M) medium. The procedure optimized on TODGA resin was validated with the French AFNOR NF T90-210 standard by studying linearity, limits of quantification (LOQ) and separation yields. The LOQ was determined at 0.008μgL−1 for Zr and U after the separation. Both analytes were recovered quantitatively. Compared to a sample dilution implemented to reduce the matrix effects, the developed preconcentration method allowed improving the sensitivity up to a 20 fold factor for Zr and U measurements at trace level by Q ICP-MS.
► The analysis of Zr and U is proposed in a simulated deep groundwater by Q ICP-MS. ► The stability of both analytes in solution was guaranteed from speciation studies. ► TRU and TODGA-based preconcentration procedures were developed. ► The methods were validated with the French AFNOR NF T90-210 standard.
In the general frameworks of the nuclear fuel cycle and environmental research field, the Cs isotopic composition must be known with high precision and accuracy. The direct determination of Cs ...isotopes by mass spectrometry techniques is generally hampered by the presence of Ba isobaric interferences however. Here we present a new method which takes advantage of the collision-reaction cell based Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) and allows to analyse Cs isotopes in the presence of Ba without prior separation step. The addition of N2O gas in the cell leads to an antagonistic behavior of Cs+ and Ba+ as the latter reacts with the gas to form BaO+ and BaOH+ products whereas Cs+ remains unreactive. The efficiency of the method was demonstrated for an UOx sample by comparing the results obtained (1) from the measurements of pure Cs fractions and (2) from Fission Products fractions containing more than 30 ionisable elements in addition to Cs, Ba, and where U and Pu were previously removed by using ion exchange resin. An excellent agreement is achieved between each set of experiments with an external reproducibility always better than 0.5% (RSD, k=2). This study confirms the strong potential of collision–reaction cell to measure Cs isotopes in presence of interfering Ba, precluding therefore former systematic chemical separations.
In the nuclear domain, precise and accurate isotopic composition determination of elements in spent nuclear fuels is mandatory to validate neutron calculation codes and for nuclear waste disposal. ...The present study presents the results obtained on Cs isotope ratio by mass spectrometric measurements. Natural cesium is monoisotopic (
133Cs) whereas cesium in spent fuels has 4 isotopes (
133Cs,
134Cs,
135Cs, and
137Cs). As no standard reference material is available to evaluate the accuracy of Cs isotopic measurements, a comparison of cesium isotopic composition in spent nuclear fuels has been performed between Thermal Ionization Mass Spectrometry (TIMS) and a new method involving Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) measurements. For TIMS measurements, isotopic fractionation has been evaluated by studying the behavior of cesium isotope ratios (
133Cs/
137Cs and
135Cs/
137Cs) during the analyses. For MC-ICPMS measurements, the mass bias effects have been corrected with an external mass bias correction using elements (Eu and Sb) close to cesium masses. The results obtained by the two techniques show good agreement: relative difference on
133Cs/
137Cs and
135Cs/
137Cs ratios for two nuclear samples, analyzed after chemical separation, ranges from 0.2% to 0.5% depending on the choice of reference value for mass bias correction by MC-ICPMS. Finally the quantification of the
135Cs/
238U ratio by the isotope dilution technique is presented in the case of a MOx (mixed oxide) spent fuel sample. Evaluation of the global uncertainties shows that this ratio could be defined at an uncertainty of 0.5% (
k
=
2). The intercomparison between two independent mass spectrometric techniques is fundamental for the evaluation of uncertainty when no isotopic standard is available.
A one step Cs, lanthanides (Ln), Pu and U separation using TRU resin (Eichrom), for subsequent isotopic analyses, is presented for samples of transmutation targets containing a predominant matrix of ...steel elements. Cs, Ln, Pu and U are successively eluted using minor volumes (<12 mL) of 2M HNO
3
, 4M HCl, 0.075M oxalic acid in 1M HCl media and 0.1M ammonium hydrogen oxalate in 0.02M HNO
3
media, respectively. Accurate and precise isotopic compositions obtained for these elements by thermal ionization mass spectrometry or multiple collector inductively coupled mass spectrometry show neither significant fractionation nor contamination during the complete analytical process.
In the general frameworks of the nuclear fuel cycle and environmental research field, the Cs isotopic composition must be known with high precision and accuracy. The direct determination of Cs ...isotopes by mass spectrometry techniques is generally hampered by the presence of Ba isobaric interferences however. Here we present a new method which takes advantage of the collision-reaction cell based Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) and allows to analyse Cs isotopes in the presence of Ba without prior separation step. The addition of N
2O gas in the cell leads to an antagonistic behavior of Cs
+ and Ba
+ as the latter reacts with the gas to form BaO
+ and BaOH
+ products whereas Cs
+ remains unreactive. The efficiency of the method was demonstrated for an UOx sample by comparing the results obtained (1) from the measurements of pure Cs fractions and (2) from Fission Products fractions containing more than 30 ionisable elements in addition to Cs, Ba, and where U and Pu were previously removed by using ion exchange resin. An excellent agreement is achieved between each set of experiments with an external reproducibility always better than 0.5% (RSD,
k
=
2). This study confirms the strong potential of collision–reaction cell to measure Cs isotopes in presence of interfering Ba, precluding therefore former systematic chemical separations.
Nous proposons une méthode de contrôle non destructif de durabilité des matériaux cimentaires. La méthode est fondée sur l'analyse de la microporosité par des micro-transducteurs ultrasoniques haute ...fréquence. Nous présentons des éléments de réalisation et de caractérisation de tels dispositifs. Leur design repose sur les performances mécaniques exceptionnelles des nanotubes de carbone. Les dispositifs sont modélisés dans un environnement fluide. Leur modélisation valide de façon préliminaire leur intérêt pour le suivi de durabilité.
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