ABSTRACT. Accelerator Mass Spectrometry (AMS) is by far the predominant technology deployed for radiocarbon tracer studies. Applications are widespread from archaeology to biological, environmental, and pharmaceutical sciences. In spite of its excellent performance AMS is expensive and complicated to operate. Consequently, alternative detection techniques for radiocarbon are of great interest, with the vision of a compact, user-friendly and inexpensive analytical method. Here we report on the use of intra-cavity optogalvanic spectroscopy (ICOGS) for measurements of the 14 C/ 12 C ratio. This new detection technique was developed by Murnick and co-workers (Murnick et al. 2008). In the infra-red (IR) region, CO 2 molecules have strong absorption coefficients. The IR-absorption lines are narrow in linewidth and shifted for different carbon isotopes. These properties can potentially be exploited to detect 14 CO 2 , 13 CO 2 or 12 CO 2 molecules unambiguously. In ICOGS, the sample is introduced as CO 2 gas, eliminating the graphitization step which is required in most AMS labs. In this paper, the status of the ICOGS setup in Uppsala is presented. The system is operational but not yet fully developed. Data are presented for initial results which illustrate the dependence of the optogalvanic signal on various parameters, such as background and plasma induced changes in the sample gas composition.
Occupational exposure to diisocyanates within the plastic industry causes irritation and disorders in the airway. The aim of this study was to develop, validate and characterize a method for the determination of 2,4-toluenediamine (2,4-TDA), 2,6-toluenediamine (2,6-TDA), 1,5-diaminonaphthalene (1,5-NDA) and 4,4'-methylenedianiline (4,4'-MDA) in hydrolysed urine and plasma, and to study the correlation between the plasma and urinary levels of these potential biomarkers of 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), 1,5-naphthalene diisocyanate (1,5-NDI) and 4,4'-methylenediphenyl diisocyanate (4,4'-MDI), respectively. Samples were hydrolysed with 0.3 M NaOH at 100 degrees C for 24 h. The diamines were extracted, derivatized with pentafluoropropionic acid anhydride, and quantified by selected ion monitoring on gas chromatography-mass spectrometry. The repeatability and reproducibility of the method were 7-18% and 7-19%, respectively. Dialysis experiments showed that the metabolites of 2,4-TDI, 2,6-TDI, 1,5-NDI and 4,4'-MDI in plasma were exclusively protein adducts. No free diamines were found in urine, indicating that all diisocyanate-related metabolites were in a conjugated form. For each diisocyanate-related biomarker, there were strongly significant correlations (p<0.001) between individual levels of metabolites in plasma and urine, with Spearman's rank correlation coefficient (rs) values of 0.74-0.90. The methods presented here will be valuable for the development of biological monitoring methods for diisocyanates.
The European Lead-Cooled Training Reactor (ELECTRA) has been proposed as a training reactor for fast systems within the Swedish nuclear program. It is a low-power fast reactor cooled by pure liquid lead. In this work, we propagate the uncertainties in 239 P u transport data to uncertainties in the fuel inventory of ELECTRA during the reactor life using the Total Monte Carlo approach (TMC). Within the TENDL project the nuclear models input parameters were randomized within their uncertainties and 740 239 P u nuclear data libraries were generated. These libraries are used as inputs to reactor codes, in our case SERPENT, to perform uncertainty analysis of nuclear reactor inventory during burn-up. The uncertainty in the inventory determines uncertainties in: the longterm radio-toxicity, the decay heat, the evolution of reactivity parameters, gas pressure and volatile fission product content. In this work, a methodology called fast TMC is utilized, which reduces the overall calculation time. The uncertainty in the long-term radiotoxicity, decay heat, gas pressure and volatile fission products were found to be insignificant. However, the uncertainty of some minor actinides were observed to be rather large and therefore their impact on multiple recycling should be investigated further. It was also found that, criticality benchmarks can be used to reduce inventory uncertainties due to nuclear data. Further studies are needed to include fission yield uncertainties, more isotopes, and a larger set of benchmarks.
Abstract. Numerous domains, in fundamental research as well as in applications, require the study of reactions induced by neutrons with energies from few MeV up to few tens of MeV. Reliable measurements also are necessary to improve the evaluated databases used by nuclear transport codes. This energy range covers a large number of topics like transmutation of nuclear waste, design of future fission and fusion reactors, nuclear medicine or test and development of new detectors. A new facility called Neutrons For Science (NFS) is being built for this purpose on the GANIL site at Caen (France). NFS is composed of a pulsed neutron beam for time-of-flight facility as well as irradiation stations for cross-section measurements. Neutrons will be produced by the interaction of deuteron and proton beams, delivered by the SPIRAL-2 linear accelerator, with thick or thin converters made of beryllium or lithium. Continuous and quasi-mono-energetic spectra will be available at NFS up to 40 MeV. In this fast energy region, the neutron flux is expected to be up to 2 orders of magnitude higher than at other existing time-of-flight facilities. In addition, irradiation stations for neutron-, proton-and deuteron-induced reactions will allow performing cross-section measurements by the activation technique. After a description of the facility and its characteristics, the experiments to be performed in the short and medium term will be presented.
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