Search results for "010403 inorganic & nuclear chemistry"
showing 10 items of 141 documents
Modeling the sorption of Np(V) on Na-montmorillonite – effects of pH, ionic strength and CO2
2019
Abstract Results from batch type experiments were modeled using the 2 SPNE SC/CE model developed by Bradbury and Baeyens. This work focused on the applicability of this model to the sorption of Np(V) on Na-montmorillonite under high saline conditions (0.1–3.0 M NaCl) in the pH range of 2–10 and in the presence of dissolved CO2 (p(CO2) = 10−3.3 atm). Under ambient air conditions two additional surface complexation species had to be taken into account, which are ternary species involving one carbonate ligand (≡SONpO2(CO3)2−, ≡SONpO2(CO3)Na−). The gained set of complexation parameters was successfully tested over a wide range of Np(V) concentrations (10−4 to 10−12 M) under Ar atmosphere and am…
Determination of mass attenuation coefficient by numerical absorption calibration with Monte-Carlo simulations at 59.54 keV
2016
Abstract This study presents a numerical method in order to determine the mass attenuation coefficient of a sample with an unknown chemical composition at low energy. It is compared with two experimental methods: a graphic method and a transmission method. The method proposes to realise a numerical absorption calibration curve to process experimental results. Demineralised water with known mass attenuation coefficient ( 0.2066 cm 2 g − 1 at 59.54 keV) is chosen to confirm the method. 0.1964 ± 0.0350 cm 2 g − 1 is the average value determined by the numerical method, that is to say less than 5% relative deviation compared to more than 47% for the experimental methods.
Implementation of an aerodynamic lens for TRIGA-SPEC
2016
Abstract We report on the optimization of the gas-jet system employed to couple the TRIGA-SPEC experiment to the research reactor TRIGA Mainz. CdI2 aerosol particles suspended in N2 as carrier gas are used for an effective transport of fission products from neutron induced 235 U fission from the target chamber to a surface ion source. Operating conditions of the gas-jet were modified to enable the implementation of an aerodynamic lens, fitting into the limited space available in front of the ion source. The lens boosts the gas-jet efficiency by a factor of 4–10. The characterization of the gas-jet system as well as the design of the aerodynamic lens and efficiency studies are presented and …
Analysis of Roman and other archaeological glasses by 12 MeV proton activation analysis
2020
Abstract 14 elements were determined, at trace level, in Roman and other archaeological glasses by 12 MeV proton activation analysis. The results show that the natural glass from Mongolia and Brazilian quartz are the purest of all the samples analysed with detection limits at 1 ppm level for Ti, V, Cr, As, Sr, Y and Zr. In several cut pieces of one variety of Roman glass, using the concentration of Ca, Ti, Fe, Sr and Sb as markers, the homogeneity of glass production and their potential use in provenance studies were discussed.
Well GeHP detector calibration for environmental measurements using reference materials
2016
International audience; A well-type detector installed in the Modane underground Laboratory (LSM) can combine both low background and high detection efficiency and it is well suited for the analysis of small amounts of environmental samples. Reference materials such as IAEA-447 (moss-soil), IAEA-RG-Th1 and IAEA-RG-U1 were used for the detector calibration, owing to a chemical composition close to those of the environmental samples. Nevertheless , the matrix effects and the true coincidence summing effects must be corrected from the full energy peak efficiency (FEPE). The FEPE was performed for a wide range of energy by a semi-empirical method using Monte Carlo simulation (MCNP6), intended f…
Development of nuclear chemistry at Mainz and Darmstadt
2018
Abstract This review describes some key accomplishments of Günter Herrmann such as the establishment of the TRIGA Mark II research reactor at Mainz University, the identification of a large number of very neutron-rich fission products by fast, automated chemical separations, the study of their nuclear structure by spectroscopy with modern detection techniques, and the measurement of fission yields. After getting the nuclear chemistry group, the target laboratory, and the mass separator group established at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, a number of large international collaborations were organized exploring the mechanism of deeply inelastic multi-nucleon trans…
Comment on ‘Analysis of decay chains of superheavy nuclei produced in the 249Bk + 48Ca and 243Am + 48Ca reactions’
2018
Zlokazov and Utyonkov (2017 J. Phys. G: Nucl. Part. Phys. 44 075107) question the validity of the methods and conclusions presented by Forsberg et al (2016 Nucl. Phys. A 953 117). In this comment, we argue that the criticism is invalid.
Versatile use of ion beams for diffusion studies by the modified radiotracer technique
2004
Abstract In the modified radiotracer technique ion beams within a broad energy range are employed. They include energetic light particles ensuring radioactive isotope production via nuclear reactions, keV-ion implantation of radiotracers and sputtering by low energy heavy ions for depth profiling. If the involved ion–solid interactions are properly taken into account, the technique provides an effective means for solid-state diffusion studies under demanding conditions. The various aspects related to the modified radiotracer technique are surveyed and discussed. The reliability of the procedure is demonstrated by comparisons with corresponding profiles obtained by secondary ion mass spectro…
Production of plutonium tracers in 237Np nuclear reactions with 3He-ions in the energy range from 26 to 60 MeV
1998
Cross-sections for the reaction Np-237 + He-3 --> Pu-236,Pu-237,Pu-238 at He-3 bombarding energies from 26 to 60 MeV were measured. Thick-target yields, based on the measured and previously known cross-sections were constructed. The results are discussed and compared with Ether reactions leading to the formation of the same final nuclei. (C) 1998 Elsevier Science S.A.
Determination of distribution coefficients (Kd) of various radionuclides on UTEVA resin
2016
Abstract Using radioisotope markers the distribution coefficients (Kd) of the following elements In, Sn, Sb, Te, Bi, Co, Fe, Nb, Sr, Ba, Ag, Cd, Zr, Hf and Ti were determined with different concentrations of HCl, H2SO4 and HNO3 for the extraction chromatographic resin Uranium and TEtraValent Actinides (UTEVA). This data can be used for separation of elements in complex mixtures, as well as for correct assessment of the elements chemistry with higher valences such as 3, 4, 5 or 6.