[en] A series of cationic, zwitterionic and anionic carbocyanine dyes have been measured with TOF-SIMS under Ga⁺ bombardment. In contrast to the cationic dyes, which give very intense molecular ion and characteristic fragment signals in the positive mode, the anionic dyes produce only a few fragment signals of low intensity. Even in the negative mode no molecular ions of the anionic dyes are seen in the recorded spectra. Actually, none of the studied molecules produces negative SIMS spectra containing molecular information. A comparative study was made between TOF-SIMS and other mass spectrometric techniques, namely, fast atom bombardment (FAB), electro spray ionization (ESI) and matrix assisted laser desorption ionization (MALDI). The measurements show that MALDI, ESI as well as FAB all give rise to spectra containing molecular ion signals, either in the positive, in the negative or in both modes. Unlike with TOF-SIMS, this observation also applies to the anionic dyes. Characteristic fragments of the dyes are present in all the recorded spectra. However, TOF-SIMS appears to induce more fragment ions in comparison with the other techniques. ESI, for instance, produces hardly any molecular fragments. Finally, the kind of fragment ions recorded depends upon the technique used, though some signals are produced by various techniques. For these carbocyanine dyes there is no clear correlation between the mass spectra obtained with TOF-SIMS and spectra obtained with the other techniques. This points to different desorption/ionization mechanisms, and makes it difficult, in practice, to make predictions on the feasibility of TOF-SIMS, starting from results of the other MS techniques

[en] This poster describes how SCK-CEN teams determine the burnup of UO_2 and MOX fuels. In radiochemistry, burnup is expressed as FIMA (Fissions per Initial Metal Atom) and is calculated as the number of fissions relative to the number of heavy metal atoms initially present in the fuel. This last value is the sum of the number of fissions and the number of heavy atoms at the end of irradiation (as measured). The number of heavy atoms at the end of irradiation can be determined with Thermal Ionization Mass Spectrometry (TIMS) and radiochemical techniques, while the number of fissions can be derived from a fission product monitor for which the concentration in the fuel is proportional to the number of heavy atoms fissioned. Commonly used burn-up monitors are several Nd isotopes and the gamma emitters "1"3"7Cs and "1"4"4Ce. Depending on the chosen burn-up monitor, this can be determined by either radiochemical methods or mass spectrometry. First, fuel samples are dissolved in a hot-cell employing a multi-step procedure in order to successfully separate if from the cladding and obtain complete dissolution. Afterwards, a first aliquot of dissolved sample is used for alpha and gamma spectrometry, while other aliquots are dedicated for TIMS analyses. Complex chemical separations are needed in order to separate base actinides, minor actinides and the many fission products. Moreover, each technique requires specific sample preparation. SCK-CEN teams have gained experience with the burnup determination of commercial NPP spent fuels and of experimental reactor fuels in the framework of the HEU/LEU conversion

[en] Metal-assisted (MetA) SIMS using the deposition of a thin Au or Ag layer on non-conducting samples prior to analysis has been advocated as a means to improve the secondary ion (S.I.) yields of organic analytes. This study focuses on the influence of time and temperature on the yield enhancement in MetA-SIMS using thick layers of poly(vinylbutyral-co-vinylalcohol-co-vinylacetate) (PVB) containing dihydroxybenzophenone (DHBPh) or a cationic carbocyanine dye (CBC) and spin-coated layers of the cationic dye on Si. Pristine samples as well as Au- and Ag-coated ones were kept between -8 deg. C and 80 deg. C and analysed with S-SIMS at intervals of a few days over a period of 1 month. The yield enhancement was found to depend strongly on the kind of evaporated metal, the storage temperature and time between coating and analysis

[en] This work describes the development and optimization of the radiochemical separation of ¹⁴⁷Pm and ¹⁵¹Sm. The two main challenges addressed were: the radiochemical separation of the lanthanides by using LN Resin and DGA,N Resin, and the quantification of the chemical recovery of ¹⁴⁷Pm with a non-isotopic analogue (i.e. neodymium). The applicability of radiochemical separation procedures was investigated by using spiked samples. The optimized radiochemical separation procedure by using LN Resin was applied to a reactor cooling water primary coolant sample with an automated system. Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) was used to determine the chemical recoveries. (author)

[en] The European Nuclear Young Generation Forum (ENYGF) is the event organised every 2 years within the European Nuclear Society - Young Generation Network (ENS-YGN) for European young professionals and students. It consists in 3 days of conferences (plenary sessions, workshops, panel sessions, technical and poster session), 1 day of technical tours and 1 day of cultural visits. ENYGF 2015 is dedicated to the dual aspect of the relationship between nuclear power and environment: the impact of nuclear activities on the environment and the contribution of nuclear energy to fight climate change. A great deal of this document is composed of the slides of the presentations