During recent online gas-phase experiments with the transactinide elements copernicium (Cn, Z = 112) and flerovium (Fl, Z = 114), the transport of a volatile astatine species was observed. Comprehensive Monte Carlo simulations of the deposition pattern of At-211 on the given quartz, selenium, and gold chromatographic surfaces were carried out, and the corresponding adsorption enthalpies were estimated. Based on the astatine speciation from previous model experiments, the compound observed in this work was ascribed to AtOH/HAtO. The herein presented results assist in paving the way toward a future chemical characterization of tennessine (Ts, Z = 117) with similar gas adsorption chromatography techniques.

The drift behavior of charge carriers, generated by alpha-particles of a reference Am-241-source, in electronic grade, single crystal chemical vapor deposition (scCVD) diamond was investigated by the transient current technique (TCT) from room temperature up to approximate to 473 K. Furthermore, the alpha-spectroscopic behavior was analyzed in terms of charge collection and spectroscopic resolution for the same temperature range. All conducted measurements revealed complete charge collection up to the maximum temperature. The electron-hole-pair creation energies were derived from the TCT as well as from the spectroscopic measurements. The herein presented results imply that high temperature alpha-spectroscopy with diamond-based semiconductor solid state detectors, using presently available scCVD sensor substrates, is feasible at least up to 473 K. Only at the highest applied temperature, the conducted TCT measurements showed distorted signal traces, indicating a uniform positive space charge built-up.

When considering f elements, solvent extraction is primarily used for the removal of lanthanides from ore and their recycling, as well as for the separation of actinides from used nuclear fuel. Understanding the complexation mechanism of metal ions with organic extractants, particularly the influence of their molecular structure on complex formation is of fundamental importance. Herein, we report an extraordinary (up to two orders of magnitude) change in the extraction efficiency of f elements with two diastereomers of dimethyl tetraoctyl diglycolamide (Me2 -TODGA), which only differ in the orientation of a single methyl group. Solvent extraction techniques, extended X-ray absorption fine structure (EXAFS) measurements, and density functional theory (DFT) based ab initio calculations were used to understand their complex structures and to explain their complexation mechanism. We show that the huge differences observed in extraction selectivity results from a small change in the complexation of nitrate counter-ions caused by the different orientation of one methyl group in the backbone of the extractant. The obtained results give a significant new insight into metal-ligand complexation mechanisms, which will promote the development of more efficient separation techniques.

The properties of graphite samples from the thermal column of a material testing reactor and from the internals of two different nuclear power reactors were investigated regarding the thermal release of tritium and radiocarbon. These reactor types have been selected due to the different conditions under which graphite has been irradiated with neutrons during the operating time of these reactors. Based on the findings, options for thermal treatment of irradiated graphite are discussed in order to facilitate its final disposal. (C) 2013 Elsevier B.V. All rights reserved.