RESUMO
Many of the moving components in accelerator and target environments require lubrication. Lubricants in such environments are exposed to high fluxes of secondary radiation, which originates from beam interactions with the target and from beam losses. The secondary radiation is a mix of components, which can include significant fractions of neutrons. Lubricants are radiation-sensitive polymeric materials. The radiation-induced modifications of their structure reduce their service lifetime and impose additional facility maintenance, which is complicated by the environmental radioactivity. The study of the lubricants radiation resistance is therefore necessary for the construction of new generation accelerators and target systems. Nevertheless, data collected in mixed radiation fields are scarce. Nine commercial greases were irradiated at a TRIGA Mark II Research Reactor to serve for the construction of new accelerator projects like the European Spallation Source (ESS) at Lund (Sweden) and Selective Production of Exotic Species (SPES) at Legnaro, (Italy). Mixed neutron and gamma doses ranging from 0.1 MGy to 9.0 MGy were delivered to the greases. For an experimental quantification of their degradation, consistency was measured. Two of the greases remained stable, while the others became fluid. Post-irradiation examinations evidence the cleavage of the polymeric structure as the dominant radiation effect. Dose and fluence limits for the use of each product are presented. Apart from the scientific significance, the results represent an original and useful reference in selecting radiation resistant greases for accelerator and target applications.
RESUMO
The commerce of illegal and counterfeit medicinal products on internet is a serious criminal problem. Drugs for erectile dysfunction such as phosphodiesterase type 5 inhibitor are the most commonly counterfeited medicines in Europe. The search of possible toxic chemical substances in seized products is needed. Moreover, the profiling of the material can be the source of relevant forensic information. For the first time a combined approach based on liquid chromatography (LC) coupled to high resolution mass spectrometry (HRMS) and instrumental neutron activation analysis (INAA) is proposed and tested, allowing characterisation of both authentic and illegal pharmaceuticals containing sildenafil seized in Italy. LC-HRMS allowed the detection and identification of unknown impurities not reported on labels in illegal products and the quantitation of the sildenafil. INAA showed to be suitable to provide both qualitative and quantitative information for forensic purposes on 23 elements, allowing discrimination between legal and illegal products.
