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In the summer of 2017, the Système International de Référence Transfer Instrument (SIRTI) of the Bureau International des Poids et Mesures (BIPM) was hosted by the National Research Council of Canada (NRC) in Ottawa, Canada. This SIRTI visit was unique in many aspects. It was the first visit of the SIRTI to Canada. NRC was the first National Metrological Institute (NMI) to perform comparisons of four isotopes (⁹⁹ᵐTc, ¹⁸F, ⁶⁴Cu and ¹¹C) during a single two-week period. Finally, this was the first official measurement of ¹¹C in the SIRTI. The NRC had performed a primary standardization of ¹¹C in February of 2017 and calibrated its Secondary Standard Ionizing Radiation Chamber System (SSIRCS) in preparation for the SIRTI comparison. Two primary Liquid Scintillation methods (CIEMAT/NIST and TDCR) were employed and the results agreed. The stock material was received from a local cyclotron in the form of a¹¹C-labelled sodium acetate (NaC₂H₃O₂). Three ampoules were prepared for the purposes of comparison; one concentrated from the bulk material and two derived from a single dilution. Some inconsistency was evident due to a weighing problem for one of the ampoules containing the diluted solution, whose measurements were excluded from the analysis. The other two ampoules’ results were consistent within their respective uncertainties. The SIRTI was very stable and the final BIPM report will detail the stability checks, performance and behaviour of the SIRTI during its measurement campaign in Canada. There is still no Key Comparison Reference Value (KCRV) for ¹¹C as NRC is the first participant. However, during a test of the SIRTI at NPL in 2014, an equivalent SIRTI activity was measured as 9.87(5) kBq which was consistent with MonteCarlo predictions for ¹¹C in the SIRTI of 9.867(15) kBq. The NRC SIRTI equivalent activity for ¹¹C agrees within uncertainty with these results. This offers encouragement to other NMIs to request a¹¹C comparison given the consistency of experimental results from NRC and test results from the National Physical Laboratory, UK (NPL) and the BIPM. Finally a half-life measurement was determined from the NRC measurement of multiple half-lives of a ¹¹C ampoule and was found to be 20.332(40)min. From the SIRTI measurements at NRC, the half-life was derived as 20.328(13) min. This is smaller but consistent with the DDEP recommended value of 20.361(23)min., International Conference on Radionuclide Metrology, May 27-31, 2019, Salamanca, Spain

Successful aquaculture species are often chosen for their fast growth rates and fecundity, which are also characteristics of invasive species. The Pacific oyster Crassostrea gigas, which constitutes 80% of global oyster trade, has been confirmed as invasive in 17 of the 66 countries where it is cultured. The single study of its status in South Africa reported populations in six South Coast estuaries in 2001, dropping to three sites in 2003. We resurveyed these estuaries, visited others in the Eastern and Western Cape provinces, and sampled oyster tissue for molecular analyses of population structure. Pacific oysters have disappeared from Knysna and, following our collections, possibly also from the GouKou Estuary. Between 2003 and 2012, the Breede Estuary population decreased by 87%, from an estimated 184 206 to 23 760 individuals. Within this estuary, oysters 12 km upriver had denser shells and higher body condition indices than did those within 1.4 km of the river mouth, presumably reflecting higher availability of suspended organic matter. However, low salinity over most of the species’ range in the estuary probably inhibits recruitment. New populations of Pacific oysters in the Swartkops and Kaaimans estuaries urgently require monitoring and eradication. Haplotype (h) and nucleotide (π) diversities across all oyster populations sampled (h = 0.2300 [SD 0.0595], π = 0.0006 [SD 0.0007]) were lower than those of co-occurring indigenous Cape rock oysters Striostrea margaritacea from the GouKou and Breede estuaries (h = 0.9076 [SD 0.0386], π = 0.00589 [SD 0.00347]). Pacific oysters either have been introduced to South African estuaries infrequently, or have experienced genetic bottlenecks following river floods or human exploitation, or both. Populations growing outside culture infrastructure are restricted to estuaries in the Eastern and Western Cape provinces, with no evidence of occurrence in fully marine shelf environments. Given the species’ considerable socio-economic importance, estuarine and coastal surveillance coupled with aquaculture zoning are required to integrate biodiversity and food security considerations. Keywords: Cape rock oyster, habitat suitability, oyster invasivity, shell density

In the frame of Commission Mandate M/487 'Security standards', CEN/TC 391 assigned the highest priority to the standardisation of list-mode data, together with three other standardisation proposals. In response, the JRC ERNCIP Thematic Group on Radiological and Nuclear Threats to Critical Infrastructure described the state-of-the-art on list-mode data acquisition and proposed the basic elements of a standard data format. In addition, the RN Thematic Group conducted a survey addressed to users of digital data acquisition for nuclear instrumentation to investigate their needs with respect to the standardisation of the data format. This report presents the results of the survey, which will serve as an important input for the development of a preliminary draft standard that will accompany a New Work Item Proposal for a new international standard, to be submitted to the IEC in the frame of the EMPIR Project 14SIP07 'DigitalStandard', which will continue on the work initiated by the ERNCIP RN Thematic Group., JRC.D.4-Standards for Nuclear Safety, Security and Safeguards

This report deals with digital radiation detection systems employing list-mode data collection, which improves data analysis capabilities. Future data acquisition systems shall also ultimately enable the movement of detection data from first responders electronically to analysis centres rather than the costly and time consuming process of moving experts and/or samples. This new technology is especially useful in crisis events, when time and resources are sparse and increased analysis capacity is required. In order to utilise the opportunities opened by these new technologies, the systems have to be interoperable, so that the data from each type of detector can easily be analysed by different analysis centres. Successful interoperability of the systems requires that European and/or international standards are devised for the digitised data format. The basis of such a format is a list of registered events detailing an estimate of the energy of the detected radiation, along with an accurate time-stamp for recorded events (and optionally other parameters describing each event)., JRC.G.5-Security technology assessment

Strengthening CBRNE security in the European Union reduces the threat of and damage from CBRNE incidents. One of the main issues facing the EU security industry is its highly fragmented nature, exhibiting a lack of standardization and harmonised certification procedures. The need for standardised information exchange between competent authorities and international bodies regarding radiation measurements and data analysis has been recognised by several experts in response to Commission mandate M/487 for the establishment of European security standards. This report will suggest a way forward to develop protocols for more efficient cooperation between competent authorities and reachback centres at the national and international level. Not all EU Member States have the capabilities to process data provided by nuclear security instruments, and thus should consider instigating a coordinated capability yielding a more efficient and comprehensive approach in responding to future nuclear emergencies. This could be achieved by reachback centres across Europe (built upon existing national facilities and expertise) and would provide analysis services for alarm adjudication. Efficient data sharing and processing across EU Member States requires the use of standard data formats and protocols., JRC.G.5-Security technology assessment

Recent developments of digital data acquisition systems allow real-time pre-processing of detector signals at a high count rate. These so-called pulse processing digitizers are powerful and versatile instruments offering techniques which are important for nuclear security, critical infrastructure protection, nuclear physics and radiation metrology. Certain aspects of digital data acquisition affect the performance of the total system in a critical way and therefore require special attention. This report presents a short introduction to digital data acquisition, followed by a discussion of the critical parameters which affect the performance in the lab and in the field. For some of the parameters, tests are proposed to assess the performance of digital data acquisition systems. Good practices are offered to guide the selection and evaluation of digital data acquisition systems. More general performance criteria which are not specifically related to digital data acquisition systems are discussed separately., JRC.D.4-Standards for Nuclear Safety, Security and Safeguards