BENEFITS OF TIME CORRELATION MEASUREMENTS FOR PASSIVE SCREENING

The “FLASH Portals Project” is a collaboration between Arktis Radiation Detectors Ltd (CH), the Atomic Weapons Establishment (UK), and the Joint Research Centre (European Commission), supported by the Technical Support Working Group (TSWG). The program’s goal was to develop and demonstrate a technology to detect shielded special nuclear materials (SNM) more efficiently and less ambiguously by exploiting time correlation. This study presents experimental results of a two-sided portal monitor equipped with in total 16 4He fast neutron detectors as well as four polyvinyltoluene (PVT) plastic scintillators. All detectors have been synchronized to nanosecond precision, thereby allowing the resolution of time correlations from timescales of tens of microseconds (such as (n,alpha) reactions) down to prompt fission correlations directly. Our results demonstrate that such correlations can be detected in a typical radiation portal monitor (RPM) geometry and within operationally acceptable time scales, and that exploiting these signatures significantly improves the performance of the RPM compared to neutron counting. Furthermore, the results show that some time structure remains even in the presence of heavy shielding, thus significantly improving the sensitivity of the detection system to shielded SNM.JRC.E.8-Nuclear securit

FLASH portals: radiation portal monitor SNM detection using time correlation techniques

No abstract available

FLASH Portals: Radiation Portal Monitor SNM Detection using Time Correlation Techniques

The "FLASH Portals Project" is a collaboration between Arktis Radiation Detectors Ltd (CH), the Atomic Weapons Establishment (UK), and the Joint Research Centre (European Commission), supported by the Technical Support Working Group (TSWG). The program's goal was to develop and demonstrate a technology to detect shielded Special Nuclear Materials (SNM) more efficiently and less ambiguously by exploiting time correlation. This study presents experimental results of a two-sided portal monitor equipped with 16 He-4 fast neutron detectors as well as 4 polyvinyltuolene (PVT) plastic scintillators. All detectors have been synchronized to ns precision, thereby allowing to resolve time correlations from timescales of tens of microseconds (such as (n,γ) reactions) down to prompt fission correlations directly. Our results demonstrate that such correlations can be detected in a typical RPM geometry and within operationally acceptable time scales, and that exploiting these signatures significantly improves the performance of the RPM compared to neutron counting. Furthermore, the results show that some time structure remains even in the presence of heavy shielding, thus significantly improving the sensitivity of the detection system to shielded SNM.JRC.E.8-Nuclear securit

Hydrological modelling

This chapter deals primarily with hydrological flood modelling. Its history began in the mid-nineteenth century with the ‘Rational Method’ for peak flows attributed to Thomas Mulvany. Many different models have been developed, varying greatly in scope and level of detail, and are used for different purposes including science-driven testing of ideas to problem-oriented applied studies. But all represent greatly simplified analogies or visions of the real world. The chapter is concerned with non real-time flow forecasting. It follows a broad classification of models of increasing complexity into metric-, conceptual- and physics-based. The simplest are black-box, data-driven or metric models, which rely solely on observed relationships and have limited or no representation of physical processes. A generation of topographically oriented models has evolved, starting from TOPMODEL to more recent models such as TOPKAPI and Grid-to-Grid which achieve a parsimonious representation of the dominant component processes