RESUMEN
The radioxenon measurement components of the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) play a significant role in uncovering clandestine nuclear weapons tests. The radioxenon network coverage is a critical component of the IMS capabilities. NEX48 is one of the still to-be-certified radioxenon stations and it will be the only IMS station with radioxenon measurement capabilities in the Sahara desert in Central Africa. Therefore, it may increase the radioxenon global coverage in a vast region. Seasonal contributions from NEX48 (in Niger) on the 133Xe global coverage of the IMS have been investigated in current and complete (39 stations) networks for a hypothetical one-kt subsurface nuclear explosion using atmospheric transport modelling. Adding NEX48 to the stations currently operating increased the daily global coverage by about 1.1 percent on average with most of the improvement between 15-45 N latitudes and 0-40 E longitudes. The improvements from adding NEX48 vary greatly by the seasons of the year. Removing NEX48 from the complete network leads to a daily coverage deterioration of about 0.2 percent, and the cumulative minimum coverage has a significant change.
Asunto(s)
Contaminantes Radiactivos del Aire , Monitoreo de Radiación , Contaminantes Radiactivos del Aire/análisis , Cooperación Internacional , Niger , Radioisótopos de Xenón/análisisRESUMEN
The radionuclides part of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) global network of International Monitoring System (IMS) is based on the measurement of particles and radioactive noble gases. Forty radionuclide stations are going to be equipped with radioxenon measurement components to monitor the nuclear explosion signatures around the world. Global coverage of the noble gas IMS stations has been investigated using atmospheric transport modelling. Two years of worldwide release for a hypothetical 1-kt underground nuclear explosion and detection of 133Xe in the IMS radioxenon station locations are considered. The present and completed status were supposed as two different scenarios to estimate the daily coverage of the network. The calculated quantities were evaluated corresponding to the whole latitude/longitude grid in image-base and numerical patterns. Although the fluctuation of daily coverage is varying in time, the cumulative minimum amounts were indicated that North America has stable high coverage in the present arrangement. Moreover, after the completion of the network, this aspect will be expanded to the middle part of the Northern Hemisphere as well as the west region of the Southern Hemisphere. Finally exploring the cumulative maximum daily coverage is denoted that adding the non-operational stations to the current network has a great influence on the 20 S - 90 N latitudes to 0-180 W longitudes and about 50% effect on the network coverage (NC) of the north of Europe, South Atlantic, and Oceania. However, it has almost no impact on the values of the limited area around the middle east part of the Pacific Ocean.
Asunto(s)
Contaminantes Radiactivos del Aire , Monitoreo de Radiación , Contaminantes Radiactivos del Aire/análisis , Cooperación Internacional , Radioisótopos , Radioisótopos de Xenón/análisisRESUMEN
LiF:Mg,Cu,Ag is a new dosimetry material that is similar to LiF:Mg,Cu,P in terms of dosimetric properties. The effect of the annealing temperature in the range of 200 to 350°C on the thermoluminescence (TL) sensitivity and the glow curve structure of this material at different concentrations of silver (Ag) was investigated. It has been demonstrated that the optimum values of the annealing temperature and the Ag concentration are 240°C and 0.1 mol% for better sensitivity, respectively. The TL intensity decreases at annealing temperatures lower than 240°C or higher than 240°C, reaching a minimum at 300°C and then again increases for various Ag concentrations. It was observed that the glow curve structure altered and the area under the low temperature peak as well as the area under the main dosimetric peak decreased with increasing annealing temperature. The position of the main dosimetric peak moved in the direction of higher temperatures, but at 320 and 350°C annealing temperatures, it shifted to lower temperatures. It was also observed that the TL sensitivity could partially be recovered by a combined annealing procedure.