Activity ratios of CTBT-relevant isotopes can be used to discriminate nuclear explosion sources from releases of nuclear facilities and to determine the detonation time under assumed scenarios. The net signals of radioxenon isotopes and their associated uncertainties are estimated by the net count calculation (NCC) method. An alternative approach is the regression analysis such as the least...
The radioxenon system gain stability is critical to provide accurate measurements of the activity. There are several different methods for processing daily quality control (QC) beta-gamma two-dimensional (2-D) spectra for checking energy calibration. Fitting to a template seems the most correct method for monitoring the calibration stability. The possibility of using a template for a 2-D...
In this study, we develop a new radioxenon detection system based on beta-gamma coincidence to improve the sensitivity of detection in laboratory analysis. The designed system is a new prototype that is tested by injecting the 222Rn and its daughters (214Pb and 214Bi) as a beta–gamma emitter and also Xe-131m gaseous sources, which are in the interest of CTBTO. Further, the system is calibrated...
One of the main challenges for the Comprehensive Nuclear-Test-Ban Treaty Organization verification regime is to be able to discriminate anomalous signals generated by underground nuclear explosions (UNEs) from those generated by other sources like medical isotope production facilities (MIPFs) and nuclear power plants (NPPs). The general method can consist in a procedure starting with the...
Atmospheric aerosol collection using electrostatic precipitation (ESP) promises power consumption roughly one order of magnitude lower than filter paper based collection methods. For monitoring radionuclides in the atmosphere, this translates to an order of magnitude improvement in system sensitivity for the same power consumed. Conversely, small portable systems are enabled with lower battery...
Creare has designed, built, and tested an electrostatic precipitator (ESP) collection system for integration into the next generation of monitoring stations, RASA 2.0. The new system design has several significant improvements including advanced detectors, increased particle collection efficiency, lower power consumption, and potentially shorter collection times. Our advanced two stage ESP...
The radionuclide network of the International Monitoring System (IMS), operated by the Comprehensive Nuclear-Test-Ban Treaty (CTBT) Organization, is comprised of particulate and noble gas analysis. A variety of spectroscopic techniques have been developed and are in use to identify radionuclides which may be indicative of a nuclear explosion. Ongoing efforts to increase the sensitivity of...
Recent developments of noble gas systems include new detector technologies. They exhibit very low background count rates. In this case, radioxenon signal as low as a few counts per day is expected. Therefore, for such low count measurements, classical Currie law estimation for measurement detection threshold and detection limits are not accurate enough. In this context, the CEA/DAM implemented...
Xenon spikes measurement is a key factor for Xe equipment calibration and a quality assessment/quality control programme for noble gas cluster. It is very important to have four Xe isotopes at the spike samples (Xe-131m, Xe-133, Xe-133m, Xe-135). The spikes are produced by contractors organized by the Comprehensive Nuclear-Test-Ban Treaty Organization. Unfortunately, due to very short half...
There are several methods for analysis of radioxenon beta-gamma coincidence spectra. The most important approaches to estimating the activity using beta-gamma coincidence spectra are the Net Count Calculation (NCC) and the Standard Spectrum Method (XeMat and ROI simultaneous fitting method). Within these approaches, algorithms differ in many ways and can provide different estimates of the...
Recent reports have shown that unusual xenon radionuclides can show up in grown based xenon detection systems that lead to false hits on all four of the regularly monitored radionuclides (Xe-135, Xe-133, Xe-133m, Xe-131m). Potential sources of these unusual radionuclides could be high flux neutron sources or spallation neutron sources that are operated in the vicinity of current ground based...
The CTBT-relevant radionuclides were selected using decay data from around 1998 to 2000. Now, about 22 years after the selection, we have available evaluated decay data that are even more reliable than they were at that time. The latest evaluated decay data (half-lives, decay modes, γ-ray energies, and their emission rates) for the CTBT relevant 96 radionuclides and background 49 radionuclides...
Gamma-gamma coincidence techniques are known to improve the detection of particulate radionuclides relevant for Treaty monitoring purposes. To that end, Pacific Northwest National Laboratory (PNNL, USA) has developed a novel γ-γ coincidence analysis and radionuclide quantification software package. The software’s execution has been tested for radionuclides relevant to Comprehensive...
Field studies of underground gas migration are an essential component of ongoing research to better understand how radioactive materials produced from underground nuclear explosions transport through and escape from the subsurface. Considerable research has been made in the past on understanding long term gas migration behavior driven by natural processes at field sites, but in recent years a...
As the new generation of International Monitoring Systems (IMS) stations radioxenon are being deployed, the radionuclide laboratories are seeing an increase in samples sent for reanalysis. These samples include both radioxenon spikes and environmental backgrounds. Additionally, the sample volumes have increased with the new systems to further improve the minimum detectable concentrations. We...
The purpose of a radionuclide expert technical analysis (ETA-RN) is to assist States Parties to identify the source of a specific event. The output of an ETA-RN is a State Requested Methods Report (SRMR), which builds on routinely generated results from standard International Data Centre products like the radionuclide reviewed report and radionuclide laboratory report. The various...
A new goal for radionuclide monitoring is inspired by what is done with waveform processing, to automatically create a radionuclide event bulletin, synthesized from multiple measurements across the radionuclide network. Network measurements are sequentially processed through detection, association, and finally assimilated in an event, which is then documented within a bulletin with supporting...
A methodology of particle grouping based on a mathematical model enables to induce manipulation of the particle size distribution using grouping and coagulation which leads, in turn, to the increase of filtration efficiency and detection ability of monitoring systems.
This study was conducted as a combined theoretical and experimental one. The current prototype consists of an inlet of...
Fires are still a large concern in several countries due to the social, environmental and economic damages they cause. Computer vision is focusing a lot of their attention on improving object detection as one of the fundamental challenges in the field. The aim of this research is to propose a system to predicate or to detect a fire accident in an on-site inspection area in real time using a...
The CTBTO International Data Centre (IDC) developed a novel Geant4 based Monte Carlo simulation software for HPGe detectors in use at particulate systems of the International Monitoring System (IMS). The software, dubbed GRANDSim (an acronym for Geant4-based RAdioNuclide Detector Simulation tool), allows to simulate both coaxial and planar detectors, and includes default definitions of...
One of the most important issues in radionuclide monitoring technology is the analysis of radionuclide data of the International Monitoring System (IMS). The number and concentration rate of CTBT-relevant detected radionuclides determine the possibility of a nuclear event occurrence in radionuclide monitoring. Fission and activation products being on the standard list of CTBT-relevant...
GBL15, the UK’s noble gas certified Comprehensive Nuclear-Test-Ban Treaty Organization's radionuclide laboratory, supports the International Monitoring System (IMS) through the measurement of environmental radioxenon samples using beta-gamma coincidence spectrometry. GBL15 currently utilizes a system comprised of NaI(Tl) photon detectors and plastic scintillator electron-detectors in a SAUNA...
An important aspect of on-site inspection (OSI) is a rigid chain of custody, where the risk of human error is minimized. Since 2016, FOI has conducted four field campaigns in Kvarntorp (Sweden), with the aim of understanding the radioactive xenon background in uranium-rich soil. During these campaigns, we have developed methodologies for sample collection and analysis. During the most recent...
A chain of custody (COC) is required in many laboratories that must analyse forensic materials and also to assure reliability of reported results. Tracking a reliable COC during an on-site inspection can be laborious but it is mandatory as it must assure that the evidence is authentic and traceable. The sampling methodology of the material, its transport and all the analysis steps as well...
Samples from International Monitoring System (IMS) stations which contain multiple CTBT-relevant radionuclides with abnormal activity concentrations (Level 5 for particulates) are sent to IMS radionuclide laboratories for further analysis. Since a reanalysis of spectra at IMS radionuclide laboratories might enhance the reliability of analysis results, it is proposed to investigate a method...
For the enhancement of International Data Centre products, specifically, the Standard Screened Radionuclide Event Bulletin (SSREB), an important step is to establish methods to associate the detections of CTBT-relevant nuclides in different samples with the same release to characterize its source for the purpose of nuclear explosion monitoring. Episodes of anomalous activity concentrations at...
The isotopic ratios of radioxenon can be useful for discrimination between CTBT-relevant radioxenon detections and civil nuclear facilities. In this presentation, the isotopic ratio distributions of emissions from the civil nuclear facilities, are evaluated first in order to test and demonstrate this methodological approach. Second, the source-receptor sensitivity fields calculated...
Environmental radioxenon measurements for nuclear explosion monitoring use the net count method to determine activity concentrations and rely on detector sensitivities for each of the radioxenon isotopes. This method requires that a detector background measurement be made to account for environmental radioactivity and is only performed during the initial install or during a recalibration....
The ability to evaluate the concentrations of radioactive noble gases in the atmosphere is very important because it represents a powerful early warning tool in the event of a nuclear accident. Since there are currently no laboratories capable of carrying out this type of assessment in our country, a specific system has been set up for sampling, concentration, separation and analysis of...
Recent studies emphasize neutron activation as a source of radioxenon emission which needs to be considered as contributing to the atmospheric radioxenon background. Since activation products have different isotopic ratios than radioxenon from fission, taking activation into consideration impacts on the determination of the origin of radioxenon detected by the International Monitoring System....
Radioxenon is used to identify underground nuclear explosions by quantifying the amount and isotopic ratios of Xe-135, Xe-133, Xe-133m, and Xe-131m. Determining these concentrations requires knowledge of the detector performing the measurement and the accurate attribution of each measured decay. The current standard for estimating the activity concentration employs a beta/gamma coincidence...
Operated by the Comprehensive Nuclear-Test-Ban Treaty Organization, the International Monitoring System is used by almost 200 nations to monitor for nuclear weapons tests. After more than 20 years, the network is mostly complete, however the technology utilized for the particulate monitoring component remains practically the same, despite a number of laboratories developing coincidence systems...
This work presents the results of the development and experimental investigations of the sampling unit of the automated system for monitoring the Ar-37 content in the soil and the surface atmosphere. The adsorption and separation characteristics of materials for air separation and argon extraction from an air sample by the volumetric method have been studied. CaA (5A), PSA/VPSA (13XHP) NaX...
An on-site inspection (OSI) could be triggered in any environment. Environmental factors affect not only the signatures and observables of a nuclear explosion, but also the performance of the inspection team. Pursuant to the work on the OSI Action Plan 2016-2019 Project 1.5 on Operationalization of OSIs in Different Environments, this poster summarizes typical nuclear test explosion scenarios,...
Radiation early warning systems (REWS), which continuously transmit information about the level of radiation background, volumetric activity of radionuclides, meteorological conditions and other measured parameters to the central control post, can significantly reduce the risks of radiation threats to the population in controlled areas. The structure and composition of the existing REWS in...
Measuring radionuclide releases from underground nuclear explosions is extremely challenging given the likely low release and increasing background releases. This becomes even more challenging when measurement uncertainties are not fully understood and can make decisions based on measurements questionable. The work presented here will lay out a holistic uncertainty model that includes terms...
Lessons learned from 20 years of operation of the International Monitoring System for aerosol sampler/analysers have pointed the way to a new generation of aerosol monitoring equipment. Using new technology and following the sampling/analysis scheme developed for next generation xenon systems, new aerosol equipment will be more resilient in power failures, will give much better location in...
Isotopes of radioxenon are prevalent in the atmosphere and present a “background” signal which can make radioxenon detection analysis and event reconstruction analysis more difficult. In recent years advances in software have allowed for Bayesian reconstruction techniques to be applied to radionuclide detections to determine the source parameters. This work focusses on the effort to...
Sonicona was contracted by the CTBTO to explore processing methods for the development of on-site inspection resonance seismometry capabilities. The motivation is to analyse seismic earthquake recordings to detect any anomalies indicative for a cavity or rubble zone caused by an underground nuclear explosion. We have developed the onset-delay method for strong earthquakes from regional to...
The world´s first radioxenon array has successfully been installed in Sweden. The array consists of five detecting sensors (SAUNA Qb) which have been in operation for about two years. Compared to other radioxenon systems, the units are less expensive and easier to install and maintain. The cost of the entire array is similar to one single state of the art system. The individual sensors are...
A SAUNA xenon lab system is operated at the Swedish xenon laboratory. The system has been running since 2009 and is used for a large variety of samples, ranging from subsoil samples with stable xenon volumes as low as 0.1 ml up to samples from the SPALAX-NG systems with a xenon volume of up to 6 ml. The high dynamic range of sample sizes puts special demands on the performance stability and...
The International Monitoring System radionuclide particulate systems of the CTBTO network are equipped with one of the following three system types: CINDERELLA, RASA and manual. Each system commonly involves sampling, decaying and acquisition processes. Whereas the entire processes are automatically conducted in both the CINDERELLA and the RASA systems, ensuring high reproducibility of the...
Prior efforts in developing a silicon beta cell as a potential improvement to scintillating plastic in beta-gamma systems resulted in a design with high resolution, capable of resolving different conversion electron energies in the metastable radioxenons, but a higher threshold that cut off low energy X rays. Switching from a photomultiplier tube based NaI well detector to a low-voltage...
For the Source Term Analysis of Xenon (STAX ) project an experimental network to measure releases of radioxenon isotopes at the stack of nuclear facilities is being set up. The data are transmitted to a central server, where authorized users can retrieve raw data from the STAX server or can view the data via a web browser. In this presentation an overview on the various interactive data...
Noble gas processes are based on the use of adsorbent materials. Among them, silver-exchanged zeolites are the most efficient for Xe extraction. Before the use of a material in processes, it is crucial to ensure its performance, especially when use in systems operating 24/7. Ag-ZSM-5 (one of the studied exchanged zeolite) is an efficient candidate to enrich Xe, but long term stability seems to...
The On-Site Inspections (OSI) are the final verification regime of CTBT. Its principal purpose is to detect if an underground nuclear explosion (UNE) has been carried out. Several geophysical techniques are used on a suspicious area to detect cavities, holes or devices that indicate the realization of a nuclear essay. One of these techniques is seismic reflection. There is scarce information...
Normal operational releases of radioxenon make the discrimination between radioxenon detections from civil nuclear applications and from nuclear testing a very complex task.
The objective for the short to medium term is to develop algorithms and tools that facilitate the understanding of the background. The longer term vision is to eventually develop robust methodologies for explaining to...
Radioxenon monitoring systems are a crucial component of the International Monitoring System (IMS) for the verification of the Comprehensive nuclear-Test-Ban Treaty. They monitor the atmosphere for potential xenon releases originating from nuclear tests. The efficient collection and purification of xenon from air is essential for their detection capability. The first systems in the IMS used...
Xenon International is a next generation radioxenon monitoring system that was developed at PNNL and being manufactured at Teledyne Brown Engineering (TBE) to strengthen nuclear test monitoring and has recently completed Provisional Technical Secretariat (PTS) testing and was accepted as a qualified system for the International Monitoring System (IMS). Xenon International processes samples...
