Comprehensive Test Ban Treaty Organization Research Articles

Attracting a crowd: What societal verification means for arms control

The idea that ordinary people might contribute to verification of arms control treaties is not new; abstract discussions of the concept date back decades. But powerful and portable electronic devices have spread so widely in recent years that societal verification now seems an imminent reality. Motivated individuals might, for instance, collect treaty-relevant data through onboard sensors that smartphones can carry and then transmit the information to multilateral verification bodies or, as is already happening, share it online with global communities that subject it to crowdsourced analysis. But will societal verification generate enthusiasm in the developed and developing worlds alike? What legal protections must be established for participants? And will information gathered through societal verification ultimately prove useful and trustworthy? Three authors explore these emerging questions: from Burkina Faso and representing the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization, Lassina Zerbo (2013); from the United States, research fellow Nima Gerami; and from Malaysia, nuclear engineer Jamal Khaer Ibrahim (2013).

Attracting a crowd: What societal verification means for arms control

The idea that ordinary people might contribute to verification of arms control treaties is not new; abstract discussions of the concept date back decades. But powerful and portable electronic devices have spread so widely in recent years that societal verification now seems an imminent reality. Motivated individuals might, for instance, collect treaty-relevant data through onboard sensors that smartphones can carry and then transmit the information to multilateral verification bodies or, as is already happening, share it online with global communities that subject it to crowdsourced analysis. But will societal verification generate enthusiasm in the developed and developing worlds alike? What legal protections must be established for participants? And will information gathered through societal verification ultimately prove useful and trustworthy? Three authors explore these emerging questions: from Burkina Faso and representing the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization, Lassina Zerbo; from the United States, research fellow Nima Gerami (2013); and from Malaysia, nuclear engineer Jamal Khaer Ibrahim (2013).

Attracting a crowd: What societal verification means for arms control

The idea that ordinary people might contribute to verification of arms control treaties is not new; abstract discussions of the concept date back decades. But powerful and portable electronic devices have spread so widely in recent years that societal verification now seems an imminent reality. Motivated individuals might, for instance, collect treaty-relevant data through onboard sensors that smartphones can carry and then transmit the information to multilateral verification bodies or, as is already happening, share it online with global communities that subject it to crowdsourced analysis. But will societal verification generate enthusiasm in the developed and developing worlds alike? What legal protections must be established for participants? And will information gathered through societal verification ultimately prove useful and trustworthy? Three authors explore these emerging questions: from Burkina Faso and representing the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization, Lassina Zerbo (2013); from the United States, research fellow Nima Gerami (2013); and from Malaysia, nuclear engineer Jamal Khaer Ibrahim.

Analysis of Radionuclide Releases from the Fukushima Dai-ichi Nuclear Power Plant Accident Part II

The present part of the publication (Part II) deals with long range dispersion of radionuclides emitted into the atmosphere during the Fukushima Dai-ichi accident that occurred after the March 11, 2011 tsunami. The first part (Part I) is dedicated to the accident features relying on radionuclide detections performed by monitoring stations of the Comprehensive Nuclear Test Ban Treaty Organization network. In this study, the emissions of the three fission products Cs-137, I-131 and Xe-133 are investigated. Regarding Xe-133, the total release is estimated to be of the order of 6 × 1018 Bq emitted during the explosions of units 1, 2 and 3. The total source term estimated gives a fraction of core inventory of about 8 × 1018 Bq at the time of reactors shutdown. This result suggests that at least 80 % of the core inventory has been released into the atmosphere and indicates a broad meltdown of reactor cores. Total atmospheric releases of Cs-137 and I-131 aerosols are estimated to be 1016 and 1017 Bq, respectively. By neglecting gas/particulate conversion phenomena, the total release of I-131 (gas + aerosol) could be estimated to be 4 × 1017 Bq. Atmospheric transport simulations suggest that the main air emissions have occurred during the events of March 14, 2011 (UTC) and that no major release occurred after March 23. The radioactivity emitted into the atmosphere could represent 10 % of the Chernobyl accident releases for I-131 and Cs-137.

Further developments of a robust absolute calibration method utilizing beta/gamma coincidence techniques

Performing accurate and verifiable measurements is often the most challenging goal for any radiation detector and is especially challenging for the radio-xenon detectors deployed by the International Monitoring System (IMS) of the Preparatory Commission of the Comprehensive Test Ban Treaty Organization (CTBTO). Often the accuracy of the measurement is directly tied to how well the detector is calibrated, in both energy and efficiency. Standard methods often rely on using certified sealed sources to determine the absolute efficiency. Similarly, efforts to calibrate the absolute efficiency of radioactive gas cell detectors utilize a number of methodologies which allow adequate calibration but are time consuming and prone to a host of difficulties to determine uncertainties (McIntyre et al, J Radioanal Nucl Chem 282(3):755–759, 2009; Anderson et al, Stat Probab Lett 77(88):769–773, 2007). Utilizing methods developed in the 1960s for absolute measurements of activity with beta–gamma detector systems it has become clear that it is possible to achieve higher precision results that are consistent across a range of isotopes and activities (National Council on Radiation Protection and Measurement, A handbook of radioactivity measurements procedure NCPR report, 1985). Even more compelling is the ease with which this process can be used on routine samples to determine the total activity present in the detector. Additionally, recent advances in the generation of isotopically pure radio-xenon samples of 131mXe, 133Xe, and 135Xe allow these measurement techniques to achieve much better results than have previously been possible when using mixed isotopic radio-xenon sources (Haas et al, J Radioanal Nucl Chem 282(3):677–680, 2009). This paper will discuss the beta/gamma absolute detection efficiency techniques of direct measurement of the efficiencies and the extrapolation method and compare the results using modeled and measured pure sources of 133Xe and 135Xe.

Initial Impact of the Global Seismographic Network Quality Initiative on Metadata Accuracy

The IRIS/USGS Global Seismographic Network (Butler et al. , 2004) is used to investigate earth structure at multiple scales, to capture information about massive earthquakes impossible to obtain at regional scales, and to characterize seismicity in regions of the world where instrument coverage is poor. A key design goal of the GSN, to place high performance instruments at 2,000 km spacing around the planet, has largely been achieved except for portions of the ocean basins. Several agencies, including the USGS National Earthquake Information Center, the NOAA Tsunami Warning Centers, and the United Nations Comprehensive Test Ban Treaty Organization, now utilize GSN seismic data to accomplish their missions. Those who use GSN data rely upon the accuracy of the metadata provided to them through the IRIS’ Data Management System (DMS). The DMS in turn distributes response information supplied by the GSN network operators, the USGS Albuquerque Seismic Laboratory (ASL) and the University of California, San Diego’s Project IDA (IDA). Improved metadata will aid researchers who seek to model earth structure in greater detail as well as those who seek to characterize seismic sources at varying scales. The GSN’s operators continually assess engineering information to ensure that waveform quality is maximized and that published metadata accurately reflect the instrument response of the data acquisition systems (DASs). A detailed description of those operational procedures currently used to accomplish these goals can be found at the IRIS GSN Quality web page (http://www.iris.edu/hq/programs/gsn/quality). One important element of this effort is the practice of colocating a portable, broadband seismometer in proximity to GSN sensors during field-maintenance visits to verify the in situ sensors’ calibration and orientation. The calibration of this portable sensor is measured in the laboratory. Without this additional experimental evidence, the validity of comparing the outputs of permanent and temporary sensors and also …

Small-scale heterogeneities below the Lanzhou CTBTO seismic array, from seismic wave field fluctuations

Seismic wave field fluctuations below Lanzhou Comprehensive Test Ban Treaty Organization seismic array are determined and interpreted to describe the scattering characteristics of the crust beneath the northeastern margin of Qinghai–Tibet plateau in China. The frequency-dependent intensities of the mean and fluctuation wave fields are analyzed for 21 deep (206–632 km depth) teleseismic events. The observed wave field fluctuations in the frequency range 0.5–2.5 Hz can be explained by the scattering of the teleseismic P wave front at random media-type structures. The stable and narrow range of the fluctuation parameters from these teleseismic events indicates evidence for scattered seismic phases which are generated inside the crust. The reasonable structural models contain heterogeneities with 1–3% velocity fluctuations and 2.4–8.2 km correlation lengths in the crust with 53 km thickness.

Fission product ratios as treaty monitoring discriminants

The International Monitoring System (IMS) of the Comprehensive Test Ban Treaty Organization (CTBTO) is currently under construction. The IMS is intended for monitoring of nuclear explosions. The radionuclide part of the IMS monitors the atmosphere for short-lived radioisotopes indicative of a nuclear weapon test, and includes field collection and measurement stations, as well as laboratories to provide reanalysis of the most important samples and a quality control function. The Pacific Northwest National Laboratory in Richland, Washington hosts the United States IMS laboratory, with the designation “RL16.” Since acute reactor containment failures and chronic reactor leakage may also produce similar isotopes, it is tempting to compute ratios of detected isotopes to determine the relevance of an event to the treaty or agreement in question. In this paper we will note several shortcomings of simple isotopic ratios: (1) fractionation of different chemical species, (2) difficulty in comparing isotopes within a single element, and (3) the effect of unknown decay times. While these shortcomings will be shown in the light of an aerosol sample, several of the problems extend to xenon isotopic ratios. Due to the difficulties listed above, considerable human expertise will be required to convert a simple mathematical isotope ratio into a criterion which will reliably categorize an event as ‘reactor’ or ‘weapon’.

A comparison of infrasound signals refracted from stratospheric and thermospheric altitudes

Over the last several years, a large number of ground‐based infrasound arrays have been established for explosion monitoring as part of the International Monitoring System of the Comprehensive Nuclear Test Ban Treaty Organization. Results from these arrays have become valuable in understanding long‐range infrasound propagation in the atmosphere and complement earlier data. Two types of signals are often observed for a given source: those refracted at stratospheric heights and at thermospheric heights. In this contribution we compare several characteristics of these two signal types including observed pressure amplitude, average travel velocity, bearing, and signal duration. For this study we use archival data from atmospheric nuclear explosions, high explosive chemical explosions on the surface, earthquakes with previously detected stratospheric signals, and earthquakes for which stratospheric signals were not detected. We show that the combination of stratospheric and thermospheric signals may provide independent estimates of wind propagation conditions and source characteristics. The observations of both signal types may increase the confidence level of an infrasound signal detection.

An improved UK local magnitude scale from analysis of shear andLg-wave amplitudes

The amplitudes of shear and Lg waves recorded at UK seismograph stations from local earthquakes in the range 0–600 km have been subjected to an analysis of variance, allowing separation of the effects of earthquake size, distance and station corrections for each recording site. The propagation paths sample mainly the central to western part of the UK, with good north–south coverage. The analysis of 385 amplitude readings at 28 stations from 40 earthquakes showed that the effects of both distance and station (site) corrections were statistically significant. Tables of corrections for both distance and station effects have been derived to allow local magnitude ML to be determined more accurately from horizontal and vertical component records. One set of tables allows the estimation of an ML which is consistent with the original Richter definition of ML, with a standard deviation which is smaller than that produced by the theoretical attenuation curve, defined according to attenuation in Southern California, which has customarily been used to calculate ML in the UK. The reduction in standard deviation is mainly due to the incorporation of station terms to correct for station effects, since the theoretical and observed variations of attenuation with distance are similar. This similarity implies that Southern California and the UK show a similar variation of distance-dependent attenuation for Lg waves, which was not expected in view of the differences in geology and tectonics. Another set of tables is provided to calculate an ML which is consistent with the body wave magnitude mb determined by the International Data Centre from station records of the Comprehensive Test-Ban Treaty Organization’s global monitoring network. The decay with distance of the predominantly Lg-wave amplitude values gives a value of 440 ± 50 for Lg Q at a frequency of 3 Hz, in agreement with estimates obtained from spectral displacement amplitudes of Lg waves in the UK.

TESTING OF HIGH-VOLUME SAMPLER INLETS FOR THE SAMPLING OF ATMOSPHERIC RADIONUCLIDES

Sampling of air for radioactive particles is one of the most important techniques used to determine the nuclear debris from a nuclear weapon test in the Earth's atmosphere or those particles vented from underground or underwater tests. Massive-flow air samplers are used to sample air for any indication of radionuclides that are a signature of nuclear tests. The International Monitoring System of the Comprehensive Nuclear Test Ban Treaty Organization includes seismic, hydroacoustic, infrasound, and gaseous xenon isotopes sampling technologies, in addition to radionuclide sampling, to monitor for any violation of the treaty. Lovelace Respiratory Research Institute has developed a large wind tunnel to test the outdoor radionuclide samplers for the International Monitoring System. The inlets for these samplers are tested for their collection efficiencies for different particle sizes at various wind speeds. This paper describes the results from the testing of two radionuclide sampling units used in the International Monitoring System. The possible areas of depositional wall losses are identified and the losses in these areas are determined. Sampling inlet type 1 was tested at 2.2 m s wind speed for 5, 10, and 20-microm aerodynamic diameter particles. The global collection efficiency was about 87.6% for 10-microm particles for sampling inlet type 1. Sampling inlet type 2 was tested for three wind speeds at 0.56, 2.2, and 6.6 m s for 5, 10, and 20-microm aerodynamic diameter particles in two different configurations (sampling head lowered and raised). The global collection efficiencies for these configurations for 10-microm particles at 2.2 m s wind speed were 77.4% and 82.5%, respectively. The sampling flow rate was 600 m h for both sampling inlets.

An Assessment of the Accuracy of GSN Sensor Response Information

The Sumatra-Andaman earthquake of 26 December 2004 provides a special opportunity to validate the accuracy of sensor sensitivities reported for the IRIS Global Seismic Network (GSN). A goal of the GSN is to publish instrument responses to an accuracy of 1% in amplitude and 1° in phase. This earthquake excited long-period free oscillations such that modes with low decay rates could be observed above ambient noise for many weeks after the event. By examining the subset of modes least sensitive to short wavelength structure, one may test the reliability of published station response information. We investigate here the amplitude of the radial mode S , which is predicted to be uniform globally, by using two different techniques. The IRIS Global Seismic Network (Butler et al. , 2004) is now a fully operational scientific facility routinely used to investigate Earth structure and seismicity in many regions of the world where instrument coverage was previously very poor. The principal goal of the GSN, to place high-performance instruments at 2,000 km spacing around the planet, has largely been achieved except for some parts of the oceans. Several agencies, including the USGS National Earthquake Information Center, NOAA Tsunami Warning Centers, and United Nations Comprehensive Test Ban Treaty Organization, now rely routinely on GSN seismic data. Agencies and individual researchers throughout the world depend upon the accuracy of the metadata provided to them through the IRIS Data Management System (http://www.iris.edu/). The IRIS DMS in turn distributes response information supplied by the GSN network operators, the USGS Albuquerque Seismic Lab (ASL) and the University of California at San Diego's Project IDA (IDA). Both network operators conduct tests to measure the instrument response of the equipment they deploy at GSN sites. The Sumatra-Andaman earthquake of 26 December 2004 affords a rare opportunity to assess independently …

Experience with a prototype of the Test Ban Treaty monitoring system for air-borne radioactivity

Monitoring of air-borne radioactivity has been tested on behalf of the Comprehensive Test Ban Treaty Organization. A prototype system was installed at the University of British Columbia, Vancouver, BC in April 1996 and has been operating successfully since then. The air is drawn through a glass-fibre filter for a period of 24 h. A cooling period eliminates products of 222Rn in the uranium series. A germanium detector then counts the γ-rays. Several anthropogenic nuclides such as 123I and 99mTc have been observed from local medical facilities. In addition many natural nuclides have been detected and the most abundant are the products of thoron viz 220Rn, which is in the thorium series. The 239 keV γ-ray from 212Pb has been studied to investigate the reason for significant fluctuations in its intensity. It was found that rain, wind, low temperature and maritime air all decrease the observed activity. A model was created which mimics the variation reasonably well.

Trail in the atmosphere of the 29 December 2000 meteor as recorded in Tahiti: Characteristics and trajectory reconstitution

On 29 December 2000, a meteor entry in the atmosphere produced several bright lights in the sky of Tahiti and intense sonic booms around midnight local time. This event was detected by the Laboratoire de Détection et de Géophysique French Polynesian seismic network and by the IS24 infrasound station in Tahiti operating for the Comprehensive Test Ban Treaty Organization (CTBTO). Both seismic and infrasonic signals indicated that the altitude of the meteor's last explosion was ∼45 km. From the wave azimuth and incidence angle determined through infrasonic data processing, the meteor trajectory has been backtracked over 55 km. Determination of the azimuth and incidence angle of the infrasonic arrivals permitted the determination of a 55 km segment of the meteor trajectory. The velocity of the meteor decreased from 17 to 15 km/s in ∼4 s, while its altitude changed from 55 to 45 km. The diameter and the kinetic energy of the bolide are evaluated using the infrasonic measurements and numerical simulations.