The Experts below are selected from a list of 1464 Experts worldwide ranked by ideXlab platform
M Thoennessen - One of the best experts on this subject based on the ideXlab platform.
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discovery of palladium antimony tellurium iodine and Xenon Isotopes
Atomic Data and Nuclear Data Tables, 2013Co-Authors: J Kathawa, M ThoennessenAbstract:Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty Xenon Isotopes have been observed and the discovery of these Isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.
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Discovery of palladium, antimony, tellurium, iodine, and Xenon Isotopes
Atomic Data and Nuclear Data Tables, 2013Co-Authors: J Kathawa, C. Fry, M ThoennessenAbstract:Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty Xenon Isotopes have been observed and the discovery of these Isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.
James C Hayes - One of the best experts on this subject based on the ideXlab platform.
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improved performance comparisons of radioXenon systems for low level releases in nuclear explosion monitoring
Journal of Environmental Radioactivity, 2017Co-Authors: T W Bowyer, Derek A Haas, James C Hayes, Justin D Lowrey, Paul W Eslinger, Ian M Cameron, Harry S MileyAbstract:Abstract The Comprehensive Nuclear-Test-Ban Treaty bans all nuclear tests and mandates development of verification measures to detect treaty violations. One verification measure is detection of radioactive Xenon Isotopes produced in the fission of actinides. The International Monitoring System (IMS) currently deploys automated radioXenon systems that can detect four radioXenon Isotopes. RadioXenon systems with lower detection limits are currently in development. Historically, the sensitivity of radioXenon systems was measured by the minimum detectable concentration for each isotope. In this paper we analyze the response of radioXenon systems using rigorous metrics in conjunction with hypothetical representative releases indicative of an underground nuclear explosion instead of using only minimum detectable concentrations. Our analyses incorporate the impact of potential spectral interferences on detection limits and the importance of measuring isotopic ratios of the relevant radioXenon Isotopes in order to improve discrimination from background sources particularly for low-level releases. To provide a sufficient data set for analysis, hypothetical representative releases are simulated every day from the same location for an entire year. The performance of three types of samplers are evaluated assuming they are located at 15 IMS radionuclide stations in the region of the release point. The performance of two IMS-deployed samplers and a next-generation system is compared with proposed metrics for detection and discrimination using representative releases from the nuclear test site used by the Democratic People's Republic of Korea.
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estimation of 2 4 0pu mass in a waste tank using ultra sensitive detection of radioactive Xenon Isotopes from spontaneous fission
2014Co-Authors: Ted W Bowyer, Derek A Haas, James C Hayes, Christopher J Gesh, Lenna A Mahoney, Joseph E Meacham, Donaldo P Mendoza, Khris B Olsen, Amanda M Prinke, Bruce D ReidAbstract:We report on a technique to detect and quantify the amount of 240Pu in a large tank used to store nuclear waste from plutonium production at the Hanford nuclear site. While the contents of this waste tank are known from previous grab sample measurements, our technique could allow for determination of the amount of 240Pu in the tank without costly sample retrieval and analysis of this highly radioactive material. This technique makes an assumption, which was confirmed, that 240Pu dominates the spontaneous fissions occurring in the tank.
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abatement of Xenon and iodine emissions from medical isotope production facilities
Journal of Environmental Radioactivity, 2014Co-Authors: Charles G Doll, T W Bowyer, James C Hayes, Judah I Friese, Christina M Sorensen, Emmy Hoffmann, Rosara F KephartAbstract:The capability of the International Monitoring System (IMS) to detect Xenon from underground nuclear explosions is dependent on the radioactive Xenon background. Adding to the background, medical isotope production (MIP) by fission releases several important Xenon Isotopes including Xenon-133 and iodine-133 that decays to Xenon-133. The amount of Xenon released from these facilities may be equivalent to or exceed that released from an underground nuclear explosion. Thus the release of gaseous fission products within days of irradiation makes it difficult to distinguish MIP emissions from a nuclear explosion. In addition, recent shortages in molybdenum-99 have created interest and investment opportunities to design and build new MIP facilities in the United States and throughout the world. Due to the potential increase in the number of MIP facilities, a discussion of abatement technologies provides insight into how the problem of emission control from MIP facilities can be tackled. A review of practices is provided to delineate methods useful for abatement of medical Isotopes.
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potential impact of releases from a new molybdenum 99 production facility on regional measurements of airborne Xenon Isotopes
Journal of Environmental Radioactivity, 2014Co-Authors: Ted W Bowyer, James C Hayes, Paul W Eslinger, Ian M Cameron, Judah I Friese, Lori A Metz, H S MileyAbstract:Abstract The monitoring of the radioactive Xenon Isotopes 131m Xe, 133 Xe, 133m Xe, and 135 Xe is important for the detection of nuclear explosions. While backgrounds of the Xenon Isotopes are short-lived, they are constantly replenished from activities dominated by the fission-based production of 99 Mo used for medical procedures. At present, one of the most critical locations on earth for the monitoring of nuclear explosions is the Korean peninsula where the Democratic People's Republic of Korea (DPRK) has announced that it conducted three nuclear tests between 2006 and 2013. This paper explores the backgrounds that would be caused by the medium to large scale production of 99 Mo in the region of the Korean peninsula.
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detection and analysis of Xenon Isotopes for the comprehensive nuclear test ban treaty international monitoring system
Journal of Environmental Radioactivity, 2002Co-Authors: Ted W Bowyer, M. Auer, Clemens Schlosser, K H Abel, Tom R Heimbigner, J Mcintyre, Mark E Panisko, Paul L Reeder, James C Hayes, H SatoriusAbstract:The use of the Xenon Isotopes for detection of nuclear explosions is of great interest for monitoring compliance with the comprehensive nuclear-test-ban treaty (CTBT). Recently, the automated radioXenon sampler-analyzer (ARSA) was tested at the Institute for Atmospheric Radioactivity (IAR) in Freiburg, Germany to ascertain its use for the CTBT by comparing its results to laboratory-based analyses, determining its detection sensitivity and analyzing its results in light of historical Xenon isotope levels and known reactor operations in the area. Xe-133 was detected nearly every day throughout the test at activity concentrations ranging between approximately 0.1 mBq/m3 to as high as 120 mBq/m3. Xe-133m and 135Xe were also detected occasionally during the test at concentrations of less than 1 to a few mBq/m3.
J Kathawa - One of the best experts on this subject based on the ideXlab platform.
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discovery of palladium antimony tellurium iodine and Xenon Isotopes
Atomic Data and Nuclear Data Tables, 2013Co-Authors: J Kathawa, M ThoennessenAbstract:Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty Xenon Isotopes have been observed and the discovery of these Isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.
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Discovery of palladium, antimony, tellurium, iodine, and Xenon Isotopes
Atomic Data and Nuclear Data Tables, 2013Co-Authors: J Kathawa, C. Fry, M ThoennessenAbstract:Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty Xenon Isotopes have been observed and the discovery of these Isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.
Martin Kalinowski - One of the best experts on this subject based on the ideXlab platform.
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computation and analysis of the global distribution of the radioXenon isotope 133xe based on emissions from nuclear power plants and radioisotope production facilities and its relevance for the verification of the nuclear test ban treaty
Pure and Applied Geophysics, 2010Co-Authors: Andreas Becker, Gerhard Wotawa, Paul R J Saey, Martin Kalinowski, Matthias P Tuma, Matthias ZahringerAbstract:Monitoring of radioactive noble gases, in particular Xenon Isotopes, is a crucial element of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The capability of the noble gas network, which is currently under construction, to detect signals from a nuclear explosion critically depends on the background created by other sources. Therefore, the global distribution of these Isotopes based on emissions and transport patterns needs to be understood. A significant Xenon background exists in the reactor regions of North America, Europe and Asia. An emission inventory of the four relevant Xenon Isotopes has recently been created, which specifies source terms for each power plant. As the major emitters of Xenon Isotopes worldwide, a few medical radioisotope production facilities have been recently identified, in particular the facilities in Chalk River (Canada), Fleurus (Belgium), Pelindaba (South Africa) and Petten (Netherlands). Emissions from these sites are expected to exceed those of the other sources by orders of magnitude. In this study, emphasis is put on 133Xe, which is the most prevalent Xenon isotope. First, based on the emissions known, the resulting 133Xe concentration levels at all noble gas stations of the final CTBT verification network were calculated and found to be consistent with observations. Second, it turned out that emissions from the radioisotope facilities can explain a number of observed peaks, meaning that atmospheric transport modelling is an important tool for the categorization of measurements. Third, it became evident that Nuclear Power Plant emissions are more difficult to treat in the models, since their temporal variation is high and not generally reported. Fourth, there are indications that the assumed annual emissions may be underestimated by factors of two to ten, while the general emission patterns seem to be well understood. Finally, it became evident that 133Xe sources mainly influence the sensitivity of the monitoring system in the mid-latitudes, where the network coverage is particularly good.
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computation and analysis of the global distribution of the radioXenon isotope 133 xe based on emissions from nuclear power plants and radioisotope production facilities and its relevance for the verification of the nuclear test ban treaty
Pure and Applied Geophysics, 2010Co-Authors: Andreas Becker, Gerhard Wotawa, Paul R J Saey, Martin Kalinowski, Matthias P Tuma, Matthias ZahringerAbstract:Monitoring of radioactive noble gases, in particular Xenon Isotopes, is a crucial element of the verification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The capability of the noble gas network, which is currently under construction, to detect signals from a nuclear explosion critically depends on the background created by other sources. Therefore, the global distribution of these Isotopes based on emissions and transport patterns needs to be understood. A significant Xenon background exists in the reactor regions of North America, Europe and Asia. An emission inventory of the four relevant Xenon Isotopes has recently been created, which specifies source terms for each power plant. As the major emitters of Xenon Isotopes worldwide, a few medical radioisotope production facilities have been recently identified, in particular the facilities in Chalk River (Canada), Fleurus (Belgium), Pelindaba (South Africa) and Petten (Netherlands). Emissions from these sites are expected to exceed those of the other sources by orders of magnitude. In this study, emphasis is put on 133Xe, which is the most prevalent Xenon isotope. First, based on the emissions known, the resulting 133Xe concentration levels at all noble gas stations of the final CTBT verification network were calculated and found to be consistent with observations. Second, it turned out that emissions from the radioisotope facilities can explain a number of observed peaks, meaning that atmospheric transport modelling is an important tool for the categorization of measurements. Third, it became evident that Nuclear Power Plant emissions are more difficult to treat in the models, since their temporal variation is high and not generally reported. Fourth, there are indications that the assumed annual emissions may be underestimated by factors of two to ten, while the general emission patterns seem to be well understood. Finally, it became evident that 133Xe sources mainly influence the sensitivity of the monitoring system in the mid-latitudes, where the network coverage is particularly good.
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global radioXenon emission inventory based on nuclear power reactor reports
Journal of Environmental Radioactivity, 2009Co-Authors: Martin Kalinowski, Matthias P TumaAbstract:Abstract Atmospheric radioactivity is monitored for the verification of the Comprehensive Nuclear-Test-Ban Treaty, with Xenon Isotopes 131m Xe, 133 Xe, 133m Xe and 135 Xe serving as important indicators of nuclear explosions. The treaty-relevant interpretation of atmospheric concentrations of radioXenon is enhanced by quantifying radioXenon emissions released from civilian facilities. This paper presents the first global radioXenon emission inventory for nuclear power plants, based on North American and European emission reports for the years 1995–2005. Estimations were made for all power plant sites for which emission data were unavailable. According to this inventory, a total of 1.3 PBq of radioXenon Isotopes are released by nuclear power plants as continuous or pulsed emissions in a generic year.
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isotopic signature of atmospheric Xenon released from light water reactors
Journal of Environmental Radioactivity, 2006Co-Authors: Martin Kalinowski, Christoph PistnerAbstract:Abstract A global monitoring system for atmospheric Xenon radioactivity is being established as part of the International Monitoring System to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The isotopic activity ratios of 135 Xe, 133m Xe, 133 Xe and 131m Xe are of interest for distinguishing nuclear explosion sources from civilian releases. Simulations of light water reactor (LWR) fuel burn-up through three operational reactor power cycles are conducted to explore the possible Xenon isotopic signature of nuclear reactor releases under different operational conditions. It is studied how ratio changes are related to various parameters including the neutron flux, uranium enrichment and fuel burn-up. Further, the impact of diffusion and mixing on the isotopic activity ratio variability are explored. The simulations are validated with reported reactor emissions. In addition, activity ratios are calculated for Xenon Isotopes released from nuclear explosions and these are compared to the reactor ratios in order to determine whether the discrimination of explosion releases from reactor effluents is possible based on isotopic activity ratios.
Grenville Turner - One of the best experts on this subject based on the ideXlab platform.
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Constraints on Nucleosynthesis from Xenon Isotopes in Presolar Material
The Astrophysical Journal, 2007Co-Authors: Jamie D Gilmour, Grenville TurnerAbstract:By applying theoretical constraints to three-dimensional fits of Xenon isotope data from presolar grains, we show that they strongly suggest a nucleosynthesis process that produces "r-process" Isotopes without producing s-process Isotopes (128Xe, 130Xe) and without producing the conventional r-process isotope 136Xe. It is one of three distinct nucleosynthetic sources that are necessary and sufficient to explain the gross variation in Xenon isotopic data across all presolar material. The other source contributing r-process Isotopes is responsible for the heavy isotope signature identified in nanodiamonds, which is also present in presolar SiC, and is associated with light isotope enrichment. The relative enrichments of heavy and light Isotopes in this component in nanodiamonds and SiC grains are different, implying that the parent nucleosynthetic processes are not inextricably linked. Because minor variations in the isotopic compositions of Xenon trapped in nanodiamonds show that two distinct sites contributed nanodiamonds to the early solar system within the average grain lifetime, it is suggested that Type IIa supernovae (SNe IIa) are not the source of the nanodiamonds. The s-process signature derived is consistent with that derived from mixing lines between grain subpopulations for Isotopes on the s-process path. This implies that a pure end-member is present in the grains (although not approached in analyses). Our approach is more general and provides a less restrictive set of numerical constraints to be satisfied by proposed theoretical treatments of nucleosynthesis.
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Xenon Isotopes in size separated nanodiamonds from Efremovka 129Xe*, Xe-P3, and Xe-P6.
Geochimica et Cosmochimica Acta, 2005Co-Authors: Jamie D Gilmour, A. B. Verchovsky, A. V. Fisenko, Greg Holland, Grenville TurnerAbstract:Xenon isotopic data were acquired by high resolution step pyrolysis and combined step pyrolysis/combustion of aliquots of size separated nanodiamonds. 129Xe excess (129Xe*) from in situ decay of 129I is preferentially associated with the larger grain size separates. This observation rules out trapping by recoil from surrounding material. The releases of Xe-P3 and 129Xe occur in the same low temperature pyrolysis steps and exhibit similar distributions among the size separates. These observations imply a common site for the components and, in consequence, suggest a common incorporation event. Whether one component or two, our observations require that 129Xe* and Xe-P3 were incorporated into a subpopulation of nanodiamonds before nanodiamonds were mixed and incorporated into parent bodies. Their susceptibilities to loss during heating in the laboratory are similar, but the ratio of 129Xe* to Xe-P3 varies among nanodiamond separates from different meteorites (literature data). We conclude that the 129Xe* we observe today was present as 129I during parent body processing. Furthermore, the range of 129Xe*/132XeP3 ratios across all the separates requires that even nanodiamonds from CI chondrites were at least 5–10× more rich in Xe-P3 during 129I decay than they are today. We present a simple model involving one degassing event per parent body between incorporation of nanodiamonds and final decay of 129I. The observed variations among parent bodies require degassing events separated by several 129I half lives (∼50Ma), consistent with low-temperature processing on parent bodies but longer than expected for nebular processing. In this model, nanodiamonds from ALHA77307 degassed at an unusually early stage, suggesting they alone may retain the signature of processing in the nebula in their P3 and 129Xe* abundances. The isotopic signature associated with Xe-P6 is also found only in the larger size separates. Concentration of Xe-HL increases with increasing grain size, but its relative abundance with respect to Xe-P3 and P6 is higher in smaller grain-size fractions. We argue that Xe-P6 is best seen as a variant of Xe-HL, and that they are both mixtures of a “normal” component akin to solar Xenon and a slightly variable exotic component. We show that both current models of Xe-H formation can account for the observed variability, and propose a scenario according to which Xe-HL and P6 were implanted into separate diamond populations before incorporation of Xe-P3 and 129I.
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Xenon Isotopes IN IRRADIATED ALH84001 : EVIDENCE FOR SHOCK-INDUCED TRAPPING OF ANCIENT MARTIAN ATMOSPHERE
Geochimica et Cosmochimica Acta, 1998Co-Authors: Jamie D Gilmour, James A. Whitby, Grenville TurnerAbstract:Abstract Laser spot fusion and high resolution stepped heating analyses of neutron irradiated and unirradiated samples of ALH84001 have allowed us to identify the site of the major trapped Xe component as orthopyroxene. The apparent depletion of Ar and Kr relative to Xe and the high concentration of trapped Xe suggest the trapping mechanism was adsorption followed by shock incorporation into the major mineral phase. Carbonate, apatite, and feldspathic glass have also been studied and eliminated as major contributors to the trapped Xenon budget, although a clear spallation signature was found in analysis of a single apatite grain. Carbonate contains iodine at a concentration of ∼500 ppb, and evidence of an associated minor release of Martian atmosphere suggests that this is not terrestrial contamination. There is no evidence of in situ decay of 129 I or 244 Pu in the meteorite. However, the 129 Xe/ 132 Xe ratio of the trapped component (1.95 ± 0.18) is significantly lower than that of the present Martian atmosphere, and differences in the associated 136 Xe/ 132 Xe ratio from that expected from Martian mantle-Martian atmosphere mixing suggest trapping took place before the atmosphere had evolved to its present state. We believe that trapping was associated with the shock that produced the crush zones and so was no later than resetting of the Ar-Ar system 4 Ga ago.
