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Haber DA, Burnley PC, Adcock CT, Malchow RL, Marsac KE, Hausrath EM. Modeling background radiation in Southern Nevada. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 171:41-64. [PMID: 28182978 DOI: 10.1016/j.jenvrad.2017.01.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation environment is unknown. Two study areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.
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Affiliation(s)
- Daniel A Haber
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV, 89154, United States; National Security Technologies, Aerial Measuring Systems, Remote Sensing Laboratory, PO Box 98521, Las Vegas, NV, 89193, United States.
| | - Pamela C Burnley
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV, 89154, United States.
| | - Christopher T Adcock
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV, 89154, United States.
| | - Russell L Malchow
- National Security Technologies, Aerial Measuring Systems, Remote Sensing Laboratory, PO Box 98521, Las Vegas, NV, 89193, United States.
| | - Kara E Marsac
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV, 89154, United States; Colorado School of Mines, Department of Civil and Environmental Engineering, 1500 Illinois St., Golden, CO 80401, United States.
| | - Elisabeth M Hausrath
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV, 89154, United States.
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Haber DA, Malchow RL, Burnley PC. Monte Carlo simulations of the gamma-ray exposure rates of common rocks. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 167:20-25. [PMID: 27890299 DOI: 10.1016/j.jenvrad.2016.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/19/2016] [Accepted: 11/11/2016] [Indexed: 06/06/2023]
Abstract
Monte Carlo simulations have been performed to model the gamma ray emission and attenuation properties of common rocks. In geologic materials, 40K, 238U, and 232Th are responsible for most gamma ray production. If the concentration of these radioelements and attenuation factors such as degree of water saturation are known, an estimate of the gamma-ray exposure rate can be made. The results show that there are no significant differences in gamma-ray screening between major rock types. If the total number of radionuclide atoms are held constant then the major controlling factor is density of the rock. Finally, the thickness of regolith or soil overlying rock can be estimated by modeling the exposure rate if the radionuclide contents of both materials are known.
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Affiliation(s)
- Daniel A Haber
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV 89154, USA; National Security Technologies, Aerial Measuring Systems, Remote Sensing Laboratory, PO Box 98521, Las Vegas, NV 89193, USA.
| | - Russell L Malchow
- National Security Technologies, Aerial Measuring Systems, Remote Sensing Laboratory, PO Box 98521, Las Vegas, NV 89193, USA.
| | - Pamela C Burnley
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV 89154, USA.
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Marsac KE, Burnley PC, Adcock CT, Haber DA, Malchow RL, Hausrath EM. Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 165:68-85. [PMID: 27640123 DOI: 10.1016/j.jenvrad.2016.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 07/06/2016] [Accepted: 07/09/2016] [Indexed: 06/06/2023]
Abstract
This study compares high resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (National Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.
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Affiliation(s)
- Kara E Marsac
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV 89154, United States.
| | - Pamela C Burnley
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV 89154, United States.
| | - Christopher T Adcock
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV 89154, United States.
| | - Daniel A Haber
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV 89154, United States.
| | - Russell L Malchow
- National Security Technologies, Aerial Measuring Systems, Remote Sensing Laboratory, PO Box 98521, Las Vegas, NV 89193, United States.
| | - Elisabeth M Hausrath
- University of Nevada Las Vegas, Geoscience Department, 4505 S Maryland Parkway, Las Vegas, NV 89154, United States.
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Cresswell AJ, Sanderson DCW, Harrold M, Kirley B, Mitchell C, Weir A. Demonstration of lightweight gamma spectrometry systems in urban environments. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 124:22-28. [PMID: 23639691 DOI: 10.1016/j.jenvrad.2013.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 03/14/2013] [Accepted: 03/16/2013] [Indexed: 06/02/2023]
Abstract
Urban areas present highly complex radiation environments; with small scale features resulting from different construction materials, topographic effects and potential anthropogenic inputs from past industrial activity or other sources. Mapping of the radiation fields in urban areas allows a detailed assessment of exposure pathways for the people who live and work there, as well as locating discrete sources of activity that may warrant removal to mitigate dose to the general public. These areas also present access difficulties for radiometric mapping using vehicles or aircraft. A lightweight portable gamma spectrometry system has been used to survey sites in the vicinity of Glasgow to demonstrate the possibilities of radiometric mapping of urban areas, and to investigate the complex radiometric features such areas present. Variations in natural activity due to construction materials have been described, the presence of (137)Cs used to identify relatively undisturbed ground, and a previously unknown NORM feature identified. The effect of topographic enclosure on measurements of activity concentration has been quantified. The portable system is compared with the outputs that might be expected from larger vehicular or airborne systems. For large areas airborne surveys are the most cost effective approach, but provide limited spatial resolution, vehicular surveys can provide sparse exploratory data rapidly or detailed mapping of open areas where off-road access is possible. Backpack systems are ideally suited to detailed surveys of small areas, especially where vehicular access is difficult.
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Affiliation(s)
- A J Cresswell
- Scottish Universities Environmental Research Centre, Scottish Enterprise Technology Park, East Kilbride G75 0QF, UK.
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MINATO S. Wide Range Wave-Number Spectra of Place-to-Place Variations in Terrestrial Gamma-Ray Exposure Rate. J NUCL SCI TECHNOL 1986. [DOI: 10.1080/18811248.1986.9735019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Løvborg L, Bøtter-Jensen L, Kirkegaard P, Christiansen E. Monitoring of natural soil radioactivity with portable gamma-ray spectrometers. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/0029-554x(79)90021-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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