Receiving information from airborne gamma-ray spectra is based on the ability to estimate the pho... more Receiving information from airborne gamma-ray spectra is based on the ability to estimate the photopeak areas in the regular spectra of natural and other sources. In the airborne gamma-ray spectrometry, extracting the photopeaks of radionuclides from regular onesecond spectra is a complicated problem. In the region of higher energies, e.g., above 1.6 MeV, the difficulties are associated with low count rates, while in the region of lower energies, difficulties are due to a significant background level and its statistical noise. In this article a new procedure is proposed to process the measured spectra up to extracting evident photopeaks. The procedure consists of decreasing noises in energy channels along the flight lines, transforming spectra to equal resolution spectra, removing baselines from each spectrum, sharpening details, and transforming spectra back to original channel scale. The resulting spectra are better suited for examining and using the photopeaks. No assumptions regarding the number, positions and magnitudes of photopeaks are needed. Non-negativity of photopeak areas is ensured by the procedure. The proposed technique is likely to contribute to studies of environmental issues, soil characterization and other near surface geophysical methods.
Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the... more Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the geological situation is uniform and the conditions of measurements are quite constant within footprint area with possible exception of flight height variations in a small range. Any violation of these conditions leads to certain problems. In reality, violations such as large changes of flight height and/or rugged terrain are not that rare as well as sharp changes in composition of surface rocks. This article proposes an approach where the solutions of inverse problems are used for data processing. The approach is quite natural in the processing of field data measured along the flight lines: it explicitly takes into account one-dimensional models of survey and flight parametersfrom topography to sources distribution on the surface. Also, it clearly demonstrates that the inverse problem of Airborne Gamma-Ray Spectrometry data does not have a unique solution. This feature can be used in accordance with the geological problem in hands because various formulations of inverse problems can lead to various geological solutions. The use of the approach is illustrated by several examples given for both flight lines and survey areas.
In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abu... more In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abundances of natural potassium, uranium, and thorium in near-surface rocks. The estimation of uranium is a difficult and important problem due to the presence of radon in the air that has no geological value. This problem arises because the main emitters of the U-238 radioactive family are the same both in air and in the ground, and they cannot be distinguished by energy. Without corrections for radon in the air, data on uranium geological emitters can be distorted beyond recognition (overestimated many times). Several methods for radon correction are known. They are based on various approaches to compare the different parts of spectra. The presence of radon changes the spectra in two ways - in the areas of photopeaks and Compton scattering. Both these features are used here to construct two new radon corrections. The first correction uses the standard geophysical model of two half-spaces near every data point. The second correction uses empirical local features of the spectra near the photopeaks.
Journal of environmental radioactivity, Jan 29, 2017
Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the... more Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the measurement conditions are almost constant within several footprint area sizes, with the possible exception of flight height variations in a small range. In practice, deviations, such as large or abrupt changes of flight height and/or rugged terrain are not so rare and lead to certain problems. This article proposes a different approach where the solutions of inverse problems are used for data processing. The approach is quite natural in the processing of field data measured along the flight lines: it explicitly takes into account 1.5D survey models and flight parameters - from topography to sources distribution on the surface. Also, it clearly demonstrates that the inverse problem of the Airborne Gamma-Ray Spectrometry does not have a unique solution. This feature can be used in accordance with the underlying geological problem since various formulations of inverse problems can lead to...
In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abu... more In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abundances of natural potassium, uranium, and thorium in near-surface rocks. The estimation of uranium is a difficult and important problem due to the presence of radon in the air that has no geological value. This problem arises because the main emitters of the U-238 radioactive family are the same both in air and in the ground, and they cannot be distinguished by energy. Without corrections for radon in the air, data on uranium geological emitters can be distorted beyond recognition (overestimated many times). Several methods for radon correction are known. They are based on various approaches to compare the different parts of spectra. The presence of radon changes the spectra in two ways - in the areas of photopeaks and Compton scattering. Both these features are used here to construct two new radon corrections. The first correction uses the standard geophysical model of two half-spaces near every data point. The second correction uses empirical local features of the spectra near the photopeaks.
Receiving information from airborne gamma-ray spectra is based on the ability to estimate the pho... more Receiving information from airborne gamma-ray spectra is based on the ability to estimate the photopeak areas in the regular spectra of natural and other sources. In the airborne gamma-ray spectrometry, extracting the photopeaks of radionuclides from regular onesecond spectra is a complicated problem. In the region of higher energies, e.g., above 1.6 MeV, the difficulties are associated with low count rates, while in the region of lower energies, difficulties are due to a significant background level and its statistical noise. In this article a new procedure is proposed to process the measured spectra up to extracting evident photopeaks. The procedure consists of decreasing noises in energy channels along the flight lines, transforming spectra to equal resolution spectra, removing baselines from each spectrum, sharpening details, and transforming spectra back to original channel scale. The resulting spectra are better suited for examining and using the photopeaks. No assumptions regarding the number, positions and magnitudes of photopeaks are needed. Non-negativity of photopeak areas is ensured by the procedure. The proposed technique is likely to contribute to studies of environmental issues, soil characterization and other near surface geophysical methods.
Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the... more Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the geological situation is uniform and the conditions of measurements are quite constant within footprint area with possible exception of flight height variations in a small range. Any violation of these conditions leads to certain problems. In reality, violations such as large changes of flight height and/or rugged terrain are not that rare as well as sharp changes in composition of surface rocks. This article proposes an approach where the solutions of inverse problems are used for data processing. The approach is quite natural in the processing of field data measured along the flight lines: it explicitly takes into account one-dimensional models of survey and flight parametersfrom topography to sources distribution on the surface. Also, it clearly demonstrates that the inverse problem of Airborne Gamma-Ray Spectrometry data does not have a unique solution. This feature can be used in accordance with the geological problem in hands because various formulations of inverse problems can lead to various geological solutions. The use of the approach is illustrated by several examples given for both flight lines and survey areas.
In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abu... more In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abundances of natural potassium, uranium, and thorium in near-surface rocks. The estimation of uranium is a difficult and important problem due to the presence of radon in the air that has no geological value. This problem arises because the main emitters of the U-238 radioactive family are the same both in air and in the ground, and they cannot be distinguished by energy. Without corrections for radon in the air, data on uranium geological emitters can be distorted beyond recognition (overestimated many times). Several methods for radon correction are known. They are based on various approaches to compare the different parts of spectra. The presence of radon changes the spectra in two ways - in the areas of photopeaks and Compton scattering. Both these features are used here to construct two new radon corrections. The first correction uses the standard geophysical model of two half-spaces near every data point. The second correction uses empirical local features of the spectra near the photopeaks.
Journal of environmental radioactivity, Jan 29, 2017
Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the... more Standard processing of Airborne Gamma-Ray Spectrometry data generally gives good results when the measurement conditions are almost constant within several footprint area sizes, with the possible exception of flight height variations in a small range. In practice, deviations, such as large or abrupt changes of flight height and/or rugged terrain are not so rare and lead to certain problems. This article proposes a different approach where the solutions of inverse problems are used for data processing. The approach is quite natural in the processing of field data measured along the flight lines: it explicitly takes into account 1.5D survey models and flight parameters - from topography to sources distribution on the surface. Also, it clearly demonstrates that the inverse problem of the Airborne Gamma-Ray Spectrometry does not have a unique solution. This feature can be used in accordance with the underlying geological problem since various formulations of inverse problems can lead to...
In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abu... more In Airborne Gamma-Ray Spectrometry, the main geological goal of data processing is to get the abundances of natural potassium, uranium, and thorium in near-surface rocks. The estimation of uranium is a difficult and important problem due to the presence of radon in the air that has no geological value. This problem arises because the main emitters of the U-238 radioactive family are the same both in air and in the ground, and they cannot be distinguished by energy. Without corrections for radon in the air, data on uranium geological emitters can be distorted beyond recognition (overestimated many times). Several methods for radon correction are known. They are based on various approaches to compare the different parts of spectra. The presence of radon changes the spectra in two ways - in the areas of photopeaks and Compton scattering. Both these features are used here to construct two new radon corrections. The first correction uses the standard geophysical model of two half-spaces near every data point. The second correction uses empirical local features of the spectra near the photopeaks.
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