scholarly journals Integration of Ground- Penetrating Radar and Gamma-Ray Detectors for Nonintrusive Characterisation of Buried Radioactive Objects

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2743
Author(s):  
Ikechukwu K. Ukaegbu ◽  
Kelum A. A. Gamage ◽  
Michael D. Aspinall
Keyword(s):  
Numerical Simulations ◽  
Relative Error ◽  
Ground Penetrating Radar ◽  
Gamma Ray ◽  
Radioactive Wastes ◽  
Soil Density ◽  
Gamma Ray Detectors ◽  
Density Relationship ◽  
Ground Penetrating ◽  
Gamma Ray Detector

The characterisation of buried radioactive wastes is challenging because they are not readily accessible. Therefore, this study reports on the development of a method for integrating ground-penetrating radar (GPR) and gamma-ray detector measurements for nonintrusive characterisation of buried radioactive objects. The method makes use of the density relationship between soil permittivity models and the flux measured by gamma ray detectors to estimate the soil density, depth and radius of a disk-shaped buried radioactive object simultaneously. The method was validated using numerical simulations with experimentally-validated gamma-ray detector and GPR antenna models. The results showed that the method can simultaneously retrieve the soil density, depth and radius of disk-shaped radioactive objects buried in soil of varying conditions with a relative error of less than 10%. This result will enable the development of an integrated GPR and gamma ray detector tool for rapid characterisation of buried radioactive objects encountered during monitoring and decontamination of nuclear sites and facilities.

scholarly journals Nonintrusive Depth Estimation of Buried Radioactive Wastes Using Ground Penetrating Radar and a Gamma Ray Detector

2019 ◽  
Vol 11 (2) ◽  
pp. 141 ◽  
Author(s):  
Ikechukwu Ukaegbu ◽  
Kelum Gamage ◽  
Michael Aspinall
Keyword(s):  
Bulk Density ◽  
Ground Penetrating Radar ◽  
Gamma Ray ◽  
Depth Estimation ◽  
Average Error ◽  
Density Estimates ◽  
Material Density ◽  
Linear Correction ◽  
Ground Penetrating ◽  
Gamma Ray Detector

This study reports on the combination of data from a ground penetrating radar (GPR) and a gamma ray detector for nonintrusive depth estimation of buried radioactive sources. The use of the GPR was to enable the estimation of the material density required for the calculation of the depth of the source from the radiation data. Four different models for bulk density estimation were analysed using three materials, namely: sand, gravel and soil. The results showed that the GPR was able to estimate the bulk density of the three materials with an average error of 4.5%. The density estimates were then used together with gamma ray measurements to successfully estimate the depth of a 658 kBq ceasium-137 radioactive source buried in each of the three materials investigated. However, a linear correction factor needs to be applied to the depth estimates due to the deviation of the estimated depth from the measured depth as the depth increases. This new application of GPR will further extend the possible fields of application of this ubiquitous geophysical tool.

scholarly journals Identifying a soil hydraulic parameterisation from on-ground GPR time lapse measurements of a pumping experiment

2012 ◽  
Vol 9 (8) ◽  
pp. 9095-9117 ◽  
Author(s):  
A. Dagenbach ◽  
J. Buchner ◽  
P. Klenk ◽  
K. Roth
Keyword(s):  
Quantitative Analysis ◽  
Numerical Simulations ◽  
Water Content ◽  
Water Table ◽  
Ground Penetrating Radar ◽  
Time Lapse ◽  
Radar Signal ◽  
Capillary Fringe ◽  
Ground Penetrating ◽  
Over Time

Abstract. We show the potential of on-ground Ground-Penetrating Radar (GPR) to identify the hydraulic parameterisation with a semi-quantitative analysis based on numerical simulations of the radar signal. A pumping experiment has been conducted at the ASSESS-GPR site to establish a fluctuating water table, while an on-ground GPR antenna recorded traces over time at a fixed location. These measurements allow to identify and track the capillary fringe in the soil. The typical dynamics of soil water content with a transient water table can be deduced from the recorded radargrams. The characteristic reflections from the capillary fringes in model soils that are described by commonly used hydraulic parameterisations are investigated by numerical simulations. The parameterisations used are: (i) full van Genuchten, (ii) simplified van Genuchten with m = 1 − 1/n and (iii) Brooks-Corey. All three yield characteristically different reflections, which allows the identification of an appropriate parameterisation by comparing to the measured signals. We show that these are not consistent with the commonly used simplified van Genuchten parameterisation with m = 1 − 1/n.

scholarly journals Simulation Study of a Shield-free Directional Gamma-ray Detector Using Small-angle Compton Scattering

2020 ◽  
Author(s):  
Yoshiharu Kitayama ◽  
Yuta Terasaka ◽  
Yuki Sato ◽  
Tatsuo Torii
Keyword(s):  
Compton Scattering ◽  
Small Angle ◽  
Gamma Ray ◽  
Small Angle Scattering ◽  
Scattered Electron ◽  
Technology Study ◽  
Gamma Ray Detectors ◽  
Angle Scattering ◽  
Gamma Ray Imaging ◽  
Gamma Ray Detector

Abstract Gamma-ray imaging is a technique for visualize the spatial distribution of radioactive materials. Gamma-ray imaging has recently been applied to research on environmental restoration and decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS). In the present paper, we present an elemental technology study of the Gamma-ray Imager using Small-Angle Scattering (GISAS), which is intended for application at the FDNPS decommissioning site. GISAS consists of a set of directional gamma-ray detectors that do not require a shield. In this study, we investigated the feasibility of a shield-free directional gamma-ray detector by simulation. The simulation result suggests that by measuring scattered-electron energies of several keV using a scatterer detector, gamma rays with ultra-small-angle scattering could be selected. Using Compton scattering kinematics, a shield-free detector with a directivity of about 10 degree may be feasible. By arranging the directional gamma-ray detectors in an array, we expect to be able to realize the GISAS, which is small, light, and capable of quantitative measurement.

Towards the multi-scale characterization of braided fluvial geobodies from outcrop, core, ground-penetrating radar and well log data

2018 ◽  
Vol 488 (1) ◽  
pp. 73-95 ◽  
Author(s):  
Luis Miguel Yeste ◽  
Saturnina Henares ◽  
Neil McDougall ◽  
Fernando García-García ◽  
César Viseras
Keyword(s):  
Ground Penetrating Radar ◽  
Gamma Ray ◽  
Reservoir Rock ◽  
Rock Properties ◽  
Random Pattern ◽  
Log Data ◽  
Architectural Elements ◽  
Ground Penetrating ◽  
Gamma Ray Log

AbstractThe integrated application of advanced visualization techniques – validated against outcrop, core and gamma ray log data – was found to be crucial in characterizing the spatial distribution of fluvial facies and their inherent permeability baffles to a centimetre-scale vertical resolution. An outcrop/behind outcrop workflow was used, combining the sedimentological analysis of a perennial deep braided outcrop with ground-penetrating radar profiles, behind outcrop optical and acoustic borehole imaging, and the analyses of dip tadpoles, core and gamma ray logs. Data from both the surface and subsurface allowed the recognition of two main architectural elements – channels and compound bars – and within the latter to distinguish between the bar head and tail and the cross-bar channel. On the basis of a well-constrained sedimentological framework, a detailed characterization of the gamma ray log pattern in the compound bar allowed several differences between the architectural elements to be identified, despite a general cylindrical trend. A high-resolution tadpole analysis showed that a random pattern prevailed in the channel, whereas in the bar head and tail the tadpoles displayed characteristic patterns that allowed differentiation. The ground-penetrating radar profiles aided the 3D reconstruction of each architectural element. Thus the application of this outcrop/behind outcrop workflow provided a solid database for the characterization of reservoir rock properties from outcrop analogues.

Fields of view of airborne gamma‐ray detectors

Geophysics ◽  
1979 ◽  
Vol 44 (8) ◽  
pp. 1447-1457 ◽  
Author(s):  
R. L. Grasty ◽  
K. L. Kosanke ◽  
R. S. Foote
Keyword(s):  
Count Rate ◽  
Sodium Iodide ◽  
Gamma Ray ◽  
Radioactive Source ◽  
Angular Sensitivity ◽  
Surface Areas ◽  
Relative Contribution ◽  
Gamma Ray Detectors ◽  
Ground Survey ◽  
Gamma Ray Detector

In planning and interpreting airborne gamma‐ray surveys, an important consideration is the relative contribution of surface areas of a homogeneous radioactive source to the detected radiation. Numerical calculations have shown that along a flight line the width of the strip that produces a fixed percentage of the detected radiation is significantly less than the diameter of the circle contributing the same percentage of the radiation detected by a stationary gamma‐ray detector. Experimental angular sensitivity measurements of typical sodium‐iodide detectors were incorporated into the calculations and showed that the results were not strongly dependent on the detector configuration. The results are shown to have applications in estimating the count rate from small sources and in the design of an optimum ground survey grid for test strips selected for the calibration of airborne gamma‐ray spectrometers.

Sign in / Sign up

Export Citation Format

Share Document