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.

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 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.

scholarly journals Solar flare detection method using Rn-222 radioactive source

2020 ◽  
Vol 5 (2) ◽  
pp. 159-166
Author(s):  
Jonathan Walg ◽  
Anatoly Rodnianski ◽  
Itzhak Orion
Keyword(s):  
Solar Flare ◽  
Count Rate ◽  
Gamma Ray ◽  
Neutrino Flux ◽  
Radioactive Source ◽  
Decay Rates ◽  
Radioactive Nuclide ◽  
The Sun ◽  
Order Of Magnitude ◽  
Flux Increase

Solar neutrino detection is known to be a very challenging task, due to the minuscule absorption cross-section and mass of the neutrino. One research showed that relative large solar-flares affected the decay-rates of Mn-54 in December 2006. Since most the radiation emitted during a solar flare are blocked before reaching the earth surface, it should be assumed that such decay-rate changes could be due to neutrino flux increase from the sun, in which only neutrinos can penetrate the radionuclide. This study employs the Rn-222 radioactive source for the task of solar flare detection, based on the prediction that it will provide a stable gamma ray counting rate. In order to ascertain counting stability, three counting systems were constructed to track the count-rate changes. The Rn-222 count-rate measurements showed several radiation counting dips, indicating that the radioactive nuclide can be affected by order of magnitude neutrino flux change from the sun. We conclude that using the cooled Radon source obtained the clearest responses, and therefore this is the preferable system for detecting neutrino emissions from a controlled source.

scholarly journals Positron clouds within thunderstorms

2015 ◽  
Vol 81 (4) ◽  
Author(s):  
Joseph R. Dwyer ◽  
David M. Smith ◽  
Bryna J. Hazelton ◽  
Brian W. Grefenstette ◽  
Nicole A. Kelley ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Flat Plate ◽  
Positron Annihilation ◽  
Gamma Rays ◽  
Data Model ◽  
Count Rate ◽  
Gamma Ray ◽  
Energy Spectra ◽  
Gamma Ray Detectors ◽  
Plate Antenna

We report the observation of two isolated clouds of positrons inside an active thunderstorm. These observations were made by the Airborne Detector for Energetic Lightning Emissions (ADELE), an array of six gamma-ray detectors, which flew on a Gulfstream V jet aircraft through the top of an active thunderstorm in August 2009. ADELE recorded two 511 keV gamma-ray count rate enhancements, 35 s apart, each lasting approximately 0.2 s. The enhancements, which were approximately a factor of 12 above background, were both accompanied by electrical activity as measured by a flat-plate antenna on the underside of the aircraft. The energy spectra were consistent with a source mostly composed of positron annihilation gamma rays, with a prominent 511 keV line clearly visible in the data. Model fits to the data suggest that the aircraft was briefly immersed in clouds of positrons, more than a kilometre across. It is not clear how the positron clouds were created within the thunderstorm, but it is possible they were caused by the presence of the aircraft in the electrified environment.

Introduction: Seventy Years of Calorimetry

2018 ◽  
Author(s):  
Richard Wigmans
Keyword(s):  
Gamma Ray ◽  
Experimental Techniques ◽  
Gamma Ray Detectors ◽  
History Of

The history of calorimetry is described, starting with the small scintillating crystals that were used as nuclear gamma ray detectors, to the multi-ton instruments that form the heart of modern experiments at colliding-beam accelerators. The different experimental techniques that are used for generating signals are reviewed.

scholarly journals The STACEE ground-based gamma-ray detector

2005 ◽  
Author(s):  
D.M. Gingrich ◽  
L.M. Boone ◽  
D. Bramel ◽  
J. Carson ◽  
C.E. Covault ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Detector

CdTe-based crystals with Mg, Se, or Mn as materials for X and gamma ray detectors: Selected physical properties

2021 ◽  
pp. 100543
Author(s):  
Andrzej Mycielski ◽  
Aneta Wardak ◽  
Dominika Kochanowska ◽  
Marta Witkowska-Baran ◽  
Michał Szot ◽  
...  
Keyword(s):  
Physical Properties ◽  
Gamma Ray ◽  
Gamma Ray Detectors

scholarly journals Soft gamma-ray detector for the ASTRO-H Mission

2012 ◽  
Author(s):  
Shin Watanabe ◽  
Hiroyasu Tajima ◽  
Yasushi Fukazawa ◽  
Roger Blandford ◽  
Teruaki Enoto ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Detector

Bayesian deconvolution of gamma‐ray logs

Geophysics ◽  
1987 ◽  
Vol 52 (11) ◽  
pp. 1535-1546 ◽  
Author(s):  
Ping Sheng ◽  
Benjamin White ◽  
Balan Nair ◽  
Sandra Kerford
Keyword(s):  
High Frequency ◽  
Gamma Ray ◽  
Simulated Data ◽  
Field Measurements ◽  
Bayesian Optimization ◽  
Frequency Noise ◽  
High Frequency Noise ◽  
Data Application ◽  
Gamma Ray Detector ◽  
Gamma Ray Log

The spatial resolution of gamma‐ray logs is defined by the length 𝓁 of the gamma‐ray detector. To resolve thin beds whose thickness is less than 𝓁, it is generally desirable to deconvolve the data to reduce the averaging effect of the detector. However, inherent in the deconvolution operation is an amplification of high‐frequency noise, which can be a detriment to the intended goal of increased resolution. We propose a Bayesian statistical approach to gamma‐ray log deconvolution which is based on optimization of a probability function which takes into account the statistics of gamma‐ray log measurements as well as the empirical information derived from the data. Application of this method to simulated data and to field measurements shows that it is effective in suppressing high‐frequency noise encountered in the deconvolution of gamma‐ray logs. In particular, a comparison with the least‐squares deconvolution approach indicates that the incorporation of physical and statistical information in the Bayesian optimization process results in optimal filtering of the deconvolved results.

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