Airborne gamma‐ray spectrometric background estimation using full spectrum analysis

Geophysics ◽  
1992 ◽  
Vol 57 (2) ◽  
pp. 279-287 ◽  
Author(s):  
B. R. S. Minty
Keyword(s):  
Gamma Ray ◽  
Atmospheric Radiation ◽  
Compton Continuum ◽  
Full Spectrum ◽  
Background Estimation ◽  
Potassium Sources ◽  
Energy Formula ◽  
A New Technique ◽  
The Vertical Distribution ◽  
Atmospheric Radon

We have developed a new technique for estimating airborne gamma‐ray spectrometric backgrounds. The background comes from three sources, namely aircraft, cosmic and atmospheric (radon) radiation. The aircraft and cosmic components are independently estimated by suitable calibration and the monitoring of a 3–6 MeV “cosmic” channel. Multichannel observations of the spectra are used to estimate the atmospheric background directly based on the observation that for gamma‐ray counts above the Compton continuum, the low energy [Formula: see text] photopeak at 0.609 MeV for atmospheric radiation suffers far less attenuation relative to the [Formula: see text] peak at 1.76 MeV than is the case for radiation from uranium in the ground. Since thorium and potassium sources do not contribute appreciably to these peak countrates, they can be used to calculate the contributions of radon and uranium to the observed spectrum. The technique appears to be less susceptible to errors due to the effects of variations in the vertical distribution of airborne radon and its daughters than upward‐looking detector techniques.

Multichannel models for the estimation of radon background in airborne gamma‐ray spectrometry

Geophysics ◽  
1998 ◽  
Vol 63 (6) ◽  
pp. 1986-1996 ◽  
Author(s):  
Brian R. S. Minty
Keyword(s):  
Gamma Ray ◽  
Weighted Least Squares ◽  
Spectral Ratio ◽  
Ratio Method ◽  
Gamma Ray Spectrometry ◽  
Minimization Method ◽  
Full Spectrum ◽  
Spectrometric Data ◽  
Spectral Ratio Method ◽  
Atmospheric Radon

Adequate background correction is a crucial step in processing airborne gamma‐ray spectrometric data because any errors are amplified during subsequent processing procedures. Two multichannel models for the estimation of atmospheric radon background are proposed. The spectral‐ratio method uses the relative heights of uranium (U) series photopeaks to estimate the contribution of atmospheric radon to observed spectra. The full‐spectrum method estimates the atmospheric radon contribution through the weighted least‐squares fitting of potassium (K), U, thorium (Th), and radon component spectra to the observed spectra. Both the spectral‐ratio and full‐spectrum methods are adequately calibrated through the estimation of component spectra from calibration experiments on the ground using radioactive calibration sources and wood to simulate the attenuation of gamma rays by air. The simulated heights used in these calibrations must be mapped onto real heights through calibration flights over an airborne calibration range. The spectral‐ratio method is also adequately calibrated using a heuristic calibration procedure. An iterative minimization method is used to find the optimum values of the calibration constants such that the radon background over suitable calibration lines is best removed.

scholarly journals Experimental and Simulated Spectral Gamma-Ray Response of a NaI(Tl) Scintillation Detector used in Airborne Gamma-Ray Spectrometry

2021 ◽  
Author(s):  
David Breitenmoser
Keyword(s):  
Monte Carlo ◽  
Gamma Ray ◽  
Radiation Transport ◽  
Natural Uranium ◽  
Detector Response ◽  
Gamma Ray Spectrometry ◽  
Response Analysis ◽  
Maximum Relative Error ◽  
Potassium Sources ◽  
Significant Difference

<p>The objective of this work is to simulate the spectral gamma-ray response of NaI(Tl) scintillation detectors for airborne gamma-ray spectrometry (AGRS) using Monte Carlo radiation transport codes. The study is based on a commercial airborne gamma-ray spectrometry detector system with four individual NaI(Tl) scintillation crystals and a total volume of 16.8 l. Monte Carlo source-detector simulations were performed in an event-by-event mode with the commercial multi-purpose transport codes MCNP6.2 and FLUKA. Validation measurements were conducted using <sup>241</sup>Am, <sup>133</sup>Ba, <sup>60</sup>Co, <sup>137</sup>Cs and <sup>152</sup>Eu radiation sources with known activities and source-detector geometries. Energy resolution functions were derived from these measurements combined with additional measurements of natural Uranium, Thorium and Potassium sources. The simulation results are in good agreement with the experimental data with a maximum relative error in the full-energy peak counts of 10%. In addition, no significant difference between the two Monte Carlo radiation transport codes was found with respect to a 95% confidence level. The validated detector model presented herein can be adopted for angular detector response analysis and calibration computations relating radionuclide activity concentrations with spectral detector counts.</p>

Kernel-Based Machine Learning for Background Estimation of NaI Low-Count Gamma-Ray Spectra

2013 ◽  
Vol 60 (3) ◽  
pp. 2209-2221 ◽  
Author(s):  
M. Alamaniotis ◽  
J. Mattingly ◽  
L. H. Tsoukalas
Keyword(s):  
Machine Learning ◽  
Gamma Ray ◽  
Background Estimation

The altitude dependence of terrestrial gamma‐ray spectra: A simple model

Geophysics ◽  
1986 ◽  
Vol 51 (11) ◽  
pp. 2108-2116 ◽  
Author(s):  
R. C. Bailey
Keyword(s):  
Gamma Rays ◽  
Spectral Dependence ◽  
Gamma Ray ◽  
Spectral Shape ◽  
Effective Height ◽  
Accurate Knowledge ◽  
Spectral Contribution ◽  
Altitude Dependence ◽  
Spectral Components ◽  
Atmospheric Radon

Accurate airborne multichannel gamma‐ray surveys require accurate knowledge of the spectral shapes of the natural radioelements and their variation with height. Simple physical considerations suggest a model with two spectral components for each radioelement, in which the first component decays into the second with increasing height. The two spectral components are approximately identified with gamma rays that have been scattered and those that have not been scattered since entering the atmosphere, although this interpretation is irrelevant to the applications of the model. The model’s analytic representation of spectral dependence on height yields an explicit formula for the effective height of the detector as deduced from spectral shape. Atmospheric radon is shown to produce a negative effective height, which implies a possible method for estimating atmospheric radon directly rather than from spectral shape. An extension of this approach gives an approximate formula for estimating the spectral contribution of an arbitrarily stratified distribution of radon.

scholarly journals GRB 090227B: A FIRST EXAMPLE OF A GENUINE SHORT GRB

2013 ◽  
Vol 23 ◽  
pp. 248-253
Author(s):  
M. MUCCINO ◽  
C. L. BIANCO ◽  
L. IZZO ◽  
A. V. PENACCHIONI ◽  
R. RUFFINI
Keyword(s):  
Total Energy ◽  
Effective Temperature ◽  
Thermal Process ◽  
Gamma Ray ◽  
Black Body ◽  
Lorentz Factor ◽  
Gamma Ray Bursts ◽  
Gradual Transition ◽  
Natural Explanation ◽  
Energy Formula

In the context of the Fireshell scenario Gamma-Ray Bursts (GRBs) find a natural explanation in the values of three main parameters: the energy of the emitting e± plasma [Formula: see text], the baryon load B, and the density of the Circum-Burst Medium (CBM) nCBM. For B≲10-5, the GRB consists of a spike-like emission without any afterglow: a genuine short burst. GRB 090227B is the first recognized genuine short GRB. Its analysis reveals that the transparency emission is not a pure thermal process, owing to a non-gradual transition between the optically thick and the optically thin phases. Within our theory we have recovered the original thermal spectrum of the e± plasma, namely the effective Black body (BB); we indeed have determined the parameters of the Fireshell model, including the redshift. Setting a baryon load B = 10-6, we obtain the effective temperature [Formula: see text], the Lorentz factor at transparency Γ = 12852, and the total energy [Formula: see text]. The estimated redshift is z = 4.07±0.36.

scholarly journals Study of cosmogenic activation in copper for rare event search experiments

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Ze She ◽  
Zhi Zeng ◽  
Hao Ma ◽  
Qian Yue ◽  
Mingkun Jing ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Rare Event ◽  
Background Level ◽  
Germanium Detectors ◽  
Production Rates ◽  
Background Estimation ◽  
Gamma Ray Spectrometer ◽  
Detector Structure ◽  
Cosmogenic Activation ◽  
The Impact

AbstractRare event search experiments using germanium detectors are performed in underground laboratories to minimize the background induced by cosmic rays. However, the cosmogenic activation of cupreous detector components on the ground generates long half-life radioisotopes and contributes to the background level. We measured cosmogenic activation with 142.50 kg of copper bricks after 504 days of exposure at an altitude of 2469.4 m outside the China Jinping Underground Laboratory (CJPL). The specific activities of the cosmogenic nuclides produced in the copper bricks were measured using a low-background germanium gamma-ray spectrometer at CJPL. The production rates at sea level, in units of nuclei/kg/day, were $${18.6 \pm 2.0}$$ 18.6 ± 2.0 for $${^{54}}$$ 54 Mn, $${9.9 \pm 1.3}$$ 9.9 ± 1.3 for $${^{56}}$$ 56 Co, $${48.3 \pm 5.5}$$ 48.3 ± 5.5 for $${^{57}}$$ 57 Co, $${51.8 \pm 2.5}$$ 51.8 ± 2.5 for $${^{58}}$$ 58 Co, and $${39.7 \pm 5.7}$$ 39.7 ± 5.7 for $${^{60}}$$ 60 Co. The measurement will help to constrain cosmogenic background estimation for rare event searches using copper as a detector structure and shielding material. Based on the measured production rates, the impact of the cosmogenic background in cupreous components of germanium detectors on the next generation CDEX-100 experiment was assessed with the expected exposure history above ground.

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