Do We Accurately Know the Radioactive Inventory Inside a Waste Package? A Résumé After 5 Years Experience in the Development and Operation of Advanced Gamma Scanning Systems

2001 ◽  
Author(s):  
H.-J. Sanden ◽  
G. Caspary ◽  
K. Kroth ◽  
M. Bruggeman ◽  
T. Bücherl
Keyword(s):  
Quality Control ◽  
Radioactive Waste ◽  
Gamma Ray ◽  
Source Distribution ◽  
Research Projects ◽  
Waste Package ◽  
Gamma Ray Attenuation ◽  
The Difference ◽  
Scanning Systems ◽  
Gamma Scanning

Abstract This paper gives a survey of the main results of research projects performed by members of ENTRAP to improve gamma-ray scanning techniques for radioactive waste packages. Performance characteristics, advantages and restrictions of different assay procedures and correction techniques investigated in these projects are discussed. Case studies are presented which demonstrate the difference in performance between ‘standard’ and ‘improved’ assay techniques. Consideration is also given to bias effects resulting from a limited knowledge on gamma-ray attenuation and/or source distribution in the waste matrix. Procedures and tools are presented which may help to decrease respective bias effects or to assess the overall uncertainty. The achievements emphasise that quality control of assay results requires, in nearly all applications, that additional assay techniques are implemented in order to verify the validity of conventional gamma-ray scanning methods.

scholarly journals The electromagnetic radiation whose decay violates the inverse-square law: detailed mathematical treatment of an experimentally realized example

2019 ◽  
Vol 85 (3) ◽  
Author(s):  
Houshang Ardavan
Keyword(s):  
Gamma Ray ◽  
Electric Polarization ◽  
Rate Of Change ◽  
Source Distribution ◽  
Mathematical Treatment ◽  
Polarization Current ◽  
Radiation Beam ◽  
Conventional Radiation ◽  
The Difference ◽  
Temporal Rate

I analyse and numerically evaluate the radiation field generated by an experimentally realized embodiment of an electric polarization current whose rotating distribution pattern moves with linear speeds exceeding the speed of light in vacuum. I find that the flux density of the resulting emission (i) has a dominant value and is linearly polarized within a sharply delineated radiation beam whose orientation and polar width are determined by the range of values of the linear speeds of the rotating source distribution, and (ii) decays with the distance $d$ from the source as $d^{-\unicode[STIX]{x1D6FC}}$ in which the value of $\unicode[STIX]{x1D6FC}$ lies between $1$ and $2$ (instead of being equal to $2$ as in a conventional radiation) across the beam. In that the rate at which boundaries of the retarded distribution of such a source change with time depends on its duration monotonically, this is an intrinsically transient emission process: temporal rate of change of the energy density of the radiation generated by it has a time-averaged value that is negative (instead of being zero as in a conventional radiation) at points where the envelopes of the wave fronts emanating from the constituent volume elements of the source distribution are cusped. The difference in the fluxes of power across any two spheres centred on the source is in this case balanced by the change with time of the energy contained inside the shell bounded by those spheres. These results are relevant not only to long-range transmitters in communications technology but also to astrophysical objects containing rapidly rotating neutron stars (such as pulsars) and to the interpretation of the energetics of the multi-wavelength emissions from sources that lie at cosmological distances (such as radio and gamma-ray bursts). The analysis presented in this paper is self-contained and supersedes my earlier works on this problem.

scholarly journals The efficiency calibration for local manufacturing gamma scanning systems of radioactive waste drums

2018 ◽  
Vol 15 (35) ◽  
pp. 100-108
Author(s):  
Saad Salih Dawood
Keyword(s):  
Radioactive Waste ◽  
Radioactive Source ◽  
Assay Method ◽  
Nondestructive Assay ◽  
Local Manufacturing ◽  
Cylindrical Holes ◽  
Scanning Systems ◽  
Waste Drums ◽  
Gamma System ◽  
Gamma Scanning

The Local manufacturing scanning gamma system designed in Tuwaitha site for nondestructive assay method of radioactive waste drums, where it consist of two main parts with their belongings for controlling the of detector and drum movements up-down and rotation respectively. The volume of the used drum is 220 L with 85 cm height. The drum filled with Portland cement. Six cylindrical holes were made within cement drum and distributed in radial arrangement.The152Eu source inserted in these holes individually, to measure the average angular count rate of gamma radiation. The full energy efficiency value for geometry of drum and detector is computed for thirteen photo peaks. The average efficiency represented by the curve of these peaks indicated the decreasing of efficiency value with increasing the cement thickness and the distance between the detector and the location of radioactive source inside the drum.

Eine iterative Strategie zur Bestimmung der Quellverteilung bei der Einzelphotonen-Tomographie mit einer rotierenden Gammakamera (SPECT)

1988 ◽  
Vol 27 (04) ◽  
pp. 140-146 ◽  
Author(s):  
W. Eschner ◽  
M. Bähre ◽  
E. Voth ◽  
G. Nolte ◽  
H. Luig
Keyword(s):  
Gamma Ray ◽  
Brain Perfusion ◽  
Low Noise ◽  
Emission Tomography ◽  
Source Distribution ◽  
Scintigraphic Imaging ◽  
Brain Perfusion Imaging ◽  
Phantom Measurements ◽  
Gamma Ray Attenuation

A new iterative strategy for determination of the source distribution in singlephoton emission tomography (SPECT) simulates mathematically the scintigraphic imaging process during direction sum computation. Limited spatial resolution and gamma-ray attenuation are taken into account using simplifying approximations. Highly resolved low-noise tomograms without obvious artifacts are obtained. Results of phantom measurements as well as cases of thyroid and brain perfusion imaging are presented to demonstrate the capabilities of the method.

scholarly journals Gamma-Ray Attenuation to Evaluate Soil Porosity: An Analysis of Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Luiz F. Pires ◽  
André B. Pereira
Keyword(s):  
Gamma Ray ◽  
Particle Density ◽  
Pore Space ◽  
Physical Property ◽  
Soil Bulk Density ◽  
Soil Porosity ◽  
Porous System ◽  
Soil Pore Space ◽  
Gamma Ray Attenuation ◽  
Dry Soil

Soil porosity (ϕ) is of a great deal for environmental studies due to the fact that water infiltrates and suffers redistribution in the soil pore space. Many physical and biochemical processes related to environmental quality occur in the soil porous system. Representative determinations ofϕare necessary due to the importance of this physical property in several fields of natural sciences. In the current work, two methods to evaluateϕwere analyzed by means of gamma-ray attenuation technique. The first method uses the soil attenuation approach through dry soil and saturated samples, whereas the second one utilizes the same approach but taking into account dry soil samples to assess soil bulk density and soil particle density to determineϕ. The results obtained point out a good correlation between both methods. However, whenϕis obtained through soil water content at saturation and a 4 mm collimator is used to collimate the gamma-ray beam the first method also shows good correlations with the traditional one.

Gamma-ray attenuation behaviors of hematite doped polymer composites

2020 ◽  
Vol 129 ◽  
pp. 103504 ◽  
Author(s):  
Mehmet Fatih Turhan ◽  
Ferdi Akman ◽  
Hasan Polat ◽  
Mustafa Recep Kaçal ◽  
İskender Demirkol
Keyword(s):  
Polymer Composites ◽  
Gamma Ray ◽  
Gamma Ray Attenuation ◽  
Doped Polymer

Measurement of pulmonary edema in intact dogs by transthoracic gamma-ray attenuation

1979 ◽  
Vol 47 (6) ◽  
pp. 1228-1233 ◽  
Author(s):  
D. S. Simon ◽  
J. F. Murray ◽  
N. C. Staub
Keyword(s):  
Pulmonary Edema ◽  
Time Course ◽  
Gamma Ray ◽  
High Sensitivity ◽  
Lung Edema ◽  
Lung Water ◽  
Vascular Congestion ◽  
Isolated Lung ◽  
Wide Range ◽  
Gamma Ray Attenuation

We evaluated the attenuation of the 122 keV gamma ray of cobalt-57 across the thorax of anesthetized dogs as a method for following the time course of lung water changes in acute pulmonary edema induced by either increased microvascular permeability or increased microvascular hydrostatic pressure. The gamma rays traversed the thorax centered on the seventh rib laterally where the lung mass in the beam path was greatest. Calibration measurements in isolated lung lobes demonstrated the high sensitivity and inherent accuracy of the method over a wide range of lung water contents. In control dogs reproducibility averaged +/-3%. Increased permeability edema led to large rapid increases in the transthoracic gamma ray attenuation (TGA), while increased pressure caused an immediate, modest increase in TGA (vascular congestion) followed by a slow further increase over 2 h. There was a fairly good correlation between the increase in extravascular lung water and the change in TGA. The method is simple, safe, and noninvasive and appears to be useful for following the time course of lung water accumulation in generalized lung edema in anesthetized animals.

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