Calculation of the systematic error and correction factors in gamma waste assay system

Dũng, Trần Quốc

doi:10.1016/0306-4549(96)00059-x

Cited by 20 publications

(2 citation statements)

References 1 publication

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“…The different 'hot spots' distances from the center of the drum are the main reason for wide reading variations when the drum is rotated. The different positions of the 'hot spots' are the main cause of activity estimation errors [1]. The first standard correction procedure handles gamma attenuation using density estimation.…”

Section: Introductionmentioning

confidence: 99%

Improving Activity Estimation in Passive Gamma Scanning for Radioactive Waste Drums

Vax¹,

Marcus²,

Mazor³

et al. 2020

EPJ Web Conf.

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A method to improve radioactive waste drum activity estimation in Segmented Gamma Scanning (SGS) systems was developed for homogenous content. We describe a method to quantify the activity of spatially distributed gamma-emitting isotopes (‘hot spots’) in homogenous content waste drums without the use of a collimator. Instead of averaging all the detector's readings we treat it as many different spatial samples as if we have multiple detectors surrounding the waste drum ("virtual detectors"). From these readings, we form a general linear model. Next, we derive the Maximum Likelihood Estimator (MLE) for the multiple sources position and activity. We solve this hyper-dimensional search problem using an Alternating Projections (AP) technique which transforms the problem into a simpler one-dimensional maximization problem. We tested this method using a mathematical simulation with a various number of sources, at random activities and positions for several energy bands. The preliminary results are consistent and show large improvement of the accuracy with comparison to industrial SGS systems and the same accuracy as new methods which exploits the spatial samples. Furthermore, since this method eliminates the need for heavy led collimator, none of the sources is blocked for the whole measurement period, which provides increased count rates and decreases the total measurement time.

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Section: Introductionmentioning

confidence: 99%

Improving Activity Estimation in Passive Gamma Scanning for Radioactive Waste Drums

Vax¹,

Marcus²,

Mazor³

et al. 2020

EPJ Web Conf.

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show abstract

“…However, the systematic error of SGS is large because of the unknown spatial distribution of the radioactive sources and matrix heterogeneity. Especially, non-uniform distribution of radiation sources frequently causes the largest error; moreover, the inhomogeneity of matrix also enlarges the measurement error (Dung, 1997(Dung, , 1998. There are also some improved SGS techniques (Anh et al, 2005;Bai et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

ICONE19-43539 Evaluation of Performance of an Improved Segmented Gamma Scanning Method for the Activity Determination of Radioactive Waste Drums

Liu

Wang

Bai

et al. 2011

ICONE

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Radioactive waste must be characterized to determine the radioactive content before the storage, transportation and final disposition. Segmented gamma scanning (SGS) is the most widely used method for non-destructive determination of the activity in gamma contaminated waste drums. However, the systematic error of SGS is large because of the unknown spatial distribution of the radioactive sources and matrix heterogeneity. In this paper, an improved SGS method which excludes the assumption of homogenous distribution of the radioactive sources has been studied for the assay of waste drums mainly containing organic materials. This method uses two identical detectors with one set at off-center position to scan the drum, aiming at finding out the equivalent radius of radioactive sources in each segment by analyzing the different responses of the two detectors. In order to evaluate the performance of this method, calculation work has been carried out by simulating a measurement system. Simulation results for cases of different radioactivity distributions in waste drum are presented and compared with those of traditional SGS, which shows that the relative errors of the improved SGS method for the cases of point source in homogenous matrices are less than 31%, and it also can give much better results than traditional SGS for the cases of sources in heterogeneous matrices.

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An efficiency calibration method of segmented gamma scanning in reconstructing radioactive waste drum activity

Zheng,

Tuo,

Wang

et al. 2024

J. Korean Phys. Soc.

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Calculation of the systematic error and correction factors in gamma waste assay system

Cited by 20 publications

References 1 publication

Improving Activity Estimation in Passive Gamma Scanning for Radioactive Waste Drums

Improving Activity Estimation in Passive Gamma Scanning for Radioactive Waste Drums

ICONE19-43539 Evaluation of Performance of an Improved Segmented Gamma Scanning Method for the Activity Determination of Radioactive Waste Drums

An efficiency calibration method of segmented gamma scanning in reconstructing radioactive waste drum activity

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