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Optimal Exposure Time in Gamma-Ray Attenuation Experiments for Monitoring Time-Dependent Densities

Gonzalez-Nicolas, Ana ; Bilgic, Deborah; Kröker, Ilja; Mayar, Assem; Trevisan, Luca 1; Steeb, Holger; Wieprecht, Silke; Nowak, Wolfgang
1 Institut für Hydromechanik (IFH), Karlsruher Institut für Technologie (KIT)

Abstract:

Several environmental phenomena require monitoring time-dependent densities in porous media, e.g., clogging of river sediments, mineral dissolution/precipitation, or variably-saturated multiphase flow. Gamma-ray attenuation (GRA) can monitor time-dependent densities without being destructive or invasive under laboratory conditions. GRA sends gamma rays through a material, where they are attenuated by photoelectric absorption and then recorded by a photon detector. The attenuated intensity of the emerging beam relates to the density of the traversed material via Beer–Lambert’s law. An important parameter for designing time-variable GRA is the exposure time, the time the detector takes to gather and count photons before converting the recorded intensity to a density. Large exposure times capture the time evolution poorly (temporal raster error, inaccurate temporal discretization), while small exposure times yield imprecise intensity values (noise-related error, i.e. small signal-to-noise ratio). Together, these two make up the total error of observing time-dependent densities by GRA. Our goal is to provide an optimization framework for time-dependent GRA experiments with respect to exposure time and other key parameters, thus facilitating neater experimental data for improved process understanding. ... mehr


Zugehörige Institution(en) am KIT Institut für Hydromechanik (IFH)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2022
Sprache Englisch
Identifikator ISSN: 0169-3913, 1573-1634
KITopen-ID: 1000146546
Erschienen in Transport in Porous Media
Verlag Springer
Band 143
Heft 2
Seiten 463–496
Vorab online veröffentlicht am 28.04.2022
Nachgewiesen in Web of Science
Dimensions
Scopus
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