title: Different methods of mass attenuation coefficient evaluation: Influences in the measurement of some soil physical properties.
abstract: The mass attenuation coefficients of Brazilian soils (μs) and water (μw) were measured and calculated at 59.5keV ((241)Am) photon energy. The μs and μw experimental values were compared using XCOM and Monte Carlo computer codes (FLUKA, GEANT4 and MCNP). The influence of different methods of µ evaluation on the measurement of soil bulk density (ρs) and soil water content (θ) distributions and soil water retention (SWRC) was investigated. ρs and θ distributions were analyzed by using computed tomography (CT). Distinct ρs distributions were obtained even for similar µs values measured among methods. θ distributions were also greatly influenced by the different methods of μw evaluation. Regarding the SWRC, the results exhibited great differences in the region of structural pores, which directly affected the pore size distribution.
authors.affiliation: Laboratory of Soil Physics and Environmental Sciences, Department of Physics, State University of Ponta Grossa (UEPG), CEP. 84.030-900 Ponta Grossa, PR, Brazil. Electronic address: lfpires@uepg.br.
authors.forename: L F
authors.initials: LF
authors.lastname: Pires
authors.affiliation: Experimental Nuclear Physics Department, Nuclear Research Centre, P.O. 13759 Cairo, Egypt.
authors.forename: M E
authors.initials: ME
authors.lastname: Medhat
keywords: Computed tomography; Monte Carlo simulation (FLUKA, GEANT4 and MCNP); Soil bulk density; Soil porosity; Soil water retention curve; XCOM