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The mass attenuation coefficient (MAC), effective atomic number (Zeff), and effective electron density (Neff) values of soils in mangrove forests across the Philippine islands were investigated. In addition, ENDF/B-VI.8 cross-section data library was used for interpolating Zeff and Neff values. Photon energies considered in this study ranged from 59.5-1332 keV. MAC values were obtained using MCNP5 and PHITS Monte Carlo (MC) simulations and were found to be in good agreement with XCOM and values in literature. Results for Zeff were in good agreement with values obtained using Phy-X/ZeXTRa program. Each shielding parameter was investigated as a function of SiO2 concentrations. [ABSTRACT FROM AUTHOR]

A method for estimating source strength measurements of californium neutron sources is presented, based on the model of 252 Cf, 250 Cf, and 248 Cm decay. This is combined with the Monte Carlo method (MCM) of propagating uncertainties. Californium sources were categorized into two types: Sort-A are those with most input quantities known while Sort-B are sources with only the mass at a certain reference date known. For Sort-A, the spread of all input quantities was estimated with Gaussian distribution and the deterministic 1st order GUM uncertainty propagation is applied to validate the MCM results. While, for Sort-B with inputs that have non-Gaussian distributions, only MCM is applied to evaluate uncertainties. Results show that for californium sources that are 25 y or older, a simple 252 Cf decay correction is imprecise due to the contribution of 250 Cf and 248 Cm. The MCM was also shown to be a robust technique for uncertainty analysis that provides results for both Gaussian and non-Gaussian distributions. Moreover, the time-dependence of the contributors in the source strength and the corresponding uncertainties are presented. When exceedingly low uncertainties are not required, the calculation techniques presented in this work may serve as an alternative to actual measurements, which tend to be expensive., (Copyright © 2020 Elsevier Ltd. All rights reserved.)