An enhanced differential evolution-based inverse radiation transport model for identification of unknown shielding layer thicknesses with gamma-ray spectrum

Identifying the geometric information of an object by analyzing the detected radiation fields is an important problem for national and global security. In the present work, an inverse radiation transport model, based on the enhanced differential evolution algorithm with global and local neighborhoods (IRT-DEGL), is developed to estimate the unknown layer thickness of the source/shield system with the gamma-ray spectrum. The framework is briefly introduced with the emphasis on handling the enhanced differential evolution algorithm. Using the simulated gamma-ray spectra, the numerical precision of the IRT-DEGL model is evaluated for one-dimensional source systems. Using the detected gamma-ray spectra, the inverse investigations for the unknown thicknesses of multiple shielding layers are performed. By comparing with the traditional gamma-ray absorption method, it is shown that the IRT-EDGL model can provide a much more accurate result and has great potential to be applied for the complicated systems.