On a new mechanism on γ -ray attenuation strengthened by new data

• Published in: Physica medica 2016-09, Vol.32, p.241-241
• Main Authors: Adamides, E, Kavadjiklis, A, Koutroubas, S.K, Moshonas, N, Tzedakis, A
• Format: Article
• Language: English
• Subjects: Radiology
• ISSN: 1120-1797
• DOI: 10.1016/j.ejmp.2016.07.505

Introduction We extended our previous detailed γ -ray attenuation measurements of60 Co γ rays in Pb and Fe to include also Cu, Hg, Al and H2 O. Purpose To introduce a new mechanism on γ -ray attenuation in matter. Materials and methods60 Co radiation source, slices of the absorbers and a Geiger Müller detector counter in broad and thin beam geometries. Experiments We performed detailed measurements of the detected radiation versus the thickness of the absorber and in parallel Monte Carlo simulations for each experiment. Results Monte-Carlo calculations were in qualitative agreement with experiment but quantitatively predicted systematically more radiation at the target. We related the differences with the parameters E γ and Zeff of the photoelectric absorption cross section which guided us to propose a new mechanism on the absorption of γ rays in matter. The γ radiation creates a huge number of electrons and ions passing through the absorber which form a steady state plasma condition increasing slightly the parameters Eb and Zeff of the lattice which in turn can increase measurably the photoelectric absorption thus restoring the agreement between Monte Carlo calculations and experiment. Conclusion Based on our large set of data which included absorbers in a wide range of Zeff we strengthened the need for a new mechanism on γ -ray absorption in matter.