Evaluation of gamma-ray and neutron attenuation properties of some polymers

TLDR

PVDC and PTFE have higher effective atomic numbers than the other polymers, whereas PA‑6 has the lowest. The study measured gamma‑ray attenuation of eight polymers across 81–1333 keV and calculated theoretical fast‑neutron removal cross sections to assess neutron attenuation. Gamma‑ray attenuation was measured with a high‑resolution HPGe detector in transmission geometry and the experimental linear attenuation coefficients were compared to WinXCOM theoretical values. All polymers exhibit a rapid drop in linear attenuation coefficient at low energies, a slower decline between 267 keV and 835 keV, PTFE shows the greatest gamma‑photon attenuation per half‑value layer, and the fast‑neutron removal cross sections are similar across polymers, ranging from 0.0706 to 0.1151 cm⁻¹.

Abstract

In the present work, we determined the gamma-ray attenuation characteristics of eight different polymers(Polyamide (Nylon 6) (PA-6), polyacrylonitrile (PAN), polyvinylidenechloride (PVDC), polyaniline (PANI), polyethyleneterephthalate (PET), polyphenylenesulfide (PPS), polypyrrole (PPy) and polytetrafluoroethylene (PTFE)) using transmission geometry utilizing the high resolution HPGe detector and different radioactive sources in the energy range 81–1333 keV. The experimental linear attenuation coefficient values are compared with theoretical data (WinXCOM data). The linear attenuation coefficient of all polymers reduced quickly with the increase in energy, at the beginning, while decrease more slowly in the region from 267 keV to 835 keV. The effective atomic number of PVDC and PTFE are comparatively higher than the Zeff of the remaining polymers, while PA-6 possesses the lowest effective atomic number. The half value layer results showed that PTFE (C2F4, highest density) is more effective to attenuate the gamma photons. Also, the theoretical results of macroscopic effective removal cross section for fast neutrons (∑R) were computed to investigate the neutron attenuation characteristics. It is found that the ∑R values of the eight investigated polymers are close and ranged from 0.07058 cm−1 for PVDC to 0.11510 cm−1 for PA-6.