Radiation Damage and Recovery Properties of Common Plastics PEN (Polyethylene Naphthalate) and PET (Polyethylene Terephthalate) Using a 137Cs Gamma Ray Source Up To 1 MRad and 10 MRad

TL;DR

This study evaluates the radiation damage and recovery of common plastics PEN and PET, used as scintillators, after gamma ray exposure up to 10 MRad, revealing their potential for high-radiation environments.

Contribution

It provides the first detailed analysis of PEN and PET's radiation tolerance and recovery behavior at doses up to 10 MRad using gamma irradiation.

Findings

PEN retains over 46% of light after 10 MRad exposure.

PET recovers to over 80% of initial light emission after 60 days.

Both plastics show significant recovery, indicating suitability for high-radiation applications.

Abstract

Polyethylene naphthalate (PEN) and polyethylene teraphthalate (PET) are cheap and common polyester plastics used throughout the world in the manufacturing of bottled drinks, containers for foodstuffs, and fibers used in clothing. These plastics are also known organic scintillators with very good scintillation properties. As particle physics experiments increase in energy and particle flux density, so does radiation exposure to detector materials. It is therefore important that scintillators be tested for radiation tolerance at these generally unheard of doses. We tested samples of PEN and PET using laser stimulated emission on separate tiles exposed to 1 MRad and 10 MRad gamma rays with a 137Cs source. PEN exposed to 1 MRad and 10 MRad emit 71.4% and 46.7% of the light of an undamaged tile, respectively, and maximally recover to 85.9% and 79.5% after 5 and 9 days, respectively. PET exposed to 1 MRad and 10 MRad emit 35.0% and 12.2% light, respectively, and maximally recover to 93.5% and 80.0% after 22 and 60 days, respectively.