Surface potential stability of large-area Teflon PTFE electret dosimeters of different thicknesses

The effects of charge polarity and thickness on the surface charge potential stability responses of large-area Teflon polytetrafluoroethylene (PTFE) discs electrostatically charged by a new "modified single point-to-plane corona poling rotating system" were studied. Large-area Teflon discs (6 cm diameter) with 0.2, 0.5 and 1 mm thicknesses were used to produce both negatively or positively charged Teflon discs, at the same charging conditions. The deposited charge potential stability of the Teflon discs of different thicknesses monitored by a non-contacting electrostatic voltmeter for an extended time were monitored up to 77 days. Some inter-related parameters such as surface charge potential and external electrostatic field, internal electrostatic field, surface charge density, and the storage duration were also studied. The thick large-area Teflon disc electrets produced provided a steady-state charge stability on either negative (0.2, 0.5 and 1 mm thick) or positive (1 mm thick) surface charge potentials for the long period studied. The Teflon electret discs produced demonstrated having the highest charge potential stability in thicker electrets (1 mm), either negative or positive polarity, with provision of high potential for different applications in general and radiation protection dosimetry in particular.