Time-Resolved Radiation-Induced Conductivity of Polyimide and Its Description Using the Multiple Trapping Formalism

Abstract

Polymer dielectrics subjected to intense radiation fluxes exhibit a radiation-induced conductivity (RIC). Polyimide is a good dielectric with excellent mechanical and thermal properties featuring high radiation resistance currently widely used in the spacecraft industry. Its RIC has been extensively studied in several laboratories. The purpose of the present study is to make a direct measurement of the RIC for both pulsed and continuous irradiation using a current sensing technique, which is contrary to the indirect method employing a surface-potential decay technique that is now preferred by spacecraft charging engineers. Our experiments are done in a small-signal regime excluding any recombination and dose effects. In combination with existing computer codes, we managed to develop further the conventional multiple trapping formalism and the RIC theory based on it. The main idea is to supplement an exponential trap distribution responsible for a dominant dispersive carrier transport in polymers with a small concentration of inherent deep traps which may or may not have an energy distribution. In line with this reasoning, we propose a tentative set of RIC model parameters for polyimide that accounts for the observed experimental data. The findings and their implications are discussed in a broad context of previous studies.

Radiation-Induced Transient Currents in Films of Poly(arylene ether ketone) Including Phthalide Moiety

“…RIC and TOF measurements: a scheme of the experimental setup for measuring polymer radiation-induced conductivity (RIC) and the time-of-flight (TOF) measurement is given on Figure 2 and detailed in [14]. All the polymers are readily soluble in a wide range of solvents (dichloromethane, chloroform, sym-tetrachloroethane, THF, dioxane, cyclohexanone, m-cresol, DMF, DMAA, etc.…”

“…RIC and TOF measurements: a scheme of the experimental setup for measuring polymer radiation-induced conductivity (RIC) and the time-of-flight (TOF) measurement is given on Figure 2 and detailed in [14].…”

“…RIC and TOF measurements: a scheme of the experimental setup for measuring polymer radiation-induced conductivity (RIC) and the time-of-flight (TOF) measurement is given on Figure 2 and detailed in [14]. The most valuable information has been obtained using 50 keV electrons (maximum range of about 40 µm) in pulse (1 ms) and continuous (exceeding approximately 0.1 s) irradiation modes, while the TOF application (electron energy 3-7 keV with a range less than 1.5 µm) was unsuccessful due to co-PAEK electronic properties.…”

Низкотемпературная Радиационная Электропроводность Полистирола Под Действием Электронов Низких Энергий

“…Тютнев, Е.Д. Пожидаев (РФВ) [1]: Значение j r приводится к значению РЭ согласно методике, описанной в [8]:…”

Theoretical Analysis of the Radiation-Induced Conductivity in Polymers Exposed to Pulsed and Continuous Electron Beams

“…An important turning point in these studies occurred during 2006-2017 when Tyutnev et al (see our latest paper [11]) developed a novel TOF technique; the so-called radiation induced variant employing pulses of 3 to 50 keV electrons provided by an electron gun ELA-65 (Orion, Moscow, Russia). In fact, this technique is a combination of three main modifications: TOF variant using 3 to 7 keV electrons producing carrier generation near an irradiated sample surface like in photo excitation; TOF-2 variant employing 50 keV electrons (the maximum energy available at the moment) for carrier generation in the bulk and TOF-1a method with the varying generation layer thickness.…”