Results of Radiation-Induced Conductivity Testing of Europa Clipper Dielectric Materials

To quickly survey the charging characteristics of a wide range of dielectric materials being considered for use by the Europa Clipper spacecraft, JPL has developed a modified charge storage method test setup capable of measuring the magnitude of radiation-induced conductivity (RIC) and dark conductivity for up to 34 samples in parallel. We present material properties from a test campaign consisting of 129 measurements of 67 dielectric materials. In these measurements, bounding values of the RIC constant and dark conductivity ranged from <inline-formula> <tex-math notation="LaTeX">$1.4\times \cdot 10^{-20}$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$3.5\times \cdot 10^{-16} \,\,\mathrm {s} / {\mathrm {rad}\cdot \Omega \cdot \mathrm {cm}}$ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$2.2\times 10^{-20}$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$7.2\times 10^{-18} \,\,(\Omega \cdot \mathrm {cm})^{-1}$ </tex-math></inline-formula>, respectively, at 0 °C. For most of the materials tested, the data presented here are the first RIC and the first in-vacuum conductivity results published for these materials. The implementation of the new test system is discussed in a separate paper.