Hemispherical reflectance of PTFE + 10% wt. Fe Doped CNTs at simulated GEO electron irradiation conditions

Abstract

This paper summarizes reflectivity changes of PTFE + 10% wt. Fe doped CNTs composite samples with different thicknesses irradiated with high energy electrons to the total fluence of 7.5 × 1010 (e−/cm2). Reflectivity was measured in situ with the irradiation process in the JUMBO Space Environment Simulation and Spacecraft Charging Chamber at the Spacecraft Charging and Instrumentation Calibration Laboratory (SCICL, AFRL, Kirtland AFB, Albuquerque, NM, USA). Volume and surface resistivity measurements were recorded and calculated for test specimens using a Keithley 6517B Electrometer/High Resistance Meter system including a Keithley 8009 Resistivity Test Fixture, to measure current levels through the samples at a given voltage. System noise current was an average of 4.83 × 10−15 Amps. The current readings were captured in Labview, 6517A Meas-Scan – I.vi. The volume and the surface resistivity of the test specimens increased with increasing voltage. The conductivity of PTFE + 10% wt. Fe doped CNTs composite is increased by ten orders of magnitude as compared to the pristine PTFE, which can be attributed to the Fe doped CNTs additives.