Temperature Dependence of Radiation Induced Conductivity in Insulators
American Institute of Physics Conference Proceedings Series
Floyd D. McDaniel, Barney L. Doyle
American Institute of Physics
This study measures Radiation Induced Conductivity (RIC) of Low Density Polyethylene (LDPE) over temperatures ranging from ~110 K to ~350 K. RIC occurs when incident ionizing radiation deposits energy and excites electrons into the conduction band of insulators. Conductivity was measured when a voltage was applied across vacuum-baked, thin film LDPE polymer samples in a parallel plate geometry. RIC was calculated as the difference in sample conductivity under no incident radiation and under an incident ~4 MeV electron beam at low incident fluxes of 10−4–10−1 Gr/sec. The steady-state RIC was found to agree well with the standard power law relation, RIC = kRIC· between conductivity, and adsorbed dose rate, . Both the proportionality constant, kRIC, and the power, , were found to be temperature dependant above ~250 K, with behavior consistent with photoconductivity models developed for localized trap states in disordered semiconductors. Below ~250 K, kRIC and exhibited little change. The observed difference in temperature dependence might be related to a structural phase transition seen at T~256 K in prior studies of mechanical and thermodynamic properties of LDPE. ©2009 American Institute of Physics
JR Dennison, Jodie Gillespie, Joshua Hodges, RC Hoffmann, J Abbott, Alan W. Hunt and Randy Spalding, “Radiation Induced Conductivity of Highly-Insulating Spacecraft Materials,” in Application of Accelerators in Research and Industry, American Institute of Physics Conference Proceedings Series, Vol. 1099, ed. Floyd D. McDaniel and Barney L. Doyle,(American Institute of Physics, Melveille, NY, 2009), pp. 203-208
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