Temperature dependence of x-ray-induced photoconductivity in kapton and teflon

The x-ray induced photoconductivity in Kapton (Dupont polyimide) and Teflon over the temperature range 100--5000K was measured. The observed temperature dependence of the photoconductivity was strikingly different for the two materials. The qualitative behavior of the Kapton samples was consistent with the predictions of a model where the delayed photoconductivity signal is due to thermal release of trapped charge. With Teflon samples, the observed prompt conductivity was almost temperature independent, and a pronounced peak in the delayed component of the photoconductivity at about 3600K was observed. Changes in the occupation of deep trapping levels is discussed as a possible mechanism for the observed thermal quenching of the Teflon photoconductivity. (U.S.)