During radiation capacitor leakage resistance decreases and, as a result, the time constant of the circuit will also decrease. If the capacitor is in a critical timing circuit, the timing circuit may produce errors that affect system performance.
Wet tantalum capacitors have been used in space applications for over 40 years, from the early days of the manned space flight programs. Electrolytics are general avoided for space applications (although there are mil spec’ed electrolytics available).
Conductive polymer capacitors have been evaluated at total ionization dose (TID) test using a Cobalt 60 source up to 200k rad irradiation at dose rates of 500 rad/hr without impact to the part performance. Teflon (PTFE) has demonstrated a rather high susceptibility to radiation damage.
All dielectric materials become electrically conductive when exposed to ionizing radiation. From a circuit applications standpoint, the most important effect of radiation on a capacitor is the induced conductivity in the dielectric material. The amount of radiation-induced conductivity (RIC) can vary widely with dielectric material type.