Gamma‐Ray‐Induced Photoelectric Field Exacerbating Irradiation Damage in Ceramic Capacitors

Ceramic capacitors are widely used in radioactive environments and are known to take irradiation damages, but most of previous studies of its reliability focus on thermal or electrical issues, and much less is known about the microscopic mechanism of its irradiation damaging process. Herein, it is shown that the capacitance of ceramic capacitors can change significantly under continuous gamma‐ray irradiation. Moreover, it is noticed that ex situ measurements will underestimate the effect comparing with the in situ one. Herein, it is discovered that this difference is due to the gamma‐ray‐induced photoelectric field, which dissipate rapidly in ex situ measurements. While the impact of the photoelectric field on the capacitance can be seen in situ, due to the recombination of photogenerated carriers and annealing of defects after irradiation, ex situ measurements only account for a part of the irradiation damage. This discovery indicates that ex situ measurements, which are prevailing in irradiation damage studies, can miss critical information, and in situ measurements are necessary for revealing the mechanism of the process.