In view of the threat of X-ray radiation produced by high-altitude nuclear explosions to polyimide (PI) materials, this paper develops a high-resolution X-ray in-situ irradiation space charge testing system. The space charge distribution characteristics of PI films during polarization and depolarization processes under different electric field strengths were comparatively studied. The results show that: without irradiation, high electric fields cause a large number of counter-polarity charges to accumulate at the electrode interfaces; after introducing X-ray irradiation, a significant radiation-induced conduction effect is generated inside the material, and the net charge in the specimen decreases. Under the synergistic action of 75 kV/mm high field and irradiation, positive charges are widely distributed in the bulk, while negative charges accumulate extensively near the anode. During the depolarization process, the new traps introduced by irradiation cause the peak positions of residual charges to shift, making charge dissipation more difficult. This study reveals the transport and accumulation laws of charge carriers under the combined action of X-rays and strong electric fields, providing experimental basis for the insulation design of special equipment.

X-ray irradiation,space charge,polyimide,in-situ measurement,pulsed electro-acoustic method