Fig. 1. Radiation device for sterilization of the packing box surface

Fig. 2. Main part of electron curtain accelerator

Fig. 3. Envelope of electron beam computed by E-gun code

Fig. 4. Electric field distribution of the cathode surface

Fig. 5. Arcing point on the ceramic surface

Fig. 6. Electric field distribution in gap between flange and ceramic body

Fig. 7. Electric field distribution after the structure optimization

Fig. 8. Curve graph of discharge trend before and after structure optimization

Fig. 9. Picture of irradiation film discoloration

Fig. 10. Curve graph of energy stabilization

Fig. 11. Curve graph of beam current stabilization