| Popis: |
Electrical breakdown of thin (60–100 A) titania films under high dc fields in high (10−9 Torr) vacuum is discussed. Titania coatings were applied to Al2O3 insulators, using the same process as in coating of Al2O3 microwave windows to reduce multipactoring. Recorded breakdown voltages and current dependence, along with the appearance of the coatings after testing, suggest the occurrence of a reduction of the titania films to a lower-order semiconducting oxide similar to what would happen in bulk titania. It is therefore evident that such coatings are not feasible on insulators subjected to high tangential dc fields. |
