100-KILOVOLT CERAMIC METAL THYRATRON.
Quarterly progress rept. no. 8, 15 Jul-14 Oct 65,
ITT ELECTRON TUBE DIV EASTON PA
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Tests of seven tubes made with three and four gaps, featuring the iterative planar design previously described, show that operation at 100 KV, 600 pps, can be achieved regardless of the number of gaps. Performance becomes marginal at 100 KV, 900 pps, near the maximum power level. It is concluded that the specified P sub b-rating of 20 X 10 to the 9th power is too high for the anode size presently used. As the performance of multi-grid tubes is largely determined by the anode gap, attempts were made to reduce anode deterioration and thus improve conditions in the gap. This was done with gradient grids featuring slots instead of holes, and by using tungsten for the anode plate. Investigation of the gaps revealed that their voltage breakdown characteristics are related to and reflect the voltage levels to which each gap is exposed during commutation. In a three gap tube, typical hold-off capabilities are thus 30 KV for the control grid gap, near 50 KV for the middle gap, and more than 50 KV for the anode gap. External voltage breakdown through the ceramic extensions of the envelope can be corrected by increasing the thickness of the material and proper design of the gradient grid connections. Author
- Electrical and Electronic Equipment