Straight Beam Guns, Ion Trap?

[jeyurkon]

Originally Posted by yagosaga

The 17LP4 is well operated with 14,000 Volts anode current. With such a high plate voltage, you should not see any ion burns, even after a longer time interval. My experience with vintage crts is that those with low EHT have strong ion burns and with higher EHT (above 7 KV) have dim or no ion burns. I did test it with a crt with a strong ion burn at 5 KV. When I increased EHT, the ion burn faded away.

- Eckhard

That makes sense. Ions will have a very short range in the phosphor. By running at a higher EHT the electrons will pass through the damaged layer of the phosphor and excite the remaining good portion.

I do have ion burns on CRTs that ran at 11KV though. They are for the most part minor.

John