Yuhang and Yuefan

We tested the galvo for AA system.

We put a mirror after Faraday because there is still gate valve inside the vacuum tube. In this case(see attached figure 1), we could get a stable reflection. As mentioned by yuefan in the last entry, we had a problem of astigmatism in the beginning. We removed the second lens(-50mm lens), and then astigmatism disappeared.

Couldn't lock situation: If we found the light ERROR X or ERROR Y becomes light on(attached figure 2 and 3), it means we have a large offset in X or Y direction. So we couldn't lock loop and center beam.

Could lock situation: We found if error x is within 290mV and error y is within 730mV(attached figure 4 and 5), we could lock loop and center beam. But we found oscillation of around 30Hz or 1Hz after lock(attached figure 6 and 7).

The moment of lock is attached in figure 8.

Next step:

1. Get the real jittering beam and see if we could center beam.

2. Test galvo even with astigmatism.