Tightening LLG-TWIN thyratron plate and ground plate

Last month, we found the arcing problem when running the LLG-TWIN excimer amplfier, I put a teflon plate for preventing the sparks. Today the arcing happened again, I am afraid the isolation plate could not really avoid the arcing. With Randy and John's helps, we removed the alumina plate and found the spark traces on plate of thyratron side.

We polished the plate surface and punched a new hole for conbine the plates tightenly. A wire braid was inserted between the plates in order to avoid the arcing.

Finally we fixed the arcing problem, however the output energy was still low and the beam quality was very bad. When I checked the lone tube windows I found there were some dark grains on the window surface. I want to open the chamber to clean them tomorrow.