LPPFusion

Leak fixed, fusion experiments to resume

founder @ LPPFusion

Published on Mar 22, 2020

After two months of hard work, LPPFusion’s research team has succeed in repairing leaks and other malfunctions caused by our minor accident Jan 20 and is ready to resume fusion experiments. Research Scientist Syed Hassan and Chief Scientist Eric Lerner are continuing to work at the LPPFusion’s Middlesex NJ laboratory, taking careful precautions against infection, during the coronavirus emergency. Chief Information Officer and Director of Communications Ivy Karamitsos and Systems Administrator Jose Varela are continuing to work from home.

On Friday, March 20, Hassan and Lerner succeed in getting the pressure in the chamber under the critical level of 10 microtorr (14 billionths of atmospheric pressure), reaching to 8 microtorr by the end of the day. While the amount of air leaking into the chamber is about twice as much as it was before the accident, we think the leak is too small to affect performance. What we worry about is allowing too much oxygen in during the few minutes that we are filling the chamber with fuel deuterium. If too much oxygen is present, the high heat of the plasma right after the shot will allow an oxidized layer of beryllium oxide to form on our electrodes. Since beryllium oxide is an electrical insulator, the current in the next shot will vaporize that layer, causing uneven erosion of the electrodes. But with less than 10 microtorr pressure, there will be too little oxygen to even form a single-molecule-thick layer of oxide. Current will flow around the small islands of oxide formed and erosion will not be seriously affected.

The accident uncovered some mechanical instability (wobble) in the seal for our new upper vacuum chamber. We have temporarily stabilized this seal, but are continuing to work on a more permanent redesign. We are also working on improvement to the main seal around the anode. But we’re in good enough shape to start firing FF-2B again. The accompanying graph shows how the leak rose and fell during the two months after our accident, in response to our efforts to fix things. As in any research effort you can see progress is not a straight line, but it does happen!