We described in the last report that we found we needed two “cleaning “ shots with deuterium to remove boron deposits on the anode and insulator. In our most recent tests, we had dramatic evidence of the critical importance of these shots and of getting rid of the deposits.
In the first deuterium cleaning shot after the decaborane shot, we got a very low fusion yield, only a bit more than 1 mJ or a billion neutrons. This is what we often get for the first cleaning shot—which occurs with a heavy coating of boron. We then did a deuterium-nitrogen mix shot, which cleans the anode while the pure deuterium shot cleans the insulator. Because we were testing a switch repair, we then repeated the deuterium shot and got a pleasant surprise.
Figure 2. LPPFusion’s silver activation counter shows 220 billion neutrons, or about 1/4 of a joule of fusion energy, from cleaning shot 1, March 27 with deuterium fuel. This matches, within 10%, our record fusion yield.
The yield jumped to 220 mJ or 220 billion neutrons—over one hundred times more than the first deuterium shot! This was the highest deuterium yield we have achieved since our all-time record shot back in May 2016 and was only 10% lower fusion yield than that shot.
The improvement in yield shows that with decaborane we must achieve clean electrodes and insulator before we can get fusion with boron. But it also gives us confidence that once we do achieve this—for example with better heating—we can make rapid progress.