New Calibration Confirms FF-1’s High Fusion Yields
Tests in early June have confirmed that FF-1 is producing higher fusion yields than have been achieved with any other DPF at the same peak current.
The new tests were calibrated with LPP’s silver activation detector and our new commercially-purchased bubble detectors, which had been calibrated to within 25% accuracy by the manufacturer, BTI. The bubble detectors are small tubes of a liquid that is above its boiling point at the pressure in the tube. The interaction of neutrons with charged particles in the liquid creates a nucleation seed for a bubble of vapor to form. Counting the bubbles gives an excellent measure of the number of neutrons generated.
In our tests, two calibration shots were taken so far. Since we were only using four capacitors (see switch section below), we did not expect a lot of neutrons and placed the bubble detectors directly on the outside of the vacuum chamber. We then compared the neutrons count derived from the calibrated bubble detector with that derived from our silver activation counter, which was built to the same specifications as a design which had been calibrated by other scientists 20 years ago. The agreement was excellent, well with the 25% accuracy of the bubble detector. (A technical report on the calibration will be sent out shortly.)
We can now confidently use our previous measurements of neutron yields to compare our results with those of other DPF devices. Figure 1 shows two of the best shots from FF-1 (red dots) compared with the best shots for all non-LPP DPFs (blue dots). The FF-1 results are as much as a factor of ten above the other results and show a sharper increase with higher current. The green dot shows LPP results from 1994, which also lie above the main body of results.
We cannot say for sure yet if this improvement in performance is due to our use of the Axial Field Coil or to the small radius of our electrodes or both. Further experiments are needed to determine this.
The calibration also allows us to confidently chart our own progress so far in 2010 (achieved yield). Figure 2 shows the increase of fusion yield from FF-1 so far this year. Each point represents a new “record” for FF-1 yield. The figure shows that we have traveled a bit less than half way to our goal of demonstrating scientific feasibility which would involve a yield of 10,000 to 100,000 joules. If we can continue at the rate of progress of the spring, we should reach our goal by year-end.