Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Fusion detection
Date: Dec 27, 11:28 pm
Poster: Tom Ligon

On Dec 27, 11:28 pm, Tom Ligon wrote:

>P.S. I have tried it! I immediately purcahsed the BC-720 and never looked back.
Yeah, you rascal, you're much better instrumented than WE are for neuts! They did finally let me buy a little 1" disk of BC720, which I have stuck on a lil' 1/2" Hamamatsu BiAlkali PMT. Preliminary work revealed a bitchin' ground loop or some such, and our analog scope was inadequate. We have just obtained a Tektronix lunch box, and I hope to shortly prove the worth of this setup. But the piece of BC720 is SO scrawny, and my lil' fusor is likewise.

>Oh, I would leave the detector outside the chamber. The neuts we are making will no be attenuated one Iota, by the .060 or even 0.10 walls. According to two of my neutron physics texts. 6" of solid steel will stop less than half of the neuts at 2-3mev. The walls will indeed stop 100% of the electrons, deuerons, and other charged particles nicely. I place my detector just on the outside wall with about 1/2" airspace to avoid the wall heat during operation. BF3 tubes are really sensitive to delta temps, that is why I shun them.
This alternative fusion detection scheme which was mentioned to me is based on the fact that only half of the D-D reactions produce neutrons, but the other half produce protons of similar energy, up in the 3 MeV range. These are usually ignored. But I'm now told there is a scintillator which can detect them that can go right in the chamber. The charged particles will stop quickly in the scintillator, whereas only about 1% of neutrons will flash in BC720. Thus, the detector may be 100x more efficient! I hope to look into this further early next year.

This may turn out to be in the reach of amateurs, certainly those with your skills.