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: X-Ray Shield
Date: Oct 15, 08:09 am
Poster: Richard Hull

On Oct 15, 08:09 am, Richard Hull wrote:

> I am in the process of building a new, large chamber as the basis for a number of Fusor experiments. I plan on doing DT-DT fusion in the chamber at some point so shielding will be critical. Are there any objections to having the lead x-ray shield before the neutron shield, if the only thing the neutrons can hit are some organics (sono-tube formers and epoxies) after the lead, is there any difficulty with putting the moderator outside of the lead shield?
>Joshua Resnick

Joshua, all,

I have wrestled with this question myself. I prefer the lead shield first and the moderator outside (away from the fusor). Some might complain about neutron activation of the lead, but these are fast neuts and the lead has a rather low cross section, so it should not be a problem with the small trace amounts of bismuth 210 formed by the few neuts that do interact. Besides, our neutron levels won't probably get that high anyway.

Did you say DT reaction! You are most fortunate to have a source of tritium. It will really boost your yield and reduce the required voltage of your chamber before the onset of fusion.

Tritium is tricky stuff and as long as your careful all should be OK. You should read the LANL tritium handbook. Go to the URL below and print out the booklet.


I hope the above URL prints out OK.

Be safe and good luck.

Richard Hull