Looking at Farnsworth's plans for the first time, Craig and his father both had the same thought: Now there's a science project.
They set to work. They found a neutron detector in an Idaho Falls scrap metal yard. Craig built a neutron modulator (which slows down the emitted neutrons so they can be detected) out of a few hundred spare CDs. They found a broken turbo molecular pump lying forgotten at Deseret Industries.
Too poor to buy pricey deuterium gas, Craig bought a container of deuterium oxide, or heavy water, for 20 bucks and came up with a way to make it a gas and get rid of the accompanying oxygen by passing it over heated magnesium filings.
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About 30 such devices exist around the country, owned by such entities as Los Alamos National Laboratories, NASA and universities. ("I bet I'm the only high school student that has one," Craig Wallace said.)