The image that started it all (Richard Hull's Fusor IV)
Brian's Fusion Story
The image that started it all (Richard Hull's Fusor IV)
The vacuum pump, a CENCO "Hyvac 7," under testing
By July, I had decided on a preliminary design for my first fusor. It was to be made of all stainless steel, and be roughly 4" in diameter. It was necessary to have several ports placed around the fusor to allow for the input of electricity, Deuterium, a viewing port and a port for the vacuum pump. I had decided upon using "Conflat" fittings for these ports, which are a special type of vacuum fitting that use copper gaskets to create a perfect seal. Unfortunately, conflat fittings are somewhat expensive due to their high-precision construction. I pressed onward, getting only what I needed and not buying off of impulse. I snagged a conflat high voltage feedthrough (rated for 25,000 volts) and a vacuum pressure gauge early on, both for incredibly low prices on ebay.
Another problem was going to be the power supply. I had no prior experience with high voltages, and I felt building a fusor power supply was out of the question for a beginner. I had looked into the professional power supplies, like those made by Glassman or Spellman, but their prices were well into the kilobuck range. This issue was going to have to be tackled at a later date.
Some small x-ray transformers, intended for use in a fusor power supply.
Fusion work slowed to a crawl at this point, since I had all the parts, but no machining capability. I had overestimated my own metalworking skills, and finally realized the amount of precision that would have to go into making this thing was something I could not achieve in a short amount of time.
I settled on a 6" spherical fusor, larger than I had originally planned, but easier to work with. My goal was to make my fusor similar to the Hirsch-Meeks device from years ago. It was to use all conflatted fittings, and two huge Conflat ring flanges would be used to bolt the two hemispheres together. The vacuum port was a QF25 o-ring seal flange, and the Deuterium inlet was a Swagelock "tubing to weld systems adaptor."
By January, everything ground to a halt as there were no machine/welding shops that could do the work with the precision I wanted. I had all the parts I needed to complete the vacuum system, but no way to assemble them at this point. I had also spot welded a few inner grids together from some stainless steel wire.
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The Deuterium gas regulator and reservoir, January 2004
By March, I had acquired a 20,000 volt, 50 milliamp Glassman power supply on ebay. It was the exact model I needed, even though the output voltage was a bit low for my tastes. I inquired with the manufacturer about getting an upgrade to 50,000 volts, but that would cost $2500. Not a trivial cost, but doable in about a year or so.
The best breakthrough came with the chamber construction. I had found a local company in Brockton, MA called "Sharon Vacuum Systems." They regularly build vacuum equipment for MIT, NASA and other high profile organizations, as well as individuals. They could build my chamber for a very reasonable price, and with a fast turnaround time.
The finished chamber was beautiful, having a polished chrome appearance to it. It could definitely do the job it was designed to do.
Also acquired during this period was an Eberline PNC-1 Neutron counter. It was old, but in good shape and operational. I sent it off to Ludlum Measurements for a comprehensive calibration, so as to avoid any claims that I had bad instruments.
The fusor chamber arrives from Sharon Vacuum
Now that everything had been acquired, it was time to start assembling the system. I cleared out a small corner of my garage and started placing equipment on the table. I had also done some vacuum testing with the chamber to make sure I really could get it don to a low enough pressure.
Everything went together in a weekend, and all that was left by early June was to drive in a new grounding rod outside my house, to provide for electrical safety. By June 30, 2004, the fusor was ready for its first taste of power. There would be no turning back. I flipped the switch on for the first time at roughly 11am, achieving the first plasma in my fusor. I did some dry run tests with the neutron counter, making sure that the plasma processes did not create spurious counts. Fusion was only a bottle of Deuterium away at this point.
First light on the fusor, 5,000 volts and 25 milliamps
After returning from a 7 week excursion in D.C. and the Appalachian trail, it was time to finish the work I had started. I ordered some Deuterium gas from Advanced Specialty Gases, which arrived at my front door in a few days. I hooked it up to my gas regulator, replacing the nitrogen bottle that had been there for the non-fusion tests. Upon admitting the Deuterium to the chamber, the neutron counter started to register counts, up to 10 or 20 times greater than the background count. This reduced to a total fusion output of 2500 neutrons per second. This was a low emission rate, but it was detectable with my calibrated instruments. I had joined the neutron club and thus became the 14th amateur to be credited with doing fusion in the home laboratory.
Fusion Star-Sept. 2004
As time went on, I started to get better and better fusion results. It wouldn't be long before I reached the limits of my power supply. Better alignment of the inner grid produced a more stable plasma, and thus higher neutron counts.
At this point, word had gotten out that I had actually finished this crazy project. People at school wanted to see demonstrations, so a more portable setup would be required in the future. An article appeared in the school newspaper about my activities, thus adding an even greater level of interest in the project.
The early fusor in the garage
When I realized that I had to make the system portable, I purchased a moderately sized utility cart from a foodservice supply house. Amazingly, everything fit on the cart with only a few minor modifications, making a more compact and attractive setup that could be assembled and dismantled in less than 30 minutes.
It was with this system that I finally maxed out the capabilities of the electrical system. 25,000 neutrons per second was my limit with only a 20,000 volt power supply. The time had come for an upgrade to 50,000 volts. At the time of this writing, the supply is currently in the shop, and should be back by February of 2005. Hopefully, It'll allow me to get into the million neutrons per second range eventually, and do some neutron activation experiments..
The Cart Fusor-Dec. 2004
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Many people ask me how I came across this strange area of amateur science, and I point them back to a single event that occurred in late April of 2003. I was surfing the web, looking at a wonderful web page about a man's personal collection of all the elements of the periodic table (link here). Under a listing for Beryllium, the author had a picture of a beryllium oxide high voltage standoff insulator, and linked to an image that showed one "in use."
The image is at the right side of this page and the caption read: "Want to see [the standoff] in action? Here's a picture of what looks like this exact insulator being used to make a fun little gadget, a tabletop fusion machine. I have it on good authority that this is not like cold fusion, that it really does work to produce fusion."
Fusion on the tabletop? I thought that was impossible. Like so many others, I had been made to believe that fusion could only take place in billion-dollar machines with huge amounts of input energy. Here was a man who had done it "for the price of a set of golf clubs!"
After reading the information at the various links given, I felt that such a project was within my capabilities, even as a high school freshman. My work in amateur rocketry had given me a bit of experience in the machine shop, and I also had some experience with nuclear processes.
By May, I had made my first post to Fusor.net, and had ordered Richard's informational video tapes on the fusor. By that time, I had acquired a 30 year old vacuum pump off of ebay for $75, whose operational condition was unknown at the time.
People around me at the time thought I was talking nonsense, but I pressed onward and started collecting the parts I needed to build a fusor.
