Basement Fusion Reactor

Do you ever wonder what projects your neighbors have going on in their basements? [Will Jack’s] neighbors might be surprised to find he’s building a fusion reactor. The first step toward completing a Farsworth-Hirsch Fusor is up and running. The picture above shows heated plasma contained in a magnetic field. Next he just needs to up the voltage and inject some deuterium.

Yeah right! Deuterium, aka heavy water, is extremely rare and very difficult to refine. If you’re not familiar with the substance, you should get your hands on the NOVA episode: Hitler’s Sunken Secrets.

We’re glad to see that [Will Jack] is donning a lead vest for protections.  [Will O’Brien] cautioned us about the stray X-rays these things produce when he covered fusors back in 2007.

103 thoughts on “Basement Fusion Reactor

  1. WooHoo My first hackaday comment!

    I am in a club here at the University of South Florida called X-Labs, and we have a small IEC Fusor. We use it for demos, but hopefully it will fuse some day. The Fusion reaction is not dangerous at these voltages at all. I am 15 years old and I have built power supplies for the thing. I love seeing one in a glass bell jar. The plasma is so much more viewable, it makes me want to use a bell jar. Great post and great design; i love seeing more people do hacks like this!

    @Will Jack, you could try using a Biphase Doubler rectifier for your neon sign transformer, this should give you almost the full -15kv instead of your -9.5kv. The problem with neon sign transformers is that their secondaries are center tapped to the case, so they become hard to fully rectify.

  2. If anyone is interested in fusion devices, have a quick search on “polywell”. Basically the device is based loosely on the electrostatic fusor concept, but it actually uses magnetic confinement. The advantage of the polywell is that you won’t get losses associated with grid heating, as you do with the fusor. The polywell was developed by Bussard, who sadly passed away a couple of years ago.

    Bussard did a presentation at google, you can watch it here:

    A transcript of the presentation is available here:

  3. lol, stu sez “i be ignant”

    coyt, you’re 15? you’re in a club at UofSF? wow, lots of respect for you, but… you know you’re gonna be a virgin for like… ever, right? well maybe not, cuz skolnick and the gang did all right, but still…

  4. Coyt and Will Jack – Even though people like stu are voting democrat and busy enslaving us with Government regulations… You are both ahead of the curve, don’t let naysayers get in your way.

    Keep up the excellent work!

  5. @ Lee:
    NO tritium for amateurs (USofA)—besides being expensive, getting it requires all kinds of forms filled-out for the gov’t. It is a massive no-no to have it or experiment with it without the training that the gov’t requires. Tritium would be a danger to you and your neighborhood.

  6. Stu said: “Its clearly non govt-authorised, totally unregulated, possibly under-shielded. Simple.”
    The gov’t doesn’t restrict this type of experimenting—it is, indeed, totally unregulated. Simple.

  7. Journal of M. McFly

    Doc Brown and I just got back from 2015 where I was totally surprised to learn that Will Jack made the 2014 Darwin Awards. He was named right above the guy who tried to improve the thermodynamic efficiencies in his apartment furnace with the unfortunate side-effect of burning down the whole complex.

    But, all of you should be pleased to know that Doc and I tried to change the time-line so that Will would live, (we made him more concerned with making his mortgage payments) but Will got iced by terrorists when the poor guy tried to sell them some “Helium 3” he was calling Tritium. I guess those Libyan terrorists knew their isotopes.

    Oh well. Back to the Future for us. I hear you can mod your Mr. Fusion to triple the amount of energy it produces per unit time. There’s a slight possibility of it exploding but I’ll put a couple of layers of lead tape around it. Should take care of any mishaps.

    But if an exploding, falling sky-DeLorean (TM) happens to knock you dead, well, as long as I get to research what I want, where it’s convenient to me, it’s OK.

    Then again, there might be a reason why test-facilities exist… maybe they limit the damage to others when things (radiation, fire) go unexpectedly wrong.

    M. McFly

  8. Deuterium’s actually pretty dang easy to get your hands on. Here’s the easiest source I know of:

    $10 for 10 grams of heavy water. Separate the deuterium using electrolysis, just like you probably did in high school chemistry with the regular hydrogen in water.

    Tritium’s not totally unobtainable, either. I have a bit here on my desk, in the form of a sealed glass tube with a phosphor coating. You can get much bigger ones from self-luminous exit signs, but I really wouldn’t suggest messing with that unless you know what you’re doing.

  9. I’m sure I’m not the first person to mention this, but heavy water is actually naturally occurring, just in small concentrations. It’s also deuterium oxide, not just deuterium. But whatever. A fusion reactor would be sweet. =D

  10. Heh, I am collecting parts to build this thing. Got some strange looks at the garden centre when asking if they had any bell jars for “a vacuum chamber”… lol..

    Yeah, X-rays are dangerous but if you are careful and use safety precautions such as leaded glass and shielding (lead rolls from spare roofing stock work) and dosimeter schedule to determine safe levels you should be fine.
    Also its quite feasible to use low pressure helium to make up for a lousy vacuum (increases electron free path) and makes the whole system a bit safer while still demonstrating many of the effects of a fusor.

    On a side note, if you are feeling creative its quite simple to make a hybrid magnetic fusor using surplus toroidal magnets (or arrays of square magnets from Ebay etc arranged in a funnel shape) to get substantially more ion focussing with moderate high voltage.
    maybe combine the two and use outer basketball shaped grid, intermediate magnetic array and centre electrode.

    another amusing idea is to homogenise the fields by spinning the magnetic cones (have no idea if this would work) and applying field feedback with external magnets to iron out any kinks in the fields to stop those irritating leaks.

    (shades of “The Time Machine” here…)

    contact me on the high voltage and electronics forums..

  11. I don’t know if this has been said already (can’t be bothered reading all the comments) but Deuterium is a non-radioactive isotope of Hydrogen and costs about $150 a bottle from gas suppliers near me… It doesn’t require any licensing or anything to get. Tritium is radioactive and thus a controlled substance, but Deuterium is dead easy to get hold of.

    And for uninformed people like Stu, the radioactive aspects of this are not remotely dangerous – the biggest danger for this guy is that he is doing it in a glass bell-jar, which could have a big risk of shattering at the low pressures required for fusion. Usually fusors are made with metal vacuum parts.

    Then there’s the electrical risk – although they use extremely low current (a few milliamps), fusors generally operate at around -10kV to -40kV (the inner ring is at a negative potential relative to the grid, which is ground).

    All you have to worry about apart from that is a few fast moving neutrons, but home built fusors are so inefficient (compared to, say, industrial ones that are actually used as sources for fast neutron radiation) that you’d have to sit less than a metre away from it while it was operating for a few weeks or months to do any real cell damage…

  12. As far as stresses on the vacuum chamber go, high vacuum is pretty much equivalent to low vacuum. Say the pressure is 1/50 of atmospheric. That’s a pretty crappy vacuum in the physics world, only useful for chemists doing vacuum distillation. However, at that pressure, the stress on the vacuum chamber is 49/50 of what it would be if it (didn’t) contain a perfect vacuum.

  13. Give Stu a break, he’s British. No seriously, I’m pretty sure he’s a Brit because of that extra “u” in “neighborhood”, and Britain is called “the Nanny State” for a reason. Perhaps he’s a member of Parliament.

    I figure if we’re gonna get on the nutjobs, AND we’re gonna make it political, then we need to make it cross borders as

    Will Jack, excellent work.

  14. One thing you could do with this design to get some better efficiency would be to make the outer electrode a larger copy of the inner one. Having two different electrode patterns prevents the fusor from operating in ‘star mode’ where the ions that collide with the grids are preferentially removed and the ones remaining are on trajectories that pass through the spaces in the grid. The grid collision losses are one of the big barriers to efficient operation, and anything that can be done to reduce them results in big gains. That’s the (very simplified explanation warning) theory behind the polywell modification as well. Magnets to trap electrons, in order to create virtual electrodes rather than ones requiring wire, so that grid collision losses don’t occur.

    In another vein, if you ever do get a decent neutron flux, lining your chamber (metal chamber only for this) with lithium will result, if I recall correctly, in neutron activation of the lithium to tritium. Basically this would be the breeder reactor configuration. Start it on deuterium, make enough neutrons to start breeding tritium, and then continue to fuse the tritium for more power.


  15. i don’t see any problem with this deuterium fluorescent light, but if i believed for a second that my neighbor was creating a powerful neutron source – and actually able to do it, i would be more than just concerned.
    so why the hostility against stu?

  16. @ tantris

    Because he’s making it clear that he has no idea what the project’s actual dangers are or are not, and is promoting a climate of hostility against hackers and basement research.

    A similar example: not that long ago, police busted a nearby amateur soapmaker, because her neighbors had noticed that she was buying chemicals and had lab supplies. While eventually charges were dropped, it took her a lot of money and a lot of time, she has a police record, her neighbors still treat her as a pariah, she never did get her chemicals and equipment back, and the judge gave her a statement basically saying that the whole thing was her fault, and that no one outside research institutions should have chemicals, make their own products, or do their own research, and that the police and neighbors were entirely right to treat her like a scary person. What a slap in the face to someone who’s doing a process that’s been known and done at home for thousands of years. What a slap in the face to everyone who actually makes things, does things, and thinks.

    When I see someone promoting this sort of bullshit, my blood boils, and I can tell that a lot of the other actual hackers on this board have a similar reaction. Guys like stu can go to hell.


  17. @polossatik @khordas: yes, yes, yes
    and i can’t tell you how much i hate this anti-science paranoia. but i don’t think a project that -if it ever worked- would (slightly) irradiate your neighbor’s kids, is the project to cry freedom-to-hack over.

  18. You feed the inspiration of life. You ruin the dreams of many. What political world are you in? This is no longer a time of the “government” ruling the world. You think Communist China is entirely as powerful? They may cover things up but the media captures it all. Soon enough the people will overtake what needs to be overtaken. I won’t speak for many but I can tell you that many of those scientist that flocked to America… did for one reason. Freedom of experiments. They are going to do what they want to do. Try and stop them and you may just have another Hitler Nazi regime coming after you with some way more powerful weapons than firepower… we are talking massive amounts of RadioActive WaveGuns that can instantly fry all brain cells… you are still alive but awfully retarded. Wait, I think my last WRT54G did that to you with 251mW power! LMFAO.

  19. @ Tantris,Please read some of the comments before you do, this device currently does NOT produce x-ray or ionizing radiation at the moment. However, when i convert it to a full fusing fusor,it will not output very many neutrons at all (as the farnsworth-hirch type fusor is inherently inefficient) , and those are easily shielded by borax in water, the x-rays that will be produced will be shielded as well. I am not placing myself or others in danger of being irradiated. The greatest danger of this project is electrocution, which I am protected against as well.

  20. Am i the only one who thinks this thing should be placed inside a bender-bot in honor of farnsworth :D

    Maybe it can be used to give the bender-brew still some nice glowing eyes!!

    In all seriousness, I made about ten of these one year(very little, cost me like 300$ total, all new supplies :p) and noone ever complained… and i hung them on my fething deck.

    Not to diminish from his work AT ALL, this is a remarkable project, but I really want people… to understad that unless he ups the voltage ten, increases the vaccum, AND starts injecting deuterium w/ tritium, we, and the neigbours cat, have nothing to worry about.

  21. Stu is the same kind of wonko-nuts who think CO2 is causing global warming.

    We have cosmic rays that are constantly bombarding everything and they can travel through the earth.

    There are more dangerous contaminates in the average home then you will ever get from a few neutrons that can only travel a limited distance.

    Stay away from cathode ray tubes Stu, the xray poltergeists might drag you in.

  22. cool lamp, on the scientific level though I must say you know in order for the proper reaction to take place pressures and temps are not up to specs, but like I said cool lamp, will for sure get you laid!

  23. @ Stu, PopularScience Mag gave a 50k scholarship to a high school kid a few yrs ago for building a fusor, currently there are about 65 of these fusors running in the 48 states, IIRC 7 of them built by high school kids. Andrew Seltzman is probably the most noted kid, hes now @ Univ of Wisconsin at Madison working under DR Kulcinski.

    These devices are somewhat common, of course there are those of us who are scared of things they dont understand and they tend to panic due to the lack of understanding.

    @ STU, we’re having having a chuckle at your expense, I hope your feelings arent hurt.

  24. hmm..

    wonder if anyone has tried building one of these to collide heavier ions than deuterium.
    Sounds like a good starting point for a “Small Hadron Collider” :)

    (disclaimer. IANAP (I am not a physicist)

    at the moment the main sticking point here is the lack of a good vacuum pump.

  25. This is really interesting to me, im allways trying to find things that are interesting, ive pretty much masterd computers(Gay) and im moveing on to electronics and id love to build one of thease babys

    theres a few things that are ticking over in my brain

    to create 15,000V at , i think i read like 20mA
    How many amps would be drawn from the primary winding? and would it be at 240v??

    How much heat is generated?

    WHat will happen when Deterium in “Injected” into the Core, What kind of reaction will occour??

    im no Physics genius as you can probally see from my questions

    “In another vein, if you ever do get a decent neutron flux, lining your chamber (metal chamber only for this) with lithium will result, if I recall correctly, in neutron activation of the lithium to tritium. Basically this would be the breeder reactor configuration. Start it on deuterium, make enough neutrons to start breeding tritium, and then continue to fuse the tritium for more power. ”

    when u say “and then continue to fuse the tritium for more power”

    do you mean fuseing tritium will result in a higher energy output as Heat???? than deterium

    And anouther idea , are the effects of microwaves or an electron gun known on the plasma???

    chris Ramsay

    P.S Stu if your Denying experiments then you might as well remove yourself from the gene pool.

    Justify your existance!

  26. Chris, I highly recommend you visit the forums at . You will find lots of help there.

    To do measurable fusion, you generally need 20 kv at the least, full wave rectified, at about 5ma minimum.

    The primaries are generally run at 120 volts, use whatever your transformer is rated for. The current draw changes due to the magnetic shunts on the transformer.

    Generally a fusor will draw less pwer than a microwave.

    *ION* guns can be added to increase output, and I do not know the effects of microwaves on one of these.

    I do not have any experience in breeder reactions, however I do know that tritium is fairly dangerous.

  27. Thanks Will * Goes to

    Im greatley interested in this ,,, will have to take a trip back up to Royal derwent, its a abandoned mental hospital dateing back from 1830’s if i remember corectally ,

    theres huge pressure vessels for the hot water boilers so i could make a good chamber out of one :D

  28. some one said that tritium is hard to find but i wear a vile around my neck…in glass coated with phospherus pouder and then a layer of plastic:) lol now i just know sum tard is going to be like ” but dude its radio active” first off i know… secondly i also know its only hamful if inhaild or mixed with water and then injested. also ther are alot..alot of radio active material all around…in your house even. some of its gamma and not betta like whats on my neck. but anyway you can get tritium fairly easy… look up betta markers or betta light..or somthing of that nature… lol sorry spelling wasnt my fave in school. but do check out what im saying and you will see what i liked to learn in school

  29. btw tritium was in all the exit sighns. they started to remove them …because after ther use was up they had to change the tritium tube.. but sumtimes the glass tube would break and poision the air….and tritium is leagle to have in modest amounts… so is uranium…yah… however i cant speac about enriching it though lol. but you should do reserch about the past and the actual laws:)… dont be nieve..or ignorant hell ever heard of uranium glass.. aka petrolium glass. gues what they put in the glass lmao.. try to buy and finde sume its not that hard all

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