Monday, March 21, 2011

Fusion Achieved

Since I have last written, I have done much work on the reactor, including the addition of a new mounting system, based upon an old scroll saw stand, and the completion of the deuterium system. Also, the neutron detection system was completed.

Here is a picture of the full reactor.
The new detection system utilizes a boron-10 lined proportional tube, which can detect thermal neutrons, however, the neutrons from the D+D -> He-3 + n reaction have very high energies, and therefore must have their energy reduced prior to entering the tube. Therefore, the tube is placed inside a HDPE neutron moderator, which reduces neutron energy through elastic collisions with protons inside the moderator. The tube is read by a Ludlum Model-3.

I eventually fired the reactor up and did some trials with the gas system. My data indicates that the reactor does indeed work!


Due to the lack of the increase between tests 2 (background, unmoderated) and 3 (reactor on, unmoderated), it can be known that the tube was not detecting x-rays or EMI from the fusor, and that any recorded count would be due to neutrons.
The following three tests, (4-6, reactor on, moderated) show a large increase over background, indicating that the reactor was indeed producing a measurable neutron flux, and was indeed working!

I entered the reactor, with this simple experiment into the science fair, and I won both the district and regional fairs, and because of this, I will be attending the Intel International Science and Engineering fair in LA!
What's Next?

I am in the process of rebuilding the gas system to allow for lower leak rates, and hence higher deuterium purity, this should allow for substantially higher neutron fluxes. Additionally, I am developing a penning type ion source, which will be added to the reactor and will allow it to operate at lower pressure with greater stability. Also, I may move the reactor to a new, recently acquired chamber with an exceptionally low leak rate, and a water cooling jacket.
And finally, some pictures of the reactor


  1. Nice work! Those neutron counts look promising. How have you ruled out gamma rays adding to your neutron CPMs? Also, where are you getting your deuterium?

  2. The lack of an increase between test 2 and 3 indicates gamma rays and EMI are rejected by the tube. Also, I calibrated it with an Americium source (mainly an alpha emitter, but some metastable isotopes of it emit gamma rays at energies ranging from a few keV to much higher energies).
    I got my D from a guy I know in academia.

  3. I am interested in seeing a more complete writeup!

  4. Beautifull'77! I hope you get to see SteamBoy on your break time!

  5. Are you going to Intel ISEF?? if you are definitely email me so we can hang out. If your not definitely good luck on getting in (I'm sure this project will)!

  6. QuantumG, It reaches around 200F in some places.

  7. Put your documentation somewhere secure in case Big Oil takes you out...

  8. This project is great!
    How long did it take you to get your setup up & running? How much money did you have to invest? (I'm assuming that fabrication cost quite a bit...)

    Best of luck!

  9. Amazing, thats all I can say

  10. i1,
    I got the chamber machined and welded for free, currently, I have spent around $1500 on all my endeavors.
    I have been working on this for around 3 years.

  11. Good job.

    "I got my D from a guy I know in academia."

  12. So, you can do Fusion but you can't blog about the process? People who hack their iPhones blog about it. You owe the public an explanation for why you didn't blog, if this isn't a fraud.

  13. This all looks very well put together. I'm curious (and forgive me if this is in an earlier post, but I did not look) what you are using for shielding, and the exposure rates measured outside the reactor and at the viewing windows.

  14. Good-looking, professional job on a Farnsworth Fusor ( It's unfortunate that no-one has been able to even break even on the energy in/out from this setup.

    Chicks really dig it.. "Hey, you want to come back to my place and check out my fusion reactor?" :-)

  15. @8r13n
    I do blog about the progress.
    I have a number of posts detailing the progress of the Mk. II reactor, the first mention of it being in this post:
    The first post dedicated to the Mk.II reactor alone is here:
    And yet another post on the progress of it here:

    I have two reasons as to why I do not maintain a weekly update, or regular update schedule.

    Firstly, I have an EXTREMELY busy schedule, managing the reactor, school, extracurricular activities, homework, academic challenge, FIRST tech challenge, a social life, etc.

    Secondly, in terms of building a reactor such as this, in comparison to, say hacking an iPhone, events take place on a much longer timescale, often times the simple acquisition of a part will take weeks or months, or construction or progress will be held up on one small, hard to find, or unacceptably expensive item. For these reasons, progress is slow, so I post updates once I have a decent amount of material to include in an update.

  16. @Anon #1
    I measured no increase over background in terms of x-ray radiation with a thin layer of lead placed over the viewport and camera.

    Without the lead on the viewport, the counter "pegs" so I cannot get an accurate measurement. I would estimate it to be ~ 20R/hr without shielding.
    X-Rays do not penetrate the metal components of the reactor.

    As neutron rates are extremely low (estimated 200 neutrons a second TIER), I do not use shielding, and rather rely on the inverse square law. Where I sit, neutron counts are very near background.

    Take the average adjusted CPM for the fusor running, moderator on: 8.36 CPM
    This measurement is taken 7" away from the fusor.
    According to the inverse square law, the adjusted CPM at the loaction where I sit would be .316 CPM. Meaning a background of 1.616 CPM; not much of an increase from the typical background of 1.3 CPM.

    The increase in neutron radiation background on a flight from NY to LA would be greater than from sitting where I sit during

    All in all, the radiation hazard is essentially zero,

  17. @Anon #2
    Thank you! And did I talk to you at NEOSEF? I recall one judge joking about how the reactor is a total chick magnet.

  18. How far is your project from a sustained reaction that produces enrgy ?

  19. Hi Will,
    nice video :)
    I've just made a short film with a fusioneer here in the UK: password 'voltage'

    I'm looking to make another one, and I was wondering if you would be interested in contributing an interview?

    Keep on keepin' on, and drop me an email :D


  20. is this safe? I mean, the doesn't exactly seem like something people should play with in their garage

  21. Treated improperly without simple high voltage procedures,or x-ray safety, this can be a quite dangerous device.

    High voltage safety procedures were used.
    X-rays were shielded at the viewport with lead.
    They do not penetrate the steel shell.

    Neutron radiation at this level is largely a non-hazard. Mainly due to the fact that it is emitted at an extremely low level, and is emitted isotropically, hence it falls off with the square of the distance of from the reactor.

    The reactor produces virtually no nuclear waste (an EXCEEDINGLY small amount of tritium is produced, renderign it a non-hazard). And it uses no radioactive fuel. It cannot melt down. It can be turned off with the flick of a switch and be totally off. It requires no complex cooling systems.

  22. Neutrons. You can't see them, smell, taste, touch or feel them but they can do a lot of damage. Hope the inverse square rule is accurate !

  23. Hey,

    Superb work here. Really impressed with the work you've put together. Do you have an email address I can grab you on? Had a browse around but couldn't locate and would love to ask you a few questions. You can contact me on rgibson(a)farnell(dot)com



  24. All you have left to do is take over the world!

  25. This is amazing. What do you use to protect yourself? And how long did this take to construct? LOL. It's, keeep up the amazing work.