Fusor Forums

Hello all,

It's been awhile since I upgraded my rig so I've shelved my bell jars and invested in a beautiful stainless chamber. The chamber is all viton, with the two 6" ends being viton-only "knife edges." The chamber is 4.5" inside diameter and 6" long with seven wonderful ports coming out the sides for possible later additions. I've taken the liberty of slapping a butterfly and KF-40 on the butt of this thing to hook up a little air cooled diffusion pump. Another upgrade was from the non-resistive spark plug to a true blue HV feedthrough.

Check out the pictures and the link to the video of it being taken for a short test drive.

http://www.youtube.com/watch?v=FVSY8fnK0do

Enjoy,
RT

Robert,

Nice clean work, and good video too.

Is that a big neutron detector tube on the left hand side of the photo?

Steven

Thanks Steven,

Yes that most certainly is, that's a 22" Reuter-Stokes Aluminum, I've got four B10's as back ups for the He3 as well!

RT

What a beauty!!

I see you also have a Veeco leak detector diff pump. What type of flange did you use to connect the Veeco diff pump to the chamber?

Hope you get lots of neutrons .

Fredrik PG

Robert -

Very nice, indeed! I think you've made some good choices and obviously have the makings of a useful Fusor.

Thanks for the pics.


Dave Cooper

Pretty indeed!

I have noted here that the closer the grid geometry matches the outer chamber shape, the more neutrons I get per watt of input -- so you might just want to try a cylinder grid aligned the same as the tank.

The way this one is set up, you could even fire in ions from a source(s) at the circumference and have that geometry very nice.

You may also get better results (or not) if you put some screen wire over the ends of some of the port entries to make the cylinder more uniform re electric field in there.

Is there an explanation for why the hotter part of the grid is in the same direction as the singular electron beam? Is this usually the case for most fusors?

2:50AM
July 29, 2010
Eastside of Seattle Washington

Neutrons on Fusor V!

Power Supply: 35,000 volt 20mA mains frequency voltage multiplier with water resistor.

Vacuum system: Welch-1400 Belt driven mechanical roughing pump, Veeco air cooled diffusion pump to butterfly valve.

Neutron Detection: 22" Reuter-Stokes He3 proportional counter w/ Ludlum model 12 ratemeter.

Gas system: Platinum electrolysis with NaOH electrolyte run through drierite drying stack into Swagelock metering valve and Swagelock needle valve.

Log 1: 16,500V -- 25mA -- ~15 Microns -- 150 CPM on 22" RS He3 tube 3' from Poissor.

Log 2: 20,350V -- 22mA -- ~14 Microns -- 300 CPM on 22" RS He3 tube 3' from Poissor.

Log 3: 22,000V -- 20mA -- ~12 Microns -- 400 CPM on 22" RS He3 tube 3' from Poissor.

Log 4: 28,600V -- 18mA --~10 Microns -- 500 CPM on 22" RS He3 tube 3' from Poissor.

Log 5: 33,550V -- 5mA -- ~10 Microns -- 1000 CPM on 22" RS He3 tube 3' from Poissor.

Moderator was removed from proportional counter while operating to test for noise. These here be neutrons. I've been blessed with a relatively noise free fusor with little to no x-ray radiation beyond 1 foot. I believe it's time to stick a webcam on this bad boy and give it some more power!

Highest TIER (total isotropic emission rate) for the evening was ~50,000 neutrons/second.

Thank you and enjoy,
Robert Tubbs

http://www.youtube.com/watch?v=PtqRrVTjHCg ------ Video showing the Fusor producing neutrons.

Welcome to the Neutron club Robert! I have added your name to the listing. Nice work. You will do better as you get more accustomed to operation, which is a bit of an artform in itself.

Really nice gear and a fine effort. I have archived this thread of accomplishment.

Richard Hull

Awesome! Congrats and thanks for posting the video it was great to watch.

Robert,

Well done, great effort...

Just on your wording, we usually refer to TIER or Total Isotropic Emission Rate, as one generally uses the term flux for particles travelling through a volume of 1 ccm/s. It is however correct to speak of flux at your 3He tube.

Steven

Congratulations, Robert. This is the reward for a lot of patience, hard work, background research, and the investment of lots of time and money--but also represents a new beginning: now that you have a fusion machine, you have to decide what to do with it next.

Good work and welcome to the Neutron Club.

-Carl

Thank you all, this has been quite an adventure, funny how it's just beginning of the hobby though.

I believe I began eyeing those DD neutrons back in my first year of highschool when I built my first isotopic neutron source which was about 50µCi, I graduated to some 40mCi Americium and small Californium sources but still needed something with a little more juice to perform hard core neutron activation and thus came about the desire for a Fusor.

I greatly appreciate the help and advice that's been given to me over the last 5 years by the forum, I hope I can contribute even a tenth of what has been given to me.

Thanks,

Brian McDermott for being my first contact and getting me started all those years back (and for the wise tip on getting those informational videos from Richard.)

Richard Hull for the Informational DVD's on fusor operation.

Tyler Christensen for helping me on my ever constant power supply troubles (until I finally boycotted high frequency hahaha) and for the loan of the vacuum gauge after mine took a hit from my multiplier and got thoroughly toasted.

Carl Willis for the loan of a model 12 to which I owe as soon as I surf through my couch cushions. And also for greatly aiding in the design of my Silvered Geiger-Muller neutron detector. Oh, I almost forgot, thanks for knocking some sense into me back when I was trying to pump down that sewer coupling and shove 60,000 volts into it, I'd probably still be doing that if it wasn't for Carl.

Also thanks, Ma, Pa, Amy, Jeff, Julia, Kurt and all the other great weirdos and teachers in my life.

P.S. Sorry for the confusion as to the correct vocab the change from flux to TIER has been made. Thanks Steven for correcting that.

RT

Congrats! The video was really informative (I guess a video is worth a thousand pictures!); I wasn't aware you were using pulsed work. (I assume that's what you were doing with the capacitors.)

Anyway, congratulations; that is a beautiful discharge you have in the photo!

-Ben

Also, just a thought. About sticking a webcam near the fusor: I have gone through several (I think three) cheapo webcams to monitor my fusor. I don't pretend to have done much research on why this occurs, but I would assume that they keep breaking because of EMP's. (Unfortunately, that is an area that I know little about.) Granted, I was using a tad more power than you did on your first run, but just wanted to warn you in case you step up the power before you go sticking a $100 Logitech webcam there.

Congrats on your neutrons!
~Ben

Fantastic accomplishment and congratulations on both a great working (Lots, and lots of Neutrons!) and looking system. Excellent detector equipment, too. You need to consider experiments to try in order to boost your neutron count and improve the process – look forward to reading (and seeing) more results.

Thank Ben, Dennis..

As of Friday morning I was pushing about 250,000 neutrons on the fusor, quite a bit more than I thought possible with my silly electrolysis setup but pleasing non the less. I modified my power supply the previous night (which by the way is actually not a pulsed PSU but a homemade mains frequency voltage quadrupler made from 24 microwave oven capacitor's, diode strings and driven by now 5 microwave oven transformers with their secondaries in series) to give me 60,000 volts at over 100mA under fusor load. I pushed the limits of my circuit breakers for 6,000 watts and used brute force to get a TIER of 250,000 n/s.

I would love to see this thing run on some clean D2 cause currently I feel like I'm running a Ferrari on corn oil, the very least I'm going to try and do tonight is add a cold trap in addition to my drying stack to attempt to remove more D2O vapor from the D2.

Here is some more eye candy..

The first picture is of the ludlum with the helium 3 counter 3 feet away reading when I first broke 2,000 CPM @ 3 feet (100,000 n/s TIER.)

The second picture is when I duct taped my camera to the view port to capture the x-rays effect on the camera's CCD during neutron production.

The third is what the fusor looks like when I'm haphazardly shoving 50-60kV in it at 100mA while it vomits out about 250,000 n/s using simple electrolysis. Can't wait for a real cylinder of D2.

RT

Robert,

Thanks for posting...

The 6 Kw heater will come in handy in winter

Steven

Wow. 6000W? I cross-checked this (someone please correct me if I'm wrong), but at 6000 watts, you're pumping the highest energy into your fusor of anyone here (Rosenstiel fusor = ~2KW). I'm going to take a wild guess that when you get your cylinder of D2, your neutron rates are going to go into the millions. I'm guessing you use a tantalum/tungsten grid? (Especially at 100ma)

This looks really exciting. Can't wait to see more results from the gas cylinder.

Ben Bartlett

Hi Robert,

I think you've reached a performance milestone among fusioneers using electrolytic gas supplies. (Even so, I have no doubt that clean cylinder deuterium would work wonders to improve your numbers. If you want a LB-A cylinder with about 500 psi still on the gauge, let me know.)

Did you calibrate your He-3 countrate against something like a BTI? I didn't see this mentioned but maybe I wasn't paying close enough attention.

-Carl

I trust that Jochen will not mind reproducing his diagram under the circumstances.

His website covers this in more detail.

Basically, you should aim to use multiple transformers by employing one side of them as voltage-doubling auto-transformers (and isolate/disregard the other side).

...I have presumed your transformers have an earth [or other] centre tap, but if they don't then you just shouldn't use them for what you are trying to do.


.

Chris, you're not being helpful. Are you even familiar with microwave oven transformers? All the available evidence suggests you're not.

The image you borrowed from Jochen Kronjaeger's site comes from this link (why you can't provide the link I don't know): http://www.kronjaeger.com/hv/hv/src/obit/index.html

That's right, the context there is OIL BURNER TRANSFORMERS. They are a center-tapped transformer. MOTs are not. This method is not applicable. Your condescension with Robert is unwarranted. Provide your link it if is relevant, otherwise get out of the thread. Come to terms with the fact that people will do things that are not UL- or CE-approved. Seems to me the risks are understood and acknowledged and, in Robert's embodiment, are not life-threatening.

Carl

Carl Willis wrote:
> Seems to me the risks are understood and acknowledged and, in Robert's embodiment, are not life-threatening.
This did not at all appear to be the case here, because he seems to think sitting them in an oil bath will fix the risk. It doesn't.

Condescension was not intended. The immediacy of trying to avoid harm was. If I am in error on this, then sobeit. If these MOTs aren't centre earthed then they are not suitable for stacking in any configuration. Period.

>If I am in error on this, then sobeit.

No, not "sobeit." The error wasn't a minor factual mistake that will slide by; we all make those from time to time. The error is your belief, still in evidence after you've been shown to be off-base, that you know what someone else (e.g. Robert) is doing better than he does.

>If these MOTs aren't centre earthed then they are not suitable for staking. Period.

I'm going to call your bluff. Go ahead and explain your background and experience having to do with the other MOTs (other than "these") that aren't centre earthed.

>If these MOTs aren't centre earthed then they are not suitable for staking. Period.

Thousands upon thousands of hobbyists worldwide have used MOTs in all manner conventional and unconventional. Primaries get rewound, shunts get knocked out, oil insulation gets added. Transformers get stacked and paralleled in myriad different configurations to meet users' needs. There are decades of experience with this transformer type in the Tesla coiling community. With that extensive history in mind, tell us about what you have specifically done and what you know about them that calls into question Robert's use. Do it now.

-Carl

Carl Willis wrote:
>Chris Bradley>If I am in error on this, then sobeit.
> No, not "sobeit." The error wasn't a minor factual mistake that will slide by

If you cannot see a way to 'let this slide by' then, on your initiative, let's do this: I see nothing I stated that is incorrect. Please restate the sentence that contains errors and then we can examine any errors you consider I have made in an objective manner.

The error I may have made [for which I said 'sobeit'] is to have bothered trying to be concerned. I see no factual errors. If there are, please repeat the sentence/paragraph that contains these errors.

I'll help you a little. I have [aimed to have] said;
1) Putting secondaries in series will cause a potential between the windings.
2) The potential exists from a secondary at one end of the stack, across to the primary, through the mains, back into the primary at the other end, and across to that secondary.
3) The potential of 5 transformers in series is in excess of the voltage you'd expect those transformers to be designed to tolerate between windings. (They will, of course, be designed to tolerate higher voltages for a short period of time but cannot be relied on to do so.)

Not sure I have said anything else without conditionalities like 'I think' or 'I am not convinced by'... so, what is in error, 1, 2, 3 or something else I didn't notice I had stated?