Lithium vapor injected into fusor with deuterium fusion initiation.

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Lithium trick
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Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Just a thought, I have reason to believe this could enhance a fusion reaction without the regulations of using tritium in such experiments. Any thoughts on subject by those who might know? I think this would be an interesting addition to such an experiment. Home brewed tritium is a possibility, I'm unaware of any such research on this subject using a Fusor. I believe a small vapor sputter of lithium would enhance neutron flux generation.

By the way, I can laser cut anything needed to make a fusor, grids and such and have over thirty years of TIG welding experiance and have built many high vacuum systems for the semi-conductor R and D field. So I can help others in their research. I might need a bit of help on safe construction of power supplies for a fusor. Just thought I'd add my two cents worth.
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Chris Bradley
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Chris Bradley »

The nuclear reaction rates are just waaay too slow in a fusor. There is no serious prospect of seeing fusion products in a fusor undergoing a second reaction, nor that the neutron output is high enough to chance a tritium-producing reaction with lithium. It'll happen, of course, but the probability is almost zero. Bear in mind that the triutium production you are proposing is already happening. A DD reaction ends up with a triton and a proton ~50% of the time, whereas the other half of the time you get a 3He and a neutron. There's no way that 50% of the neutrons from the latter are going to interact with any lithium you put in there, so the first fork of that DD reaction will give you all the tritium you are likely to be able to make use of. A measured 1E6 neutron/s output is thus producing ~1E6 tritons per second also.
Lithium trick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Well it was just a thought, that's why I posted it. Thanks for the reply though. However any idea's on a source of proper grid materials, tungsten in a thin sheet form seems unlikely to be available, Stainless steel is cheap, thallium most likely very expensive, How about Ni/crome alloy? Commonly used in heating elements such as toasters and blow dryers. I had a source for salvaged high vacuum pumps, but the source went out of business. As far as shielding the fusor, not a problem as we all know, however could one direct a portion of the neutrons via a wave guide as a generator source? It seems this would be useful commercially. The H3 conversion seems to be a good source for medical isotope production, or other app's.
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by gamempire »

Hi Rick,

The Li6 discussion has come up quite a bit during my ongoing efforts. Rather then a vapor though, maybe think about a solid target with a Lithium thin film on it? Its much easier to hit a solid target then it is to hit another ion at the focal point of the grid

I'll shoot you an email to discuss it a bit further, and I might even bug you for some help making a grid to hold a solid target...because the guys in the machine shop at GWU aren't that great at welding =P
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Here's another thought on neutrons. Take a convex metal mirror blank and have it vapor coated with Beryllium. Then take a source of alpha particles, say like a sample of Americium 241 and use the source to bombard the targeted mirror with the alpha particles, the stand off distance should be less then 39 mm, as alpha particles don't travel far. Neutron generator possibly? It should work. Any thoughts? Or use a research reactor to irradiate some Bismuth, this would convert the Bismuth into Polonium 210. I suggest this as just a thought, I know where several such reactors are locally. Oh, it's the stuff that dreams are made I know, but if I can think it up, so can someone else too.

Just a thought...
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Chris Bradley
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Chris Bradley »

For what purpose? I don't see how you would raise enough neutrons even for some activation experiments, with this setup (I could be wrong, but how much Americium can you get? How thick will the Beryllium be?).

I do like your idea of having some sort of directional wave guide for neutrons, in your last post. I like it, because if it could be done then there will be a Nobel prize in there somewhere, I expect. Let me know your plans (then I will claim the idea for myself!)
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Neutron sources are used for lots of things commercially, airport security scanners, medical isotope activation for short lived isotopes, Lots of local hospitals use and need such isotopes often on short notice and shipping is a real problem as you can imagine. There is a company in Germany that uses deuterium gas in a Fusor for an airport security scanner. So yes it can be done. They use gangs of fusors to generate the output they need. The company was a division, believe it or not, owned by Chrysler.

As far as wave guiding neutrons, it was done with the development of the H bomb after WWII.

Read the excellent book called "Dark Sun" by Richard Rhodes, early tests done by Edward Teller, clearly used such techniques for the instrumentation of the devices and I knew a man here locally who personally handled the Liquid deuterium at Enewetok Atoll in the South Pacific.He told me when they set this device off, their ship was over thirty miles away, that's well over the horizon, and they could n't even see the Atoll, and the flash was just astounding. The back reflection of the blast off the atmoshere was beyond their expectations. Just about any radiation I can think of can be wave guided. All the way from the infrared end of the spectrum though microwaves to visible, up to x rays and gamma rays. Of course the wave guides went up with the devices. The first test shot device weighed in at 60 tons, so it was not a practicle device for military purposes.
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

www.NSDFusion.com,

German made commercial neutron generators. Check out site
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

nsdfusion.com

A linear fusor, not spherical grid design. D-T measured out put was done at 14 MeV! at 90 Kv. Now that has my attention. Lot's of good stuff at this site. You should check it out. This is a good site for all to check out here.
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Chris Bradley
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Chris Bradley »

I think we're well aware of NSD here. It gets an occasional mention on the forum. I think you'll find it is 'cylindrical' rather than linear, and benefits over DD fusors here by using DT. It's mainly used for dropping down wells to check out geological morphology.

I'm still not sure I understand what you are saying/topic you are raising. Fusion neutrons are always emitted [almost, as makes no difference] isotropically.
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Carl Willis »

Hi Rick,

You can make significant numbers of neutrons with common alpha sources and pieces of beryllium, and you can do activation, inelastic scattering, and other experiments with those neutrons. My AmBe source is mentioned here (although certain details are purposefully concealed to help prevent little problems for me).

http://carlwillis.wordpress.com/2008/07 ... on-source/

A couple other people on this forum have similar things. They are rarely discussed in full detail. The alpha emitter can be Po-210 from antistatic brushes as well. A healthy amateur AmBe source can produce a few thousand neutrons per second.

>the stand off distance should be less then 39 mm

Much less (unless done under vacuum). The yield of Be-9(a,n) is strongly dependent on energy. You want the alpha particles to arrive in the beryllium with the maximum possible energy, and that means effectively no air attenuation is tolerable.

-Carl
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Lithium trick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Carl,

Thanks for the info about your website, a well done site it is. I knew about the vacuum, but I don't want to give out too much info for the same reasons you did not say more about your device. I consider any info we can share here or else where to be purely a topic of interest and of scientific interest at that. As a laser engineer and applications specialist, I am always interested in the applications end of physics. I get to laser cut all kinds of things people tell me one cannot cut, like 2.5 inch think glass filled concrete, granite, and I have never found a material that cannot be laser cut save for soda glass, and automotive safety glass. That is not saying I would cut alloys that are hazardous, such as beryllium alloys, Brass I don't like because of the zinc and zinc plated steels, and some types of plastics as they are not healthy for humans to be around when vaporized. Copper is a tough one to cut.

I always check the MSDS on all material safety for the process. In some cases water jets are the safest tool for the job. In others a conventional hard tool such as a milling machine.
I would like to assist others with their efforts to make suitable grids for their home made fusor's, as some day I would like to build one of my own. Laser cut grids are the answer for an accurate and durable and reproducible grid. The people at NSD Fusion do have what appears to be a very respectable and durable Fusor design. All are welcome to share.

Any idea's on a wave guided neutron design, Teller did it, so it is possible, proper shielding and neutron transparent and reflective materials would be my guess of where to start.

Good day sir!
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by gamempire »

Rick,

I agree that laser cut grids are the way to go. I've attached a picture of the first grid I made last April.
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Stainless steel? What about using more segments in the design as well.

One should check out Unitednuclear.com

Uranium Ore samples, and Receiver tubes for home made Xray machines, and other cool stuff. Lithium, and Beryllium sources.

Got to run...
Lithium trick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Josh, how did it work for you? Do you have any recommendations on the diameters of these grid pieces. As you know they can easily be made to about any size needed, What about the inner grid? And what material did you use?

I can get time in a shop to make many of these, and TIG weld them up as well. How about the electrical hook ups? Maybe even electro polish and passivate them. I have a pretty good idea on how to do this, But it's nice to see what worked and what can be improved on. I can get vacuum fittings easy enough.

Richard Hull should know this stuff, Any ideas Richard?

Rick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by gamempire »

For the grid in the picture, I used 316 stainless, .055" thick. I cut 3 rings with notches in them. I've attached a drawing I did for inclusion in a report.

The only way I've managed to make an electrical connection is welding a piece of SS rod (1/8" works) to one of the joins on the electrode. I then made a barrel connector with 2 set screws, one connects to the rod on the HV feedthrough, the other to the rod coming off the electrode. I'll try and take some pictures of it tomorrow if I have time.

I actually would like to figure out a way to modify the grid to old a small disc to use as a target. Maybe you can work some wizardry for that (I can provide the Autocad files for the current grid).

Richard did some research on different types of electrodes, I remember reading about the Tungsten tip electrode on the forum somewhere. Even if you made a grid out of tungsten wire, I don't think it would be such a great choice. Even though it can withstand a ton of heat, the resistivity of it the metal makes it a very unfavorable when you have alot of power going through it (try putting 500 or 1000 watts through a tungsten filament from a lightbulb, or some tungsten wire the same size as other wire used in grids, and you'll see what I mean).

Also, you probably don't need to electropolish it even when cut on the laser cutter. Any rough edges were sanded down, and after about an hour in a helium plasma, the grid completely stopped arcing from any microscopic edges.
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

I can easily create such DXF files and in fact I have stated to do so even before your reply posting. I will add in the slots simply to make assembly a snap, literally. With a few tack welds it would be done. Tungsten is durable, but due to it's lack of ductility and brittleness and resistance electrically, it has some issues that make it a poor choice for such work. I use nitrogen as the assist gas to laser cut the stainless steel, so the edges will be clean.

I have lots of options on the electrode hook ups, the one issue to be resolved is the insulation between the incoming electrode wire and the chamber walls. I suggest a Aluminum Oxide ceramic tube of the right size ID and OD to fit into a vacuum fitting, such as an ultra torr fitting made by a company who specializes in such vacuum fittings, Cajon, and/or a Parker vacuum fitting product come to mind. View ports are available from the same companies suitable for vacuum applications. What is the operating pressure so as to select the pump? I assume some where around 10 to 40 microns of pressure? A Diffusion pump along with a mechanical 2 stage roughing pump might be over kill, but? Home made Deuterium made from heavy water and seems possible enough via electrolysis of D2O and a dissicant to dry it. With my practical applications experience in building such vacuum systems, it would be easy for me at least to build such a chamber, complete with vacuum instrumentation and vacuum pump controllers. Neutron detection components would have to be sought out, but all are possible given enough time and money and scrounging around, it could and can be done, obviously.

Any input from others would be appreciated. I assume your idea of a solid core target could be a lithium source? It does seem to be an interesting idea. Of course lithium is a hazardous metal to work with as you know. Other then that I have no clue as to what your solid target could be, or the end goal of such development. More details please, perhaps a DXF file of your flat work on the grid would be useful, the three d model is useful conceptually, but a flat work DXF file is what I need to laser cut such grids. My laser posting software requires such a file format to generate the CNC files for the machine tool and would save me some time as well.

Rick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Josh here is my copy of a bit map file of the flat patterns I worked up. I have created them in DXF format for my laser programming software, minus dimensions as they are not needed to program the parts. I am not going to use a cutter compensation as it won't be needed. The beam when focused is only .008" in diameter, so this will cut the geometry will split the tool diameter in half. This way I'll have the little bit wiggle room afforded for assembly, and tack weld the pieces together by way of TIG welding.

Any thoughts on a inner grid design and I can work out the rest, as well as the target within the inner grid. I assume this target will not be electrically charged. Simply in the focus of poissan (sp?).

I attempted to send a copy of the BMP file I have but for some reason it wouldn't show on the website.

Rick.
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by David D Speck MD »

Josh,

I think that the resistivity of the tungsten wire would not be a significant factor in fusor design. You may be pumping 500 watts into the fusor, but it is being delivered as 33 mA at 15,000 volts or so.

Resistive power losses are measured as I Squared R. That's why long distance power transmission is done at high voltages. Only the current carried, and the resistance of the wire matter in power loss (at least till you get into corona losses!). Jacking the voltage lets you deliver more power without increasing the I^2 R losses.

Even if your tungsten grid element had a resistance of 100 ohms from one end to the other (a pretty high estimate for a decently thick piece of tungsten wire strong enough to be self-supporting), the resistive power loss in the grid element (assuming all the current passed through a single grid conductor) would be only (0.033^2) * 100, or 0.1089 watts, an insignificant loss. In reality, the loss would be even less, as most grid assemblies are a continuous loop, and most grids have at least 3 loops, which would cut the resistance by a factor of 6.

Therefore, you could make your grid out of nearly any conductor. As I understand it, the major deciding factors are the ability of the grid to resist sputtering, and the effects of heating, softening, deformation, and melting due to electron bombardment. I thought I read once that aluminum was the metal most resistant to sputtering, but it certainly would have problems due to its low melting point. I have some tantalum wire put away for my "someday" fusor. Stainless steel is cheap and readily available, but I would think that tungsten might be better if you can find some surplus material that isn't too expensive.

Another issue is how you would be able to clean off the sputtering residue from the inside of your chamber, or from the windows. With some metals, you can just drop your windows into some hot acid to get them transparent again. If you get into exotic grid materials, it may be difficult to find an acid that will dissolve them effectively without attacking the windows.

Dave
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by gamempire »

Dave,

As my mind has been completely elsewhere the last couple weeks, I completely forgot to mention the sputtering issues. I thank you for doing so. Tungsten would definitely cause some severe sputtering issues. The only way we'll find better material for the electrodes is by experimenting though.

-Josh
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by gamempire »

Attached is the DWG file for the design I posted.
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Lithium trick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Dave, We have not talked before, here on this forum, but here's a thought, a sacrifice disk/ cover glass, can be placed in front of the real window to take the sputtering contamination beating from burning in a grid. A simple solution as it's done very often for expensive laser lenses used in Laser cutting, they typically run around 15 bucks or so each in orders of 10 or more, and are made out of KaCl, as a expert in CO2 laser cutting I have seen them used many times commercially, saving my customers thousands of dollars a year as beginning operators during training tend to destroy the focus lens during their training months. I don't use them and have never needed to do so as I have 15 years of cutting behind me, so my training days are well behind me. I don't trash optics at all.

Many good acids will clean out a chamber as you pointed out. My thinking is though a inner grid would be worth exploring as it would collect the majority of contamination by way of electron flow to the inner grid. Would this not be true? Of course these devices do need a burn in period understandably to clean up the chamber and grids.

Rick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by David D Speck MD »

Rick,

Thanks for the info. I had no idea that you could get optically clear KCl discs in that size so inexpensively. Any suggestions as to a source? Perhaps we could arrange a group buy to get past minimum quantity requirements.

I though I would just use discs of flat window glass, or Pyrex, if the ordinary glass shattered. I could probably turn off the system pretty fast if I saw a failure of the sacrificial window. Not sure where I'd find Pyrex discs, though.

Any reason to think that the KCl would have a significant advantage over Pyrex, especially since we're only using them as viewports, not as high power IR laser transmission windows?

Dave
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Dave, Here's a tip.
lenssavers.com The company is International Crystal Laboratories. You can look on their web site for the lens saver product. They tend to be hydroscopic, so one must keep them dry, but the system would be under vacuum, by simply closing a valve at the vacuum pump to hold the vacuum while not running the system. Why waste time out gassing the system again unless you are doing internal maintenance? Pyrex blanks could be sourced from Edmonds optical, but I will warn you they are not a source I recommend as everything they sell is expensive as heck.

I, myself, would look around on the web for vacuum fitting companies, and in particular ask about view port windows, and shield windows for this application. I chose ICL simply as a cheap throw away heat tolerant window that I knew could be made to work. Many other options should work as well. No plastic though for obvious reasons. I would suggest a local scientific glass shop Weiss Scientific Glass in Portland, OR. Or Hayward Quartz in Hayward CA, both companies work with Quartz glass, and they can make these windows however I have no idea what they would cost. The whole deal depends or the size of your view port. So those are just a few idea's for suppliers. Certainly there are many options here. No need to waste a good view port window because of some contamination.

I'm still interested in the dual grid setup as originally designed, I have specific reasons for this choice.

Rick
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Re: Lithium vapor injected into fusor with deuterium fusion initiation.

Post by Lithium trick »

Josh, I have downloaded a DWG reader.

I have also worked up my copy's of the Auto CAD file you posted and I have the math all worked out, I plan on cutting them out this week if I can get the machine time. It's just a couple of minutes on the machine, I'll cut one set, and check out the assembly. Then cut several sets just to have them around, I can get double insulated high voltage wire I use for laser repair, and the PFA tubing I use to triple insulate this wire, it's proven beyond 70,000 volts at WAY BEYOND the currant draw I could ever put through it. So the next step is the biggest hurdle, the vacuum system, by far this will be the biggest part and expense so far and the instrumentation to run it, and hold a set point A good set of idea on the grids I have posted already, it seems to me a long term issue for system performance and stability. The sputtering issues do concern me, I hope you find it useful. How well do the stainless steel ones work for you, and when do you start to see the sputtering problem show up at what voltage and what amperes? You indicated you had to burn out the cavity and grids for about three hours with helium, how is it now?

Rick
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