Columbus-I Pinch Tube Build

This forum is for other possible methods for fusion such as Sonolumenescense, Cold Fusion, CANR/LENR or accelerator fusion. It should contain all theory, discussions and even construction and URLs related to "other than fusor, fusion".
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Mark Rowley
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

The Project Sherwood book by Bishop is definitely an educational read. Richard, I believe it was you who mentioned it sometime in the mid to earlier 2000's which piqued my interest to the point of getting a copy.
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Re: Columbus-I Pinch Tube Build

Post by Patrick Lindecker »

Thanks Rex and Mark for both links (abstract and 70 Mbytes PDF). It seems interesting and a lot to read.

Patrick
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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

A very wise man, Mark.... A large number of folks, especially newbies just seem to refuse to read up extensively on the history of fusion. The bulk of ideas that tend to bubble up here are just hair-brained the rest have pretty much already been tried and failed. What is the old saying..."if you don't know history, you may be doomed to repeat it".

Certainly, making a fusor is just repeating what has already been done over and over again, but it is a conscious decision to do so, a learning moment and an opening to a much broader, hands-on, experience with fusion. Only a fool would think they are going to push it or use it as anything more than a stepping stone, if they really are interested in moving on beyond its capabilities.

So far, zero-point-zero folks here who have made and operated a Farnsworth fusor have pushed out way beyond the fusor. Some of the younger set may have gone on to college and are "in th' biz" for cash and glory, but still zip in the "fusion for real" biz. Not one watt of electrical generation for real use has taken place. What was once ancient history in the fusion biz is now pretty again, (Stellarator), while the latest wonderments, (NIF), is just another shot in the dark that missed. So far, in the world of useful fusion, we have monster projects spread over many acres of land, all have monster budgets and spending and not one of the folks in the biz who claim they reached over unity has bothered to heat a little bit of water and turn a "tom thumb" generator to light a light bulb. I realize this would be stupid, but then that very act would make me unable to claim 0.0 electrical generation.

The now much storied fission "water boiler" in the 40's generated real electricity, fission electrically powered submarines, a Russian 40 megawatt power station supplied fission electricity to an entire city and a United States fission reactor powered the town of Argo all before 1956 just 11 years after the atomic bomb. Where is fusion? Still lying on its face in the dirt....still trying to get up.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: Columbus-I Pinch Tube Build

Post by Dennis P Brown »

I built a small magnetic "mirror" machine as my senor project in college. It was very instructive but my diagnostics were far too primitive and few to get meaningful results - I simply had a scintillation detector to 'see' back-scattering ions. The key to any such machine are diagnostics so I'd follow the advice of some here on that issue. Neutrons, however, are of little use since the point of any such ion 'trap' is measuring the ability to hold the ions, and neutrons flux will provide little meaningful feed-back on that aspect of your machine.

That all said, the building of your device is, of itself, a worthy goal and I hope you both continue and post your progress.

As for successful fusion (not even talking break-even, here) in any near time-frame, zero chance of that even as billions are wasted on many projects. While the German stellarator is certainly the best current device and very successful for what it is trying to do, it uses no tritium and isn't meant to do any real fusion. If it continues on its excellent path, and achieves its goals, certainly that shows some interesting promise - but as Richard very correctly points out, that is still zero energy.

The Germans would, if they get their final goal and finish successfully, want to build a true proto-type power reactor that would likely (again, if they manage to build it) achieve well above true net power (a 'if' but not a stretch like most all other ideas/approaches.)

However, regardless of that I am deeply concerned about the cost to build, not the physics of their Stellarator. While their current machine cost around a billion dollars, then by the cube law, and considering shielding for the magnet's (meaning far larger still) a real proto-type would likely cost well over over nine billion in today's dollars - so, ten years from now, likely much more.

Then if that worked (that is really getting very questionable speculation now) that would indicate that a real power plant would far exceed that cost. In other words, even if real fusion was achieved, its cost based on currently 'best' physics approach - i.e. the stellarator design - would cost, at a minimum, three to five times the currently hideously expensive fission plants. How does that in any way make economic sense for a giga-watt plant?

Sadly, even if fusion is possible via the only realistic mode anyone has really studied (no, tokamak's are not really useful devices - besides making stellatators look moderately priced, their basic physics is terrible for any power production), fusion energy on earth simply can't be useful in the time frames that it really would be most critical - the next fifty years. So, basically, Richard is spot on even if current progress does (again, if) continue successfully.

For those interested, here is a site for the latest news relative to the German Stellarator:

https://phys.org/news/2018-11-peak-stel ... sults.html

It is very promising but as I said, cost is the only issue that really matters in the real world once one does get past the physics problems. There is no engineering approach that can help so I simply see no viable approach to fusion energy in any realistic time frame that matters to humanity.

With the terrible damage of AGW even now becoming fully apparent (and ignoring its far greater disastrous effects within the next fifty years as the Earth's equatorial regions become impossible for human life without AC) it is tragic that the Candu fission reactor is being completely ignored as a very safe, and extremely low carbon power source.
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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

Candu is a nice system but demands huge amount of heavy water. However this would not be an obstacle if the world got serious about heavy water production.

The reality for any nuclear generational source that proves itself real and viable is cost as Dennis notes. I have harped on the bean counter being the final arbiter in any final scenario.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Dennis,
It would be best to flat-out abandon all hope for any power producing fusion machines in our (or anyone else's) life time on this forum. There's no "sadly" in my book. There's a "it would be nice to have" and I feel most of the old guard here are quite content knowing our efforts here are fun and highly educational pastimes. For me, I love history and the technical / scientific era between the late 1800's and 1960. I can read and study the vintage concepts for hours and be quite content...content knowing their fusion efforts were in earnest, but of limited use and in no way will achieve the ultimate goal.

Just enjoy the hobby.
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Richard Hull
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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

Yes, the early work was in deadly seriousness. The researchers were earnest and serious and made great use of often relatively limited funds of the period. Sherwoood was bathed in secrecy, (cold war). Finally, realizing that fusion was no big deal and not going to happen due to the major early efforts, they just opened the books to the world in an effort to share, (open source), and get others looking into fusion and reverse sharing.

The Russians really made some strides with their tokamak and we did a monkey- see-monkey-do trying to improve it.........seemingly forever and without end.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Rex Allers »

Richard, thanks for the mention of obtaining the actual Project Sherwood book. I decided to look. My first search results pointed to places like Amazon that had recent, paper-back printings for ~$60 or more. Next day I tried a shorter search and found some with better prices.

Some listings that looked good were on alibris.com. I never used them before but decided to go for an original 1958 hard-cover for < $9 including shipping. It came in less than a week. Very clean ex college-library book.

Book is small, 6-1/4 x 9-1/4 x 3/4", 216 pages. Chapter 1 is 14 pages, looks like a nice straight-forward intro to basic fusion principles. Some Appendix with good reference info. Rest of book looks like interesting accessible descriptions of what was going on at the time.

Here's a link to their current listings at various but affordable prices.
https://www.alibris.com/Project-Sherwoo ... ?matches=9#
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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

As always, in specific titled, used books, prices range from a pittance to grossly and embarrassingly over priced. I tend to use ABE American Book Exchange and it has similar ranges of low prices to exorbitant in their listings. A number of the books are sent postage free.

I have amassed a rather fabulous scientific, but mostly nuclear library. I have even indulged myself with a few special first editions.

As with all such books there are a few that I just constantly go to for reference as they are the best of the best and always tend to contain just what I have questions about. I typically have a pristine copy bought and retained for my formal library. (10-40 dollar range). I also deliberately buy a rather ratty copy to keep in my two shelf lab library. ($5-$15 max) These poor copies have my yellow highlighting, oil soaked, smudged finger prints and glued-on tabs for quick access marring them forever, but ready for use in the highly active lab area.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Just a quick update on the pinch tube progress.
Working out some minor vacuum leaks, awaiting delivery on some supplies (metering valve, fittings, etc), building the spark gap, and determining the best course on the 30kv capacitor charging supply. The Fusor power supply is out of the question as I don't want to risk killing my xray transformers; especially since I have another fusor project starting up. I have a 60ma 20kv transformer (35 lbs of core) and a 14.4kv 5kva pole pig as possible starter resources. No hurry but a ways yet to go.

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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

Charging monster discharge caps is a snap. Tiny worthless HV supplies work great! Just put a suitable high ohm charging resistor in series with the supply and a good voltmeter across the cap. A small neon transformer with a trippler or quadrupler can easily supply 60kv, no problem and will pretty much self limit as the capacitor charges.
All my knowledge here goes way back to can crushers, coin shrinkers, repulsion coils and water arc guns. Charging a big, instantly lethal, high voltage capacitor is very easy.

Spark gaps and hydrogen thyratrons make the best high current switches if you can't afford or obtain a Maxwell pressurized, triggered switch.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Thanks Richard. I'll go the route of the tripler. Parts on the way.

Btw, back in the early 2000's I purchased your Fusor VHS tapes and have wondered if you converted any of it to DVD?
Did you make any cassettes on the water arc experiments as well?

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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

Everything is converted to DVD and I haven't produced a new video since 2001. I used the Amiga and its Video Toaster add-on in the early 90's to produce all the videos.

My 24 page, original catalog listing and directory of what is on each tape is still valid. I have placed the old paper catalog within a bunch of word files which can be sent via e-mail.

I ended all VHS tape sales in 2005 and have sent out only DVD's since that time.

I have thought about doing a new fusor educational video, but have been slow to move. The first two videos were produced in 1999 and 2000 and upon reviewing them I find them "charming" and issued when I was but a "babe in the fusion woods". They are just embarrassing enough to set me to consider a more modern exposition.

I am only given pause due to the very nature of the fusor.net completeness on the subject and the vast store of data here that would be nearly impossible to fold into a 2 hour video.

Thanks for the kick in the butt on this, however. Such an effort just slipped one notch up on the to-do-maybe list.

Richard Hull

P.S. Note: This is far off topic and I apologize to the originator of this thread. I might throw more light on this in my trading post store in future.

P.P.S. OOOPs! Mark originated this thread!!!.....As it is his thread, I am far less apologetic. He asked....I answered.
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Dennis P Brown »

A follow up on your post about the 20 kV supply transformer you do have. I used a 32 kV transformer with similar current out put and while fusion was ok (between 100 k to 200 k neutrons) it didn't exactly overwhelm my counter. While a 20 kV high current supply will create neutrons, the rate might be very low for a standard chamber. I've seen that a 2.75 inch cross was used and got neutron levls similar to better than mine using just 19 - 20 kV. So, do consider a fusor chamber using a small cross for that 20 kV supply. I think that is your best method for that x-former type.

Off your topic but does relate to the fusion viability issue. Heavy ion fusion via inertial drive might very well achieve very high level net power fusion. This type of fusion drive was never allowed to progress (far too close to weapons.) That type of system (vastly superior to the long wavelength laser of NIF) has real possibilities using straight forward physics and might be a possible path to economical fusion - just that no one has every really tried it (past a minor system built at Los Alamos) since only government labs can afford the accelerators and due to concerns about weapon physics, can't do that type of work.
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Based on Richards suggestion I’ll be charging the pulse cap with a 3 stage voltage multiplier. All the parts are in and that component should be completed this afternoon.

Other than working on the new Fusor, my big delay with Columbus has been the spark gap or trigger. I’ll most likely start with a basic 1cm gap for 30kV and then upgrade later to a trigatron design.

After a test shot with air plasma, I’ll assemble the PEM Cell so it can adapt to both the Columbus and cross Fusor platforms.

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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

Of course, As long noted with pulsed, putt-putt fusion devices. The proof of fusion is best done with bubble detectors, or, if potent enough, activation efforts.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Activation will be the first attempt followed by getting one of the bubble detectors. But I can’t imagine trying till i swap in the quartz tube.

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Re: Columbus-I Pinch Tube Build

Post by Robert Dwyer »

It would also be interesting to see the neutron and gamma pulse waveforms with a scintillator/pmt or perhaps some sort time-of-flight detectors. Of course that is easier said than done, but the waveforms of the radiation could tell you a lot, and with enough distance you could, based on timing of the pulses to the pinch, show separate gamma and neutron pulses which could also help prove fusion, besides Bubble dosimeters and activation. You could back out the energy spectra of the neutrons as well which would be interesting. I don't know too much about the dynamics of this design pinch, but im guessing that if you see any M=0 instabilities like in a plasma focus pinch, your fusion may come from beam target interactions which would give a slightly higher neutron energy spectra.
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

That would be a fun secondary project Robert. Once things are up and stable I may give it a go.

For a future iteration, I'm considering a moderately scaled down version where I can increase the cyclic rate of the discharges. While maintaining 30kV, I'm pondering how low in pulse cap value I can go and still generate detectable neutrons. Similar to the smaller volume Fusors (eg. 2.75 cross), maybe dropping the volume from a 17" long / 2" dia quartz tube to a 8.5" / 1" dia tube will allow for unexpected adjustment, hence the possibility of 5uF or considerably less. If the cyclic rate was high enough, detectable neutrons below 1uF may be possible. As indicated earlier by many, a bubble detector would be the best detection method for such a putt-putt type system. I can only imagine the electrical QRM and havoc it would wreak on normal detection gear at 20pps or greater.

Regarding my current (original) arrangement, I'm hoping to test it with air later next week. Deuterium soon after followed by the quartz tube upgrade.

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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

I agree. With a smaller volume, tube the discharge current should increase, if all other factors held constant (same as with cylindrical wire diameter.) rather rapid rep rates with a proper switch can work well with 0.5uf in a low inductance circuit.

As activation will save a lot of money over Bubble dosimeter costs, the system needed to get detectable activation will demand a lot from the experimenter in controlling the savaging of the tube's internal environment, allowing it to function long enough to attain suitable activation.

Note!! With any pulsed-discharge system at elevated voltages the X-ray pulse will be fearsome!!! Remember!!! The voltage of the discharge determines the x-ray energies. The current determines the number of x-ray photons produced, (intensity of the x-ray blast). There is a vast gulf affixed between 30kv @10ma and 30kv @3,000 amps! The actual dosing to a human, on a pulsed system, is a function of rep-rate and current in each pulse.

Be mindful of shielding and the inverse square law in this type of experiment as it is, as usual, all about safety from X-rays and not neutrons.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Excellent and most appreciated warning about the xray issue Richard. An added benefit of the smaller size will be the ease of encasing it within the multitude of 26lb lead bricks that I currently have on hand.

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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Here’s a quickly pieced together concept for a smaller, high cyclic rate pinch tube assembly. Ill probably start construction on this sometime in July.

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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

Just a quick update on this. I’m still slowly progressing towards a test shot very soon. Working on the Fusor and domestic projects have recently taken priority, so this got the back seat for awhile. The other hangup is pulse neutron detection which leaves me with either a costly BTI purchase or the use of CR39 plastic. If I use CR39, I plan to use the Fusors neutrons to establish what I should be looking for in the plastic after a pulse shot. The only other method would be activation but I’m concerned that such a cyclic rate will exceed the thermal limits of my pricy fused quartz discharge tube.

I still plan on firing the larger tube I built in the beginning of the year but this smaller one will be first. Currently waiting on a special KF25 fitting and a needle valve.

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Re: Columbus-I Pinch Tube Build

Post by Richard Hull »

Thanks for the update. If you get your pinch tube working it will be the first attempt to actually use a pulsed fusion system (putt-putt) here at fusor.net. You are very wise to be concerned about neutron detection issues with pulsed fusion. I would say that doing it right would be one of the most difficult tasks facing you. The issue is it would have to be bullet proof and really believable. (neutron rates). I would go with either activation or the absolute unassailable results would be the BTI route. As you say, that is expensive and the activation route would require long term pulsing which might force undesirable thermal thermal issues on your system.

All the best in a tough situation. You will be the pioneer here for all of us. I anxiously await running reports of this interesting pulsed system. The radiation reports can come once the operation is well in hand.

Richard Hull
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Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Columbus-I Pinch Tube Build

Post by Mark Rowley »

While waiting on some parts for the small unit I decided to resume work on the big tube posted about earlier in this thread. Also, since I took delivery on a bubble detector, that leaves me about 4 months to conduct every test at my disposal before it expires.

Capacitor charging circuit was finally assembled allowing a full 11k Joule charge at 40kV in about 1 minute. Once done I spent two afternoons putting the disposable / interim Pyrex insulator through all the motions. In addition to a couple dozen low power shots with air, I attempted 4 shots with D2 at known fusion inducing power specs. Those being 300mTorr deuterium, 28kV, 5500 Joules) As expected, the Pyrex tube was not suitable for generating a detectable level of fusion reactions. The sodium and boron in the glass mixture poisons the plasma causing a variety of problems. Pinch duration is reduced by the hot plasma conducting along the Pyrex walls. In doing so, more boron and sodium shears off into the plasma poisoning it. All of which was indicated in the original Los Alamos and Livermore tests in the mid to early 1950’s. Using fused quartz essentially annihilates these problems and increases the neutron/fusion yield by 100 times (also stated in the Livermore and Los Alamos reports). Fused quartz being somewhat expensive, I decided to first use Pyrex for prototype / stress testing purposes. It served well and much was learned in the process.

I’ve also been entertaining thoughts of a pre-ionizer which was used in the earlier systems. Establishing a small pinch effect to remove the plasma from the walls prior to kicking in the main charge has proven to be a valuable addition. Can’t find much info on linear pinch pre-ionizers so this may take awhile to learn about. No doubt there are a ton of specifics to making it work.

After the last shot, I noticed some slight scoring or fracturing along the circumference of the tube. When I removed the tube from the return conductor it was evident the scoring was extensive and went the entire length of the tube (see pic). Interestingly, the small fractures are actually a pattern consisting of a multitude of circles that go around the circumference of the tube from end to end. This effect is not deep and only localized to depth of a mil or less on the inside of the tube. The outside is still like new. There are no lengthwise or linear fractures along the tubes axis. Interesting effect that I have little explanation for.

The higher powered shots seemed like they have the possibility of adding physical stress to the tube. So to remove any chance of that contributing to a catastrophic fracture, I’ll be moving the spark gap away from the tube. It should also allow for an easier design to add or subtract inductance and install a Rogowski coil.

So far this has been an equally fun and educational project as the Fusor.

Mark Rowley
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