Matt Gibson Fusor

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Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Figured I’d start working on a new PSU in tandem with my current efforts to fix the Glassman. I already have a jumpstart:

4 stage, half wave, CW multiplier using wima fkp1 capacitors (2 in series for 12kV and 0.034uF). Diodes are 2CL2FM (20kV, 100mA, 100nS). I put this away after a quick test showed that it was awfully dangerous! Accidental discharges sound like gunfire. Multiplier is under oil.

Transformer is a high frequency ferrite on monster sized cores that I got from Steve Haid (a member here).

Resistor string came from years ago. 18 200Mohm 2w resistors. I’ll use this (probably remove/jumper some resistors based on what uA meter I can find) for voltage measurement. Current will be measured on the high side, suspended in air.

Per https://www.extremeelectronics.co.uk/ca ... alculator/, I should be able to push 20mA and have under 600v ripple. I’ll probably push these capacitors higher by 30% and still have thousands of hours of run time.

To do: I need a good driver that offers easy to control current and voltage. Probably some PWM IC and half/full bridge IGBTs or MOSFETS. Will also need a good isolation transformer (1500w toroid maybe?)
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Finn Hammer
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Re: Matt Gibson Fusor

Post by Finn Hammer »

Matt,
Looking as a good start, however:

Current is current, and it is the same everywhere in the circuit.
Can you give just one good reason for measuring it on the high side, when it can be measured as a voltage across a resistor in the ground leg of the multiplier?

Cheers, Finn Hammer
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Hi Finn,

Trying to get wires in and out of the multiplier enclosure with oil and all seemed like a bother. I have a lightweight 100uA analog meter that “hangs” nicely in between my ballast resistor and my feed through toroid. Only drawback is that I can’t feed this into any sort of recorder or use something digital since it’s at high side, but that could be for later down the road.

Trying to measure current via the ground from my fusor chamber gave me a “0”. I think this is because I have multiple paths to ground due to me using a metal frame with multiple equipment that all have their own grounds?

Edit: Thinking it over, I may just fit a sense resistor in there for current, that way I’m not trying to eyeball things in multiple places :-)

-Matt
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Richard Hull
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Re: Matt Gibson Fusor

Post by Richard Hull »

Now!!! This is a real supply!!!! If this gets implemented, you are good to go! You have assembled the right stuff there. It has a good bit of ass behind it and it is ready to go to work. HF supplies are not the problem, it is the components often used in them. I would stick with 25khz and under. Those caps ought to be suitable filtering for even 10khz or less at the current you might need. Be careful! "You are not in Kansas any more"

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
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Thanks, Richard!

I think I’m going to try to fit the HF transformer in with the multiplier so that it’s all under oil…Just need to get a bigger box and more gallons of mineral oil. Tractor Supply already thought that I had one sick horse after I bought several gallons before…

Gonna get some G10 boards on order to start mounting stuff to.

While I work out the driver details, I’ll go back to using a car amp and signal generator for testing. I blew up the last one…

Still not giving up on my little Glassman. I’m bound and determined to make it work for Silver activation and keep me satisfied until I can get this big boy going…Got to get my daily fix in now that I got a taste!
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Is there any reason to submerge the entire transformer in oil vs just it’s secondary side? If not, I’d have the primary sticking up and out of the oil. This would let me use a shallower box and less oil :-)
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Richard Hull
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Re: Matt Gibson Fusor

Post by Richard Hull »

An odd question to all but the inventive and impoverished. Sure! Dunk the nasty end of the thing. The low voltage end may rise above the waves. Make sure to send a photo of this curiosity for all to enjoy.

Odd looking things can be flawlessly functional but induce a bit of humor to those use to specific methodologies.

A true story:

I started the Richmond Robotics Group back in 1982. In those days you took a 6502 @ 1mhz, added an EPROM, about 4 k of memory and the 6522, its' peripheral port IC. This was to make an assembly language based micro controller for your robot. Most of us were used to point to point wire wrap and would choose a suitable length of wire and wrap to the IC sockets in a nice flush manner routing the wires not directly, but in a serviceable manner around the bottom of the PC board. Needless to say, this hand-work produced well over 200 individual connections and 100 or more wires from about 2-40 pin chips, 3-24 pin chips and about 7-16pin chips. The wire layout was confused but very neat and laid flat along the bottom of the board, often held in, well routed and flat bundles with a dab of glue once the board proved itself working. They were works of wire wrap art. A just and well deserved pride in such efforts were well received.

One of our non-electronic members also made a board that worked great, but used all precut 4" wires that he bought to avoid the hundreds of precise wire cuttings and strippings needed as the rest of us had struggled through as a love's labor. He came to a monthly meeting with his functional pride and joy. The moment he presented it from within the box in which he had brought it, laughter erupted from every member of the group, tears of mirth ran down the cheeks of the hyper amused. He presented his board with a perfectly symmetrical hemisphere of about a 3-inch radius done in a myriad of blue 4-inch wire wrap wires. A board atop a 6 inch diameter hemisphere of insanely close, knotted wires. Comments like... "Light will not penetrate it!".... "Only a wire wrapping spider could do that!".... and "Where is the socket for that ball joint?", were elicited. It was a marvel to behold! Reference to it was made all throughout the meeting. How one would mount such a finished processor board also was a topic of discussion into hyperbole with more mirth.

Alas, upon leaving that meeting, the poor guy never returned. We were laughing, not at him, but his unusual creation born out of a work-around to save time and use pre-cut and stripped fixed length wire. Sometimes we are all laughed at for what we say or do. The key is to learn when the laughter is directed out of friendship and in the spirit of the moment and not as a derisive shame upon you, as a person, by a mean spirited person or persons. Learn to laugh at yourself. Enjoy life. Thin-skins are not the ticket for engineering or scientific teams for at some point, everyone is laughed at or found in a faux pas.

The lesson is something functional may look odd and elicit some humorous comments from your peers, but do not let it bother you if it works.

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
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Richard, you should have seen how I constructed my projects during HS and college! Functional, but ugly…

I tend to ease into something and then improve it as I succeed.

A good example of funny looking but working is my 20kV feed through sporting a “top hat”. The 20kV feed through was on eBay for less than half the price of a 30kV one…Looks funny but I haven’t had a single arc over nor do I see any corona discharge (lights off) at 40kV.

I’ll definitely take plenty of pictures as I progress! Going to put a bit of work into form as well as function, as I’m pretty well twitterpated by this project now.
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Silver activation claim:

https://youtu.be/mdqt3ac6p1E

Ran for about 6mins, -40kV, 5mA (I think), 14.3microns.

Before anyone says anything, yes my probe has been contaminated. I have ALOT of uranium minerals and didn’t realize what I was doing. Background is 1200cpm because of this contamination. Silver activation is hitting just over 2200cpm, so 1000cpm.
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Richard Hull
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Re: Matt Gibson Fusor

Post by Richard Hull »

Great work Matt you are in the elite fusioneers.

How did you contaminate the probe?
It can be easy to do by leaving the probe a very short distance from a very strong alpha emitter like radium for a protracted period. The radon production with radium decay and other of its daughters decaying in relative equilibrium will recoil and load up the mica with the various daughter isotope atoms that slam into the mica and bury themselves in it.

Leaving a probe in a grossly unhealthy atmosphere or radon gas will also do this. Keeping a probe free of this involves merely capping it when not in use. When in use, a 10 mil poly bag cover will keep the alpha and daughter recoiling atoms off the mica and still detect the beta radiation and some limiting gamma as the probe is not too sensitive to gamma.

Most of the contamination will go away in a few days or weeks and you will still have a slightly elevated background that is not significant due to the small number of the late lead and polonium 210 atoms of long half life debris still trapped.

Needless to say, never leave the probe facing upwards and open or when measuring ore samples due to microscopic ore debris falling due to gravity onto the mica during handling. Always measure face down over any source and never let the wire guard mesh touch any radioactive.

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
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Hi Richard,

Great to hear! It was definitely exciting to see.

I had a bad practice of laying uranium rocks (Autunite and torbernite included) directly on the probe screen. Since mine are all on the high end, I didn’t notice that I was contaminating the probe (my rocks all need to be on the x100 scale). Somewhere in there is a spec (- black light might help if it’s Autunite in there). :-( It’s probably risky to attempt to remove it, so I just keep it for my rocks. If I find a good deal on a new one, I’ll probably get it :-)

1000cpm is a start, I’ll keep working on the upgraded psu so that I can really cook it.

-Matt
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Richard Hull
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Re: Matt Gibson Fusor

Post by Richard Hull »

Subjecting a nice 2" pancake to a long 12 year period of even infrequent measuring of many hot rocks where the screen almost, but does not touch the screen from above, has my lab NIM based GM have a rather permanent background of 250 cpm. As you can see, the GM tube is in a very short piece of 3-inch PNC pipe which can be raised or lower over a specimen. the NIM modules make up the counter where I feed to both a Ortec rate meter and then a Tennelec digital timer-scaler. I use this system more than any of my other instruments for detailed quantitative data. The hand held portable stuff is for sniffing around and remote work. I have a couple of spare LND 7311 pancake tubes. I think it is time to retire this one and that I-Hop to slip in a fresh pancake.

Richard Hull
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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
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Richard,

Any idea if contaminated probes are actually damaged by having a spec constantly blasting it? I’m thinking about how lung tissue would react to having alpha particles bombard it 24/7. I think I’ll look at my probe under black light later to see if I can find the spec. Autunite is the most crumbly that I’ve used on it…

-Matt
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Richard Hull
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Re: Matt Gibson Fusor

Post by Richard Hull »

I can't image a long bombardment of Alphas killing a mica windowed probe. I can imagine very much a background of 8,000cpm or more in such an instance of a virtual forever bombardment due to daughter attachments. The counting gas could suffer a bit but not likely, especially if no voltage is applied to shock the gas into counting via gas multiplication. (Assuming the probe is halogen quenched)

For the same recoil argument sticking daughter atoms to the mica, so goes the counter argument that those second daughters, in decaying to a third, might free the heavy, original parent heavy nucleus from the mica. I am sure it happens, but one should not let it happen at all.

I have no issues with sticking a hyper hot rock under the head in the images I included and dropping and locking the head in place with the screen 1-2mm from the specimen or item to be measured. I did put a copper screen on my homemade GM detector head. However, If it is hyper hot, I might only freeze the count at 30 sec and double the count as it is usually well over 20,000 counts in 30 seconds. Doubling that would not rip my statistically laissez-faire doubling to bits so far as accuracy of the count is concerned at the single sigma level.

Bill Kolb, my good friend, and even Carl Willis said to me, "You should not count the alphas as it gives a wrong impression on how hot the rock really is" I say, "What!!" It gives a full impression of how hot the rock is! Why own a superb 2" mica-windowed GM detector and not let it count the alphas??? Why did you buy a mica windowed detector in the first place if not to make it sensitive to alpha particle radiation? Sure, at 3-inches from the rock, there are no alphas, The betas can go out to a meter. The gamma's which are barely detected can leave the lab and go through the neighbor's dog! My retort is why not the alphas?

I think this mind set was out of some false sense of honesty to the average person or rock hound purchasing one of their ore specimens. Bill and Carl realize the average no-nothing, if he has a GM counter, it will be a yellow civil defense type or one of the ubiquitous $90 Russian tubed GM counters, both having solid metal envelopes that will never count alpha. If you count the alpha like I do, and say your ore sample counts 80k cpm and the no-nothings get 35 K with no Alpha, they might feel lied to. I have no such qualms as I report the full radiation. If they have a crummy detection setup, it ain't my fault, I was honest with them.

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
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

I used to use a CDV700 to give my uranium ore readings on eBay. I saw that competition was using pancake probes and made mine look pitiful in comparison. That’s when I decided to get my Ludlum with the 44-9 :-) It definitely paid off…

Most of my rocks max out the cdv700 (shield open) and a few max it out shield closed, so I really needed something with a higher range anyways.

A few of my rocks almost max out the Ludlum.

I’ve found that some rocks are much more alpha rich than others, so I’d agree that alpha should be counted.
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Richard Hull
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Re: Matt Gibson Fusor

Post by Richard Hull »

Good man! Why understate a quantitative reality. Even and especially with the big 2-inch pancakes, missed counts kick in at a bit over 50,000 cpm and as I have specimens that actually count to 250,000 cpm with the pancake probe, can you imagine the losses and counts missed there! Good, reliable counting at that level is just out of the window. 250,000 cpm is stunningly under counted.

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
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

I always felt that the more information, the better. I do make sure to give the details of the reads so the buyer knew that his cdv700 wasn’t going to have the same reading. My rocks always max those out anyways, so they were always happy!

Decided to do some more work towards getting my own psu working. I ordered a 3000w rms car amp that can go up to 30khz. That should be plenty of power and frequency response to not clip when running where I want to be. I’ll feed a signal generator into it to control voltage and current.

Also reworked my resistor divider board so that my 25uA meter reads 75kV at full scale. I figured 75kV is the max that I’m going to ever be able to do anytime soon. This will get bolted to some plexiglass along with the meter for voltage and a meter for current. It’s probably massive overkill but I’ve had it for years and glad to finally show it a good time.
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Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Time for an update!

Managed to get my multiplier + HF ferrite psu going. Pushed my little 20kV feed through up to 57kV before flashing it over pretty regularly so I splurged on a new 30kV feed through. This got me to near 65kV before I blew my multiplier. I’m now waiting on some capacitors to swap out the two that failed.

Before blowing things up, I was able to push things pretty hard compared to my Glassman. My highest run (that I believe is accurate) got me to 60mR/Hr on the Ludlum Priscilla. This was pushing near 60kV and 7-8mA at 12 microns.

My best silver activation got me to 2800cpm (up from 1200cpm): 55kV 10mA 12 microns for 2.5 mins.

I had to add some layers of lead sheet all around the chamber as the x rays began pouring out once I broke past 40kV.

Future updates planned:

1-Build a new 6 stage full wave multiplier so that I can push higher voltages and not fry my multiplier.
2-Better driver. Right now I’m using a function generator, car amp, and 12v 83A dc psu. The car amp gets extremely hot, so I know it’s not happy. I’ll probably go the Chinese zvs plus variac route before I finally build something using a PWM and half bridge. At least the car amp is the only thing getting hot, so it would seem the rest has plenty of Hp left.
3-More lead/better shielding.
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Dennis P Brown
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Re: Matt Gibson Fusor

Post by Dennis P Brown »

Really nice build. Very impressive results for a home build Voltage Multiplier. One of the more practical builds I've seen. I have a Chinese ZVS but have been able to reborrow the x-former I used before (Really wish they'd just sell it to me - not like they use it … .)

Really happy Fusor is back on line. A huge thanks to those that put in the massive effort to fix it!
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Thanks, Dennis. I’m striving to keep this clean and simple looking, easy to work on.

Placed my order for the 6 stage capacitors (47nF 6000v wima fkp1) a 1500VA toroid transformer (Hammond 117v primary and 60v secondary to use for isolation) and have another Fibox enclosure coming to house the 6 stage multiplier. I have a 1500w Chinese zvs sitting in a box already…

Hoping to melt my grid down with this “round 3” for the PSU. :-)
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Rich Feldman
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Re: Matt Gibson Fusor

Post by Rich Feldman »

Nice work there, Matt. Very inspiring for HV power supply enthusiasts.

Off topic: looks like fusor.net is back in business. Time to check recent admin posts, and spot check some very old posts & couple-years-old posts.
All models are wrong; some models are useful. -- George Box
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Credit goes to Steven Haid, Mark Rowley, and Finn Hammer…Either got parts from them, and/or inspiration from them. Happy to add another proof that this is the best way forward now that the 1ton X ray xfmrs are gone…
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

Got the multiplier repaired. I had to use some 47nF capacitors as the 68nF ones are back ordered for months. It fired right back up…

But then as I tried to push beyond 50kV, I heard popping noises again. I shut down, discharged each capacitor (learned the painful way that they hold a charge despite shorting the bank out) and then probed around. Each capacitor measures exactly its rated capacitance and each diode tested good.

Bolted it all back together and pushed it up a little over 45kV. No popping noises, current draw was 15mA, pressure is around 12 microns. Only drawback is neutron output is only 20mR/hr at this voltage :-(

Decided to order a few more of the 47nF capacitors just in case…

Still waiting on my big order of capacitors to arrive so that I can start constructing the 6 stage full wave version of this. Hoping this will let me run at 75kV all day long without any failures.
Matt_Gibson
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Re: Matt Gibson Fusor

Post by Matt_Gibson »

I have a quick question that is bugging me:

Where is the optimal placement for the deuterium entry into the chamber? Right now, I have it entering from below, where the turbo connects. I’ve been thinking about redoing this such that it enters directly into the chamber (from the rear). Here is a picture of the setup:
6890D7AF-8439-4421-BDAB-A9E212A044A8.jpeg
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Richard Hull
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Re: Matt Gibson Fusor

Post by Richard Hull »

At our vacuum level it is of little importance but I always locate my gas inlet port as far distant from the large vacuum port as possible. Like I say, we are in molecular flow mode and the gas let in is not subject to the early stages in pumping of viscous flow. The admitted gas molecules are moving faster than a rifle bullet individually with a long mean free path and will instantly disperse all over the chamber.

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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