Matt Gibson Fusor

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Hi Richard,

I think that this detector actually measures in mR/hr with a conversion of 350cpm/1mR/hr. I used the Matlab code provided in the thread dedicated to these detectors to generate the background and the run with deuterium.

Looking at the raw data, many 1/2second hits were over 2mR/hr.

Maybe the actual CPM should be 100*350?

Edit: Here is a graph of the data
1_1_22_run1.jpg
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Matt Gibson Fusor

Post by Richard Hull »

Matt, I tend to agree with you here. Others who read this please chime in I think 35,000 CPM is within reason for the stated run data and I think I fully understand Matt's logic and reduction here.

If other users of this specific counter system agree, I will put Matt in the neutron club. Matt, You need to grab some pure silver, slap it in a moderator and a GM counter, if this is real.

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
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Hi Richard,

I have some 999 silver sheet left over from my ruby laser project, guess that ought to work? As for a moderator, I don’t have anything handy. Where is everyone getting their HDPE from? Would two 1” pieces of HDPE be sufficient for activation?

-Matt
User avatar
Joe Gayo
Posts: 404
Joined: Sun Jan 06, 2019 9:34 pm
Real name: Joe Gayo
Location: USA

Re: Matt Gibson Fusor

Post by Joe Gayo »

Are you using Andrew S.'s code as is? I think he may already be converting the mrem value to counts.

I'm also surprised by the 0.5 sec intervals with no measured counts.
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

I am using Andrew’s code…

There were a few instances where the plasma went out while I was playing with the pressure, maybe that’s the cause of the zero counts?
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Update:

I’ve been playing with the deuterium flow rate and found that cranking it up and opening the chamber valve (to maintain a pressure in the 14micron range) more than doubled the reading.

Before, I was hitting over 2mR/hr on the meter. Now I am hitting over 5mR/hr. Using Andrew’s Matlab code, I am getting a CPM value of 183 (up from 114).

So how do I rule out x rays and noise? Should I split some de-ionized water and run hydrogen to see if I still get readings?

Not sure how to interpret what I am seeing…Neutrons? If so, what do these readings actually translate to? I am maxing out at 39/40kV at 7mA and around 14 microns. Not sure how to get my current draw up. My psu can go to 15mA.

Maybe I need to dry my deuterium?
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Update:

Some more playing around. This time, I hit over 8mR/Hr (Ludlum value) a few times. This occurred at 40kV@7mA and 15.2 microns. In order to achieve this combo, I have to have my system running at full tilt (Deuterium flowing at 10sccm and chamber valve full open with the turbo going at 100%).

Here is a graph of the raw data from the Ludlum. X-axis is time in 1/2 seconds and Y-axis is mR/Hr from the Ludlum. You can see me adjusting/fidgeting with the Deuterium flow and the chamber valve. As I crank up the Deuterium, the mR/Hr drops and then gradually climbs again. The large drop in mR/Hr occurred when I just decided to go for broke and janked it up to 10sccm (Max flow). Run time was a little over 16 mins. At this point, the Ludlum is sounding irate…If not neutrons, what could all of this be?

I have some HDPE coming...Hopefully I'll be able to active some silver and then call this a success?


Best_Run.pdf
(182.33 KiB) Downloaded 251 times
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Matt Gibson Fusor

Post by Richard Hull »

Matt,
What you are measuring are 100% neutrons! Welcome to the neutron club! I will log you in. These Ludlums have proven themselves in reports here and your results are so close to mine that they could only be neutrons you are seeing! Read my report of my run on the same date as you ran your system and my comparison of our results, bolstering my variability FAQ in the neutron and radiation forum.

I hope this is not comparing apples and oranges. I run a sphere. I am back in the biz to compare various methods of measuring and I am happy to say that within 10% or more they all agree. I post here as the conditions are similar in some ways to Matt's work with a totally different measuring scheme. I was amazed at the close similarities of our results, considering the difference in devices and methods of measurement.

I will add a modified, combined reply relating Matt's reply above and my own here to my FAQ on the variability of fusion rate in a fusor in the neutron and radiation forum FAQ I recently posted.

I now have my Rem ball and my PNC-1 working along with my normal 3He detector.

Last night's run topped out at a bit over 500k n/s based on the 3He calibration. I activated Rhodium to 22 times background (background here is about 4 times most folks GM background) both the mrem/hr reading of the Rem ball and the PNC-1 block moderators were varying over 10 second intervals, up and down as noted in other recent postings by me. This matched Matt's wild second based insane variations and his more moderate time averaged variations. My analog variations, (real time needle swings), were on the order of his moderated average variations in mrem/hr.

My Data: 41kv, 11ma, 10microns D2,....At this operating point PNC-1: 6.8 - 7.4 mrem/hr.....Rem ball/PNR-4 lin-log reading: 6.6 - 7.8 mrem/hr....Both the ball and the PNC-1 block moderators jammed against the fusor. 3He count was 86,205 cpm (translates to over 517,000 n/s TIER).... Rhodium peak activation was ~1300cpm (rhodium's very small surface area foil exposed 2pi to GM tube = ~6 sq cm).

1. I have to believe Matt is doing fusion and that his posted reduction above proves my point that all fusors are not steady fusing entities but have, on the micro time scale, immense fusion output differentials. (Matt's and other's data)....New Ludlum micro dose delivery detectors.
2. However, when analog averaged over10-20 seconds, a net emission of fusion neutrons swings about a common point +/-10%.....(Remball/PNC-1)
3. One full minute hard digital counts can vary about +/-2%.... (3He).
Activation over time and bubble dosimeters would be the pure net emission or dose total indicator.

As noted before and stated in my FAQ....

The fusor due to its simplicity with many modalities with cross interference between them is not a steady fusioning system on extremely small time scales but over a number of minutes can be reduced to a reliable net dose device if all of the parameters in its operation are held steady. Even a morass of confused emission with steady parameters feeding it will , by statistical analysis over time, settle into a usable average emission rate and TIER, in our case.

Note: all of this valuable neutron radiation data on this new Ludlum system should never appear in images du jour or in the construction forums. It belongs in the neutron and radiation forum... Oh well, we do let such things smoothly flow from one thing to another, quite innocently I might add. I hope all this good stuff related to neutron counting and measurement is not lost in future buried hopelessly in the images forum here. It is for this reason that I will edit this into the neutron variability FAQ post as a reply...

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
User avatar
Finn Hammer
Posts: 298
Joined: Sat Mar 05, 2016 7:21 am
Real name: Finn Hammer
Contact:

Re: Matt Gibson Fusor

Post by Finn Hammer »

As promised, here are data from my cube, as recorded with the Ludlum 2363, at 40kV, 7mA, same as Matt's fusion claim run.
It will be noted that the cube reaches higher numbers than Matt's fusor does, but then the pressure is also so much higher, 28 microns as opposed to Matt's 15.

Parameters at running time
Parameters at running time

Here are the recorded numbers, from the first 10 minutes of a 13 minutes run:

Matt1.JPG

Doing a bit of calc on the numbers: there is an average of 25mRem/hour multiplied by 350 gives 8750 cpm. Divided by 5670 to get "x"e5n/s, gives 1.54e5n/s
I recorded the activation result with silver, 45kcpm, as seen on this short video clip:

EDIT!!! The cpm recorded was 4.5kcpm, I got the multiplier setting wrong.


https://youtu.be/9d-5uwQ-caA


Matt, welcome in the neutron club!

Cheers, Finn Hammer
Last edited by Finn Hammer on Tue Jan 04, 2022 4:58 am, edited 2 times in total.
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Matt Gibson Fusor

Post by Richard Hull »

Nearly double the fusion fuel in a smaller chamber that is known to do significant BOT via concentrated end plate wall loading and you are doing about three times more fusion. I believe it.

I also believe you are doing far over a mega fusions/second at this level. If you get the bubble detectors I think you will find this to be the case.

I see it is now almost 5AM in the morning....Now out to the lab for a fusion run, then back into the house for bed time at about 7AM.

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
User avatar
Finn Hammer
Posts: 298
Joined: Sat Mar 05, 2016 7:21 am
Real name: Finn Hammer
Contact:

Re: Matt Gibson Fusor

Post by Finn Hammer »

Just a short note, the above post of mine, boasted 45kcpm, but that was wrong, it was 4.5kcpm, my bad.

This has been edited in the original post.

Cheers, Finn Hammer
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Richard, Finn - Thank you very much, excellent news! I am excited!

I definitely couldn’t have done it without the help from you guys and many others that came before, succeeded, and provided their results, knowledge, and expertise to this forum…I’ll be sure to well document my future efforts as I continue on!

Next up will be the silver activation and then rhodium (I’m watching for some good deals as the price of rhodium looks to be down). I need my Hdpe to hurry up!

After that, I need to upgrade me PSU. I have plenty of current capacity left, but find that the fusor really starts going once I break past 35kV. At 40kV, it’s begging for more volts!

Also need to get some air moving across this thing as it heats up FAST.

Edit: Now I need to look into calculations for TIER for this fusor/scintillator combo.

-Matt
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Matt Gibson Fusor

Post by Richard Hull »

Matt, Your fusor has a wire grid if I remember. There will be hot spots, (good neutron emission), probably near the central region of the cross. This is where you need to put your moderator when activating and the Ludlum when counting. I bought my tiny Rhodium strip of foil when Rh was only $10,000/troy ounce. I paid a bit over $600 for it. I plan on buying a larger Rhodium target, but will wait until Rh drops well below $4000. Good luck on the Rhodium.

Definitely stick with 999 pure Silver for a while to get your "activation legs" on a firm footing. Sheet pure silver can be had from Rio Grande. Just make sure not to purchase Sterling silver sheet for it is not pure. (8% cooper content.) Coin silver is only 90% silver. Stay with "fine silver" .999pure.

Indium is also good. Go to Roto metals for small pieces of Indium and you can pound the stuff out with a hammer to sheeting. It is like play-dough. If you get a big chucky piece, melt it in a small pyrex glass or porcelain dish, it is easy. Get a flat piece of sheet steel and kind of sling-pour the metal out onto the sheet this should freeze into a longish slender mass that is less thick. A thin portion off this pour will respond much faster to being pounded out to a sheet-like activation target.

I appreciate your broad thanks for the help you have received. I am thankful for all that I have learned over these many years from others as well. It is well to realize that much of what you have read in the old posts and replies from others, perhaps long gone now, was of real value. Even though I have written the bulk of all FAQs, the responses from others in those FAQs have added much of critical value to them. That is the value of the term "open source" in this forum.

Recently due to a number of factors, the forums are alive with information and folks like you getting stuff done. This is always a good thing. We keep growing, learning and teaching.

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
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

I see what looks like two very very faint, purple, beams going side-to-side within the chamber, through the loop openings that make up the cathode. I don’t see any other beams. This looks a lot like what I see in the ring cathode design…Is this normal for a three ring wire cathode?

Anyways, putting the hammer on the side of the chamber produces the highest detection. No room for improvement there.

I am seeing plenty of condensation in my syringe, so I assume my fuel cell is producing “wet” deuterium. I will get some drierite on the way home today and add some to the syringe to see if this makes a difference. If so, I’ll plan for a better way of drying my deuterium rather than a half assed approach :-)

My system seems to be happy at 18.1 microns, 40kV-ish, and 7mA. If I raise the pressure, my voltage drops (and stays lower) while my current rises higher. Neutron production drops. I’m already at my max voltage so I can’t lower the pressure without tripping the psu off.

As I understand it, higher current will also increase neutron production? I have more than double the capacity available…Am I tapped out based on my chamber/cathode configuration?
User avatar
Liam David
Posts: 518
Joined: Sat Jan 25, 2014 5:30 pm
Real name: Liam David
Location: PPPL

Re: Matt Gibson Fusor

Post by Liam David »

Your chamber is cylindrical, so there will be a preferred plasma formation axis even with a spherical grid. Since your grid isn't perfectly symmetric, this effect is exacerbated.

Higher current for a given voltage = more neutrons, almost exactly in a linear relationship. Double current = double neutrons.

If the Glassman is cc/cv, I don't see why raising the pressure at 40 kV / 7mA drops the voltage unless you're current-limiting the supply via the front-panel knob. Raising the pressure should raise the current to 15 mA, only after which should the voltage drop.
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Matt Gibson Fusor

Post by Richard Hull »

Matt,
What you are telling me leads me to assume that your supply impedance is the limiting factor here. Beef is needed and it ain't there. Regardless of the supply ratings and claims, it is folding up with the addition of gas. This is actually quite the norm, however, with beefiness in the supply the voltage can be raised and the current will rise as well after adding more gas pressure. You have discovered your classic "rope limit" with your supply. Reducing the pressure should allow more voltage to be applied, sliding you up the cross sectional curve, but the current will be limited in the end, I would think. More of a watt limit maybe, at this point. Our supplies regardless of beefiness limit all but the most well heeled. Those with the ultra beefiness in their supplies will hit a voltage limit as some point where breakdown in the reactor will be the limit. Let us hope they have a more than adequate ballast or fabulous protection electronic guard dog for arc level protection. Even a 150kv 50ma supply coupled with a fusor, will see their combined limit due to any number of possible limiting factors.

I have 45kv as my voltage limit with an almost unlimitied current. However my ultimate limit in the heating at 45 kv @20ma and its 900 watt heating effect on my uncooled fusor will, in short order, create electron runaway with my tungsten wire grid. Please note the following realities I am faced with. My input 60hz AC current to the x-ray Xfrmer for smooth operation is about 250 volts (variac boost) at 4.5 amps and this happens at about 38kv out of the rectified DC supply. However to get the huge core saturation needed to claw my way to 45 KV @20 ma (900 DC watts) requires the AC input to be 250 volts @ 8 amps or 2000 RMS watts!!! Limits are limits and we learn to live with them. My poor X-ray transformer core and primary take it on the chin over about 41kv. The poor transformer hum in protestation is easily heard at my rope limit. Naturally 2000 watts in to get the 41kv @10.5ma 430 watts in my most recent run is fine with me and especially my power company, but I really feel for my poor transformer.

As I have said for years with the Tesla coils at 12,000 watt draw of Nemsis at its peak and now my fusor wasting energy......The power company and I have a deal going between us. They agree to give me all the power I am willing to pay for. At about 8.5 cents per KWhr, coupled with short burst usage, I do not see this in my monthly billing.

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
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Hi Liam,

I may need to check this to see if my current knob is fully rotated. I usually just rely on the indicator light that lets you know which is limiting the output (voltage or current can be set). It’s disappointing to have 600w available and only be using half.

Any thoughts on “wet” deuterium? I know that in general, anything else getting into the chamber will get in the way of the deuterium, but has anyone shown just how much wet deuterium affects operation?

How about temperature of the chamber? I’m hitting over 200F. At what temperature does performance begin to suffer?

Edit: Richard, does the load matter all that much to a supply like this? Seems it should be able to handle whatever is thrown at it up to its current/voltage limiting circuits. Maybe I should use a backup current meter to see if the PSU current meter is accurate?

-Matt
User avatar
Liam David
Posts: 518
Joined: Sat Jan 25, 2014 5:30 pm
Real name: Liam David
Location: PPPL

Re: Matt Gibson Fusor

Post by Liam David »

I'm not familiar with Glassman supplies but the light probably comes on relative to the knob setpoint and not necessarily the absolute limit. Check the knob!

I'm not aware of any quantitative studies on how wet deuterium affects operation (anyone?). Nonetheless, it's obviously best to have minimal water vapor. One would have to look at the charge exchange and scattering cross-sections to get an idea of the magnitude of the effect.

A hot chamber will outgas more water and other gases, and will reduce deuterium absorption which reduces beam-target fusion. I tend to stay below 100C, but more for my o-ring seals. I see a noticeable drop in performance above ~80C.
User avatar
Richard Hull
Moderator
Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Matt Gibson Fusor

Post by Richard Hull »

I am with Liam! I will usually end all running of my fusor at about 80 deg C as wall unloading coupled with electron runaway lay ahead. In a well adjusted fusor V I am usually up to about 800,000 TIER at this point, but it varies. After shut down the other night at 85C, with zero power applied it coasted nicely up to 98C before cooling in my 33 deg F lab. I assume this is stored thermal energy in the giant 8" CF rings.

If and when I do another fusor, I will endeavor to actively cool it in some fashion.

Yes, as Liam suggests, monkey around with you supply to see if you can do better. Claims by manufacturers will forever be just that. Read my neon transformer post. 15 kv @ 30 ma is a joke and an impossibility. 0.1 microns on a mechanical pump is a dream, as well.

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
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Sounds good guys…I’ll work on cooling, drying the gas, and may reach out to Glassman (they’ve been recently responsive) if I can’t get current to increase. I can’t imagine a multi thousand dollar (when new) psu would cut out at half the advertised specs without some other issue in play. Fingers crossed!
John Futter
Posts: 1848
Joined: Wed Apr 21, 2004 10:29 pm
Real name: John Futter
Contact:

Re: Matt Gibson Fusor

Post by John Futter »

you will find that your supply is responding to little arcs that are hitting the current limit so short in time that you are not seeing it on the current limit led.
You need to delve into the Glassman current control circuit and scope it. What value is your ballast resistor??
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Hi John,

I’m using a 50kOhm ballast resistor.

Would I be able to see anything happening in the chamber? It looks pretty stable to my eyes…

Every now and then, I do see the current flicker (very briefly drop low and immediately return to 7mA).
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Okay, so while I haven’t solved the issue with current, I did find a potential issue with the MFC…It leaks!

I let the syringe run out and saw that I’m still getting around 4 microns with the MFC valve open. Closing the valve allows me to run down below 0.1microns. Assuming it was the syringe, I removed it and put my finger over the hole to the barb. Still 4 microns. Taking off the barb and trying to plug the Kf25 to vcr4 adapter, 4 microns. I removed the MFC and twisted the adapter a litter harder…

STILL 4 MICRONS!

Do I have an internal issue at this point? Or are these vcr fittings just tricky to get right?

I then took off the adapter and tried plugging the hole directly to the input. Still leaks. The rate of the leak increases as I open the valve more and more, decreases as I close the valve.

What’s going on here?
User avatar
Liam David
Posts: 518
Joined: Sat Jan 25, 2014 5:30 pm
Real name: Liam David
Location: PPPL

Re: Matt Gibson Fusor

Post by Liam David »

MFCs almost always have a slow thru-leak and are not meant to be shutoff valves. If I leave the reservoir behind my MFC pressurized, it will cause the chamber pressure to rise to dozens of torr of deuterium overnight. Your finger won't be a good enough seal at 4 mtorr, and even if it were, the residual air upstream in the MFC will buffer the leak for a little while. Unless you have messed up sealing surfaces and gaskets, VCRs are hard to get wrong. Alternatively, are you sure it's related to the MFC?
Matt_Gibson
Posts: 505
Joined: Thu Sep 23, 2021 10:36 am
Real name: Matt Gibson

Re: Matt Gibson Fusor

Post by Matt_Gibson »

Hi Liam,

If that’s true, then maybe I overreacted…I was surprised to see my turbo unable to pull below 4 microns with the valve open and syringe connected…

While I don’t use the MFC as my main valve to the chamber (there’s a bellows valve connecting it to the chamber), it does hold pretty well on its own when closed. I can pull below 0.1 microns pretty quickly.

Is there a proper way to check that it’s functioning properly then? While it was stuck at 4 microns, I took a can of duster and sprayed it directly at each connection along the way to the MFC. I didn’t notice any jump in pressure, would this be acceptable?

What a long day it’s been…
Post Reply

Return to “Images du Jour”