Emma - Fusor Number 1. First deuterium run

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.
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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

Post by Richard Hull »

Beam patterns are indicative. symmetrical is the ideal. I would suspect 1. a sharp point at the copper gasket that is raised ever so slightly off the plane of the flat surface. Note: there could also be a sharp edge on the mating internal connecting receptacle or 2. A very minor and unsuspected leak at the gasket. Inspect that area of the gasket or knife end. something in that extension of the pattern to the edge is acting as an electrostatic beam attractor.

You might start a new thread now that you have you fusor fusing. This one is rather long now. Typically, each time something new comes along in your effort like this beam pattern you might start a new post with a title like "Odd beam pattern in my fusor" and let it develop. Now that you are truly one of the elites, we would rather your future posts deal with a single image or question in the various forums available that relates to the issue involved.

Remember, image du jour is not the only place for images. This beam post and its image might go better in the construction forum or in the vacuum forum. You will get the hang of this as you go. In short if you have something curious or puzzling with a image or not post to a forum that is related. In this manner it can be searched in a forum where folks might expect to find it and related subjects that also have images associated to the topic.


A posted thread should go on only so long as replies to it original thrust are helpful, valid and until the subject is effectively exhausted.

While you are a relative "newbie" you are also a very intelligent, capable and advanced newbie having done so much in so short a period of time.
Spread you wings and be a regular poster in such forums as seem most appropriate with an illustration or image there to instruct us or question us.
Remember, you can teach us a few things if you find something amazing and test our abilities to answer conundrums.

I attach a classic example of using the image du jour by myself to talk about hamfests and to show the booty of electronics and detection gear to be found at such events. As it is all about hamfesting and not the attached images it is an outlier which is posted to get electronics that might be used in fusor work at a bargain price, in person where you and touch what your are buying and bargain for it.

viewtopic.php?t=14581


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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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Image

Quick photo update: the re-build has done wonders for the cleanness of the chamber, aside from the beam its crystal clear and neutron counts are up.

Secondly - I've discovered that those Hoizon PEM cells are highly temperature dependant, as you would expect. Below about 17c not only do you get very poor gas flow but also, if left overnight, visible condensation on the outlet tube. 30 second very gentle blast with an heat gun to pre-heat works a treat while I'm waiting for the workshop heating to get going.
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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

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I have all of my fusor lab unheated as an attachment to my home with almost the same square footage as my home. I suffer from the winter doldrums so far as fusor work is concerned. I can work in my lab in the winter, but only in an isolated area where I use 20lb propane tank heater to take the chill off a small local work area at a bench area at the opposite end of the lab from the fusor.

I feel for your having to warm your PEM cell and enjoyed your report of its getting balky at 17 degrees. While I use only tanked deuterium, I am sure it is of interest to those using the PEM cell that you report some issues at lowered temperatures. I think most fusioneers tend to work in areas that are either in their homes or heated garages or out buildings. My large lab is just too big to heat in the winter. Propane has gone up. A $29.00 refill on my tank is now $39.00. Fortunately, I tend to only need 3 refills during the winter as my simple, non fusion experiments tend to move to my heated up stairs lab area within my home.

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: Emma - Fusor Number 1. First deuterium run

Post by Matt_Gibson »

I abandoned the PEM cell due to condensation forming, bad enough that it made its way into my chamber. I now use bottled deuterium. A lot more $$$ but much much easier.

-Matt
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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Condensation that bad, you would think the membrane had burst! Warming it first seems to help a lot. I have been looking again at prices for bottled D2, quite like Richard's arrangement of filling a very small cylinder for each run to a known pressure.

We use woodstoves both for the house and workshop, the house being from the 17th century has terrible insulation, it takes ages for things to get warm. I also have a small diesel heater pointed at the main work area, which helps and is not too bad to run.
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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

Post by Richard Hull »

Keep warm this winter, for sure. When growing up, we heated with coal. Being the older boy, I had to get up at 3AM and throw a few fresh lump or two in the stove in our bedroom and shake down the grates so my younger brother and I could keep warm. Lots of bedding and blankets helped.

Running a fusor with cold fingers and toes is no fun. Still, having a large 700 sq. foot lab is more than most of us have, even if unheated.

All the best in future with your fusor.

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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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

After more debugging with the PEM system, I hit a new record today 13.29 MRem/H showing on the Ludum at 35kv 4.5ma, which I make 385,410 n/s.
I'm hoping a few wall loading runs will yield the 500k mark, but we will see. 3600 CPM on the silver activation, improved slightly after messing around with the position of the moderator blocks. Have some Indium foil on its way to experiment with to, but not sure if the neutron output would good enough for a detectable activation.

On the PEM setup. I'm finding that these ground glass syringes start to get stuck at the merest suggestion of dust, which seems to result in air getting sucked into the system, presumably around the plunger. So swapped back to using the plastic ones and moved it all into a box with dust filters, that combined with warming the cell and using some silica gel to dry the gas all seems to be helping.
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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

Post by Richard Hull »

You are honing your operational skills. As they getter you results will follow. while fusion is technically easy with a fusor, the operation can be tricky which quickly falls into a well honed routine.

Indium is as easy as silver to activate. You will have no trouble. While also a good beta emitter like silver, Indium is a far better sturdy of gammas if you have a gamma ray spectrometer.

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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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Yes its defiantly getting easier to operate, it's now very routine. After swapping out the lamps I'm using for primary ballast to higher wattage ones, what I think should be the 500k mark (blue line) was pretty easy to reach. We now have a bit more current to play with.

Likely don't need these at all, but with 4 bulbs in parallel it's good to be able to select the current limit by switching some off, all 4 on = 12ma, 2 on 6ma etc. While operating I keep the filaments just at the point of barely visible glow, in this state they are quite responsive to any undesirable increase in current and impossible to ignore.

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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

Post by Richard Hull »

Excellent report with graph showing the rise in neutron count. However, what are the details on the bulbs? What are their type? do they have a number or wattage, what are their rated voltage in normal use? key details? Where are they in your power circuit?

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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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Useful details indeed missed there, my apologies. I'm using 400w 110v rated bulbs connected as below. They don't use anything like the full wattage to start to glow of course and as soon as they do the resistance ramps up rapidly. As I said though maybe not needed any longer or an ideal solution.

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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

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So you have 1600 watt lamp load bank there that is switchable. 400 watt 110 volt lamps are big! Or did you mean 4 -100 watt lamps?

Regardless, it is pretty neat idea to have a visual variable ballast on the input side of the AC line. Cool. This is interesting and never put forth here.

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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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Yes they are massive! D-Cell for scale:

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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

First indium foil activation, this was a fun one and worked first time. 15mins in the fusor averaging 4.2e5 n/s 36kv 6ma.

I did a video of the first 15 minutes, compressed into 1 minute, the survey meter was on 0.1x. This is making me very much want to get a gamma spec setup.

https://youtube.com/shorts/CYHtGPmaW-8?feature=share
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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Since switching over I've found these little 11l Hydrostick cartridges are great, no more messing around the pem cell. Constant pressure for as long as you need. The switch has sorted my condensation issues as well and neutron counts are up as a result.

Also built a simple arduino based stepper motor system for the leak valve, for some super precision control, which I need to install and test.

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Re: Emma - Fusor Number 1. First deuterium run

Post by Matt_Gibson »

I could be wrong, but this might be the first example of using the hydrostick for deuterium supply. Could you give some more details about it?

-Matt
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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

Post by Richard Hull »

Great work Emma! We look forward to your reports on this system and how it works out for you.

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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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Matt - there was an excellent thread a while ago by Andrew Seltzman with a great deal of technical details on both the cartridges and the filling station.

viewtopic.php?t=13292
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Re: Emma - Fusor Number 1. First deuterium run

Post by Dennis P Brown »

Really top rate work, Emma. I understand the issue with a 17th century house - part of my house was built in the early 18th century; yes, there was no such thing as insulation then but certainly horsehair plaster, semi-finished tree shaped beams using wood dowels and a few handmade metal nails are certainly there as I've found out the hard way!
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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

A little update. Now that the power supply has been upgraded to support a higher voltage (60kv+) the feedthrough has started having arcing issues. This is not that surprising given that its only rated for 30KV.

After some investigation, this seems to have actually been on the air side and exacerbated by moisture/dust on the ceramic. It was a little better after a clean. Corona noise was still present over about 50kv though, so I am currently experimenting with an added oil tank to improve the feedthrough.

This is a simple ABS print. Now ABS starts to deform at fairly low temperatures, so even though there is a thick rubber seal between the fusor and the plastic for some thermal separation, the temps will still need to be watched.
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Richard Hull
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Re: Emma - Fusor Number 1. First deuterium run

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Be advised, regardless of seals, USP mineral oil (non scented) has a way of getting around many types of seals. You do not want to come out to your fusor and find it and the table it is on or the floor covered with oil.

I had a real battle when making my own rolled capacitors for my Tesla coil work back in the early 90s.
Good luck

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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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Thanks Richard, that sounds like a lesson learned from harsh experience!

The mess of it leaking is a bit worrying. 900ml of transformer oil all over the place would not be fun to clear up, at least it wouldn't short everything out like water would. Its been a week and nothing has leaked out so far.

If this functions ok performance wise I will look at constructing an all metal tank. Possibly by welding a SS container to a double sided cf flange, so I don't have to weld directly to the feedthroughs CF.
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Re: Emma - Fusor Number 1. First deuterium run

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Sacrificial double sided flanges are a great solution if a weldment is needed on an insulator. I hope your seal holds. Some rubber/polymer seals can deteriorate over time and become permeable. The heating and cooling cycling, as you note, might speed up issues with the seal.

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
William Turner
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Re: Emma - Fusor Number 1. First deuterium run

Post by William Turner »

Viton or Buna N (Nitrile) should be fine with transformer oil. Viton A will have lower permeability with <30% compression.

Natural rubber and EPDM (very common with fittings intended for use with water) both are terrible.

https://www.coleparmer.com/chemical-resistance (Select Oils: Mineral)

Be careful with SLA/FDM printed parts, they tend to be porous and can leak over long periods of time without sealing (vacuum impregnation with a low-viscosity epoxy should work).
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Emma Black
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Re: Emma - Fusor Number 1. First deuterium run

Post by Emma Black »

Thanks William, I was initially using a Vitron seal but I wasn't happy with the amount of force needed on the printed part to compress the seal against the top of the CF fitting. So I switched to using some high temperature automotive liquid gasket, it will be a bit messy to remove but I have a lot more faith it wont leak.

For the prints normally resin impregnation would be the way forward, however the thing was too big to fit in any chamber I had on hand. So version 2 was printed with a double wall and resin poured in-between.

Lab assistant for scale.
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