FICS II Planning and construction

For posts specifically relating to fusor design, construction, and operation.
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Steven Sesselmann
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Re: FICS II Planning and construction

Post by Steven Sesselmann » Mon Feb 15, 2016 12:16 am

Werner Engel wrote:Hi Steven!
Just viewed your Video.
Congrats to your SCADA software with Labview! It seems to work perfectly.
How did you remote controll your Glassmann? Using a variable Input or serial communication?
My Turbo pump Controller also has a serial connection - but as it is RS 485, it's a little more time consuming to use it in Labview.
Please keep telling us about your USB connection solution being on high voltage - and how it works!
Werner, thanks, the instruction video you sent me was a good help. I am still using Labview evaluation software, but my son is a third year physics student, so with his collaboration we should be able to buy the student version. I had a look around and there isn't many open source programs that will work like this.

My Glassmann power supply has inputs and outputs at the back for analogue control, it's 0-10V. The DAQ only outputs 0-5V but fortunately it's a 125kV/16mA supply and my initial experiment is designed to not go over 60 kV and its unlikely to need 8mA so this gives me good control for what I need.

I have not started on the floating DAQ yet, but the plan is to have an MKS pressure controller and a DAQ with two 18V batteries connected by fiber optic USB cable to the computer. I will just use an LM7805 to draw some power from the battery for the hot end of the USB to optical connection.

First I must build the tubes and the chamber and get the system under vacuum, before I start working on the gas flow controller.

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

John Futter
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Re: FICS II Planning and construction

Post by John Futter » Mon Feb 15, 2016 5:37 pm

Steven
It is very easy to up the gain of the Glassman inputs by 2 to get 0-5 volt control.
Just two resistors to change to get 0-5V voltage and current control

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Steven Sesselmann
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Re: FICS II Planning and construction

Post by Steven Sesselmann » Wed Feb 17, 2016 1:32 am

John Futter wrote:Steven
It is very easy to up the gain of the Glassman inputs by 2 to get 0-5 volt control.
Just two resistors to change to get 0-5V voltage and current control
Good thinking John,

I was thinking outside the box in in therms of an opamp or comparator, but your suggestion makes more sense, I just need to track down the VD on the board.

Thanks..

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

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Steven Sesselmann
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Re: FICS II Planning and construction

Post by Steven Sesselmann » Sat Apr 23, 2016 12:07 pm

F.I.C.S. Update

I received the CNC machined discs last week, and they were a pretty close fit.
Disks - 4.jpg
I only needed to do very slight adjustments to the centre ring for a perfect fit with the glass discs.
This was lucky, because it was much easier to trim a bit off the aluminium than the glass, and
if the fit had been too loose I would have been in trouble.
Disks - 3.jpg
Here you can see the discs stacked with the 10 mm glass discs,
each hole diameter is 6 mm wider so the chamber is tapered.
Disks - 1.jpg
Each aluminium disc is ground against the glass plate with 50µ aluminium oxide paste
to make the surface flat. This process is taking longer than I expected because the
surface is quite large.
Disks - 2.jpg
Here one can see one side of the accelerator stack ground and assembled
but not yet glued. I intend to glue the whole chamber together in one go and
clamp it for drying. On the left one can see the end cap, made from solid
aluminium with hemisphere chamber and KF25 vacuum ports.

twin stack.JPG
Here are the twin stacks ready for assembly when the fusion chamber arrives.
All the discs have been ground flat. I ended up using a machine to turn the discs
while grinding, but it still took more than 10 hours.

The actual 6" fusion chamber has not been completed yet, it will be CNC machined in two halves from a solid piece of stainless steel and welded together. The engineering shop is looking around for the steel, hopefully we can find an off-cut that size. Although this chamber will be constructed the same way as my last one, it is much bigger and has twice as many layers, so I am quite nervous about getting it to hold high vacuum, if it leaks I have no choice but to break it open again, so this just has to be right the first time.

Applying the right amount of glue is going to be another challenge, latex forms a skin very fast, and I can't have any excess glue running into the chamber as it will be impossible to remove.

Slow steady progress here..
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

cynthiamyra
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Re: FICS II Planning and construction

Post by cynthiamyra » Tue May 31, 2016 7:03 am

Thanks for sharing your project.

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Steven Sesselmann
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Re: FICS II Planning and construction

Post by Steven Sesselmann » Sun Jun 05, 2016 12:14 pm

Time flies, it's been a month and a half since I posted a progress report, I have been busy with other things, but I also had to wait a long time for the final parts to get finished.

After putting a lot of pressure on the engineer I finally received the last two critical parts for the stack last week. The custom made vacuum duct made from 50 mm stainless steel pipe is TIG welded to an ISO100 blank and fits onto the Varian turbo pump, it has two NW25 nipples which will connect to either end of the chamber. I gave it a bit of a polish to make it look a bit sexy.
FICS - 1.jpg
50 mm Vacuum Duct with ISO100 Flange to NW25
I blanked off the NW 25 ends and pulled a vacuum to see if the tube had any obvious leaks and it appeared to hold vacuum pretty well, after a 20 minute pump down to 1 micron I turned off the valves and left it over night, the pressure had risen to 2000 micron, but considering it was the first pump down and a very small chamber (only the tube) I think that's okay.
FICS - 2.jpg
Vacuum gauge after 24 hours.
Then came the difficult work of preparing and gluing the stack together. preparation has taken me weeks. Each aluminium disc has been ground against the matching class disk with 50 micron aluminium oxide to produce a flat surface, this is essential to achieve a good seal.

With all the discs prepared and cleaned with acetone I set aside all day Sunday to glue the stack together, it was challenging to say the least. The trick is to keep everything 100% clean and apply exactly the right amount of glue without making a mess (easier said than done).

I found the best way to apply the latex glue was with a plastic squeeze bottle with a nozzle, applying a thing bead around the ring 2/3 from the centre, then carefully place one disc at the time onto the glue and allow the capillary effect to draw the glue across the disk. Too little glue and the gap wont fill and too much glue and it will run into the chamber.

Fortunately I designed the discs with a small lip towards the chamber which prevented excess glue running into the chamber. As can be seen from the photo some glue overflow on the outside is obvious, but this wont be a problem as the glue remains between the glass discs, and in any case it is not conductive when dry.

It wasn't necessary to clamp the stack, as is extremely heavy and gravity is more than enough to keep it clamped, the middle chamber which is a 6" hollow sphere machined from a solid stainless steel bar weighs at least 25 kg.

The end caps with the NW25 fittings are machined from solid aluminium and will be at ground potential during operation.

Slightly above center on the reaction chamber a small 1/8" Swagelok fitting can be seen, this is where the Deuterium gas supply will enter the chamber.

I expect it might take a couple of weeks before the latex has dried up to a point where I can pull a vacuum on this chamber, and then it might take another couple of weeks before all the water has been pulled out. As it is winter here now, and fairly wet and cold, I might get a small heater to speed up the process.

Once I pull a vacuum on this chamber I will back fill the chamber with argon and do some plasma cleaning of the chamber to get out any impurities.

So far I am reasonably pleased with how it's all coming together, but still some way to go.
FICS - 3.jpg
Double ended stack after gluing
Here is an image of the 6" chamber before it was welded together, it wasn't cheap.
chamber.jpg
6" Chamber

Thanks for reading...
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

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Dave Xanatos
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Re: FICS II Planning and construction

Post by Dave Xanatos » Sun Jun 05, 2016 1:05 pm

Thanks for that. The possibility of a self-sustaining fusor is immensely interesting to me. Looking forward to updates greatly!

Dave
It would take decades of work, by thousands of scientists, in a particle accelerator powered by dump trucks of flaming grant money! - Professor Farnsworth/FUTURAMA

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Steven Sesselmann
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Re: FICS II Planning and construction

Post by Steven Sesselmann » Sat Jul 23, 2016 7:11 am

Hi Guys,

Just a brief report to keep everyone updated on my FICS experiment. The assembly of the plasma chamber was a complete success and now since I repaired the Turbo pump I have now had the system under vacuum for a week and it's holding tight.

I am now working on the gas handling system and the floating DAQ with fibre optic connection the the PC.

More pictures and comments here on my site:
http://www.gammaspectacular.com/phpBB3/ ... 72c26#p807

Steven
160723 - 1.jpg
FICS Experiment
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

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Werner Engel
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Re: FICS II Planning and construction

Post by Werner Engel » Sat Jul 23, 2016 8:20 am

wow - the LabView user Interface looks veeeery nice! And I'm waiting for your first DAQ values and if there are any groundloop issues.
If I understand your concept right, you put the MFC with it's electronics on high potential. Why did you not try to isolate the gas pipe to the chamber? This would make it much easier. Or is there another reason for this?

Have fun,
Werner

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Steven Sesselmann
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Re: FICS II Planning and construction

Post by Steven Sesselmann » Sat Jul 23, 2016 8:49 am

Werner,

Running a gas line across a high voltage potential doesn't work, it will light up like a fluorescent tube and become conductor.

I already have one of the DAQ's working, initially I had a grounding problem which caused the DAQ to crash, but I solved this by bringing all the ground wires back to one point.

Still waiting for the second DAQ to arrive.

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

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