Archived - Kitchenaid fusor first light

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Wyatt
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Archived - Kitchenaid fusor first light

Post by Wyatt » Fri May 29, 2009 2:43 am

After futile attemts to determine the cause of my rough vacuum with leak searching and chamber sealing I realized that it was not my vacuum manifold or chamber that was keeping me from plasma but my crappy old rotary pump. The new pump arrived last night and I hooked it up to my demo fusor. Evidently it was the vacuum pump and the new pump pulled a high enough vacuum for plasma without a hitch. Although it was probably faulty equipment again my attempts to measure the x-rays produced were unsuccesful. I need to invest in a non cold war era quality geiger counter. I plan to gather data for the science fair on x-ray emissions with different pressures, voltages, and gasses. The picture below shows the fusor running at roughly 15kV. Also, stainless steel electric mixer bowls make very cost effective and strong bell jars. The plastic lid on mine made a perfect vacuum gasket.

Wyatt Paul
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plasma 1.jpg
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fusor 2.jpg
fusor 2.jpg (639.59 KiB) Viewed 3405 times

Tyler Christensen
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Re: Kitchenaid fusor first light

Post by Tyler Christensen » Fri May 29, 2009 4:26 am

A great example of a low-cost plasma generator. Nice job!

Regarding the x-rays, do you have a high voltage probe to measure the actual voltage or are you just assuming it's 15kv based on the power supply's rating? It looks like a small neon sign inverter which won't work to get anywhere near x-rays. That type of power supply can't sustain the current at it's rated voltage. In fact you'd be lucky to even get 1000 volts at standard plasma operation. I'd suggest using a high voltage probe to test your actual voltage. You need a minimum of 10kv to get any xrays at all but usually closer to 15kv.

Good luck on your research project! Hope you can get some x-rays. Just be careful of shielding it.

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Mike Beauford
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Re: Kitchenaid fusor first light

Post by Mike Beauford » Fri May 29, 2009 2:16 pm

Nice job! This is classic home brew, pull yourself up by your boot straps development! Nicely done!
Mike Beauford

Wyatt
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Re: Kitchenaid fusor first light

Post by Wyatt » Fri May 29, 2009 2:53 pm

Your assumption to whether or not I was assuming was correct, I was just going off of the rating on the NST. It's a very small one which makes 15 kV seem very doubtful and currently there is no voltage equipment connected. I'm thinking about using a couple of NST's in parallel to put out an adequate voltage.

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Richard Hull
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Re: Kitchenaid fusor first light

Post by Richard Hull » Fri May 29, 2009 3:16 pm

Great job, Wyatt. You are added to the Plasma Club.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

Dan Tibbets
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Re: Kitchenaid fusor first light

Post by Dan Tibbets » Fri May 29, 2009 4:55 pm

Congradulations. Now for a couple of questions and comments. It looks like your vacuum connection is bearing all of the weight. To avoid torsion and leak developement, you might wish to add some legs. Based on your glow discharge I'm going to guess your vacuum when the picture was taken was ~ 150-300 microns, or perhaps a little higher if your voltage was lowWhat is the base plate- metal?. How is the vacuum fitting attached- welded, bolted, threaded, epoxied? Are you using a gasket or grease?


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DaveC
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Re: Kitchenaid fusor first light

Post by DaveC » Fri May 29, 2009 7:06 pm

Wyatt -

Let me add a "Well Done!" to the group's congrats. Those SS bowls make a very photogenic presentation, too. Science can usually be good and pretty.

I would tend to agree that your voltage is probably lower than the NST's 15 kV nameplate. The glow discharge is in your picture suggests pressures above 10 microns, which is not bad for a rotary pump attached to equipment, so you are most likely drawing all the current the NST can deliver.. and taking the corresponding voltage drop.

Nice work, and thanks for the pictures.

Dave Cooper

Wyatt
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Re: Kitchenaid fusor first light

Post by Wyatt » Fri May 29, 2009 7:50 pm

The vacuum manifold is supporting the entire weight of the fusor, mainly for aesthetic purposes. I made a vacuum port with a washer and a brass hardwarestore fitting and used JB weld to epoxy it on. There is quite a bit of surface area for the epoxy to adhere to but legs will probably added as a precaution. The baseplate is kindof a mystery metal, it was just on hand in the metal shop at school. I suspect it's mild steel judging by the appearance and lack of corrosion resistance. As I said before, there is a gasket made from the lid that came with the mixing bowl. It is pliable yet hard and has a very flat smooth face on the bottom of it. I lubed the rim of the gasket with good ol' vaseline to fill the little cracks. Where the gasket contacts the baseplate was also polished to a mirror by a cotton wheel.

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Re: Kitchenaid fusor first light

Post by abhaylett » Fri May 29, 2009 8:19 pm

Congratulations on having built an elegant demonstration fusor, Wyatt. And that's a good picture of a plasma bugle that you included!

Alex & Ben

Tyler Christensen
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Re: Kitchenaid fusor first light

Post by Tyler Christensen » Fri May 29, 2009 10:16 pm

I don't think you'll get x-rays off of even parallel NST's. They simply can't provide necesary voltage, they're not designed to. You can read more about why they don't work with a search. I had 2 12,000 volt transformers (larger iron-core tranformers rather than the inverter that yours appears to be) and in parallel I still got a max of 2000 volts at 100micron pressure.

One way would be to get a diffusion pump and pull the pressure down to zero then use a bleed needle valve to bring the pressure up to about 15 microns and at this point you will have a low enough pressure to allow lower current and thus more voltage. You could possibly get x-rays with a few in parallel with this, but the vacuum equipment would cost you I'm guessing more than your budget.

I would suggest you try to hunt down either an x-ray transformer or a high voltage lab power supply. Both of which aren't cheap, but if you find a good deal used and shop around surplus you might be able to get something. I got an x-ray transformer rated for 100,000 volts .25A on ebay for $110 a few weeks ago.

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