Electron Gun Success

24 06 2012

All photos

Today we tested the electron gun in the chamber, and we detected a negative potential on the Langmuir probe, which means it worked!

Negative nine volts on the Langmuir probe

Fuck yeah!

Here’s what we did

1) Added a faster-acting fuse to the power supply

the new 4A fuse is underneath the black shrink-wrap

We already have a .5 amp fuse to protect the light bulb filament, but this new one  takes less time to actually blow once its current rating is surpassed, so if the cathode arcs to the chamber wall and pulls a large current, this fuse will blow quickly, preventing damage to the chamber.

wide shot of the setup

2) Closed the electron gun assembly in the chamber, connected to feed throughs, and set up the Langmuir probe.

The Langmuir probe is a wire with one end in the path of the electron beam, and the other attached to a multimeter set to volts DC

3) Powered up the vacuum system.

Because there was so much stuff in the chamber, there was also (presumably) a lot of trapped air which leaked out slowly as we pumped down, so the vacuum wasn’t super deep, but it was deep enough for our purposes.

3) Powered up the e-gun.

The cathode immediately started to glow, amd as we turned up the voltage across the cathode, the Langmuir probe started to register a negative potential.

We could not get potential on the Langmuir probe unless we powered up both the cathode and the accelerator, so we concluded that it must be the result of a beam.

There were also a couple of other interesting things we noticed.

Changes in the voltage of the accelerator did not seem to affect the beam intensity. We brought the potential on the accelerator from +500 down to ~+250, and got similar readings on the Langmuir probe.

Changes in the voltage (and current) to the cathode do affect beam intensity. We found that the greatest value we could get on the probe was about -12 volts, using about 90 to 100 volts AC across the cathode. As we kept increasing the cathode voltage/current beyond that, the Langmuir probe started heading towards zero, until the fuse blew.

After this, the Langmuir voltage started to head toward zero.

A little hard to see, that’a 10.59 volts on the Langmuir, and 102.5 volts on the cathode.

We don’t know what is causing this.

Another cool thing we noticed was the effect the electron gun had on the vacuum. Leaving the beam at maximum intensity caused the vacuum meter to show increased pressure. We were literally filling vacuum space with electrons.

Weird to see the the materiality of electrons demonstrated in such a concrete way.

But all that aside, this is a big step for us. From here, getting that electron beam shining into the center of the Polywell shouldn’t be too hard. If we succeed in that and document our results, we will have performed real, original research on the Polywell design. If we can get the potential well deep enough, maybe even do Polywell fusion.

So let me reiterate, FUCK YEAH

Domenick Bauer

Terrifying Power

4 09 2011

All photos.

Tonight I really experienced the power of the coil power supply. Whoa.

I’ve been working to increase the coil current from ~1.2kA to ~2.5kA.

Previously I discovered the coil discharge path had more DC resistance than expected.

I rewound the Polywell coils with 16 gauge wire (previously 18 gauge).

The 16 gauge DC resistance is 144 mΩ compared to 227 mΩ for 18 gauge wire.

I beefed up other wires on the coil discharge path (4 gauge):

Lets test the wiring with the dummy coil:

I took the power supply up to 100V… a small test charge…

When I fired, the noise from the coil made me flinch. It was never that loud before.

Lets turn up the power!

300V for second test.

When I fired the coil there was lightning! HOLY CRAP.  Look what happened:

The coil fucking wrapped itself around the transformer (electromagnetic forming). Then it discharged to ground:

So I haven’t measured it yet, but I think we are getting more current to the coils.

Electron Gun Operational!

29 08 2011

All photos.

Electron gun operational:

I got these high voltage supplies made for CRTs:

I still need to play around to get it focused, but a great start!

Deepest Potential Well Yet: 43 Volts

17 08 2011

All photos.

I’ve been running shots on the Polywell yesterday and today.

Just got my deepest potential well yet: 43 Volts.

10KV, 10mA on electron gun. 420V through coils. 8.5 millitorr air:

Be sure to check out the conditions I ran yesterday and today. Each shot has an oscilloscope photo with experimental parameters in caption.

Sydney Experiment: We Have Electron Confinement!!!

2 08 2011

All photos.

1 year,  7 months  and 8 days ago I learned of the copper coil Polywell that Joe Khachan and his team built.

I decided to repeat Joe’s experiment. Although challenging it seemed possible to achieve. I dubbed this endeavor the Sydney Experiment.

It took far longer than I expected to fabricate all the necessary parts for the experiment.

Today with great pleasure I ran the Sydney Experiment. Here we see what appears to be electron confinement:

This acquisition shows the floating potential of the langmuir probe.

This run was done with air plasma at 10 millitorr :

The electron gun was running  10KvDC @ 6.5mA:

The coil power supply was charged to ~ 400VDC:

This is just a first run. Now begins the actual experimentation and data gathering.

I do believe this is the WORLD’S FIRST AMATEUR POLYWELL!!!


The plasma during the run:

Cryogenic Cocktail Party

21 12 2010

All photos.

Last night my shop mate Stuart hosted a cryogenic cocktail party using his cryo-freezer and my liquid nitrogen.

The cryofreezer goes down to -120˚ C, cold enough to freeze liquor! We had vodka, bourbon, and gin ice cubes:

Ben made a silicon cast of a drinking glass to cast an ice glass:

We used the liquid nitrogen to make flash ice cream. Delicious:

I made white russian ice cream:


21 10 2010

All photos.

I have put the superconducting magnet into a persistent state!!!!!

Power supplies off, magnet still going!

Details to follow.


OK. Here it is. The units are in raw volts coming from the magnetometer and the current sensing resistor (0.008 ohms). The red is the current going into the superconducting coil, the white is the magnetic field. You can see that the current drops off, but the magnetic field persists. WIN!!!!

The magnetic field gradually falls off over the course of an hour.

This is the setup:

SC coil in the dewar:

Here is the schematic:

It was all controlled manually by switching the power supplies on and off.


6 07 2010

Wow. Last wednesday I woke up to a new world when the BBC and Gizmodo articles dropped.

Read all about it:

The definitive piece is by Quinn NortonNo Sleep ‘Til Fusion. This article is amazing – heartfelt and accurate. Quinn was there the night of the definitive fusion run. She even helped run the reactor. It was a night on the cusp. So exciting.

The same day Matthew Danzico from the BBC published Extreme DIY: Building a homemade nuclear reactor in NYC. This article took the story viral… it’s all over now!

CNN did a web writeup: Man builds web pages by day and nuclear fusion reactors by night.

CNN TV: Nuclear fusion the ‘Holy Grail’ of green energy?

CNN live interview.

My friend Olivia Koski was on this story from the start: Amateur Fusioneer Dreams of Clean Energy.


Gawker wins best of snark: The Gucci Employee Who Built a Nuclear Reactor in Brooklyn. “Artisanal nuclear fusion”. Pretty funny comments too.

Best comical artwork goes to racked.com: Gucci Web Developer Building a Nuclear Reactor in Brooklyn.

Most ridiculous headline goes to NYPOST: New Yorker found with nuclear reactor in Brooklyn warehouse. NYPOST also wins worst gross factual error: They state that I am building a fission reactor, which is incorrect… it’s fusion.

Worst comments go to Fox News: Gucci Designer Builds Nuclear Reactor in Brooklyn Warehouse.

We were covered by AOL, Yahoo! News, AP, France 5, Inside Edition, Huffington Post, Reddit, Digg, Hacker News, Slashdot, and a bazillion other outlets. I had reporters camping out at old apartments, calling my relatives, showing up at the lab. We got a visit from the NYFD and NYPD. Absolutely fucking nutz. The world went bonkers for this story.

Just as I planned…. mwahahahahaha!

Now everybody forget all about this so I can get back to work!  ;)


6 06 2010

All photos.

With the vacuum pump working again, I assembled the fusor and attempted a fusion run last night. It was a day frought with challenges, but in the end the bubble meter saw 4 bubbles in 2 hours and 40 minutes:

This shows beyond a doubt that we have fused the atom. During previous attempts we only produced a single bubble… which suggests fusion, but does not rule out a cosmic ray.

Science Journalist Quinn Norton was at the lab writing a story for Gizmodo. She witnessed and documented the fusion run:

Previously we were having problems with transient voltages spikes or EMFs crashing the data acquisition (DAQ) card. Today was a big test for the new transient voltage suppression system . It FAILED big time. But I learned something in the process.

I began by intentionally creating an unstable plasma to test the transient voltage system.  This crashed the DAQ every time.

Next I disconnected all wires to the DAQ to determine if the interference is coming through the wires or the air:

Without computer control I needed some way to manually adjust  the MFC. I hacked together a quick voltage divider using a 2KΩ potentiometer and a 9V battery:

This proved to work very well.

To control the high voltage from a distance I used the emergency stop button:

This also worked very well. At this point the reactor is completely under manual control. No computer necessary. Which will turn out to be a good thing.

So now we can test the DAQ with no physical connection to the reactor.

Surprisingly, I was able to crash the DAQ every time, even with no wires connected to it!

Quinn noticed the USB hub flickering during the plasma sparks and suggested it may be the failure point. I removed it, and indeed the system seemed less vulnerable to crashing:

At this point the DAQ seems to remain running in the face of sparking plasmas. Good.

Next I tried connecting one channel to the DAQ… a digital output channel to turn the high voltage on and off. I created a duty cycle function in labview to make it easy to bake out the chamber without melting the fusor grid. This is what it looks like running:

Next I bake out the chamber for an hour using a deuterium atmosphere @ 10 mtorr. The high voltage power supply is set to it’s maximum: 30Kv @ 10mA and the duty cycle is set to 75% @ ~ 0.09 hertz.

At first the computer controlled bake out was running smoothly. About 15 minutes in I get a computer crash. Restart. It runs for about 7 minutes and crashes. Try again. 5 minutes and it crashes. The crashes in increase frequency until I am getting nowhere.

At the point I switch the system over to full manual control and begin the metered fusion run. A fresh bubble detector was unboxed and activated.

(so fresh and so clean)

For the main fusion trial the deuterium atmosphere was at 10 mtorr, high voltage set to it’s maximum: 30Kv @ 10mA. The procedure was to run the system at full power until the plamsa became unstable and started sparking. This instability seems to correspond to the grid becoming red hot, so the plasma instability may be due to thermionic emission.

The bubble detector was activated for 2 hours and 40 minutes. The plasma was running for some unknown fraction of that time. 4 bubbles were detected.

Challenges remain for controlling this wily beast with a computer.

FIRST FUSION!!!!!!!!!!!!!!!

15 11 2009

I’ve been doing trials on the fusor all night. Finally GOT IT. WE HAVE FIRST FUSION. LOOK AT THIS BUBBLE:

I had the Glassman power supply  maxed out, and the deuterium pressure at ~9 millitorr. The plasma was borderline unstable due to low pressure. The focus of the plasma was maximal. There was a sharp uptick in activity from the geiger counter. The limiting factor was the grid kept heating up and glowing red. I had to cool it off to repeat each trial.


This is how it makes me feel:



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