3. "The Neutron Club"

These people have operated a neutron producing fusor or fusion system.
(normally d-d fusion): 

          Richard Hull - 10e5 neutron mark 3/99
          Scott Little
          Joe Zambelli - Half mega mark 12/01
          Tom Ligon
          Michael Li - winner $75k Intel scholarship (fusor)
          Mike Amann
          Jon Rosenstiel - Mega neutron mark 10e6 11/02
          Gerardo Meiro - First non-US neutron Club member
          Phillip Fostini
          Carl Willis - advanced activation work
          Larry Leins - pulsed fusor work
          Craig Wallace - winner $1.5k Intel 2nd place (Fusor)
          Frank Sanns
          Brian McDermott
          Fergus Noble & Henry Hallam - first UK neutron members
          Adam Parker - winner of $10k Alabama scholarship in science
          Mark Langdon
          Thiago Olson
          Wayne Rodgers
          Eric Stroud
          Wilfried Heil & Noemi Zudor - Smallest fusor ~3" diameter
          Raymond Jimenez
          Alex & Ben Haylett - first to use heavy water electrolysis
          Steven Sesselmann - first Aussie fusion, New Star system design
          Andrew Seltzman
          ***********
          Utrecht University fusor group, poster is Benjamin Brenny
          Group includes: Sander Mann, Dick Abma, Thijs Krijger, Remco Van den
                          Dungen, Nivard Kagie
          ***********
          Bob Heil
          ***********
          Peninsula College - student group
          Ho Yee Hui, Derek Madison, Devon McMinn, Sarah Mangiameli
          Chris Milroy, Aaron Stoll, Jeff Zirul
          ***********
          Roman Radtke
          Louis Franzel
          Taylor Wilson - Youngest fusioneer - 14 years old.
          Thomas Rapp
          Tyler Christensen
          Ben Bartlett
          Doug Coulter & Bill Fain - first cylindrical fusor
          Matthew Honickman
          Jason Heidecker
          Mark Suppes

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.

I added a piece of 80/20 to support the weight of the HV feedthrough. This makes it much easier and safer to install (I dropped it and broke a piece before):

Summary:

2 hours of bakeout prior to metered trial.

Calibration on the bubble detector label: BD-PND, 25 b/mrem(2.3 b/uSv).

Bubble detector is 95mm from the center of the grid.

We got a single bubble during an 8 minute run:

Towards the end of the experiment we noticed a wild outburst of geiger activity while the fusor was _not running_. Not sure what this means. We got it on video:

Using twitter as an experiment log worked very well. It helps capture details you notice along the way with timestamps.

Previously the glass tube was just hanging there waiting to be broken off.

Mounted all the peripheral  electronics:

These upgrades are all about murphy’s law – getting the equipment secured and off the ground prevents an accidental kick from disconnecting wires.

Added a proper mount for the video camera and geiger counter probe:

There was something so satisfying about this particular upgrade. Here is a wide shot of the fusor:

I’ve got plenty of 80/20 left for improvising rigs in the future.

Ultimately we want to build and operate a Bussard Reactor (Polywell).

Building and operating the Fusor is a necessary step towards building the Bussard Reactor. The Bussard Reactor is an outgrowth of the Fusor, and the two devices have much in common.

While we build the Fusor, we are also building the Bussard Reactor. We have the first prototype of the magrid, and we are testing the superconducting cable.

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:

I made headway with the command line program to control the fusor and record data in mysql via ruby. It’s currently setup to record vacuum chamber pressure, voltage and current according to the Glassman, and the effective flow rate of the mass flow controller. Currently I can enter commands to turn the high voltage on/off and set the flowrate of the mass flow controller. Next I want to control the voltage and current on the Glassman.

I also got a geiger counter:

It takes two D batteries. There is a BNC connector for headphones. I have a BNC connector on order with mcmaster. In the meantime I improvised a connection to some computer speakers to test it out. Seems to be working. It picks up the expected background radiation producing that erie clicking sound. You can definitely hear an uptick in the clicks when I run the Fusor.

I’m working towards producing a comprehensive mapping of this device’s performance envelope using computer control to search the parameter space and record the results.

This is all so fun and exciting.